β-Thalassemia is a global health issue, caused by mutations in the HBB gene. Among these mutations, HBB −28 (A>G) mutations is one of the three most common mutations in China and Southeast Asia patients with β-thalassemia. Correcting this mutation in human embryos may prevent the disease being passed onto future generations and cure anemia. Here we report the first study using base editor (BE) system to correct disease mutant in human embryos. Firstly, we produced a 293T cell line with an exogenous HBB −28 (A>G) mutant fragment for gRNAs and targeting efficiency evaluation. Then we collected primary skin fibroblast cells from a β-thalassemia patient with HBB −28 (A>G) homozygous mutation. Data showed that base editor could precisely correct HBB −28 (A>G) mutation in the patient’s primary cells. To model homozygous mutation disease embryos, we constructed nuclear transfer embryos by fusing the lymphocyte or skin fibroblast cells with enucleated in vitro matured (IVM) oocytes. Notably, the gene correction efficiency was over 23.0% in these embryos by base editor. Although these embryos were still mosaic, the percentage of repaired blastomeres was over 20.0%. In addition, we found that base editor variants, with narrowed deamination window, could promote G-to-A conversion at HBB −28 site precisely in human embryos. Collectively, this study demonstrated the feasibility of curing genetic disease in human somatic cells and embryos by base editor system.Electronic supplementary materialThe online version of this article (doi:10.1007/s13238-017-0475-6) contains supplementary material, which is available to authorized users.

We investigated the efficacy of allogeneic hematopoietic stem cell transplantation (alloHSCT) in pediatric patients with mucopolysaccharidosis (MPS). A retrospective analysis of transplantation data from 34 cases of MPS from the China Children Transplant Group, treated between December 2004 and September 2015, was conducted. Among the 34 cases, 12 cases were type I, 12 were type II, 4 were type IV, 4 were type VI, and 2 were of an unknown type. The median age at transplantation was 3.75 years (range, 1 to 7 years); the median follow-up time was 14 months (range, 2 to 119 months). Eleven patients underwent unrelated cord blood transplantation and 23 underwent peripheral blood stem cell transplantation (4 cases with an HLA-matched sibling donor, 2 cases with an HLA-mismatched related donor, and 17 cases with an unrelated donor). A busulfan-based myeloablative regimen was used as a conditioning regimen. The estimated overall survival at 3 years was 84.8% ± 6.3% and 91.2% of the patients (31 of 34) achieved full donor chimerism. Twenty-seven children were evaluable and all but 1 (carrier sibling donor; enzyme level improved but failed to reach normal) achieved normal enzyme level after transplantation. The incidence of grades II to IV acute graft-versus-host disease (aGVHD) was 41.1% (14 of 34), wherein the incidence of grades III and IV aGVHD was 11.8% (4 of 34). The incidence of moderate-to-severe chronic graft-versus-host disease was 5.9% (2 of 34). There was a significant difference in the survival rate between children who received transplantation before 2009 and those after 2009 (55.6% versus 95.7%, P = .002); the survival rate was lower in patients with pneumonia before transplantation than in those with no active infection before transplantation (66.7% versus 95.5%, P = .019), and no significant differences in survival rates were observed among children with different disease types, ages at transplantation, donor/graft source, and conditioning regimens. After transplantation, upper-airway obstruction, hepatosplenomegaly, and corneal clouding were significantly improved; hearing and motor function were improved to a certain extent; valvular heart disease was improved in some patients but progressed in others; and short stature and speech skills showed little improvement. AlloHSCT may save the lives of patients with MPS I, II, IV or VI and could improve quality of life. Pretransplantation pneumonia affects transplantation outcomes. Advances in transplantation protocols and techniques help to improve patient prognosis. Well-matched unrelated donors can also be an ideal donor source. Standardized follow-up and a multidisciplinary team contribute to accurate evaluation of long-term post-transplantation outcome and further improve the quality of life of MPS patients.

