BACKGROUND: Leprosy is a chronic granulomatous disease caused by Mycobacterium leprae. Among the immunopathological aspects of leprosy is known that the defense is done by the cellular immune response, able to phagocyte and destroy the bacilli, mediated by cytokines and mediators from oxidation. The long-standing concept of a Th1-Th2 dichotomy in leprosy, with predominant Th1 in tuberculoid lesions and Th2 predominant in virchowian pacients, has recently been challenged. Furthermore, the Th22 response was identified as modulating Th1-Th2 in inflammatory skin diseases, but their roles in leprosy have not yet been elucidated. OBJECTIVE: Evaluate the tissue expression of cytokines involved in Th22 response in the polar forms of leprosy. METHOD: Patients with dermato-immunological diagnosis of leprosy were included and selected 31 patients, 16 with the tuberculoid (TT) form and 15 with lepromatous (LL). Immunohistochemistry for tissue immunostaining with antibodies against IL-13, IL-22, TNF-α and FGF-b was based on the method involving the formation of biotin-streptavidin peroxidase complex. Quantitation of the immunostaining was taken randomly from 05 fields viewed at 400x magnification microscope. In univariate analysis, frequencies, measures of central tendency and dispersion were obtained and for investigation of the hypothesis were applied the Mann-Whitney test and the Pearson correlation, considering a significance level of 5% (p ≤ 0.05). RESULTS: Regarding the immunostaining for IL-22 can be observed statistical difference among the groups and in the LL pole the average was 241.3 ± 44.63 cells/mm2, while in the TT form the mean was 90.39 ± 30.18 cells/mm2 (p <0.0001). Engaging the presence of IL-13, LL pole average occurrence was 85.76 ± 19.99 cells/mm2. In the TT pole the mean was 57.20 ± 14.73 cells/mm2 (p = 0.0002). Regarding the immunostaining for FGF-b, in the LL lesions, the mean incidence was 228.9 ± 45.13 cells/mm2, while in the TT form the mean was 47.80 ± 14.29 cells/mm2 (p <0,0001). For TNF-α, quantitative analysis was statistically significant in TT form where the average of the cells expressing the cytokine was 99.74 ± 30.14 cells/mm2 when compared to the LL form where the results were 62.08 ± 13.67 cells/ mm2 (p = 0.0008). CONCLUSION: The Th-22 response, mediated by IL-22, has fundamental importance in the pathogenesis of leprosy, relating directly to the clinical form of the disease and other cytokines.
|
