Schematic representation of the changes in blood DC numbers (blue line, both pDCs and mDCs) over time compared with HIV plasma viral load (dotted red line) during the acute (light blue background) and chronic (red background) phases of infection. The flowchart below the graph illustrates cellular and molecular events that may affect DC dynamics and their consequences on HIV disease. Activation of DCs during acute infection leads to their migration to lymphoid tissues, resulting in the reduction of circulating DCs. HIV-mediated cytopathic effect may contribute to DC depletion. Activated DCs are hyperresponsive to further stimulation due to overexpression of Toll-like receptor 7 (TLR7) and interferon regulatory factor 7 (IRF7). Chronic activation of DCs supports pathogenic T-cell activation and chronic inflammation.