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    Identification of New Soluble Factors Correlated With the Development of Graft Failure After Haploidentical Hematopoietic Stem Cell Transplantation. Weber Gerrit,Strocchio Luisa,Del Bufalo Francesca,Algeri Mattia,Pagliara Daria,Arnone Claudia Manuela,De Angelis Biagio,Quintarelli Concetta,Locatelli Franco,Merli Pietro,Caruana Ignazio Frontiers in immunology Graft failure is a severe complication of allogeneic hematopoietic stem cell transplantation (HSCT). The mechanisms involved in this phenomenon are still not completely understood; data available suggest that recipient T lymphocytes surviving the conditioning regimen are the main mediators of immune-mediated graft failure. So far, no predictive marker or early detection method is available. In order to identify a non-invasive and efficient strategy to diagnose this complication, as well as to find possible targets to prevent/treat it, we performed a detailed analysis of serum of eight patients experiencing graft failure after T-cell depleted HLA-haploidentical HSCT. In this study, we confirm data describing graft failure to be a complex phenomenon involving different components of the immune system, mainly driven by the IFNγ pathway. We observed a significant modulation of IL7, IL8, IL18, IL27, CCL2, CCL5 (Rantes), CCL7, CCL20 (MIP3a), CCL24 (Eotaxin2), and CXCL11 in patients experiencing graft failure, as compared to matched patients not developing this complication. For some of these factors, the difference was already present at the time of infusion of the graft, thus allowing early risk stratification. Moreover, these cytokines/chemokines could represent possible targets, providing the rationale for exploring new therapeutic/preventive strategies. 10.3389/fimmu.2020.613644
    Failed CTL/NK cell killing and cytokine hypersecretion are directly linked through prolonged synapse time. Jenkins Misty R,Rudd-Schmidt Jesse A,Lopez Jamie A,Ramsbottom Kelly M,Mannering Stuart I,Andrews Daniel M,Voskoboinik Ilia,Trapani Joseph A The Journal of experimental medicine Failure of cytotoxic T lymphocytes (CTLs) or natural killer (NK) cells to kill target cells by perforin (Prf)/granzyme (Gzm)-induced apoptosis causes severe immune dysregulation. In familial hemophagocytic lymphohistiocytosis, Prf-deficient infants suffer a fatal "cytokine storm" resulting from macrophage overactivation, but the link to failed target cell death is not understood. We show that prolonged target cell survival greatly amplifies the quanta of inflammatory cytokines secreted by CTLs/NK cells and that interferon-γ (IFN-γ) directly invokes the activation and secondary overproduction of proinflammatory IL-6 from naive macrophages. Furthermore, using live cell microscopy to visualize hundreds of synapses formed between wild-type, Prf-null, or GzmA/B-null CTLs/NK cells and their targets in real time, we show that hypersecretion of IL-2, TNF, IFN-γ, and various chemokines is linked to failed disengagement of Prf- or Gzm-deficient lymphocytes from their targets, with mean synapse time increased fivefold, from ∼8 to >40 min. Surprisingly, the signal for detachment arose from the dying target cell and was caspase dependent, as delaying target cell death with various forms of caspase blockade also prevented their disengagement from fully competent CTLs/NK cells and caused cytokine hypersecretion. Our findings provide the cellular mechanism through which failed killing by lymphocytes causes systemic inflammation involving recruitment and activation of myeloid cells. 10.1084/jem.20140964
    Signaling pathways involved in the T-cell-mediated immunity against Epstein-Barr virus: Lessons from genetic diseases. Latour Sylvain,Fischer Alain Immunological reviews Primary immunodeficiencies (PIDs) provide researchers with unique models to understand in vivo immune responses in general and immunity to infections in particular. In humans, impaired immune control of Epstein-Barr virus (EBV) infection is associated with the occurrence of several different immunopathologic conditions; these include non-malignant and malignant B-cell lymphoproliferative disorders, hemophagocytic lymphohistiocytosis (HLH), a severe inflammatory condition, and a chronic acute EBV infection of T cells. Studies of PIDs associated with a predisposition to develop severe, chronic EBV infections have led to the identification of key components of immunity to EBV - notably the central role of T-cell expansion and its regulation in the pathophysiology of EBV-associated diseases. On one hand, the defective expansion of EBV-specific CD8 T cells results from mutations in genes involved in T-cell activation (such as RASGRP1, MAGT1, and ITK), DNA metabolism (CTPS1) or co-stimulatory pathways (CD70, CD27, and TNFSFR9 (also known as CD137/4-1BB)) leads to impaired elimination of proliferating EBV-infected B cells and the occurrence of lymphoma. On the other hand, protracted T-cell expansion and activation after the defective killing of EBV-infected B cells is caused by genetic defects in the components of the lytic granule exocytosis pathway or in the small adapter protein SH2D1A (also known as SAP), a key activator of T- and NK cell-cytotoxicity. In this setting, the persistence of EBV-infected cells results in HLH, a condition characterized by unleashed T-cell and macrophage activation. Moreover, genetic defects causing selective vulnerability to EBV infection have highlighted the role of co-receptor molecules (CD27, CD137, and SLAM-R) selectively involved in immune responses against infected B cells via specific T-B cell interactions. 10.1111/imr.12791
    Interleukin-18 and cytotoxic impairment are independent and synergistic causes of murine virus-induced hyperinflammation. Tsoukas Paul,Rapp Emily,Van Der Kraak Lauren,Weiss Eric S,Dang Vinh,Schneider Corinne,Klein Edwin,Picarsic Jennifer,Salcedo Rosalba,Stewart C Andrew,Canna Scott W Blood Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening hyperinflammatory syndromes typically associated with underlying hematologic and rheumatic diseases, respectively. Familial HLH is associated with genetic cytotoxic impairment and thereby to excessive antigen presentation. Extreme elevation of serum interleukin-18 (IL-18) has been observed specifically in patients with MAS, making it a promising therapeutic target, but how IL-18 promotes hyperinflammation remains unknown. In an adjuvant-induced MAS model, excess IL-18 promoted immunopathology, whereas perforin deficiency had no effect. To determine the effects of excess IL-18 on virus-induced immunopathology, we infected Il18-transgenic (Il18tg) mice with lymphocytic choriomeningitis virus (LCMV; strain Armstrong). LCMV infection is self-limited in wild-type mice, but Prf1-/- mice develop prolonged viremia and fatal HLH. LCMV-infected Il18-transgenic (Il18tg) mice developed cachexia and hyperinflammation comparable to Prf1-/- mice, albeit with minimal mortality. Like Prf1-/- mice, immunopathology was largely rescued by CD8 depletion or interferon-γ (IFNg) blockade. Unlike Prf1-/- mice, they showed normal target cell killing and normal clearance of viral RNA and antigens. Rather than impairing cytotoxicity, excess IL-18 acted on T lymphocytes to amplify their inflammatory responses. Surprisingly, combined perforin deficiency and transgenic IL-18 production caused spontaneous hyperinflammation specifically characterized by CD8 T-cell expansion and improved by IFNg blockade. Even Il18tg;Prf1-haplosufficient mice demonstrated hyperinflammatory features. Thus, excess IL-18 promotes hyperinflammation via an autoinflammatory mechanism distinct from, and synergistic with, cytotoxic impairment. These data establish IL-18 as a potent, independent, and modifiable driver of life-threatening innate and adaptive hyperinflammation and support the rationale for an IL-18-driven subclass of hyperinflammation. 10.1182/blood.2019003846
    The Storm Beneath the Storm: MAS-HLH in Inflammatory Myopathies. Schulert Grant S The Journal of rheumatology 10.3899/jrheum.191274
    HSCT is effective in patients with PSTPIP1-associated myeloid-related proteinemia inflammatory (PAMI) syndrome. Laberko Alexandra,Burlakov Vasiliy,Maier Sarah,Abinun Mario,Skinner Roderick,Kozlova Anna,Suri Deepti,Lehmberg Kai,Müller Ingo,Balashov Dmitry,Novichkova Galina,Holzinger Dirk,Gennery Andrew R,Shcherbina Anna The Journal of allergy and clinical immunology BACKGROUND:Proline-serine-threonine phosphatase-interacting protein 1-associated myeloid-related proteinemia inflammatory (PAMI) syndrome is a novel genetic disorder, causing hypercalprotectinemia and hyperzincemia with inflammatory complications accompanied by cytopenia. Immunosuppressive and/or anticytokine therapy is of limited effect. OBJECTIVES:Because of cytokine production in nonhematopoietic tissues, the potential therapeutic effect of allogeneic hematopoietic stem cell transplantation (HSCT) in autoinflammatory disorders, including PAMI syndrome, has remained uncertain. METHODS:Five patients with PAMI syndrome underwent allogeneic HSCT with myeloablative (4) or reduced-intensity (1) conditioning regimens. Lack of PAMI disease control served as indication for the HSCT in 4 patients and myelodysplastic syndrome development in 1. RESULTS:All 5 patients engrafted; however, 1 patient at day +13 developed hemophagocytic syndrome, followed by graft rejection at day +17. After 5.5 months, a second HSCT was performed from an alternative donor. A further patient at day +116 developed an intense inflammatory syndrome with significant serositis and severe mitral and aortic valve regurgitation, controlled with adalimumab, tacrolimus, and prednisone. No other noninfectious inflammatory episodes, or acute or chronic graft-versus-host disease, occurred in any patient. At the last follow-up (median, 2.2 years), all 5 patients have predominantly or complete donor chimerism and adequate immune recovery and are free of any PAMI symptoms. CONCLUSIONS:Allogeneic HSCT seems to be an effective option to cure cytopenia and severe autoinflammation in PAMI syndrome and may be a curative option for other proline-serine-threonine phosphatase-interacting protein 1-associated inflammatory disorders with poor therapeutic control. 10.1016/j.jaci.2020.11.043
    IL-18 and infections: Is there a role for targeted therapies? Vecchié Alessandra,Bonaventura Aldo,Toldo Stefano,Dagna Lorenzo,Dinarello Charles A,Abbate Antonio Journal of cellular physiology Interleukin (IL)-18 is a pro-inflammatory cytokine belonging to the IL-1 family, first identified for its interferon-γ-inducing properties. IL-18 regulates both T helper (Th) 1 and Th2 responses. It acts synergistically with IL-12 in the Th1 paradigm, whereas with IL-2 and without IL-12 it can induce Th2 cytokine production from cluster of differentation (CD)4 T cells, natural killer (NK cells, NKT cells, as well as from Th1 cells. IL-18 also plays a role in the hemophagocytic lymphohistiocytosis, a life-threatening condition characterized by a cytokine storm that can be secondary to infections. IL-18-mediated inflammation was largely studied in animal models of bacterial, viral, parasitic, and fungal infections. These studies highlight the contribution of either IL-18 overproduction by the host or overresponsiveness of the host to IL-18 causing an exaggerated inflammatory burden and leading to tissue injury. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19). The damage in the later phase of the disease appears to be driven by a cytokine storm, including interleukin IL-1 family members and secondary cytokines like IL-6. IL-18 may participate in this hyperinflammation, as it was previously found to be able to cause injury in the lung tissue of infected animals. IL-18 blockade has become an appealing therapeutic target and has been tested in some IL-18-mediated rheumatic diseases and infantile-onset macrophage activation syndrome. Given its role in regulating the immune response to infections, IL-18 blockade might represent a therapeutic option for COVID-19, although further studies are warranted to investigate more in detail the exact role of IL-18 in SARS-CoV-2 infection. 10.1002/jcp.30008
    Reaching the threshold: a multilayer pathogenesis of macrophage activation syndrome. Strippoli Raffaele,Caiello Ivan,De Benedetti Fabrizio The Journal of rheumatology Macrophage activation syndrome (MAS) is a potentially fatal complication of rheumatic diseases. The condition is considered part of secondary hemophagocytic lymphohistiocytoses (HLH). There are similarities in genetic background, pathogenesis, and clinical and laboratory features with primary HLH (p-HLH). We describe findings in mouse models of secondary HLH, comparing them with models of p-HLH and the cellular and molecular mechanisms involved, and relate them to recent findings in patients with secondary HLH. A multilayer model is presented in which background inflammation, infections, and genetics all contribute in different proportions and in several ways. Once the "threshold" has been reached, inflammatory cytokines are the final effectors, independent of the interplay between different upstream pathogenic factors. 10.3899/jrheum.121233
    Cellular therapy: Immune-related complications. Oved Joseph H,Barrett David M,Teachey David T Immunological reviews The advent of chimeric antigen receptor T (CAR-T) and the burgeoning field of cellular therapy has revolutionized the treatment of relapsed/refractory leukemia and lymphoma. This personalized "living therapy" is highly effective against a number of malignancies, but this efficacy is tempered by side effects relatively unique to immunotherapies, including CAR-T. The overwhelming release of cytokines and chemokines by activated CAR-T and other secondarily activated immune effector cells can lead to cytokine release syndrome (CRS), which can have clinical and pathophysiology similarities to systemic inflammatory response syndrome and macrophage activating syndrome/hemophagocytic lymphohistiocytosis. Tocilizumab, an anti-IL6 receptor antibody, was recently FDA approved for treatment of CRS after CAR-T based on its ability to mitigate CRS in many patients. Unfortunately, some patients are refractory and additional therapies are needed. Patients treated with CAR-T can also develop neurotoxicity and, as the biology is poorly understood, current therapeutic interventions are limited to supportive care. Nevertheless, a number of recent studies have shed new light on the pathophysiology of CAR-T-related neurotoxicity, which will hopefully lead to effective treatments. In this review we discuss some of the mechanistic contributions intrinsic to the CAR-T construct, the tumor being treated, and the individual patient that impact the development and severity of CRS and neurotoxicity. As CAR-T and cellular therapy have redefined the concept of personalized medicine, so too will personalization be necessary in managing the unique side effects of these therapies. 10.1111/imr.12768
    Inflammatory and Infectious Syndromes Associated With Cancer Immunotherapies. Fishman Jay A,Hogan John I,Maus Marcela V Clinical infectious diseases : an official publication of the Infectious Diseases Society of America Immunotherapy using antibodies to immune checkpoint molecules or targeted chimeric antigen receptor-modified T cells (CAR-T cells) represent dramatic advances in cancer treatment. These therapies mediate immune-related adverse events that may mimic or amplify infectious presentations. Checkpoint inhibitor therapy may be associated with diverse irAEs including mild skin, endocrine, and autoimmune manifestations or severe inflammatory processes including colitis, pneumonitis, myocarditis, and shock. CAR-T-cell therapies may induce toxicities including cytokine-release syndrome with fevers and multiorgan dysfunction, CAR-T-cell-related encephalopathy syndrome with altered mental status and neurologic dysfunction, or hemophagocytic lymphohistiocytosis-macrophage-activation syndrome. Infectious risks may relate to prior cancer therapies or to treatments of inflammatory dysregulation, including corticosteroids and inhibitors of tumor necrosis factor-α and interleukin-6. Immune activation may unmask subclinical infections. Clinical approaches must attempt to identify infections in the face of immunotherapy-associated inflammatory processes. Empirical antimicrobial therapies should not be delayed based on the presumption of noninfectious syndromes. 10.1093/cid/ciy1025
    COVID-19: High-JAKing of the Inflammatory "Flight" by Ruxolitinib to Avoid the Cytokine Storm. Botta Cirino,Indrieri Alessia,Garofalo Eugenio,Biamonte Flavia,Bruni Andrea,Pasqua Pino,Cesario Francesco,Costanzo Francesco Saverio,Longhini Federico,Mendicino Francesco Frontiers in oncology Since SARS-CoV-2 outbreak in December 2019, world health-system has been severely impacted with increased hospitalization, Intensive-Care-Unit (ICU) access and high mortality rates, mostly due to severe acute respiratory failure and multi-organ failure. Excessive and uncontrolled release of proinflammatory cytokines (cytokine release/storm syndrome, CRS) have been linked to the development of these events. The recent advancements of immunotherapy for the treatment of hematologic and solid tumors shed light on many of the molecular mechanisms underlying this phenomenon, thus rendering desirable a multidisciplinary approach to improve COVID-19 patients' outcome. Indeed, currently available therapeutic-strategies to overcome CRS, should be urgently evaluated for their capability of reducing COVID-19 mortality. Notably, COVID-19 shares different pathogenic aspects with acute graft-versus-host-disease (aGVHD), hemophagocytic-lymphohistiocytosis (HLH), myelofibrosis, and CAR-T-associated CRS. Specifically, similarly to aGVHD, an induced tissue damage (caused by the virus) leads to increased cytokine release (TNFα and IL-6) which in turn leads to exaggerated dendritic cells, macrophages (like in HLH) and lymphocytes (as in CAR-T) activation, immune-cells migration, and tissue-damage (including late-stage fibrosis, similar to myelofibrosis). Janus Kinase (JAK) signaling represents a molecular hub linking all these events, rendering JAK-inhibitors suitable to limit deleterious effects of an overwhelming inflammatory-response. Accordingly, ruxolitinib is the only selective JAK1 and JAK2-inhibitor approved for the treatment of myelofibrosis and aGVHD. Here, we discuss, from a molecular and hematological point of view, the rationale for targeting JAK signaling in the management of COVID-19 patients and report the clinical results of a patient admitted to ICU among the firsts to be treated with ruxolitinib in Italy. 10.3389/fonc.2020.599502
    Janus Family kinase (JAK) inhibitors in HLH and severe COVID-19. Wilcox Ryan A American journal of hematology 10.1002/ajh.25985
    Spectrum of perforin gene mutations in familial hemophagocytic lymphohistiocytosis. Göransdotter Ericson K,Fadeel B,Nilsson-Ardnor S,Söderhäll C,Samuelsson A,Janka G,Schneider M,Gürgey A,Yalman N,Révész T,Egeler R,Jahnukainen K,Storm-Mathiesen I,Haraldsson A,Poole J,de Saint Basile G,Nordenskjöld M,Henter J American journal of human genetics Familial hemophagocytic lymphohistiocytosis (FHL) is an autosomal recessive disease of early childhood characterized by nonmalignant accumulation and multivisceral infiltration of activated T lymphocytes and histiocytes (macrophages). Cytotoxic T and natural killer (NK) cell activity is markedly reduced or absent in these patients, and mutations in a lytic granule constituent, perforin, were recently identified in a number of FHL individuals. Here, we report a comprehensive survey of 34 additional patients with FHL for mutations in the coding region of the perforin gene and the relative frequency of perforin mutations in FHL. Perforin mutations were identified in 7 of the 34 families investigated. Six children were homozygous for the mutations, and one patient was a compound heterozygote. Four novel mutations were detected: one nonsense, two missense, and one deletion of one amino acid. In four families, a previously reported mutation at codon 374, causing a premature stop codon, was identified, and, therefore, this is the most common perforin mutation identified so far in FHL patients. We found perforin mutations in 20% of all FHL patients investigated (7/34), with a somewhat higher prevalence, approximately 30% (6/20), in children whose parents originated from Turkey. No other correlation between the type of mutation and the phenotype of the patients was evident from the present study. Our combined results from mutational analysis of 34 families and linkage analysis of a subset of consanguineous families indicate that perforin mutations account for 20%-40% of the FHL cases and the FHL 1 locus on chromosome 9 for approximately 10%, whereas the major part of the FHL cases are caused by mutations in not-yet-identified genes. 10.1086/318796
    Harnessing CAR T-cell Insights to Develop Treatments for Hyperinflammatory Responses in Patients with COVID-19. Agarwal Sangya,June Carl H Cancer discovery Cytokine release and macrophage activation contribute to immunopathology after SARS-CoV-2 infection. We discuss approaches to decrease the morbidity and mortality in patients with COVID-19 by repurposing existing drugs previously developed for cancer therapy. 10.1158/2159-8290.CD-20-0473
    Sustained IL-4 exposure leads to a novel pathway for hemophagocytosis, inflammation, and tissue macrophage accumulation. Milner Joshua D,Orekov Tatyana,Ward Jerrold M,Cheng Lily,Torres-Velez Fernando,Junttila Ilkka,Sun Guangping,Buller Mark,Morris Suzanne C,Finkelman Fred D,Paul William E Blood Erythrophagocytosis and inflammation from activated macrophages occur in distinct clinical scenarios. The presence of CD8(+) T cells and interferon-γ (IFN-γ) production is required to induce disease in mouse models of hemophagocytic lymphohistiocytosis. We investigated the roles of a different class of proinflammatory cytokines, interleukin-4 (IL-4) and IL-13, in the induction of inflammatory tissue macrophage accumulation and/or hemophagocytosis. We found that large amounts of IL-4, but not IL-13, delivered via an implanted mini-pump or IL-4/anti-IL-4 complexes, lead to substantial YM1(+) tissue macrophage accumulation, erythrophagocytosis within the liver, spleen, and bone marrow, decreased hemoglobin and platelet levels, and acute weight loss. This effect is not dependent on the presence of antibody or T cells, as treatment of Rag2(-/-) mice leads to similar disease, and IFN-γ neutralization during IL-4 treatment had no effect. IL-4 treatment results in suppression of IL-12, elevation of serum IFN-γ, IL-10, and the murine IL-8 homolog KC, but not IL-6, IL-1β, or tumor necrosis factor-α. Finally, mice transgenic for IL-4 production developed tissue macrophage accumulation, disruption of splenic architecture, bone marrow hypocellularity, and extramedullary hematopoiesis. These data describe a novel pathophysiologic pathway for erythrophagocytosis in the context of tissue macrophage accumulation and inflammation involving elevations in IL-4 and alternative macrophage activation. 10.1182/blood-2009-11-255174
    Treatment of hemophagocytic lymphohistiocytosis with HLH-94 immunochemotherapy and bone marrow transplantation. Henter Jan-Inge,Samuelsson-Horne AnnaCarin,Aricò Maurizio,Egeler R Maarten,Elinder Göran,Filipovich Alexandra H,Gadner Helmut,Imashuku Shinsaku,Komp Diane,Ladisch Stephan,Webb David,Janka Gritta, Blood Hemophagocytic lymphohistiocytosis (HLH) comprises familial (primary) hemophagocytic lymphohistiocytosis (FHL) and secondary HLH (SHLH), both clinically characterized by fever, hepatosplenomegaly, and cytopenia. FHL, an autosomal recessive disease invariably fatal when untreated, is associated with defective triggering of apoptosis and reduced cytotoxic activity, resulting in a widespread accumulation of T lymphocytes and activated macrophages. In 1994 the Histiocyte Society initiated a prospective international collaborative therapeutic study (HLH-94), aiming at improved survival. It combined chemotherapy and immunotherapy (etoposide, corticosteroids, cyclosporin A, and, in selected patients, intrathecal methotrexate), followed by bone marrow transplantation (BMT) in persistent, recurring, and/or familial disease. Between July 1, 1994, and June 30, 1998, 113 eligible patients aged no more than 15 years from 21 countries started HLH-94. All had either an affected sibling (n = 25) and/or fulfilled the Histiocyte Society diagnostic criteria. At a median follow-up of 3.1 years, the estimated 3-year probability of survival overall was 55% (95% confidence interval +/- 9%), and in the familial cases, 51% (+/- 20%). Twenty enrolled children were alive and off therapy for more than 12 months without BMT. For patients who received transplants (n = 65), died prior to BMT (n = 25), or were still on therapy (n = 3), the 3-year survival was 45% (+/- 10%). The 3-year probability of survival after BMT was 62% (+/- 12%). HLH-94 is very effective, allowing BMT in most patients. Survival of children with HLH has been greatly improved. 10.1182/blood-2002-01-0172
    Pathogenesis of hemophagocytic syndrome (HPS). Larroche Claire,Mouthon Luc Autoimmunity reviews Hemophagocytic syndrome (HPS) is a clinicopathologic entity characterized by increased proliferation and activation of benign macrophages with hemophagocytosis throughout the reticuloendothelial system. Uncontrolled T-lymphocyte activation is responsible for increased T(H)1 cytokines secretion such as IFN-gamma, IL-12 and IL-18 that promotes macrophage activation. Genetic defects specific for cytotoxic T lymphocytes (CTL) and natural killer (NK) cells have been identified in patients with primary HPS that are responsible for altered cell death and apoptosis induction or target killing. HPS may be secondary to malignancy, infection or autoimmune disease, and mechanisms involved are poorly understood. However, in adult-onset Still's disease, juvenile chronic arthritis and probably systemic lupus erythematosus, IL-18 might play a role in initiating macrophage activation. 10.1016/S1568-9972(03)00091-0
