Global Trends and Scientific Contributions in Thalassemia Research (2015–2024): An Integrative Bibliometric and Meta-Analysis of Diagnostic, Genetic and Treatment Approaches

Hematopoietic Stem Cell Gene Therapy with Lentiviral Vector in X-Linked Adrenoleukodystrophy

The EHA Research Roadmap: Hematopoietic Stem Cell Gene Therapy.

A systematic review of quality of life in sickle cell disease and thalassemia after stem cell transplant or gene therapy

High Incidence of Radiation-Induced Cavernous Hemangioma in Long-Term Survivors Who Underwent Hematopoietic Stem Cell Transplantation with Radiation Therapy during Childhood or Adolescence

Chapter ten - Lentiviral Hematopoietic Cell Gene Therapy for X-Linked Adrenoleukodystrophy

Cardiac Arrhythmias and Mortality after Hematopoietic Stem Cell Transplant (HSCT): A Systematic Review and Meta-Analysis

Real-World Outcomes Among Elderly Acute Myeloid Leukemia Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT) is a well-established curative therapy for patients with sickle cell disease (SCD) when using a human leukocyte antigen (HLA)-matched sibling donor. Most patients with SCD do not have a matched sibling donor, thereby significantly limiting the accessibility of this curative option to most patients. HLA-haploidentical HSCT with post-transplant cyclophosphamide expands the donor pool, with current approaches now demonstrating high overall survival, reduced toxicity, and an effective reduction in acute and chronic graft-vs.-host disease (GvHD). Alternatively, autologous genetic therapies appear promising and have the potential to overcome significant barriers associated with allogeneic HSCT, such as donor availability and GvHD. Here the authors each take a viewpoint and discuss what will be the future of curative options for patients with SCD outside of a matched sibling transplantation, specifically haploidentical HSCT vs. gene therapy.

Hematopoietic stem cells have been investigated and applied for the treatment of certain neurological disorders for a long time. Currently, their therapeutic potential is harnessed in autologous and allogeneic hematopoietic stem cell transplantation (HSCT). Autologous HSCT is helpful in immune-mediated neurological diseases such as Multiple Sclerosis. However, clinical benefits derive more from the immunosuppressive conditioning regimen than the interaction between stem cells and the nervous system. Mainly used for hematologic malignancies, allogeneic HSCT explores the therapeutic potential of donor-derived hematopoietic stem cells. In the neurological setting, it has proven to be most valuable in Inborn Errors of Metabolism, a large spectrum of multisystem disorders characterized by congenital deficiencies in enzymes involved in metabolic pathways. Inborn Errors of Metabolism such as X-linked Adrenoleukodystrophy present with brain accumulation of enzymatic substrates that result in progressive inflammatory demyelination. Allogeneic HSCT can halt ongoing inflammatory neural destruction by replacing hematopoietic-originated microglia with donor-derived myeloid precursors. Microglia, the only neural cells successfully transplanted thus far, are the most valuable source of central nervous system metabolic correction and play a significant role in the crosstalk between the brain and hematopoietic stem cells. After transplantation, engrafted donor-derived myeloid cells modulate the neural microenvironment by recapitulating microglial functions and enhancing repair mechanisms such as remyelination. In some disorders, additional benefits result from the donor hematopoietic stem cell secretome that cross-corrects neighboring neural cells via mannose-6-phosphatase paracrine pathways. The limitations of allogeneic HSCT in this setting relate to the slow turnover of microglia and complications such as graft-vs.-host disease. These restraints have accelerated the development of hematopoietic stem cell gene therapy, where autologous hematopoietic stem cells are collected, manipulated ex vivo to overexpress the missing enzyme, and infused back into the patient. With this cellular drug vehicle strategy, the brain is populated by improved cells and exposed to supraphysiological levels of the flawed protein, resulting in metabolic correction. This review focuses on the mechanisms of brain repair resulting from HSCT and gene therapy in Inborn Errors of Metabolism. A brief mention will also be made on immune-mediated nervous system diseases that are treated with this approach.

ABSTRACTIntroductionAllogeneic hematopoietic stem cell transplant (HSCT) and gene therapy (GT) are two potentially curative approaches for sickle cell disease (SCD), but they have never been compared in clinical trials.ObjectiveTo compare the safety and efficacy of HSCT and GT to assist clinicians and patients in making informed treatment decisions.MethodsPhase I-III clinical trials and case reports/series were included. Regimens included HSCT from all stem cell sources, lentiviral gene therapy, and gene editing, with any conditioning regimen. We searched Medline and EMBASE databases as of 1st June 2020 for studies reporting HSCT and GT outcomes in SCD. The Newcastle-Ottawa scale was used to assess the risk of bias. Descriptive statistics and post-hoc imputation for standard deviations of mean change in FEV1 and FVC were performed.ResultsIn total, 56 studies (HSCT, n = 53; GT, n = 3) representing 1,198 patients met inclusion criteria (HSCT, n = 1,158; GT, n = 40). Length of follow-up was 3,881.5 and 58.7 patient-years for HSCT and GT, respectively. Overall quality of evidence was low, with no randomized controlled trials identified. Two-year overall survival for HSCT was 91%; mortality was 2.5% for GT. Acute chest syndrome and vaso-occlusive episodes were reduced post-HSCT and GT. Meta-analysis was not possible due to lack of comparator and heterogeneity in outcome measures reporting. Very few studies reported post-transplant end-organ function. Six secondary malignancies (5 post-HSCT, 1 post-GT) were reported.DiscussionReporting of SCD-related complications and patient-important outcomes is lacking for both strategies. We advocate for standardized reporting to better compare outcomes within and between treatment groups.

