CD22 and acute lymphoblastic leukemia: A clinical trial involving 89 patients with ALL tested the safety and efficacy of the combined infusion of CD19 CAR-T and CD22 CAR-T cells and observed a disease-negative response rate of 96.0% and 1 case of relapse due to antigen-loss, further demonstrating the impact of targeting multiple tumor antigens in order to reduce antigen-loss relapse [79].