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PD1 pathway in immune-mediated myopathies

2019; Wolters Kluwer; Volume: 6; Issue: 3 Linguagem: Inglês

10.1212/nxi.0000000000000558

2332-7812

Samuel Knauß, Corinna Preuße, Yves Allenbach, Sarah Léonard-Louis, Mehdi Touat, Norina Fischer, Helena Radbruch, Ronja Mothes, Vitali Matyash, Wolfgang Böhmerle, Matthias Endres, Hans‐Hilmar Goebel, Olivier Benveniste, Werner Stenzel,

Immunodeficiency and Autoimmune Disorders

Objective To investigate the relevance of dysfunctional T cells in immune-mediated myopathies. We analyzed T-cell exhaustion and senescence, in the context of programmed cell death protein 1 (PD1)-related immunity in skeletal muscle biopsies from patients with immune-mediated necrotizing myopathy (IMNM), sporadic inclusion body myositis (sIBM), and myositis induced by immune checkpoint inhibitors (irMyositis). Methods Skeletal muscle biopsies from 12 patients with IMNM, 7 patients with sIBM, and 8 patients with irMyositis were analyzed by immunostaining and immunofluorescence as well as by quantitative PCR. Eight biopsies from nondisease participants served as controls. Results CD3 + CD8 + T cells in biopsies from IMNM, sIBM, and irMyositis were largely PD1-positive, while CD68 + macrophages were sparsely positive to the ligand of programmed cell death protein 1 (PD-L1). The sarcolemma of myofibers was PD-L2 + and was colocalized with major histocompatibility complex (MHC) class I. CD68 + macrophages were colocalized with PD-L2. Senescent T cells were strongly enriched in skeletal muscle of sIBM, revealing a distinct immunologic signature. Biopsies from patients with irMyositis showed mild signs of senescence and exhaustion. Conclusion Persistent exposure to antigens in IMNMs and sIBM may lead to T-cell exhaustion, a process controlled by the PD1 receptor and its cognate ligands PD-L1/PD-L2. To our knowledge, these data are the first evidence of presence of dysfunctional T cells and relevance of the PD1 pathway in IMNM, sIBM, and irMyositis. These findings may guide the way to a novel understanding of the immune pathogenesis of immune-mediated myopathies.