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RESEARCH PRODUCT

P.21.2 New insights into eosinophilic fasciitis

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Eosinophilic fasciitis (EF), first described by Shulman in 1974, is a rare disease characterized by fibrosis and inflammatory infiltration of the muscle fascia as well as scleroderma-like skin indurations and blood eosinophilia. In contrast to other inflammatory myopathies, patients generally show less muscle weakness and myalgia, and a frequent increase in body weight. Thus, we hypothesize a unique immune mechanism underlying Shulman syndrome. The immunohistochemical expression pattern of leucocytes and a comprehensive panel of cytokine and chemokine expression on RNA level of muscle specimen from EF patients were compared to healthy control muscle. In patients with biopsy-proven EF the immune phenotype of inflammatory cells was determined and RNA from fascia and adjacent muscle was isolated to assess activators of the T helper cell 1 (Th1) – classical macrophage activation (M1) and Th2–M2 immune response by real-time PCR. The inflammatory infiltrate located at the muscle-fascia interface is mainly composed of CD206+ M2 macrophages with focal accumulations of CD4+ and CD8+ T cells while B cells and plasma cells are rare. Eosinophils could be detected in all of the EF cases. MHC class I is upregulated diffusely while MHC class II expression is pronounced in the perifascicular region accompanied by a perifascicular atrophy of muscle fibers, comparable to Dermatomyositis. Activators of the Th2–M2 pathway like STAT6 and IL-4 are upregulated leading to higher expression levels of CD206. Activators of the Th1–M1 pathway like STAT1 and interferon-a are also upregulated, however, they do not translate into a significant upregulation of M1 markers. We could show a specific immune phenotype of leucocyte infiltrates in Shulman syndrome with a mixed Th1/Th2 phenotype that resulted in a dominant M2 immune response.