The Association Of TNF Gene Polymorphisms With Helicobacter Pylori Infection In Gastroduodenal Diseases

Background Helicobacter pylori (H. pylori) is a major cause of chronic gastritis and duodenal ulcer disease, and a definite carcinogen for gastric adenocarcinoma. However, the underlying pathogenic mechanisms have not been fully understood, although the interactions between environmental, bacterial and multiple genetic components are likely to be involved. Tumor necrosis factor (TNF) is a key cytokine involved in H. pylori-induced gastric inflammation.Aim The present study aimed to determine the di-allelic polymorphisms of TNF gene and their association with H. pylori infection and gastroduodenal diseases in Chinese population of Han nationality.Method Two hundred and thirteen patients with gastroduodenal diseases(mean age 54 years, range 18-88 years) and 264 healthy controls (mean age 48 years, range 21-54 years)were genotyped by the polymerase chain reaction - restriction fragment length polymorphism ( PCR-RFLP) method for TNF-a 308, lymphotoxin-a (LT-d) Ncol and AspHl gene polymorphisms. The gastroduodenal diseases include 73 chronic superficial gastritis, 78 duodenal ulcer and 59 noncardic gastric cancer and 3 cardie gastric cancer, the diagnosis of gastroduodenal diseases was based on endoscopic and histopathological examinations. H. pylori infection status was determined by a validated serological test. None of these subjects had a history of systemic lupus erythematosis, diabetes mellirus, rheumatoid arthritis, or inflammatory bowel disease.Results H. pylori infection was detected in 90.6% of 213 patients and 62.1% of 264 healthy controls (P<0.0001, Odds ratio=5.884, 95%CI: 3.486-9.931). Frequency of LT-a Ncol A/G genotype in patients with noncardia gastric cancer with H. pylori infection was significantly higher than that in H. pylori positive healthy controls (64.0% vs 46.0%, P=0.0297, OR=2.026, 95%CI: 1.080-3.803). The allele A frequencyof TNF-a 308 was 8% in chronic superficial gastritis, 8% in duodenal ulcer, but 3% in gastric cancer, which was not significantly different from that in the healthy controls (7%).There was no other association between LT- AspHI gene polymorphisms and H. pylori infection in gastroduodenal diseases.Conclusion LT- Ncol A/G genotype was positively associated with H. pylori infection in patients with noncardia gastric cancer in Chinese patients with Han nationality.