IN-SITU CHARACTERIZATION OF THE HUMAN HOST RESPONSE TO LEISHMANIA-PANAMENSIS

Both host and parasite determinants influence the outcome of Leishmani a infections. Human host responses in cutaneous leishmaniasis of limit ed duration caused by a single species of the Viannia (V) subgenus wer e studied in skin biopsies obtained from lesions caused by Leishmania (V) panamensis in 31 male patients from the Colombian Pacific Coast, D ermal infiltrates and histopathologic changes were characterized using monoclonal antibodies and an indirect immunoperoxidase method. Dermal distribution of T-cell subpopulations and B-lymphocytes was nonrandom : CD4+ and CD8+ T cells were most frequent in the upper dermis, and B cells were most abundant in the lower dermis. Parasites, macrophages, and neutrophils were localized predominantly in the middermis. Multipl e regression analyses to establish associations between lesion type (u lcer, nodule, or papule), immune response data (Montenegro skin test, indirect fluorescence antibody test titers, lymphocyte blastogenesis). and particular cell populations demonstrated statistically significan t correlations between CD4+ lymphocytes and macrophages (p < 0.05). CD 8+ lymphocytes were associated with plasma cells (p < 0.001), as was t he presence of amastigotes (p < 0.05). These associations and the in s itu divergence of CD4 and CD8 ratios suggest that prognostic indicator s for disease evolution could be identified by prospective analysis of cellular relationships and response to therapy.