评估异基因造血干细胞移植（allo-HSCT）联合脱氧胞苷（Dec）预处理方案治疗骨髓增生异常综合症（MDS）和MDS转化为急性髓细胞白血病（MDS-AML）的疗效和安全性。回顾性分析了2013年4月至2021年11月在我们中心接受allo-HSCT治疗的93名MDS和MDS-AML患者的特征和疗效数据。所有患者均通过髓毒性预处理方案，包含Dec（25 mg/m2/d×3 d）。在93名患者中，有63名男性和30名女性，被诊断为MDS（n=77）和MDS-AML（n=16）。I/II级方案相关毒性（RRT）的发生率为39.8％，III级RRT仅在1名患者（1％）中发现。中位中性粒细胞植入时间为14（9-27）天，91名（97.8％）患者成功植入中性粒细胞；成功的血小板植入在87名（93.5％）患者中实现，中位植入时间为18（9-290）天。急性移植物抗宿主病（aGVHD）和III-IV级aGVHD的发生率分别为44.2％和16.2％。慢性移植物抗宿主病（cGVHD）和中度至重度cGVHD的发生率分别为59.5％和37.1％。在93名患者中，有54名（58％）发生移植后感染，其中肺部感染（32.3％）和血流感染（12.9％）最常见。移植后中位随访时间为45（0.1-108）个月。5年总生存率（OS）、无病生存率（DFS）、治疗相关死亡率和复发累积发生率分别为72.7％、68.4％、25.1％和6.5％。1年移植物抗宿主病/复发无病生存率为49.3％。不同相对高危预后评分组或低危预后评分组、带或不带劣势突变的患者、突变数≥3或<3的患者具有相似的5年OS率（超过70％）。多元分析显示，III-IV级aGVHD的发生率是影响OS（P=0.008）和DFS（P=0.019）的独立危险因素。allo-HSCT与Dec预处理方案在MDS和MDS-AML患者中的治疗可行性和疗效良好，特别是在高预后危险和带有劣势突变的患者中。

To evaluate the efficacy and safety of allogeneic hematopoietic stem cell transplantation (allo-HSCT) with decitabine (Dec)-conditioning regimen in the treatment of myelodysplastic syndrome (MDS) and MDS transformed acute myeloid leukemia (MDS-AML).The characteristics and efficacy data of 93 patients with MDS and MDS-AML who received allo-HSCT in our center from April 2013 to November 2021 were retrospectively analyzed. All patients were administered by myeloablative conditioning regimen containing Dec (25 mg/m2 /d×3 d).Among the 93 patients, 63 males and 30 females, were diagnosed as MDS（n ＝77）, MDS-AML（n ＝16）. The incidence of I/II grade regimen-related toxicity (RRT) was 39.8%, and III grade RRT was only found in 1 patient (1%). Neutrophil engraftment was successful in 91 (97.8%) patients after a median neutrophil engraftment time of 14 (9-27) days; Successful platelet engraftment was achieved in 87 (93.5%) patients, with a median engraftment time of 18 (9-290) days. The incidence of acute graft versus host disease（aGVHD） and grade III-IV aGVHD was 44.2% and 16.2%, respectively. The incidence of chronic graft versus host disease（cGVHD） and moderate-to-severe cGVHD was 59.5% and 37.1%, respectively. Of the 93 patients, 54 (58%) developed posttransplant infections, among which lung infection (32.3%) and bloodstream infection (12.9%) were the most common. The median follow-up after transplantation was 45 (0.1-108) months. The 5-year overall survival (OS) rate, disease-free survival (DFS) rate, treatment-related mortality, and cumulative incidence of relapse were 72.7%, 68.4%, 25.1%, and 6.5%, respectively. And the 1-year graft-versus-host disease/relapse-free survival rate was 49.3%. The patients in different group of relative high-risk prognostic scoring or low-risk prognostic scoring, with or without poor-risk mutation(s), with mutations number ≥3 or <3 had similar 5-year OS rate (more than 70%). Multivariate analysis showed that the incidence of grade III-IV aGVHD was the independent risk factor affecting OS（P =0.008）and DFS (P =0.019).Allo-HSCT with Dec-conditioning regimen is feasible and effective in the treatment of patients with MDS and MDS-AML, especially those in high prognostic risk and with poor-risk mutations.