ORIGINAL ARTICLE HLA-mismatched hematopoietic SCT without in vitro T-cell depletion for myelodysplastic syndrome Y Chen, K Liu, L Xu, H Chen, D Liu, X Zhang, H Shi, W Han, Y Wang, T Zhao, J Wang, J Wang and X Huang Peking University Institute of Hematology, People’s Hospital, Peking University, Beijing, PR China Allogeneic hematopoietic SCT (HSCT) is currently the only curative treatment for myelodysplastic syndrome (MDS). However, many patients cannot find an HLA- matched donor. We have developed a new protocol for HLA-mismatched (including haploidentical) HSCT using G-CSF-primed BM plus G-CSF-mobilized PBSCs with- out in vitro T-cell depletion. A total of 36 patients diagnosed with high-risk MDS (RAEB (refractory anemia with excess blasts) or RAEBt (RAEB in transformation)) underwent transplantation from HLA-mismatched family donors. All patients achieved sustained myeloid engraft- ment. The cumulative incidence of grades II–IV acute GVHD (aGVHD) was 60% and that of grades III and IV aGVHD was 15%. The 2-year cumulative incidence of chronic GVHD was 56%. After a median follow-up of 17 months, 4 patients had relapsed and died and 25 patients were still alive. The 2-year probability of leukemia-free survival (LFS) was 65%. Patients transplanted within 7 months of diagnosis had better LFS (89 vs 43% ). Severe aGVHD decreased the LFS significantly by increasing non-relapse mortality (NRM). This study confirms that HLA-mismatched HSCT is a treatment option for MDS. Patients with high-risk MDS benefit from receiving HSCT early in the course of the disease. Bone Marrow Transplantation (2010) 45, 1333–1339; doi:10.1038/bmt.2009.351; published online 11 January 2010 Keywords: myelodysplastic syndrome; hematopoietic SCT; allogeneic; HLA; haploidentical; mismatched Introduction Allogeneic hematopoietic SCT (HSCT) is the only curative treatment available for high-risk myelodysplastic syndrome (MDS). 1 Donor availability limits the use of HSCT, and the use of alternative donors is worth exploring. We have recently developed a new method for HLA-mismatched/ haploidentical HSCT using G-CSF-primed BM (G-BM) plus G-CSF-mobilized PBSCs (G-PB) without ex vivo T-cell depletion after conditioning with a modified BU/CY2 plus thymoglobuline (ATG) regimen. The results for this novel method in acute leukemia and chronic myeloid leukemia patients are promising. 2,3 However, there has been no report on its effects on MDS until now. We report the results of HSCT from haploidentical/ mismatched donors in 36 MDS patients using this protocol. Patients and methods A total of 36 consecutive patients who were diagnosed with MDS and received an HLA-mismatched allogeneic HSCT without in vitro T-cell depletion from April 2003 to September 2008 at the Peking University Institute of Hematology, People’s Hospital, were analyzed. The in- stitutional review board at the Peking University Institute of Hematology approved the protocol, and all patients or their guardians signed consent forms approved by the institutional review board. Myelodysplastic syndrome was originally diagnosed by the FAB criteria 4 and then more recently reclassified according to the criteria defined by the World Health Organization (WHO). 5 The International Prognostic Scor- ing System (IPSS) was used to categorize the patients into different risk groups. 6 Only patients who were diagnosed with MDS-refractory anemia with excess blasts (RAEB) or MDS-RAEB in transformation (RAEBt) were included. The enrolled patients met the following criteria: no available HLA-identical related or unrelated donors, sufficient cardiac function, creatinine clearance 470 ml/ min, lung diffusion capacity of at least 80%, transaminases less than three times the upper limit of normal, Karnofsky performance status X80% and no active infections. Five patients had been reported on in a previous paper. 2 Patient characteristics are summarized in Table 1. Follow- up for all patients extended through to 31 January 2009. Donors Family members were assessed for the degree of mismatch. HLA-A and HLA-B typing was performed by Received 10 March 2009; revised 15 September 2009; accepted 20 September 2009; published online 11 January 2010 Correspondence: Professor X Huang, Peking University Institute of Hematology, People’s Hospital, Peking University, No.11, Xizhimen South Street, Xicheng District, Beijing 100044, PR China. E-mail: xjhrm@medmail.com.cn Bone Marrow Transplantation (2010) 45, 1333–1339 & 2010 Macmillan Publishers Limited All rights reserved 0268-3369/10 www.nature.com/bmt