In another paediatric study46, CD4+ and CD8+ T cells transfected with an anti-CD19 CAR construct containing a 4-1BB co-stimulatory domain using a lentiviral vector were administered to 45 children and young adults with pre-B cell ALL; 93% of the patients achieved MRD-negative remission by day 21. The gene discussed is CD19; the disease is acute lymphoblastic leukemia.