Phase I Study of CD19-CAR-T2 Cells for Patients With Chemotherapy Resistant or Refractory CD19+ Acute Leukemia

Inclusion Criteria:

* Patient with relapsed and/or refractory CD19 positive B-cell acute leukemia
* Eastern Cooperative Oncology Group (ECOG) performance status 《 3
* ALT/ AST 《 3x normal
* Bilirubin \< 2.0 mg/dl
* Creatinine \< 2.5 mg/dl and less than 2.5x normal for age
* LVEF》 45%
* Accept white blood cell collection
* Provide informed consent

Exclusion Criteria:

* Previous treatment with investigational gene or cell therapy medicine products
* Solitary extramedullary relapse
* Active hepatitis B , hepatitis C or HIV infection
* Uncontrolled active infection
* Presence of grade 2-4 acute or extensive chronic GVHD
* Active CNS involvement: epilepsy, paresis, aphasia, stroke, severe head trauma,
* Dementia, Parkinson's disease, cerebellar disease, organic brain syndrome, uncontrolled mental illness, etc.
* Any uncontrolled active medical disorder that would preclude participation as outlined.
* Received non-diagnostic purposes major surgery within the past 4 weeks
* Participated in any other clinical study within the past 4 weeks
* Used murine biological products (except blinatumomab), unless it is proved no anti-mouse antibodies exist.
* Pregnancy or breast-feeding women
* Use of prohibited drugs:
* Steroids: Therapeutic doses of steroids must be stopped \> 72 hours prior to CD19-CAR-T2 Cells infusion
* Allogeneic cellular therapy: Any donor lymphocyte infusions (DLI) must be completed \> 4 weeks prior to CD19-CAR-T2 Cells infusion
* GVHD therapies: Any drug used for GVHD must be stopped \> 4 weeks prior to CD19-CAR-T2 Cells infusion
* Chemotherapy: i. The following drugs must be stopped \> 1 week prior to CTL019 infusion and should not be administered concomitantly or following lymphodepleting chemotherapy: hydroxyurea, vincristine, 6-mercaptopurine, 6-thioguanine, methotrexate \<25 mg/m2, cytosine arabinoside \< 10 mg/m2/day, asparaginase; ii. The following drugs must be stopped \> 4 weeks prior to CTL019 infusion: salvage chemotherapy (e.g. clofarabine, cytosine arabinoside \> 100 mg/m2, anthracyclines, cyclophosphamide), excluding the required lymphodepleting chemotherapy drugs
* Any situation that may increase the risk of the test or interfere with the test results