CD19 and acute lymphoblastic leukemia: CD19 expression in ALL is of clinical importance due to the efficacy of anti-CD19 therapies such as blinatumomab or CAR-T cells.23,24 According to our results, daunorubicin, vincristine and prednisolone can induce down-modulation of CD19, which is partly consistent with data published by Van der Sluijs-Gelling et al. showing that CD19 is down-modulated after exposure to prednisolone, dexamethasone, vincristine or asparaginase.10 These changes may have implications for the treatment of children with resistant or relapsed ALL who receive blinatumomab or anti-CD19 CAR-T therapy.