The level (or frequency) of circulating monocyte subpopulations such as classical (CD14hiCD16?) and non-classical\n(CD14dimCD16+) monocytes varies during the course of HIV disease progression and antiretroviral therapy (ART).\nWe hypothesized that such variation and/or differences in the degree to which these cells expressed the\nimmunoregulatory enzyme, heme oxygenase-1 (HO-1), would be associated with CD4+ T cell recovery after the\ninitiation of ART. This hypothesis was tested in a cross-sectional study of four groups of HIV-infected subjects,\nincluding those who were seronegative, untreated virologic controllers [detectable viral load (VL) of <1000 copies/\nmL], untreated virologic non-controllers [VL > 10,000 copies/mL], and ART-mediated virologic controllers [VL < 75\ncopies/mL]. A longitudinal analysis of ART-treated subjects was also performed along with regression analysis to\ndetermine which biomarkers were associated with and/or predictive of CD4+ T cell recovery. Suppressive ART was\nassociated with increased levels of classical monocyte subpopulations (CD14hiCD16?) and decreased levels of\nnon-classical monocyte populations (CD14dimCD16+). Among peripheral blood mononuclear cells (PBMCs), HO-1\nwas found to be most highly up-regulated in CD14+ monocytes after ex vivo stimulation. Neither the levels of\nmonocyte subpopulations nor of HO-1 expression in CD14+ monocytes were significantly associated with the\ndegree of CD4+ T cell recovery. Monocyte subpopulations and HO-1 gene expression were, however, restored to\nnormal levels by suppressive ART. These results suggest that the level of circulating monocyte subpopulations and\ntheir expression of HO-1 have no evident relationship to CD4+ T cell recovery after the initiation of ART.
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