    Sequence analysis of the granulysin and granzyme B genes in familial hemophagocytic lymphohistiocytosis. Ericson Kim Göransdotter,Fadeel Bengt,Andersson Mats,Gudmundsson Gudmundur H,Gürgey Aytemiz,Yalman Nevin,Janka Gritta,Nordenskjöld Magnus,Henter Jan-Inge Human genetics Familial hemophagocytic lymphohistiocytosis (FHL) is an autosomal recessive disorder of immune regulation. Mutations in the gene encoding perforin were previously identified in a subset of FHL patients. The present analysis of two novel candidate genes, granzyme B and granulysin, by direct sequencing in a total of 16 FHL families, disclosed several sequence variations. However, none of these sequence variations were associated with the manifestations of FHL. These data do not support the notion that granulysin and granzyme B are candidate genes for FHL. 10.1007/s00439-002-0841-0
    Atypical features of familial hemophagocytic lymphohistiocytosis. Busiello Rosanna,Adriani Marsilio,Locatelli Franco,Galgani Mario,Fimiani Giorgia,Clementi Rita,Ursini Matilde Valeria,Racioppi Luigi,Pignata Claudio Blood Familial hemophagocytic lymphohistiocytosis (FHLH) is a rare, rapidly progressive disorder of early childhood characterized by uncontrolled activation of T cells and macrophages. Although perforin gene mutations have been described in a proportion of patients with FHLH, the genotype/phenotype correlation is still limited. Only a few patients with late onset clinical manifestations have been reported. The biochemical and immunologic alterations in the asymptomatic phase are not well known. We report on a family in which 2 fraternal twins both homozygous for a perforin mutation previously described as causative of the disease, markedly differed in phenotypic expression of FHLH. The twins also had a second novel heterozygous mutation. Natural killer (NK) activity was severely impaired in the patient and was normal in the asymptomatic fraternal twin. Our report highlights that FHLH may present after a long disease-free interval during which biochemical or immunologic alterations may be not evident, thus implying a role for interfering factors. 10.1182/blood-2003-10-3551
    Familial haemophagocytic lymphohistiocytosis: advances in the genetic basis, diagnosis and management. Gholam C,Grigoriadou S,Gilmour K C,Gaspar H B Clinical and experimental immunology Familial haemophagocytic lymphohistiocytosis (FHL) is a rare autosomal recessive disorder of immune dysregulation associated with uncontrolled T cell and macrophage activation and hypercytokinaemia. The incidence of FHL is 0·12/100·000 children born per year, with a male to female ratio of 1:1. The disease is classified into six different types based on genetic linkage analysis and chromosomal localization; five specific genetic defects have been identified, which account for approximately 90% of all patients. Type 1 is due to an as yet unidentified gene defect located on chromosome nine. Type 2 is caused by mutations in the perforin (PRF1) gene, type 3 by mutations in the Munc-13-4 (UNC13D) gene, type 4 by mutations in the syntaxin 11 (STX11) gene and the recently described type 5 due to mutations in the gene encoding syntaxin binding protein 2 (STXBP-2). The incidence of the five types varies in different ethnic groups. The most common presenting features are pyrexia of unknown origin, pronounced hepatosplenomegaly and cytopenias. Neurological features tend to present later and are associated with poor prognosis. Absent or decreased lymphocyte cytotoxicity is the cellular hallmark of FHL. Biochemical features such as hyperferritinaemia, hypertriglyceridaemia and hypofibrinogenaemia are usually present, along with high levels of soluble interleukin 2 receptor in the blood and cerebrospinal fluid. Bone marrow aspirate may demonstrate the characteristic haemophagocytes, but initially is non-diagnostic in two-thirds of patients. Established international clinical, haematological and biochemical criteria now facilitate accurate clinical diagnosis. The disease is fatal unless a haematopoietic stem cell transplant (HSCT) is performed. The introduction of HSCT has dramatically improved the prognosis of the disease. However, the mortality of the disease is still significantly high and a number of challenges remain to be addressed. Active disease at the time of the transplant is the major significant poor prognostic factor. Delayed diagnosis, after irreversible organ damage has occurred, especially neurological damage, disease reoccurrence and pre-transplant mortality, remain a concern. 10.1111/j.1365-2249.2010.04302.x
    Interleukin-18: Biological properties and role in disease pathogenesis. Kaplanski Gilles Immunological reviews Initially described as an interferon (IFN)γ-inducing factor, interleukin (IL)-18 is indeed involved in Th1 and NK cell activation, but also in Th2, IL-17-producing γδ T cells and macrophage activation. IL-18, a member of the IL-1 family, is similar to IL-1β for being processed by caspase 1 to an 18 kDa-biologically active mature form. IL-18 binds to its specific receptor (IL-18Rα, also known as IL-1R7) forming a low affinity ligand chain. This is followed by recruitment of the IL-18Rβ chain. IL-18 then uses the same signaling pathway as IL-1 to activate NF-kB and induce inflammatory mediators such as adhesion molecules, chemokines and Fas ligand. IL-18 also binds to the circulating high affinity IL-18 binding protein (BP), such as only unbound free IL-18 is active. IL-18Rα may also bind IL-37, another member of the IL-1 family, but in association with the negative signaling chain termed IL-1R8, which transduces an anti-inflammatory signal. IL-18BP also binds IL-37 and this acts as a sink for the anti-inflammatory properties of IL-37. There is now ample evidence for a role of IL-18 in various infectious, metabolic or inflammatory diseases such as influenza virus infection, atheroma, myocardial infarction, chronic obstructive pulmonary disease, or Crohn's disease. However, IL-18 plays a very specific role in the pathogenesis of hemophagocytic syndromes (HS) also termed Macrophage Activation Syndrome. In children affected by NLRC4 gain-of-function mutations, IL-18 circulates in the range of tens of nanograms/mL. HS is treated with the IL-1 Receptor antagonist (anakinra) but also specifically with IL-18BP. Systemic juvenile idiopathic arthritis or adult-onset Still's disease are also characterized by high serum IL-18 concentrations and are treated by IL-18BP. 10.1111/imr.12616
    Case Report: Baricitinib as an Alternative in the Maintenance Therapy for Macrophage Activation Syndrome Secondary to Nodular Panniculitis. Frontiers in immunology Background:Macrophage activation syndrome (MAS) is a severe complication of autoimmune diseases with high mortality. We report the effectiveness of baricitinib as an option for the maintenance therapy in MAS secondary to nodular panniculitis. Case summary:A 24-year-old female came to our hospital with repeated fever and a skin nodule on right tibial tuberosity. Results were notable for raised serum ferritin (SF), triglycerides (TG), elevated liver function enzymes, interleukin-6 (IL-6), interferon-γ (IFN-γ), soluble interleukin-2 receptor (sIL-2R) and decreased activity of NK cells. The pathological biopsy of the subcutaneous nodules indicated nodular panniculitis. Hemophagocytic cells were found in bone marrow aspiration. She was diagnosed as MAS secondary to nodular panniculitis. With the treatment of methylprednisolone (MP) and immunoglobulin, her symptoms and laboratory data gradually improved. Nevertheless, her disease relapsed when the MP dose was tapered. Regarding the usage of JAK inhibitors in MAS, we used baricitinib (JAK1/2 inhibitor) to treat MAS and her symptom and abnormal laboratory findings returned to normal. During follow-up, though the MP dose was tapered, she was stable without a MAS recurrence. Conclusion:The case report suggested baricitinib is an option for MAS in the maintenance therapy phase and is potentially beneficial to prevent recurrence. 10.3389/fimmu.2022.914265
    The Integrated Analysis Identifies Three Critical Genes as Novel Diagnostic Biomarkers Involved in Immune Infiltration in Atherosclerosis. Frontiers in immunology Atherosclerosis (AS), a chronic inflammatory disease of the blood vessels, is the primary cause of cardiovascular disease, the leading cause of death worldwide. This study aimed to identify possible diagnostic markers for AS and determine their correlation with the infiltration of immune cells in AS. In total, 10 serum samples from AS patients and 10 samples from healthy subjects were collected. The original gene expression profiles of GSE43292 and GSE57691 were downloaded from the Gene Expression Omnibus database. Least absolute shrinkage and selection operator regression model and support vector machine recursive feature elimination analyses were carried out to identify candidate markers. The diagnostic values of the identified biomarkers were determined using receiver operating characteristic assays. The compositional patterns of the 22 types of immune cell fraction in AS were estimated using CIBERSORT. RT-PCR was performed to further determine the expression of the critical genes. This study identified 17 differentially expressed genes (DEGs) in AS samples. The identified DEGs were mainly involved in non-small cell lung carcinoma, pulmonary fibrosis, polycystic ovary syndrome, glucose intolerance, and T-cell leukemia. FHL5, IBSP, and SCRG1 have been identified as the diagnostic genes in AS. The expression of SCRG1 and FHL5 was distinctly downregulated in AS samples, and the expression of IBSP was distinctly upregulated in AS samples, which was further confirmed using our cohort by RT-PCR. Moreover, immune assays revealed that FHL5, IBSP, and SCRG1 were associated with several immune cells, such as CD8 T cells, naïve B cells, macrophage M0, activated memory CD4 T cells, and activated NK cells. Overall, future investigations into the occurrence and molecular mechanisms of AS may benefit from using the genes FHL5, IBSP, and SCRG1 as diagnostic markers for the condition. 10.3389/fimmu.2022.905921
    Macrophage activation-like syndrome: an immunological entity associated with rapid progression to death in sepsis. Kyriazopoulou Evdoxia,Leventogiannis Konstantinos,Norrby-Teglund Anna,Dimopoulos Georgios,Pantazi Aikaterini,Orfanos Stylianos E,Rovina Nikoletta,Tsangaris Iraklis,Gkavogianni Theologia,Botsa Elektra,Chassiou Eleftheria,Kotanidou Anastasia,Kontouli Christina,Chaloulis Panagiotis,Velissaris Dimitrios,Savva Athina,Cullberg Jonas-Sundén,Akinosoglou Karolina,Gogos Charalambos,Armaganidis Apostolos,Giamarellos-Bourboulis Evangelos J, BMC medicine BACKGROUND:A subanalysis of a randomized clinical trial indicated sepsis survival benefit from interleukin (IL)-1 blockade in patients with features of the macrophage activation-like syndrome (MALS). This study aimed to investigate the frequency of MALS and to develop a biomarker of diagnosis and prognosis. METHODS:Patients with infections and systemic inflammatory response syndrome were assigned to one test cohort (n = 3417) and a validation cohort (n = 1704). MALS was diagnosed for patients scoring positive either for the hemophagocytic syndrome score and/or having both hepatobiliary dysfunction and disseminated intravascular coagulation. Logistic regression analysis was used to estimate the predictive value of MALS for 10-day mortality in both cohorts. Ferritin, sCD163, IL-6, IL-10, IL-18, interferon gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α) were measured in the blood the first 24 h; ferritin measurements were repeated in 747 patients on day 3. RESULTS:The frequency of MALS was 3.7% and 4.3% in the test and the validation cohort, respectively. In both cohorts, MALS was an independent risk factor for 10-day mortality. A ferritin level above 4420 ng/ml was accompanied by 66.7% and 66% mortality after 28 days, respectively. Ferritin levels above 4420 ng/ml were associated with an increase of IL-6, IL-18, INF-γ, and sCD163 and a decreased IL-10/TNF-α ratio, indicating predominance of pro-inflammatory phenomena. Any less than 15% decrease of ferritin on day 3 was associated with more than 90% sensitivity for unfavorable outcome after 10 days. This high mortality risk was also validated in an independent Swedish cohort (n = 109). CONCLUSIONS:MALS is an independent life-threatening entity in sepsis. Ferritin measurements can provide early diagnosis of MALS and may allow for specific treatment. 10.1186/s12916-017-0930-5
    A novel immunoregulatory role for NK-cell cytotoxicity in protection from HLH-like immunopathology in mice. Sepulveda Fernando E,Maschalidi Sophia,Vosshenrich Christian A J,Garrigue Alexandrine,Kurowska Mathieu,Ménasche Gael,Fischer Alain,Di Santo James P,de Saint Basile Geneviève Blood The impairment of cytotoxic activity of lymphocytes disturbs immune surveillance and leads to the development of hemophagocytic lymphohistiocytic syndrome (HLH). Although cytotoxic T lymphocyte (CTL) control of HLH development is well documented, the role for natural killer (NK)-cell effector functions in the pathogenesis of this immune disorder remains unclear. In this study, we specifically targeted a defect in cytotoxicity to either CTL or NK cells in mice so as to dissect the contribution of these lymphocyte subsets to HLH-like disease severity after lymphocytic choriomeningitis virus (LCMV) infection. We found that NK-cell cytotoxicity was sufficient to protect mice from the fatal outcome that characterizes HLH-like disease and was also sufficient to reduce HLH-like manifestations. Mechanistically, NK-cell cytotoxicity reduced tissue infiltration by inflammatory macrophages and downmodulated LCMV-specific T-cell responses by limiting hyperactivation of CTL. Interestingly, the critical protective effect of NK cells on HLH was independent of interferon-γ secretion and changes in viral load. Therefore our findings identify a crucial role of NK-cell cytotoxicity in limiting HLH-like immunopathology, highlighting the important role of NK cytotoxic activity in immune homeostasis. 10.1182/blood-2014-09-602946
    Cytokine release syndrome and neurotoxicity following CAR T-cell therapy for hematologic malignancies. Freyer Craig W,Porter David L The Journal of allergy and clinical immunology Chimeric antigen receptor T cells are a new and exciting immunotherapeutic approach to managing cancer, with impressive efficacy but potentially life-threatening inflammatory toxicities such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Patients with severe CRS may develop capillary leak syndrome and disseminated intravascular coagulation, with a cytokine signature similar to that of macrophage activation syndrome/hemophagocytic lymphohistiocytosis. Moderate-to-severe CRS is managed with the IL-6 receptor antagonist tocilizumab with or without corticosteroids, with questions remaining regarding the optimal management of nonresponders. ICANS is an inflammatory neurotoxicity typically occurring after CRS and characterized by impaired blood-brain barrier integrity. Symptoms of encephalopathy range from mild confusion and aphasia to somnolence, obtundation, and in some cases seizures and cerebral edema. ICANS is currently managed with corticosteroids; however, the optimal dose and duration remain to be determined. Little information is available to guide the management of patients with steroid-refractory ICANS. Numerous cytokine-targeted therapies have been proposed to manage these inflammatory toxicities, but few clinical data are available. Management of inflammatory toxicities of chimeric antigen receptor T cells often requires multidisciplinary management and intensive care, during which allergists and immunologists may encounter patients with these unique toxicities. 10.1016/j.jaci.2020.07.025
    Advances in understanding the pathogenesis of HLH. Usmani G Naheed,Woda Bruce A,Newburger Peter E British journal of haematology Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory disorder resulting from immune dysfunction reflecting either primary immune deficiency or acquired failure of normal immune homeostasis. Familial HLH includes autosomal recessive and X-linked disorders characterized by uncontrolled activation of T cells and macrophages and overproduction of inflammatory cytokines, secondary to defects in genes encoding proteins involved in granule-dependent cytolytic pathways. In older children and adults, HLH is associated more often with infections, malignancies, autoimmune diseases, and acquired immune deficiencies. HLH, macrophage activation syndrome, sepsis, and systemic inflammatory response syndrome are different clinical entities that probably represent a common immunopathological state, termed cytokine storm. These conditions may be clinically indistinguishable; all include massive inflammatory response, elevated serum cytokine levels, multi-organ involvement, haemophagocytic macrophages, and often death. Tissues of haematopoietic and lymphoid function are directly involved; other organs are secondarily damaged by circulating cytokines and chemokines. Haemophagocytic disorders are now increasingly diagnosed in the context of severe inflammatory reactions to viruses, malignancies and systemic connective tissue diseases. Many of these cases may reflect underlying genetic predispositions to HLH. The detection of gene defects has contributed considerably to our understanding of HLH, but the mechanisms leading to acquired HLH have yet to be fully determined. 10.1111/bjh.12293
    Alleviating the storm: ruxolitinib in HLH. La Rosée Paul Blood In this issue of Blood, Das and colleagues report their results on the use of the Janus kinase 1/2 (JAK1/2) inhibitor ruxolitinib in murine models of hemophagocytic lymphohistiocytosis (HLH), and the HLH-sibling macrophage activation syndrome (MAS). 10.1182/blood-2016-02-697151
    An inframe perforin gene deletion in familial hemophagocytic lymphohistiocytosis is associated with perforin expression. Muralitharan Shanmugakonar,Al Lamki Zakia,Dennison David,Christie Brian Sidney,Wali Yasser A,Zachariah Mathew,Romana Marc,Bayoumi Riad,Krishnamoorthy Rajagopal American journal of hematology Familial hemophagocytic lymphohistiocytosis is an autosomal recessive disease of early childhood manifested by hypercytokinemia and organ infiltration of macrophages and activated lymphocytes, and it is characterized by a fulminant clinical course. The molecular mechanism underlying this disease appears to be a deregulation of apoptosis of activated T cells and macrophages. Approximately 20-40% of patients with familial hemophagocytic lymphohistiocytosis reported worldwide had a perforin gene mutation. We report herein a novel perforin variant in the homozygous state in an Omani boy who was diagnosed 44 days after birth. Sequence analysis of the perforin gene coding region revealed a 12-base pair deletion (codon 284-287) resulting in the deletion of four amino acids in the membrane attack complex domain of the protein. This deletion maintains the reading frame of the perforin mRNA. Both parents were heterozygotes for this molecular defect. Flow-cytometric analysis revealed intracellular perforin expression at the lower end of the normal range in the cytotoxic T cells (CD3+/CD8+) and (CD3+/CD56+) and in around 50% of the natural killer cells (CD3-/CD56+). This is an additional example of a perforin variant which is associated with a significant level of cellular perforin expression and thus confirms that drastic reduction in its expression is not a constant feature in familial hemophagocytic lymphohistiocytosis type 2. 10.1002/ajh.20256
    Revised classification of histiocytoses and neoplasms of the macrophage-dendritic cell lineages. Emile Jean-François,Abla Oussama,Fraitag Sylvie,Horne Annacarin,Haroche Julien,Donadieu Jean,Requena-Caballero Luis,Jordan Michael B,Abdel-Wahab Omar,Allen Carl E,Charlotte Frédéric,Diamond Eli L,Egeler R Maarten,Fischer Alain,Herrera Juana Gil,Henter Jan-Inge,Janku Filip,Merad Miriam,Picarsic Jennifer,Rodriguez-Galindo Carlos,Rollins Barret J,Tazi Abdellatif,Vassallo Robert,Weiss Lawrence M, Blood The histiocytoses are rare disorders characterized by the accumulation of macrophage, dendritic cell, or monocyte-derived cells in various tissues and organs of children and adults. More than 100 different subtypes have been described, with a wide range of clinical manifestations, presentations, and histologies. Since the first classification in 1987, a number of new findings regarding the cellular origins, molecular pathology, and clinical features of histiocytic disorders have been identified. We propose herein a revision of the classification of histiocytoses based on histology, phenotype, molecular alterations, and clinical and imaging characteristics. This revised classification system consists of 5 groups of diseases: (1) Langerhans-related, (2) cutaneous and mucocutaneous, and (3) malignant histiocytoses as well as (4) Rosai-Dorfman disease and (5) hemophagocytic lymphohistiocytosis and macrophage activation syndrome. Herein, we provide guidelines and recommendations for diagnoses of these disorders. 10.1182/blood-2016-01-690636
    Reactions Related to CAR-T Cell Therapy. Miao Lele,Zhang Zhengchao,Ren Zhijian,Li Yumin Frontiers in immunology The application of chimeric antigen receptor (CAR) T-cell therapy as a tumor immunotherapy has received great interest in recent years. This therapeutic approach has been used to treat hematological malignancies solid tumors. However, it is associated with adverse reactions such as, cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), off-target effects, anaphylaxis, infections associated with CAR-T-cell infusion (CTI), tumor lysis syndrome (TLS), B-cell dysplasia, hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) and coagulation disorders. These adverse reactions can be life-threatening, and thus they should be identified early and treated effectively. In this paper, we review the adverse reactions associated with CAR-T cells, the mechanisms driving such adverse reactions, and strategies to subvert them. This review will provide important reference data to guide clinical application of CAR-T cell therapy. 10.3389/fimmu.2021.663201
    Brief Report: Novel UNC13D Intronic Variant Disrupting an NF-κB Enhancer in a Patient With Recurrent Macrophage Activation Syndrome and Systemic Juvenile Idiopathic Arthritis. Schulert Grant S,Zhang Mingce,Husami Ammar,Fall Ndate,Brunner Hermine,Zhang Kejian,Cron Randy Q,Grom Alexei A Arthritis & rheumatology (Hoboken, N.J.) OBJECTIVE:Macrophage activation syndrome (MAS) is a life-threatening complication of systemic juvenile idiopathic arthritis (JIA) and has pathologic similarity to hemophagocytic lymphohistiocytosis (HLH). Intronic variants in UNC13D are found in patients with familial HLH type 3 (FHLH3), but the role of noncoding variants in MAS is unknown. The objective of this study was to identify deep intronic UNC13D variants in patients with MAS. METHODS:A custom enrichment library was constructed to sequence a genomic region of ~1 Mb flanking UNC13D in 24 patients with systemic JIA, recurrent MAS, and negative results of prior genetic (exon/coding) testing. The functional consequences of intronic variants were assessed using quantitative polymerase chain reaction in patient-derived peripheral blood mononuclear cells (PBMCs), electromobility shift assay, in vitro transcriptional enhancer assays, and natural killer (NK) cell degranulation assays. RESULTS:We evaluated a patient with systemic JIA and recurrent MAS in whom a novel functional intronic variant in UNC13D, c.117+143A>G, was observed. This variant occurred in a proposed regulatory region that drives lymphocyte-specific UNC13D expression and is associated with reduced transcript levels in patient PBMCs. This variant also disrupted NF-κB binding to a functional transcriptional enhancer, leading to reduced enhancer activity in vitro. Partial knockdown of UNC13D expression also led to impaired NK cell degranulation. An additional patient was identified with a previously described UNC13D intronic variant, for a total noncoding variant hit rate of 8.3% (2 of 24). CONCLUSION:These findings highlight the notion that intronic variants in key regulatory regions may be associated with MAS in patients with systemic JIA and support deep sequencing approaches when causative coding variants are not identified. 10.1002/art.40438
    Repeated TLR9 stimulation results in macrophage activation syndrome-like disease in mice. Behrens Edward M,Canna Scott W,Slade Katharine,Rao Sheila,Kreiger Portia A,Paessler Michele,Kambayashi Taku,Koretzky Gary A The Journal of clinical investigation Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are 2 similar diseases characterized by a cytokine storm, overwhelming inflammation, multiorgan dysfunction, and death. Animal models of HLH suggest that disease is driven by IFN-γ produced by CD8⁺ lymphocytes stimulated by persistent antigen exposure. In these models and patients with "primary" HLH, the antigen persists due to genetic defects, resulting in ineffective cytotoxic responses by CD8⁺ T cells and poor pathogen clearance. However, infectious triggers are often not identified in patients with MAS, and some patients with HLH or MAS lack defects in cytotoxic T cell killing. Herein, we show that repeated stimulation of TLR9 produced an HLH/MAS-like syndrome on a normal genetic background, without exogenous antigen. Like previous HLH models, TLR9-induced MAS was IFN-γ dependent; however, unlike other models, disease did not require lymphocytes. We further showed that IL-10 played a protective role in this model and that blocking IL-10 signaling led to the development of hemophagocytosis. IL-10 may therefore be an important target for the development of effective therapeutics for MAS. Our data provide insight into MAS-like syndromes in patients with inflammatory diseases in which there is chronic innate immune activation but no genetic defects in cytotoxic cell function. 10.1172/JCI43157
    Paediatric rheumatic disease: Diagnosing macrophage activation syndrome in systemic JIA. Vastert Sebastiaan J,Prakken Berent J Nature reviews. Rheumatology Macrophage activation syndrome (MAS) in systemic juvenile idiopathic arthritis (sJIA) is difficult to distinguish from active sJIA or sepsis. A collaborative effort scoring the performance of different clinical diagnostic criteria provides valuable guidance to clinicians, but challenges in the diagnosis of sJIA-related MAS remain. 10.1038/nrrheum.2014.143
