Publications by authors named "Robert Chiesa"

55 Publications

Outcome of Non-hematological Autoimmunity After Hematopoietic Cell Transplantation in Children with Primary Immunodeficiency.

J Clin Immunol 2021 Jan 3;41(1):171-184. Epub 2020 Nov 3.

Children's Haematopoietic Stem Cell Transplant Unit, Great North Children's Hospital, Newcastle upon Tyne Hospital NHS Foundation Trust, Clinical Resource Building, Floor 4, Block 2, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK.

Purpose: Knowledge of post-hematopoietic cell transplantation (HCT) non-hematological autoimmune disease (AD) is far from satisfactory.

Method: This multicenter retrospective study focuses on incidence, risk factors, and outcomes of post-HCT AD in 596 children with primary immunodeficiency (PID) who were transplanted from 2009 to 2018.

Results: The indications of HCT were severe combined immunodeficiency (SCID, n = 158, 27%) and non-SCID PID (n = 438, 73%). The median age at HCT was 2.3 years (range, 0.04 to 18.3 years). The 5-year overall survival for the entire cohort was 79% (95% cumulative incidence (CIN), 74-83%). The median follow-up of surviving patients was 4.3 years (0.08 to 14.7 years). The CIN of post-HCT AD was 3% (2-5%) at 1 year post-HCT, 7% (5-11%) at 5 years post-HCT, and 11% (7-17%) at 8 years post-HCT. The median onset of post-HCT AD was 2.2 years (0.12 to 9.6 years). Autoimmune thyroid disorder (n = 19, 62%) was the most common post-HCT AD, followed by neuromuscular disorders (n = 7, 22%) and rheumatological manifestations (n = 5, 16%). All patients but one required treatment for post-HCT AD. After multivariate analysis, age at transplant (p = 0.01) and T cell-depleted graft (p < 0.001) were significant predictors of post-HCT AD. None of the T cell-depleted graft recipients developed post-HCT AD. Patients with a lower CD3+ count at 6 months post-HCT had a significant higher incidence of post-HCT AD compared to disease controls. Graft-versus-host disease, viral infection, and donor chimerism had no association with post-HCT AD.

Conclusion: Post-HCT AD occurred in 11% at 8 years post-HCT and its occurrence was associated with older age at HCT and unmanipulated graft.
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http://dx.doi.org/10.1007/s10875-020-00895-3DOI Listing
January 2021

Pathobiologic Mechanisms of Neurodegeneration in Osteopetrosis Derived From Structural and Functional Analysis of 14 ClC-7 Mutants.

J Bone Miner Res 2020 Oct 30. Epub 2020 Oct 30.

Consiglio Nazionale delle Ricerche, Istituto di Biofisica (CNR-IBF), Dulbecco Telethon Laboratory, Genoa, Italy.

ClC-7 is a chloride-proton antiporter of the CLC protein family. In complex with its accessory protein Ostm-1, ClC-7 localizes to lysosomes and to the osteoclasts' ruffled border, where it plays a critical role in acidifying the resorption lacuna during bone resorption. Gene inactivation in mice causes severe osteopetrosis, neurodegeneration, and lysosomal storage disease. Mutations in the human CLCN7 gene are associated with diverse forms of osteopetrosis. The functional evaluation of ClC-7 variants might be informative with respect to their pathogenicity, but the cellular localization of the protein hampers this analysis. Here we investigated the functional effects of 13 CLCN7 mutations identified in 13 new patients with severe or mild osteopetrosis and a known ADO2 mutation. We mapped the mutated amino acid residues in the homology model of ClC-7 protein, assessed the lysosomal colocalization of ClC-7 mutants and Ostm1 through confocal microscopy, and performed patch-clamp recordings on plasma-membrane-targeted mutant ClC-7. Finally, we analyzed these results together with the patients' clinical features and suggested a correlation between the lack of ClC-7/Ostm1 in lysosomes and severe neurodegeneration. © 2020 American Society for Bone and Mineral Research (ASBMR).
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http://dx.doi.org/10.1002/jbmr.4200DOI Listing
October 2020

Haematopoietic Stem Cell Transplantation for DNA Ligase 1 Deficiency.

J Clin Immunol 2021 Jan 6;41(1):238-242. Epub 2020 Oct 6.

Department of Bone Marrow Transplantation, Great Ormond Street Hospital for Children NHS Trust, London, UK.

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http://dx.doi.org/10.1007/s10875-020-00871-xDOI Listing
January 2021

Cellular Therapies in Chronic Granulomatous Disease.

Front Pediatr 2020 26;8:327. Epub 2020 Jun 26.

Department of Bone Marrow Transplantation, Great Ormond Street Hospital for Sick Children, London, United Kingdom.

Allogeneic hematopoietic stem cell transplantation (HSCT) has become the main curative treatment in patients with chronic granulomatous disease (CGD). CGD is caused by inherited defects of the phagolysomal NADPH-oxidase, leading to a lifelong propensity for invasive infections and granulomatous inflammation. After successful allogeneic HSCT, chronic infections and inflammation resolve and quality-of-life improves. Favorable long-term outcome after HSCT is dependent on the prevention of primary and secondary graft failure (GF), including falling myeloid donor chimerism (DC) below 10 %, and chronic graft-vs.-host-disease (cGVHD). The risk of GF and GvHD increases with the use of HLA-incompatible donors and this may outweigh the benefits of HSCT, mainly in patients with severe co-morbidities and in asymptomatic patients with residual NADPH-oxidase function. Seventeen scientific papers have reported on a total of 386 CGD-patients treated by HSCT with HLA-matched family/sibling (MFD/MSD), 9/10-/10/10-matched-unrelated volunteer (MUD) and cord blood donors. The median OS/EFS-rate of these 17 studies was 91 and 82%, respectively. The median rates of GF, cGVHD and autoimmune diseases were 14, 10, and 12%, respectively. Results after MFD/MSD and 10/10-MUD-transplants were rather similar, but outcome in adults with significant co-morbidities and after transplants with 9/10 HLA-MUD were less successful, mainly due to increased GF and chronic GVHD. Transplantation protocols using T-cell depleted haploidentical donors with post-transplant cyclophosphamide or TCR-alpha/beta depletion have recently reported promising results. Autologous gene-therapy after lentiviral transduction of HSC achieved OS/EFS-rates of 78/67%, respectively. Careful retrospective and prospective studies are mandatory to ascertain the most effective cellular therapies in patients with CGD.
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http://dx.doi.org/10.3389/fped.2020.00327DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7333593PMC
June 2020

Hematopoietic cell transplantation in chronic granulomatous disease: a study of 712 children and adults.

