CD14(low)CD16(high): A cytokine-producing monocyte subset which expands during human immunodeficiency virus infection

Infection with the human immunodeficiency virus HIV-1 is associated with the expansion of a CD14(low)CD16(high) monocyte subset in peripheral blood. This subset, which represents a minor subpopulation of monocytes in healthy individuals, increases during HIV infection and, in patients with BIDS, may represent up to 40% of the total circulating monocyte cell population. The CD14(low)CD16(high) circulating monocytes co-express MAX.1, p150,95 and HLA-DR which are typical of tissue macrophage markers. These cells also express higher levels of intracellular interleukin (IL)-1 alpha and tumor necrosis factor (TNF)-alpha than the CD14(high)CD16(low) monocyte population from the same patients. The CD14(low)CD16(high) cells also express low levels of CD35, CD11a and CD4 in common with normal monocytes. When cultured in vitro, monocytes from HIV-seropositive individuals differentiated within a few hours into an elongated fibroblastoid shape characteristic of migratory cells. Our results suggest that the expansion of the CD14(low)CD16(high) monocyte subset, which produce high amounts of TNF-alpha acid IL-1 alpha, may participate in the immune dysfunction observed during HIV infection.