Convergent somatic evolution commences in utero in a germline ribosomopathy.

Clonal tracking of cells using somatic mutations permits exploration of clonal dynamics in human disease. Here, we perform whole genome sequencing of 323 haematopoietic colonies from 10 individuals with the inherited ribosomopathy Shwachman-Diamond syndrome to reconstruct haematopoietic phylogenies. In ~30% of colonies, we identify mutually exclusive mutations in TP53, EIF6, RPL5, RPL22, PRPF8, plus chromosome 7 and 15 aberrations that increase SBDS and EFL1 gene dosage, respectively. Target gene mutations commence in utero, resulting in a profusion of clonal expansions, with only a few haematopoietic stem cell lineages (mean 8, range 1-24) contributing ~50% of haematopoietic colonies across 8 individuals (range 4-100% clonality) by young adulthood. Rapid clonal expansion during disease transformation is associated with biallelic TP53 mutations and increased mutation burden. Our study highlights how convergent somatic mutation of the p53-dependent nucleolar surveillance pathway offsets the deleterious effects of germline ribosomopathy but increases opportunity for TP53-mutated cancer evolution.

Role of allogeneic transplantation in chronic myelomonocytic leukemia: an international collaborative analysis.

To determine the survival benefit of allogeneic hematopoietic cell transplantation (allo-HCT) in chronic myelomonocytic leukemias (CMML), we assembled a retrospective cohort of CMML patients 18-70 years old diagnosed between 2000 and 2014 from an international CMML dataset (n = 730) and the EBMT registry (n = 384). The prognostic impact of allo-HCT was analyzed through univariable and multivariable time-dependent models and with a multistate model, accounting for age, sex, CMML prognostic scoring system (low or intermediate-1 grouped as lower-risk, intermediate-2 or high as higher-risk) at diagnosis, and AML transformation. In univariable analysis, lower-risk CMMLs had a 5-year overall survival (OS) of 20% with allo-HCT vs 42% without allo-HCT (P < .001). In higher-risk patients, 5-year OS was 27% with allo-HCT vs 15% without allo-HCT (P = .13). With multistate models, performing allo-HCT before AML transformation reduced OS in patients with lower-risk CMML, and a survival benefit was predicted for men with higher-risk CMML. In a multivariable analysis of lower-risk patients, performing allo-HCT before transformation to AML significantly increased the risk of death within 2 years of transplantation (hazard ratio [HR], 3.19; P < .001), with no significant change in long-term survival beyond this time point (HR, 0.98; P = .92). In higher-risk patients, allo-HCT significantly increased the risk of death in the first 2 years after transplant (HR 1.46; P = .01) but not beyond (HR, 0.60; P = .09). Performing allo-HCT before AML transformation decreases life expectancy in lower-risk patients but may be considered in higher-risk patients.

Iron chelation therapy in low risk myelodysplastic syndrome.

Anaemia is the commonest cytopenia seen in patients with myelodysplastic syndrome (MDS), and the majority of patients will require transfusion support at some point. Blood transfusions are rich in iron, which leads to the accumulation of body iron over time. It is accepted that this ultimately causes end organ damage and may impact on both morbidity and mortality. In addition, recent data has increased our interest in the subject with regard to the potential impact on stem cell transplant outcome and an anti-leukaemic effect of iron chelation therapy. There is still debate over which patients should receive iron chelation therapy, but the emergence of new diagnostic and prognostic markers in MDS may help decision making in the clinic setting.

Prospective study of rabbit antithymocyte globulin and cyclosporine for aplastic anemia from the EBMT Severe Aplastic Anaemia Working Party.

