The purpose of this study is to evaluate the safety and efficacy of IFN-α combined with CAR-T cell therapy in relapsed and refractory acute lymphoblastic leukemia (R/R ALL).

This is a phase 2, single-center study. The patients will receive IFN-α combined with infusion of CAR T-cells in R/R B-ALL patients. The study participation will be 5 years including treatment and follow-up periods.

Inclusion Criteria:

1. Diagnosed refractory and relapsed acute B-lymphoblastic leukemia.
2. Age 12-65.
3. Eastern Cooperative Oncology Group (ECOG) score 0-2.
4. Target on leukemia is >20% positive detected with flowcytometry.
5. Patients with left ventricular ejection fraction ≥ 0.5 by echocardiography or grade I/II cardiovascular dysfunction according to the New York Heart Association Classification.

5.Patients with aspartate aminotransferase or glutamic-pyruvic transaminase > 3x upper limit of normal or bilirubin > 2.0 mg/dL.

6.No other immunotherapy was received within 3 months.

Exclusion Criteria:

1. Patients are pregnant or lactating.
2. Patients with congenital immunodeficiency.
3. Patients with central nervous system leukemia.
4. Patients with uncontrolled active infection.
5. Patients with active hepatitis B or hepatitis C infection.
6. Patients with HIV infection.
7. Patients with atrial or venous thrombosis or embolism.
8. Patients with myo-infarction or severe arrythmia in the recent 6 months.
9. Other comorbidities that investigators considered not suitable for this study.