Cell-Mediated cytotoxicity to muscle in polymyositis
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Immunologic injury to cultures of skeletal muscle was studied in patients with polymyositis by means of a 51Cr release method that allows quantitation of myocyte injury. Lymphocyte-mediated myotoxicity was elevated in a group of nine patients with active disease (p<0.001) but was normal in four patients with inactive disease. There was no evidence of antibody-mediated cytotoxicity.
Lymphocyte-mediated myotoxicity in the active group was analyzed in relation to treatment and immunosuppression in six of the nine patients. Seven tests on patients on immunosuppressive therapy gave normal lymphocyte-mediated myotoxicity values of 1.0 ± 4.2 per cent (mean ± S.D.), whereas eight tests on patients who were on less than immunosuppressive therapy yielded elevated lymphocyte-mediated myotoxicity: 24.4 ± 10.6 per cent, with a significant difference between these two groups (p < 0.001). These data suggest that the pathogenesis of polymyositis involves a cell-mediated immunologic reaction directed against skeletal muscle, and that immunosuppressive therapy may exert its clinical effect by decreasing lymphocyte myotoxicity.
|Publication Type:||Journal Article|
|Publisher:||Massachusetts Medical Society|
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