Newly-diagnosed Low Risk Pediatric B-cell ALL Protocol

Inclusion Criteria: Must meet all items below: 1. Age older than 1 year and younger than 18 years. 2. Diagnosis of acute lymphoblastic leukemia by bone marrow morphology. 3. Diagnosis of B-ALL by immunophenotyping. 4. Low risk group Exclusion Criteria: Should be excluded in the presence of any item below: 1. T-ALL 2. I/HR B-ALL group 3. sIgM+ 4. Acute leukemias of ambiguous lineage diagnosed according to WHO or EGIL criteria. 5. Philadelphia chromosome positive ALL (Ph-ALL) 6. ALL evolved from chronic myeloid leukemia (CML). 7. Down's syndrome, or major congenital or hereditary disease with organ dysfunction 8. Secondary leukemia 9. Known underlying congenital immunodeficiency or metabolic disease 10. Congenital heart disease with cardiac insufficiency. 11. Glucocorticoid treatment for ≥14 days, or ABL kinase inhibitors for \> 7 days within one month before enrollment, or any chemotherapy or radiotherapy within 3 months before enrollment (except for emergency radiotherapy to relieve airway compression)