Background: Helicobacter pylori coinfection in human immunodeficiency virus (HIV) patients has been associated with higher CD4+ cell counts and lower HIV-1 viral loads, with the underlying mechanisms being unknown. The objective of this study was to investigate the impact of H. pylori infection on markers of T-cell activation in HIV-positive and HIV-negative individuals.
Methods: In a cross-sectional, observational study, HIV patients (n = 457) and HIV-negative blood donors (n = 79) presenting to an HIV clinic in Ghana were enrolled. Data on clinical and sociodemographic parameters, CD4+/CD8+ T-cell counts, and HIV-1 viral load were recorded. Helicobacter pylori status was tested using a stool antigen test. Cell surface and intracellular markers related to T-cell immune activation and turnover were quantified by flow cytometry and compared according to HIV and H. pylori status.
Results: Helicobacter pylori infection was associated with decreased markers of CD4+ T-cell activation (HLA-DR+CD38+CD4+; 22.55% vs 32.70%; P = .002), cell proliferation (Ki67; 15.10% vs 26.80%; P = .016), and immune exhaustion (PD-1; 32.45% vs 40.00%; P = .005) in 243 antiretroviral therapy (ART)-naive patients, but not in 214 patients on ART. In HIV-negative individuals, H. pylori infection was associated with decreased frequencies of activated CD4+ and CD8+ T cells (6.31% vs 10.40%; P = .014 and 18.70% vs 34.85%, P = .006, respectively).
Conclusions: Our findings suggest that H. pylori coinfection effectuates a systemic immune modulatory effect with decreased T-cell activation in HIV-positive, ART-naive patients but also in HIV-negative individuals. This finding might, in part, explain the observed association of H. pylori infection with favorable parameters of HIV disease progression.
Clinical trials registration: Clinicaltrials.gov NCT01897909.
Keywords: HIV/AIDS; Helicobacter pylori; immune activation; sub-Saharan Africa.
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