CD19 and neoplasm: To test the long-term effects of ITK deletion on CD19-CAR-T cells in vivo, we first used a CLL mouse model of NOD-PrkdcscidIl2rγnull (NPG) mice bearing MEC1 tumor cells (injected intraperitoneally) followed by infusion with ITK-KO or nt-KO CD19-CAR-T cells (Figure 5A).