The Clinical Study of CD19 UCAR-T Cells in Patients With B-cell Acute Lymphoblastic Leukemia (B-ALL)

Inclusion Criteria:

* 1\. Subjects between 6 and 70 years of age, inclusive.
* 2\. Subjects diagnosed as relapsed or refractory B cell acute lymphocytic leukemia (B-ALL):

  1. Relapse as defined by 2nd or greater BM relapse or Any BM relapse after allogeneic SCT, naive lymphocytes in BM≥5%；
  2. refractory as defined by not achieving a CR after 2 rounds of standard chemotherapy.
* 3\. Life expectancy \> 12 weeks.
* 4\. ECOG score between 0 and 1.
* 5\. Liver, Renal, Heart and Lungs function defined as:

  1. Creatininec≤1.5 ULN;
  2. ALT/AST ≤2.5 ULN;
  3. Total Bilirubin≤1.5×ULN;
  4. Pulse oxygenation≥92%;
  5. Left Ventricular Shortening Fraction (LVSF)≥50%;
* 6\. Subjects could comprehend the clinical study and able to provide written consent at the time of consent or assent.

Exclusion Criteria:

* 1\. Pregnant or lactating women, or men or women with pregnancy plans within 6 months.
* 2\. Subjects with contagious disease，such as HIV, active HBV and HCV, and syphilis, etc.
* 3\. Subjects with mental or psychological illness who cannot be combined with treatment and efficacy evaluation.
* 4\. Subjects with severe autoimmune disease and long-term use of immunosuppressants.
* 5\. Subjects with active or uncontrollable infections requiring systemic treatment within 14 days prior to enrollment.
* 6\. Subjects with any unstable systemic disease including, but not limited to, active infection (except for local infection), unstable angina pectoris, cerebrovascular accident or transient cerebral ischemia (within 6 months prior to screening), myocardial infarction (within 6 months prior to screening), congestive heart failure (New York Heart Association \[NYHA\] classification ≥ III).
* 7\. subjects combined with dysfunction of vital organs such as lung, brain and kidney.
* 8\. subjects that Participated in other similar clinical trials within 6 months.
* 9\. subjects currently receiving treatment for other gene therapy.
* 10\. subjects combined with graft versus host disease (GVHD).
* 11\. Other subjects judged by the researchers to be unsuitable for admission to the study.