The investigator team involved in this trial has recently reported the first such case of CCR5 delta32/delta32 CB transplantation in a patient with HIV infection, showing a reduction of the patient's latent viral reservoir and, upon achievement of full CB chimerism, resistance of his CD4 T-lymphocytes to infection by HIV. This proof of concept led the Spanish National Transplant Organization (ONT) to generate an inventory of over 150 CCR5 Δ32/Δ32 CB units readily available for transplant.