The absence of bystander toxicities was confirmed by inoculating engrafted mice with the CD33+ MOLM-14 AML cell line: CD33.CAR-T cells were able to achieve tumor control in mice engrafted with either CD33-KO – or control HSCs, but caused off-leukemia toxicities only in the latter scenario (99). The gene discussed is CD33; the disease is acute myeloid leukemia.