DLI with genetically retargeted T cells. An allogeneic stem cell donor (either matched sibling or matched unrelated donor [URD]) undergoes steady-state mononuclear cell apheresis to obtain T cells. After enrichment, the T cells are transduced with a retroviral vector that carries a gene that encodes the CD19 CAR. The CD19 CAR has an antibody-derived CD19 binding domain composed of ligand or tumor antigen binding domain derived from the variable regions of the heavy (V_H) and light chains (V_L) of an anti-CD19 antibody molecule fused to signaling domains that may be derived from the CD3 ζ chain, CD28, 4-1BB, or a combination thereof. A simplified representation of the native or endogenous TCR complex is also shown with the α and β subunits and components of CD3 (δ, ε, γ). After expansion in culture, the gene-modified T cells are transferred to the patient with a CD19⁺ B-cell malignancy. Following infusion, the gene-modified T cells expand and target the CD19⁺ B-cell malignancy.