Punkae MahaisavariyaKanokvalai KulthananSupakan KhemngernSumruay PinkaewMahidol UniversityFaculty of Medicine, Siriraj Hospital, Mahidol University2018-09-072018-09-071999-06-14International Journal of Dermatology. Vol.38, No.5 (1999), 345-347001190592-s2.0-0033002458https://repository.li.mahidol.ac.th/handle/20.500.14594/25628Background: 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.Mahidol UniversityMedicineArticleSCOPUS10.1046/j.1365-4362.1999.00621.x