OBJECTIVES: Although it is widely believed that China is facing a major shortage of pediatricians, the real situation of the current national status of pediatric human resources and their working conditions has not been evaluated to date. METHODS: We administered a survey to 54 214 hospitals from all 31 provinces in mainland China from 2015 to 2016. Hospital directors of all secondary and tertiary hospitals with pediatric services and a random sample (10%) of primary hospitals provided information on number of pediatricians and their educational levels, specialties, workloads, dropout rates, and other hospital characteristics. A data set of medical resources and socioeconomic information regarding each region (1997–2016) was constructed from the Chinese National Statistics Bureau. The Gini coefficient was used to describe the geographical distributions of pediatricians and hospitals. RESULTS: There were 135 524 pediatricians in China or ∼4 pediatricians per 10 000 children. Pediatricians’ average educational level was low, with ∼32% having only 3 years of junior college training after high school. The distribution of pediatricians was extremely skewed (Gini coefficient 0.61), and the imbalance of highly educated pediatricians was even more skewed (Gini coefficient 0.68). The dropout rate of pediatricians was 12.6%. Despite an increase in the Chinese government’s financial investment in health over the last decade, physicians have been burdened with a greater workload. CONCLUSIONS: Uneven development of the pediatric care system, inadequately trained pediatricians, low job satisfaction, and unmet demand for pediatric care are the major challenges facing China’s pediatric health care system.

Studies on the clinical significance of Nucleophosmin (NPM1) mutations in pediatric AML in a large cohort are lacking. Moreover, the prognosis of patients with co-occurring NPM1 and FLT3/ITD mutations is controversial. Here, we analyzed the impact of NPM1 mutations on prognoses of 869 pediatric AML patients from the TAGET dataset. The frequency of NPM1 mutations was 7.6%. NPM1 mutations were significantly associated with older age (P < 0.001), normal cytogenetics (P < 0.001), FLT3/ITD mutations (P < 0.001), and high complete remission induction rates (P < 0.05). Overall, NPM1-mutated patients had a significantly better 5-year EFS (P = 0.001) and OS (P = 0.016) compared to NPM1 wild-type patients, and this favorable impact was maintained even in the presence of FLT3/ITD mutations. Stem cell transplantation had no significant effect on the survival of patients with both NPM1 and FLT3/ITD mutations. Multivariate analysis revealed that NPM1 mutations were independent predictors of better outcome in terms of EFS (P = 0.004) and OS (P = 0.012). Our findings showed that NPM1 mutations confer an independent favorable prognostic impact in pediatric AML despite of FLT3/ITD mutations. In addition, pediatric AML patients with both NPM1 and FLT3/ITD mutations appear to have favorable prognoses and may not need hematopoietic stem cell transplantations.

The role and potential efficacy of antithymocyte globulin (ATG) in patients receiving cord blood transplantation (CBT) remain controversial. We retrospectively evaluated the effect of ATG on patient outcomes in 207 children with high-risk or advanced hematological malignancies at 8 child blood disease centers in China. The cumulative incidence of platelet recovery on day 100 was significantly lower in the ATG cohort compared with the non-ATG cohort (77.3% versus 89.8%) (P = .046). There was no significant difference in the incidence of grade II to IV acute and chronic graft-versus-host disease (GVHD), and transplantation-related mortality (TRM) between the 2 groups (P = .76, P = .57, and P = .46, respectively). The incidence of CMV infection was significantly higher among the ATG group compared with that among the non-ATG group (P = .003). The 5-year cumulative incidence of relapse was significantly higher in the ATG cohort (30.7% versus 15.4%) (P = .009). Overall survival in the non-ATG group was slightly higher than that of the ATG cohort (64.1% versus 52.1%, P = .093) and leukemia-free survival in the non-ATG cohort was significantly higher than in the ATG cohort (56.6% versus 37.7%, P = .015). Our study demonstrated that, for high-risk or advanced childhood hematological malignancies receiving unrelated CBT, patients who received conditioning that omitted ATG had a faster platelet recovery, a comparable GVHD and TRM, a significantly lower relapse risk, and an improved long-term survival compared with those patients who received ATG in the conditioning.