Blood 2020 Sep;136(10):1201-1211

Department of Paediatric Immunology, Great North Children's Hospital, Newcastle upon Tyne, United Kingdom.

Chronic granulomatous disease (CGD) is a primary immunodeficiency resulting in life-threatening infections and inflammatory complications. Allogeneic hematopoietic cell transplantation (allo-HCT) can cure the disease, but the indication to transplant remains controversial. We performed a retrospective multicenter study of 712 patients with CGD who underwent allo-HCT transplantation from March 1993 through December 2018. We studied 635 children (aged <18 years) and 77 adults. Median follow-up was 45 months. Median age at transplantation was 7 years (range, 0.1-48.6). Kaplan-Meier estimates of overall survival (OS) and event-free survival (EFS) at 3 years were 85.7% and 75.8%, respectively. In multivariate analysis, older age was associated with reduced survival and increased chronic graft-versus-host disease. Nevertheless, OS and EFS at 3 years for patients ≥18 years were 76% and 69%, respectively. Use of 1-antigen-mismatched donors was associated with reduced OS and EFS . No significant difference was found in OS, but a significantly reduced EFS was noted in the small group of patients who received a transplant from a donor with a >1 antigen mismatch. Choice of conditioning regimen did not influence OS or EFS. In summary, 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 1-antigen-mismatched grafts had a less favorable outcome. Transplantation should be strongly considered at a younger age and particularly in the presence of a well-matched donor.
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http://dx.doi.org/10.1182/blood.2020005590DOI Listing
September 2020

New insights into risk factors for transplant-associated thrombotic microangiopathy in pediatric HSCT.

Blood Adv 2020 06;4(11):2418-2429

Department of Blood and Marrow Transplantation, Great Ormond Street (GOS) Hospital for Children NHS Foundation Trust, University College London GOS Institute of Child Health, and NIHR GOSH BRC, London, United Kingdom.

This study aimed to identify a risk profile for development of transplant-associated thrombotic microangiopathy (TA-TMA) in children undergoing hematopoietic stem cell transplantation (HSCT). Between 2013 and 2016, 439 children underwent 474 HSCTs at 2 supraregional United Kingdom centers. At a median of 153 days post-HSCT, TA-TMA occurred among 25 of 441 evaluable cases (5.6%) with no evidence of center variation. Sex, underlying disease, intensity of the conditioning, total body irradiation-based conditioning, the use of calcineurin inhibitors, venoocclusive disease, and viral reactivation did not influence the development of TA-TMA. Donor type: matched sibling donor/matched family donor vs matched unrelated donor vs mismatched unrelated donor/haplo-HSCT, showed a trend toward the development of TA-TMA in 1.8% vs 6.1% vs 8.3%, respectively. Presence of active comorbidity was associated with an increased risk for TA-TMA; 13% vs 3.7% in the absence of comorbidity. The risk of TA-TMA was threefold higher among patients who received >1 transplant. TA-TMA rates were significantly higher among patients with acute graft-versus-host disease (aGVHD) grades III to IV vs aGVHD grade 0 to II. On multivariate analysis, the presence of active comorbidity, >1 transplant, aGVHD grade III to IV were risk factors for TA-TMA (odds ratio [OR]: 5.1, 5.2, and 26.9; respectively), whereas the use of cyclosporine A/tacrolimus-based GVHD prophylaxis was not a risk factor for TA-TMA (OR: 0.3). Active comorbidity, subsequent transplant, and aGVHD grades III to IV were significant risk factors for TA-TMA. TA-TMA might represent a form of a vascular GVHD, and therefore, continuing control of aGVHD is important to prevent worsening of TA-TMA associated with GVHD.
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http://dx.doi.org/10.1182/bloodadvances.2019001315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284098PMC
June 2020

Modelling of neutrophil dynamics in children receiving busulfan or treosulfan for haematopoietic stem cell transplant conditioning.

Br J Clin Pharmacol 2020 08 3;86(8):1537-1549. Epub 2020 Mar 3.

Department of Pharmacy, Great Ormond Street Hospital for Children, London, UK.

Aims: Busulfan and treosulfan are cytotoxic agents used in the conditioning regime prior to paediatric haematopoietic stem cell transplantation (HSCT). These agents cause suppression of myeloid cells leaving patients severely immunocompromised in the early post-HSCT period. The main objectives were: (i) to establish a mechanistic pharmacokinetic-pharmacodynamic (PKPD) model for the treatment and engraftment effects on neutrophil counts comparing busulfan and treosulfan-based conditioning, and (ii) to explore current dosing schedules with respect to time to HSCT.

Methods: Data on 126 patients, 72 receiving busulfan (7 months-18 years, 5.1-47.0 kg) and 54 treosulfan (4 months-17 years, 3.8-35.8 kg), were collected. In total, 8935 neutrophil count observations were recorded during the study period in addition to drug concentrations to develop a mechanistic PKPD model. Absolute neutrophil count profiles were modelled semimechanistically, accounting for transplant effects and differing set points pre- and post-transplant.

