Interleukin-1 and TNF-alpha polymorphisms and Helicobacter pylori in a Brazilian Amazon population.

AIM

To study the association between Interleukin-1 (IL-1) and tumor necrosis factor (TNF)-alpha polymorphisms, infection by Helicobacter pylori (H pylori) and the development of gastrointestinal diseases.

METHODS

Genomic DNA was extracted from the peripheral blood of 177 patients with various gastrointestinal diseases and from 100 healthy volunteers. The polymorphisms in IL-1beta and TNF-alpha genes were analyzed using the polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) and those from IL-1RN with PCR. The presence of infection due to H pylori and the presence of the CagA toxin were detected by serology. The histopathological parameters in the gastric biopsies of the patients were according to the Sydney classification.

RESULTS

A comparison of the frequencies of the different polymorphisms studied among the patients and the control group demonstrated that the allele IL-1RN2 was more frequent among patients with gastric ulcers and adenocarcinoma. Carriers of the allele IL-RN2 and those with reactive serology for anti-CagA IgG had a greater risk of developing peptic ulcer and gastric adenocarcinoma, as well as a higher degree of inflammation and neutrophilic activity in the gastric mucosa.

CONCLUSION

Our results indicate a positive association between IL-1RN gene polymorphism and infection by positive H pylori CagA strains and the development of gastric ulcers and adenocarcinoma.