Update on immunopathogenesis in inflammatory myopathies.

Previous studies on myositis have suggested that these disorders are autoimmune in nature, and have provided evidence that myositis-specific autoantibodies and autoreactive T cells are present in affected patients. Recent studies provide evidence for the upregulation of various immunologically relevant cell surface molecules, cytokines, and chemokines, suggesting active cell-cell interactions. Understanding these interactions may provide novel therapeutic targets in these diseases. The role of skeletal muscle cells and their contribution to the immune response has become more important as a result of the advent of therapeutic strategies such as myoblast implantation, DNA vaccination, and gene therapy for various disease conditions. Understanding the immunologic capabilities of skeletal muscle cells may provide important clues not only to the mechanisms of the autoimmune response, but also to the use of skeletal muscle as the site of transgene expression to correct genetic defects.