Abstract

BACKGROUND:: Chronic inflammation and immune activation occur in both HIV infection and normal ageing and are associated with inflammatory disease. However, the degree to which HIV influences age-related innate immune changes, and the biomarkers which best reflect them, remains unclear. METHODS AND RESULTS:: We measured established innate immune ageing biomarkers in 309 individuals including 88 virologically-suppressed (VS) and 52 viremic (viral load </= and >50 copies/ml respectively) HIV+ individuals. Levels of soluble (ie. CXCL10, soluble CD163, neopterin) and cellular (ie. proportions of inflammatory CD16+ monocytes) biomarkers of monocyte activation were increased in HIV+ individuals and were only partially ameliorated by viral suppression. Viremic and VS HIV+ individuals show levels of age-related monocyte activation biomarkers that are similar to uninfected controls aged 12 and 4 years older respectively. Viremic HIV infection was associated with an accelerated rate of change of some monocyte activation markers (eg. neopterin) with age, whilst in VS individuals, subsequent age-related changes occurred at a similar rate as in controls, albeit at a higher absolute level. We further identified CXCL10 as a robust soluble biomarker of monocyte activation, highlighting the potential utility of this chemokine as a prognostic marker. IMPLICATIONS:: These findings may partially explain the increased prevalence of inflammatory, age-related diseases in HIV+ individuals and potentially indicate the pathological mechanisms underlying these diseases which persist despite viral suppression.

Supported by National Health and Medical Research Council of Australia (Project Grant 1048536).

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