Response of iNOS and its relationship with IL-22 and STAT3 in macrophage activity in the polar forms of leprosy

•Leprosy is a chronic granulomatous infection related to the immunological host response.•The macrophage is one of the central cells in response to M. leprae.•New evidence shows participation of new cytokines in the immune response in leprosy.•IL-22, transcription factors and macrophage activity contributes to the immune response to M. leprae.

Leprosy is a chronic granulomatous infection that manifests as different clinical forms related to the immunological response. The aim of the study was to evaluated the response of IL-22, STAT3, CD68 and iNOS in leprosy skin lesions. The mean number IL-22 positive cells was 12.12 ± 1.90 cells/field in the TT form and 31.31 ± 2.91 cells/field in the LL form. STAT3 positive cells was 5.29 ± 1.96 cells/field in the TT form, while this number was 11.13 ± 3.48 cells/field in the LL form. The mean number of CD68 positive cells was 25.18 ± 6.21 cells/field in the TT form and 62.81 ± 8.13 cells/field in the LL form. Quantitative analysis of iNOS revealed a significant difference, with the mean number of cells expressing the enzyme being 30.24 ± 2.88 cells/field in the TT form compared to 35.44 ± 4.69 cells/field in the LL form. Linear correlations in lesions of TT patients showed a moderate positive correlations between CD68 and iNOS, STAT3 and Inos, IL-22 and STAT3, and IL-22 and iNOS. Our results demonstrate that these factors can act synergistically to induce a microbicidal activity in the population of macrophages in the leprosy lesions.