Characterization of the local and systemic immune responses in patients with cutaneous leishmaniasis due to Leishmania major.

In this study skin biopsies and peripheral blood samples were obtained from patients with cutaneous leishmaniasis caused by Leishmania major. Samples were obtained at diagnosis and during healing when the lesions had regressed to half the original size. At diagnosis most of the cells expressed HLA-DR. The numbers of CD8+ cells in the lesions were higher at diagnosis than during healing. By contrast, a lower percentage of PBMC expressed CD8+ cells at diagnosis probably due to sequestration in the lesion. In the lesion, in situ staining for IFN-gamma, IL-10, and IL-4 showed marked variation between all patients in the number of positive cells for a particular cytokine. The proliferative response of PBMC to leishmanial antigens and IFN-gamma production tended to increase during healing. Cytokine patterns in the PBMC in response to Leishmania antigen was more specific than in the lesion and correlated better with the clinical manifestations. Possible reasons for this are discussed.