FRIDAY, Aug. 27 (HealthDay News) -- Researchers have identified a subgroup of necrotizing myopathy patients with novel autoantibodies who are potential candidates for immunosuppressive therapy, according to a study in the September issue of Arthritis & Rheumatism.
Lisa Christopher-Stine, M.D., of the Johns Hopkins University School of Medicine in Baltimore, and colleagues evaluated muscle biopsy and serum samples from 225 patients with myopathy. The researchers determined antibody specificities by performing immunoprecipitations, and stained and examined some biopsies for tissue characteristics.
The investigators identified 26 patients who had necrotizing myopathies of uncertain origin, and screened their blood samples for the presence of novel autoantibodies. In 16 patients, they discovered a unique autoantibody specificity against 200-kDa and 100-kDa proteins (anti-200/100 autoantibodies). Based on clinical and muscle biopsy characteristics, the researchers determined those patients probably had autoimmune myopathies that were responsive to immunosuppressants. The researchers found that 63 percent of the anti-200/100 autoantibody group had undergone statin therapy prior to muscle symptoms, including nearly 90 percent of those age 50 or older.
"An anti-200/100 kDa specificity defines a subgroup of necrotizing myopathy patients previously considered to be 'autoantibody negative.' We propose that these patients have an immune-mediated myopathy which is frequently associated with prior statin use and should be treated with immunosuppressive therapy," the authors write.
Abstract
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