Pathogenic implications of interleukin-8 activity and bacterial phenotype in antral gastritis associated with Helicobacter pylori

OBJECTIVE: Helicobacter pylori (Hp) infection is characterized by an intense inflammatory infiltrate in the gastric mucosa, which is chemoattracted by different cytokines. Interleukin-8 (IL-8) seems to play an important role in the recruitment of circulating neutrophils, and modulation of IL-8 secretion seems to be a strain marker. This study was designed to examine IL-8 concentrations in the gastric mucosa and their relationship with H. pylori phenotype and histologic findings. METHODS: gastric biopsies were obtained from the antrum and corpus in 106 patients (69 Hp-positive and 37 Hp-negative). IL-8 levels in the gastric mucosa were analyzed by ELISA and Hp phenotype was determined with a western blot test. RESULTS: 75% of H. pylori strains were CagA+ and 54.2% were VacA+. The Houston classification was used for histologic findings. No association between gastric atrophy or intestinal metaplasia and Hp phenotype was found. The highest IL-8 levels were found in CagA+ infected gastric mucosa, but the difference with respect to infection by a VacA+ strain was not statistically significant. IL-8 levels were highest when neutrophils were the predominant cell in the gastric inflammatory infiltrate (p < 0.05). IL-8 levels were higher in patients with atrophic gastritis than in patients with nonatrophic gastritis (p<0.05). CONCLUSIONS: in patients with H. pylori infection, IL-8 levels are higher than in Hp-negative patients regardless of Hp phenotype. There is an association between IL-8 and a neutrophilic infiltrate. Perpetuation of a chronic infiltrate could lead to more severe lesions such as atrophic gastritis or intestinal metaplasia, as deduced from the IL-8 levels found in these types of lesion.