CD19 and non-Hodgkin lymphoma: Many of the first successful antibodies target single TAAs for the treatment of blood cancers, including CD19 for B-acute lymphoblastic leukemia (B-ALL), CD20 for Non-Hodgkin’s Lymphoma (NHL), and BCMA for multiple myeloma (MM), all of which are expressed exclusively in the hematopoietic system (1–3).