Objective      To determine the effect of allogenic hematopoietic stem cell transplantation (Allo-HSCT) combined with imatinib on Philadelphia positive acute lymphoblastic leukemia (ALL).       Methods      Twenty Philadelphia positive ALL patients received Allo-HSCT combined with imatinib in our department from March 2008 to March 2010. There were HLA-identical sibling HSCT in 9 cases

HLA-haplotype sibling HSCT in 6 cases

HLA-identical unrelated HSCT in 3 cases

and HLA-mismatched unrelated HSCT in 2 cases. All patients were given the treatment of chemotherapy combined with imatinib after diagnosis. In 2 weeks before transplantation to hematopoietic reconstitution

imatinib was stopped to administer. After hematopoietic function was stabilized

treatment of imatinib was continued. The level of BCR/ABL mRNA was monitored using real-time PCR and fluorescence in situ hybridization (FISH). The last follow-up was carried out in March 2012.       Results      Chemotherapy combined with imatinib treatment resulted in complete response in all 20 patients before HSCT. The level of BCR/ABL mRNA was declined and reached to zero level. All 20 patients achieved stable engraftments without severe transplantation related complications. Until March 2012

15 of the 20 patients’ bone marrow continued CR

and BCR/ABL fusion gene continued negative

and 5 of the 20 patients relapsed.       Conclusion      Allo-HSCT combined with imatinib is an effective regimen for Philadelphia positive ALL.