Expansion of the non-classical monocyte pool predicts elevated mood disturbance in post-menopausal women with and without HIV infection

Abstract

Human Immunodeficiency Virus (HIV-1) infection is associated with expansion of the non-classical monocyte pool. These monocytes transmigrate across the blood-brain-barrier and induce proliferation of pro-inflammatory cytokines. Although this expansion has been linked to HIV-associated neurocognitive impairment, associations with psychological functioning are unclear. Flow cytometric analysis yielded the proportion of gated non-classical, intermediate and classical monocytes in 22 post-menopausal women (11 HIV+ and 11 HIV-negative) aged 55.77 years (SD = 6.32). A regression model tested variance in the proportion of non-classical monocytes accounted for by HIV status and scores on the Profile of Mood States questionnaire. Accounting for HIV status, mood disturbance accounted for 28% of the variance in non-classical monocytes, R2 = 0.275, F(2,21) = 3.69, p = 0.047. For every 1 unit increase in mood disturbance, the proportion of non-classical monocytes increased by nearly 10%, B = 0.096, SE = 0.04, t = 2.59 p = 0.018. However, HIV status did not predict variance in the proportion of mononuclear cells B = 1.18, SE = 2.37, t = 0.498, p > 0.05, suggesting expansion of the non-classical monocyte pool is associated with increasing levels of mood disturbance, independent of HIV infection. More work is needed to determine whether peripheral or neural-inflammation resulting from activation of non-classical monocytes potentially drives and/or may be driven by distress in HIV positive individuals.