    Systemic juvenile idiopathic arthritis and macrophage activation syndrome: update on pathogenesis and treatment. Yasin Shima,Schulert Grant S Current opinion in rheumatology PURPOSE OF REVIEW:The past decade has seen substantial progress in defining the cause and pathogenesis of the chronic childhood arthropathy systemic juvenile idiopathic arthritis (SJIA) and its related complication macrophage activation syndrome (MAS). The purpose of this review is to describe and synthesize advances in this field, particularly since 2016, with the potential to transform clinical practice. RECENT FINDINGS:Newly developed MAS classification criteria have been further studied and validated in other diseases and populations, as well as a recently proposed score to distinguish MAS from familial hemophagocytic lymphohistiocytosis. There has also been substantial progress toward understanding the genetic underpinnings of SJIA and MAS, both through targeted study of specific genes and the results of a large genome-wide association study. The immunopathogenesis of SJIA has been further elucidated through several studies regarding the proinflammatory cytokines interleukin-18, interferon (IFN)γ, and how their interplay impacts emergence of MAS. Finally, big data studies integrating genomic information with immunophenotypes have potential to provide novel insights into disease mechanisms in SJIA. SUMMARY:Collectively, these research advances have significant implications regarding the classification and diagnosis of SJIA and MAS, and support a next generation of biologic treatments including kinase inhibitors and targeted interleukin-18 or IFNγ blockade. 10.1097/BOR.0000000000000526
    Inherited defects in lymphocyte cytotoxic activity. Pachlopnik Schmid Jana,Schmid Jana P,Côte Marjorie,Ménager Mickaël M,Burgess Agathe,Nehme Nadine,Ménasché Gaël,Fischer Alain,de Saint Basile Geneviève Immunological reviews The granule-dependent cytotoxic activity of lymphocytes plays a critical role in the defense against virally infected cells and tumor cells. The importance of this cytotoxic pathway in immune regulation is evidenced by the severe and often fatal condition, known as hemophagocytic lymphohistiocytic syndrome (HLH) that occurs in mice and humans with genetically determined impaired lymphocyte cytotoxic function. HLH manifests as the occurrence of uncontrolled activation of T lymphocytes and macrophages infiltrating multiple organs. In this review, we focus on recent advances in the characterization of effectors regulating the release of cytotoxic granules, and on the role of this cytotoxic pathway in lymphocyte homeostasis and immune surveillance. Analysis of the mechanisms leading to the occurrence of hemophagocytic syndrome designates gamma-interferon as an attractive therapeutic target to downregulate uncontrolled macrophage activation, which sustains clinical and biological features of HLH. 10.1111/j.0105-2896.2010.00890.x
    Distinct cytokine profile in juvenile systemic lupus erythematosus-associated macrophage activation syndrome. Shimizu Masaki,Yokoyama Tadafumi,Tokuhisa Yuko,Ishikawa Sayaka,Sakakibara Yasuhisa,Ueno Kazuyuki,Yachie Akihiro Clinical immunology (Orlando, Fla.) Macrophage activation syndrome (MAS) has been observed in patients with systemic lupus erythematosus (SLE). Recognition of MAS in patients with SLE may be particularly challenging because it may mimic the clinical features of the underlying disease or be confused with an infectious complication. Massive hypercytokinemia is strongly associated with the pathogenesis of systemic lupus erythematosus-associated macrophage activation syndrome (SLE-MAS) but the pathogenesis and kinetics of cytokine release in SLE-MAS patients is not well studied. We present a case of SLE-MAS. The patient showed the distinct cytokine profile of SLE-MAS compared to systemic juvenile idiopathic arthritis associated MAS and Epstein-Barr virus-induced hemophagocytic lymphohistiocytosis. The observed TNF-α dominant increase appears to be characteristic of SLE-MAS. IgM type antilymphocyte antibody (ALAB) was detected on the surface of lymphocytes during the acute phase and disappeared when the patient was in remission. The patient had a heterozygous P369S-R408Q mutation in the MEFV gene. Our results suggest that ALAB and a MEFV mutation might play important roles in the pathogenesis of SLE-MAS. Furthermore, the cytokine profile of SLE-MAS differs from that of S-JIA-MAS: the TNF-α dominant increase appears to be characteristic. 10.1016/j.clim.2012.11.004
    Natural Killer Cells in Systemic Autoinflammatory Diseases: A Focus on Systemic Juvenile Idiopathic Arthritis and Macrophage Activation Syndrome. Vandenhaute Jessica,Wouters Carine H,Matthys Patrick Frontiers in immunology Natural killer (NK) cells are innate immune lymphocytes with potent cytolytic and immune-regulatory activities. NK cells are well-known for their ability to kill infected and malignant cells in a fast and non-specific way without prior sensitization. For this purpose, NK cells are equipped with a set of cytotoxic molecules such as perforin and apoptosis-inducing proteins. NK cells also have the capacity to produce large amounts of cytokines and chemokines that synergize with their cytotoxic function and that ensure interaction with other immune cells. A less known feature of NK cells is their capacity to kill non-infected autologous cells, such as immature dendritic cells and activated T cells and monocytes. Via the release of large amounts of TNF-α and IFN-γ, NK cells may contribute to disease pathology. Conversely they may exert a regulatory role through secretion of immuno-regulatory cytokines such as GM-CSF, IL-13, and IL-10. Thus, NK cells may be important target and effector cells in the pathogenesis of autoinflammatory diseases, in particular in those disorders associated with a cytokine storm or in conditions where immune cells are highly activated. Key examples of such diseases are systemic juvenile idiopathic arthritis (sJIA) and its well-associated complication, macrophage activation syndrome (MAS). sJIA is a chronic childhood immune disorder of unknown etiology, characterized by arthritis and systemic inflammation, including a daily spiking fever and evanescent rash. MAS is a potentially fatal complication of autoimmune and autoinflammatory diseases, and most prevalently associated with sJIA. MAS is considered as a subtype of hemophagocytic lymphohistiocytosis (HLH), a systemic hyperinflammatory disorder characterized by defective cytotoxic pathways of cytotoxic T and NK cells. In this review, we describe the established features of NK cells and provide the results of a literature survey on the reported NK cell abnormalities in monogenic and multifactorial autoinflammatory disorders. Finally, we discuss the role of NK cells in the pathogenesis of sJIA and MAS. 10.3389/fimmu.2019.03089
    Highways to hell: Mechanism-based management of cytokine storm syndromes. Canna Scott W,Cron Randy Q The Journal of allergy and clinical immunology Since the first textbook devoted to cytokine storm syndromes (CSSs) was published in 2019, the world has changed dramatically and the term's visibility has broadened. Herein, we define CSSs broadly to include life/organ-threatening systemic inflammation and immunopathology regardless of the context in which it occurs, recognizing that the indistinct borders of such a definition limit its utility. Nevertheless, we are focused on the pathomechanisms leading to CSSs, including impairment of granule-mediated cytotoxicity, specific viral infections, excess IL-18, and chimeric antigen receptor T-cell therapy. These mechanisms are often reflected in distinct clinical features, functional tests, and/or biomarker assessments. Moreover, these mechanisms often indicate specific, definitive treatments. This mechanism-focused organization is vital to both advancing the field and understanding the complexities in individual patients. However, increasing evidence suggests that these mechanisms interact and overlap. Likewise, the utility of a broad term such as "cytokine storm" is that it reflects a convergence on a systemic inflammatory phenotype that, regardless of cause or context, may be amenable to "inflammo-stabilization." CSS research must improve our appreciation of its various mechanisms and their interactions and treatments, but it must also identify the signs and interventions that may broadly prevent CSS-induced immunopathology. 10.1016/j.jaci.2020.09.016
    Macrophage activation syndrome in adults: recent advances in pathophysiology, diagnosis and treatment. Carter Stuart J,Tattersall Rachel S,Ramanan Athimalaipet V Rheumatology (Oxford, England) Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome, which if not promptly treated, can lead rapidly to critical illness and death. HLH is termed macrophage activation syndrome (MAS) when associated with rheumatic disease (where it is best characterized in systemic JIA) and secondary HLH (sHLH) when associated with other triggers including malignancy and infection. MAS/sHLH is rare and coupled with its mimicry of other conditions, is underrecognized. These inherent challenges can lead to diagnostic and management challenges in multiple medical specialties including haematology, infectious diseases, critical care and rheumatology. In this review we highlight the pathogenesis of MAS/sHLH including its underlying triggers, key clinical features and diagnostic challenges, prognostic factors and current treatments in adults. 10.1093/rheumatology/key006
    Macrophage activation syndrome in the era of biologic therapy. Grom Alexei A,Horne AnnaCarin,De Benedetti Fabrizio Nature reviews. Rheumatology Macrophage activation syndrome (MAS) refers to acute overwhelming inflammation caused by a 'cytokine storm'. Although increasingly recognized as a life-threatening complication of various rheumatic diseases, clinically, MAS is strikingly similar to primary and secondary forms of haemophagocytic lymphohistiocytosis (HLH). Not surprisingly, many rheumatologists prefer the term secondary HLH rather than MAS to describe this condition, and efforts to change the nomenclature are in progress. The pathophysiology of MAS remains elusive, but observations in animal models, as well as data on the effects of new anticytokine therapies on rates and clinical presentations of MAS in patients with systemic juvenile idiopathic arthritis (sJIA), provide clues to the understanding of this perplexing clinical phenomenon. In this Review, we explore the latest available evidence and discuss potential diagnostic challenges in the era of increasing use of biologic therapies. 10.1038/nrrheum.2015.179
    Haemophagocytic lymphohistiocytosis in adults: a multicentre case series over 7 years. Schram Alison M,Comstock Paige,Campo Meghan,Gorovets Daniel,Mullally Ann,Bodio Kelly,Arnason Jon,Berliner Nancy British journal of haematology Haemophagocytic lymphohistiocytosis (HLH) is a syndrome of uncontrolled immune activation that has gained increasing attention over the past decade. Although classically known as a familial disorder of children caused by mutations that affect cytotoxic T-cell function, an acquired form of HLH in adults is now widely recognized. This is often seen in the setting of malignancy, infection or rheumatological disorders. We performed a retrospective review across 3 tertiary care centres and identified 68 adults with HLH. The average age was 53 years (range 18-77 years) and 43 were male (63%). Underlying disorders included malignancy in 33 patients (49%), infection in 22 (33%), autoimmune disease in 19 (28%) and idiopathic HLH in 15 (22%). Patients were treated with disease-specific therapy and immunomodulatory agents. After a median follow-up of 32·2 months, 46 patients had died (69%). The median overall survival was 4 months (95% CI: 0·0-10·2 months). Patients with malignancy had a worse prognosis compared to those without (median survival 2·8 months versus 10·7 months, P = 0·007). HLH is a devastating disorder with a high mortality. Further research is needed to improve treatment and outcomes. 10.1111/bjh.13837
    Novel spectrum of perforin gene mutations in familial hemophagocytic lymphohistiocytosis in ethnic Omani patients. Muralitharan Shanmugakonar,Wali Yasser A,Dennison David,Lamki Zakia A,Zachariah Mathew,Nagwa El Banna,Pathare Anil,Krishnamoorthy Rajagopal American journal of hematology Familial hemophagocytic lymphohistiocytosis (FHL) is an autosomal recessive immune disorder, characterized by fever, hepatosplenomegaly, pancytopenia, hypertriglyceridemia, hypofibrinogenemia, markedly elevated levels of inflammatory cytokines, and impaired cytotoxic activity of lymphocytes. FHL is often fatal in early infancy. Histologic features include organ infiltration by activated macrophages and lymphocytes. Four genetic loci (FHL1, 2, 3, and 4) have been identified, of which FHL2 involves mutations in the perforin gene and is present in 20-50% of patients with FHL. We herein report the first comprehensive molecular analysis of 16 unrelated cases of FHL in ethnic Omanis. Using direct DNA sequencing analysis in 11 families, seven different mutations were identified in the coding region of the perforin gene, of which five were novel. Perforin gene defects do not seem to be involved in one-third of the cases of FHL in ethnic Omanis. 10.1002/ajh.21009
    Pathogenesis of macrophage activation syndrome and potential for cytokine- directed therapies. Schulert Grant S,Grom Alexei A Annual review of medicine Macrophage activation syndrome (MAS) is an acute episode of overwhelming inflammation characterized by activation and expansion of T lymphocytes and hemophagocytic macrophages. In rheumatology, it occurs most frequently in patients with systemic juvenile idiopathic arthritis (SJIA) and systemic lupus erythematosus. The main clinical manifestations include cytopenias, liver dysfunction, coagulopathy resembling disseminated intravascular coagulation, and extreme hyperferritinemia. Clinically and pathologically, MAS bears strong similarity to hemophagocytic lymphohistiocytosis (HLH), and some authors prefer the term secondary HLH to describe it. Central to its pathogenesis is a cytokine storm, with markedly increased levels of numerous proinflammatory cytokines including IL-1, IL-6, IL-18, TNFα, and IFNγ. Although there is evidence that IFNγ may play a central role in the pathogenesis of MAS, the role of other cytokines is still not clear. There are several reports of SJIA-associated MAS dramatically benefiting from anakinra, a recombinant IL-1 receptor antagonist, but the utility of other biologics in MAS is not clear. The mainstay of treatment remains corticosteroids; other medications, including cyclosporine, are used in patients who fail to respond. 10.1146/annurev-med-061813-012806
    Histiocytosis and Neoplasms of Macrophage-Dendritic Cell Lineages: Multimodality Imaging with Emphasis on PET/CT. Huynh Kenneth N,Nguyen Ba D Radiographics : a review publication of the Radiological Society of North America, Inc Histiocytosis is a rare inflammatory process characterized by pathologic infiltration and accumulation of cells derived from the monocytic lineage in normal tissue. It encompasses more than 100 different subtypes of disorders that were recently classified into five main groups: Langerhans-related histiocytosis, Rosai-Dorfman histiocytosis, cutaneous and mucocutaneous histiocytosis, malignant histiocytosis, and hemophagocytic lymphohistiocytosis and macrophage activation syndrome. Langerhans cell histiocytosis is the most common histiocytic disorder. Less common types include Erdheim-Chester disease, Rosai-Dorfman disease, adult and juvenile xanthogranuloma, necrobiotic xanthogranuloma, histiocytic sarcoma, interdigitating dendritic cell sarcoma, Langerhans cell sarcoma, and hemophagocytic lymphohistiocytosis. Although the pathogenesis of these disorders may be attributable to mutations in the oncogenic driver, recent discoveries have shown that inflammation and fibrosis secondary to mutated histiocytes, rather than a proliferative cell mechanism, result in manifestation of the disease. Diagnosis, which relies on a multidisciplinary approach, is challenging and often delayed because clinical findings are nonspecific and may mimic malignant processes at radiologic evaluation. Compared with conventional imaging, PET/CT allows detection of the increased metabolic activity in histiocytes. Diagnostic algorithms for histiocytic disorders should include functional imaging with fluorine 18 (F) fluorodeoxyglucose (FDG) PET/CT, which provides a comprehensive whole-body evaluation of their potential involvement with multiple organ systems and allows monitoring of therapeutic response. The most recent revised classification, pathophysiologic and clinical manifestations, sites of involvement, and imaging features of histiocytosis are described in this review and a multimodality approach is used, with emphasis on F-FDG PET/CT evaluation. RSNA, 2021. 10.1148/rg.2021200096
    Macrophage Activation Syndrome. Sen Ethan S,Clarke Sarah L N,Ramanan Athimalaipet V Indian journal of pediatrics Macrophage activation syndrome (MAS) is a potentially life-threatening complication of rheumatic diseases such as systemic juvenile idiopathic arthritis (sJIA) and systemic lupus erythematosus. It is often considered a type of secondary hemophagocytic lymphohistiocytosis (HLH) and results from over-activation of T lymphocytes and macrophages leading to a "cytokine storm". Characteristic features are persistent fever, lymphadenopathy, hepatosplenomegaly, cytopenias (anemia, leucopenia, thrombocytopenia), raised C-reactive protein, falling erythrocyte sedimentation rate, hypofibrinogenemia, transaminitis, hypertriglyceridemia and extreme hyperferritinemia often associated with multi-organ impairment. Key to its management is early recognition of MAS which may be difficult due to similarity to systemic sepsis or flares of the underlying rheumatic disease. To aid with this process, criteria for the diagnosis of MAS in patients with sJIA derived by international consensus have been published. Although bone marrow biopsy showing hemophagocytosis is strongly supportive it is not essential for diagnosis. Together with appropriate supportive care, first-line treatment is high-dose intravenous corticosteroids with cyclosporin or intravenous immunoglobulin (IVIg) added if there is not initial response. Although etoposide is used by hematologists in treatment of HLH, there are concerns regarding organ toxicity and bone marrow suppression which weigh against its use in initial management of MAS. With increasing understanding of the pathogenesis of MAS, use of drugs targeting specific cytokines has been reported in case series. The relatively rapid effectiveness of anakinra, a recombinant IL-1 receptor antagonist, has been documented. Further studies of this and other biologic agents are required to identify the most effective and safest treatment option for refractory MAS. 10.1007/s12098-015-1877-1
    Macrophage activation syndrome in children with Kawasaki disease: diagnostic and therapeutic approaches. Han Seung Beom,Lee Soo-Young World journal of pediatrics : WJP BACKGROUND:Macrophage activation syndrome (MAS) is a rare, life-threatening complication of Kawasaki disease (KD). Early recognition and treatment of MAS are very important, but sometimes it is difficult to distinguish MAS from a severe form of KD. DATA SOURCES:A PubMed search was performed in Clinical Queries using the key terms "macrophage activation syndrome or secondary hemophagocytic lymphohistiocytosis (HLH)" and "Kawasaki disease". RESULTS:KD patients with MAS show high intravenous immunoglobulin (IVIG) resistance and coronary complications. Mortality is also as high as MAS in other diseases. Persistent fever greater than 10 days is highly associated with development of MAS in KD. Splenomegaly is observed in more than two-thirds of KD patients with MAS. Thrombocytopenia is often the earliest laboratory finding of MAS. Hyperferritinemia is highly specific and sensitive for detecting MAS in KD; so, ferritin levels should be checked if there are unexplained clinical exacerbations in KD patients. Given the under-recognition of MAS in KD, it is prudent to consider resistant KD as occult/subclinical MAS. Many KD patients with MAS have good outcomes on immune modulators. However, if KD patients fulfill the HLH-2004 diagnostic criteria, they may undergo longer and more intensive treatment than needed. CONCLUSIONS:The possible existence of MAS should be taken into account when a KD patient shows persistent fever, splenomegaly, thrombocytopenia, hyperferritinemia, or IVIG resistance. The under-diagnosis of MAS in patients with KD is an important issue to be addressed. Therapeutically, however, there is a possibility of over-treatment of MAS in patients with KD. 10.1007/s12519-020-00360-6
    Cytokine release syndrome after blinatumomab treatment related to abnormal macrophage activation and ameliorated with cytokine-directed therapy. Teachey David T,Rheingold Susan R,Maude Shannon L,Zugmaier Gerhard,Barrett David M,Seif Alix E,Nichols Kim E,Suppa Erica K,Kalos Michael,Berg Robert A,Fitzgerald Julie C,Aplenc Richard,Gore Lia,Grupp Stephan A Blood Blinatumomab is a CD19/CD3-bispecific T-cell receptor-engaging (BiTE) antibody with efficacy in refractory B-precursor acute lymphoblastic leukemia. Some patients treated with blinatumomab and other T cell-activating therapies develop cytokine release syndrome (CRS). We hypothesized that patients with more severe toxicity may experience abnormal macrophage activation triggered by the release of cytokines by T-cell receptor-activated cytotoxic T cells engaged by BiTE antibodies and leading to hemophagocytic lymphohistiocytosis (HLH). We prospectively monitored a patient during blinatumomab treatment and observed that he developed HLH. He became ill 36 hours into the infusion with fever, respiratory failure, and circulatory collapse. He developed hyperferritinemia, cytopenias, hypofibrinogenemia, and a cytokine profile diagnostic for HLH. The HLH continued to progress after discontinuation of blinatumomab; however, he had rapid improvement after IL-6 receptor-directed therapy with tocilizumab. Patients treated with T cell-activating therapies, including blinatumomab, should be monitored for HLH, and cytokine-directed therapy may be considered in cases of life-threatening CRS. This trial was registered at www.clinicaltrials.gov as #NCT00103285. 10.1182/blood-2013-02-485623
    Immune-mediated inflammatory diseases with chronic excess of serum interleukin-18. Frontiers in immunology : Interleukin-18 (IL-18) is a proinflammatory cytokine that promotes various innate immune processes related to infection, inflammation, and autoimmunity. Patients with systemic juvenile idiopathic arthritis and adult-onset Still's disease exhibit chronic excess of serum IL-18, which is associated with a high incidence of macrophage activation syndrome (MAS), although the mechanisms of IL-18 regulation in such diseases remain largely unknown. Similar elevation of serum IL-18 and susceptibility to MAS/hemophagocytic lymphohistiocytosis (HLH) have been reported in monogenic diseases such as X-linked inhibitor of apoptosis deficiency (i.e., X-linked lymphoproliferative syndrome type 2) and NLRC4-associated autoinflammatory disease. Recent advances in molecular and cellular biology allow the identification of other genetic defects such as defects in , , and that result in high serum IL-18 levels and hyperinflammation. Among these diseases, chronic excess of serum IL-18 appears to be linked with severe hyperinflammation and/or predisposition to MAS/HLH. In this review, we focus on recent findings in inflammatory diseases associated with and probably attributable to chronic excess of serum IL-18 and describe the clinical and therapeutical relevance of understanding the pathology of this group of diseases. 10.3389/fimmu.2022.930141
    Advances in the pathogenesis of primary and secondary haemophagocytic lymphohistiocytosis: differences and similarities. Brisse Ellen,Wouters Carine H,Matthys Patrick British journal of haematology Haemophagocytic lymphohistiocytosis (HLH) comprises a heterogeneous spectrum of hyperinflammatory conditions that are inherited (primary HLH) or acquired in a context of infections, malignancies or autoimmune/autoinflammatory disorders (secondary HLH). Genetic defects in the cytotoxic machinery of natural killer and CD8(+) T cells underlie primary HLH, with residual cytotoxicity determining disease severity. Improved sequencing techniques have expanded the range of causal mutations and have redefined many cases of secondary HLH as primary HLH and vice versa, blurring the distinction between both subtypes. These insights allow HLH to be conceptualized as a threshold disease, in which interplay between various genetic and environmental factors causes progressive inflammation into a critical point, beyond which uncontrolled activation of immune cells and excessive cytokine production give rise to the cardinal symptoms of HLH. Various pathogenic pathways may thus converge to a common end stage of fulminant HLH. 10.1111/bjh.14147
    Perforin-deficient CAR T cells recapitulate late-onset inflammatory toxicities observed in patients. Ishii Kazusa,Pouzolles Marie,Chien Christopher D,Erwin-Cohen Rebecca A,Kohler M Eric,Qin Haiying,Lei Haiyan,Kuhn Skyler,Ombrello Amanda K,Dulau-Florea Alina,Eckhaus Michael A,Shalabi Haneen,Yates Bonnie,Lichtenstein Daniel A,Zimmermann Valérie S,Kondo Taisuke,Shern Jack F,Young Howard A,Taylor Naomi,Shah Nirali N,Fry Terry J The Journal of clinical investigation Late-onset inflammatory toxicities resembling hemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome (MAS) occur after chimeric antigen receptor T cell (CAR T cell) infusion and represent a therapeutic challenge. Given the established link between perforin deficiency and primary HLH, we investigated the role of perforin in anti-CD19 CAR T cell efficacy and HLH-like toxicities in a syngeneic murine model. Perforin contributed to both CD8+ and CD4+ CAR T cell cytotoxicity but was not required for in vitro or in vivo leukemia clearance. Upon CAR-mediated in vitro activation, perforin-deficient CAR T cells produced higher amounts of proinflammatory cytokines compared with WT CAR T cells. Following in vivo clearance of leukemia, perforin-deficient CAR T cells reexpanded, resulting in splenomegaly with disruption of normal splenic architecture and the presence of hemophagocytes, which are findings reminiscent of HLH. Notably, a substantial fraction of patients who received anti-CD22 CAR T cells also experienced biphasic inflammation, with the second phase occurring after the resolution of cytokine release syndrome, resembling clinical manifestations of HLH. Elevated inflammatory cytokines such as IL-1β and IL-18 and concurrent late CAR T cell expansion characterized the HLH-like syndromes occurring in the murine model and in humans. Thus, a murine model of perforin-deficient CAR T cells recapitulated late-onset inflammatory toxicities occurring in human CAR T cell recipients, providing therapeutically relevant mechanistic insights. 10.1172/JCI130059
