European Journal of Dermatology


Decreased RNA expression of interleukin 17A in skin of leprosy Volume 22, numéro 4, July-August 2012

Programa de Pós-graduação em Imunologia Básica e Aplicada, Universidade Federal do Amazonas, Manaus, Brazil, Fundação de Hemoterapia e Hematologia do Amazonas, Manaus, Brazil, Instituto Leônidas e Maria Deane Fiocruz Amazônia, Manaus, Brazil, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil, Fundação de Dermatologia e Venereologia Alfredo da Matta, Manaus, Brazil, Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal do Amazonas, Manaus, Brazil

Interleukin-17A (IL-17A) is a proinflamatory cytokine that plays an important role in fighting pathogens at mucosal interfaces, by summoning neutrophils and upregulating cytoplasmatic antimicrobial peptides. So far, the presence of IL-17A in leprosy has not been demonstrated. The expression of IL-17A and related cytokines (IL-6 and IL-23p19) was addressed through RNA extraction and cDNA quantitative amplification in macerated biopsies of active lesions of 48 leprosy patients and 20 fragments of normal skin of individuals. Blood levels of IL-17A, IL-23p19 and IL-6 were determined by ELISA. We found an abrogated mRNA IL-17A response in all biopsies of leprosy patients, as compared with controls. Circulating IL-17A and IL-23p19 were undetectable in both patients and controls, but IL-6 was higher in lepromatous patients. Although at low levels, IL-17A mRNA in lepromatous patients had an inverse linear correlation with bacillary burden. Low expression of IL-17A in patients may be a constitutive genetic feature of leprosy patients or a circumstantial event induced by the local presence of the pathogen, as an escape mechanism.