ABERRANT IMMUNOREGULATORY CONTROL OF LYMPHOCYTE-B FUNCTION IN LEPROMATOUS LEPROSY

Abstract

The capacity of peripheral blood mononuclear (PBM) cells from patients with leprosy to generate Ig-secreting cells in response to pokeweed mitogen (PWM) was evaluated by a reverse hemolytic plaque forming cell (PFC) assay. The PFC responses of PBM cells from patients with lepromatous (Lpr) leprosy were significantly higher (P < 0.01) than those of PBM cells from normal controls and patients with tuberculoid leprosy. Co-culture of T lymphocytes from normal donors with PBM cells from Lpr patients reduced the PFC response of these cells to the normal range. T4+-helper lymphocytes from Lpr donors did not induce supranormal responses to PWM by normal PBM cells enriched for B lymphocytes. T8+-suppressor lymphocytes from normal donors greatly reduced the response of cultures containing normal allogeneic B cells plus T4+ cells. Conversely, when T8+ cells from Lpr donors were cocultured with normal B cells plus T4+ cells, they failed to suppress the response to PWM. Thus, abnormally high PWM-stimulated PFC responses by B lymphocytes from patients with Lpr leprosy were demonstrated. This aberration, in turn, is apparently associated with a loss of regulatory function by T8+-suppressor cells in Lpr patients.