    Targeting interferon-γ in hyperinflammation: opportunities and challenges. De Benedetti Fabrizio,Prencipe Giusi,Bracaglia Claudia,Marasco Emiliano,Grom Alexei A Nature reviews. Rheumatology Interferon-γ (IFNγ) is a pleiotropic cytokine with multiple effects on the inflammatory response and on innate and adaptive immunity. Overproduction of IFNγ underlies several, potentially fatal, hyperinflammatory or immune-mediated diseases. Several data from animal models and/or from translational research in patients point to a role of IFNγ in hyperinflammatory diseases, such as primary haemophagocytic lymphohistiocytosis, various forms of secondary haemophagocytic lymphohistiocytosis, including macrophage activation syndrome, and cytokine release syndrome, all of which are often managed by rheumatologists or in consultation with rheumatologists. Given the effects of IFNγ on B cells and T follicular helper cells, a role for IFNγ in systemic lupus erythematosus pathogenesis is emerging. To improve our understanding of the role of IFNγ in human disease, IFNγ-related biomarkers that are relevant for the management of hyperinflammatory diseases are progressively being identified and studied, especially because circulating levels of IFNγ do not always reflect its overproduction in tissue. These biomarkers include STAT1 (specifically the phosphorylated form), neopterin and the chemokine CXCL9. IFNγ-neutralizing agents have shown efficacy in the treatment of primary haemophagocytic lymphohistiocytosis in clinical trials and initial promising results have been obtained in various forms of secondary haemophagocytic lymphohistiocytosis, including macrophage activation syndrome. In clinical practice, there is a growing body of evidence supporting the usefulness of circulating CXCL9 levels as a biomarker reflecting IFNγ production. 10.1038/s41584-021-00694-z
    Malignancy-associated haemophagocytic lymphohistiocytosis. The Lancet. Haematology Haemophagocytic lymphohistiocytosis (HLH) is an inflammatory syndrome that can occur with cancer (malignancy-associated HLH) or with immune-activating therapies for cancer. Patients with lymphoma appear to be at particularly high risk for malignancy-associated HLH. The familial form of HLH is characterised by uncontrolled activation of macrophages and cytotoxic T cells, which can be identified by genetics or specific immune markers. However, the pathophysiology of malignancy-associated HLH is not well understood, and distinguishing pathological immune activation from the laboratory and clinical abnormalities seen in cancer and cancer treatment is challenging. Emerging diagnostic tools, such as serum cytokine or chemokine concentrations, flow cytometry, and other functional measures, are discussed. Mortality remains high with current approaches. Targeted therapy, including blockade of specific cytokines such as IL-1, IL-6, and IFNγ, and inhibition of the JAK-STAT pathways might improve outcomes for some patients. Finally, we discuss a framework for thinking of malignancy-associated HLH within a larger umbrella concept of cytokine storm syndrome. 10.1016/S2352-3026(21)00366-5
    SLAMF3 and SLAMF4 are immune checkpoints that constrain macrophage phagocytosis of hematopoietic tumors. Li Dan,Xiong Wei,Wang Yuande,Feng Jin,He Yuexi,Du Juan,Wang Jing,Yang Meixiang,Zeng Hui,Yang Yong-Guang,Wu Ning,Chen Shasha,Dong Zhongjun Science immunology The interaction of SIRPα with CD47 represents a major mechanism for preventing macrophage phagocytosis. However, CD47-independent mechanisms are poorly defined. Here, we report a critical role of SLAM family receptors (SFRs), ubiquitously expressed on hematopoietic cells and forming homotypic interactions, in constraining macrophage phagocytosis. We found that SFR deficiency triggered macrophage phagocytosis of hematopoietic cells, leading to severe rejection of donor hematopoietic graft in recipient mice. Specific SFR members, mainly SLAMF3 and SLAMF4, were identified as "don't eat me" receptors on macrophages. These receptors inhibited "eat me" signals, such as LRP1-mediated activation of mTOR and Syk, through SH2 domain-containing phosphatases. SFRs combined with, but were independent of, CD47 to mitigate macrophage phagocytosis, and the combined deletion of SFRs and CD47 resulted in hematopoietic cytopenia in mice. This SFR-mediated tolerance was compromised in patients with hemophagocytic lymphohistiocytosis, a syndrome characterized by inappropriate phagocytosis toward hematopoietic cells. Loss of SFRs potently elicited macrophage rejection of hematopoietic tumors. Deletion of SFRs also significantly enhanced the phagocytosis of CD19-positive hematopoietic targets by the macrophages expressing the chimeric CD19 antigen receptor. Therefore, SFR-mediated inhibition of macrophage phagocytosis is critical to hematopoietic homeostasis, and SFRs may represent previously unknown targets for tumor immunotherapy. 10.1126/sciimmunol.abj5501
    The Role of Cytokines including Interleukin-6 in COVID-19 induced Pneumonia and Macrophage Activation Syndrome-Like Disease. McGonagle Dennis,Sharif Kassem,O'Regan Anthony,Bridgewood Charlie Autoimmunity reviews Severe COVID-19 associated pneumonia patients may exhibit features of systemic hyper-inflammation designated under the umbrella term of macrophage activation syndrome (MAS) or cytokine storm, also known as secondary haemophagocytic lymphohistocytosis (sHLH). This is distinct from HLH associated with immunodeficiency states termed primary HLH -with radically different therapy strategies in both situations. COVID-19 infection with MAS typically occurs in subjects with adult respiratory distress syndrome (ARDS) and historically, non-survival in ARDS was linked to sustained IL-6 and IL-1 elevation. We provide a model for the classification of MAS to stratify the MAS-like presentation in COVID-19 pneumonia and explore the complexities of discerning ARDS from MAS. We discuss the potential impact of timing of anti-cytokine therapy on viral clearance and the impact of such therapy on intra-pulmonary macrophage activation and emergent pulmonary vascular disease. 10.1016/j.autrev.2020.102537
    Discrimination of COVID-19 From Inflammation-Induced Cytokine Storm Syndromes Using Disease-Related Blood Biomarkers. Arthritis & rheumatology (Hoboken, N.J.) OBJECTIVE:Infection with the novel coronavirus SARS-CoV-2 triggers severe illness with high mortality in a subgroup of patients. Such a critical course of COVID-19 is thought to be associated with the development of cytokine storm, a condition seen in macrophage activation syndrome (MAS) and secondary hemophagocytic lymphohistiocytosis (HLH). However, specific data demonstrating a clear association of cytokine storm with severe COVID-19 are still lacking. The aim of this study was to directly address whether immune activation in COVID-19 does indeed mimic the conditions found in these classic cytokine storm syndromes. METHODS:Levels of 22 biomarkers were quantified in serum samples from patients with COVID-19 (n = 30 patients, n = 83 longitudinal samples in total), patients with secondary HLH/MAS (n = 50), and healthy controls (n = 9). Measurements were performed using bead array assays and single-marker enzyme-linked immunosorbent assay. Serum biomarker levels were assessed for correlations with disease outcome. RESULTS:In patients with secondary HLH/MAS, we observed pronounced activation of the interleukin-18 (IL-18)-interferon-γ axis, increased serum levels of IL-1 receptor antagonist, intercellular adhesion molecule 1, and IL-8, and strongly reduced levels of soluble Fas ligand in the course of SARS-CoV-2 infection. These observations appeared to discriminate immune dysregulation in critical COVID-19 from the well-recognized characteristics of other cytokine storm syndromes. CONCLUSION:Serum biomarker profiles clearly separate COVID-19 from MAS or secondary HLH in terms of distinguishing the severe systemic hyperinflammation that occurs following SARS-CoV-2 infection. These findings could be useful in determining the efficacy of drugs targeting key molecules and pathways specifically associated with systemic cytokine storm conditions in the treatment of COVID-19. 10.1002/art.41763
    Etiologies and management of haemophagocytic lymphohistiocytosis: is it time for an updated protocol and targeted treatments? Posas-Mendoza Therese F,McLeod Cara,Davis William,Zakem Jerald,Quinet Robert Rheumatology (Oxford, England) OBJECTIVE:The objective of this study was to analyse the features, therapeutic approaches, and outcomes for adult patients with haemophagocytic lymphohistiocytosis (HLH) at a single centre. METHODS:This study was a retrospective chart review of all patients >18 years of age diagnosed with HLH according to HLH-2004 or H-score criteria at Ochsner Medical Center-New Orleans between 2013 and 2019. RESULTS:A total of 29 patients with HLH met inclusion criteria. A total of 7 patients had an underlying malignancy, 12 had an autoimmune disease, 2 were transplant patients, and 2 had a combination of malignancy, autoimmune disease, or immunodeficiency. A total of 6 patients developed HLH precipitated by infection alone. All 29 patients presented with fever. A total of 28 (97%) patients met H-score criteria, and only 20 (67%) met HLH-2004 criteria. Fifteen patients were treated with the HLH-2004 protocol. Of those treated with the HLH-2004 protocol, 73% (11/15) died, 8% (1/15) had recurrence of HLH, and 20% (3/15) had resolution of HLH. A total of 14 patients were treated with targeted therapy. Of those treated with targeted therapy, 93% (13/14) had resolution of HLH and 1 died. Targeted therapy included pulse steroids, tocilizumab, anakinra, IVIG, CSA, rituximab, and/or CYC in addition to antiviral or antibiotic therapy. CONCLUSION:Our findings suggested that the rheumatologic patient population responded well to a targeted therapeutic approach and poorly to the HLH-2004 protocol. Whether the poor outcomes found with the use of the HLH-2004 protocol are secondary to the protocol itself or the aggressive nature of malignancy-associated HLH is unclear. Further studies are needed to develop tailored therapeutic regimens. 10.1093/rheumatology/keaa741
    Expansion of CD4dimCD8+ T cells characterizes macrophage activation syndrome and other secondary HLH. Blood CD8+ T-cell activation has been demonstrated to distinguish patients with primary and infection-associated hemophagocytic lymphohistiocytosis (HLH) from patients with early sepsis. We evaluated the activation profile of CD8+ T cells in patients with various forms of secondary HLH (sHLH), including macrophage activation syndrome (MAS). Peripheral blood mononuclear cells from children with inactive systemic juvenile idiopathic arthritis (sJIA, n = 17), active sJIA (n = 27), MAS in sJIA (n = 14), infection-associated HLH (n = 7), and with other forms of sHLH (n = 9) were analyzed by flow cytometry. Compared with patients with active sJIA, in patients with MAS and sHLH of different origins, beside a significant increase in the frequency of CD38high/HLA-DR+CD8+ T cells, we found a significant increase in the frequency of CD8+ T cells expressing the CD4 antigen (CD4dimCD8+ T cells). These cells expressed high levels of the activation markers CD38 and HLA-DR, suggesting they were a subset of CD38high/HLA-DR+CD8+ T cells, as well as of the activation/exhaustion markers CD25, PD1, CD95, and interferon-γ. The frequency of CD4dimCD8+ T cells strongly correlated with most of the laboratory parameters of MAS severity and with circulating levels of CXCL9 and interleukin-18. These findings were confirmed in a prospective replication cohort in which no expansion of any particular T-cell receptor Vβ family in CD3+ T cells of patients with sHLH was found. Finally, frequency of CD4dimCD8+, but not of CD38high/HLA-DR+CD8+ T cells, significantly correlated with a clinical severity score, further supporting the involvement of these cells in MAS/sHLH pathogenesis. 10.1182/blood.2021013549
    Cytokines in systemic juvenile idiopathic arthritis and haemophagocytic lymphohistiocytosis: tipping the balance between interleukin-18 and interferon-γ. Put Karen,Avau Anneleen,Brisse Ellen,Mitera Tania,Put Stéphanie,Proost Paul,Bader-Meunier Brigitte,Westhovens René,Van den Eynde Benoit J,Orabona Ciriana,Fallarino Francesca,De Somer Lien,Tousseyn Thomas,Quartier Pierre,Wouters Carine,Matthys Patrick Rheumatology (Oxford, England) OBJECTIVES:To study the role of IFN-γ in the pathogenesis of systemic JIA (sJIA) and haemophagocytic lymphohistiocytosis (HLH) by searching for an IFN-γ profile, and to assess its relationship with other cytokines. METHODS:Patients with inactive (n = 10) and active sJIA (n = 10), HLH [n = 5; of which 3 had sJIA-associated macrophage activation syndrome (MAS)] and healthy controls (n = 16) were enrolled in the study. Cytokines and IFN-γ-induced genes and proteins were determined in plasma, in patient peripheral blood mononuclear cells (PBMCs) and in lymph node biopsies of one patient during both sJIA and MAS episodes. IFN-γ responses were investigated in healthy donor PBMCs, primary fibroblasts and endothelial cells. RESULTS:Plasma IFN-γ, IL-6 and IL-18 were elevated in active sJIA and HLH. Levels of IFN-γ and IFN-γ-induced proteins (IP-10/CXCL-10, IL-18BP and indoleamine 2,3-dioxygenase) in HLH were much higher than levels in active sJIA. Free IL-18 and ratios of IL-18/IFN-γ were higher in active sJIA compared with HLH. HLH PBMCs showed hyporesponsiveness to IFN-γ in vitro when compared with control and sJIA PBMCs. Endothelial cells and fibroblasts expressed IFN-γ-induced proteins in situ in lymph node staining of a MAS patient and in vitro upon stimulation with IFN-γ. CONCLUSION:Patients with active sJIA and HLH/MAS show distinct cytokine profiles, with highly elevated plasma levels of IFN-γ and IFN-γ-induced proteins typically found in HLH/MAS. In addition to PBMCs, histiocytes, endothelial cells and fibroblasts may contribute to an IFN-γ profile in plasma. Increasing levels of IFN-γ compared with IL-18 may raise suspicion about the development of MAS in sJIA. 10.1093/rheumatology/keu524
    Hemophagocytic syndromes. Janka Gritta E Blood reviews Hemophagocytic syndromes (hemophagocytic lymphohistiocytosis, HLH) represent a severe hyperinflammatory condition with the cardinal symptoms prolonged fever, cytopenias, hepatosplenomegaly, and hemophagocytosis by activated, morphologically benign macrophages. Biochemical markers include elevated ferritin and triglycerides, and low fibrinogen. Whereas in children several inherited immune deficiencies may lead to this syndrome, most adults with HLH have no known underlying immune defect. Nevertheless, impaired function of natural killer (NK) cells and cytotoxic T-cells (CTL) is characteristic for both genetic and acquired forms of HLH. Frequent triggers are infectious agents, mostly viruses of the herpes group. Malignant lymphomas, especially in adults, may be associated with HLH. A special form of HLH in rheumatic diseases is called macrophage-activation syndrome. Initially HLH may masquerade as a normal infection since all symptoms, even though less pronounced, may also be found in immune competent patients. Patients with HLH, however, cannot control the hyperinflammatory response which, if untreated, is fatal in genetic cases and in a high percentage of acquired cases. Awareness of the clinical symptoms and of the diagnostic criteria of HLH is important to start life-saving therapy with immunosuppressive/immunomodulatory agents in time. 10.1016/j.blre.2007.05.001
    Reactive hemophagocytic syndrome complicating the treatment of inflammatory bowel disease. James Dustin G,Stone Christian D,Wang Hanlin L,Stenson William F Inflammatory bowel diseases BACKGROUND AND AIMS:Reactive hemophagocytic syndrome (RHS) is a rare disease in which inappropriately activated macrophages consume bone marrow-derived cells. Most cases are associated with infection in the setting of immunodeficiency. The widespread use of immunosuppressive therapy in the treatment of inflammatory bowel disease (IBD) places patients with Crohn's disease and ulcerative colitis at risk of this complication. No concerted effort has been made to alert gastroenterologists of this condition, and treatment recommendations are lacking. The aims of this study were to describe the clinical and laboratory features of RHS associated with IBD and to review diagnostic criteria, treatment options, and pathogenesis. MATERIALS AND METHODS:Clinical and laboratory data were pooled from the clinical practice of the investigators and from published cases. Descriptive statistics were performed. RESULTS AND CONCLUSIONS:Seven cases of RHS complicating the treatment of IBD were identified. All patients were on immunosuppressive therapy, with nearly half taking >1 agent. All patients presented with fever, leukopenia, anemia, and hyperferritinemia. Infection by a member of the herpesvirus family or an intracellular pathogen precipitated RHS in 6 of 7 patients. The mortality rate was 29%. The diagnosis of RHS should be considered in patients with IBD taking immunosuppressive therapy who present with fever and cytopenia. Evaluation should begin with a serum ferritin. In patients with a serum ferritin > or =10,000 ng/mL, a bone marrow biopsy should be performed to confirm hemophagocytosis. If the initial evaluation is negative, then clinical suspicion should be maintained until the episode resolves. 10.1097/01.MIB.0000225333.83861.16
    Munc18-2 deficiency causes familial hemophagocytic lymphohistiocytosis type 5 and impairs cytotoxic granule exocytosis in patient NK cells. Côte Marjorie,Ménager Mickaël M,Burgess Agathe,Mahlaoui Nizar,Picard Capucine,Schaffner Catherine,Al-Manjomi Fahad,Al-Harbi Musa,Alangari Abdullah,Le Deist Françoise,Gennery Andrew R,Prince Nathalie,Cariou Astrid,Nitschke Patrick,Blank Ulrich,El-Ghazali Gehad,Ménasché Gaël,Latour Sylvain,Fischer Alain,de Saint Basile Geneviève The Journal of clinical investigation Familial hemophagocytic lymphohistiocytosis (FHL) is a genetically heterogeneous autosomal recessive immune disorder characterized by the occurrence of uncontrolled activation of lymphocytes and macrophages infiltrating multiple organs. Disease-causing mutations in the perforin (PRF1; also known as FHL2), Munc13-4 (UNC13D; also known as FHL3), and syntaxin-11 (STX11; also known as FHL4) genes have been identified in individuals with FHL. These genes all encode proteins involved in the cytotoxic activity of lymphocytes. Here, we show that the gene encoding syntaxin-binding protein 2 (Munc18-2; official gene symbol STXBP2) is mutated in another subset of patients with FHL (designated by us as "FHL5"). Lymphoblasts isolated from these patients had strongly decreased STXBP2 protein expression, and NK cells exhibited impaired cytotoxic granule exocytosis, a defect that could be overcome by ectopic expression of wild-type STXBP2. Furthermore, we provide evidence that syntaxin-11 is the main partner of STXBP2 in lymphocytes, as its expression required the presence of STXBP2. Our work shows that STXBP2 deficiency causes FHL5. These data indicate that STXBP2 is required at a late step of the secretory pathway for the release of cytotoxic granules by binding syntaxin 11, another component of the intracellular membrane fusion machinery. 10.1172/JCI40732
    Macrophage Activation Marker Soluble CD163 Associated with Fatal and Severe Ebola Virus Disease in Humans. McElroy Anita K,Shrivastava-Ranjan Punya,Harmon Jessica R,Martines Roosecelis B,Silva-Flannery Luciana,Flietstra Timothy D,Kraft Colleen S,Mehta Aneesh K,Lyon G Marshall,Varkey Jay B,Ribner Bruce S,Nichol Stuart T,Zaki Sherif R,Spiropoulou Christina F Emerging infectious diseases Ebola virus disease (EVD) is associated with elevated cytokine levels, and hypercytokinemia is more pronounced in fatal cases. This type of hyperinflammatory state is reminiscent of 2 rheumatologic disorders known as macrophage activation syndrome and hemophagocytic lymphohistiocytosis, which are characterized by macrophage and T-cell activation. An evaluation of 2 cohorts of patients with EVD revealed that a marker of macrophage activation (sCD163) but not T-cell activation (sCD25) was associated with severe and fatal EVD. Furthermore, substantial immunoreactivity of host tissues to a CD163-specific antibody, predominantly in areas of extensive immunostaining for Ebola virus antigens, was observed in fatal cases. These data suggest that host macrophage activation contributes to EVD pathogenesis and that directed antiinflammatory therapies could be beneficial in the treatment of EVD. 10.3201/eid2502.181326
    Interferon-γ primes macrophages for pathogen ligand-induced killing via a caspase-8 and mitochondrial cell death pathway. Immunity Cell death plays an important role during pathogen infections. Here, we report that interferon-γ (IFNγ) sensitizes macrophages to Toll-like receptor (TLR)-induced death that requires macrophage-intrinsic death ligands and caspase-8 enzymatic activity, which trigger the mitochondrial apoptotic effectors, BAX and BAK. The pro-apoptotic caspase-8 substrate BID was dispensable for BAX and BAK activation. Instead, caspase-8 reduced pro-survival BCL-2 transcription and increased inducible nitric oxide synthase (iNOS), thus facilitating BAX and BAK signaling. IFNγ-primed, TLR-induced macrophage killing required iNOS, which licensed apoptotic caspase-8 activity and reduced the BAX and BAK inhibitors, A1 and MCL-1. The deletion of iNOS or caspase-8 limited SARS-CoV-2-induced disease in mice, while caspase-8 caused lethality independent of iNOS in a model of hemophagocytic lymphohistiocytosis. These findings reveal that iNOS selectively licenses programmed cell death, which may explain how nitric oxide impacts disease severity in SARS-CoV-2 infection and other iNOS-associated inflammatory conditions. 10.1016/j.immuni.2022.01.003
    Macrophage activation syndrome and cytokine-directed therapies. Schulert Grant S,Grom Alexei A Best practice & research. Clinical rheumatology Macrophage activation syndrome (MAS) is an episode of overwhelming inflammation that occurs most commonly in children with systemic juvenile idiopathic arthritis (SJIA). It is characterized by expansion and activation of T lymphocytes and hemophagocytic macrophages and bears great similarity to hemophagocytic lymphohistiocytosis (HLH). This disorder has substantial morbidity and mortality, and there is frequently a delay in recognition and initiation of treatment. Here, we will review what is known about the pathogenesis of MAS and, in particular, its similarities to HLH. The development of MAS is characterized by a cytokine storm, with the elaboration of numerous pro-inflammatory cytokines. We will examine the evidence for various cytokines in the initiation and pathogenesis of MAS and discuss how new biologic therapies may alter the risk of MAS. Finally, we will review current treatment options for MAS and examine how cytokine-directed therapy could serve as novel treatment modalities. 10.1016/j.berh.2014.03.002
    Understanding the spectrum of haemophagocytic lymphohistiocytosis: update on diagnostic challenges and therapeutic options. Brisse Ellen,Matthys Patrick,Wouters Carine H British journal of haematology The cytokine storm syndrome 'haemophagocytic lymphohistiocytosis' (HLH) is an under-recognized hyperinflammatory disorder, causing high morbidity and mortality risk in children and adults. It can be subdivided into a primary, genetic form and a secondary, acquired form that complicates diverse infections, malignancies and autoimmune or autoinflammatory disorders. Both subtypes present with the same spectrum of non-specific symptoms, making accurate diagnosis and rapid treatment initiation challenging. In the last decade, increased awareness and international collaborative efforts fuelled a marked progress in diagnostic protocols and novel treatment strategies for HLH and new diagnostic guidelines are being tailored to specific secondary HLH subtypes. Therapy is gradually shifting its focus from overall immunosuppression towards targeting specific cytokines, cell types or signalling pathways underlying pathophysiology. Nevertheless, continued research efforts remain indispensable to customize therapy to individual patient needs. 10.1111/bjh.14144
