Lesional T‐cell subset in leprosy and leprosy reaction

Abstract 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 admixed 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.