CD19 and acute lymphoblastic leukemia: In the setting of hematological malignancies, the first bispecific T cell engager (BiTE) produced was blinatumomab, directed against CD3 on T cells and CD19 on blast cells, currently approved for the treatment of patients with relapsed/refractory B cell-precursor acute lymphoblastic leukemia (B-ALL) or patients with B-ALL with hematological complete remission but persistent minimal residual disease [94].