The Influence of Polymorphisms of Interleukin-17A and -17F Genes on Susceptibility and Activity of Rheumatoid Arthritis

The roles of interleukin (IL)-17A and IL-17F in the pathogenesis of rheumatoid arthritis (RA) have been previously studied. However, the relationships between polymorphisms (IL-17A G197A, the IL-17F 7488A/G, and the IL-17F 7383A/G) of these genes with RA have not been clarified yet. To investigate the impacts of these polymorphisms on the severity and susceptibility of RA in a Turkish population. One hundred sixty-one patients with RA and 88 healthy sex-, age-, and ethnicity-matched controls were enrolled in this study. The erythrocyte sedimentation rate, C-reactive protein (CRP), and disease activity scores 28 (DAS28) of all participants were recorded. The IL-17A G197A, the IL-17F 7488A/G, and 7383A/G polymorphisms were determined using the polymerase chain reaction-restriction fragment length polymorphism method. We found no significant difference regarding genotypes or allelic frequency distributions of the IL-17A G197A, the IL-17F 7383A/G, and 7488A/G polymorphisms between patients and healthy controls (p>0.05). There were slight, but not significant, differences in terms of CRP levels associated with the distribution of the genotypes of the IL-17F 7488A/G, and regarding DAS28 levels according to the genotype distribution of the IL-17A G197A polymorphism (p=0.062, 0.087, 0.052, respectively). These findings suggest that future larger scale studies with increased power should be performed to determine if the IL-17F 7488A/G and the IL-17A G197A polymorphisms are associated with the disease activity in patients with RA.