Disturbance of the Blood T:B Lymphocyte Ratio in Lepromatous Leprosy

Abstract

A significant increase in absolute numbers of bone-marrow-derived (B) lymphocytes and a significant decrease in the absolute numbers of lymphocytes forming spontaneous rosettes with sheep red blood cells (thymus derived [T] lymphocytes) were observed in peripheral blood among a group of 17 patients with lepromatous leprosy. Lymphocyte response to phytohemagglutinin after three days of culture was significantly reduced in the patient group. A generalized impairment of delayed hypersensitivity responses was observed among our patients as manifested by skin-test anergy to lepromin and fungal antigens. These findings suggest that anergy of the cellular immune system in patients with lepromatous leprosy may be secondary to the destruction of T lymphocytes or disturbance of their recirculation. (N Engl J Med 288:1036–1039, 1973)