Monoclonal antibodies to human leucocyte antigens in polymyositis and muscular dystrophy

Biopsy specimens from patients with treated or untreated polymyositis and muscular dystrophy controls were examined by indirect immunoperoxidase staining with a panel of monoclonal antibodies to human leucocyte antigens. In untreated polymyositis, helper/inducer T cells were the predominant T cell subset. In treated cases few T cells were seen. Overall, few T cells were seen in dystrophic cases, most infiltrating cells being dendritic and lacking T cell antigens. Staining of sarcolemma with anti-HLA class 1 antibody is weak or negative except in areas adjacent to infiltrating leucocytes or where muscle fibre damage is apparent.