Lesional T-cell subset in leprosy and leprosy reaction

Background The T-cell-mediated immune response plays an important role in leprosy. The in situ proportion and pattern of distribution of T-cell subsets in leprosy skin lesions have been studied, but no conclusion could be drawn. Methods We used monoclonal antibodies for T-helper and T-suppressor surface antigen to define the nature of dermal infiltration in 17 cases of nonreactional leprosy and 20 cases of reactional leprosy. Results We found T helper admired with T suppressor in an aggregated pattern in the granulomas of most cases of nonreactional leprosy and in type I reactional leprosy, but a diffuse infiltrate throughout the dermis of type II reactional leprosy. The T-helper/ suppressor ratio was 1.68 in tuberculoid and 1.5 in lepromatous cases. The T-helper/ suppressor ratios of borderline tuberculoid (3.11) and type I reactional leprosy (2.54) were not statistically different. The T-helper/suppressor ratio of type II reactional leprosy (5.83) was statistically higher than nonreactional lepromatous cases. Conclusions The alteration of the T-helper/suppressor ratio in our study is mainly due to the reduction of T-suppressor cells in the dermal infiltrates, especially in type II reactional leprosy. Further studies of T-suppressor functions may be important in the pathogenesis of leprosy.