Effects of Helicobacter pylori infection on T cell activation markers and regulatory T cells in people with and without HIV infection in Central Ethiopia

Background: Helicobacter pylori (H. pylori) is known to modulate host immunity and sustain chronic inflammation, yet most data come from HIV-negative populations. In people living with HIV, whose T cell compartments are already dysregulated, the way H. pylori shapes peripheral T cell phenotypes, and how those profiles change after eradication therapy, is still unclear. Because both infections are common in Central Ethiopia, we examined peripheral T cell phenotypes in adults with and without HIV according to H. pylori status and assessed the immunologic effects of antibiotic eradication. Materials and Methods We conducted a prospective study in people with and without HIV infection from Ethiopia. H. pylori status was determined by stool-antigen testing; a subset received standard triple therapy and was followed for 12 months. Multiparameter flow cytometry quantified T cell activation, proliferation, exhaustion, and regulatory T cells (T _regs ) at baseline and after therapy. Results T cell analyses showed that participants with HIV had consistently higher proliferation (Ki67), exhaustion (PD-1, TIM3), and Th17 (CCR6⁺CD161⁺) markers than those without HIV. H. pylori -positive individuals exhibited higher T _reg levels irrespective of HIV status (HIV-negative: median 2% vs 1.08%, p < 0.0001; HIV-positive: median 2.9% vs 1.62%, p = 0.009). Eradication therapy led to a significant reduction in T _regs in both HIV-positive (SD 1.98%, p = 0.014) and HIV-negative (SD 1.5%, p = 0.023) groups. Conclusions H. pylori infection is associated with specific alterations in T cell profiles, in both HIV negative and positive populations. Eradication therapy, irrespective of success, reduces T _regs and partially restores T cell function, offering insight into potential therapeutic strategies for managing immune dysregulation in co-infected populations. Trial registration Not applicable. This study was not registered in a clinical trial registry, as there was no focus on investigational treatment. The aspects of the study reported here were observational in character. Ethical approval was obtained from both Ethiopian and German ethic committees. The study adhered to the Declaration of Helsinki and ICHGCP guidelines.