TNF-alpha expression in gastric mucosa of individuals infected with different virulent Helicobacter pylori strains.

BACKGROUND: Helicobacter pylori colonizes the human gastric mucosa, leading to chronic superficial gastritis and in some cases to peptic ulceration, gastric adenocarcinoma, or gastric lymphoma. It has been postulated that the clinical outcome depends on differences in H. pylori strain virulence as well as on individual factors of the host. Thus, we aimed to assess the relation between H. pylori cagA/vacA genotypes and the TNF-alpha gene expression in gastric mucosa specimens from patients with chronic gastritis.

MATERIAL/METHODS: This study was conducted with gastric mucosa samples obtained during gastroendoscopy from 43 H. pylori-infected individuals with chronic gastritis. The presence of ureA and cagA genes and vacA allele combinations were analyzed in isolated DNA by the polymerase chain reaction method. Isolates of RNA were used for cDNA synthesis by reverse transcription. Synthesized cDNA was used to determine the TNF-alpha gene expression level by quantitative real-time polymerase chain reaction assay.

RESULTS: The cagA gene was detected in 67.44% of H. pylori strains. Five vacA alleles in the tested H. pylori strains were detected: s1a/m1 (18.60%), s1a/m2 (23.26%), s1a/m3 (18.60%), s1b/m2 (6.98%), and s2m2 (32.56%). There were no significant differences in TNF-alpha gene expression in strains expressing cagA versus those not expressing this gene, and no significant differences among strains with different vacA alleles.

CONCLUSIONS: TNF-alpha gene expression in the gastric mucosa of H. pylori-infected patients appears to be independent of H. pylori cagA/vacA genotype.