Accumulation of mature B cells in the inflamed muscle tissue of a patient with anti-155/140 antibody-positive juvenile dermatomyositis

摘要

We report the first case of a Japanese patient with anti-155/140 antibody-positive juvenile dermatomyositis (JDM). Her clinical features included severe cutaneous involvement. Serum B cell-activating factor levels were significantly increased. Mature class-switched memory B cells accumulated in inflamed muscle tissue but decreased in peripheral blood. These findings indicate that loss of B cell tolerance and accumulation of mature B cells in inflamed muscle tissue play an important role in the pathogenesis of JDM.