Association of the interleukin-22 genetic polymorphisms with ulcerative colitis

BACKGROUND: Interleukin-22 (IL-22) is a member of the IL-10 family of anti-inflammatory cytokines that mediates epithelial immunity. IL-22 expression was found to be increased in patients with ulcerative colitis (UC). Whether genetic polymorphisms of IL-22 also influence UC risk is still unknown. The purpose of this study was to investigate the association between the IL-22 gene polymorphisms (−429 C/T, +1046 T/A and +1995 A/C) and the risk of UC in Chinese Han patients. METHODS: This hospital-based case–control study comprised 180 patients with UC and 180 age- and gender-matched controls. Genotypes of 3 common polymorphisms of the IL-22 gene were determined by fluorogenic 5′ exonuclease assays (TaqMan). RESULTS: Patients with UC had a significantly higher frequency of IL-22 −429 TT genotype [odds ratio (OR) =2.43, 95% confidence interval (CI) = 1.35, 4.37; P = 0.003] and −429 T allele (OR =1.54, 95% CI = 1.14, 2.07; P = 0.004) than controls. The findings are still emphatic by the Bonferroni correction. The IL-22 +1046 T/A and IL-22 +1995 A/C gene polymorphisms were not associated with a risk of UC. When stratifying by clinical type, location and disease severity of UC, no significant differences were found in any groups. CONCLUSION: This is the first study to provide evidence for an association of IL-22 −429 C/T gene polymorphisms with UC risk. Additional well-designed large studies were required for the validation of our results. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_183