Regulatory T-cell profile in early and late lesions of cutaneous leishmaniasis due to Leishmania major.

Cutaneous leishmaniasis (CL) is a public health problem in several endemic countries. Recent studies on mouse model and also a few clinical experiments showed that the type of immune response generated at the site of infection and especially balance between regulatory and effector T-cells determines the outcome of the disease toward self-limiting or long-lasting lesions. The aim of this study was to evaluate the role of natural regulatory T cells (nTregs) in early and late cutaneous lesions of human Leishmania major (L. major) infection. Skin biopsies were collected from parasitologically proven lesions of 28 CL patients, divided into two groups of early and late lesions. The causative agents were identified to be L. major. Quantitative real-time reverse transcription polymerase chain reaction (PCR) and immunofluorescent staining of biopsies were used to assess the Foxp3 mRNA expression and frequency of nTregs in two groups. Mann-Whitney U test was used to determine the significance of deference between the two groups. Mean relative expressions of Foxp3 mRNA were 0.53 ± 0.23 and 1.26 ± 0.99 in early and late lesions, respectively, which was significantly upper in chronic lesions (P = 0.007). Parallel results were obtained in tissue staining method. Increased in gene expression and protein staining of nTreg markers in chronic biopsy samples indicates a role for these cells in chronic L. major induced leishmaniasis and supports the effectiveness of regulatory T cell-based immunotherapy for treatment of chronic CL.