IL2 and leukemia: The significant specific cytotoxicity (Fig. 3b), high expression of CD107a (Fig. 3c), and IFN-γ release (Fig. 3d) were observed in FLT3L CAR-T cells co-cultured with both FLT3-ITD and FLT3-WT patient leukemia cells compared to that in VEC-T cells co-cultured with patient cells, while secretion of IL-2 showed no difference, similar to the results of cell lines (Fig. 3d).