Variations in plasmacytoid dendritic cell (PDC) and myeloid dendritic cell (MDC) levels in HIV-infected subjects on and off antiretroviral therapy.

Plasmacytoid and myeloid dendritic cells are reduced in AIDS patients. The number of these circulating cells was assessed cross-sectionally and longitudinally in 27 uninfected and 72 HIV-infected subjects on and off antiretroviral therapy. The plasmacytoid dendritic cell numbers were significantly reduced in the HIV-infected subjects compared to controls (p < 0.001). This reduction correlated directly with CD4+ cell counts (p < 0.001) and inversely with viral load (p < 0.001). These associations were found to a lesser degree for the myeloid dendritic cells. Intra-assay variability of these dendritic cell counts was < 10%. Antiretroviral therapy significantly increased plasmacytoid dendritic cell (p < 0.001) and CD4+ cell (p = 0.05) counts at 8 months by 76.9% and 19%, respectively. The plasmacytoid dendritic cell levels responded more readily to viral load increases and decreases than CD4+ cells. Circulating plasmacytoid dendritic cells may provide important additional information about immune function in HIV-infected subjects receiving or not receiving antiretroviral therapy.