CD19 and precursor B-cell acute lymphoblastic leukemia: Interestingly, in another phase 1 clinical trial21 with a bispecific CAR capable of simultaneously recognizing CD22 and CD19 in adult patients with relapsed or refractory B-ALL and large B cell lymphoma, in contrast to our study, none of the relapses was associated with CD22 antigen loss or low expression, suggesting that potency toward the CD22 antigen was insufficient in this other dual targeting CAR construct.