This study aimed to evaluate the efficacy of reduced intensity conditioning (RIC) regimen in low- and intermediate-risk myelodysplastic syndrome (MDS) patients who receive haploidentical hematopoietic stem cell transplantation (haplo-HSCT). Haplo-HSCT is an effective treatment option for MDS patients who did not have identical sibling donor (ISD) or unrelated donor (URD). However, post-transplant transplant-related mortality (TRM) is one of the major causes for transplant failure in MDS patients, and the risk of TRM for haplo-HSCT recipients was higher than that of ISD recipients. RIC regimen can decrease the risk of TRM for haplo-HSCT recipients; however, the risk for relapse may increase in these patients. Thus, RIC regimen may be more appropriate for low- and intermediate-risk MDS patients receiving haplo-HSCT. The study hypothesis: Using RIC haplo-HSCT regimen in patients with low- and risk MDS can reduce TRM and improve survival.

RIC regimen was given for low and intermediate MDS patients who would receive haplo-HSCT. The primary end point was transplant-related mortality. The secondary end points were overall survival, disease-free survival, relapse, , graft-versus-host disease (GVHD), and infections. Following time is 1 years.

Inclusion Criteria:

• Patients who had low- and intermediate-risk MDS without ISD nor URD receiving haploidentical hematopoietic stem cell transplantation

Exclusion Criteria:

• Patients having ISD or URD; patients having high-risk MDS; patients with active infection; patients with poor compliance; patients with organ failure