T-cells fighting B-cell lymphoproliferative malignancies: the emerging field of CD19 CAR T-cell therapy

CAR T-cells are autologous T-cells transduced with a chimeric antigen receptor (CAR). The CAR contains an antigen recognition part (originating from an antibody), a T-cell receptor transmembrane and cytoplasmic signalling part, and one or more co-stimulatory domains. While CAR T-cells can be directed against any tumour target, most experience thus far has been obtained with targeting of the B-cell antigen CD19 that is expressed by B-cell acute lymphocytic leukaemia, chronic lymphocytic leukaemia and other B-cell lymphomas. The first clinical results are promising, although there are profound differences in response between patients with different haematological malignancies. Treatment-related side effects have been observed that require specific management. This review will explain the mechanism of action, summarise the experience to date and point out future directions for this hopeful new addition to the therapeutic armamentarium in the treatment of lymphoproliferative B-cell malignancies.