LAUSR

OBJECTIVES Previous studies had shown that HIV-infected individuals were less susceptible to chronic gastritis and Helicobacter pylori (H. 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. METHODS 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, H. pylori amount in the gastric mucosa. Biopsy specimens was obtained at the time of gastroendoscopy, which was used for classification of histologic 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. RESULTS Peripheral blood gut-homing CD4+ T cells were significantly higher in individuals with histological gastritis compared to those without chronic gastritis (median 16.8 cells/μL vs. 9.7 cells/μL; p=0.0307; FIG. 2A). In particular, there were significant differences in gut-homing Th1 (median 1.3 cells/μL vs. 0.5 cells/μL; p=0.0061; FIG. 2B) and nonconventional Th1 (median 0.4 cells/μL vs. 0.2 cells/μL; p=0.0196; FIG. 2C). 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. CONCLUSIONS Our findings suggested that gut Th1 may play a key role in the development of chronic gastritis in HIV-infected individuals.