Cell-mediated immunity in leprosy and transfer of delayed hypersensitivity reactions

Eighty-nine patients with leprosy, 65 classified as lepromatous and 24 as tuberculoid, were examined in this study. Skin test responses to protein antigens and dinitrochlorobenzene (DNCB) were depressed in lepromatous patients compared to controls. Tuberculoid patients did not exhibit a significant depression to microbial antigens, but they showed a definite depression in the ability to be sensitized with DNCB. The transfer of delayed hypersensitivity reactions to tuberculin, trichophytin, and lepromin (Fernandez and Mitsuda reactions) was accomplished in lepromatous and indeterminate leprosy patients using viable lymphocytes from donors presenting positive reactions to these antigens. The lepromin reaction was also transferred to patients with South American blastomycosis and cutaneous leishmaniasis. The positive reactions of adoptive immunity were confirmed by histologic examination of skin biopsies.