Protective role of interleukin-19 gene polymorphisms in patients with ulcerative colitis.

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) of unknown etiology. Interleukin (IL)-19 belongs to the IL-10 family and is a potent immunomodulatory cytokine, with implications for pathogenesis in IBD. No previous studies have reported this novel association between UC and IL-19 polymorphisms. In the present work, the role of IL-19 gene polymorphisms as susceptibility markers for UC was evaluated. Three polymorphisms of IL-19 gene (rs2243188, rs2243191, and rs2243193) were genotyped by 5' exonuclease TaqMan genotyping assays on an ABI Prism 7900 HT Fast Real-Time PCR System in a group of 200 Mexican Mestizo patients with UC and 698 healthy unrelated individuals with no family history of UC. The rs2243191 polymorphism significantly deviated from Hardy-Weinberg equilibrium (HWE) (p < 0.05) and consequently was not included in the analysis. Although genotypes AA (rs2243188) and AA (rs2243193) were significant decreased in UC patients as compared with healthy controls (p(c) = 0.018 and p(c) = 0.006, respectively), a genetic additive effect for the alleles was not observed (Cochran-Armitage trend test, not significant). In the subgroup analysis, no differences were found between the IL-19 genotypes and the clinical characteristics of UC. The results suggest that IL-19 polymorphisms (rs2243188 and rs2243193) might have a protective role in the development of UC in Mexican individuals.