Different sites of B-lymphocyte activation in Anti-Jo-1 antibody associated myositis and in dermatomyositis

Objectives: In Dermatomyositis (DM) the humoral immune response is directed against perimysial and endomysial vascular elements and plays an important role in the pathogenesis. Although in anti-Jo-1 antibody associated myositis (anti-Jo-1 myositis) predominantly perimysial infiltration of T-cells and macrophages has been shown, the role of the humoral response has not yet been established. Methods: Plasma cells (PC) and B-cells (BC) were counted in perivascular, perimysial and endomysial regions in muscle biopsies of patients with anti-Jo-1 myositis (n=4), DM (n=6) and in diseased controls including PM (n=7), IB…