In a cohort of six pediatric patients with CD19 + blast > 99% relapsed/refractory B-ALL, CD19-targeting TRAC + CD52 KO CAR Ts yielded 4/6 CR/CRi, two of them in remission by the time of report at 3 and 12 months. This evidence concerns the gene CD19 and precursor B-cell acute lymphoblastic leukemia.