title: Immunocytochemical and virological characteristics of HIV-associated inflammatory myopathies: similarities with seronegative polymyositis.
abstract: We performed an immunoperoxidase study on muscle biopsy specimens from 19 patients with polymyositis who were seropositive for human immunodeficiency virus (HIV) (21 specimens) and 5 HIV-seronegative patients with polymyositis and compared the findings. A quantitative analysis of T cells and T-cell subsets, B cells, natural killer cells, interleukin-2 receptor-positive cells, and macrophages was performed on serial sections from all the specimens. Localization of major histocompatibility complex (MHC)-I and -II antigens, alpha and gamma interferon, and HIV antigens (p24, gp120, and gp41) was performed using specific antisera. In specimens from HIV-positive and seronegative patients, the predominant cell population was CD8+ cells and macrophages invading or surrounding healthy muscle fibers that expressed MHC-I antigen on their surface. The endomysial infiltrates in specimens from HIV-positive patients differed from those seen in specimens from the seronegative patients only by a significant reduction of the CD4+ cells (12.6 +/- 3.2% versus 21.1 +/- 4.2%). HIV antigens were seen in occasional interstitial mononuclear cells (but not in muscle fibers) in 6 of the 21 specimens from HIV-positive patients. Interferon was not localized. We conclude that the development of HIV-associated polymyositis does not appear to be related to direct infection of the muscle fibers by HIV but rather is due to a T-cell-mediated and MHC-I-restricted cytotoxic process, perhaps triggered by HIV. Because this immunopathological mechanism is common in both HIV-associated polymyositis and polymyositis alone, it is suggested that viruses may also be responsible in triggering polymyositis.
authors.affiliation: Neuromuscular Diseases Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
authors.forename: I
authors.initials: I
authors.lastname: Illa
authors.forename: A
authors.initials: A
authors.lastname: Nath
authors.forename: M
authors.initials: M
authors.lastname: Dalakas
mesh_terms: D000293:Adolescent; D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D015488:HIV Antigens / Q000032:analysis; D015658:HIV Infections / Q000150:complications* / Q000188:drug therapy; D006679:HIV Seropositivity; D006801:Humans; D007124:Immunoenzyme Techniques; D008264:Macrophages / Q000276:immunology; D008875:Middle Aged; D009220:Myositis / Q000188:drug therapy / Q000382:microbiology / Q000473:pathology*; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000473:pathology; D015215:Zidovudine / Q000627:therapeutic use
chemical_list: D015703:Antigens, CD; D015488:HIV Antigens; D015215:Zidovudine