CD19 and B-cell chronic lymphocytic leukemia: Since 2010, numerous clinical trials have demonstrated the ability of CAR T cells directed against CD19 to promote clinical responses in acute lymphoblastic leukemia (ALL) (6–10), diffuse large B cell lymphoma (DLBCL) (11–13), chronic lymphocytic leukemia (CLL) (14, 15), and other B-cell non-Hodgkin lymphomas (16, 17) with remissions of up to 90% in some of these cases.