Phase II Study of Anti-CD19 CAR-T Cells Treating Leukemia Children

Inclusion Criteria:

* Patients who were diagnosed as primary refractory or relapsed B-ALL. All the patients matched the diagnostic criteria of ALL according to the WHO classification and conducted morphological evaluation, immunophenotype analysis by flow cytometry (FCM), cytogenetic analysis by routine G-banding karyotype analysis, screen of 56 leukemia-related fusion genes by multiplex nested reverse transcriptase-polymerase chain reaction (RT-PCR), and quantification of fusion genes by real-time PCR with ABL1 as reference. Extramedullary diseases (EMDs) were confirmed CD19+ by FCM and evaluated by positron emission tomography/computed tomography (PET/CT), CT, MRI or ultrasonography. The patient relapsed during chemotherapy or failed from re-induction chemotherapy (including first and second-generation TKIs) after relapse or had a persistent positive minimal residual disease (MRD) for three months. Patients had positive CD19 expression on leukemia blasts by FCM (\>95% CD19 positive);
* Age from 0 to 18 years old;
* Children candidates can be recruited after the legal guardian or patient advocate has signed the treatment consent form and voluntary consent form;

Exclusion Criteria:

* Intracranial hypertension or unconscious;
* Acute heart failure or severe arrhythmia;
* Acute respiratory failure;
* Other types of malignant tumors;
* Diffuse intravascular coagulation;
* Serum creatinine and/or blood urea nitrogen over 1.5 times than normal range;
* Sepsis or other uncontrolled infection;
* Uncontrolled diabetes mellitus;
* Severe psychological disorder;
* Obvious cranial lesions with cranial MRI;
* More than 20 counts/ul leukemic cells in cerebrospinal fluid;
* More than 30% leukemic cells in the blood;
* Stage III WHO/ECOG score;
* Organ recipients;
* Pregnant or breastfeeding;
* Active, uncontrolled infection, including hepatitis B, hepatitis C or human immunodeficiency virus (HIV);