Dysregulation of Antiviral Function of CD8(+) T Cells in the Chronic Obstructive Pulmonary Disease Lung. Role of the PD-1-PD-L1 Axis. American journal of respiratory and critical care medicine RATIONALE:Patients with chronic obstructive pulmonary disease (COPD) are susceptible to respiratory viral infections that cause exacerbations. The mechanisms underlying this susceptibility are not understood. Effectors of the adaptive immune response-CD8(+) T cells that clear viral infections-are present in increased numbers in the lungs of patients with COPD, but they fail to protect against infection and may contribute to the immunopathology of the disease. OBJECTIVES:CD8(+) function and signaling through the programmed cell death protein (PD)-1 exhaustion pathway were investigated as a potential key mechanism of viral exacerbation of the COPD lung. METHODS:Tissue from control subjects and patients with COPD undergoing lung resection was infected with live influenza virus ex vivo. Viral infection and expression of lung cell markers were analyzed using flow cytometry. MEASUREMENTS AND MAIN RESULTS:The proportion of lung CD8(+) T cells expressing PD-1 was greater in COPD (mean, 16.2%) than in controls (4.4%, P = 0.029). Only epithelial cells and macrophages were infected with influenza, and there was no difference in the proportion of infected cells between controls and COPD. Infection up-regulated T-cell PD-1 expression in control and COPD samples. Concurrently, influenza significantly up-regulated the marker of cytotoxic degranulation (CD107a) on CD8(+) T cells (P = 0.03) from control subjects but not on those from patients with COPD. Virus-induced expression of the ligand PD-L1 was decreased on COPD macrophages (P = 0.04) with a corresponding increase in IFN-γ release from infected COPD explants compared with controls (P = 0.04). CONCLUSIONS:This study has established a signal of cytotoxic immune dysfunction and aberrant immune regulation in the COPD lung that may explain both the susceptibility to viral infection and the excessive inflammation associated with exacerbations. 10.1164/rccm.201504-0782OC

Lung Dendritic Cells Drive Natural Killer Cytotoxicity in Chronic Obstructive Pulmonary Disease via IL-15Rα. American journal of respiratory and critical care medicine RATIONALE:Lung natural killer cells (NKs) kill a greater percentage of autologous lung parenchymal cells in chronic obstructive pulmonary disease (COPD) than in nonobstructed smokers. To become cytotoxic, NKs require priming, typically by dendritic cells (DCs), but whether priming occurs in the lungs in COPD is unknown. METHODS:We used lung tissue and in some cases peripheral blood from patients undergoing clinically indicated resections to determine in vitro killing of CD326 lung epithelial cells by isolated lung CD56 NKs. We also measured the cytotoxicity of unprimed blood NKs after preincubation with lung DCs. To investigate mechanisms of DC-mediated priming, we used murine models of COPD induced by cigarette smoke (CS) exposure or by polymeric immunoglobulin receptor (pIgR) deficiency, and blocked IL-15Rα (IL-15 receptor α subunit) trans-presentation by genetic and antibody approaches. RESULTS:Human lung NKs killed isolated autologous lung epithelial cells; cytotoxicity was increased (P = 0.0001) in COPD, relative to smokers without obstruction. Similarly, increased lung NK cytotoxicity compared with control subjects was observed in CS-exposed mice and pIgR mice. Blood NKs both from smokers without obstruction and subjects with COPD showed minimal epithelial cell killing, but in COPD, preincubation with lung DCs increased cytotoxicity. NKs were primed by CS-exposed murine DCs in vitro and in vivo. Inhibiting IL-15Rα trans-presentation eliminated NK priming both by murine CS-exposed DCs and by lung DCs from subjects with COPD. CONCLUSIONS:Heightened NK cytotoxicity against lung epithelial cells in COPD results primarily from lung DC-mediated priming via IL-15 trans-presentation on IL-15Rα. Future studies are required to test whether increased NK cytotoxicity contributes to COPD pathogenesis. 10.1164/rccm.201712-2513OC

Human Lung Conventional Dendritic Cells Orchestrate Lymphoid Neogenesis during Chronic Obstructive Pulmonary Disease. Naessens Thomas,Morias Yannick,Hamrud Eva,Gehrmann Ulf,Budida Ramachandramouli,Mattsson Johan,Baker Tina,Skogberg Gabriel,Israelsson Elisabeth,Thörn Kristofer,Schuijs Martijn J,Angermann Bastian,Melville Faye,Staples Karl J,Cunoosamy Danen M,Lambrecht Bart N American journal of respiratory and critical care medicine Emerging evidence supports a crucial role for tertiary lymphoid organs (TLOs) in chronic obstructive pulmonary disease (COPD) progression. However, mechanisms of immune cell activation leading to TLOs in COPD remain to be defined. To examine the role of lung dendritic cells (DCs) in T follicular helper (Tfh)-cell induction, a T-cell subset critically implicated in lymphoid organ formation, in COPD. Myeloid cell heterogeneity and phenotype were studied in an unbiased manner via single-cell RNA sequencing on HLA-DR cells sorted from human lungs. We measured the capability of control and COPD lung DC subsets, sorted using a fluorescence-activated cell sorter, to polarize IL-21CXCL13 (IL-21-positive and C-X-C chemokine ligand type 13-positive) Tfh-like cells. imaging analysis was performed on Global Initiative for Chronic Obstructive Lung Disease stage IV COPD lungs with TLOs. Single-cell RNA-sequencing analysis revealed a high degree of heterogeneity among human lung myeloid cells. Among these, conventional dendritic type 2 cells (cDC2s) showed increased induction of IL-21CXCL13 Tfh-like cells. Importantly, the capacity to induce IL-21 Tfh-like cells was higher in cDC2s from patients with COPD than in those from control patients. Increased Tfh-cell induction by COPD cDC2s correlated with increased presence of Tfh-like cells in COPD lungs as compared with those in control lungs, and cDC2s colocalized with Tfh-like cells in TLOs of COPD lungs. Mechanistically, cDC2s exhibited a unique migratory signature and (transcriptional) expression of several pathways and genes related to DC-induced Tfh-cell priming. Importantly, blocking the costimulatory OX40L (OX40 ligand)-OX40 axis reduced Tfh-cell induction by control lung cDC2s. In COPD lungs, we found lung EBI2 (Epstein-Barr virus-induced gene 2-positive) OX-40L-expressing cDC2s that induced IL-21 Tfh-like cells, suggesting an involvement of these cells in TLO formation. 10.1164/rccm.201906-1123OC