DEVELOPMENT OF INVITRO PARAMETERS OF CELL-MEDIATED-IMMUNITY IN THE COURSE OF HUMAN CUTANEOUS LEISHMANIASIS INFECTION

The goal of the present study was to determine whether a correlation b etween the clinical stage of cutaneous leishmaniasis lesions and in vi tro parameters of cell-mediated immunity could be established. For thi s purpose, we measured lymphocyte proliferation, using a total lymphoc yte proliferation (TLP) blood assay, and leishmanicidal effector activ ity using peripheral blood mononuclear cells (PBMC) in a three-day ass ay. The parameters of leishmanicidal activity measured included percen t infected monocytes and number of amastigotes per 100 infected monocy tes 24 and 72 hr after infection. Three groups of people were studied: a group of patients in the course of the disease, a group of immune i ndividuals, and unexposed controls. The results of the study suggested that the ability of PBMC to kill parasites increased in patients as t he lesions cured, and was highest in immune individuals. In contrast, the TLP response once positive, did not increase after cure. In approx imately 30% of the patients who were retested on several occasions dur ing the course of the disease, a positive response reversed to negativ e both in the TLP and the effector assays while the lesions were still active. In approximately 50% of these cases, the response eventually became positive again. The data presented show that effector activity and proliferation correlate with immunity, and suggest that marked het erogeneity characterizes the immune response in the course of active d isease.