Immunodeficiency in leprosy.

It is known that the impairment of cell-mediated immunity (CM) exists in lepromatous leprosy patients. This was shown by 1) delayed skin reaction to various test antigens, 2) decreased transformation of lymphocytes by various antigens, 3) delayed rejection of skin allograft, 4) decreased migration inhibitory fa-tor (MIF) formation, and 5) histologic study of the lymph node. In addition to these previous works, we have studied T and B lymphocytes in peripheral blood of leprosy patients; T cells by the technic of rosette formation, and B cells by staining surface immunoglobulins. The result of our study shows decreased numbers of T cells and increased numbers of B cells in peripheral blood of lepromatous patients. A the same time, we found that allogenic leukocyte infusion treatment reversed T and B-cell abnormalities. We know that repeated infusions of allogenic leukocytes dramatically brought about improvement of the clinical status of the patients, resolution of skin lesions, subsidence of erythema nodosum leprosum reaction, clearance of bacteria from the skin and lymph nodes, and reconstitution of peripheral lymph nodes.