Phase I/II studies of JCAR014 (late-stage B-cell malignancies) and JCAR017 (pediatric ALL) have shown that pretreating patients with fludarabine and cyclophosphamide to remove lymphocytes before administering CD19-CAR-T cells can enhance the therapeutic effect of CAR-T cells (29). The gene discussed is CD19; the disease is acute lymphoblastic leukemia.