Comparison of the characteristics of infiltrates in skin and nerve granulomas of leprosy.
The characteristics of infiltrates in the dermal and neural granulomas from the same leprosy patients were compared by preparing a single cell suspension. Skin and nerve biopsies from 10 patients, 5 with tuberculoid and 5 with lepromatous leprosy were analysed. The granulomas contained lymphocytes and macrophages. Lymphocytes were the predominant infiltrating cells in the tuberculoid dermal and neural granulomas. A high proportion of lymphocytes in both the skin and nerve granulomas in these cases were activated T cells as they formed rosettes with sheep erythrocytes and expressed HLA-DR antigens. In contrast, lepromatous dermal and neural granulomas contained very few of these lymphocytes. Dermal and neural granulomas from both the types of leprosy contained mature macrophages as they were esterase positive, did not exhibit peroxidase activity and expressed HLA-DR antigens. These macrophages did not possess C3 surface receptors either. These findings suggest that the infiltrates in the skin and nerve granulomas of a given type of leprosy have similar characteristics.