Results: PK were best described by 2-compartment models for both drugs. The Friberg semimechanistic neutropenia model was applied with a linear model for busulfan and a maximum efficacy model for treosulfan describing drug effects at various stages of neutrophil maturation. System parameters were consistent across both drugs. The HSCT was represented by an amount of progenitor cells enhancing the neutrophils' proliferation and maturation compartments. Alemtuzumab was found to enhance the proliferative rate under which the absolute neutrophil count begin to grow after HSCT.

Conclusion: A semimechanistic PKPD model linking exposure to either busulfan or treosulfan to the neutrophil reconstitution dynamics was successfully built. Alemtuzumab coadministration enhanced the neutrophil proliferative rate after HSCT. Treosulfan administration was suggested to be delayed with respect to time to HSCT, leaving less time between the end of the administration and stem cell infusion.
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http://dx.doi.org/10.1111/bcp.14260DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7373705PMC
August 2020

Proposed Therapeutic Range of Treosulfan in Reduced Toxicity Pediatric Allogeneic Hematopoietic Stem Cell Transplant Conditioning: Results From a Prospective Trial.

Clin Pharmacol Ther 2020 Aug 14;108(2):264-273. Epub 2019 Dec 14.

Bone Marrow Transplantation Department, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.

Treosulfan is given off-label in pediatric allogeneic hematopoietic stem cell transplant. This study investigated treosulfan's pharmacokinetics (PKs), efficacy, and safety in a prospective trial. Pediatric patients (n = 87) receiving treosulfan-fludarabine conditioning were followed for at least 1 year posttransplant. PKs were described with a two-compartment model. During follow-up, 11 of 87 patients died and 12 of 87 patients had low engraftment (≤ 20% myeloid chimerism). For each increase in treosulfan area under the curve from zero to infinity (AUC ) of 1,000 mg hour/L the hazard ratio (95% confidence interval) for mortality increase was 1.46 (1.23-1.74), and the hazard ratio for low engraftment was 0.61 (0.36-1.04). A cumulative AUC of 4,800 mg hour/L maximized the probability of success (> 20% engraftment and no mortality) at 82%. Probability of success with AUC between 80% and 125% of this target were 78% and 79%. Measuring PK at the first dose and individualizing the third dose may be required in nonmalignant disease.
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http://dx.doi.org/10.1002/cpt.1715DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7484914PMC
August 2020

Delaying haematopoietic stem cell transplantation in children with viral respiratory infections reduces transplant-related mortality.

Br J Haematol 2020 02 30;188(4):560-569. Epub 2019 Sep 30.

Bone Marrow Transplantation Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.

Viral respiratory infections (VRIs) contribute to the morbidity and transplant-related mortality (TRM) after allogeneic haematopoietic stem cell transplantation (HSCT) and strategies to prevent and treat VRIs are warranted. We monitored VRIs before and after transplant in children undergoing allogeneic HSCT with nasopharyngeal aspirates (NPA) and assessed the impact on clinical outcome. Between 2007 and 2017, 585 children underwent 620 allogeneic HSCT procedures. Out of 75 patients with a positive NPA screen (12%), transplant was delayed in 25 cases (33%), while 53 children started conditioning with a VRI. Patients undergoing HSCT with a positive NPA screen had a significantly lower overall survival (54% vs. 79%) and increased TRM (26% vs. 7%) compared to patients with a negative NPA. Patients with a positive NPA who delayed transplant and cleared the virus before conditioning had improved overall survival (90%) and lower TRM (5%). Pre-HSCT positive NPA was the only significant risk factor for progression to a lower respiratory tract infection and was a major risk factor for TRM. Transplant delay, whenever feasible, in case of a positive NPA screen for VRIs can positively impact on survival of children undergoing HSCT.
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http://dx.doi.org/10.1111/bjh.16216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7161889PMC
February 2020

Enhanced CAR T cell expansion and prolonged persistence in pediatric patients with ALL treated with a low-affinity CD19 CAR.

Nat Med 2019 09 2;25(9):1408-1414. Epub 2019 Sep 2.

Molecular and Cellular Immunology Section, UCL Great Ormond Street Institute of Child Health, London, UK.

Chimeric antigen receptor (CAR)-modified T cells targeting CD19 demonstrate unparalleled responses in relapsed/refractory acute lymphoblastic leukemia (ALL), but toxicity, including cytokine-release syndrome (CRS) and neurotoxicity, limits broader application. Moreover, 40-60% of patients relapse owing to poor CAR T cell persistence or emergence of CD19 clones. Some factors, including the choice of single-chain spacer and extracellular and costimulatory domains, have a profound effect on CAR T cell function and persistence. However, little is known about the impact of CAR binding affinity. There is evidence of a ceiling above which increased immunoreceptor affinity may adversely affect T cell responses. We generated a novel CD19 CAR (CAT) with a lower affinity than FMC63, the high-affinity binder used in many clinical studies. CAT CAR T cells showed increased proliferation and cytotoxicity in vitro and had enhanced proliferative and in vivo antitumor activity compared with FMC63 CAR T cells. In a clinical study (CARPALL, NCT02443831 ), 12/14 patients with relapsed/refractory pediatric B cell acute lymphoblastic leukemia treated with CAT CAR T cells achieved molecular remission. Persistence was demonstrated in 11 of 14 patients at last follow-up, with enhanced CAR T cell expansion compared with published data. Toxicity was low, with no severe CRS. One-year overall and event-free survival were 63% and 46%, respectively.
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http://dx.doi.org/10.1038/s41591-019-0549-5DOI Listing
September 2019

Current status of umbilical cord blood transplantation in children.

Br J Haematol 2020 09 13;190(5):650-683. Epub 2019 Aug 13.

Bone Marrow Transplantation, Great Ormond Street Hospital, London, UK.

The first umbilical cord blood (UCB) transplantation was performed 30 years ago. UCB transplantation (UCBT) is now widely used in children with malignant and non-malignant disorders who lack a matched family donor. UCBT affords a lower incidence of graft-versus-host disease compared to alternative stem cell sources, but also presents a slower immune recovery and a high risk of infections if serotherapy is not omitted or targeted within the conditioning regimen. The selection of UCB units with high cell content and good human leucocyte antigen match is essential to improve the outcome. Techniques, such as double UCBT, ex vivo stem cell expansion and intra-bone injection of UCB, have improved cord blood engraftment, but clinical benefit remains to be demonstrated. Cell therapies derived from UCB are under evaluation as potential novel strategies to reduce relapse and viral infections following transplantation. In recent years, improvements within haploidentical transplantation have reduced the overall use of UCBT as an alternative stem cell source; however, each may have its relative merits and disadvantages and tailored use of these alternative stem cell sources may be the optimal approach.
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http://dx.doi.org/10.1111/bjh.16107DOI Listing
September 2020

New graft manipulation strategies improve the outcome of mismatched stem cell transplantation in children with primary immunodeficiencies.

J Allergy Clin Immunol 2019 07 4;144(1):280-293. Epub 2019 Feb 4.

Molecular and Cellular Immunology Unit, University College London (UCL) Great Ormond Street Institute of Child Health, London, United Kingdom; Blood and Bone Marrow Transplant Unit, Great Ormond Street Hospital, London, United Kingdom.

Background: Mismatched stem cell transplantation is associated with a high risk of graft loss, graft-versus-host disease (GvHD), and transplant-related mortality. Alternative graft manipulation strategies have been used over the last 11 years to reduce these risks.

Objective: We investigated the outcome of using different graft manipulation strategies among children with primary immunodeficiencies.

Methods: Between 2006 and 2017, 147 patients with primary immunodeficiencies received 155 mismatched grafts: 30 T-cell receptor (TCR) αβ/CD19-depleted grafts, 43 cord blood (CB) grafts (72% with no serotherapy), 17 CD34 selection with T-cell add-back grafts, and 65 unmanipulated grafts.

Results: The estimated 8-year survival of the entire cohort was 79%, transplant-related mortality was 21.7%, and the graft failure rate was 6.7%. Posttransplantation viral reactivation, grade II to IV acute graft-versus-host disease (aGvHD), and chronic graft-versus-host disease (cGvHD) complicated 49.6%, 35%, and 15% of transplantations, respectively. Use of TCRαβ/CD19 depletion was associated with a significantly lower incidence of grade II to IV aGvHD (11.5%) and cGvHD (0%), although with a greater incidence of viral reactivation (70%) in comparison with other grafts. T-cell immune reconstitution was robust among CB transplants, although with a high incidence (56.7%) of grade II to IV aGvHD. Stable full donor engraftment was significantly greater at 80% among TCRαβ/CD19-depleted and CB transplants versus 40% to 60% among the other groups.

Conclusions: Rapidly accessible CB and haploidentical grafts are suitable alternatives for patients with no HLA-matched donor. Cord transplantation without serotherapy and TCRαβ/CD19-depleted grafts produced comparable survival rates of around 80%, although with a high rate of aGvHD with the former and a high risk of viral reactivation with the latter that need to be addressed.
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http://dx.doi.org/10.1016/j.jaci.2019.01.030DOI Listing
July 2019

Adoptive T Cell Therapy Strategies for Viral Infections in Patients Receiving Haematopoietic Stem Cell Transplantation.

Cells 2019 01 14;8(1). Epub 2019 Jan 14.

Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.

Adverse outcomes following virus-associated disease in patients receiving allogeneic haematopoietic stem cell transplantation (HSCT) have encouraged strategies to control viral reactivation in immunosuppressed patients. However, despite timely treatment with antiviral medication, some viral infections remain refractory to treatment, which hampers outcomes after HSCT, and are responsible for a high proportion of transplant-related morbidity and mortality. Adoptive transfer of donor-derived lymphocytes aims to improve cellular immunity and to prevent or treat viral diseases after HSCT. Early reports described the feasibility of transferring nonspecific lymphocytes from donors, which led to the development of cell therapy approaches based on virus-specific T cells, allowing a targeted treatment of infections, while limiting adverse events such as graft versus host disease (GvHD). Both expansion and direct selection techniques have yielded comparable results in terms of efficacy (around 70⁻80%), but efficacy is difficult to predict for individual cases. Generating bespoke products for each donor⁻recipient pair can be expensive, and there remains the major obstacle of generating products from seronegative or poorly responsive donors. More recent studies have focused on the feasibility of collecting and infusing partially matched third-party virus-specific T cells, reporting response rates of 60⁻70%. Future development of this approach will involve the broadening of applicability to multiple viruses, the optimization and cost-control of manufacturing, larger multicentred efficacy trials, and finally the creation of cell banks that can provide prompt access to virus-specific cellular product. The aim of this review is to summarise present knowledge on adoptive T cell manufacturing, efficacy and potential future developments.
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http://dx.doi.org/10.3390/cells8010047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6356262PMC
January 2019

Correction to: Clinical Pharmacokinetics and Dose Recommendations for Posaconazole in Infants and Children.

Clin Pharmacokinet 2019 Jan;58(1):141

Infection, Inflammation, Immunity Section, Room 661, UCL Great Ormond Street Institute of Child Health, University College London, London, WC1N 1EH, UK.

However, the Original article has been updated with the Open Access under Commercial License.
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http://dx.doi.org/10.1007/s40262-018-0722-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6325978PMC
January 2019

Clinical T Cell Receptor Repertoire Deep Sequencing and Analysis: An Application to Monitor Immune Reconstitution Following Cord Blood Transplantation.

Front Immunol 2018 5;9:2547. Epub 2018 Nov 5.

Infection, Immunity and Inflammation Section, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom.

Spectratyping assays are well recognized as the clinical gold standard for assessing the T cell receptor (TCR) repertoire in haematopoietic stem cell transplant (HSCT) recipients. These assays use length distributions of the hyper variable complementarity-determining region 3 (CDR3) to characterize a patient's T cell immune reconstitution post-transplant. However, whilst useful, TCR spectratyping is notably limited by its resolution, with the technique unable to provide data on the individual clonotypes present in a sample. High-resolution clonotype data are necessary to provide quantitative clinical TCR assessments and to better understand clonotype dynamics during clinically relevant events such as viral infections or GvHD. In this study we developed and applied a CDR3 Next Generation Sequencing (NGS) methodology to assess the TCR repertoire in cord blood transplant (CBT) recipients. Using this, we obtained comprehensive TCR data from 16 CBT patients and 5 control cord samples at Great Ormond Street Hospital (GOSH). These were analyzed to provide a quantitative measurement of the TCR repertoire and its constituents in patients post-CBT. We were able to both recreate and quantify inferences typically drawn from spectratyping data. Additionally, we demonstrate that an NGS approach to TCR assessment can provide novel insights into the recovery of the immune system in these patients. We show that NGS can be used to accurately quantify TCR repertoire diversity and to provide valuable inference on clonotypes detected in a sample. We serially assessed the progress of T cell immune reconstitution demonstrating that there is dramatic variation in TCR diversity immediately following transplantation and that the dynamics of T cell immune reconstitution is perturbed by the presence of GvHD. These findings provide a proof of concept for the adoption of NGS TCR sequencing in clinical practice.
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http://dx.doi.org/10.3389/fimmu.2018.02547DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6231291PMC
September 2019

Treatment dilemmas in asymptomatic children with primary hemophagocytic lymphohistiocytosis.

Blood 2018 11 13;132(19):2088-2096. Epub 2018 Aug 13.

Department of Immunology/Stem Cell Transplant, Great Ormond Street Hospital, London, United Kingdom.

Asymptomatic carriers (ACs) of pathogenic biallelic mutations in causative genes for primary hemophagocytic lymphohistiocytosis (HLH) are at high risk of developing life-threatening HLH, which requires allogeneic hematopoietic stem cell transplantation (HSCT) to be cured. There are no guidelines on the management of these asymptomatic patients. We analyzed the outcomes of pairs of index cases (ICs) and subsequently diagnosed asymptomatic family members carrying the same genetic defect. We collected data from 22 HSCT centers worldwide. Sixty-four children were evaluable. ICs presented with HLH at a median age of 16 months. Seven of 32 ICs died during first-line therapy, and 2 are alive after chemotherapy only. In all, 23/32 underwent HSCT, and 16 of them are alive. At a median follow-up of 36 months from diagnosis, 18/32 ICs are alive. Median age of ACs at diagnosis was 5 months. Ten of 32 ACs activated HLH while being observed, and all underwent HSCT: 6/10 are alive and in complete remission (CR). 22/32 ACs remained asymptomatic, and 6/22 have received no treatment and are in CR at a median follow-up of 39 months. Sixteen of 22 underwent preemptive HSCT: 15/16 are alive and in CR. Eight-year probability of overall survival (pOS) in ACs who did not have activated HLH was significantly higher than that in ICs (95% vs 45%; = .02), and pOS in ACs receiving HSCT before disease activation was significantly higher than in ACs receiving HSCT after HLH activation (93% vs 64%; = .03). Preemptive HSCT in ACs proved to be safe and should be considered.
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http://dx.doi.org/10.1182/blood-2018-01-827485DOI Listing
November 2018

One hundred percent survival after transplantation of 34 patients with Wiskott-Aldrich syndrome over 20 years.

J Allergy Clin Immunol 2018 11 25;142(5):1654-1656.e7. Epub 2018 Jul 25.

Blood and Marrow Transplant Unit, Great Ormond Street Hospital NHS Trust, University College London, London, United Kingdom.

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http://dx.doi.org/10.1016/j.jaci.2018.06.042DOI Listing
November 2018

Multicenter phase 1/2 application of adenovirus-specific T cells in high-risk pediatric patients after allogeneic stem cell transplantation.

Cytotherapy 2018 06 9;20(6):830-838. Epub 2018 May 9.

Molecular and Cellular Immunology Section, Institute of Child Health, University College of London, London, United Kingdom; Department of Immunology, Great Ormond Street Hospital, London, United Kingdom.

Background: Adenovirus (ADV) reactivation can cause significant morbidity and mortality in children after allogeneic stem cell transplantation. Antiviral drugs can control viremia, but viral clearance requires recovery of cell-mediated immunity.

Method: This study was an open-label phase 1/2 study to investigate the feasibility of generating donor-derived ADV-specific T cells (Cytovir ADV, Cell Medica) and to assess the safety of pre-emptive administration of ADV-specific T cells in high-risk pediatric patients after allogeneic hematopoietic stem cell transplantation (HSCT) to treat adenoviremia. Primary safety endpoints included graft-versus-host disease (GvHD), and secondary endpoints determined antiviral responses and use of antiviral drugs.

Results: Between January 2013 and May 2016, 92 donors were enrolled for the production of ADV T cells at three centers in the United Kingdom (UK), and 83 products were generated from 72 mobilized peripheral blood harvests and 20 steady-state whole blood donations. Eight children received Cytovir ADV T cells after standard therapy and all resolved ADV viremia between 15 and 127 days later. ADV-specific T cells were detectable using enzyme-linked immunospot assay (ELISpot) in the peripheral blood of all patients analyzed. Serious adverse events included Grade II GvHD, Astrovirus encephalitis and pancreatitis.

