Histopathological features of gastritis before and after treatment for Helicobacter pylori.

AIM To assess five main histological features of gastritis in gastric mucosa colonized with Helicobacter pylori before and after the treatment. METHODS Histologic assessment of H. pylori-associated gastritis was performed according to the Sydney classification before and after the treatment in 97 patients. Two additional parameters - the presence of lymphocytic aggregates and coccoid forms of bacteria - were also analyzed. Helical and coccoid forms of H. pylori were detected by immunohistochemistry in biopsies after the treatment. RESULTS Whereas acute epithelial damage was quickly repaired, some of the local responses to bacteria, e.g., lymphoid aggregates and intestinal metaplasia, persisted after treatment. Higher H. pylori and cocci density was found before and after treatment in patients with intestinal metaplasia (p=0.020). Correlation between H. pylori and mucosal atrophy was found only after treatment (p=0.009). Immunohistochemical staining was more sensitive in detecting of H. pylori than Giemsa staining (p=0.007) in cases where, using only Giemsa staining, it was not possible to distinguish coccoid forms of H. pylori from other cocci. CONCLUSION After treatment, H. pylori-associated gastritis showed reduction of acute and chronic inflammation, but lymphoid aggregates and intestinal metaplasia persisted. Immunohistochemistry of different forms of H. pylori may be a valuable technique in monitoring the success of the treatment.