Genetic and Epigenetic Role of IL-17A in Rheumatoid Arthritis

Abstract

Background: Previous studies have revealed an association between interleukin 17A (IL-17A) polymorphisms and the prevalence of rheumatoid arthritis (RA) in Japanese and Caucasian patients. It was hypothesized that IL-17A polymorphisms might also affect RA susceptibility in the Pakistani population. Methods: In this study, two polymorphisms including IL-17A SNPs rs8193036 and rs2275913 were examined in a case – control study of Pakistani population through Polymerase Chain Reaction - Restriction Fragment Length Polymorphism (PCR - RFLP). Methylation Specific PCR was followed by bisulfite conversion of genomic DNA to evaluate the methylation status of IL-17A promoter region Results: The study showed association value of 8.760 and the p value 0.0125 for the genotype data for SNP rs2275913. While no association was found between rs8193036 and RA (p = 0.5223). IL-17A rs2275913 (A>G) was found associated with decreased risk of RA. Methylation status of IL17A promoter showed statistically significant association to RA (p = 0.0001). Conclusion: The present study demonstrated that the IL17A SNP rs2275913 (A>G) significantly decreases the risk of RA. While no association was found between IL17A SNP rs8193036 (C>T) and risk of RA. Methylation status of the IL17A promoter region is significantly associated with the disease. However, these results were obtained from only a moderate-sized sample population. Replication of these findings in larger populations from diverse ethnicity are required to confirm these findings