Altered Monocyte and Endothelial Cell Adhesion Molecule Expression Is Linked to Vascular Inflammation in Human Immunodeficiency Virus Infection

BACKGROUND. Human immunodeficiency virus (HIV)-infected individuals have increased risk for vascular thrombosis, potentially driven by interactions between activated leukocytes and the endothelium. METHODS. Monocyte subsets (CD14(+)CD16(−), CD14(+)CD16(+), CD14(Dim)CD16(+)) from HIV negative (HIV(−)) and antiretroviral therapy-treated HIV positive (HIV(+)) participants (N = 19 and 49) were analyzed by flow cytometry for adhesion molecule expression (lymphocyte function-associated antigen 1 [LFA-1], macrophage-1 antigen [Mac-1], CD11c/CD18, very late antigen [VLA]-4) and the fractalkine receptor (CX3CR1); these receptors recognize ligands (intercellular adhesion molecules [ICAMs], vascular cell adhesion molecule [VCAM]-1, fractalkine) on activated endothelial cells (ECs) and promote vascular migration. Plasma markers of monocyte (soluble [s]CD14, sCD163) and EC (VCAM-1, ICAM-1,2, fractalkine) activation and systemic (tumor necrosis factor receptor [TNFR-I], TNFR-II) and vascular (lipoprotein-associated phospholipase A(2) [Lp-PLA(2)]) inflammation were measured by enzyme-linked immunosorbent assay. RESULTS. Proportions of CD16(+) monocyte subsets were increased in HIV(+) participants. Among all monocyte subsets, levels of LFA-1 were increased and CX3CR1 levels were decreased in HIV(+) participants (P < .01). Levels of sCD163, sCD14, fractalkine, ICAM-1, VCAM-1, TNFR-II, and Lp-PLA(2) were also increased in HIV(+) participants (P < .05), and levels of sCD14, TNFR-I, and TNFR-II were directly related to ICAM-1 and VCAM-1 levels in HIV(+) participants. Expression of CX3CR1 on monocyte subsets was inversely related to plasma Lp-PLA(2) (P < .05 for all). CONCLUSIONS. Increased proportions of CD16(+) monocytes, cells with altered adhesion molecule expression, combined with elevated levels of their ligands, may promote vascular inflammation in HIV infection.