CCR5 and HIV infectious disease: Despite the urgent need for a cure for HIV infection, the risks associated with chemotherapy and radiation, and the relatively low frequency of ccr5∆32 homozygous individuals, makes it unlikely that allogeneic HSC transplants using cells from ccr5∆32 homozygous donors will become a widespread treatment option, and has prompted attempts to mimic the genetic knockout of CCR5 that was achieved in the Berlin patient.