IL-17A and IL-17F polymorphisms in rheumatoid arthritis and Sjogren's syndrome.

OBJECTIVE: The aim of this study was to evaluate the influence of Th17 polymorphisms on the susceptibility or severity of rheumatoid arthritis (RA) and Sjogren's syndrome (SS). MATERIALS AND METHODS: The study sample comprised 206 individuals of both genders divided into three groups: exclusive rheumatoid arthritis (RA-100 patients), rheumatoid arthritis and Sjogren's syndrome (RA/SS-31 patients), and healthy controls (C-75 individuals). All the individuals were submitted to clinical evaluation, unstimulated sialometry, and Schirmer test; some patients with RA were also submitted to minor salivary gland biopsy for definition of SS diagnosis. Saliva samples were collected for isolation of DNA and genotyping of Th17 genes; IL-17A (-197G/A) and IL-17F (7488T/C). RESULTS: IL-17A (-197G/A) and IL-17F (7488T/C) SNPs were not associated with susceptibility to RA or secondary SS (sSS, p > 0.05 for both SNPs). In addition, they did not influence RA activity or clinical markers of SS. CONCLUSION: IL-17A (-197G/A) and IL-17F (7488T/C) polymorphisms are not associated with the susceptibility nor to the severity of RA and sSS in the studied population. CLINICAL RELEVANCE: A better understanding of the pathogenesis of SS is demanded to an adequate treatment as well as to the development of new management strategies.