title: The cutaneous infiltrates of leprosy: cellular characteristics and the predominant T-cell phenotypes.
abstract: We report on the characteristics of cells in the cutaneous lesions and blood of 21 patients with lepromatous, tuberculoid, and intermediate forms of leprosy. A large proportion of the infiltrates in lepromatous lesions consist of macrophages heavily parasitized with Mycobacterium leprae. The T cells in the lesions are devoid of OKT4/Leu 3a-positive ("helper") cells and consist almost exclusively of OKT8/Leu 2a-positive ("suppressor") populations. In contrast, the tuberculoid infiltrates contain well-organized epithelioid and giant-cell granulomas and only remnants of bacilli, and the predominant T cell is from the OKT4/Leu 3a-positive subset. In both tuberculoid and lepromatous infiltrates, T cells and macrophages expressed HLA-DR antigen. No marked alteration in the distribution of blood T-cell phenotypes was noted. We conclude that there is a marked difference between T-cell subsets in lepromatous and tuberculoid infiltrates, which may influence the microbicidal activity of macrophages in the lesions.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007918:Leprosy / Q000097:blood / Q000276:immunology / Q000473:pathology*; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D009166:Mycobacterium leprae / Q000302:isolation & purification; D010641:Phenotype; D012867:Skin / Q000473:pathology* / Q000648:ultrastructure; D013601:T-Lymphocytes / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II