title: Type 1 reactions in leprosy--heterogeneity in T-cell functions related to the background leprosy type.
abstract: Nineteen each of paucibacillary borderline tuberculoid (BT) and multibacillary borderline borderline (BB)/borderline lepromatous (BL) leprosy patients undergoing type 1 reactions were compared with nonreactional stable patients of the appropriate leprosy type. In the BT reactional group, both phytohemagglutinin-induced and, more importantly, antigen-induced lymphoproliferation was reduced in 80%-90% of the patients. On the other hand, leukocyte migration inhibition was reduced in 40% and remained unchanged in the others. Suppressor-cell activity as evaluated by a costimulant assay was also reduced in a majority of the reactional BT individuals. In contrast, the bacilliferous BB and BL patients in reaction showed significant general improvement in leukocyte migration inhibition (p less than 0.001) and antigen-induced lymphoproliferation (p less than 0.05) as compared to the expected hyporesponsive/anergic uncomplicated BB-BL patients. Suppressor-cell activity also recovered during the reactional phase. However, no significant differences were observed in either of the reactional or stable leprosy types in the numbers of total T cells (OKT3+) and their subsets as defined by OKT4+ (helper/inducer) and OKT8+ (suppressor/cytotoxic) functional phenotypes. Moreover, during type 1 reactions the 48-hr delayed-type hypersensitivity (DTH) responses after intradermal injection of Mycobacterium leprae antigens continued to reflect the background leprosy type rather than the functional perturbations in the circulating T cells. Only a marginal increase in DTH was observed in some BT reactional individuals. No consistent pattern in the above in vitro T-cell-related responses was discernable in the same individuals 4-6 months after subsidence of reactions. The clinical entity of type 1 reactions encompassing paucibacillary and multibacillary leprosy shows a heterogeneity/dichotomy in T-cell responses which may reflect different immunological mechanisms underlying the reactional state.
mesh_terms: D000942:Antigens, Bacterial / Q000276:immunology; D002464:Cell Migration Inhibition; D004893:Erythema Nodosum / Q000276:immunology; D006801:Humans; D006968:Hypersensitivity, Delayed; D007111:Immunity, Cellular; D007918:Leprosy / Q000276:immunology*; D007962:Leukocytes / Q000276:immunology*; D008213:Lymphocyte Activation; D009166:Mycobacterium leprae / Q000276:immunology; D010835:Phytohemagglutinins / Q000276:immunology; D012882:Skin Tests; D013601:T-Lymphocytes / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D010835:Phytohemagglutinins