Conclusion: The study demonstrates the safety and feasibility of pre-emptively manufacturing peptide pulsed ADV-specific cells for high-risk pediatric patients after transplantation and provides early evidence of clinical efficacy.
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http://dx.doi.org/10.1016/j.jcyt.2018.03.040DOI Listing
June 2018

Clinical Pharmacokinetics and Dose Recommendations for Posaconazole in Infants and Children.

Clin Pharmacokinet 2019 01;58(1):53-61

Infection, Inflammation, Immunity Section, Room 661, UCL Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK.

Objectives: The objectives of this study were to investigate the population pharmacokinetics of posaconazole in immunocompromised children, evaluate the influence of patient characteristics on posaconazole exposure and perform simulations to recommend optimal starting doses.

Methods: Posaconazole plasma concentrations from paediatric patients undergoing therapeutic drug monitoring were extracted from a tertiary paediatric hospital database. These were merged with covariates collected from electronic sources and case-note reviews. An allometrically scaled population-pharmacokinetic model was developed to investigate the effect of tablet and suspension relative bioavailability, nonlinear bioavailability of suspension, followed by a step-wise covariate model building exercise to identify other important sources of variability.

Results: A total of 338 posaconazole plasma concentrations samples were taken from 117 children aged 5 months to 18 years. A one-compartment model was used, with tablet apparent clearance standardised to a 70-kg individual of 15 L/h. Suspension was found to have decreasing bioavailability with increasing dose; the estimated suspension dose to yield half the tablet bioavailability was 99 mg/m. Diarrhoea and proton pump inhibitors were also associated with reduced suspension bioavailability.

Conclusions: In the largest population-pharmacokinetic study to date in children, we have found similar covariate effects to those seen in adults, but low bioavailability of suspension in patients with diarrhoea or those taking concurrent proton pump inhibitors, which may in particular limit the use of posaconazole in these patients.
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http://dx.doi.org/10.1007/s40262-018-0658-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6326087PMC
January 2019

Allogeneic hematopoietic stem cell transplantation for severe, refractory juvenile idiopathic arthritis.

Blood Adv 2018 04;2(7):777-786

Department of BMT, Great Ormond Street Hospital for Children, National Health Service (NHS) Foundation Trust, London, United Kingdom.

Patients with juvenile idiopathic arthritis (JIA) can experience a severe disease course, with progressive destructive polyarthritis refractory to conventional therapy with disease-modifying antirheumatic drugs including biologics, as well as life-threatening complications including macrophage activation syndrome (MAS). Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative immunomodulatory strategy for patients with such refractory disease. We treated 16 patients in 5 transplant centers between 2007 and 2016: 11 children with systemic JIA and 5 with rheumatoid factor-negative polyarticular JIA; all were either refractory to standard therapy, had developed secondary hemophagocytic lymphohistiocytosis/MAS poorly responsive to treatment, or had failed autologous HSCT. All children received reduced toxicity fludarabine-based conditioning regimens and serotherapy with alemtuzumab. Fourteen of 16 patients are alive with a median follow-up of 29 months (range, 2.8-96 months). All patients had hematological recovery. Three patients had grade II-IV acute graft-versus-host disease. The incidence of viral infections after HSCT was high, likely due to the use of alemtuzumab in already heavily immunosuppressed patients. All patients had significant improvement of arthritis, resolution of MAS, and improved quality of life early following allo-HSCT; most importantly, 11 children achieved complete drug-free remission at the last follow-up. Allo-HSCT using alemtuzumab and reduced toxicity conditioning is a promising therapeutic option for patients with JIA refractory to conventional therapy and/or complicated by MAS. Long-term follow-up is required to ascertain whether disease control following HSCT continues indefinitely.
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http://dx.doi.org/10.1182/bloodadvances.2017014449DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5894259PMC
April 2018

Non-posttransplant lymphoproliferative disorder malignancy after hematopoietic stem cell transplantation in patients with primary immunodeficiency: UK experience.

J Allergy Clin Immunol 2018 06 7;141(6):2319-2321.e1. Epub 2018 Mar 7.

Children's Haemopoietic Stem Cell Transplant Unit, Great North Children's Hospital, Newcastle upon Tyne Hospital NHS Foundation Trust, Newcastle upon Tyne, United Kingdom; Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom. Electronic address:

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http://dx.doi.org/10.1016/j.jaci.2018.02.038DOI Listing
June 2018

Umbilical cord blood transplantation without in vivo T-cell depletion for children with MHC class II deficiency.

J Allergy Clin Immunol 2018 06 31;141(6):2279-2282.e2. Epub 2018 Jan 31.

Departments of Immunology and Bone Marrow Transplant, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, United Kingdom.

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http://dx.doi.org/10.1016/j.jaci.2017.10.051DOI Listing
June 2018

Cord blood transplantation recapitulates fetal ontogeny with a distinct molecular signature that supports CD4 T-cell reconstitution.

Blood Adv 2017 Nov 2;1(24):2206-2216. Epub 2017 Nov 2.

Molecular and Cellular Immunology Section, University College London Institute of Child Health, London, United Kingdom.

Omission of in vivo T-cell depletion promotes rapid, thymic-independent CD4-biased T-cell recovery after cord blood transplant. This enhanced T-cell reconstitution differs from that seen after stem cell transplant from other stem cell sources, but the mechanism is not known. Here, we demonstrate that the transcription profile of naive CD4 T cells from cord blood and that of lymphocytes reconstituting after cord blood transplantation is similar to the transcription profile of fetal CD4 T cells. This profile is distinct to that of naive CD4 T cells from peripheral blood and that of lymphocytes reconstituting after T-replete bone marrow transplantation. The transcription profile of reconstituting naive CD4 T cells from cord blood transplant recipients was upregulated in the T-cell receptor (TCR) signaling pathway and its transcription factor activator protein-1 (AP-1). Furthermore, a small molecule inhibitor of AP-1 proportionally inhibited cord blood CD4 T-cell proliferation ( < .05). Together, these findings suggest that reconstituting cord blood CD4 T cells reflect the properties of fetal ontogenesis, and enhanced TCR signaling is responsible for the rapid restoration of the unique CD4 T-cell biased adaptive immunity after cord blood transplantation.
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http://dx.doi.org/10.1182/bloodadvances.2017010827DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5737134PMC
November 2017

Use of the complement inhibitor Coversin to treat HSCT-associated TMA.

