Objectives: To examine the background histology, interleukin-8 (IL-8) secretion, and expression of IL-8 mRNA and protein, using the gastric antral mucosa infected with Helicobacter pylori.
Methods: The antral biopsies were obtained from an area of endoscopically intact mucosa in 147 patients whose endoscopic diagnoses were normal (n = 41), duodenal ulcer (n = 58), gastric ulcer (n = 21), or gastritis (n = 27). Levels of IL-8 secreted in the organ cultures of mucosal biopsies were measured by an ELISA assay, and the expression of IL-8 mRNA and protein was analyzed in fresh biopsy tissues with RT-PCR and immunofluorescent microscopy, respectively.
Results: Significantly greater levels of IL-8 were secreted in patients with H. pylori infection, and its elevation was more prominent in duodenal ulcer patients than in those with gastric ulcer or endoscopically defined gastritis. There was an association among H. pylori density, IL-8 activity, and histological severity of activity and inflammation of gastritis in the Sydney system. Consistent with enhanced IL-8 activity in the organ cultures, IL-8 mRNA was detected in 16 of 23 fresh biopsy tissues studied in H. pylori-positive patients. In contrast, IL-8 transcript was detected in only one of 12 H. pylori-negative cases. Immunofluorescent microscopy showed localization of IL-8 protein in the gastric epithelial cells and lamina propria cells, primarily CD68+ macrophages in specimens with H. pylori infection.
Conclusions: This study indicates that a strong correlation exists between mucosal IL-8 activity and histological severity in H. pylori-associated antral gastritis. Further studies will be necessary to determine the mechanisms involved in elevated mucosal IL-8 activity in H. pylori infection.