Depletion in blood CD11c-positive dendritic cells from HIV-infected patients.

OBJECTIVES: To quantify blood dendritic cells from HIV-positive patients and to study the expression of functional molecules, in relation to HIV viral load, CD4 cell counts and antiretroviral treatment. DESIGN AND METHODS: Three-colour flow cytometry analysis was used to quantify blood dendritic cells without previous isolation from whole blood and to study the expression of functional molecules (MHC class II, CD11c, CD83, CD86) by dendritic cells from 30 HIV-positive patients, 15 of whom were treated with combined antiretroviral therapy (viral loads from undetectable to 5.4 log copies/ml, CD4 cell counts 1-1895 cells/mm3) and 11 non-infected controls.
RESULTS: The median proportion of blood dendritic cells from HIV-positive patients was significantly decreased when the plasma viral load was above 200 copies/ml: 0.2% (0.1-1.1, n = 19) compared with 0.4% (0.2-0.8, n = 11) in patients with undetectable viral load whether they were treated or not, and to 0.4% (0.2-1.3, n = 11) in controls (P = 0.02). A major decrease of the CD11c positive dendritic cells was observed in all HIV-positive samples, with only 18% (mean; range: 0.3-80%, median 4.2%) compared with 44% (11-70%, median 42%) of control dendritic cells (P = 0.0006). In contrast, the proportion of dendritic cells expressing CD86, was slightly higher in HIV-positive patients than in controls (P = 0.03).
CONCLUSIONS: The decreased proportion of blood dendritic cells correlated with virus replication and the lack of dendritic cells expressing CD11c are the first evidence of strong dendritic cell alterations in HIV-positive patients. Although the proportion of blood dendritic cells are in the normal range in treated HIV-positive patients with undetectable viral load, the CD11c alterations persist indicating that antiretroviral therapy might only partly correct the alterations of the circulating dendritic cells.