Helicobacter pylori causes hyperproliferation of the gastric epithelium: pre- and post-eradication indices of proliferating cell nuclear antigen.

OBJECTIVE: To assess the effect of Helicobacter pylori (HP) eradication on the proliferation of the gastric epithelium by the expression of the proliferating cell nuclear antigen (PCNA).
METHODS: Alcohol-fixed gastric biopsies taken before and after treatment for HP were immunostained with the PC-10 anti-PCNA monoclonal antibody and the labeling index was determined with an image analysis system.
RESULTS: The mean PCNA-labeling index (LI) of 16 patients who remained HP positive did not change significantly (18.95 +/- 1.71 on first visit vs. 17.96 +/- 1.91 on second visit, mean +/- SEM). The mean PCNA LI of 31 patients who cleared HP was reduced significantly (19.95 +/- 1.77 on first visit vs. 14.13 +/- 1.29 on second visit, p < 0.001). Patients who were positive for HP at both first and second visit showed a significantly higher PCNA LI than normal control biopsies (13.05 +/- 1.70) (p < 0.05).
CONCLUSIONS: These results indicate that the gastric mucosa infected with HP is in a state of hyperproliferation. Patients who cleared HP showed a significant histopathological improvement, reflected in the reduction in number of polymorphonuclear and mononuclear cell infiltrates, and a reduction in the amount of superficial mucosa damage. Prolonged hyperproliferation of the gastric epithelium exerted by HP infection could be a major factor for human gastric carcinogenesis.