Background: Previous studies suggest that Helicobacter pylori (H. pylori) induces apoptosis and compensatory hyperproliferation in gastric epithelial cells possibly explaining the carcinogenic capacity of the bacteria. The aim of this study was to measure the effect of H. pylori on apoptosis of gastric lymphoid cells in view of the development of gastric lymphoma.
Methods: 16 H. pylori-positive and 19 H. pylori-negative individuals were enrolled. Single cell suspensions were prepared from antral biopsies and apoptosis was measured by staining with the TUNEL-assay and the fluorochrome Hoechst 33342. Lymphocyte subsets were simultaneously identified by immunocytochemistry.
Results: The apoptotic index of all gastric mucosal cells was significantly higher in H. pylori-positive mucosa compared to negative controls. Additionally, H. pylori-infected patients showed a significant increase in apoptosis of mucosal B-lymphocytes. Apoptosis of T cells and plasma cells was unaffected by H. pylori.
Conclusion: H. pylori induces apoptosis in mucosal B cells which might be important in the development of gastritis and possibly B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT).