Microenvironmental factors contribute to the immune dysfunction characterizing acute myeloid leukemia (AML). Indoleamine 2,3-dioxygenase 1 (IDO1) is an interferon (IFN)-γ-inducible enzyme that ...degrades tryptophan into kynurenine, which, in turn, inhibits effector T cells and promotes regulatory T-cell (Treg) differentiation. It is presently unknown whether childhood AML cells express IDO1 and whether IDO1 activity correlates with patient outcome. We investigated IDO1 expression and function in 37 children with newly diagnosed AML other than acute promyelocytic leukemia. Blast cells were cultured with exogenous IFN-γ for 24 hours, followed by the measurement of kynurenine production and tryptophan consumption. No constitutive expression of IDO1 protein was detected in blast cells from the 37 AML samples herein tested. Conversely, 19 out of 37 (51%) AML samples up-regulated functional IDO1 protein in response to IFN-γ. The inability to express IDO1 by the remaining 18 AML samples was not apparently due to a defective IFN-γ signaling circuitry, as suggested by the measurement of signal transducer and activator of transcription 3 (STAT3) phosphorylation. Co-immunoprecipitation assays indicated the occurrence of physical interactions between STAT3 and IDO1 in AML blasts. In line with this finding, STAT3 inhibitors abrogated IDO1 function in AML blasts. Interestingly, levels of IFN-γ were significantly higher in the bone marrow fluid of IDO-expressing compared with IDO-nonexpressing AMLs. In mixed tumor lymphocyte cultures (MTLC), IDO-expressing AML blasts blunted the ability of allogeneic naïve T cells to produce IFN-γ and promoted Treg differentiation. From a clinical perspective, the 8-year event-free survival was significantly worse in IDO-expressing children (16.4%, SE 9.8) as compared with IDO-nonexpressing ones (48.0%, SE 12.1; p=0.035). These data indicate that IDO1 expression by leukemia blasts negatively affects the prognosis of childhood AML. Moreover, they speak in favor of the hypothesis that IDO can be targeted, in adjunct to current chemotherapy approaches, to improve the clinical outcome of children with AML.
Cytomegalovirus retinitis (CMVR) following hematopoietic stem cell transplantation (HCT) for a primary immunodeficiency is a rare but highly morbid condition with potential irreversible consequences ...despite optimal antiviral pharmacotherapy. Viral‐specific T cells (VSTs) pose a promising and safe approach eradicating intractable viral disease. We describe the case of a 21‐month‐old male with Wiskott–Aldrich syndrome (WAS) and CMVR post HCT with sustained long‐term virologic and clinical response after CMV‐specific T‐cell therapy. This case highlights the need to consider VST as an adjunct upfront strategy in refractory CMVR and for routine ophthalmologic screening and surveillance in high‐risk patients post HCT.
Carbon-doped Mn5Ge3 thin films were grown using magnetron sputtering and reactive diffusion or non-diffusive reaction (NDR). The C content, the Curie temperature, and the resonance field difference ...between the hard and easy axis were measured for all the films, allowing linear relations between these three parameters to be quantitatively determined. Thanks to these functions, the measurement of a single of these parameters allows the two others to be known. The association of the sputtering technique to the NDR process appears as the best way for producing C-doped Mn5Ge3 thin films.
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Background: Allogeneic hematopoietic stem cell transplantation (HCT) offers the best chance of cure for children suffering from high-risk (HR) acute myeloid leukemia (AML). Over the last decade, a ...consensus between study groups has increasingly been developed on when and how to perform HCTs in these patients. However, the fate of children experiencing AML relapse after a first allogeneic HCT remains dismal. Methods: With the aim of analyzing the outcome of children that had documented AML relapse after a first allogeneic HCT, we performed a retrospective analysis collecting data from cooperative groups participating in the I-BFM consortium. A questionnaire was developed aiming to collect comparable data on children that did or did not proceed to a second allogeneic HCT. The questionnaire was sent to the national study coordinators and completed by the national groups from Australia, Austria, Belgium, Czech Republic, Denmark, Finland, Germany, Israel, Italy, the Netherlands, New Zealand, Norway, Poland, Sweden, and Switzerland. Overall survival (OS) and event-free survival (EFS) were estimated from the date of relapse after the first allograft or 2nd HCT to the date of an event or last follow-up. Probabilities of OS and EFS were calculated according to the Kaplan and Meier method. Results: 336 patients experiencing relapse between January 2005 and December 2016 were identified. 199 were male and 137 female. The median age was 8.6 years (range 0.4; 26.0). 178 (53%) were younger than 10 years and 138 (47%) 10 years or older. 156 (47.4%) had originally been transplanted in CR1, 148 in CR2 (45.0%), and 25 for refractory disease (7.6%). OS and EFS for the total group was 14% (standard error, SE=0.02) and 2% (SE=0.01) at 4 years respectively. Survival curves were superimposable for patients that had been primarily transplanted in CR 1 (OS 15%) and CR2 (OS 15%). Children originally transplanted in refractory disease had a significantly inferior OS of 4% (p=0.009) once relapsed after 1st HCT. OS was comparable for children presenting with either HR or SR molecular and cytogenetic features before HCT (p=0.85). A time interval between 1st HCT and relapse < 6 months was associated with poorer OS (7% vs 29% for patients relapsing > 6 months after the 1st allograft, p < 0.001).
Of note, only 123 (36.6%) children proceeded to a 2nd HCT. Importantly, the 4-year OS probability was 32% for children receiving a second transplant. This compared favorably with a 4-year OS of only 3% for those children who did not receive a 2nd HCT (p < 0.0001, Fig. A). Disease progression and failure to achieve another remission were the main reasons (58.6%) for not proceeding to a 2nd HSCT whereas poor performance status was an exclusion criterion for 11 %. Treatment failure after 2nd HCT was disease-related in 65% of patients; transplant-related mortality (TRM) accounted for 21% of deaths. For the remaining 14% of children, data were not attributable.
Graft source (bone marrow vs. peripheral blood stem cells/ cord blood, 49% versus 23%, p= 0.036, Fig. B) and donor type (matched sibling/ family donor vs. matched unrelated donor, 61% versus 14%, p=0.04, Fig. C) influenced patient's outcome after the 2nd allograft. Children experiencing any type of graft-versus-host disease (GVHD) had a better, although not statistically significant, probability of OS as compared to those who did not develop GVHD (47 % vs. 25%).
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Sauer:Neovii: Research Funding.
Summary
Treosulfan‐based conditioning is increasingly employed in paediatric haematopoietic stem cell transplantation (HSCT). Data on treosulfan pharmacokinetics in children are scarce, and the ...relationship between treosulfan exposure, toxicity and clinical outcome is unresolved. In this multicentre prospective observational study, we studied treosulfan pharmacokinetics and the drug's relationship with regimen‐related toxicity and early clinical outcome in 77 paediatric patients. Treosulfan dose was 30 g/m2, administered over 3 consecutive days in infants <1 year old (n = 12) and 42 g/m2 in children ≥1 year old (n = 65). Mean day 1 treosulfan exposure was 1744 ± 795 mg*h/l (10 g/m2) and 1561 ± 511 mg*h/l (14 g/m2), with an inter‐individual variability of 56 and 33% in the respective groups. High treosulfan exposure (>1650 mg*h/l) was associated with an increased risk of mucosal Odds ratio (OR) 4·40; 95% confidence interval (CI) 1·19–16·28, P = 0·026 and skin toxicity (OR 4·51; 95% CI 1·07–18·93, P = 0·040). No correlation was found between treosulfan exposure and the early clinical outcome parameters: engraftment, acute graft‐versus‐host disease and donor chimerism. Our study provides the first evidence in a large cohort of paediatric patients of high variability in treosulfan pharmacokinetics and an association between treosulfan exposure and early toxicity. Ongoing studies will reveal whether treosulfan exposure is related to long‐term disease‐specific outcome and late treatment‐related toxicity.
Allogeneic hematopoietic stem cell transplantation is an effective therapy for high-risk leukemias. In children, graft manipulation based on the selective removal of αβT cells and B cells has been ...shown to reduce the risk of acute and chronic graft-
versus
-host disease, thus allowing the use of haploidentical donors which expands the population of recipients in whom allogeneic hematopoietic stem cell transplantation can be used. Leukemic relapse, however, remains a challenge. T cells expressing chimeric antigen receptors can potently eliminate leukemia, including those in the central nervous system. We hypothesized that by engineering the donor αβT cells that are removed from the graft by genome editing to express a CD19-specific chimeric antigen receptor, while simultaneously inactivating the T-cell receptor, we could create a therapy that enhances the anti-leukemic efficacy of the stem cell transplant without increasing the risk of graft-
versus
-host disease. Using genome editing with Cas9 ribonucleoprotein and adeno-associated virus serotype 6, we integrated a CD19-specific chimeric antigen receptor inframe into the TRAC locus. More than 90% of cells lost T-cell receptor expression, while >75% expressed the chimeric antigen receptor. The initial product was further purified with less than 0.05% T-cell receptorpositive cells remaining.
In vitro
, the chimeric antigen receptor T cells efficiently eliminated target cells and produced high cytokine levels when challenged with CD19
+
leukemia cells.
In vivo
, the gene-modified T cells eliminated leukemia without causing graft-
versus
-host disease in a xenograft model. Gene editing was highly specific with no evidence of off-target effects. These data support the concept that the addition of αβ T-cell-derived, genome-edited T cells expressing CD19-specific chimeric antigen receptors could enhance the anti-leukemic efficacy of αβT-celldepleted haploidentical hematopoietic stem cell transplantation without increasing the risk of graft-
versus
-host disease.
Late-Onset Neonatal Sepsis (LOS) is a rare condition, involving widespread infection, immune disruption, organ dysfunction, and often death. Because exposure to pathogens is not completely ...preventable, identifying susceptibility factors is critical to characterizing the pathophysiology and developing interventions. Prior studies demonstrated both genetics and infant sex influence susceptibility. Our study was designed to identify LOS associated genetic variants.
We performed an exploratory genome wide association study (GWAS) with 224 LOS cases and 273 controls from six European countries. LOS was defined as sepsis presenting from 3 to 90 days of age; diagnosis was established by clinical criteria consensus guidelines. We tested for association with both autosomal and X-chromosome variants in the total sample and in sex-stratified analyses.
In total, 71 SNPs associated with neonatal sepsis at p < 1 × 10
in at least one analysis. Most importantly, sex-stratified analyses revealed associations with multiple SNPs (28 in males and 16 in females), but no variants from single-sex analyses associated with sepsis in the other sex. Pathway analyses showed NOTCH signaling is over-represented among genes linked to these SNPS.
Our results indicate genetic susceptibility to LOS is sexually dimorphic and corroborate that NOTCH signaling plays a role in determining risk.
Genes associate with late onset neonatal sepsis. Notch pathway genes are overrepresented in associations with sepsis. Genes associating with sepsis do not overlap between males and females. Sexual dimorphism can lead to sex specific treatment of sepsis.
Juvenile myelomonocytic leukemia (JMML) is a deadly pediatric leukemia with limited treatment options and poor clinical outcomes. Effective targeted treatment strategies are an urgent unmet need. To ...improve outcomes for this pediatric patient population, we examined the structure of the DNA comprising the genomes of leukemic cells from five JMML patients and compared these to DNA structures from healthy controls. These data allowed us to identify structural features that were unique to the JMML patient DNA. Identification of these JMML-specific changes could guide development of targeted drugs to effectively treat this devastating malignancy. Our work provides a rich resource for additional investigations aimed at identifying and testing strategies designed to treat JMML. Juvenile myelomonocytic leukemia (JMML) is a deadly pediatric leukemia driven by RAS pathway mutations, of which >35% are gain-of-function in PTPN11. Although DNA hypermethylation portends severe clinical phenotypes, the landscape of histone modifications and chromatin profiles in JMML patient cells have not been explored. Using global mass cytometry, Epigenetic Time of Flight (EpiTOF), we analyzed hematopoietic stem and progenitor cells (HSPCs) from five JMML patients with PTPN11 mutations. These data revealed statistically significant changes in histone methylation, phosphorylation, and acetylation marks that were unique to JMML HSPCs when compared with healthy controls. Consistent with these data, assay for transposase-accessible chromatin with sequencing (ATAC-seq) analysis revealed significant alterations in chromatin profiles at loci encoding post-translational modification enzymes, strongly suggesting their mis-regulated expression. Collectively, this study reveals histone modification pathways as an additional epigenetic abnormality in JMML patient HSPCs, thereby uncovering a new family of potential druggable targets for the treatment of JMML.
We present a fully detailed and highly performing implementation of the Linear Method (Toulouse and Umrigar, 2007) to optimize Jastrow–Feenberg and Backflow Correlations in many-body wave-functions, ...which are widely used in condensed matter physics. We show that it is possible to implement such optimization scheme performing analytical derivatives of the wave-function with respect to the variational parameters achieving the best possible complexity O(N3) in the number of particles N.
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