Senl-h19 CAR-T Cell Injection in the Treatment of Patients With Relapsed or Refractory Acute Lymphoblastic Leukemia

Inclusion Criteria: * 1\. Sign the informed consent and be willing and able to comply with the visit, treatment protocol, laboratory examination, and other requirements of the study as specified in the study procedure sheet; 2. A definite diagnosis of relapsed and refractory acute B-lymphoblastic leukemia meets one of the following criteria: a) Mouse CAR-T treatment fails or relapses; B) Unable to bridge the graft for any reason; 3. Eastern Cooperative Oncology Group (ECOG) score ≤2; 4. Age ≥2 years old, male or female 5. CD19 positive tumor cells were detected by immunohistochemistry or flow cytometry; 6. Expected survival longer than 3 months; 7. The collection time of peripheral blood mononuclear immune cells must be at least 2 weeks from the last radiotherapy or systematic treatment of patients; Exclusion Criteria: * 1\. Severe cardiac insufficiency; 2. Have a history of severe lung impairment; 3. Complicated with other advanced malignant tumors; 4. Complicated with severe or persistent infection that cannot be effectively controlled; 5. Complicated with severe autoimmune diseases or congenital immune deficiency; 6. Active hepatitis (HBVDNA or HCVRNA positive); Human immunodeficiency virus (HIV) infection or syphilis infection; 8. Have a history of severe allergy to biological products (including antibiotics); 9. The female patient is pregnant and lactating, or has a pregnancy plan within 12 months; 10. Conditions that the investigator believes may increase the risk to the subject or interfere with the outcome of the study.