Monocyte phenotype and extracellular vesicles in HIV-1, HIV-2, and HIV-1/2 dual infection

Objective:AIDS-defining illness develops at higher CD4+ T-cell counts in individuals infected with HIV-2 compared with HIV-1-infected, which suggests that the two types of HIV may have different effects on other compartments of the immune system. We here investigate monocyte phenotype, activation and macrophage-derived extracellular vesicles in individuals with different HIV types.Design:Cross-sectional.Methods:ART-naive HIV-1 (n = 83), HIV-2 (n = 63), and HIV-1/2 dually positive (n = 27) participants were recruited in Bissau, Guinea-Bissau, together with HIV-negative controls (n = 26). Peripheral blood mononuclear cells (PBMCs) were isolated and analyzed by flow cytometry for monocyte phenotype and activation, and plasma was analyzed for extracellular vesicle forms of CD163 and CD206.Results:Compared with HIV-negative controls, all groups of HIV-positive participants had a skewed monocyte phenotype with a higher proportion of intermediate monocytes, increased CD163 expression and elevated serum levels of the inflammatory biomarkers soluble (s)CD163 and sCD206. HIV-2-positive participants had lower CD163 monocyte expression than HIV-1-positive participants, regardless of HIV RNA or CD4+ cell count. Levels of sCD206 extracellular vesicles were increased in all HIV groups, and higher in HIV-1 compared with HIV-2-positive participants.Conclusion:The monocyte phenotype of HIV-2-positive participants deviated less from healthy controls than did HIV-1 participants. HIV-2-positive participants also had a lower concentration of extracellular CD206 vesicles compared with HIV-1-positive participants. This does not explain the difference in AIDS development.