CD19 and acute lymphoblastic leukemia: In the last decade, however, the advent of targeted immunotherapies, e.g., the bispecific antibody blinatumomab (anti-CD19/anti-CD3), the antibody-drug conjugate inotuzumab ozogamicin (anti-CD22) and chimeric antigen receptor (CAR) T-cell therapy (herein referred to as CAR-T for brevity) has provided novel tools to achieve responses in patients with resistant leukaemia and dramatically augmented treatment options for R/R BCP-ALL (7).