In Situ Characterization of Immune Cells in the Annular Lesion of Leprosy

Lee, Chang Woo; Lee, Hae Yung; Son, Sook Ja; Kim, Do Il

Abstract

To characterize the immunopathologic phenotype of the cells in the lesional ti.:sue and to further examine the mechanism of the development of the annular lesions in leprosy, we have studied immune cells (T lymphocyte and its subsets, Langerhans cells, and HLA-DR antigen expressing cells) at different anatomical sites inside, active border, and outside normal skin in the annular lesions of leprosy. We took biopsy specimens from 4 patients of BT type, then processed the specimens by the staining methods eif indirect immunoperoxidase with monoclonal antibodies. In the active border the number of T cell was over 50g of the total cells infiltrated in the dermis. Helper T cells were dominant in number, and about three fourths of the cells were positive for HLA-DR staining. In two patients they had expression of DR antigen on the surfaces of the keratinocytes in the epidermis, in contrast to that of the inside, even the intensities were not. strong. At the inside of the annular lesions T cells were about 40% and the ratio of helper/suppressor T cell was approxiinately 1: 1, However, HLA-DR positive immune cells were not more than 10g among the total infiltrates. Langerha,ns cells were increased in number and in size either in the border or at the inside of the annular lesions. With these results we presume that the T cell mediated imrnune responses against Mycobacterium leprae may play an important role in the formation and extension of the annular lesions in leprosy.