In the case of KymriahTM, which was suitable for patients with relapsed disease and/or refractory to conventional treatments, some common limitations to its use (insufficient white blood cells quality or count to produce the autologous product) led to the demand for allogeneic CD19-CAR-T cells for relapsed and/or refractory B-cell acute lymphoblastic leukaemia (ALL) under HE. This evidence concerns the gene CD19 and acute lymphoblastic leukemia.