New insights into immune mechanisms underlying response to Rituximab in patients with membranous nephropathy: A prospective study and a review of the literature. Roccatello D,Sciascia S,Di Simone D,Solfietti L,Naretto C,Fenoglio R,Baldovino S,Menegatti E Autoimmunity reviews BACKGROUND:Idiopathic membranous nephropathy (MN) is a common immune-mediated glomerular disease and the main cause of nephrotic syndrome (NS) in Caucasian adults. Rituximab (RTX) has been reported to safely reduce proteinuria in patients with primary MN and severe NS. However, the effects of RTX treatment on T-cells including regulatory T-cells (Treg) in MN have not been fully determined. METHODS:Seventeen patients [mean age 67 (29-86) years, 6 women, 11 men] with biopsy-proven MN, and persistent proteinuria >3.5 g/24h were prospectively enrolled and received RTX, 375 mg/m(2) (iv) on days 1, 8, 15 and 22. Changes in circulating B and T cell homeostasis were examined in the peripheral blood by flow-cytometry studies; serum levels of IL-35 were measured using a high-sensitivity ELISA kits (baseline, at month 3, 6, 9 and 12). RESULTS:Patients had been followed-up for a mean of 36.3 months (24-48). Proteinuria decreased from 5.6 (3.5-8) g/24h to 2.4 (0.06-13) g/24h at 6 months (p<0.05) and to 1.3 (0.06-8) at 12 months (p<0.01), respectively after therapy with RTX. Four patients received a 2nd course of RTX (one at 6 months because of persistent NS, and three at 12, 18, or 30 months for relapse). The three relapsing patients became proteinuria-free (<0.5 g/24h) in the following 6 months. Serum creatinine remained stable during the follow-up: median 1mg/dl (0.7-1.6) at 12 months and 1.1 (0.7-1.7) at 24 months as compared to 1 (0.5-2.4) at baseline. At 6 months after RTX, complete remission (CR) was observed in 7 patients, partial remission (PR) in 4, while 6 were non responders (NR) non responder (NR). At the end of the follow-up, 14 patients were in CR, 1 in PR, while 2 were NR. In the T-cell compartment, upon detection of B cell depletion, there was an increase in Treg up to 10-fold when comparing baseline and at month 12 (mean ± SD 1.2 ± 0.6%, and 5.8 ± 0.7% p=0.02, respectively). When stratifying patients in responders (CR+PR) and NRs at month 12, we observed a significant increase in Treg cells from month 6 which persisted till 12 months only in the responder group (5.5 ± 0.6% and 1.1 ± 0.6%, p=0.04, respectively in responders and NRs). A statistically significant decrease in the levels of active T-lymphocytes (HLA-DR+CD8+ cells) was observed, with a maximum reached at 12 months after treatment with RTX [6 ± 1.1% baseline, 4.7 ± 1.7% at 6 months (p=0.043) and 1.5 ± 1.4% at 12 months (p=0.05)]. A marked increase in IL-35 levels [defined as delta >40% (serum values at 6 months minus baseline values)] was seen in 68% of the patients who achieved clinical response (CR or PR) at 12 month, but in none of the patients who failed to respond (p=0.034). CONCLUSION:Our findings and data from literature support the idea that RTX can be envisaged as a first-line therapy for patients at risk of progression because of persistent NS due to idiopathic MN. Insights into the putative T cell-related mechanisms of action have been discussed. 10.1016/j.autrev.2016.02.014

Depletion of functionally active CD20+ T cells by rituximab treatment. Wilk Esther,Witte Torsten,Marquardt Nicole,Horvath Tibor,Kalippke Katy,Scholz Kirsten,Wilke Nadine,Schmidt Reinhold E,Jacobs Roland Arthritis and rheumatism OBJECTIVE:Rituximab is a therapeutic anti-CD20 antibody used for in vivo depletion of B cells in proliferative and autoimmune diseases. However, the mechanisms of action are not fully understood, since not all of the therapy-mediated effects can be explained by the depletion of antibody-secreting cells. In addition to B cells, there is also a small population of T cells coexpressing CD20 in all individuals. This study was conducted to examine the phenotype and function of CD3+CD20+ T cells in patients with rheumatoid arthritis (RA) and healthy controls. METHODS:The phenotype and apoptosis of peripheral blood mononuclear cells from healthy donors and RA patients were examined by 4-color fluorescence-activated cell sorting analyses. Cytokine production was determined by intracellular staining and measurement of cytokines in the supernatants. Proliferation of sorted T cell populations was analyzed using 3H-thymidine uptake assays. RESULTS:In healthy individuals, 0.1-6.8% of peripheral blood T cells (mean 1.6%; n=142) coexpressed CD20, which was not significantly different from that in the peripheral blood of RA patients, in whom 0.4-2.6% of T cells (mean 1.2%; n=27) were CD20+. During rituximab therapy, the CD20+ T cells along with the B cells were eliminated from the RA peripheral blood. Among the CD20+ T cells, 45% coexpressed CD8 and 55% coexpressed CD4. Polyclonal CD3+CD20+ cells were functionally characterized by constitutive cytokine production (i.e., interleukin-1beta and tumor necrosis factor alpha), a low proliferative capacity, a high activation state, and enhanced susceptibility to apoptosis. CONCLUSION:These findings suggest that CD20+ T cells represent a terminally differentiated cell type with immune-regulatory and proinflammatory capacities. Depletion of CD20+ T cells may be an additional mechanism by which anti-CD20 therapy functions in patients with RA. 10.1002/art.24998