    Diagnosis and Management of Secondary HLH/MAS Following HSCT and CAR-T Cell Therapy in Adults; A Review of the Literature and a Survey of Practice Within EBMT Centres on Behalf of the Autoimmune Diseases Working Party (ADWP) and Transplant Complications Working Party (TCWP). Sandler Robert David,Tattersall Rachel Scarlett,Schoemans Helene,Greco Raffaella,Badoglio Manuela,Labopin Myriam,Alexander Tobias,Kirgizov Kirill,Rovira Montserrat,Saif Muhammad,Saccardi Riccardo,Delgado Julio,Peric Zinaida,Koenecke Christian,Penack Olaf,Basak Grzegorz,Snowden John Andrew Frontiers in immunology Secondary haemophagocytic lymphohistiocytosis (sHLH) or Macrophage Activation Syndrome (MAS) is a life-threatening hyperinflammatory syndrome that can occur in patients with severe infections, malignancy or autoimmune diseases. It is also a rare complication of haematopoetic stem cell transplantation (HSCT), with a high mortality. It may be associated with graft vs. host disease in the allogeneic HSCT setting. It is also reported following CAR-T cell therapy, but differentiation from cytokine release syndrome (CRS) is challenging. Here, we summarise the literature and present results of a survey of current awareness and practice in EBMT-affiliated centres of sHLH/MAS following HSCT and CAR-T cell therapy. An online questionnaire was sent to the principal investigators of all EBMT member transplant centres treating adult patients (18 years and over) inviting them to provide information regarding: number of cases of sHLH/MAS seen in their centre over 3 years (2016-2018 inclusive); screening strategies and use of existing diagnostic/classification criteria and treatment protocols. 114/472 centres from 24 different countries responded (24%). We report estimated rates of sHLH/MAS of 1.09% (95% CI = 0.89-1.30) following allogeneic HSCT, 0.15% (95% CI = 0.09-5.89) following autologous HSCT and 3.48% (95% CI = 0.95-6.01) following CAR-T cell therapy. A majority of centres (70%) did not use a standard screening protocol. Serum ferritin was the most commonly used screening marker at 78% of centres, followed by soluble IL-2 receptor (24%), triglycerides (15%), and fibrinogen (11%). There was significant variation in definition of "clinically significant" serum ferritin levels ranging from 500 to 10,000 μg/mL. The most commonly used criteria to support diagnosis were HLH-2004 (43%) and the H score (15%). Eighty percent of responders reported using no standard management protocol, but reported using combinations of corticosteroids, chemotherapeutic agents, cytokine blockade, and monoclonal antibodies. There is a remarkable lack of consistency between EBMT centres in the approach to screening, diagnosis and management. Further research in this field is needed to raise awareness of and inform harmonised, evidence-based approaches to the recognition and treatment of sHLH/MAS following HSCT/CAR-T cell therapy. 10.3389/fimmu.2020.00524
    Ruxolitinib-combined doxorubicin-etoposide-methylprednisolone regimen as a salvage therapy for refractory/relapsed haemophagocytic lymphohistiocytosis: a single-arm, multicentre, phase 2 trial. Wang Jingshi,Zhang Rui,Wu Xiaoyan,Li Fei,Yang Haixia,Liu Ligen,Guo Haixia,Zhang Xuejun,Mai Huirong,Li Hui,Wang Zhao British journal of haematology We performed a multicentre, non-randomised trial (NCT03533790) to investigate the efficacy of ruxolitinib combined with the doxorubicin-etoposide-methylprednisolone (Ru-DEP) regimen as a salvage therapy for refractory/relapsed haemophagocytic lymphohistiocytosis (HLH). All patients failing to achieve a complete or partial response 2 weeks after initial HLH-94/HLH-04 regimen or relapsed after remission were enrolled in the study between June 2018 and June 2019. The efficacy was evaluated 2 weeks after initiating Ru-DEP salvage therapy. Fifty-four eligible patients with refractory/relapsed (R/R) HLH were enrolled. One case could not be evaluated for efficacy. Excluding 12 patients who had previously received the DEP regimen, the overall response rate was 32 of 41 (78·0%) patients, with eight of 41 (19·5%) achieving complete response and 24 of 41 (58·5%) attaining a partial response. Of the R/R HLH patients who had previously received the DEP regimen, 7 of 12 (58·3%) achieved a partial response. Ferritin and soluble CD25 concentrations were significantly lower (P < 0·05), while the platelet count increased significantly (P = 0·034), and triglycerides decreased significantly (P = 0·002) compared with those before treatment. The Ru-DEP regimen may be a safe and effective salvage therapy, remaining effective in refractory/relapsed HLH following DEP treatment, especially in macrophage activation syndrome. In addition, the regimen can be considered for patients with contraindications to glucocorticoid, especially those with gastrointestinal bleeding. 10.1111/bjh.17331
    The genetics of macrophage activation syndrome. Schulert Grant S,Cron Randy Q Genes and immunity Macrophage activation syndrome (MAS), or secondary hemophagocytic lymphohistiocytosis (HLH), is a cytokine storm syndrome associated with multi-organ system dysfunction and high mortality rates. Laboratory and clinical features resemble primary HLH, which arises in infancy (1 in 50,000 live births) from homozygous mutations in various genes critical to the perforin-mediated cytolytic pathway employed by NK cells and cytotoxic CD8 T lymphocytes. MAS/secondary HLH is about ten times more common and typically presents beyond infancy extending into adulthood. The genetics of MAS are far less defined than for familial HLH. However, the distinction between familial HLH and MAS/secondary HLH is blurred by the finding of heterozygous perforin-pathway mutations in MAS patients, which may function as hypomorphic or partial dominant-negative alleles and contribute to disease pathogenesis. In addition, mutations in a variety of other pathogenic pathways have been noted in patients with MAS/secondary HLH. Many of these genetically disrupted pathways result in a similar cytokine storm syndrome, and can be broadly categorized as impaired viral control (e.g., SH2P1A), dysregulated inflammasome activity (e.g., NLRC4), other immune defects (e.g., IKBKG), and dysregulated metabolism (e.g., LIPA). Collectively these genetic lesions likely combine with states of chronic inflammation, as seen in various rheumatic diseases (e.g., still disease), with or without identified infections, to result in MAS pathology as explained by the threshold model of disease. This emerging paradigm may ultimately support genetic risk stratification for high-risk chronic and even acute inflammatory disorders. Moving forward, continued whole-exome and -genome sequencing will likely identify novel MAS gene associations, as well as noncoding mutations altering levels of gene expression. 10.1038/s41435-020-0098-4
    Interleukin-18 diagnostically distinguishes and pathogenically promotes human and murine macrophage activation syndrome. Weiss Eric S,Girard-Guyonvarc'h Charlotte,Holzinger Dirk,de Jesus Adriana A,Tariq Zeshan,Picarsic Jennifer,Schiffrin Eduardo J,Foell Dirk,Grom Alexei A,Ammann Sandra,Ehl Stephan,Hoshino Tomoaki,Goldbach-Mansky Raphaela,Gabay Cem,Canna Scott W Blood Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening hyperferritinemic systemic inflammatory disorders. Although profound cytotoxic impairment causes familial HLH (fHLH), the mechanisms driving non-fHLH and MAS are largely unknown. MAS occurs in patients with suspected rheumatic disease, but the mechanistic basis for its distinction is unclear. Recently, a syndrome of recurrent MAS with infantile enterocolitis caused by NLRC4 inflammasome hyperactivity highlighted the potential importance of interleukin-18 (IL-18). We tested this association in hyperferritinemic and autoinflammatory patients and found a dramatic correlation of MAS risk with chronic (sometimes lifelong) elevation of mature IL-18, particularly with IL-18 unbound by IL-18 binding protein, or free IL-18. In a mouse engineered to carry a disease-causing germ line NLRC4 mutation, we observed inflammasome-dependent, chronic IL-18 elevation. Surprisingly, this NLRC4-induced systemic IL-18 elevation derived entirely from intestinal epithelia. NLRC4 intestines were histologically normal but showed increased epithelial turnover and upregulation of interferon-γ-induced genes. Assessing cellular and tissue expression, classical inflammasome components such as , and predominated in neutrophils, whereas and were distinctly epithelial. Demonstrating the importance of free IL-18, transgenic mice exhibited free IL-18 elevation and more severe experimental MAS. NLRC4 mice, whose free IL-18 levels were normal, did not. Thus, we describe a unique connection between MAS risk and chronic IL-18, identify epithelial inflammasome hyperactivity as a potential source, and demonstrate the pathogenicity of free IL-18. These data suggest an IL-18-driven pathway, complementary to the cytotoxic impairment of fHLH, with potential as a distinguishing biomarker and therapeutic target in MAS. 10.1182/blood-2017-12-820852
    The Immunology of Macrophage Activation Syndrome. Crayne Courtney B,Albeituni Sabrin,Nichols Kim E,Cron Randy Q Frontiers in immunology Synonymous with secondary hemophagocytic lymphohistiocytosis, macrophage activation syndrome (MAS) is a term used by rheumatologists to describe a potentially life-threatening complication of systemic inflammatory disorders, most commonly systemic juvenile idiopathic arthritis (sJIA) and systemic lupus erythematosus (SLE). Clinical and laboratory features of MAS include sustained fever, hyperferritinemia, pancytopenia, fibrinolytic coagulopathy, and liver dysfunction. Soluble interleukin-2 receptor alpha chain (sCD25) and sCD163 may be elevated, and histopathology often reveals characteristic increased hemophagocytic activity in the bone marrow (and other tissues), with positive CD163 (histiocyte) staining. A common hypothesis as to the pathophysiology of many cases of MAS proposes a defect in lymphocyte cytolytic activity. Specific heterozygous gene mutations in familial HLH-associated cytolytic pathway genes (e.g., ) have been linked to a substantial subset of MAS patients. In addition, the pro-inflammatory cytokine environment, particularly IL-6, has been shown to decrease NK cell cytolytic function. The inability of NK cells and cytolytic CD8 T cells to lyse infected and otherwise activated antigen presenting cells results in prolonged cell-to-cell (innate and adaptive immune cells) interactions and amplification of a pro-inflammatory cytokine cascade. The cytokine storm results in activation of macrophages, causing hemophagocytosis, as well as contributing to multi-organ dysfunction. In addition to macrophages, dendritic cells likely play a critical role in antigen presentation to cytolytic lymphocytes, as well as contributing to cytokine expression. Several cytokines, including tumor necrosis factor, interferon-gamma, and numerous interleukins (i.e., IL-1, IL-6, IL-18, IL-33), have been implicated in the cytokine cascade. In addition to broadly immunosuppressive therapies, novel cytokine targeted treatments are being explored to dampen the overly active immune response that is responsible for much of the pathology seen in MAS. 10.3389/fimmu.2019.00119
    Cytokine storm in severe COVID-19 pneumonia. Gürsoy Bengül,Sürmeli Cemile D,Alkan Mustafa,Satıcı Celal,Altunok Elif Sargın,Kamat Sadettin,Demirok Berna,Demirkol Mustafa A,Börü Akaberk Journal of medical virology In this study, laboratorial parameters of hospitalized novel coronavirus (COVID-19) patients, who were complicated with severe pneumonia, were compared with the findings of cytokine storm developing in macrophage activation syndrome (MAS)/secondary hemophagocytic lymphohistiocytosis (sHLH). Severe pneumonia occurred as a result of cytokine storm in some patients who needed intensive care unit (ICU), and it is aimed to determine the precursive parameters in this situation. Also in this study, the aim is to identify laboratory criteria that predict worsening disease and ICU intensification, as well as the development of cytokine storm. This article comprises a retrospective cohort study of patients admitted to a single institution with COVID-19 pneumonia. This study includes 150 confirmed COVID-19 patients with severe pneumonia. When they were considered as severe pneumonia patients, the clinic and laboratory parameters of this group are compared with H-score criteria. Patients are divided into two subgroups; patients with worsened symptoms who were transferred into tertiary ICU, and patients with stable symptoms followed in the clinic. For the patients with confirmed COVID-19 infection, after they become complicated with severe pneumonia, lymphocytopenia (55.3%), anemia (12.0%), thrombocytopenia (19.3%), hyperferritinemia (72.5%), hyperfibrinogenemia (63.7%) and elevated lactate dehydrogenase (LDH) (90.8%), aspartate aminotransaminase (AST) (31.3%), alanine aminotransaminase (ALT) (20.7%) are detected. There were no significant changes in other parameters. Blood parameters between the pre-ICU period and the ICU period (in which their situation had been worsened and acute respiratory distress syndrome [ARDS] was developed) were also compared. In the latter group lymphocyte levels were found significantly reduced (p = 0.01), and LDH, highly sensitive troponin (hs-troponin), procalcitonin, and triglyceride levels were significantly increased (p < 0.05). In addition, there was no change in hemoglobin, leukocyte, platelet, ferritin, and liver function test levels, including patients who developed ARDS, similar to the cytokine storm developed in MAS/sHLH. COVID-19 pneumonia has similar findings as hyperinflammatory syndromes but does not seem to have typical features as in cytokine storm developed in MAS/sHLH. In the severe patient group who has started to develop ARDS signs, a decrease in lymphocyte level in addition to the elevated LDH, hs-troponin, procalcitonin, and triglyceride levels can be a predictor in progression to ICU admission and could help in the planning of anti-cytokine therapy. 10.1002/jmv.27068
    Engulfment of hematopoietic stem cells caused by down-regulation of CD47 is critical in the pathogenesis of hemophagocytic lymphohistiocytosis. Kuriyama Takuro,Takenaka Katsuto,Kohno Kentaro,Yamauchi Takuji,Daitoku Shinya,Yoshimoto Goichi,Kikushige Yoshikane,Kishimoto Junji,Abe Yasunobu,Harada Naoki,Miyamoto Toshihiro,Iwasaki Hiromi,Teshima Takanori,Akashi Koichi Blood Hemophagocytic lymphohistiocytosis (HLH) is characterized by deregulated engulfment of hematopoietic stem cells (HSCs) by BM macrophages, which are activated presumably by systemic inflammatory hypercytokinemia. In the present study, we show that the pathogenesis of HLH involves impairment of the antiphagocytic system operated by an interaction between surface CD47 and signal regulatory protein α (SIRPA). In HLH patients, changes in expression levels and HLH-specific polymorphism of SIRPA were not found. In contrast, the expression of surface CD47 was down-regulated specifically in HSCs in association with exacerbation of HLH, but not in healthy subjects. The number of BM HSCs in HLH patients was reduced to approximately 20% of that of healthy controls and macrophages from normal donors aggressively engulfed HSCs purified from HLH patients, but not those from healthy controls in vitro. Furthermore, in response to inflammatory cytokines, normal HSCs, but not progenitors or mature blood cells, down-regulated CD47 sufficiently to be engulfed by macrophages. The expression of prophagocytic calreticulin was kept suppressed at the HSC stage in both HLH patients and healthy controls, even in the presence of inflammatory cytokines. These data suggest that the CD47-SIRPA antiphagocytic system plays a key role in the maintenance of HSCs and that its disruption by HSC-specific CD47 down-regulation might be critical for HLH development. 10.1182/blood-2012-02-408864
    Macrophage Activation-Like Syndrome: A Distinct Entity Leading to Early Death in Sepsis. Karakike Eleni,Giamarellos-Bourboulis Evangelos J Frontiers in immunology Hemophagocytic lymphohistocytosis (HLH) is characterized by fulminant cytokine storm leading to multiple organ dysfunction and high mortality. HLH is classified into familial (fHLH) and into secondary (sHLH). fHLH is rare and it is due to mutations of genes encoding for perforin or excretory granules of natural killer (NK) cells of CD8-lymphocytes. sHLH is also known as macrophage activation syndrome (MAS). Macrophage activation syndrome (MAS) in adults is poorly studied. Main features are fever, hepatosplenomegaly, hepatobiliary dysfunction (HBD), coagulopathy, cytopenia of two to three cell lineages, increased triglycerides and hemophagocytosis in the bone marrow. sHLH/MAS complicates hematologic malignancies, autoimmune disorders and infections mainly of viral origin. Pathogenesis is poorly understood and it is associated with increased activation of macrophages and NK cells. An autocrine loop of interleukin (IL)-1β over-secretion leads to cytokine storm of IL-6, IL-18, ferritin, and interferon-gamma; soluble CD163 is highly increased from macrophages. The true incidence of sHLH/MAS among patients with sepsis has only been studied in the cohort of the Hellenic Sepsis Study Group. Patients meeting the Sepsis-3 criteria and who had positive HSscore or co-presence of HBD and disseminated intravascular coagulation (DIC) were classified as patients with macrophage activation-like syndrome (MALS). The frequency of MALS ranged between 3 and 4% and it was an independent entity associated with early mortality after 10 days. Ferritin was proposed as a diagnostic and surrogate biomarker. Concentrations >4,420 ng/ml were associated with diagnosis of MALS with 97.1% specificity and 98% negative predictive value. Increased ferritin was also associated with increased IL-6, IL-18, IFNγ, and sCD163 and by decreased IL-10/TNFα ratio. A drop of ferritin by 15% the first 48 h was a surrogate finding of favorable outcome. There are 10 on-going trials in adults with sHLH; two for the development of biomarkers and eight for management. Only one of them is focusing in sepsis. The acronym of the trial is PROVIDE (ClinicalTrials.gov NCT03332225) and it is a double-blind randomized clinical trial aiming to deliver to patients with septic shock treatment targeting their precise immune state. Patients diagnosed with MALS are receiving randomized treatment with placebo or the IL-1β blocker anakinra. 10.3389/fimmu.2019.00055
    Nephrotic syndrome associated with hemophagocytic syndrome. Thaunat O,Delahousse M,Fakhouri F,Martinez F,Stephan J-L,Noël L-H,Karras A Kidney international Hemophagocytic syndrome (HPS) is defined by bone marrow and organ infiltration by activated, nonmalignant macrophages, which phagocytose blood cells. The clinical spectrum of HPS is broad, but renal involvement has rarely been investigated. We report a previously unknown renal manifestation of HPS: nephrotic syndrome. This multicentric retrospective study included patients fulfilling the following criteria: (i) no history of nephropathy; (ii) HPS diagnosis with histologic evidence of hemophagocytosis; (iii) occurrence of nephrotic syndrome during HPS; and (iv) available renal histology. Using the same criteria, we also searched the literature for additional cases. We identified nine patients retrospectively and found two additional cases in the literature (five males and six females, whose mean age was 34 +/- 27 years). Black African patients predominated (63.6%). HPS was due to lymphoma (six cases), infectious disease (three cases), and autoimmune disease (one case), and was primary in one patient. Acute renal failure was associated with nephrotic syndrome in 10/11 cases. Renal histology showed acute tubular necrosis associated with collapsing glomerulopathy in five patients (all Africans with negative human immunodeficiency virus serology), minimal change glomerulopathy in four, and thrombotic-microangiopathy with abnormal podocytes in two. Death occurred in seven cases. Nephrotic syndrome should be included among the renal complications of HPS with acute renal failure. We postulate that abnormal T-cell activation and/or high pro-inflammatory cytokine levels during HPS might cause podocyte injuries, especially among African patients with a susceptible genetic background. 10.1038/sj.ki.5000352
    Neutralization of IFN-γ reverts clinical and laboratory features in a mouse model of macrophage activation syndrome. Prencipe Giusi,Caiello Ivan,Pascarella Antonia,Grom Alexei A,Bracaglia Claudia,Chatel Laurence,Ferlin Walter G,Marasco Emiliano,Strippoli Raffaele,de Min Cristina,De Benedetti Fabrizio The Journal of allergy and clinical immunology BACKGROUND:The pathogenesis of macrophage activation syndrome (MAS) is not clearly understood: a large body of evidence supports the involvement of mechanisms similar to those implicated in the setting of primary hemophagocytic lymphohistiocytosis. OBJECTIVE:We sought to investigate the pathogenic role of IFN-γ and the therapeutic efficacy of IFN-γ neutralization in an animal model of MAS. METHODS:We used an MAS model established in mice transgenic for human IL-6 (IL-6TG mice) challenged with LPS (MAS mice). Levels of IFN-γ and IFN-γ-inducible chemokines were evaluated by using real-time PCR in the liver and spleen and by means of ELISA in plasma. IFN-γ neutralization was achieved by using the anti-IFN-γ antibody XMG1.2 in vivo. RESULTS:Mice with MAS showed a significant upregulation of the IFN-γ pathway, as demonstrated by increased mRNA levels of Ifng and higher levels of phospho-signal transducer and activator of transcription 1 in the liver and spleen and increased expression of the IFN-γ-inducible chemokines Cxcl9 and Cxcl10 in the liver and spleen, as well as in plasma. A marked increase in Il12a and Il12b expression was also found in livers and spleens of mice with MAS. In addition, mice with MAS had a significant increase in numbers of liver CD68 macrophages. Mice with MAS treated with an anti-IFN-γ antibody showed a significant improvement in survival and body weight recovery associated with a significant amelioration of ferritin, fibrinogen, and alanine aminotransferase levels. In mice with MAS, treatment with the anti-IFN-γ antibody significantly decreased circulating levels of CXCL9, CXCL10, and downstream proinflammatory cytokines. The decrease in CXCL9 and CXCL10 levels paralleled the decrease in serum levels of proinflammatory cytokines and ferritin. CONCLUSION:These results provide evidence for a pathogenic role of IFN-γ in the setting of MAS. 10.1016/j.jaci.2017.07.021
    What nephrologists need to know about hemophagocytic syndrome. Karras Alexandre Nature reviews. Nephrology Hemophagocytic syndrome (HPs) is a rare but distinct condition caused by inappropriate and dysregulated activation of the immune system. HPs is characterized by febrile hepatosplenomegaly, pancytopenia, hypofibrinemia and liver dysfunction; these changes are associated with the infiltration of bone marrow and organs by nonmalignant macrophages that phagocytose blood cells. Primary HPs is linked to inherited immune dysregulation, whereas secondary HPs tends to be triggered by an infectious or neoplastic disease. Multiorgan failure can complicate this life-threatening condition and renal involvement has frequently been reported; however, precise descriptions of the renal manifestations of HPs are lacking. Acute kidney injury due to tubular necrosis is the most common renal presentation, but nephrotic syndrome can also occur. HPs can be observed in immunocompromised patients and nephrologists must be aware that this condition can occur in renal transplant recipients. Mortality in patients with HPs can be as high as 50%. Despite considerable advances in the treatment of familial HPs, no specific therapy has demonstrated a consistent capacity to control reactive HPs when combined with suppression of the triggering factor. This review summarizes the presentation, causes, pathophysiology and renal features of HPs for the benefit of the practicing nephrologist. 10.1038/nrneph.2009.73
    Mechanisms of action of ruxolitinib in murine models of hemophagocytic lymphohistiocytosis. Albeituni Sabrin,Verbist Katherine C,Tedrick Paige E,Tillman Heather,Picarsic Jennifer,Bassett Rachel,Nichols Kim E Blood Hemophagocytic lymphohistiocytosis (HLH) is an often-fatal disorder characterized by the overactivation of T cells and macrophages that excessively produce proinflammatory cytokines, including interferon-γ (IFN-γ). Previously, we reported that the JAK inhibitor ruxolitinib dampens T-cell activation and lessens inflammation in a model of HLH in which perforin-deficient ( ) mice are infected with lymphocytic choriomeningitis virus (LCMV). Ruxolitinib inhibits signaling downstream of IFN-γ, as well as several other JAK-dependent cytokines. As a consequence, it remained unclear whether ruxolitinib was exerting its beneficial effects in HLH by inhibiting IFN-γ signaling or by targeting signaling initiated by other proinflammatory cytokines. To address this question, we compared the effects of ruxolitinib with those obtained using an IFN-γ-neutralizing antibody (αIFN-γ) in 2 murine HLH models. In both models, ruxolitinib and αIFN-γ reduced inflammation-associated anemia, indicating that ruxolitinib operates in an IFN-γ-dependent manner to reverse this HLH manifestation. In contrast, the number and activation status of T cells and neutrophils, as well as their infiltration into tissues, were significantly reduced following treatment with ruxolitinib, but they remained unchanged or were increased following treatment with αIFN-γ. Notably, despite discontinuation of ruxolitinib, LCMV-infected mice exhibited enhanced survival compared with mice in which αIFN-γ was discontinued. This protective effect could be mimicked by transient treatment with αIFN-γ and a neutrophil-depleting antibody. Thus, ruxolitinib operates through IFN-γ-dependent and -independent mechanisms to dampen HLH by targeting the deleterious effects of T cells and neutrophils, with the latter representing an unappreciated and understudied cell type that contributes to HLH pathogenesis. 10.1182/blood.2019000761
    Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis Mimicking Lymphoma on FDG PET/CT. Pan Qingqing,Luo Yaping,Wu Huanwen,Ma Yanru,Li Fang Clinical nuclear medicine A 15-year-old boy with fever, pancytopenia, and hepatosplenomegaly was diagnosed as hemophagocytic lymphohistiocytosis (HLH). F-FDG PET/CT showed hypermetabolic foci in the liver, spleen, and bone marrow, as well as multiple FDG-avid lymph nodes, which were highly suggestive of lymphoma. Specimens from splenectomy depicted a large number of macrophages/histiocytes with hemophagocytosis of erythrocytes, without evidence of malignancy. Considering increased Epstein-Barr virus (EBV) DNA in peripheral blood and positive staining for EBV-encoded RNA in the spleen, EBV-associated HLH was confirmed. This case indicates that FDG-avid foci in the liver, spleen, and bone marrow may also be seen in EBV-associated HLH. 10.1097/RLU.0000000000001923
