IMMUNOMODULATION OF CHICLERO ULCER - ROLE OF EOSINOPHILS, T-CELLS, TUMOR-NECROSIS-FACTOR AND INTERLEUKIN-2

The progression of cutaneous leishmaniasis is controlled largely by ce ll-mediated immunity. Two subpopulations of CD4(+) T cells exist that control healing or immunopathology of murine and, perhaps, human leish maniasis. To better understand the immunological pathways controlling outcome of the human disease, we analysed the pattern of tumour necros is factor (TNF) and interleukin-2 (IL-2), bath of which were present i n the sera of humans with active or healed chiclero's ulcer, in relati on to the development of delayed-type hypersensitivity (DTH) responses and leucocyte counts in peripheral blood. Increased serum levels of I L-2 and TNF-or were apparent only in individuals with active lesions. All individuals with localized cutaneous leishmaniasis developed a str ong DTH. The number of T cells was lower in the blood of diseased indi viduals and the CD4/CD8 ratio was reduced (from 1.5 to 1.0) when compa red with the control group. However, diseased and recently cured indiv iduals developed eosinophilia. We conclude that important alterations of the immune response exists in humans suffering from this normally s elf-healing infection.