Objective: To evaluate the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) from different donors as first-line treatment for children and adolescents with severe aplastic anemia (SAA) . Methods: The clinical data of 79 children and adolescents with SAA diagnosed from January 2013 to December 2016 in Henan Province were retrospectively analyzed. There were 50 males and 29 females, with a median age of 14(4-18) years. 40 cases received matched sibling transplantation (MSD-HSCT), 17 with unrelated donor transplantation (UD-HSCT), and 22 with haploidentical transplantation (haplo-HSCT). Results: The comparison of MSD-HSCT, UD-HSCT, haplo-HSCT groups was conducted and the median times of neutrophils engraftment were statistically significant [12(9-25) d, 14(10-22) d, 16(11-26) d, respectively (χ²=13.302, P=0.001)], but no difference in+30 d engraftment rate [97.3%(36/37), 100%(15/15), 100%(20/20), χ²=0.959, P=0.619]. The median times of PLT engraftment were not statistically significant [14(6-34)d, 16(7-32)d, 19(10-34)d, respectively, χ²=5.892, P=0.053], and the +30 d engraftment rate had no difference [97.3%(36/37), 100%(15/15), 100%(20/20), χ²=0.959, P=0.619]. The post-transplant infection rate showed no statistically significance [35.0% (14/40), 29.4% (5/17), 45.5% (10/22), χ²=1.158, P=0.560], as well as the incidences of aGVHD, grade III/IV aGVHD and cGVHD(χ²=0.230, P=0.891; χ²=2.628, P=0.269; χ²=3.187, P=0.203). The two-years OS rate was not statistically significant respectively [(77.1±6.7)%, (70.6±11.1)%, (77.3±8.9)%, χ²=0.330, P=0.845]. Severe post-transplant infection (RR=4.617, P=0.009), grade Ⅲ/Ⅳ aGVHD (RR=2.707, P=0.048) were independent risk factors for OS. Conclusion The overall efficacy of MSD-HSCT, UD-HSCT and haplo-HSCT as first-line therapy for children and adolescents with SAA/VSAA is comparable.

Objective:To explore the strategies of reducing relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with high-risk myelodysplastic syndrome (MDS) from the perspectives of optimizing the conditioning regimen and pre-transplant cytoreductive therapy.Methods:A total of 84 patients with high-risk MDS undergoing allo-HSCT between January 2013 and September 2019 were retrospectively analyzed. Based upon preparative regimens, they were divided into two groups of decitabine intensified BUCY2 ( n=49) and BUCY2 regimen ( n=35), based upon whether or not pre-treatment prior to allo-HSCT: cytoredutive treatment ( n=34) and none ( n=50). Two groups were compared with regards to hematopoietic reconstitution, graft-versus-host disease (GVHD), relapse rate, transplant-related mortality (TRM) and survival. Results:No significant inter-group differences existed in hematopoietic reconstitution or acute/chronic GVHD. The relapse rate was significantly lower in decitabine intensified group than that in BUCY2 group (18.7% vs 40.0%, P=0.025). Survival was significantly better in decitabine intensified group than that in BUCY2 group (3-year OS: 71.3% vs 51.2%, P=0.038; 3-year DFS: 65.3% vs 45.2%, P=0.033). Moreover, the incidence of recurrence was markedly lower in pre-transplant treatment group than that in non-treatment group (20.7% vs 38.9%, P=0.035). The inter-group incidence of TRM was not different. Three-year OS/DFS of treatment group were remarkably superior to those of non-treatment group (71.2% vs 50.8%, P=0.024; 64.7% vs 45.9%, P=0.044). Conclusions:As an optimal conditioning regimen for high-risk MDS, decitabine intensified BUCY2 regimen could better eliminate tumor burden, remarkably lower relapse rate and improve OS after allo-HSCT. In addition, pre-transplant treatment significantly reduces relapse and offers benefit for OS after allo-HSCT. Therefore intensified conditioning regimen and pre-transplant treatment may be promising strategies of reducing relapse and improving survival for high-risk MDS. However, it still needs further confirmation from prospective randomized controlled trials.

Objective To explore the role of cerebrospinal fluid chimerism in central nervous relapse surveillance for patients of acute leukemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Methods The follow-up data were retrospectively collected and analyzed in 104 patients with acute leukemia after allo-HSCT.Comparisons were made between patients with complete chimerism and mixed chimerism in cerebrospinal fluid.The role of recipient DNA percentage and its changing trend in predicting central nervous relapse were also explored.Analysis was conducted for determining the risk factors of central nervous relapse.And the effectiveness of prophylaxis with intrathecal injection was also examined.Results The incidence of relapse was higher in patients with mixed chimerism (P＜0.001),high percentage of recipient DNA (P＜0.05) and higher mixed chimerism (P＜0.001).Hyperleukocytosis at an initial diagnosis was a risk factor of central nervous relapse.Whether or not intrathecal injection prophylaxis was applied showed no significant difference in relapsing rate.Conclusions Monitoring cerebrospinal fluid chimerism can effectively help predict central nervous relapse among patients of acute leukemia after allo-HSCT.Yet intrathecal injection prophylaxis failed to benefit recipients.