    Hemophagocytic syndromes--an update. Janka Gritta E,Lehmberg Kai Blood reviews Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome and not an independent disease. HLH represents the extreme end of a severe uncontrolled hyperinflammatory reaction that can occur in many underlying conditions. Genetic forms of HLHs are due to defects in transport, processing and function of cytotoxic granules in natural killer cells and cytotoxic T lymphocytes, and are not restricted to manifestation in childhood. Acquired forms of HLH are encountered in infections, autoinflammatory and autoimmune diseases, malignancies, acquired immune deficiency. Functional tests allow for differentiation between genetic and acquired HLH. Treatment aims at suppressing hypercytokinemia and eliminating activated and infected cells. It includes immunomodulatory and immunosuppressive agents, cytostatics, T-cell and cytokine antibodies. In genetic HLH cure can only be achieved with hematopoietic stem cell transplantation. Reduced-intensity conditioning regimens have considerably improved survival. 10.1016/j.blre.2014.03.002
    Association of IRF5 polymorphisms with susceptibility to hemophagocytic lymphohistiocytosis in children. Yanagimachi Masakatsu,Goto Hiroaki,Miyamae Takako,Kadota Keisuke,Imagawa Tomoyuki,Mori Masaaki,Sato Hidenori,Yanagisawa Ryu,Kaneko Tetsuji,Morita Satoshi,Ishii Eiichi,Yokota Shumpei Journal of clinical immunology INTRODUCTION:Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome and has a varied genetic background. The polymorphism of interferon regulatory factor 5 gene (IRF5) was reported to be associated with susceptibility to macrophage activation syndrome. IRF5 acts as a master transcription factor in the activation of pro-inflammatory cytokines. We assessed associations of IRF5 gene polymorphisms with susceptibility to secondary HLH. METHODS:Three IRF5 single nucleotide polymorphisms (rs729302, rs2004640, and rs2280714) were genotyped using TaqMan assays in 82 secondary HLH patients and 188 control subjects. RESULTS:There was a significant association of the GT/TT genotype at rs2004640 with secondary HLH susceptibility (p < 0.01). The IRF5 haplotype (rs729302 A, rs2004640 T, and rs2280714 T) was associated with secondary HLH susceptibility (p < 0.01). CONCLUSIONS:These findings indicate that IRF5 is a genetic factor influencing the susceptibility to secondary HLH and that the IRF5-associated immune response contributes to the pathogenesis of HLH. 10.1007/s10875-011-9583-x
    Protection from inflammatory organ damage in a murine model of hemophagocytic lymphohistiocytosis using treatment with IL-18 binding protein. Chiossone Laura,Audonnet Sandra,Chetaille Bruno,Chasson Lionel,Farnarier Catherine,Berda-Haddad Yael,Jordan Stefan,Koszinowski Ulrich H,Dalod Marc,Mazodier Karin,Novick Daniela,Dinarello Charles A,Vivier Eric,Kaplanski Gilles Frontiers in immunology Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition due to the association of an infectious agent with lymphocyte cytotoxicity defects, either of congenital genetic origin in children or presumably acquired in adults. In HLH patients, an excess of lymphocyte or macrophage cytokines, such as IFN-γ and TNFα is present in serum. In animal models of the disease, IFN-γ and TNF-α have been shown to play a central pathogenic role. In humans, unusually high concentrations of IL-18, an inducer of IFN-γ, and TNF-α have been reported, and are associated with an imbalance between IL-18 and its natural inhibitor IL-18 binding protein (IL-18BP) resulting in an excess of free IL-18. Here we studied whether IL-18BP could reduce disease severity in an animal model of HLH. Mouse cytomegalovirus infection in perforin-1 knock-out mice induced a lethal condition similar to human HLH characterized by cytopenia with marked inflammatory lesions in the liver and spleen as well as the presence of hemophagocytosis in bone marrow. IL-18BP treatment decreased hemophagocytosis and reversed liver as well as spleen damage. IL-18BP treatment also reduced both IFN-γ and TNF-α production by CD8(+) T and NK cells, as well as Fas ligand expression on NK cell surface. These data suggest that IL-18BP is beneficial in an animal model of HLH and in combination with anti-infectious therapy may be a promising strategy to treat HLH patients. 10.3389/fimmu.2012.00239
    Direct Reversible Kidney Injury in Familial Hemophagocytic Lymphohistiocytosis Type 3. Malaga-Dieguez Laura,Ming Wu,Trachtman Howard Journal of the American Society of Nephrology : JASN Hemophagocytic lymphohistiocytosis is a hyperinflammatory disorder resulting from primary or secondary immune dysfunction. AKI is frequent in severe hemophagocytic lymphohistiocytosis and has been attributed to multiorgan failure or the use of nephrotoxic drugs, but AKI is rarely considered a direct consequence of the disease process. We describe a child with familial hemophagocytic lymphohistiocytosis type 3 who developed AKI requiring prolonged renal replacement therapy because of severe renal inflammation. There was massive infiltration of the renal parenchyma by activated macrophages and cytotoxic T cells, and acute tubular injury. The patient responded to high-dose intravenous methylprednisolone, which resulted in improvement of renal function and discontinuation of renal replacement therapy. This case confirms the occurrence of reversible AKI due to hemophagocytic lymphohistiocytosis-induced activated macrophage infiltration of the renal parenchyma and inflammation. 10.1681/ASN.2014111090
    Hemophagocytic lymphohistiocytosis in SARS-CoV-2 infection. Dewaele Klaas,Claeys Rowan Blood 10.1182/blood.2020006505
    Urinary phagocytic macrophages in hemophagocytic lymphohistiocytosis. Oki Rikako,Kono Masanori,Kubo Kanae,Tojo Akihiro,Yamamoto Kazuhiko Kidney international 10.1016/j.kint.2016.07.023
    Distinct mutations in STXBP2 are associated with variable clinical presentations in patients with familial hemophagocytic lymphohistiocytosis type 5 (FHL5). Pagel Julia,Beutel Karin,Lehmberg Kai,Koch Florian,Maul-Pavicic Andrea,Rohlfs Anna-Katharina,Al-Jefri Abdullah,Beier Rita,Bomme Ousager Lilian,Ehlert Karoline,Gross-Wieltsch Ute,Jorch Norbert,Kremens Bernhard,Pekrun Arnulf,Sparber-Sauer Monika,Mejstrikova Ester,Wawer Angela,Ehl Stephan,zur Stadt Udo,Janka Gritta Blood Familial hemophagocytic lymphohistiocytosis (FHL) is a genetically determined hyperinflammatory syndrome caused by uncontrolled immune response mediated by T-lymphocytes, natural killer (NK) cells, and macrophages. STXBP2 mutations have recently been associated with FHL5. To better characterize the genetic and clinical spectrum of FHL5, we analyzed a cohort of 185 patients with suspected FHL for mutations in STXBP2. We detected biallelic mutations in 37 patients from 28 families of various ethnic origins. Missense mutations and mutations affecting 1 of the exon 15 splice sites were the predominant changes detectable in this cohort. Patients with exon 15 splice-site mutations (n = 13) developed clinical manifestations significantly later than patients with other mutations (median age, 4.1 year vs 2 months) and showed less severe impairment of degranulation and cytotoxic function of NK cells and CTLs. Patients with FHL5 showed several atypical features, including sensorineural hearing deficit, abnormal bleeding, and, most frequently, severe diarrhea that was only present in early-onset disease. In conclusion, we report the largest cohort of patients with FHL5 so far, describe an extended disease spectrum, and demonstrate for the first time a clear genotype-phenotype correlation. 10.1182/blood-2011-12-398958
    Contribution of clonal hematopoiesis to adult-onset hemophagocytic lymphohistiocytosis. Miller Peter G,Sperling Adam S,Gibson Christopher J,Viswanathan Kaushik,Castellano Cecilia,McConkey Marie,Ceremsak John,Taylor Martin S,Birndt Sebastian,Perner Florian,Arnason Jon,Agrawal Mridul,Schram Alison M,Nikiforow Sarah,Pihan German,Hasserjian Robert P,Aster Jon C,La Rosée Paul,Morgan Elizabeth A,Berliner Nancy,Ebert Benjamin L Blood Adult-onset hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disease of immune hyperactivation. Unlike pediatric HLH, adult HLH is rarely driven by germline genetic variants. Although numerous precipitating etiologies have been identified, the reason that HLH occurs in only a subset of individuals and how other factors contribute to the disease remains unknown. We hypothesized that clonal hematopoiesis (CH), a state in which somatic mutations in blood cells cause an expanded population of mutant hematopoietic cells and drive an aberrant inflammatory state, could contribute to adult-onset HLH. In a highly annotated cohort of older adults with HLH we found that CH was more prevalent than in control cohorts. Using the adult-onset HLH mouse model in which repeated treatments of the TLR9 agonist, ODN1826, was delivered to the mouse, we observed that macrophages carrying mutations in Tet2, one of the most commonly mutated genes in CH, have an enhanced inflammatory response to TLR9 agonism. Finally, mice carrying Tet2 mutations in the hematopoietic compartment (a common model for CH) displayed an exaggerated response to TLR9 agonism, including worse splenomegaly and anemia. Our data suggest that CH is more common in individuals with adult-onset HLH and can contribute to the pathophysiology of this disease. 10.1182/blood.2020008206
    Pediatric inborn errors of immunity causing hemophagocytic lymphohistiocytosis: Case report and review of the literature. Journal of leukocyte biology Inborn errors of immunity are a group of genetic disorders caused by mutations that affect the development and/or function of several compartments of the immune system, predisposing patients to infections, autoimmunity, allergy and malignancies. In this regard, mutations that affect proteins involved in trafficking, priming, docking, or membrane fusion will impair the exocytosis of lytic granules of effector NK and cytotoxic T lymphocytes. This may predispose patients to hemophagocytic lymphohistiocytosis, a life-threatening immune disorder characterized by systemic lymphocyte and macrophage activation, and increased levels of cytokines, which lead to an uncontrolled hyperinflammation state and progressive multiorgan damage. In this review, we will describe a clinical case and recent advances in inborn errors of immunity predisposing to hemophagocytic lymphohistiocytosis. Summary sentence: Review of recent advances in inborn errors of immunity predisposing to hemophagocytic lymphohistiocytosis. 10.1002/JLB.5MR0622-037R
    Hemophagocytic syndromes (HPSs) including hemophagocytic lymphohistiocytosis (HLH) in adults: A systematic scoping review. Hayden Anna,Park Sujin,Giustini Dean,Lee Agnes Y Y,Chen Luke Y C Blood reviews Most knowledge of hemophagocytic syndromes (HPSs) including hemophagocytic lymphohistiocytosis (HLH) is derived from pediatric studies; literature on adult HPS/HLH predominantly consists of small retrospective studies with clinical and methodological heterogeneity. The aims of this systematic scoping review were to provide an overview of existing literature on adult HPS/HLH, describe current practices in diagnosis and treatment, and propose priorities for future research. Articles from Ovid Medline, Embase and Pubmed (1975-2015) describing 10 or more unique adults (age>15years) with HPS/HLH were included. 82 publications were eligible: 10 were prospective and 72 were retrospective. Of the six distinct diagnostic criteria, the HLH-2004 criteria were by far the most commonly used. A minority of studies tested for genetic abnormalities (12), soluble interleukin-2 receptor (11), and/or NK function (11) in a subset of patients. Most centers used steroids and either etoposide-based (HLH-94/HLH-2004) or doxorubicin-based (CHOP) initial therapy regimens. Allogeneic hematopoietic cell therapy for treatment of adult HLH has rarely been reported. Mortality in larger treatment focused studies ranged from 20 to 88%. Developing adult-specific diagnostic criteria based on widely evaluable features of secondary HPS/HLH and establishing standard initial therapies are priorities for future research. 10.1016/j.blre.2016.05.001
    Subtle differences in CTL cytotoxicity determine susceptibility to hemophagocytic lymphohistiocytosis in mice and humans with Chediak-Higashi syndrome. Jessen Birthe,Maul-Pavicic Andrea,Ufheil Heike,Vraetz Thomas,Enders Anselm,Lehmberg Kai,Längler Alfred,Gross-Wieltsch Ute,Bay Ali,Kaya Zuhre,Bryceson Yenan T,Koscielniak Ewa,Badawy Sherif,Davies Graham,Hufnagel Markus,Schmitt-Graeff Annette,Aichele Peter,Zur Stadt Udo,Schwarz Klaus,Ehl Stephan Blood Perforin-mediated cytotoxicity is important for controlling viral infections, but also for limiting immune reactions. Failure of this cytotoxic pathway leads to hemophagocytic lymphohistiocytosis (HLH), a life-threatening disorder of uncontrolled T-cell and macrophage activation. We studied susceptibility to HLH in 2 mouse strains (souris and beige(J)) and a cohort of patients with partial defects in perforin secretion resulting from different mutations in the LYST gene. Although both strains lacked NK-cell cytotoxicity, only souris mice developed all clinical and histopathologic signs of HLH after infection with lymphocytic choriomeningitis virus. The 2 strains showed subtle differences in CTL cytotoxicity in vitro that had a large impact on virus control in vivo. Whereas beige(J) CTLs eliminated lymphocytic choriomeningitis virus infection, souris CTLs failed to control the virus, which was associated with the development of HLH. In LYST-mutant patients with Chediak-Higashi syndrome, CTL cytotoxicity was reduced in patients with early-onset HLH, whereas it was retained in patients who later or never developed HLH. Thus, the risk of HLH development is set by a threshold that is determined by subtle differences in CTL cytotoxicity. Differences in the cytotoxic capacity of CTLs may be predictive for the risk of Chediak-Higashi syndrome patients to develop HLH. 10.1182/blood-2011-05-356113
    Serum soluble VSIG4 as a surrogate marker for the diagnosis of lymphoma-associated hemophagocytic lymphohistiocytosis. Yuan Shunzong,Wang Yanqing,Luo Hui,Jiang Zheng,Qiao Bing,Jiang Yan,Hu Yaning,Cheng Yang,Chen Xilin,Gong Weihua,Huang Yong,Zhao Weipeng,Luo Deyan,Liu Bing,Su Hang,Zhou Jianfeng,Song Shiping British journal of haematology Lymphoma-associated haemophagocytic lymphohistiocytosis (L-HLH) is characterized by excessively activated macrophages and cytotoxic T lymphocytes, but few reliable markers for activated macrophages are available clinically. This study, designed to discover novel biomarkers for the diagnosis of lymphoma patients with L-HLH, was initiated between 2016 and 2018. Fifty-seven adult lymphoma patients were enrolled - 39 without HLH and 18 with HLH. The differential serum protein expression profile was first screened between lymphoma patients with and without L-HLH by a quantitative mass spectrometric approach. Soluble V-set and immunoglobulin domain-containing 4 (sVSIG4), specifically expressed by macrophages, was significantly upregulated in the L-HLH group. Subsequently, sVSIG4 concentration was confirmed by enzyme-linked immunosorbent assay to be significantly increased in lymphoma patients with L-HLH. When it was exploited for the diagnosis of lymphoma patients with L-HLH, the area under a receiver operating characteristic curve was 0·98 with an optimal cut-off point of 2195 pg/ml and the corresponding sensitivity and specificity were 94·44% and 94·87% respectively. In addition, the one-year overall survival was significantly worse in patients with a sVSIG4 concentration above 2195 pg/ml compared with those below 2195 pg/ml (5·3% vs. 72·2%, P < 0·0001). sVSIG4 may be a surrogate marker of activated macrophages for the diagnosis of lymphoma patients with L-HLH. 10.1111/bjh.16299
    Familial hemophagocytic lymphohistiocytosis: a model for understanding the human machinery of cellular cytotoxicity. Cellular and molecular life sciences : CMLS Cytotoxic T lymphocytes, natural killer cells, and NKT cells are effector cells able to kill infected cells. In some inherited human disorders, a defect in selected proteins involved in the cellular cytotoxicity mechanism results in specific clinical syndromes, grouped under the name of familial hemophagocytic lymphohistiocytosis. Recent advances in genetic studies of these patients has allowed the identification of different genetic subsets. Additional genetic immune deficiencies may also induce a similar clinical picture. International cooperation and prospective trials resulted in refining the diagnostic and therapeutic approach to these rare diseases with improved outcome but also with improved knowledge of the mechanisms underlying granule-mediated cellular cytotoxicity in humans. 10.1007/s00018-011-0835-y
    COVID-19-associated cytokine storm syndrome and diagnostic principles: an old and new Issue. Yongzhi Xi Emerging microbes & infections SARS-CoV-2 has claimed 2,137,908 lives in more than a year. Some COVID-19 patients experience sudden and rapid deterioration with the onset of fatal cytokine storm syndrome (CSS), which have increased interest in CSS's mechanisms, diagnosis and therapy. Although the prototypic concept of CSS was first proposed 116 years ago, we have only begun to study and understand CSS for less than 30 years. Actually, diseases under CSS umbrella include familial/primary and secondary hemophagocytic lymphohistiocytosis (HLH), macrophage activation syndrome (MAS), infection-associated hemophagocytic syndrome, cytokine release syndrome (CRS), and cytokine storm (CS). Hematologic malignancies and autoimmune diseases that cause CSS are named malignancy-associated hemophagocytic syndrome (MAHS) and MAS, respectively. In-depth research on the pathogenesis of HLH/CSS has greatly increased the number of patients that were able to be definitively diagnosed with HLH/CSS. However, it should be emphasized that HLH/CSS diagnosis is difficult at the early stages due to the non-specific clinical signs and symptoms, which tends to result in missed and incorrect diagnoses. Therefore, clinicians should not only possess extensive clinical experience to ensure high sensitivity to the characteristics of HLH/CSS but must also be familiar with HLH-2004/2009 diagnostic criteria, and HScore methods. The paper concisely comment evolution of CSS classifications, cytokines associated with CSS, evolution of CSS diagnostic criteria and importance of the correct identification of hemophagocytes in diagnosing CSS, which is timely and may benefit clinicians familiar HLH-2004/2009 diagnostic criteria, and HScore methods. In addition, clinicians must also understand that there are some limitations to these diagnostic criteria. Abbreviations: aBMT: autologous bone marrow transplantation; CAR-T: chimeric antigen receptor-engineered T-cell; COVID-19: coronavirus disease 2019; CSS: cytokine storm syndrome; HLH: hemophagocytic lymphohistiocytosis; MAS: macrophage activation syndrome; CRS: cytokine release syndrome; CS: cytokine storm; MAHS: malignancy-associated hemophagocytic syndrome; IAHS: infection-associated hemophagocytic syndrome; fHLH/pHLH: familial/primary hemophagocytic lymphohistiocytosis; sHLH: secondary hemophagocytic lymphohistiocytosis; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; TCR-T, T-cell receptor-engineered T-cell. 10.1080/22221751.2021.1884503
    Prognostic Value of Blood-Based Inflammatory Biomarkers in Secondary Hemophagocytic Lymphohistiocytosis. Huang Jiayu,Yin Guangli,Duan Limin,Tian Tian,Xu Ji,Wang Jujuan,Gao Xin,Cheng Wanying,Liu Lingling,Qiu Hongxia Journal of clinical immunology PURPOSE:Hemophagocytic lymphohistiocytosis (HLH) is a rare systematic immune disease manifested with excessive activation of lymphocytes and macrophages. This study was designed to explore the feasible prognostic factors of secondary HLH (sHLH). METHOD:We retrospectively analyzed 179 patients with newly diagnosed sHLH from January 2016 to May 2019 according to the HLH-2004 protocol. Baseline characteristics and laboratory results were reviewed. RESULTS:The median age of all patients was 53 years, with a male/female ratio of 1.45. The commonest cause of HLH was malignancy. Of the 179 patients, 48.6% presented with Epstein-Barr virus (EBV) infection, 92.8% with hemocytopenia (at least 2 lineages), 60.3% with hypofibrinogenemia, 43.0% with hypertriglyceridemia (≥ 3 mmol/L), 99.4% with high ferritin, 97.8% with fever, 72.1% with splenomegaly, and 72.6% with hemophagocytosis. As to their prognosis, 122 patients died; the median survival was 88 days, with a 2-year survival rate of 26.72%. Univariate analysis confirmed neutrophil-to-lymphocyte ratio ˃ 2.53, lymphocyte-to-monocyte ratio (LMR) ≤ 4.43, platelet-to-lymphocyte ratio ˃ 227.27, red blood cell distribution width ˃ 14.6, red blood cell distribution width-to-platelet ratio (RPR) > 0.33, EBV infection, platelet ≤ 34 × 10 /L, fibrinogen ≤ 1.34 g/L, alkaline phosphatase ˃ 182.4 U/L, adenosine deaminase ˃ 69.2 U/L, and ferritin ˃ 2318 ng/mL were associated with an inferior survival. In a multivariate model, LMR, RPR, and ferritin were considered as three independent factors. CONCLUSION:Some blood-based inflammatory markers, which can be easily and cheaply detected, are significantly associated with the OS of HLH patients. LMR and RPR, superior to NLR, PLR, RDW, can be taken to predict the OS of patients with HLH. 10.1007/s10875-020-00801-x
    Hemophagocytic Syndrome With Histiocytic Glomerulopathy and Intraglomerular Hemophagocytosis. Santoriello Dominick,Hogan Jonathan,D'Agati Vivette D American journal of kidney diseases : the official journal of the National Kidney Foundation Hemophagocytic syndrome (HPS), a rare and life-threatening disease, is characterized by hyperactivation of the immune system that causes hypercytokinemia and potential multiorgan failure. Acute kidney injury is the most common kidney manifestation of HPS and is generally considered a poor prognostic factor. Glomerular involvement is uncommon and usually manifests as either podocytopathy with collapsing glomerulopathy or thrombotic microangiopathy. We report a rare case of severe histiocytic glomerulopathy in a patient with HPS who presented with acute kidney injury and proteinuria. Kidney biopsy revealed massive glomerular infiltration by macrophages resembling proliferative glomerulonephritis accompanied by intraglomerular hemophagocytosis and mild features of glomerular thrombotic microangiopathy. The patient's kidney failure and proteinuria responded rapidly to high-dose pulse methylprednisolone followed by a tapering course of oral prednisone. Our case expands the renal pathologic spectrum of HPS to include histiocyte-rich glomerular infiltration and intraglomerular hemophagocytosis. Greater awareness of this entity is needed to ensure prompt recognition and appropriate therapy. 10.1053/j.ajkd.2015.11.017
    Hemophagocytic lymphohistiocytosis after SARS-CoV-2 vaccination. Hieber Marie-Lisa,Sprute Rosanne,Eichenauer Dennis A,Hallek Michael,Jachimowicz Ron D Infection PURPOSE:The coronavirus disease 2019 (COVID-19) pandemic has led to the approval of novel vaccines with different mechanisms of action. Until now, more than 4.7 billion persons have been vaccinated around the world, and adverse effects not observed in pre-authorization trials are being reported at low frequency. METHODS:We report a case of severe hemophagocytic lymphohistiocytosis (HLH) after SARS-CoV-2 immunization and performed a literature search for all reported cases of COVID-19 vaccine-associated HLH. RESULTS:A 24-year-old female developed HLH after immunization with the mRNA COVID-19 vaccine Comirnaty. Diagnosis was made according to HLH-2004 criteria; the HScore was 259 (> 99% HLH probability) with maximum ferritin of 138.244 µg/L. The patient was initially treated with intravenous immunoglobulins (IVIGs) and dexamethasone without response. The addition of the human interleukin 1 receptor antagonist Anakinra resulted in full recovery within 6 weeks after vaccination. A literature search revealed 15 additional cases of HLH after SARS-CoV-2 vaccination, the majority after immunization with Comirnaty (n = 7) or the viral vector vaccine Vaxzevria (n = 6). Treatment modalities included corticosteroids (n = 13), Anakinra (n = 5), IVIGs (n = 5), and etoposide (n = 2). Eight patients underwent combination treatment. Three of 16 patients died. CONCLUSION:COVID-19 vaccines may occasionally trigger HLH, and Anakinra may be an efficacious treatment option for this condition. 10.1007/s15010-022-01786-y
    How Viruses Contribute to the Pathogenesis of Hemophagocytic Lymphohistiocytosis. Brisse Ellen,Wouters Carine H,Andrei Graciela,Matthys Patrick Frontiers in immunology Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening, hyperinflammatory syndrome, characterized by the uncontrolled activation of macrophages and T cells, eliciting key symptoms such as persistent fever, hepatosplenomegaly, pancytopenia, hemophagocytosis, hyperferritinemia, and coagulopathy. Viral infections are frequently implicated in the onset of active HLH episodes, both in primary, genetic HLH as in the secondary, acquired form. Infections with herpesviruses such as Epstein-Barr virus and cytomegalovirus are the most common. In autoimmune diseases, a link between viral infections and autoreactive immune responses has been recognized for a considerable time. However, the mechanisms by which viruses contribute to HLH pathogenesis remain to be clarified. In this viewpoint, different factors that may come into play are discussed. Viruses, particularly larger DNA viruses such as herpesviruses, are potent modulators of the immune response. By evading immune recognition, interfering with cytokine balances and inhibiting apoptotic pathways, viruses may increase the host's susceptibility to HLH development. In particular cases, a direct connection between the viral infection and inhibition of natural killer cell or T cell cytotoxicity was reported, indicating that viruses may create immunological deficiencies reminiscent of primary HLH. 10.3389/fimmu.2017.01102
    Hemophagocytic syndrome: primary forms and predisposing conditions. Sepulveda Fernando E,de Saint Basile Geneviève Current opinion in immunology Hemophagocytic lymphohistiocytosis (HLH, also referred to a hemophagocytic syndrome) is a life-threatening condition in which uncontrolled activation of lymphocytes and macrophages, and thus the secretion of large amounts of inflammatory cytokines, leads to a severe hyperinflammatory state. Over the last few decades, researchers have characterized primary forms of HLH caused by genetic defects that impair lymphocytes' cytotoxic machinery. Other genetic causes of HLH not related to impaired cytotoxicity have also recently been identified. Furthermore, the so-called 'acquired' forms of HLH are encountered in the context of severe infections, autoimmune and autoinflammatory diseases, malignancy, and metabolic disorders, and may also be associated with primary immunodeficiencies. This implies that a variety of disease mechanisms can lead to HLH. Today's research seeks to gain a better understanding of the various pathogenetic and environmental factors that converge to induce HLH. 10.1016/j.coi.2017.08.004
