CCR5 and HIV-1 infection: The discovery of CCR5 and CXCR4 as critical coreceptors for HIV-1 entry [1], [2], [4], coupled with the observation that patients heterozygous for CCR5Δ32 have a delayed disease progression [58], indicated that pharmacological blockade of the gp120-CCR5 interaction could be an effective strategy for inhibiting HIV-1 infection.