Rabbit antithymocyte globulin (rATG; thymoglobulin, Genzyme) in combination with cyclosporine, as first-line immunosuppressive therapy, was evaluated prospectively in a multicenter, European, phase 2 pilot study, in 35 patients with aplastic anemia. Results were compared with 105 age- and disease severity-matched patients from the European Blood and Marrow Transplant registry, treated with horse ATG (hATG; lymphoglobulin) and cyclosporine. The primary end point was response at 6 months. At 3 months, no patients had achieved a complete response to rATG. Partial response occurred in 11 (34%). At 6 months, complete response rate was 3% and partial response rate 37%. There were 10 deaths after rATG (28.5%) and 1 after subsequent HSCT. Infections were the main cause of death in 9 of 10 patients. The best response rate was 60% for rATG and 67% for hATG. For rATG, overall survival at 2 years was 68%, compared with 86% for hATG (P = .009). Transplant-free survival was 52% for rATG and 76% for hATG (P = .002). On multivariate analysis, rATG (hazard ratio = 3.9, P = .003) and age more than 37 years (hazard ratio = 4.7, P = .0008) were independent adverse risk factors for survival. This study was registered at www.clinicaltrials.gov as NCT00471848.

Cardiac iron overload in transfusion-dependent patients with myelodysplastic syndromes.

Transfusion-dependent myelodysplastic (MDS) patients are prone to iron overload. We evaluated 43 transfused MDS patients with T2* magnetic resonance imaging scans. 81% had liver and 16·8% cardiac iron overload. Liver R2* (1000/T2*), but not cardiac R2*, was correlated with number of units transfused (r=0·72, P<0·0001) and ferritin (r=0·53, P<0·0001). The area under the curve of a time-ferritin plot was found to be much greater in patients with cardiac iron loading (median 53·7x10(5) Megaunits vs. 12·2x10(5) Megaunits, P=0·002). HFE, HFE2, HAMP or SLC40A1 genotypes were not predictors of iron overload in these patients.

Myocardial iron loading by magnetic resonance imaging T2* in good prognostic myelodysplastic syndrome patients on long-term blood transfusions.

Magnetic resonance imaging (MRI) was used to quantify myocardial iron loading by T2* in 11 transfusion-dependent good prognostic myelodysplastic syndrome (MDS) patients. Myocardial T2*, left ventricular function and hepatic T2* were measured simultaneously. Patients had been on transfusion therapy for 13-123 months and had serum ferritin levels of 1109-6148 microg/l at the time of study. Five patients had not commenced iron chelation and had been transfused with a median of 63 red cell units and had a median serum ferritin level of 1490 microg/l. Six patients were on iron chelation and had been transfused with a median of 112 red cell units and had a median serum ferritin level of 4809 mug/l. Hepatic iron overload was mild in two, moderate in seven and severe in two patients. The median liver iron concentration was 5.9 mg/g dry weight in chelated patients and 9.5 mg/g in non-chelated patients (P = 0.17; not significant). Myocardial T2* indicated absent iron loading in 10/11 patients (91%; 95% confidence interval 62-98%) and borderline-normal in one patient. Left ventricular function was normal in all patients. No correlation was observed between increasing serum ferritin levels, hepatic iron overload and myocardial T2*. A long latent period relative to hepatic iron loading appears to predate the development of myocardial iron loading in transfusion-dependent MDS patients.

A pilot study of antithymocyte globulin (ATG) in the treatment of patients with 'low-risk' myelodysplasia.

We report 30 'low-risk' patients with myelodysplasia (MDS) (defined as < 10% bone marrow blasts) who were treated with antithymocyte globulin (ATG). In total, 20 patients were evaluable at the study end-point (response to treatment at 6 months). The diagnosis in these 20 patients was refractory anaemia (RA) in 13, RA with excess blasts in four, and RA with ringed sideroblasts in three. Median age was 54.5 years (range, 31-73 years). There were two cases of secondary MDS. The bone marrow was hypocellular in eight cases and cytogenetics were abnormal in four cases. All patients received lymphoglobuline (horse ATG; Sangstat, France) at a dose of 1.5 vials/10 kg/day for 5 d. The treatment was well tolerated. Three patients in the study died (disease progression, invasive aspergillosis and lung carcinoma respectively); 10 out of 20 evaluable patients (50%) responded to treatment and became transfusion independent; eight out of 13 (62%) patients with RA responded. The median duration of response was 15.5 months (2-42+ months) at the time of analysis.