Background/aims: Interleukin-1 beta (IL-1 beta) plays an important role in gastric inflammation and physiology. Functional polymorphisms of IL-1 beta gene have been related to different risks of gastric cancer and duodenal ulcer but their role in gastric ulcer remains unknown. In this study, we investigate a plausible association between gastric ulcer and the polymorphisms in the IL-1 beta and IL-1 receptor antagonist (IL-1RN) genes. The relationships among the cytokine genotyping, other environmental risks such as Helicobacter pylori infection and smoking, and clinical characteristics of gastric ulcer were also determined.
Methodology: Peripheral blood DNAs from 120 unrelated Taiwan Chinese patients with gastric ulcer and 238 ethnically matched healthy controls were genotyped for the promoter (position -31 and -511) and Taq I polymorphism (position +3954) in the IL-1 beta gene and the variable number of tandem repeats polymorphisms in intron 2 of the IL-1RN gene. The status of Helicobacter pylori infection was determined by serology.
Results: The seropositive rate of Helicobacter pylori (95/120 vs. 134/238, OR: 2.95, 95%CI 1.77-4.91), habitual smoking (67/120 vs. 82/238, OR: 2.40, 95%CI 1.54-3.77) and blood group O (63/120 vs. 98/238, OR: 1.55, 95%CI 1.0-2.41) were significantly higher in patients with gastric ulcer than controls. The distributions of allele frequencies of IL-1 beta (-31 C/T or -511 C/T or +3954) and IL-1RN were similar between patients with gastric ulcer and controls. No significant differences were observed, including those analyzed after stratification of the infected population and by the ulcer subgroup.
Conclusions: Our data suggested that Helicobacter pylori infection, cigarette smoking, and blood group O are risk factors of gastric ulcer and IL-1 beta or IL-1RN polymorphisms do not influence susceptibility to gastric ulcer in a Taiwanese population.