Key Points• Germline GATA2 mutations account for 15% of advanced and 7% of all primary pediatric MDS and do not influence overall survival. • The majority (72%) of adolescents with MDS and monosomy 7 carry an underlying GATA2 deficiency.Germline GATA2 mutations cause cellular deficiencies with high propensity for myeloid disease. We investigated 426 children and adolescents with primary myelodysplastic syndrome (MDS) and 82 cases with secondary MDS enrolled in 2 consecutive prospective studies of the European Working Group of MDS in Childhood (EWOG-MDS) conducted in Germany over a period of 15 years. Germline GATA2 mutations accounted for 15% of advanced and 7% of all primary MDS cases, but were absent in children with MDS secondary to therapy or acquired aplastic anemia. Mutation carriers were older at diagnosis and more likely to present with monosomy 7 and advanced disease compared with wild-type cases. For stratified analysis according to karyotype, 108 additional primary MDS patients registered with EWOG-MDS were studied. Overall, we identified 57 MDS patients with germline GATA2 mutations. GATA2 mutations were highly prevalent among patients with monosomy 7 (37%, all ages) reaching its peak in adolescence (72% of adolescents with monosomy 7). Unexpectedly, monocytosis was more frequent in GATA2-mutated patients. However, when adjusted for the selection bias from monosomy 7, mutational status had no effect on the hematologic phenotype. Finally, overall survival and outcome of hematopoietic stem cell transplantation (HSCT) were not influenced by mutational status. This study identifies GATA2 mutations as the most common germline defect predisposing to pediatric MDS with a very high prevalence in adolescents with monosomy 7. GATA2 mutations do not confer poor prognosis in childhood MDS. However, the high risk for progression to advanced disease must guide decision-making toward timely

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A total of 156 patients (age range 1.3-18.0 years, median 13.2 years; 91 (58.3%) male) with newly diagnosed CML (N = 146 chronic phase (CML-CP), N = 3 accelerated phase (CML-AP), N = 7 blastic phase (CML-BP)) received imatinib up-front (300, 400, 500 mg/m, respectively) within a prospective phase III trial. Therapy response, progression-free survival, causes of treatment failure, and side effects were analyzed in 148 children and adolescents with complete data. Event-free survival rate by 18 months for patients in CML-CP (median follow-up time 25 months, range: 1-120) was 97% (95% CI, 94.2-99.9%). According to the 2006 ELN-criteria complete hematologic response by month 3, complete cytogenetic response (CCyR) by month 12, and major molecular response (MMR) by month 18 were achieved in 98, 63, and 59% of the patients, respectively. By month 36, 86% of the patients achieved CCyR and 74% achieved MMR. Thirty-eight patients (27%) experienced imatinib failure because of unsatisfactory response or intolerance (N = 9). In all, 28/148 patients (19%) underwent stem cell transplantation (SCT). In the SCT sub-cohort 2/23 patients diagnosed in CML-CP, 0/1 in CML-AP, and 2/4 in CML-BP, respectively, died of relapse (N = 3) or SCT-related complications (N = 2). This large pediatric trial extends and confirms data from smaller series that first-line imatinib in children is highly effective.

Chronic Granulomatous Disease (CGD) is a primary immunodeficiency resulting in life-threatening infections and inflammatory complications. Allogeneic hematopoietic cell transplantation (allo-HCT) can cure patients, but indication to transplant remains controversial. We performed a retrospective multicentre study on 712 patients with CGD undergoing allo-HCT transplanted in EBMT centres between 1993 and 2018. We studied 635 children (aged < 18 years) and 77 adults. Median follow-up was 45 months. Median age at transplant was 7 years (range: 0.1-48.6). Kaplan-Meier estimates of OS and EFS at 3 years were 85.7% (95% CI, 82.8-88.5) and 75.8% (95% CI, 72.3-79.3), respectively. On MVA, older age was associated with reduced survival (HR= 1.69, p= 0.0001) and increased chronic GVHD (HR 1.35, p=0.01). Nevertheless OS and EFS at 3 years for patients ≥ 18 years was 76% (95%CI, 66-86) and 69% (95%CI, 57-80), respectively. Use of one antigen-mismatched donors was associated with reduced OS (HR= 2.29, p= 0.01) and EFS (HR 2.37, p=0.001). No significant difference was found in OS, but a significantly reduced EFS (HR 3.69 p=0.001), in the small group who received a transplant from a donor with more than one antigen-mismatch. Choice of conditioning regimen did not influence OS or EFS. In conclusion we report an excellent outcome after allo-HCT in CGD, with low incidence of graft failure and mortality in all ages. Older patients and recipients of one antigen-mismatched grafts have a less favourable outcome. Transplant should be strongly considered at a younger age and particularly in the presence of a well-matched donor.

Key Points• Treosulfan, a low-toxicity alkylating agent, can be used effectively as part of conditioning for HSCT in children with CGD.• Long-term follow-up is required to ascertain effects, particularly on gonadal function and compare with other regimens.Chronic granulomatous disease (CGD) can be cured by allogeneic hemopoietic stem cell transplantation (HSCT). Complications include graft failure, graft-versus-host disease (GVHD), infection, and transplant-related mortality; therefore, reduced-intensity conditioning regimens are being used to improve outcomes. In this retrospective study, the aim was to determine the outcome of treosulfan-based conditioning in HSCT for pediatric patients with CGD. (IQR, and 16 (IQR, 13-50) days. At a median follow-up of 34 months (IQR, 13-102 months), the overall survival was 91.4%, and event-free survival was 81.4%. The cumulative incidence of acute grade III-IV GVHD was 12%. Nine patients developed chronic GVHD. When split cell chimerism was available, 95% or more myeloid donor chimerism was documented in 80% of surviving patients. Secondary graft failure occurred in 12% of patients. Treosulfancontaining conditioning regimens can be used safely in HSCT for children with CGD and high-risk clinical features, achieving excellent survival with high myeloid chimerism. Further studies are needed to compare with other regimens and evaluate the longterm outcome, particularly on fertility. (Blood. 2016;128(3):440-448)