Background: Gastric atrophy induced by Helicobacter pylori is thought to predispose patients to noncardiac gastric cancer development. However, the host genetic factors that influence the progression of gastric atrophy have not been elucidated. In this study, we examined the effects of cytokine polymorphisms on H. pylori-induced gastric atrophy.
Methods: Blood samples were taken from 454 Japanese subjects. The interleukin-2 (IL-2; T-330G), IL-4 (C-33T), and IL-13 (C-1111T) polymorphisms were genotyped by polymerase chain reaction with confronting two-pair primers (PCR-CTPP). Anti-H. pylori IgG antibody and pepsinogen I and II were measured to diagnose H. pylori infection and atrophic gastritis.
Results: The odds ratios (ORs) for the association between IL-2 polymorphism [OR = 2.78, 95% CI (confidence interval) = 1.26-6.17 (T/T to G/G)] or IL-4 polymorphism [OR = 2.22, 95% CI = 1.01-4.89 (T/C to C/C)] were increased significantly with gastric atrophy, whereas the corresponding OR of IL-13 polymorphism was decreased with gastric atrophy [OR = 0.61, 95% CI = 0.39-0.96 (C/T and T/T to C/C)]. There were no significant H. pylori seropositivity-related differences between these polymorphisms. We examined the relationship between these polymorphisms and gastric atrophy separately in H. pylori-seropositive and -seronegative groups. In the H. pylori-seropositive group, the IL-2 T/T (OR = 2.78, 95% CI = 1.12-6.93) had a significant association with gastric atrophy.
Conclusions: These results reveal that the IL-2 gene polymorphism is associated with an increased risk of gastric atrophy induced by H. pylori infection and might predispose to gastric cancer.