Associations between Gene Polymorphisms in Pro-inflammatory Cytokines and the Risk of Inflammatory Bowel Disease: A Meta-analysis

Abstract

ABSTRACT The relationships between polymorphisms in pro-inflammatory cytokines and the risk of inflammatory bowel disease (IBD) remain discrepant. Therefore, the authors conducted a meta-analysis to robustly explore relationships between polymorphisms in pro-inflammatory cytokines and the risk of IBD by integrating the results of previous works. Medline, Embase, Wanfang, VIP and CNKI were searched throughly for eligible studies, and 35 genetic association studies were finally included in this meta-analysis. We noticed that genotypic frequencies of IL-1B rs1143627, IL-6 rs1800795 and IL-8 rs4073 polymorphisms among cases with IBD and population-based controls differed significantly. Moreover, we found that genotypic frequencies of IL-1B rs1143627 and IL-6 rs1800795 polymorphisms among cases with IBD and population-based controls of Caucasian origin differed significantly, whereas genotypic frequency of IL-8 rs4073 and IL-18 rs187238 polymorphisms among cases with IBD and population-based controls of Asian origin also differed significantly. Furthermore, we also noticed that genotypic frequency of IL-18 rs187238 polymorphism among cases with Crohn’s disease (CD) and population-based controls differed significantly. In conclusion, this meta-analysis demonstrated that IL-1B rs1143627 and IL-6 rs1800795 polymorphisms were significantly associated with the risk of IBD in overall population and Caucasians. Moreover, IL-8 rs4073 polymorphism was significantly associated with the risk of IBD in overall population and Asians. In addition, we also noticed that IL-18 rs187238 polymorphism was significantly associated with the risk of CD, and IL-18 rs1946518 polymorphism was significantly associated with the risk of IBD in Asians.