Aim: to observe the graft versus tumor effect of Pegylated Interferonα-2b in patients with hematological malignancies relapsed after allogeneic hematopoietic stem cell transplantation (alloHSCT) Patients: patients relapsed after alloHSCT, men and women aged 14-60 years, without vital organ dysfunction or ongoing graft-verus-host disease (GVHD).

Number of subjects: 50, Single center, one group, prospective. Drug: pegylated interferon alpha-2b (Peg Intron®; Schering-Plough) 1~1.5ug/kg qw, until occurrence of grade II or higher grade of acute GVHD, or no response to treatment after 8 doses of treatments.

Eligible patients were age 14 to 60 years with molecular, hematological or radiography relapsed hematological malignancies post allogeneic hematopoietic stem cell transplantation.

Molecular relapse was defined as reappearance or 1 log increase of molecular markers or decreasing donor chimerism by more than 5%; Hematological relapse was defined as reappearance of blast in bone marrow smear by more than 5%; radiography relapse was defined as enlargement of lymph nodes by more than 25% or infiltration of tumor cells in other sites.

Patients were excluded if they need immunosuppressant treatment for ongoing grade II～IV acute GVHD or moderate to severe chronic GVHD.

Eligible patients were treated with pegylated interferon alpha-2b (Peg Intron®; Schering-Plough (Brinny) Company, Innishannon, County Cork, Ireland) 1~1.5ug/kg qw, until occurrence of grade II or higher grade of acute GVHD, or no response to treatment after 8 doses of treatments. Patients were followed up every week. Physical exams and blood tests including complete blood count (CBC), chemical were performed every week. Disease status evaluation was performed every month.

Number of subjects: 50 Single center, one group, prospective.

Inclusion Criteria:

1. Age 14-60 years, male or female
2. Allo-HSCT recipients with malignant hematological diseases
3. Disease relapse after allo-HSCT, including hematological relapse, molecular relapse
4. Able to provide written informed consent and to comply with all study procedures

Exclusion Criteria:

1. Pregnant or nursing woman
2. Cardiac ejection factor < normal lower limit
3. Active acute or chronic GVHD with immunosuppressant treatment
4. Known hypersensitivity or allergy to interferon
5. Patient might develop serious complications according to investigator's experiences
6. Patient is undergoing other experimental medication

There is no plan to make individual participant date available before publication