HELICOBACTER-PYLORI CAGA GENE AND EXPRESSION OF CYTOKINE MESSENGER-RNA IN GASTRIC-MUCOSA

Background & Aims: Helicobacter pylori strains possessing the cagA gen e are thought to be associated with gastroduodenal diseases. Furthermo re, some cytokines are considered to play a role in gastric mucosal in flammation. The aim of the study was to investigate the relationship b etween cagA gene and cytokine messenger RNA (mRNA) expression in gastr ic mucosa. Methods: In 160 patients, the cagA gene was detected using polymerase chain reaction, and interleukin (IL) 1 beta, IL-6, IL-7, IL -8, IL-10, and tumor necrosis factor (TNF) alpha mRNA were detected us ing reverse-transcription polymerase chain reaction. Results: Specimen s infected with CagA gene-positive strains (cagA-positive specimens) h ad significantly more severe infiltration of polymorphonuclear leukocy tes and mononuclear cells than those infected with cagA gen-negative s trains (cagA-negative specimens). Levels of expression of IL-6, IL-7, IL-8, IL-10, and TNF-alpha mRNA were significantly higher in H. pylori -positive than H. pylori-negative patients. Furthermore, the level of IL-8 mRNA expression was significantly higher in cagA-positive than ca gA-negative specimens. Conclusions: cagA-positive strains induce the e xpression of IL-8 mRNA, suggesting that IL-8 may play important roles in the pathogenesis of gastroduodenal diseases associated with H. pylo ri infection.