This study aims to evaluate the safety and efficacy of a novel CD19-CART in the treatment of refractory or recurrent ALL.

Chimeric antigen receptor T cell (CART) is a kind of engineered immunotherapy by transferring an artificial antigen binding receptor and also intercellular co-stimulating molecules into T cells. This kind of engineered T cells gains the ability to recognize antigen specific tumor cells and initiate the killing process in a HLA-independent way. CD19 is the specific cellular marker of B lineage acute leukemia (B-ALL), thus CD19-CART will be efficient in treating B lineage ALL. The investigators have constructed two kinds of CD19-CART. One is equipped with a murine CD19 scFv (single-chain variable fragmentt), while the other with a humanized scFv. This study aims to evaluate the safety and efficacy of both murine and humanized CD19-CART in treating refractory or recurrent ALL.

Inclusion Criteria:

1. previously identified as CD19+ ALL.
2. ALL patients not eligible for allogeneic SCT or relapse after allogeneic SCT.
3. Expected survival >12W.
4. Creatinine < 2.5 mg/dl.
5. Alanine transaminase (ALT)/Aspartate Aminotransferase (AST) < 3x normal
6. Bilirubin <2.0 mg/dl
7. Voluntary informed consent is given.

Exclusion Criteria:

1. Pregnant or lactating women.
2. Uncontrolled active infection.
3. Active hepatitis B or hepatitis C infection.
4. Concurrent use of systemic steroids. Recent or current use of inhaled steroids is not exclusionary.
5. Previously treatment with any gene therapy products.
6. Any uncontrolled active medical disorder that would preclude participation as outlined.
7. HIV infection.