Blood Adv 2017 Jul 3;1(16):1254-1258. Epub 2017 Jul 3.

Great Ormond Street Hospital for Children, London, United Kingdom.

Finding an inherited complement abnormality in HSCT-associated TMA provides a rationale for the use of a complement inhibitor.Alternative complement inhibitors such as Coversin should be considered in patients who are resistant to eculizumab.
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http://dx.doi.org/10.1182/bloodadvances.2016002832DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5728542PMC
July 2017

Treosulfan and Fludarabine Conditioning for Hematopoietic Stem Cell Transplantation in Children with Primary Immunodeficiency: UK Experience.

Biol Blood Marrow Transplant 2018 03 16;24(3):529-536. Epub 2017 Nov 16.

Great Ormond Street Hospital NHS Trust, London, United Kingdom.

We previously published results for 70 children who received conditioning with treosulfan and cyclophosphamide (n = 30) or fludarabine (n = 40) before undergoing hematopoietic stem cell transplantation (HSCT) for primary immunodeficiency (PID). Toxicity was lower and T cell chimerism was better in the patients receiving fludarabine, but cohort numbers were relatively small and follow-up was short. Here we report outcomes of 160 children who received homogeneous conditioning with treosulfan, fludarabine, and, in most cases, alemtuzumab (n = 124). The median age at transplantation was 1.36 years (range, .09 to 18.25 years). Donors included 73 matched unrelated, 54 1 to 3 antigen-mismatched unrelated, 12 matched sibling, 17 other matched family, and 4 haploidentical donors. Stem cell source was peripheral blood stem cells (PBSCs) in 70, bone marrow in 49, and cord blood in 41. Median duration of follow-up was 4.3 years (range, .8 to 9.4 years). Overall survival was 83%. No patients had veno-occlusive disease. Seventy-four patients (46%) had acute GVHD, but only 14 (9%) greater than grade II. Four patients underwent successful retransplantation for graft loss or poor immune reconstitution. Another patient experienced graft rejection and died. There was no association between T cell chimerism >95% and stem cell source, but a significant association was seen between myeloid chimerism >95% and use of PBSCs without an increased risk of significant GVHD compared with other sources. All 11 patients with severe combined immunodeficiency diagnosed at birth were alive at up to 8.7 years of follow-up. Long-term studies are needed to determine late gonadotoxic effects, and pharmacokinetic studies are needed to identify whether specific targeting is advantageous. The combination of treosulfan, fludarabine, and alemtuzumab is associated with excellent results in HSCT for PID.
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http://dx.doi.org/10.1016/j.bbmt.2017.11.009DOI Listing
March 2018

T-cell receptor αβ and CD19 cell-depleted haploidentical and mismatched hematopoietic stem cell transplantation in primary immune deficiency.

J Allergy Clin Immunol 2018 04 3;141(4):1417-1426.e1. Epub 2017 Aug 3.

Department of Immunology and BMT, Great North Children's Hospital, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom.

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is used as a therapeutic approach for primary immunodeficiencies (PIDs). The best outcomes have been achieved with HLA-matched donors, but when a matched donor is not available, a haploidentical or mismatched unrelated donor (mMUD) can be useful. Various strategies are used to mitigate the risk of graft-versus-host disease (GvHD) and rejection associated with such transplants.

Objective: We sought to evaluate the outcomes of haploidentical or mMUD HSCT after depleting GvHD-causing T-cell receptor (TCR) αβ CD3 cells from the graft.

Methods: CD3TCRαβ/CD19 depleted grafts were given in conditioned (except 3) children with PIDs. Treosulfan (busulfan in 1 patient), fludarabine, thiotepa, and anti-thymocyte globulin or alemtuzumab conditioning were used in 77% of cases, and all but 4 received GvHD prophylaxis.

Results: Twenty-five patients with 12 types of PIDs received 26 HSCTs. Three underwent transplantation for refractory GvHD that developed after the first cord transplantation. At a median follow-up of 20.8 months (range, 5 month-3.3 years), 21 of 25 patients survived and were cured of underlying immunodeficiency. Overall and event-free survival at 3 years were 83.9% and 80.4%, respectively. Cumulative incidence of grade II to IV acute GvHD was 22% ± 8.7%. No case of visceral or chronic GvHD was seen. Cumulative incidences of graft failure, cytomegalovirus, and/or adenoviral infections and transplant-related mortality at 1 year were 4.2% ± 4.1%, 58.8% ± 9.8%, and 16.1% ± 7.4%, respectively. Patients undergoing transplantation with systemic viral infections had poor survival in comparison with those with absent or resolved infections (33.3% vs 100%).

Conclusion: CD3TCRαβ and CD19 cell-depleted haploidentical or mMUD HSCT is a practical and viable alternative for children with a range of PIDs.
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http://dx.doi.org/10.1016/j.jaci.2017.07.008DOI Listing
April 2018

Molecular remission of infant B-ALL after infusion of universal TALEN gene-edited CAR T cells.

Sci Transl Med 2017 01;9(374)

Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK.

