Influence of IL17A polymorphisms (rs2275913 and rs3748067) on the susceptibility to ulcerative colitis.

Interleukin-17A plays a role in tissue inflammation by inducing release of proinflammatory and neutrophil-mobilizing cytokines. We investigated the association between ulcerative colitis (UC) and polymorphisms of IL17A, rs2275913 (-197 G > A), and rs3748067 (*1249 C > T). The study was performed in 475 healthy subjects (controls) and 202 with UC (UC cases), including 113 controls and 64 UC cases from previous study. We employed the multiplex PCR-SSCP method to detect gene polymorphisms. The minor allele frequency of rs2275913 was significantly higher but that of rs3748067 was significantly lower in UC cases than controls. The rs2275913 minor homozygote (AA) had an increased risk of the development of UC, whereas rs3748067 minor carrier (CT + TT) had decreased risks for the development of UC. When compared with LR group (rs2275913 GG + GA with rs3748067 CT + TT), HR group (rs2275913 AA with rs3748067 CC) had a more increased risk of the development of UC (OR, 3.38; p = 0.0007). The polymorphisms of IL17A were associated with the noncontinuous and pancolitis phenotypes of UC. Our results suggest that IL17A polymorphisms (both rs2275913 and rs3748067) influence the susceptibility to and pathophysiological features of UC, coordinately.