Invasive chronic inflammatory monocyte phenotype in subjects with high HIV-1 viral load

Human immunodeficiency virus type 1 (HIV-1)-infected monocytes trafficking into the central nervous system are a risk factor for HIV-1-associated dementia. We performed global gene expression analysis on CD14+ monocytes isolated from HIV-1-infected individuals and controls to identify HIV-1-related changes in monocyte phenotype. Monocytes from subjects with high viral load (HVL) had a significant increase in monocytes expressing CD16, CCR5, and MCP-1. There was also an increase in sialoadhesin, a macrophage marker of chronic inflammation. Expression of proinflammatory cytokine genes IL-1, IL-6, and TNF-alpha was unchanged in individuals with HIV-1 compared to control CD14+ monocytes. Differential gene expression identified by DNA microarray analysis was confirmed with reverse transcription polymerase chain reaction (RT-PCR), while increased protein expression was characterized by immunofluorescence. We concluded that there is a circulating CD14+ macrophage hybrid phenotype in subjects with HVL.