Xu et al. have established a CRISPR/Cas9-mediated CCR5 (the main co-receptor of HIV) ablating system in long-term HSCs, which was purposed to inhibit HIV infection in mice.78 In a recent clinical trial (ClinicalTrials.gov: NCT03164135), allogenic CCR5-edited HSCs were transplanted to treat a single patient with HIV and related acute lymphoblastic leukemia. This evidence concerns the gene CCR5 and acute lymphoblastic leukemia.