    Severe mycobacterial IRIS in advanced HIV has features of hemophagocytic lymphohistiocytosis and requires prolonged immune suppression. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America BACKGROUND:People with HIV and mycobacterial infections can develop immune reconstitution inflammatory syndrome (IRIS) after starting antiretroviral therapy. Severe mycobacterial-IRIS has an overlapping clinical phenotype with hemophagocytic lymphohistiocytosis (HLH). OBJECTIVE:To evaluate the pathophysiologic similarities between mycobacterial-IRIS and HLH and identify clinical and immune predictors of mycobacterial-IRIS severity. METHODS:HLH-criteria were applied to a longitudinal cohort of 80-patients with HIV (CD4 < 100 cells/µL) and mycobacterial infections. Participants were subdivided into IRIS meeting HLH-criteria (HLH-IRIS), IRIS without HLH (IRIS), and those without IRIS (Non-IRIS). Clinical outcomes were evaluated by regression analyses. Soluble biomarkers and T-cell immune phenotypes were assessed at baseline and IRIS-equivalent timepoints. RESULTS:HLH-IRIS patients required corticosteroids more frequently (OR 21.5 [CI95% 5.6-114.8]) and for longer duration (21.2-weeks [CI95% 10.7-31.7]) than those not meeting HLH-criteria. Utilizing decision tree analyses, hemoglobin <9.2  g/dL was the best predictor of HLH-IRIS before antiretroviral treatment, whereas ferritin and immune markers (CXCL-9, sCD25) were most diagnostic for HLH at onset of IRIS. At the IRIS-timepoint, but not baseline, HLH-IRIS patients had lower regulatory and higher activated T-cells along with greater production of IFNγ-IL18 axis biomarkers compared to both IRIS and Non-IRIS groups. Principal component analysis corroborated the distinct clustering of HLH-IRIS patients. CONCLUSION:Severe mycobacterial-IRIS and HLH have an overlapping pathogenesis involving IFNγ and unopposed T-cell activation causing severe inflammatory disease clinically distinguished by hyperferritinemia (hyperferritinemic IRIS or FIRIS). Hemoglobin, ferritin, CXCL-9, and sCD25 identify this high-risk population and may improve risk stratification and therapeutic strategies for mycobacterial-IRIS. 10.1093/cid/ciac717
    Benefit of Anakinra in Treating Pediatric Secondary Hemophagocytic Lymphohistiocytosis. Eloseily Esraa M,Weiser Peter,Crayne Courtney B,Haines Hilary,Mannion Melissa L,Stoll Matthew L,Beukelman Timothy,Atkinson T Prescott,Cron Randy Q Arthritis & rheumatology (Hoboken, N.J.) OBJECTIVE:To assess the benefit of the recombinant human interleukin-1 receptor antagonist anakinra in treating pediatric patients with secondary hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) associated with rheumatic and nonrheumatic conditions. METHODS:A retrospective chart review of all anakinra-treated patients with secondary HLH/MAS was performed at Children's of Alabama from January 2008 through December 2016. Demographic, clinical, laboratory, and genetic characteristics, outcomes data, and information on concurrent treatments were collected from the records and analyzed using appropriate univariate statistical approaches to assess changes following treatment and associations between patient variables and outcomes. RESULTS:Forty-four patients with secondary HLH/MAS being treated with anakinra were identified in the electronic medical records. The median duration of hospitalization was 15 days. The mean pretreatment serum ferritin level was 33,316 ng/ml and dropped to 14,435 ng/ml (57% decrease) within 15 days of the start of anakinra treatment. The overall mortality rate in the cohort was 27%. Earlier initiation of anakinra (within 5 days of hospitalization) was associated with reduced mortality (P = 0.046), whereas thrombocytopenia (platelet count <100,000/μl) and STXBP2 mutations were both associated with increased mortality (P = 0.008 and P = 0.012, respectively). In considering patients according to their underlying diagnosis, those with systemic juvenile idiopathic arthritis (JIA) had the lowest mortality rate, with no deaths among the 13 systemic JIA patients included in the study (P = 0.006). In contrast, those with an underlying hematologic malignancy had the highest mortality rate, at 100% (n = 3). CONCLUSION:These findings suggest that anakinra appears to be effective in treating pediatric patients with non-malignancy-associated secondary HLH/MAS, especially when it is given early in the disease course and when administered to patients who have an underlying rheumatic disease. 10.1002/art.41103
    Whole-exome sequencing reveals overlap between macrophage activation syndrome in systemic juvenile idiopathic arthritis and familial hemophagocytic lymphohistiocytosis. Kaufman Kenneth M,Linghu Bolan,Szustakowski Joseph D,Husami Ammar,Yang Fan,Zhang Kejian,Filipovich Alexandra H,Fall Ndate,Harley John B,Nirmala N R,Grom Alexei A Arthritis & rheumatology (Hoboken, N.J.) OBJECTIVE:Macrophage activation syndrome (MAS), a life-threatening complication of systemic juvenile idiopathic arthritis (JIA), resembles familial hemophagocytic lymphohistiocytosis (HLH), a constellation of autosomal-recessive immune disorders resulting from deficiency in cytolytic pathway proteins. We undertook this study to test our hypothesis that MAS predisposition in systemic JIA could be attributed to rare gene sequence variants affecting the cytotolytic pathway. METHODS:Whole-exome sequencing was used in 14 patients with systemic JIA and MAS and in their parents to identify protein-altering single-nucleotide polymorphisms/indels in known HLH-associated genes. To discover new candidate genes, the entire whole-exome sequencing data were filtered to identify protein-altering, rare recessive homozygous, compound heterozygous, and de novo variants with the potential to affect the cytolytic pathway. RESULTS:Heterozygous protein-altering rare variants in the known genes (LYST,MUNC13-4, and STXBP2) were found in 5 of 14 patients with systemic JIA and MAS (35.7%). This was in contrast to only 4 variants in 4 of 29 patients with systemic JIA without MAS (13.8%). Homozygosity and compound heterozygosity analysis applied to the entire whole-exome sequencing data in systemic JIA/MAS revealed 3 recessive pairs in 3 genes and compound heterozygotes in 73 genes. We also identified 20 heterozygous rare protein-altering variants that occurred in at least 2 patients. Many of the identified genes encoded proteins with a role in actin and microtubule reorganization and vesicle-mediated transport. "Cellular assembly and organization" was the top cellular function category based on Ingenuity Pathways Analysis (P < 3.10 × 10(-5) ). CONCLUSION:Whole-exome sequencing performed in patients with systemic JIA and MAS identified rare protein-altering variants in known HLH-associated genes as well as in new candidate genes. 10.1002/art.38793
    Hemophagocytic lymphohistiocytosis (HLH): A heterogeneous spectrum of cytokine-driven immune disorders. Brisse Ellen,Wouters Carine H,Matthys Patrick Cytokine & growth factor reviews Hemophagocytic lymphohistiocytosis (HLH) comprises a group of life-threatening immune disorders classified into primary or secondary HLH. The former is caused by mutations in genes involved in granule-mediated cytotoxicity, the latter occurs in a context of infections, malignancies or autoimmune/autoinflammatory disorders. Both are characterized by systemic inflammation, severe cytokine storms and immune-mediated organ damage. Despite recent advances, the pathogenesis of HLH remains incompletely understood. Animal models resembling different subtypes of HLH are therefore of great value to study this disease and to uncover novel treatment strategies. In this review, all known animal models of HLH will be discussed, highlighting findings on cell types, cytokines and signaling pathways involved in disease pathogenesis and extrapolating therapeutic implications for the human situation. 10.1016/j.cytogfr.2014.10.001
    Specific sequences of infectious challenge lead to secondary hemophagocytic lymphohistiocytosis-like disease in mice. Wang Andrew,Pope Scott D,Weinstein Jason S,Yu Shuang,Zhang Cuiling,Booth Carmen J,Medzhitov Ruslan Proceedings of the National Academy of Sciences of the United States of America Secondary hemophagocytic lymphohistiocytosis (sHLH) is a highly mortal complication associated with sepsis. In adults, it is often seen in the setting of infections, especially viral infections, but the mechanisms that underlie pathogenesis are unknown. sHLH is characterized by a hyperinflammatory state and the presence hemophagocytosis. We found that sequential challenging of mice with a nonlethal dose of viral toll-like receptor (TLR) agonist followed by a nonlethal dose of TLR4 agonist, but not other permutations, produced a highly lethal state that recapitulates many aspects of human HLH. We found that this hyperinflammatory response could be recapitulated in vitro in bone marrow-derived macrophages. RNA sequencing analyses revealed dramatic up-regulation of the red-pulp macrophage lineage-defining transcription factor SpiC and its associated transcriptional program, which was also present in bone marrow macrophages sorted from patients with sHLH. Transcriptional profiling also revealed a unique metabolic transcriptional profile in these macrophages, and immunometabolic phenotyping revealed impaired mitochondrial function and oxidative metabolism and a reliance on glycolytic metabolism. Subsequently, we show that therapeutic administration of the glycolysis inhibitor 2-deoxyglucose was sufficient to rescue animals from HLH. Together, these data identify a potential mechanism for the pathogenesis of sHLH and a potentially useful therapeutic strategy for its treatment. 10.1073/pnas.1820704116
    Excessive IL-10 and IL-18 trigger hemophagocytic lymphohistiocytosis-like hyperinflammation and enhanced myelopoiesis. The Journal of allergy and clinical immunology BACKGROUND:Hyperinflammation is a life-threatening condition associated with various clinical disorders characterized by excessive immune activation and tissue damage. Multiple cytokines promote the development of hyperinflammation; however, the contribution of IL-10 remains unclear despite emerging speculations for a pathological role. Clinical observations from hemophagocytic lymphohistiocytosis (HLH), a prototypical hyperinflammatory disease, suggest that IL-18 and IL-10 may collectively promote the onset of a hyperinflammatory state. OBJECTIVE:We aimed to investigate the collaborative roles of IL-10 and IL-18 in hyperinflammation. METHODS:A comprehensive plasma cytokine profile for 87 secondary HLH patients was first depicted and analyzed. We then investigated the systemic and cellular effects of coelevated IL-10 and IL-18 in a transgenic mouse model and cultured macrophages. Single-cell RNA sequencing was performed on the monocytes/macrophages isolated from secondary HLH patients to explore the clinical relevance of IL-10/IL-18-mediated cellular signatures. The therapeutic efficacy of IL-10 blockade was tested in HLH mouse models. RESULTS:Excessive circulating IL-10 and IL-18 triggered a lethal hyperinflammatory disease recapitulating HLH-like phenotypes in mice, driving peripheral lymphopenia and a striking shift toward enhanced myelopoiesis in the bone marrow. IL-10 and IL-18 polarized cultured macrophages to a distinct proinflammatory state with pronounced expression of myeloid cell-recruiting chemokines. Transcriptional characterization suggested the IL-10/IL-18-mediated cellular features were clinically relevant with HLH, showing enhanced granzyme expression and proteasome activation in macrophages. IL-10 blockade protected against the lethal disease in HLH mouse models. CONCLUSION:Coelevated IL-10 and IL-18 are sufficient to drive HLH-like hyperinflammatory syndrome, and blocking IL-10 is protective in HLH models. 10.1016/j.jaci.2022.06.017
    Senescence-accelerated mice (SAMP1/TA-1) treated repeatedly with lipopolysaccharide develop a condition that resembles hemophagocytic lymphohistiocytosis. Tsuboi Isao,Harada Tomonori,Hirabayashi Yoko,Aizawa Shin Haematologica Hemophagocytic lymphohistiocytosis is a life-threatening systemic hyperinflammatory disorder with primary and secondary forms. Primary hemophagocytic lymphohistiocytosis is associated with inherited defects in various genes that affect the immunological cytolytic pathway. Secondary hemophagocytic lymphohistiocytosis is not inherited, but complicates various medical conditions including infections, autoinflammatory/autoimmune diseases, and malignancies. When senescence-accelerated mice (SAMP1/TA-1) with latent deterioration of immunological function and senescence-resistant control mice (SAMR1) were treated repeatedly with lipopolysaccharide, SAMP1/TA-1 mice displayed the clinicopathological features of hemophagocytic lymphohistiocytosis such as hepatosplenomegaly, pancytopenia, hypofibrinogenemia, hyperferritinemia, and hemophagocytosis. SAMR1 mice showed no features of hemophagocytic lymphohistiocytosis. Lipopolysaccharide induced upregulation of proinflammatory cytokines such as interleukin-1β, interleukin-6, tumor necrosis factor-α, and interferon-γ, and interferon-γ-inducible chemokines such as c-x-c motif chemokine ligands 9 and 10 in the liver and spleen in both SAMP1/TA-1 and SAMR1 mice. However, upregulation of proinflammatory cytokines and interferon-γ-inducible chemokines in the liver persisted for longer in SAMP1/TA-1 mice than in SAMR1 mice. In addition, the magnitude of upregulation of interferon-γ in the liver and spleen after lipopolysaccharide treatment was greater in SAMP1/TA-1 mice than in SAMR1 mice. Furthermore, lipopolysaccharide treatment led to a prolonged increase in the proportion of peritoneal M1 macrophages and simultaneously to a decrease in the proportion of M2 macrophages in SAMP1/TA-1 mice compared with SAMR1 mice. Lipopolysaccharide appeared to induce a hyperinflammatory reaction and prolonged inflammation in SAMP1/TA-1 mice, resulting in features of secondary hemophagocytic lymphohistiocytosis. Thus, SAMP1/TA-1 mice represent a useful mouse model to investigate the pathogenesis of bacterial infection-associated secondary hemophagocytic lymphohistiocytosis. 10.3324/haematol.2018.209551
    Recurrent ECSIT mutation encoding V140A triggers hyperinflammation and promotes hemophagocytic syndrome in extranodal NK/T cell lymphoma. Wen Haijun,Ma Huajuan,Cai Qichun,Lin Suxia,Lei Xinxing,He Bin,Wu Sijin,Wang Zifeng,Gao Yan,Liu Wensheng,Liu Weiping,Tao Qian,Long Zijie,Yan Min,Li Dali,Kelley Keith W,Yang Yongliang,Huang Huiqiang,Liu Quentin Nature medicine Hemophagocytic syndrome (HPS) is a fatal hyperinflammatory disease with a poorly understood mechanism that occurs most frequently in extranodal natural killer/T cell lymphoma (ENKTL). Through exome sequencing of ENKTL tumor-normal samples, we have identified a hotspot mutation (c.419T>C) in the evolutionarily conserved signaling intermediate in Toll pathway (ECSIT) gene, encoding a V140A variant of ECSIT. ECSIT-V140A activated NF-κB more potently than the wild-type protein owing to its increased affinity for the S100A8 and S100A9 heterodimer, which promotes NADPH oxidase activity. ECSIT-T419C knock-in mice showed higher peritoneal NADPH oxidase activity than mice with wild-type ECSIT in response to LPS. ECSIT-T419C-transfected ENKTL cell lines produced tumor necrosis factor (TNF)-α and interferon (IFN)-γ, which induced macrophage activation and massive cytokine secretion in cell culture and mouse xenografts. In individuals with ENKTL, ECSIT-V140A was associated with activation of NF-κB, higher HPS incidence, and poor prognosis. The immunosuppressive drug thalidomide prevented NF-κB from binding to the promoters of its target genes (including TNF and IFNG), and combination treatment with thalidomide and dexamethasone extended survival of mice engrafted with ECSIT-T419C-transfected ENKTL cells. We added thalidomide to the conventional dexamethasone-containing therapy regimen for two patients with HPS who expressed ECSIT-V140A, and we observed reversal of their HPS and disease-free survival for longer than 3 years. These findings provide mechanistic insights and a potential therapeutic strategy for ENKTL-associated HPS. 10.1038/nm.4456
    Whole-Exome Sequencing Reveals Mutations in Genes Linked to Hemophagocytic Lymphohistiocytosis and Macrophage Activation Syndrome in Fatal Cases of H1N1 Influenza. Schulert Grant S,Zhang Mingce,Fall Ndate,Husami Ammar,Kissell Diane,Hanosh Andrew,Zhang Kejian,Davis Kristina,Jentzen Jeffrey M,Napolitano Lena,Siddiqui Javed,Smith Lauren B,Harms Paul W,Grom Alexei A,Cron Randy Q The Journal of infectious diseases BACKGROUND:Severe H1N1 influenza can be lethal in otherwise healthy individuals and can have features of reactive hemophagocytic lymphohistiocytosis (HLH). HLH is associated with mutations in lymphocyte cytolytic pathway genes, which have not been previously explored in H1N1 influenza. METHODS:Sixteen cases of fatal influenza A(H1N1) infection, 81% with histopathologic hemophagocytosis, were identified and analyzed for clinical and laboratory features of HLH, using modified HLH-2004 and macrophage activation syndrome (MAS) criteria. Fourteen specimens were subject to whole-exome sequencing. Sequence alignment and variant filtering detected HLH gene mutations and potential disease-causing variants. Cytolytic function of the PRF1 p.A91V mutation was tested in lentiviral-transduced NK-92 natural killer (NK) cells. RESULTS:Despite several lacking variables, cases of influenza A(H1N1) infection met 44% and 81% of modified HLH-2004 and MAS criteria, respectively. Five subjects (36%) carried one of 3 heterozygous LYST mutations, 2 of whom also possessed the p.A91V PRF1 mutation, which was shown to decrease NK cell cytolytic function. Several patients also carried rare variants in other genes previously observed in MAS. CONCLUSIONS:This cohort of fatal influenza A(H1N1) infections confirms the presence of hemophagocytosis and HLH pathology. Moreover, the high percentage of HLH gene mutations suggests they are risk factors for mortality among individuals with influenza A(H1N1) infection. 10.1093/infdis/jiv550
    Posttransplant Hemophagocytic Lymphohistiocytosis Driven by Myeloid Cytokines and Vicious Cycles of T-Cell and Macrophage Activation in Humanized Mice. Yoshihara Satoshi,Li Yuying,Xia Jinxing,Danzl Nichole,Sykes Megan,Yang Yong-Guang Frontiers in immunology Hemophagocytic lymphohistiocytosis (HLH) has recently been increasingly reported as an important complication after stem cell transplantation, in line with the increase in the number of HLA-mismatched transplantation. Although previous clinical studies have shown an elevation of inflammatory cytokines in patients with HLH after hematopoietic stem cell transplantation, as well as those after viral infection or autoimmune disease, the disease pathogenesis remains poorly understood. Here we explored this issue in humanized mice with functional human lymphohematopoietic systems, which were constructed by transplantation of human CD34 cells alone, or along with human fetal thymus into NOD/SCID/γc (NSG) or NSG mice carrying human SCF/GM-CSF/IL-3 transgenes (SGM3). In comparison with humanized NSG (huNSG) mice, huSGM3 mice had higher human myeloid reconstitution and aggressive expansion of human CD4 memory T cells, particularly in the absence of human thymus. Although all huNSG mice appeared healthy throughout the observation period of over 20 weeks, huSGM3 mice developed fatal disease characterized by severe human T cell and macrophage infiltrations to systemic organs. HuSGM3 mice also showed severe anemia and thrombocytopenia with hypoplastic bone marrow, but increased reticulocyte counts in blood. In addition, huSGM3 mice showed a significant elevation in human inflammatory cytokines including IL-6, IL-18, IFN-α, and TNF-γ, faithfully reproducing HLH in clinical situations. Our study suggests that posttransplant HLH is triggered by alloresponses (or xenoresponses in our model), driven by myeloid cytokines, and exacerbated by vicious cycles of T-cell and macrophage activation. 10.3389/fimmu.2019.00186
    E-cigarette or Vaping-Associated Acute Lung Injury and Hemophagocytic Lymphohistiocytosis. Derespina Kim R,Kaushik Shubhi,Mitchell William,Gorstein Samuel,Ushay H Michael,Medar Shivanand S Pediatrics In this report, we describe the case of a 17-year-old boy with progressive respiratory failure requiring extracorporeal support who met clinical criteria for a presumptive diagnosis of electronic cigarette or vaping-associated acute lung injury (EVALI), with clinical, pathologic, and laboratory evidence of hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS). The patient in our report had a history of tetrahydrocannabinol and nicotine electronic cigarette use for months leading up to his presentation of fever, headache, emesis, and weight loss with respiratory distress. Multiple potential diagnoses were explored, and the patient's respiratory status improved, and he was initially discharged from the hospital. Roughly one week later, the patient was readmitted for worsening respiratory distress. The patient then met sufficient criteria for a potential diagnosis of HLH and MAS (elevated ferritin level, inflammatory markers, and cytopenia) to warrant a bone marrow aspirate, which revealed rare hemophagocytic cells. Given the severity of his symptoms and laboratory evidence of HLH and MAS, the patient was started on a course of steroids and anakinra. Although laboratory markers improved after treatment, the patient's respiratory failure worsened, ultimately progressing to a need for mechanical ventilation and extracorporeal support and leading to worsening multiorgan system failure and, ultimately, death. To the best of our knowledge, this is the first report of a patient with a presumptive diagnosis of EVALI with evidence of HLH and MAS, raising the possibility that macrophage activation may play a role in the pathogenesis of EVALI. 10.1542/peds.2019-3664
    Hemophagocytic syndrome in patients with acute myeloid leukemia undergoing intensive chemotherapy. Delavigne Karen,Bérard Emilie,Bertoli Sarah,Corre Jill,Duchayne Eliane,Demur Cécile,Mansat-De Mas Véronique,Borel Cécile,Picard Muriel,Alvarez Muriel,Sarry Audrey,Huguet Françoise,Récher Christian Haematologica Hemophagocytic lymphohistiocytosis is a condition of immune dysregulation characterized by severe organ damage induced by a hyperinflammatory response and uncontrolled T-cell and macrophage activation. Secondary hemophagocytic lymphohistiocytosis typically occurs in association with severe infections or malignancies. Patients with acute myeloid leukemia may be prone to develop hemophagocytic lymphohistiocytosis because of an impaired immune response and a high susceptibility to severe infections. In a series of 343 patients treated by intensive chemotherapy over a 5-year period in our center, we identified 32 patients (9.3%) with fever, very high ferritin levels, and marrow hemophagocytosis (i.e. patients with hemophagocytic lymphohistiocytosis). Compared to patients without hemophagocytic lymphohistiocytosis, these 32 patients had hepatomegaly, pulmonary or neurological symptoms, liver abnormalities, lower platelet count and higher levels of C-reactive protein as well as prolonged pancytopenia. A microbial etiology for the hemophagocytosis was documented in 24 patients: 14 bacterial infections, 9 Herpesviridae infections and 11 fungal infections. The treatment of hemophagocytic lymphohistiocytosis consisted of corticosteroids and/or intravenous immunoglobulins along with adapted antimicrobial therapy. Patients with hemophagocytic lymphohistiocytosis had a median overall survival of 14.9 months, which was significantly shorter than that of patients without hemophagocytic lymphohistiocytosis (22.1 months) (P=0.0016). Hemophagocytic lymphohistiocytosis was significantly associated with a higher rate of induction failure, mainly due to deaths in aplasia. Hemophagocytic lymphohistiocytosis can be diagnosed in up to 10% of patients with acute myeloid leukemia undergoing intensive chemotherapy and is associated with early mortality. Fever, very high ferritin levels and marrow hemophagocytosis represent the cornerstone of the diagnosis. Further biological studies are needed to better characterize and recognize this syndrome in patients with acute myeloid leukemia. 10.3324/haematol.2013.097394
    Novel Patient with Late-Onset Familial Hemophagocytic Lymphohistiocytosis with STXBP2 Mutations Presenting with Autoimmune Hepatitis, Neurological Manifestations and Infections Associated with Hypogammaglobulinemia. Esmaeilzadeh Hossein,Bemanian Mohammad Hasan,Nabavi Mohammad,Arshi Saba,Fallahpour Morteza,Fuchs Ilka,zur Stadt Udo,Warnatz Klaus,Ammann Sandra,Ehl Stephan,Lehmberg Kai,Rezaei Nima Journal of clinical immunology Familial hemophagocytic lymphohistiocytosis (FHL) is a genetically heterogeneous hyperinflammatory syndrome, caused by an uncontrolled and ineffective proliferation and activation of T-lymphocytes, NK-cells, and macrophages that infiltrate multiple organs. Herein, a patient is presented who suffered from hepatitis and atypical brain lesions. Genetic studies revealed a homozygous mutation in the STXP2 gene; and thus, the diagnosis of FHL5 was confirmed. 10.1007/s10875-014-0119-z
