Helicobacter pylori Coinfection Is Associated With Decreased Markers of Immune Activation in ART-Naive HIV-Positive and in HIV-Negative Individuals in Ghana

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 HIVpositive 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 (HLADR+ 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 findingmight, in part, explain the observed association of H. pylori infection with favorable parameters of HIV disease progression. Clinical Trials Registration. Clinicaltrials.gov NCT01897909.
An article published by Oxford University Press and available at DOI: 10.1093/cid/civ577
HIV/AIDS;, Helicobacter pylori;, immune activation;, sub-Saharan Africa.
Oxford University Press CID 2015:61 (15 November) • 1615