CD19 and B-cell acute lymphoblastic leukemia: The high rates of remission induced by the CAR T cells in relapsed/refractory CD19-expressing B cell malignancies have led to FDA approval of several anti-CD19 CAR T cell products for the treatment of both diffuse large B cell lymphoma (DLBCL) and B cell acute lymphoblastic leukemia (ALL) [1,2,3].