Serum tumor necrosis factor levels and disease dissemination in leprosy and leishmaniasis.

It has been suggested that tumor necrosis factor alpha (TNF alpha) may serve as an important antigen-independent host defense mechanism against parasitic organisms. Sera from 66 patients with leishmaniasis and 68 patients with leprosy, all from Ethiopia, were tested for TNF alpha using an enzyme-linked immunoassay. Sera from patients with the multi-parasitic/bacillary type of disease (visceral or diffuse cutaneous leishmaniasis and lepromatous leprosy), known to be associated with absent or low specific T cell response, contained significantly higher TNF alpha titers than those of patients with pauci-parasitic/bacillary disease (localized cutaneous leishmaniasis and nonlepromatous leprosy). High titers of TNF alpha in the absence of a functioning T cell response do not appear to confer resistance against Leishmania aethiopica and Mycobacterium leprae.