CD34 and acute lymphoblastic leukemia: To that end, the first clinical trial, using C-C chemokine receptor type 5 (CCR5) knockout CD34+ HSPCs edited by gRNAs with the chemical modifications described in Hendel et al. (2015a), has already been conducted in an HIV-positive patient with Acute Lymphoblastic Leukemia (Xu et al., 2019).