Perforin and granzyme B of cytotoxic T lymphocyte mediate apoptosis irrespective of Helicobacter pylori infection: possible act as a trigger of peptic ulcer formation.

BACKGROUND/AIMS: The perforin/granzyme and Fas/Fas ligand pathways are two known major pathways of cytotoxic T lymphocyte-mediated apoptosis. We designed a clinical study to examine whether cytotoxic T lymphocyte-mediated apoptosis associated with peptic ulcer formation may occur via either or both of these two pathways.

METHODOLOGY

Mucosal biopsy specimens were obtained endoscopically from the marginal zone of active stage gastric and duodenal ulcers in patients with or without Helicobacter pylori infection. RT-PCR, immunoblotting and immunohistochemistry were used to study the samples for the expression of apoptotic cells, perforin, granzyme B, Fas, Fas ligand and caspase 3.

RESULTS

Apoptotic cells (Tunnel positive cells) appeared in the marginal zone of gastric and duodenal ulcers with and without H. pylori infection. Perforin/granzyme B and caspase 3 were expressed consistently, however Fas ligand was not. Furthermore, the immunohistochemical findings demonstrated apoptotic changes of target cells caused by perforin/granzyme B.

CONCLUSIONS

These results suggest that the main pathway of cytotoxic T lymphocyte-mediated apoptosis in peptic ulcer formation is the perforin/granzyme pathway irrespective of H. pylori infection.