Prognostic impact of subepithelial <i>Helicobacter pylori</i> infection on clinical outcomes in patients with dyspepsia

Several in vivo and in vitro studies have shown that Helicobacter pylori can invade epithelial cells and the lamina propria, potentially leading to underdiagnosis due to its subepithelial location. This retrospective study investigated H. pylori infection patterns and their impact on clinical improvement. Gastric tissue biopsies from 346 patients (August to December 2021) were studied using four commercially available immunohistochemical antibodies (TMDU, BioGenex, Cell Marque, and DAKO). The bacteria were graded based on their surface epithelial and subepithelial locations and then combined to establish an overall pattern. BioGenex, the antibody with the highest diagnostic performance due to its superior detection of surface and subepithelial cases, was selected as the gold standard for determining study outcomes. The isolated subepithelial H. pylori pattern was found to be an independent unfavorable prognostic feature. Patients with this pattern had the worst clinical outcomes compared to groups with isolated surface epithelial or other mixed patterns, which did not significantly differ. Subepithelial H. pylori should be included in pathological reports alongside the updated Sydney System. Further research should explore whether its eradication could improve treatment outcomes.