In this single-center, open-label, single-arm, prospective clinical trial, a total of 20 recurrent or refractory CD19+ B cell acute lymphoblastic leukemia patients will be enrolled.After recruiting eligible patients,autologous peripheral blood mononuclear cells(PBMCs) will be purified from whole blood.The CD3+ T cells were subsequently selected and re-stimulated by anti-CD3 and anti-CD28 monoclonal antibodies.T cells will be transduced with lentiviral vector for the generation of the CD19 CART cell and administered by i.v. injection.The purpose of current study is to determine the safety and clinical efficacy of CD19 CAR T cells therapy in patients with recurrent or refractory CD19+ ALL.
