CRISPR-Cas9-mediated knockout of TCRα/β and B2M in combination with lentiviral delivery of an anti-CD19 CAR into allogeneic T cells resulted in universal CAR T cells (UCART019) that are clinically tested in relapsed or refractory CD19+ leukemia and lymphoma patients (NCT03166878). This evidence concerns the gene B2M and leukemia.