Evaluation of IL17A expression and of IL17A, IL17F and IL23R gene polymorphisms in Brazilian individuals with periodontitis.

The IL23/Th17 axis plays an important role in the pathogenesis of cell-mediated tissue damage caused either by autoimmunity or immune responses against bacterial infection. Single nucleotide polymorphisms in the IL17A, IL17F and IL23R genes have been associated with several inflammatory diseases. However, these polymorphisms have not yet been studied in periodontitis. The aim of present study was to evaluate the expression of IL17A and occurrence of the IL17A (rs2275913), IL17F (rs763780) and IL23R (rs11209026) gene polymorphisms in different clinical forms or severity of periodontitis in a sample of Brazilian individuals. Peripheral blood was obtained from 30 non-smoker individuals and analyzed by flow cytometry to determine IL-17 expression. Genomic DNA was obtained from oral swabs in 180 individuals and analyzed by Real-time PCR. The study group was composed by individuals without periodontitis (control), with aggressive periodontitis (AP) and with chronic periodontitis (CP). Higher frequency of IL17A+CD4+ T cells was observed in control group. The A+ genotype from IL17A (rs2275913) was associated with lack of disease. No association was found considering the IL17F and IL23R polymorphisms. Our data suggest that IL17A and the presence of IL17A (rs2275913) A allele are associated with the absence of periodontal disease.