OBJECTIVETo observe the treatment effect and toxicity of nonmyeloablative allogeneic stem cell transplantation (NST) for hematologic diseases.

METHODSA total of 243 hematologic diseases patients received HLA-identical NST were enrolled in this study from 9 transplant centers of NST Cooperative Group in China. Nonmyeloablative conditioning regimen was based on fludarabine (Flud), rabbit anti-human thymocyte globulin (ATG), cyclophosphamide (CTX) (FAC), and plus cytarabine or busulfan (BU) etc. Graft-versus-host disease (GVHD) prophylaxis included cyclosporin A (CsA) and mycophenolate mofetil (MMF).

RESULTSAmong the 243 patients, 219 (90.1%) achieved full donor chimerism (FDC), 2(0.8%) engraftment failure. 78 (32.1%) had mixture chimerism (MC) at 4 weeks after NST, out of which 56 switched to FDC, 16 remained MC and 6 (2.5%) developed graft rejection. The incidence of acute GVHD was 34.2%, including 6.6% of grade III-IV acute GVHD. Chronic GVHD developed in 78 (32.1%) patients. The follow-up durations were 3 - 99 months, 162 (66.7%) were still alive and the overall survival rates were 76.5%, 73.9%, 70.7%, and 27.8% for MDS/SAA, chronic myeloid leukemia, acute leukemia at first remission, and refractory or relapsed leukemia, respectively.

CONCLUSIONSThe nonmyeloablative allogeneic stem cell transplantation based on FAC conditioning results in sustained engraftment and mild aGVHD, providing a new feasible curative therapy for hematology diseases.