Isolation and characterization of cells in granulomas of nerves of leprosy patients.

Single cell suspension from the granulomas in nerves of leprosy patients were prepared for an in vitro study of the properties of infiltrating cells. Nerve biopsies from 17 patients with tuberculoid (n = 9) and lepromatous (n = 8) leprosy cases were analysed. The granulomas were found to contain lymphocytes and macrophages. Lymphocytes were the predominant infiltrating cells in the tuberculoid nerves. In contrast, lepromatous nerves contained very few of these cells. The majority of lymphocytes in tuberculoid granulomas were activated T cells as they formed rosettes with sheep erythrocytes, exhibited esterase dots in the cytoplasm and expressed HLA-DR antigens. A small proportion of the lymphocytes also formed rosettes with EAC. Most macrophages from both the granulomas were mature macrophages as they were esterase positive, did not exhibit peroxidase activity and expressed HLA-DR antigens. The macrophages did not possess C3 surface receptors.