Rituximab-induced B cell depletion in autoimmune diseases: potential effects on T cells. Liossis Stamatis-Nick C,Sfikakis Petros P Clinical immunology (Orlando, Fla.) Peripheral B cell depletion strategies have been employed recently in the treatment of systemic autoimmune diseases and the initial clinical results have been encouraging. Although the major target of rituximab-based treatments was to reduce the levels of circulating autoantibodies, additional mechanisms of action may operate. Recent studies have addressed the question of potential effects of transient B cell depletion on other, non-B cell populations. The data, albeit uncontrolled, suggest that anti-CD20 monoclonal antibody treatment is associated with significant effects in the T cell pool, whereas individual clinical responses do not always correlate with changes in autoantibody titers. More specifically, it has been reported that rituximab administration may decrease the activated phenotype of peripheral and tissue-resident T cells by abolishing antigen presentation by B cells, and may enhance the numbers and function of regulatory T cells. In this review we analyze and discuss available data emerging from B cell depletion studies in patients with systemic lupus erythematosus, rheumatoid arthritis and other autoimmune conditions. Further controlled studies are needed to confirm the role of B cell depletion in modifying T cell function in vivo. 10.1016/j.clim.2008.01.011

Anti-CD20 monoclonal antibodies: beyond B-cells. Avivi Irit,Stroopinsky Dina,Katz Tamar Blood reviews Anti-CD20 monoclonal antibodies (MoAbs), employed in treating CD20⁺ lymphomas and autoimmune diseases, appear to have broader functions than just eradicating malignant B-cells and decreasing autoantibody production. Rituximab-induced T-cell inactivation, reported both in-vitro and in-vivo, may contribute to the increased risk of T-cell-dependent infections, observed in patients receiving this therapy. T-cell polarization into a suppressive phenotype, often observed in patients receiving rituximab for autoimmune disorders, was reported to be associated with prolonged remissions. Elimination of B-cells serving as antigen-presenting cells, thereby causing impaired T-cell activation, could play a significant role in induction of these changes. Direct binding of rituximab to a CD20dim T-cell population, inducing its depletion, may contribute to the decreased T-cell activation following rituximab therapy. Further investigation of the complex network through which rituximab and new anti-CD20 MoAbs act, would advance the employment of these agents in different clinical settings. 10.1016/j.blre.2013.07.002

B- and T-cell subpopulations in patients with severe idiopathic membranous nephropathy may predict an early response to rituximab. Rosenzwajg Michelle,Languille Eva,Debiec Hanna,Hygino Joana,Dahan Karine,Simon Tabassome,Klatzmann David,Ronco Pierre Kidney international Primary membranous nephropathy (PMN) is characterized by antibodies to the podocyte, but little is known about B- and T-cell populations and their response to rituximab is controversial. To help resolve this we compared 33 lymphocyte subpopulations and 27 cytokines/chemokines in 25 patients with severe PMN and 27 age-matched healthy individuals. At baseline, patients had a significantly increased percentage of naive B-cells with significantly decreased switched and non-switched memory B-cells. There was a significantly decreased percentage of natural killer (NK) cells with an increase in the CD56CD16 NK subset. There were a significantly decreased percentage of regulatory T cells, together with an increased plasma concentration of TNF-alpha, IL-5 and IL-2RA. We then investigated 16 patients at eight days and three and six months after treatment with rituximab added to supportive therapy compared to nine patients with supportive therapy alone. After rituximab, B-cell recovery was still incomplete at six months, with persistent alterations of B-cell subsets, a significant increase of both T-regulatory (Treg) cells and NK cells, and a significant decrease of both the CD56CD16 NK subset and TNF-alpha levels. The patients who clinically responded to rituximab had a significantly lower percentage of Tregs at baseline compared to non-responders and a significantly increased percentage at day eight. Tregs remained unchanged in non-responders and in patients treated with supportive therapy alone. Thus, evaluation of Tregs might be useful for predicting early response to rituximab. 10.1016/j.kint.2017.01.012