Single nucleotide polymorphism of IL-17F as a possible biomarker of rheumatoid arthritis in the Russian population of the Chelyabinsk Region and its non-equilium linkage with IL-17A

The interleukin 17 (IL-17) family and its role in the immune response and various pathologies is studied in different research. IL-17A and IL-17F belong to proinflammatory cytokines and are the most studied members of the interleukin 17 family and have similar functions and the greatest activity. They play a key role in the immune response in autoimmune diseases, including rheumatoid arthritis. The key point in the regulation of the amount and functional activity of cytokines, including IL-17A and IL-17F, is polymorphism of their genes. Due to the fact that the polymorphism of the IL-17F gene 7488 T/C is located on chromosome 6 near the polymorphism of the IL-17A gene -197G/A and they both take part in the immunopathogenesis of RA, it is possible that their allelic variants are inherited linked and form haplotypes. The purpose of our study is to identify a possible association of IL-17F gene polymorphism with a predisposition to rheumatoid arthritis, including depending on the age and gender of patients in the Russian population of the Chelyabinsk region, as well as to assess the formation of IL-17A ~ IL-17F haplotypes in a group of patients in comparison with a group of conditionally healthy individuals. The result of our study reliably indicates that the homozygous genotype for the ancestral allele 7488 TT of the IL-17F gene (p 0.001) makes a huge contribution to the susceptibility to rheumatoid arthritis, including in the group of men. In addition, polymorphisms in the IL-17A and IL-17F genes are linked to each other and form two haplotypes. One of them, IL-17A -197*G ~ IL-17F 7488*C, is associated with a reduced risk of developing rheumatoid arthritis. This haplotype is formed by the ancestral allele of the IL-17A gene and the mutant allele of the IL-17F gene, which takes over the main function and reduces the protein activity level and probably thereby reduces the risk of developing RA.