This is a single-arm, open-label, dose-escalation phase I clinical study to explore the safety, tolerability and pharmacokinetic characteristics of Human CD19-CD22 Targeted T Cells Injection. To preliminary observe the effect of Human CD19-CD22 Targeted T Cells Injection in relapsed/refractory B-cell acute lymphoblastic leukemia, and to explore the clinically applicable dose and reinfusion regimen for phase II.~Participants with relapsed/refractory B-cell Acute Lymphoblastic Leukemia can participate if all eligibility criteria are met. Tests required to determine eligibility include disease assessments, a physical exam, Electrocardiograph, Computedtomography （CT）/ Magnetic Resonance Imaging(MRI) / Positron Emission Tomography（PET）, and blood draws. Participants receive chemotherapy prior to the infusion of CD19-CD22 CAR+ T cells. After the infusion, participants will be followed for side effects and effect of CD19-CD22 CAR+ T cells. Study procedures may be performed while hospitalized.
To evaluate the safety and tolerability of Human CD19-CD22 Targeted T Cells Injection for the treatment of Relapsed/Refractory B-cell Acute Lymphoblastic Leukemia. Patients will be given a conditioning chemotherapy regimen of fludarabine and cyclophosphamide followed by a single infusion of CD19-CD22 CAR+ T cells.