Selective Expansion of Pro-inflammatory Chemokine CCL2-Loaded CD14+CD16+ Monocytes Subset in HIV-Infected Therapy Naïve Individuals

We have previously demonstrated the critical role of C-C chemokine CCL2 in HIV-1 pathogenesis, and circulating monocytes as the major source of CCL2. Since the functional aspect of monocyte subsets in context to CCL2 production is unclear, we investigated the frequency and production of CCL2 by circulating monocyte subsets in a cohort of HIV- therapy naive patients. A cohort of HIV-infected therapy naive patients (n = 9) and healthy controls (n = 6) were recruited for this study. To examine monocyte subset frequency and CCL2 production, we performed surface and intra-cellular staining of freshly isolated peripheral blood mononuclear cells (PBMC) and subjected to flow cytometry. A preferential expansion of CD14+CD16+ monocyte subset, coupled with increased intracellular production of CCL2 was observed in HIV-1 patients compared to healthy controls. Interestingly this phenotype was mostly restricted to CD14+CD16+ monocyte subsets. This study identifies pro-inflammatory CCL2 producing CD14+CD16+ monocyte subset that expands selectively in HIV-1 infection and could potentially participate in causing immuno-pathology.