CD19 and acute lymphoblastic leukemia: Tisagenlecleucel (tisa-cel), a second generation anti-CD19 CAR-T cell constructed with a CD3zeta signalling domain and 4-1BB co-stimulatory domain transduced into autologous patient T cells, was the first product approved by the FDA for the treatment of R/R B-ALL in patients up to 25 years of age.