HIV infection induces age-related changes to monocytes and innate immune activation in young men that persist despite combination antiretroviral therapy

Objectives: To compare the impact of HIV infection and healthy ageing on monocyte phenotype and function and determine whether age-related changes induced by HIV are reversed in antiretroviral treated individuals. Design: A cross sectional study of monocyte ageing markers in viremic and virologically suppressed HIV-positive males aged 45 years or less and age-matched and elderly (65 years) HIV-uninfected individuals. Methods: Age-related changes to monocyte phenotype and function were measured in whole blood assays ex vivo on both CD14CD16 (CD14) and CD14CD16 (CD16) subsets. Plasma markers relevant to innate immune activation were measured by ELISA. Results: Monocytes from young viremic HIV-positive males resemble those from elderly controls, and show increased expression of CD11b (P<0.0001 on CD14 and CD16subsets) and decreased expression of CD62L and CD115 (P=0.04 and 0.001, respectively, on CD14 monocytes) when compared with young uninfected controls. These changes were also present in young virologically suppressed HIV-positive males. Innate immune activation markers neopterin, soluble CD163 and CXCL10 were elevated in both young viremic (P<0.0001 for all) and virologically suppressed (P=0.0005, 0.003 and 0.002, respectively) HIV-positive males with levels in suppressed individuals resembling those observed in elderly controls. Like the elderly, CD14 monocytes from young HIV-positive males exhibited impaired phagocytic function (P=0.007) and telomere-shortening (P=0.03) as compared with young uninfected controls. Conclusion: HIV infection induces changes to monocyte phenotype and function in young HIV-positive males that mimic those observed in elderly uninfected individuals, suggesting HIV may accelerate age-related changes to monocytes. Importantly, these defects persist in virologically suppressed HIV-positive individuals.