Dual Target CAR-T Cells in B-cell Acute Lymphoblastic Leukemia

Inclusion Criteria: * Subjects must meet the following criteria to participate in this study: 1. 14-75 years old, no gender limit; 2. According to the 2020 World Health Organization (WHO) diagnostic criteria, it is diagnosed as relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL); 3. ECOG behavior status score is 0-2 points; 4. Expected survival time ≥ 3 months; 5. No contraindications to peripheral apheresis; 6. Flow cytometry confirms that the original cells express CD22; 7. Those who are tolerant to CD19 CAR-T cell therapy or those with low CD19 expression; 8. No serious heart, lung, liver or kidney disease; 9. Ability to understand and willing to sign the informed consent form for this trial. Exclusion Criteria: * Patients with any of the following cannot be included in this study: 1. The original cells expressing CD19 and CD22 are negative; 2. There is active infection; 3. Abnormal liver function ( glutamic-pyruvic transaminase\>1.5×ULN, glutamic oxalacetic transaminase\>2.5×ULN), abnormal renal function (serum creatinine\>1.5×ULN); 4. People with unstable angina or New York Heart Association class 3/4 congestive heart failure, multiple organ dysfunction; 5. HIV/AIDS patients; 6. Those who need long-term anticoagulation (warfarin or heparin), antiplatelet (aspirin, dose\>300mg/d; clopidogrel, dose\>75mg/d) treatment; 7. Those who received radiotherapy within 4 weeks before the start of the study (blood sampling); 8. Known or suspected drug abuse or alcohol dependence; 9. People with mental illness or other conditions cannot obtain informed consent, and cannot cooperate with the requirements for completing the experimental treatment and inspection procedures; 10. Those who have participated in other clinical trials within 30 days; 11. Pregnant or lactating women, male subjects (or their partners) or female subjects have a pregnancy plan during the study period to 6 months after the end of the test, and are unwilling to use a medically approved effective contraceptive measure during the test period (Such as intrauterine device or condom); 12. The investigator judged that it is not suitable to participate in this trial.