In vitro studies on dermal granulomas of human leprosy: characterization of cells using monoclonal antibodies.

Single cell suspensions from granulomas of leprosy cases were prepared to enable an in vitro study on the characteristics of infiltrating cells. In all, biopsies from 21 untreated cases of tuberculoid leprosy and lepromatous leprosy were analyzed. The granulomas were found to contain lymphocytes and macrophages. The numbers of lymphocytes were higher in the suspensions of tuberculoid granulomas in comparison to lepromatous granulomas. A high percentage of lymphocytes from tuberculoid granulomas expressed OKT11 and Ia-like antigens, thereby indicating the presence of activated T cells. The proportion of Leu3a+ cells was greater in comparison to OKT8+ cells in these granulomas. In lepromatous granulomas, only a few positive lymphocytes expressing OKT11 or OKT8 antigens were observed. The ratio of Leu3a+:OKT8+ cells (2.79 +/- 0.61) was higher in the tuberculoid granulomas than in the lepromatous granulomas. Most macrophages from both types of granulomas expressed Ia-like antigens.