We then used primary patient leukemia, UPN02, UPN02 CD19-KO, and two post-CD19CAR T-cell escape relapsed BM samples, rUPN21-R and rUPN22-R, as targets and observed that CD19/20/22CAR T-cells induced significantly higher lysis (Fig. 4d) and produced significantly higher levels of the TH1 cytokines TNF-α (Fig. 4e) and IFN-γ (Fig. 4f). Here, CD19 is linked to leukemia.