Correlation Between IL-8 Gene Polymorphisms and Pathogenesis of Crohn's Disease.

Context: The risk of inflammatory bowel disease (IBD) is substantially heightened if patients' first-degree relatives have it. The genetic and immune factors related to the disease have attracted great attention, including patients innate genetic polymorphisms. Interleukin-8 (IL-8) plays a vital role in digestive-system diseases, especially in gastrointestinal diseases.

Objective: The study intended to explore the expression of interleukin-8 (IL-8) in the colon tissues of patients with Crohn's disease and the correlation between its polymorphisms and the disease's occurrence.

Design: The research team performed a prospective study.

Setting: The study took place in the Department of Gastroenterology at Zhuji People's Hospital of Zhejiang Province in Zhuji, China.

Participants: Participants were 100 patients with Crohn's disease at the hospital between November 2016 and June 2018 and 100 healthy individuals. The research team assigned participants with Crohn's disease to the Crohn's disease group and the healthy participants to the control group.

Outcome Measures: The research team: (1) determined differences in the protein expression of the IL-8 between the groups; (2) examined the conformity of the data to that of the Hardy-Weinberg equilibrium; (3) analyzed the differences in the genotypes and alleles for the IL-8 single nucleotide polymorphisms (SNPs) rs102039, rs103284 and rs105432 between the groups; and (4) for the Crohn's disease group, examined the differences in the disease's location and behavior for the participants with different genotypes.

Results: The protein expression level of IL-8 in the colon tissues in Crohn's disease group was significantly higher than that in control group (P < .05). The genetic association analysis showed significant correlations between the polymorphisms rs103284 and rs105432 and alleles of the IL-8 gene and the occurrence of Crohn's disease (P < .05), but no associations existed between the gene polymorphism rs102039 and alleles and Crohn's disease (P > .05). Significant correlations existed between the IL-8 gene polymorphisms rs103284 and rs105432 and the disease's location and behavior (P < .05).

Conclusions: IL-8 had a significantly increased expression in the colon tissues of the participants with Crohn's disease, and some genotypes and alleles for the gene polymorphisms rs103284 and rs105432 were significantly higher in the Crohn's disease group than in the control group. In addition, the disease's location and behavior were significantly different for participants in the Crohn's disease group with different genotypes.