CD19 and acute lymphoblastic leukemia: Our previous findings indicated that CD19‐targeting effector cells induce CD19 antigen depletion on B‐ALL target cells, which undermines the survival of target cells via disruption of the CD19/AKT/MYC axis.[36] We found that the expression of both the PI3K/AKT pathway and MYC were compromised in SEM cells as a result of CD19‐293‐EV‐mediated CD19 depletion.