In this study, we aimed to determine retinoic acid-inducible gene I (RIG-I) expression in peripheral T lymphocytes and explore the correlation between RIG-I and T cell lymphopenia in DM.
Sarcoplasmic MxA expression is more sensitive than PFA and RIG-I expression for a pathological diagnosis of DM, regardless of the autoantibody-related subgroup.
We studied by immunohistochemical analysis the expression of RIG-I and the presence of perifascicular atrophy in 115 coded muscle biopsies: 44 patients with DM, 18 with myositis with overlap, 8 with ASS, 27 with non-DM inflammatory myopathy (16 with polymyositis, 6 with inclusion body myositis, 5 with immune-mediated necrotizing myopathy), 8 with muscular dystrophy (4 with dysferlinopathy, 4 with fascioscapulohumeral muscle dystrophy) and 10 healthy controls.
RIG-I-mediated innate immunity, triggered by a viral or damage signal, plays a significant role in the pathogenesis of DM, but not in that of PM or IBM.