CCR6 and HIV infectious disease: Within mucosal CD4 T-cell subsets, memory CCR6+ Th17 cells become depleted very early after acute SIV/HIV infection which results in GALT dysfunction (7, –, 10) since these cells play a crucial role in maintaining of gut mucosal immunity due to the secretion of interleukin-17 (IL-17) (5, 11, 12).