CCR5 and HIV infectious disease: With regard to HIV infection, there has been a great deal of interest in the potential role of CD16+ monocytes, particularly CD14++/CD16+ intermediate monocytes, in disease pathogenesis given that these populations (which co-express CCR5) [3] are permissive to HIV infection [4] and are capable of transferring HIV infection across the genital mucosal barrier [5] as well as into the central nervous system [6].