CD19 and acute lymphoblastic leukemia: Fueled by the success of immunotherapeutic strategies in other malignant hematologic entities, e.g., the anti-CD20 antibody rituximab in Non-Hodgkin’s-lymphoma (NHL) or the CD19-specific chimeric antigen receptor (CAR)-T-cell therapies in acute lymphoblastic leukemia (ALL) and NHL, several efforts have been made to develop antibody-based or cellular immunotherapies for AML.