BackgroundPosterior reversible encephalopathy syndrome (PRES) is an increasingly recognized serious complication of cyclosporine A (CSA) and tacrolimus (TAC) use in hematopoietic cell transplantation (HCT) recipients.ProcedureA retrospective study was carried out, including 84 cases of HCT for TM from January 2012 to January 2017. Eleven cases were diagnosed with PRES.ResultsThe cumulative incidence of PRES was 13.4% (95% confidence interval (CI) 9.7%‐17.2%). The median onset time of the symptoms was 63 [20, 143] days after transplantation. Lumber puncture found that CSF was normal. Univariate analysis showed that patients who received methylprednisolone (MP) (OR = 10.629 95% CI, 1.360‐83.071, P = 0.024), female patients (OR = 4.275, 95% CI, 1.154‐15.843, P = 0.032), patients who had severe hypertension (OR = 5.162, 95% CI, 1.042 to 25.559, P = 0.029) had significantly higher risks of PRES. Multivariate analysis showed that severe hypertension (hazard ratio [HR], 12.793; 95% CI, 1.477 to 110.813; P  = 0.021), and Pesaro class 3 (HR, 3.367; 95% CI, 1.210 to 9.368; P  =  0.020) were associated with PRES.ConclusionsThe severe hypertension is an independent risk factor for PRES post‐HCT in children with thalassemia major. Patients of Pesaro class 3 may benefit from optimum control of blood pressure post‐HCT for prophylaxis of PRES.

Aplastic anemia (AA) is a hematologic disease characterized by pancytopenia and hypocellular bone marrow, potentially leading to chronic anemia, hemorrhage, and infection. The China Aplastic Anemia Committee and British Committee for Standards in Haematology guidelines recommend hematopoietic stem-cell transplantation (HSCT) or immunosuppressive therapy (IST) comprising antithymocyte globulin (ATG) with cyclosporine (CsA) as initial treatment for AA patients. With limited epidemiological data on the clinical management of AA in Asia, a prospective cohort registry study involving 22 AA treatment centers in China was conducted to describe the disease characteristics of newly diagnosed AA patients and investigate real-world treatment patterns and patient outcomes. Of 340 AA patients, 72.9, 12.6, and 3.5% were receiving IST, traditional Chinese medicine, and HSCT, respectively, at baseline; only 22.2% of IST-treated patients received guideline-recommended ATG with CsA initially. Almost all patients received supportive care (95.6%) as blood transfusion (97.8%), antibiotics (63.7%), and/or hematopoietic growth factors (58.2%). Overall, 64.8% achieved a partial or complete response, and 0.9% experienced relapse. No new safety concerns were identified; serious adverse events were largely unrelated to the treatment regimen. These results demonstrate the need to identify and minimize treatment barriers to standardize and align AA management in China with treatment guideline recommendations and further improve patient outcomes.

Background: Thalidomide has been reported as a promising treatment for reducing transfusion volume in adults with β-thalassemia. However, the evidence about the safety and efficacy of thalidomide on children with transfusion dependent β-thalassemia (TDT) is scarce.Methods: Seventy-seven children with TDT treated with thalidomide at least for 6 months were included and retrospectively analyzed. Oral dose was started at 2.5 mg·kg-1·d-1. Blood volume for maintenance of hemoglobin above 90 g·L-1 compared with pre-treatment volume is the evaluation index for response.Results: After the sixth month treatment, 51/77 (66.2%) maintained Hb over 90 g·L-1 without transfusion. Adverse events were reported in 48 (63.2%) patients. Age, sex, genotype category, dosage, and transfusion interval before thalidomide treatment were not correlated to treatment response. The AUC was 0.806 for the HbF at the third month of treatment in predicting probability of major responders at the sixth month treatment. Based on Youden’s index algorithm in the ROC curve, 47.298 g·L-1 was the optimal cut-off value of the HbF at the third month of treatment in predicting major responders at the sixth month treatment, with sensitivity of 67.5% and specificity of 93.3%.Conclusions: The dose of thalidomide between 2.5 mg·kg-1·d-1 and 3.6 mg·kg-1·d-1 is effective in TDT children. Severe side effects are uncommon. HbF concentration of 47.298 g·L-1 at the third month is recommended as the predictor for further major responders.