This is a single center,randomized ,two-cohorts, open-label ,phase 1/2 study to evaluate the efficacy and safety of T cells expressing CD19 chimeric antigen receptors combined with CD19 positive feeder T cells treatment for CD19+ acute lymphoblastic leukemia patients in remission .

Patients were divided into two groups, group 1 and group 2, and each group was enrolled in 5 patients. Group 1 patients did not receive any pretreatment, and group 2 patients received pretreatment with cyclophosphamide and fludarabine prior to reinfusion. Then Patients were given Chimeric Antigen Receptor T-Cell( CAR-T) and CD19-positive T cells.

Inclusion Criteria:

1. Age 18 to 65
2. Voluntary informed consent is given
3. Expected survival ≥12 weeks
4. Relieve CD19+ acute leukemia
5. Organ function: (1)Left ventricular ejection fractions≥ 0.6 by echocardiography (2)ALT ≤3 times of ULN, or bilirubin <2.0 mg/dl (3)Creatinine < 2 mg/dl and less than 2.5 × normal for age (4)Prothrombin time and activated partial thromboplastin time < 2 times of ULN (5)Arterial oxygen saturation> 92%
6. Karnofsky score ≥ 60 ;
7. No history of combined chemotherapy in the recent 1 month and no immunotherapy in the recent 3 months;

Exclusion Criteria:

1. Uncontrolled active infections
2. Active hepatitis B or hepatitis C infection
3. HIV infection
4. History of myocardio infarction in the past 6 months, or history of severe arrhythmia
5. Congenital immunodeficiency
6. Pregnant or lactating women
7. History or presence of clinically relevant CNS pathology such as epilepsy, generalized seizure disorder, paresis, aphasia, stroke, severe brain injuries, dementia, Parkinson's disease, cerebellar disease, organic brain syndrome, or psychosis
8. Previous treatment with any gene therapy products