CD19 and acute lymphoblastic leukemia: To further evaluate the specific cytotoxicity of CAR19-NK-92 cells, we tested their activity against CD19-positive B cell lines, including Nalm-6 (derived from a patient with acute lymphoblastic leukemia), Raji, and Namalwa (both derived from patients with Burkitt lymphoma) as well as the CD19-negative cell line K562 (derived from a patient with chronic myelogenous leukemia) as negative control.