Autologous T cells engineered to express chimeric antigen receptor against the B cell antigen CD19 (CAR19) are achieving marked leukemic remissions in early-phase trials but can be difficult to manufacture, especially in infants or heavily treated patients. We generated universal CAR19 (UCART19) T cells by lentiviral transduction of non-human leukocyte antigen-matched donor cells and simultaneous transcription activator-like effector nuclease (TALEN)-mediated gene editing of T cell receptor α chain and CD52 gene loci. Two infants with relapsed refractory CD19 B cell acute lymphoblastic leukemia received lymphodepleting chemotherapy and anti-CD52 serotherapy, followed by a single-dose infusion of UCART19 cells. Molecular remissions were achieved within 28 days in both infants, and UCART19 cells persisted until conditioning ahead of successful allogeneic stem cell transplantation. This bridge-to-transplantation strategy demonstrates the therapeutic potential of gene-editing technology.
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http://dx.doi.org/10.1126/scitranslmed.aaj2013DOI Listing
January 2017

Association of busulfan exposure with survival and toxicity after haemopoietic cell transplantation in children and young adults: a multicentre, retrospective cohort analysis.

Lancet Haematol 2016 Nov 13;3(11):e526-e536. Epub 2016 Oct 13.

Division of Pediatrics, Blood and Marrow Transplantation Program, University Medical Center Utrecht, Utrecht, Netherlands; Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands. Electronic address:

Background: Intravenous busulfan combined with therapeutic drug monitoring to guide dosing improves outcomes after allogeneic haemopoietic cell transplantation (HCT). The best method to estimate busulfan exposure and optimum exposure in children or young adults remains unclear. We therefore assessed three approaches to estimate intravenous busulfan exposure (expressed as cumulative area under the curve [AUC]) and associated busulfan AUC with clinical outcomes in children or young adults undergoing allogeneic HCT.

Methods: In this retrospective analysis, patients from 15 centres in the Netherlands, USA, Canada, Switzerland, UK, Italy, Germany, and Australia who received a busulfan-based conditioning regimen between March 18, 2001, and Feb 12, 2015, were included. Cumulative AUC was calculated by numerical integration using non-linear mixed effect modelling (AUC), non-compartmental analysis (AUC from 0 to infinity [AUC] and to the next dose [AUC]), and by individual centres using various approaches (AUC). The main outcome of interest was event-free survival. Other outcomes of interest were graft failure or relapse, or both; transplantation-related mortality; acute toxicity (veno-occlusive disease or acute graft versus-host disease [GvHD]); chronic GvHD; overall survival; and chronic-GvHD-free event-free survival. We used propensity-score-adjusted Cox proportional hazard models, Weibull models, and Fine-Gray competing risk regressions for statistical analyses.

Findings: 790 patients were enrolled, 674 of whom were included: 274 (41%) with malignant and 400 (59%) with non-malignant disease. Median age was 4·5 years (IQR 1·4-10·7). The median busulfan AUC was 74·4 mg × h/L (95% CI 31·1-104·6), which correlated with the standardised method AUC (r=0·74), but the latter correlated poorly with AUC (r=0·35). Estimated 2-year event-free survival was 69·7% (95% CI 66·2-73·0). Event-free survival at 2 years was 77·0% (95% CI 72·1-82·9) in the 257 patients with an optimum intravenous busulfan AUC of 78-101 mg × h/L compared with 66·1% (60·9-71·4) in the 235 patients at the low historical target of 58-86 mg × h/L and 49·5% (29·2-66·0) in the 44 patients with a high (>101 mg × h/L) busulfan AUC (p=0·011). Compared with the low AUC group, graft failure or relapse occurred less frequently in the optimum AUC group (hazard ratio [HR] 0·57, 95% CI 0·39-0·84; p=0·0041). Acute toxicity (HR 1·69, 1·12-2·57; p=0·013) and transplantation-related mortality (2·99, 1·82-4·92; p<0·0001) were significantly higher in the high AUC group (>101 mg × h/L) than in the low AUC group (<78 mg × h/L), independent of indication; no difference was noted between AUC groups for chronic GvHD (<78 mg × h/L vs ≥78 mg × h/L, HR 1·30, 95% CI 0·73-2·33; p=0·37).

Interpretation: Improved clinical outcomes are likely to be achieved by targeting the busulfan AUC to 78-101 mg × h/L using a new validated pharmacokinetic model for all indications.

Funding: Research Allocation Program and the UCSF Helen Friller Family Comprehensive Cancer Center and the Mt Zion Health Fund of the University of California, San Francisco.
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http://dx.doi.org/10.1016/S2352-3026(16)30114-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5159247PMC
November 2016

Haematopoietic stem cell transplantation in inborn errors of metabolism.

Curr Opin Hematol 2016 11;23(6):530-535

aBone Marrow Transplantation Department, Great Ormond Street Hospital, London, UK bDepartment of Haematology/BMT, Royal Manchester Children's Hospital, Manchester, UK.

Purpose Of Review: This review summarizes the main results of haematopoietic stem cell transplantation (HSCT) in selected inborn errors of metabolism (IEMs).

Recent Findings: Early diagnosis and immediate referral to an IEM specialist is of paramount importance to improve clinical outcome: patients who are transplanted early or in their presymptomatic phase generally achieve better correction of their somatic symptoms and neurocognitive development. Long-term outcome in children with Hurler syndrome is influenced by age at HSCT, baseline clinical status and post-HSCT enzyme levels. Myeloablative Busulfan-based conditioning regimens with therapeutic drug monitoring are recommended to achieve full donor engraftment and more robust enzyme delivery after HSCT. Gene therapy can lead to production of supranormal enzyme levels, and preliminary clinical results are also promising in IEMs historically not responsive to allogeneic HSCT.

Summary: Allogeneic HSCT has largely contributed to the improved survival and quality of life of many children affected by IEMs. Neonatal screening could enable earlier HSCT, and this might significantly reduce residual disease burden and improve clinical outcome. Novel strategies, such as gene therapy, have shown encouraging clinical results in selected IEMs and might become more widely available in the future, with potentially better enzyme delivery and reduced transplant-related toxicity.
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http://dx.doi.org/10.1097/MOH.0000000000000289DOI Listing
November 2016