Studies on T cell subsets and functions in leprosy.
T cell subsets and T cell functions were explored in 31 leprosy patients with the following methods: determination of the percentages of the different T cell subpopulations defined by monoclonal antibodies directed at total T cells, helper T cells and suppressor/cytotoxic T cells; measurement of the in vitro proliferative responses to mitogens; study of the concanavalin A-induced suppressive activity, assessed on MLC; measurement of delayed-type hypersensitivity by skin testing. The confrontation between immunological lepromatous patients without type-2 reaction (erythema nodosum leprosum), (2) lepromatous patients without ENL (erythema nodosum leprosum), (2) lepromatous patients was recent ENL and (3) tuberculoid patients. Unexpectedly, groups 1 and 3, although differing strongly in their clinical status and their sensitivity to lepromin (absent in group 1 and strong in group 3), showed a similar immunological profile with a normal percentage of T cells and a normal distribution of T cells among the major T cell subset contrasting with a moderate decrease of proliferative responses to mitogens and impaired delayed-type hypersensitivity reactions. Concanavalin A-induced suppressive activity was type-2 reaction) strongly differed from both other groups, showing striking abnormalities other groups, showing striking abnormalities of the repartition of the T cell subsets, with increased percentages of helper T cells and decreased percentages of suppressor T cells, and elevated proliferative responses to mitogens. Concanavalin A-induced suppressive activity was reduced in most patients of this group. It is suggested that this imbalance between T cell subsets contributes to the occurrence of ENL reactions in lepromatous patients.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D006801:Humans; D007428:Intradermal Tests; D007918:Leprosy / Q000276:immunology*; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000145:classification* / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D000911:Antibodies, Monoclonal; D003208:Concanavalin A