01917nas a2200313   4500000000100000008004100001260001300042653002700055653001500082653001400097653003500111653002000146653004100166653001100207653002300218653001300241653002100254653001200275653001800287100001600305700001100321700001600332700001100348245012300359300001000482490000700492520109000499022001401589       1988                            d  c1988 Sep10aAntibodies, Monoclonal10aCell Count10aEpidermis10aFluorescent Antibody Technique10aFrozen Sections10aHistocompatibility Antigens Class II10aHumans10aImmunity, Cellular10aKeratins10aLangerhans Cells10aleprosy10aT-Lymphocytes1 aThangaraj H1 aLaal S1 aThangaraj I1 aNath I00aEpidermal changes in reactional leprosy: keratinocyte Ia expression as an indicator of cell-mediated immune responses.  a401-70 v563 a<p>Significant epidermal changes were observed in lesions of leprosy patients undergoing type 1 (reversal) and type 2 (erythema nodosum leprosum, ENL) reactions. Using indirect immunofluorescence and frozen sections stained with the appropriate monoclonal antibodies, an increase in epidermal cell layers, the presence of Ia on keratinocytes, an increase in Langerhans' cell numbers, and scattered T cells within the epidermis were seen in both types of reactions. Although borderline tuberculoid patients with type 1 reactions showed the consistent presence of Ia on all keratinocytes, lepromatous patients undergoing ENL reactions showed only a patchy distribution. Taken together, these studies indicate that local T-cell activation leading to the production of terminal lymphokine, such as interferon-gamma, with subsequent induction of Ia on epidermal cells may be an important event in reactional leprosy states. It is of interest that the hitherto considered "anergic" lepromatous patients should recover temporary T-cell reactivity during the natural course of the disease.</p>  a0148-916X