This is a single arm study to evaluate the efficacy and safety of CD19 and CD22 targeted prime CAR-T cells therapy for patients with relapsed/refractory B -ALL
Signed written informed consent
Failed to standard chemotherapy regimens;
Relapse after complete remission, high-risk and / or refractory patients ;
Relapse after hematopoietic stem cell transplantation;
Previous history of other malignancy;
Presence of uncontrolled active infection;
Evidence of disorder that need the treatment by glucocorticoids;
Active or chronic GVHD