    Recommendations for the management of hemophagocytic lymphohistiocytosis in adults. La Rosée Paul,Horne AnnaCarin,Hines Melissa,von Bahr Greenwood Tatiana,Machowicz Rafal,Berliner Nancy,Birndt Sebastian,Gil-Herrera Juana,Girschikofsky Michael,Jordan Michael B,Kumar Ashish,van Laar Jan A M,Lachmann Gunnar,Nichols Kim E,Ramanan Athimalaipet V,Wang Yini,Wang Zhao,Janka Gritta,Henter Jan-Inge Blood Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome induced by aberrantly activated macrophages and cytotoxic T cells. The primary (genetic) form, caused by mutations affecting lymphocyte cytotoxicity and immune regulation, is most common in children, whereas the secondary (acquired) form is most frequent in adults. Secondary HLH is commonly triggered by infections or malignancies but may also be induced by autoinflammatory/autoimmune disorders, in which case it is called macrophage activation syndrome (MAS; or MAS-HLH). Most information on the diagnosis and treatment of HLH comes from the pediatric literature. Although helpful in some adult cases, this raises several challenges. For example, the HLH-2004 diagnostic criteria developed for children are commonly applied but are not validated for adults. Another challenge in HLH diagnosis is that patients may present with a phenotype indistinguishable from sepsis or multiple organ dysfunction syndrome. Treatment algorithms targeting hyperinflammation are frequently based on pediatric protocols, such as HLH-94 and HLH-2004, which may result in overtreatment and unnecessary toxicity in adults. Therefore, dose reductions, individualized tailoring of treatment duration, and an age-dependent modified diagnostic approach are to be considered. Here, we present expert opinions derived from an interdisciplinary working group on adult HLH, sponsored by the Histiocyte Society, to facilitate knowledge transfer between physicians caring for pediatric and adult patients with HLH, with the aim to improve the outcome for adult patients affected by HLH. 10.1182/blood.2018894618
    Genetic Deficiency of Interferon-γ Reveals Interferon-γ-Independent Manifestations of Murine Hemophagocytic Lymphohistiocytosis. Burn Thomas N,Weaver Lehn,Rood Julia E,Chu Niansheng,Bodansky Aaron,Kreiger Portia A,Behrens Edward M Arthritis & rheumatology (Hoboken, N.J.) OBJECTIVE:Familial hemophagocytic lymphohistiocytosis (FHLH) is a complex cytokine storm syndrome caused by genetic abnormalities rendering CD8+ T cells and natural killer cells incapable of cytolytic killing. In murine models of FHLH, interferon-γ (IFNγ) produced by CD8+ T cells has been identified as a critical mediator of disease, and an IFNγ-blocking antibody (emapalumab) has recently been approved by the Food and Drug Administration. However, development of hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) in patients who are genetically unresponsive to IFNγ questions the absolute necessity of IFNγ in driving disease. This study was undertaken to determine the necessity of IFNγ in driving HLH. METHODS:IFNγ Prf1 mice were infected with lymphocytic choriomeningitis virus (LCMV), and HLH immunopathologic features, including survival, weight loss, cytopenias, cytokine profiles, and immune cell phenotypes, were assessed. Mixed bone marrow chimeras were created to determine the immune cell-intrinsic role of IFNγ receptor signaling. CD8+ T cell depletion and interleukin-33 (IL-33)/ST2 blockade were performed using monoclonal antibodies. RESULTS:LCMV infection of IFNγ Prf1 mice resulted in severe HLH-like disease. CD8+ T cells and the IL-33/ST2 axis remained essential mediators of disease; however, IFNγ-independent HLH immunopathology correlated with a 10-15-fold increase in neutrophilia (P < 0.001) and an altered cytokine milieu dominated by IL-6, IL-1β, and granulocyte-macrophage colony-stimulating factor (GM-CSF) (P < 0.05). Furthermore, IFNγ regulated CD8+ T cell expression of GM-CSF and neutrophil survival. CONCLUSION:IFNγ is not necessary for the development of fulminant HLH, requiring physicians to consider case-by-case treatment strategies. Use of therapies that target upstream activators of CD8+ T cells, such as IL-33/ST2 signaling, may be more universally applicable treatment options that ameliorate both IFNγ-dependent and -independent manifestations of HLH/MAS. 10.1002/art.41076
    Therapeutic effect of JAK1/2 blockade on the manifestations of hemophagocytic lymphohistiocytosis in mice. Maschalidi Sophia,Sepulveda Fernando E,Garrigue Alexandrine,Fischer Alain,de Saint Basile Geneviève Blood Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome, characterized by severe hyperinflammation and immunopathological manifestations in several tissues. These features result from organ infiltration by overactivated CD8 T-cells and macrophages, which produce high levels of pro-inflammatory cytokines, such as IFN-γ, TNF-α, IL-6, and IL-18. Recently, several Janus kinase 1/2 (JAK1/2) inhibitors, such as ruxolitinib, have been developed as immunosuppressive agents. They have proven beneficial effects in the treatment of myeloproliferative disorders and inflammatory conditions. To determine whether pharmacological inhibition of the JAK1/2 not only prevents the onset of HLH immunopathology but also is effective against existing HLH, cytotoxicity-impaired Prf1(-/-) and Rab27a(-/-) mice with full-blown HLH syndrome were treated with a clinically relevant dose of ruxolitinib. In vivo, ruxolitinib treatment suppressed signal transducer and activator of transcription 1 activation and led to recovery from HLH manifestations in both murine models. In the Prf1(-/-) mice, these beneficial effects were evidenced by a greater survival rate, and in both murine models, they were evidenced by the correction of blood cytopenia and a rapid decrease in serum IL-6 and TNF-α levels. During ruxolitinib treatment, liver tissue damage receded concomitantly with a decrease in the number of infiltrating inflammatory macrophages and an increase in the number of alternatively activated macrophages. In Rab27a(-/-) mice, central nervous system involvement was significantly reduced by ruxolitinib therapy. Our findings demonstrate that clinically relevant doses of the JAK1/2 inhibitor ruxolitinib suppresses the harmful consequences of macrophage overactivation characterizing HLH in 2 murine models. The results could be readily translated into the clinic for the treatment of primary, and perhaps even secondary, forms of HLH. 10.1182/blood-2016-02-700013
    Hemophagocytic Lymphohistiocytosis Gene Variants in Childhood-Onset Systemic Lupus Erythematosus With Macrophage Activation Syndrome. The Journal of rheumatology OBJECTIVE:Macrophage activation syndrome (MAS), a life-threatening complication of systemic lupus erythematosus (SLE), resembles familial hemophagocytic lymphohistiocytosis (HLH), an inherited disorder of hyperinflammation. We compared the proportion of patients with childhood-onset SLE (cSLE) with and without MAS who carried low-frequency HLH nonsynonymous variants. METHODS:We enrolled patients from the Lupus Clinic at SickKids, Toronto. Demographic and clinical features were extracted from the SLE database and ancestry was genetically inferred using multiethnic genotyping array data. Patients with MAS (based on expert diagnosis) underwent either paired-end whole-exome sequencing (WES; read depth: 70-118X) or whole-genome sequencing (WGS). Patients without MAS had WGS (read depth: 37-40X). In 16 HLH genes, we prioritized low-frequency (minor allele frequency [MAF] < 0.05) exonic nonsynonymous variants. We compared the proportion of patients with and without MAS carrying HLH variants (Fisher exact test, < 0.05). MAFs were compared to an ancestrally matched general population (Trans-Omics for Precision Medicine [TOPMed] and Genome Aggregation Database [gnomAD]). RESULTS:The study included 81 patients with cSLE, 19 of whom had MAS. We identified 47 unique low-frequency nonsynonymous HLH variants. There was no difference in the proportion of patients with and without MAS carrying ≥ 1 HLH variants (37% vs 47%, = 0.44). The MAS cohort did not carry more HLH variants when compared to an ancestrally matched general population. CONCLUSION:In a single-center multiethnic cSLE cohort, we found no difference in the proportion of patients with MAS carrying nonsynonymous HLH genetic variants compared to patients without MAS. To our knowledge, this is the first study to examine the frequency of HLH genetic variants in relation to MAS among patients with cSLE. Future studies are required to validate our findings. 10.3899/jrheum.211200
    Hemophagocytic lymphohistiocytosis with immunotherapy: brief review and case report. Sadaat Masood,Jang Sekwon Journal for immunotherapy of cancer BACKGROUND:Hemophagocytic Lymphohistiocytosis (HLH), a rare but potentially fatal syndrome of immune hyperactivation, may be an under-recognized immune-related adverse event (irAE). Unlike other irAEs, HLH triggered by immune checkpoint blockade is not well described; no particular diagnostic guidelines and treatment regimens exist. The HLH-2004 criteria remain as the common diagnostic guide. For the treatment of HLH, various combinations of chemotherapeutic, immunosuppressive and glucocorticoid agents are used. CASE PRESENTATION:We report a case of HLH in a 58-year-old metastatic melanoma patient who was undergoing immune checkpoint blockade with pembrolizumab, a programmed cell death-1 (PD-1) receptor inhibitor. The patient presented with fever, upper normal sized spleen, anemia, thrombocytopenia, hypertriglyceridemia, hyperferritinemia, reduced NK cell activity and elevated sCD163 levels, fulfilling the Histiocyte Society HLH-2004 diagnostic criteria. Our patient was successfully treated with oral prednisone (1 mg/kilogram/day), suggesting that HLH from immune checkpoint inhibitors may respond to steroids alone. CONCLUSION:Early diagnosis and treatment of HLH are critical to avoid progressive tissue damage, organ failure and possibly death. HLH should be suspected in clinical presentations with fever, cytopenias and hyperinflammatory markers. HLH in the setting of immune checkpoint blockade may be treated with steroids only but further evidence is required. 10.1186/s40425-018-0365-3
    HIF1A is a critical downstream mediator for hemophagocytic lymphohistiocytosis. Huang Rui,Hayashi Yoshihiro,Yan Xiaomei,Bu Jiachen,Wang Jieyu,Zhang Yue,Zhou Yile,Tang Yuting,Wu Lingyun,Xu Zefeng,Liu Xin,Wang Qianfei,Zhou Jianfeng,Xiao Zhijian,Bridges James P,Marsh Rebecca A,Zhang Kejian,Jordan Michael B,Li Yuhua,Huang Gang Haematologica Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome characterized by overwhelming immune activation. A steroid and chemotherapy-based regimen remains as the first-line of therapy but it has substantial morbidity. Thus, novel, less toxic therapy for HLH is urgently needed. Although differences exist between familial HLH (FHL) and secondary HLH (sHLH), they have many common features. Using bioinformatic analysis with FHL and systemic juvenile idiopathic arthritis, which is associated with sHLH, we identified a common hypoxia-inducible factor 1A (HIF1A) signature. Furthermore, HIF1A protein levels were found to be elevated in the lymphocytic choriomeningitis virus infected mouse FHL model and the CpG oligodeoxynucleotide-treated mouse sHLH model. To determine the role of HIF1A in HLH, a transgenic mouse with an inducible expression of HIF1A/ARNT proteins in hematopoietic cells was generated, which caused lethal HLH-like phenotypes: severe anemia, thrombocytopenia, splenomegaly, and multi-organ failure upon HIF1A induction. Mechanistically, these mice show type 1 polarized macrophages and dysregulated natural killler cells. The HLH-like phenotypes in this mouse model are independent of both adaptive immunity and interferon-γ, suggesting that HIF1A is downstream of immune activation in HLH. In conclusion, our data reveal that HIF1A signaling is a critical mediator for HLH and could be a novel therapeutic target for this syndrome. 10.3324/haematol.2017.174979
    Central Nervous System Involvement of Hemophagocytic Lymphohistiocytosis: When 18F-FDG PET/CT Solves a Complex Diagnostic Investigation. Allard Bastien,Delcroix Olivier,Le Lez-Soquet Servane,Sacaze Elise,Querellou Solène Clinical nuclear medicine ABSTRACT:Hemophagocytic lymphohistiocytosis is rare life-threatening syndrome, hereditary or acquired, mainly affecting children. Hemophagocytic lymphohistiocytosis is an immune deficiency characterized by severe inflammation caused by uncontrolled proliferation of activated lymphocytes and macrophages. The usual biological and clinical data may associate polyadenopathy, hepatosplenomegaly, fever, multivisceral damages, and cytopenias with potential multiorgan dysfunction and death. We report the case of a 4-year-old girl, hospitalized for recurrent cerebellar symptoms (ataxia) associated later with fever and pancytopenia. 18F-FDG PET/CT revealed a node pathological uptake, which was biopsied and confirmed a diagnosis of hemophagocytic lymphohistiocytosis. 10.1097/RLU.0000000000003663
    Nivolumab treatment of relapsed/refractory Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis in adults. Liu Pengpeng,Pan Xiangyu,Chen Chong,Niu Ting,Shuai Xiao,Wang Jian,Chen Xuelan,Liu Jiazhuo,Guo Yong,Xie Liping,Wu Yu,Liu Yu,Liu Ting Blood Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (EBV-HLH) is a life-threatening hyperinflammatory syndrome triggered by EBV infection. It often becomes relapsed or refractory (r/r), given that etoposide-based regimens cannot effectively clear the virus. r/r EBV-HLH is invariably lethal in adults without allogeneic hematopoietic stem cell transplantation. Here, we performed a retrospective analysis of 7 r/r EBV-HLH patients who were treated with nivolumab on a compassionate-use basis at West China Hospital. All 7 patients tolerated the treatment and 6 responded to it. Five of them achieved and remained in clinical complete remission with a median follow-up of 16 months (range, 11.4-18.9 months). Importantly, both plasma and cellular EBV-DNAs were completely eradicated in 4 patients. Single-cell RNA-sequencing analysis showed that HLH syndrome was associated with hyperactive monocytes/macrophages and ineffective CD8 T cells with a defective activation program. Nivolumab treatment expanded programmed death protein-1-positive T cells and restored the expression of HLH-associated degranulation and costimulatory genes in CD8 T cells. Our data suggest that nivolumab, as a monotherapy, provides a potential cure for r/r EBV-HLH, most likely by restoring a defective anti-EBV response. 10.1182/blood.2019003886
    Pediatric hemophagocytic lymphohistiocytosis. Canna Scott W,Marsh Rebecca A Blood Hemophagocytic lymphohistiocytosis (HLH) is a syndrome describing patients with severe systemic hyperinflammation. Characteristic features include unremitting fever, cytopenias, hepatosplenomegaly, and elevation of typical HLH biomarkers. Patients can develop hepatitis, coagulopathy, liver failure, central nervous system involvement, multiorgan failure, and other manifestations. The syndrome has a high mortality rate. More and more, it is recognized that while HLH can be appropriately used as a broad summary diagnosis, many pediatric patients actually suffer from an expanding spectrum of genetic diseases that can be complicated by the syndrome of HLH. Classic genetic diseases in which HLH is a typical and common manifestation include pathogenic changes in familial HLH genes (PRF1, UNC13D, STXBP2, and STX11), several granule/pigment abnormality genes (RAB27A, LYST, and AP3B1), X-linked lymphoproliferative disease genes (SH2D1A and XIAP), and others such as NLRC4, CDC42, and the Epstein-Barr virus susceptibility diseases. There are many other genetic diseases in which HLH is an infrequent complication of the disorder as opposed to a prominent manifestation of the disease caused directly by the genetic defect, including other primary immune deficiencies and inborn errors of metabolism. HLH can also occur in patients with underlying rheumatologic or autoinflammatory disorders and is usually designated macrophage activation syndrome in those settings. Additionally, HLH can develop in patients during infections or malignancies without a known (or as-yet-identified) genetic predisposition. This article will attempt to summarize current concepts in the pediatric HLH field as well as offer a practical diagnostic and treatment overview. 10.1182/blood.2019000936
    Hemophagocytic Lymphohistiocytosis. Al-Samkari Hanny,Berliner Nancy Annual review of pathology Hemophagocytic lymphohistiocytosis is a life-threatening disorder characterized by unbridled activation of cytotoxic T lymphocytes, natural killer (NK) cells, and macrophages resulting in hypercytokinemia and immune-mediated injury of multiple organ systems. It is seen in both children and adults and is recognized as primary (driven by underlying genetic mutations that abolish critical proteins required for normal function of cytotoxic T cells and NK cells) or secondary (resulting from a malignant, infectious, or autoimmune stimulus without an identifiable underlying genetic trigger). Clinical and laboratory manifestations include fever, splenomegaly, neurologic dysfunction, coagulopathy, liver dysfunction, cytopenias, hypertriglyceridemia, hyperferritinemia, hemophagocytosis, and diminished NK cell activity. It is treated with immune suppressants, etoposide, and allogeneic hematopoietic stem cell transplantation; more than 50% of children who undergo transplant survive, but adults have quite poor outcomes even with aggressive management. Newer agents directed at subduing the uncontrolled immune response in a targeted fashion offer promise in this highly morbid disease. 10.1146/annurev-pathol-020117-043625
    A Personalized Diagnostic and Treatment Approach for Macrophage Activation Syndrome and Secondary Hemophagocytic Lymphohistiocytosis in Adults. Kumar Bharat,Aleem Sohaib,Saleh Hana,Petts Jennifer,Ballas Zuhair K Journal of clinical immunology OBJECTIVE:We assessed the clinical features and outcomes based on therapeutic options adopted during hospital stay for adult patients with macrophage activation syndrome and secondary hemophagocytic lymphohistiocytosis (MAS/sHLH). METHODS:We conducted a retrospective chart review of all adult patients (age ≥ 18 years) diagnosed with MAS/sHLH at our center between 2010 and 2015. Inclusion criteria for patients were diagnosis of MAS/sHLH during admission and patients meeting at least 5 out of 8 of Henter's criteria or at least 4 out of 6 of the criteria that were tested. RESULTS:Nineteen adult patients with MAS/sHLH met the inclusion criteria from January 2010 to October 2015 (median age 48 years; female 68.4%). Treatment had been personalized, depending on the clinical presentation and course of disease. Majority of the patients received anakinra, cyclosporine, intravenous immunoglobulins (IVIG), and steroids. Fourteen (74%) patients survived, with clinical improvement by the time of discharge. After excluding the three patients with underlying leukemia/lymphoma who opted for palliative care and subsequently died, the survival rate was 88%. CONCLUSION:A modified diagnostic and treatment protocol for adult patients with MAS/sHLH that incorporated graded introduction of medications based on clinical presentation and cytokine profile resulted in the best adult survival rate reported in literature. 10.1007/s10875-017-0439-x
    Development and Initial Validation of the Macrophage Activation Syndrome/Primary Hemophagocytic Lymphohistiocytosis Score, a Diagnostic Tool that Differentiates Primary Hemophagocytic Lymphohistiocytosis from Macrophage Activation Syndrome. Minoia Francesca,Bovis Francesca,Davì Sergio,Insalaco Antonella,Lehmberg Kai,Shenoi Susan,Weitzman Sheila,Espada Graciela,Gao Yi-Jin,Anton Jordi,Kitoh Toshiyuki,Kasapcopur Ozgur,Sanner Helga,Merino Rosa,Astigarraga Itziar,Alessio Maria,Jeng Michael,Chasnyk Vyacheslav,Nichols Kim E,Huasong Zeng,Li Caifeng,Micalizzi Concetta,Ruperto Nicolino,Martini Alberto,Cron Randy Q,Ravelli Angelo,Horne AnnaCarin, The Journal of pediatrics OBJECTIVE:To develop and validate a diagnostic score that assists in discriminating primary hemophagocytic lymphohistiocytosis (pHLH) from macrophage activation syndrome (MAS) related to systemic juvenile idiopathic arthritis. STUDY DESIGN:The clinical, laboratory, and histopathologic features of 362 patients with MAS and 258 patients with pHLH were collected in a multinational collaborative study. Eighty percent of the population was assessed to develop the score and the remaining 20% constituted the validation sample. Variables that entered the best fitted model of logistic regression were assigned a score, based on their statistical weight. The MAS/HLH (MH) score was made up with the individual scores of selected variables. The cutoff in the MH score that discriminated pHLH from MAS best was calculated by means of receiver operating characteristic curve analysis. Score performance was examined in both developmental and validation samples. RESULTS:Six variables composed the MH score: age at onset, neutrophil count, fibrinogen, splenomegaly, platelet count, and hemoglobin. The MH score ranged from 0 to 123, and its median value was 97 (1st-3rd quartile 75-123) and 12 (1st-3rd quartile 11-34) in pHLH and MAS, respectively. The probability of a diagnosis of pHLH ranged from <1% for a score of <11 to >99% for a score of  ≥123. A cutoff value of ≥60 revealed the best performance in discriminating pHLH from MAS. CONCLUSION:The MH score is a powerful tool that may aid practitioners to identify patients who are more likely to have pHLH and, thus, could be prioritized for functional and genetic testing. 10.1016/j.jpeds.2017.06.005
    Monocytes From Patients With Macrophage Activation Syndrome and Secondary Hemophagocytic Lymphohistiocytosis Are Hyperresponsive to Interferon Gamma. Pascarella Antonia,Bracaglia Claudia,Caiello Ivan,Arduini Alessia,Moneta Gian Marco,Rossi Marianna Nicoletta,Matteo Valentina,Pardeo Manuela,De Benedetti Fabrizio,Prencipe Giusi Frontiers in immunology Objective:To investigate the activation of the IFNγ signaling pathway in monocytes of patients with secondary hemophagocytic lymphohistiocytosis (sHLH)/macrophage activation syndrome (MAS) and to evaluate whether levels of phosphorylated STAT1 represent a biomarker for the identification of patients at early stages of the disease. Methods:Fresh whole blood samples from pediatric patients with active sHLH/MAS, not receiving (n=10) and receiving glucocorticoids (n=14) at time of sampling, were prospectively collected. As disease control groups, patients with active systemic juvenile idiopathic arthritis (sJIA) without MAS, patients with sHLH/MAS in remission and patients with other rheumatic diseases were also sampled. Whole blood cells were left unstimulated or stimulated with increasing concentrations of IFNγ for 10 minutes and the intracellular Tyrosine (701)-phosphorylated STAT1 (pSTAT1) levels were evaluated in monocytes by flow cytometry. Results:Monocytes from untreated sHLH/MAS patients showed significantly higher basal levels of pSTAT1 compared to those observed in monocytes from glucocorticoid-treated sHLH/MAS patients and from all the other disease controls. In addition, a significant increase in responsiveness to IFNγ, as assessed by increased levels of pSTAT1 following stimulation, was observed in monocytes from untreated sHLH/MAS patients. pSTAT1 levels in monocytes distinguished patients with sHLH/MAS not treated with glucocorticoids from patients with active sJIA or with other rheumatic diseases [AUC, 0.93; 95% confidence interval 0.85-1.00, p<0.001]. Statistically significant correlations between mRNA levels in whole blood cells, circulating IFNγ levels and pSTAT1 levels in sHLH/MAS monocytes were found. Conclusion:Our data demonstrating higher basal levels of pSTAT1 as well as a hyperreactivity to IFNγ stimulation in monocytes from patients with sHLH/MAS point to perturbations in the activation of downstream IFNγ signaling pathway as a contributor to the hyperinflammation occurring in these patients. Finally, the observation that glucocorticoids affect pSTAT1 levels , makes it difficult to consider the measurement of pSTAT1 levels as a biomarker to identify patients at early stages of sHLH/MAS in clinical practice. 10.3389/fimmu.2021.663329
    Usefulness of Interleukin-18 as a Diagnostic Biomarker to Differentiate Adult-Onset Still's Disease With/Without Macrophage Activation Syndrome From Other Secondary Hemophagocytic Lymphohistiocytosis in Adults. Shiga Toshihiko,Nozaki Yuji,Tomita Daisuke,Kishimoto Kazuya,Hirooka Yasuaki,Kinoshita Koji,Funauchi Masanori,Matsumura Itaru Frontiers in immunology Background:Interleukin (IL)-18 is markedly elevated in systemic inflammatory diseases that cause the 'cytokine storm' such as adult-onset Still's disease (AOSD) and hemophagocytic lymphohistiocytosis (HLH). The differences in IL-18 between AOSD and HLH, especially in adults, is uncertain. Macrophage activation syndrome (MAS), a form of secondary HLH, is often difficult to differentiate cases of AOSD that include MAS from other secondary HLH. In this case-control study, we investigated whether serum IL-18 levels could be a useful biomarker for the differential diagnosis of AOSD with or without MAS (AOSD group) and other secondary HLH in adults (adult HLH group). Patients and Methods:We enrolled 46 patients diagnosed with AOSD including 9 patients with MAS and 31 patients in the adult HLH group, which excluded AOSD-associated MAS. The clinical features and laboratory data were compared between the AOSD and adult HLH groups. In addition, we subdivided the AOSD group (with or without MAS) and the adult HLH group (whether lymphoma-associated or not) and compared the four groups. A logistic regression analysis was used to identify factors with high efficacy in differentiating the two groups, followed by a receiver operating characteristic (ROC) curve analysis to evaluate the differential diagnostic ability of IL-18. We analyzed the correlation between IL-18 and various laboratory parameters in the AOSD group. Results:Serum IL-18 levels of patients in the AOSD groups were significantly higher than those of the adult HLH groups, and were closely correlated with ferritin, soluble interleukin-2 receptor (sIL-2R), and other laboratory data. Univariate and multivariate logistic regression analyses revealed that IL-18, sIL-2R, and 'arthralgia or arthritis' are independent factors useful in the differential diagnosis of AOSD from adult HLH. In the differential diagnosis of both groups, the area under the curve obtained from the ROC curve of IL-18 with a cutoff value of 18,550 pg/mL was 0.91 (95% confidence interval 0.83-1.00; sensitivity 90.3%, specificity 93.5%), and the differential diagnosis ability of IL-18 was superior to that of other laboratory data. Conclusions:IL-18 could be a useful biomarker for the differential diagnosis of AOSD and adult HLH. 10.3389/fimmu.2021.750114