Mast cell involvement in gastritis with or without Helicobacter pylori infection

Background & Aims: Mast cells are initiators and regulators of inflammation, but their role in the human stomach remains unclear. Therefore, the extent and distribution of mast cell involvement in gastritis with or without Helicobacter pylori infection was investigated. Methods: Mapped biopsy specimens from 17 H. pylori-positive and 20 H. pylori-negative subjects were examined. Sections were assessed for infection and inflammation and stained with anti-human mast cell tryptase to count mucosal and epithelial mast cells. Density of mast cells in different gastric compartments, their response to infection treatment, and their relationship with other inflammatory cells were evaluated. Mast cell degranulation was evaluated by electron microscopy. Results: Mast cell density was significantly greater in the mucosa with gastritis, with or without H. pylori infection, than in the mucosa of noninfected normal subjects. In the antrum, density was much greater in H. pylori-infected peptic ulcer subjects than in the other gastritis groups. It also correlated significantly with the intensity of inflammation. Mast cell degranulation was demonstrated by electron microscopy in H. pylori-infected mucosa. Mast cell density in ulcer patients decreased significantly after cure of H. pylori infection. Conclusions: Mast cells may be important effector cells in the pathogenesis of gastritis, especially in H. pylori-associated peptic ulcer.