PDC and HIV infectious disease: Consequently, frequencies of peripheral pDC decline as HIV infection progresses,18, 19, 20 and this loss may not be reversed with the administration of ART.21, 22 Loss of pDC is thought to be a result of both the apoptosis of pDC following their direct infection by HIV23 and the redistribution of pDC from the peripheral circulation to secondary lymphoid organs in response to HIV-induced upregulation of the migration marker CCR7.24, 25