Safety and Efficacy of Dual Specificity CD19 and CD22 CAR-T Cell Immunotherapy in R/R Acute B Lymphoblastic Leukemia

Inclusion Criteria: 1. Written informed consent could be acquired; 2. Diagnosed with relapse/refractory acute lymphoblastic leukemia; 3. Relapse was defined as recurrence of blast cell(more than 5%) in peripheral blood or in bone marrow or extramedullary involvement; 4. Refractory was defined as failed to achieve complete remission after two courses of induction therapy; 5. CD19/CD22 postive leukemia cell was confirmed by flow cytometry or immunohistochemistry within 90 days since enrollment in this trial; 6. Karnofsky score ≥70; 7. Results of pregnant test should be negative, and agree to conception control during treatment and 6 months after CAR-T infusion. 8. Adequate organ function: EF≥50%; normal ECG; CCR ≥ 50ml/min or Cr \< 2.0mg/dL or \< 2 times upper limitation of normal; ALT and AST\<5 times upper limitation of normal; Serum bilirubin ≤ 3.0mg/dL; DLCO or FEV1 \> 45% of predict value; 9. At least 2 weeks intervals since the last chemotherapy; 10. At least 2 weeks intervals since the last anti-GVHD therapy if patients have ever ; Exclusion Criteria: 1. Patients diagnosed with acute promyelocytic leukemia:t(15;17)(q22;q12); 2. Women in pregnancy and lactation; 3. Uncontrolled infection, Active HBV or HCV infection, HIV positive or any other deadly bacterial/virual diseases; 4. Long term use of systemic corticosteroids(5mg per day for 2 weeks); 5. Any other uncontrolled life-threaten diseases; 6. Patients with history of anaphylaxis to any drugs; 7. With central nervous system (CNS) involvement; 8. Patients with GVHD after allo-HSCT who needed immunosuppressive agents ; 9. Patients with acute autoimmune diseases such as psoriasis or rheumatoid arthritis; 10. Other conditions that principle investigator considered may increase the risk of the patients or interference the results.