Gut-Homing CD4⁺ T Cells Are Associated with the Activity of Gastritis in HIV-Infected Adults

Previous studies have shown that HIV-infected individuals were less susceptible to chronic gastritis and Helicobacter pylori infection. Th1 and Th17 cells are important components of the immune response to H. pylori in adults. We investigated the relative importance of Th1 versus Th17 responses for mucosal inflammation and protection. We conducted a prospective cross-sectional study to evaluate the relationship among the peripheral blood gut-homing CD4⁺ T cell subset, the severity of chronic H. pylori gastritis, and H. pylori amount in the gastric mucosa. Biopsy specimens were obtained at the time of gastroendoscopy, which was used for classification of histological gastritis by updated-Sydney system. Peripheral blood mononuclear cells were collected at the same point to determine the frequency of peripheral blood gut homing CD4⁺ T cells (CCR9⁺integrin β₇⁺) and CD4⁺ memory T cells subsets by flow cytometry. H. pylori amount in the gastric mucosa was measured using 16S ribosomal RNA gene amplicon sequencing. Peripheral blood gut-homing CD4⁺ T cells were significantly higher in individuals with histological gastritis compared with those without chronic gastritis (median 16.8 cells/μL vs. 9.7 cells/μL; p = .0307). In particular, there were significant differences in gut-homing Th1 (median 1.3 cells/μL vs. 0.5 cells/μL; p = .0061) and nonconventional Th1 (median 0.4 cells/μL vs. 0.2 cells/μL; p = .0196). In addition, there was a significant positive correlation between H. pylori amount in the gastric mucosa measured using 16S ribosomal RNA gene amplicon sequencing and gut-homing Th1 subsets. Our findings suggested that gut Th1 may play a key role in the development of chronic gastritis in HIV-infected individuals.