CCR6 and HIV infectious disease: The CCR6+ CXCR3- CCR4- (double negative) cell subtype may be preserved during HIV infection in blood and lymph nodes, unlike the Th17 (CCR6+ CXCR3- CCR4+), Th1/Th17 (CCR6+ CXCR3+ CCR4-), and double-positive (CCR6+ CXCR3+ CCR4+) subtypes, which are more severely depleted and only partially restored under ART (60).