The Influence of Polymorphisms of Interleukin-17A and Interleukin-17F Genes on the Susceptibility to Ulcerative Colitis

We investigated the association between ulcerative colitis (UC) and polymorphisms of IL-17A (rs2275913, G-197A) and IL-17F (rs763780, 7488T/C) genes. We employed the multiplex PCR-SSCP method to detect gene polymorphisms. Both the numbers of -197A (IL-17A) and 7488T (IL-17F) alleles were significantly correlated to the development of UC. The frequencies of -197A/A and 7488T/T genotypes in the UC group were significantly higher than those in the non-UC group. An adjusted analysis revealed that -197A and 7488T alleles were independent risk factors for the developing UC. In addition, both polymorphisms were significantly associated with the pancolitis phenotype. Furthermore, -197A allele was significantly correlated to the chronic relapsing phenotype and -197A/A homozygote was more frequent in steroid-dependent cases, whereas 7488T allele was correlated with the chronic continuous phenotype. Our results provided the first evidence that -197A (IL-17A) and 7488T (IL-17F) alleles may influence the susceptibility to and pathophysiological features of UC independently.