Higher circulating intermediate monocytes are associated with cognitive function in women with HIV.

Background Identifying a quantitative biomarker of neuropsychiatric dysfunction in people with HIV (PWH) remains a significant challenge in the neuroHIV field. The strongest evidence to date implicates the role of monocytes in central nervous system (CNS) dysfunction in HIV, yet no study has examined monocyte subsets in blood as a correlate and/or predictor of neuropsychiatric function in virally suppressed PWH. Methods In two independent cohorts of virologically suppressed women with HIV (vsWWH; n=25 and n=18), whole blood samples were obtained either in conjunction with neuropsychiatric assessments (neuropsychological [NP] test battery, self-report depression and stress-related symptom questionnaires) or one year prior to assessments. Immune cell subsets were assessed by flow cytometry. Results A higher proportion of intermediate monocytes (CD14+CD16+) was associated with lower global NP function when assessing monocytes concurrently and approximately one year before (predictive) NP testing. The same pattern was seen for executive function (mental flexibility) and processing speed. Conversely, there were no associations with monocyte subsets and depression or stress-related symptoms. Additionally, we found that a higher proportion of classical monocytes was associated with better cognition. Conclusion Although it is widely accepted that lentiviral infection of the CNS targets cells of monocyte-macrophage-microglial lineage, is associated with an increase in intermediate monocytes in the blood and monocyte migration into brain, the percentage of intermediate monocytes in blood of vsWWH has not been associated with neuropsychiatric outcomes. Our findings provide evidence for a new, easily measured blood-based cognitive biomarker in vsWWH. Funding R01-MH113512, R01-MH113512-S, P30-AI094189, R01-MH112391, R01-AI127142, R00-DA044838, U01-AI35004, and P30-MH075673.