American Cutaneous Leishmaniasis, Lepromatous Leprosy, And Pulmonary Tuberculosis Coinfection With Downregulation Of The T-Helper 1 Cell Response

Cutaneous leishmaniasis, leprosy, and tuberculosis are caused by intracellular pathogens whose development depends on impaired cell-mediated immunity. We report an exceptional triple association of American cutaneous leishmaniasis, lepromatous leprosy, and pulmonary tuberculosis in a man with no recognized immunodeficiency. Normal immunological assessment of the interferon-gamma pathway does not support the hypothesis of a genetic defect in any of the genes involved in the T helper (Th)-1 cytokine cascade in this patient. Unresponsiveness to interleukin (IL)-12 of his T cells after stimulation with Leishmania guyanensis, Mycobacterium bovis bacille Calmette-Guerin, and Mycobacterium leprae antigens suggested the inability to mount an appropriate Th cell response to upregulate the IL-12 receptor expression.