The effects of haploidentical rhG-CSF-mobilized unmanipulated blood and marrow transplantation (HBMT) on hematological malignancies are well established.The aim of this prospective cohort trial is to determine if acute graft-versus-host disease (aGVHD) could be decreased with IL2 therapy post HBMT.

The effects of haploidentical rhG-CSF-mobilized unmanipulated blood and marrow transplantation (HBMT) on hematological malignancies are well established.The aim of this prospective cohort trial is to determine if acute graft-versus-host disease (aGVHD) could be decreased with IL2 therapy post HBMT.low dose of IL-2 (40 million U/m2) will be administered from WBC engraftment to day 90 post haploidentical transplantation. IL-2 will be administered three times a week.

Inclusion Criteria:

1. Aged 15-65 years old
2. Acute leukemia in complete remission (CR1/CR2) who received myeloablative haploidentical allo-HSCT
3. WBC engraftment (ANC>500/ul for continuous 3 days)
4. At least +7d
5. Less than or equal to +15d
6. non T-ALL
7. no active II-IV aGVHD
8. no severe infections
9. Karnofsky score greater than or equal to 90%
10. Haploidentical donor from sibling, children or father
11. Ensure that informed consent signed and faxed to Research Coordinator

Exclusion Criteria:

1. Exposure to any other clinical trials prior to enrollment
2. Active malignant disease relapses or MRD positive
3. Active, uncontrolled infection
4. Inability to comply with IL-2 treatment regimen
5. Active, uncontrolled II-IV aGVHD
6. Haploidentical donor from mother or collateral donors
7. Clinical Signs of severe pulmonary dysfunction
8. Clinical Signs of sever cardiac dysfunction
9. Receiving corticosteroids as GVHD treatment