Severe combined immunodeficiency (SCID) is a fatal childhood disease unless immune reconstitution is performed early in life, with either hematopoietic stem cell transplantation or gene therapy. One of its subtypes is caused by adenosine deaminase (ADA) enzyme deficiency, which leads to the accumulation of toxic metabolites that impair lymphocyte development and function. With the development of polyethylene glycol-conjugated adenosine deaminase (PEG-ADA) enzyme replacement therapy, many ADA-deficient children with SCID who could not receive a hematopoietic stem cell transplantation or gene therapy survived and had longer and healthier lives. We report a 24-year course of treatment in a patient who was diagnosed with ADA deficiency at 4 months of age. The patient was treated with PEG-ADA, which was the only therapy available for him. The patient's plasma ADA level was regularly monitored and the PEG-ADA dose adjusted accordingly. This treatment has resulted in near-normalization of lymphocyte counts, and his clinical course has been associated with only minor to moderate infections. Thus far, he has had no manifestations of autoimmune or lymphoproliferative disorders. This patient is among the longest to be maintained on PEG-ADA enzyme replacement therapy.

To present an updated appraisal of hematopoietic stem cell transplant (HSCT) and gene therapy for X-linked adrenoleukodystrophy (ALD) in the setting of a novel, presymptomatic approach to disease. Outcomes in HSCT for ALD have been optimized over time due to early patient detection, improved myeloablative conditioning regimens, and adjunctive treatment for patients with advanced cerebral disease. Gene therapy has arrested disease progression in a cohort of boys with childhood cerebral ALD. New therapeutic strategies have provided the clinical basis for the implementation of Newborn Screening (NBS). With the help of advocacy groups, NBS has been implemented, allowing for MRI screening for the onset of cerebral ALD from birth. Gene therapy and optimized hematopoietic stem cell transplant for childhood CALD have changed the natural history of this previously devastating neurological disease.

Metachromatic leukodystrophy (MLD) is a rare autosomal recessive lysosomal storage disorder caused by disease-causing variants in the gene coding for arylsulfatase A, leading to deficient enzyme activity and subsequent accumulation of sulfatides. MLD is characterized by demyelination and neurodegeneration of the central and peripheral nervous system, manifesting as progressive motor and cognitive defects in affected individuals. This review provides a comprehensive overview of the significant progress made in MLD research in the past decade, regarding natural history, disease and treatment mechanisms, and newborn screening (NBS). Traditionally, MLD has been classified according to age at onset (late-infantile, early-juvenile and late-juvenile, and adult MLD), with earlier forms leading to more rapid neurologic decline. New data show that the type of presenting symptoms further influences the dynamic of disease progression. Patients with a cognitive presentation have a much slower or even no motor decline than patients with a mixed motor and cognitive presentation. Research advancements have enabled improved understanding of the effects of allogeneic hematopoietic stem cell transplantation and the development of novel therapeutic approaches, including hematopoietic stem cell gene therapy, which is now authorized in the EU, United Kingdom, and United States as treatment for selected patients with early-onset forms of MLD. Both hematopoietic stem cell transplantation and hematopoietic stem cell gene therapy are most effective when administered before disease onset. To identify presymptomatic patients, NBS for MLD is becoming available in several countries, resulting in new challenges. Decisions regarding patient eligibility for these treatments in already symptomatic individuals, as well as the timing of treatment for patients identified through NBS, require thorough understanding of disease progression. Biomarkers may be helpful for disease staging and prediction of disease evolution. Moreover, apart from timing, challenges remain regarding optimal treatment strategies across MLD subtypes, especially late-onset MLD, and management of the clinical heterogeneity and course of the disease. Another important issue is ensuring therapy accessibility, which forms a substantial barrier for equitable care. Continued research and international collaboration are essential to address these challenges, with the goal of improving care and outcomes for patients with MLD and their families.

Background: Severe Combined Immunodeficiency (SCID) is a category of inborn errors of immunity where there is impaired T and B cell development and/or function. Artemis SCID (Art-SCID) is characterized by dysfunctional Artemis protein, which is crucial for V(D)J recombination in T and B cell maturation. Art-SCID is fatal without management, and current definitive treatment involves hematopoietic stem cell transplantation (HSCT) or gene therapy. As the prognosis and survival of SCID patients improves, current research has begun unveiling long-term complications and morbidities. Previous literature has reported neurodevelopmental abnormalities in SCID patients, such as developmental delay and Autism Spectrum Disorder (ASD). However, it remains unknown whether these neurodevelopmental differences are linked to the SCID mutation, an adverse outcome of treatment and hospitalization, or comorbid social isolation and psychosocial challenges. Aims: In this case series, we discuss two cases of Art-SCID which presented with neurodevelopmental deficits following successful HSCT. Results: In both cases, SCID was detected on Newborn Screening (NBS), and Art-SCID was confirmed with genetic testing. Both patients were successfully treated with HSCT at 80 days of life, and followed up clinically well, with robust cell counts. Both patients later presented in toddlerhood with developmental, speech and language delay, however only one patient met diagnostic criteria for ASD. Conclusion: The definitive relationship between SCID, HSCT, and neurodevelopmental outcomes remain unclear, and warrants further study to allow for early intervention. We are currently working with colleagues across the country to further investigate and define this complex relationship. Statement of Novelty: We are investigating the complex relationship between SCID, HSCT, and potential neurodevelopmental outcomes. We present two cases of patients with Artemis SCID who were successfully treated with HSCT, and later presented in toddlerhood with developmental, speech, and language delay.

Signal transducer and activator of transcription 5 tyrosine phosphorylation for the diagnosis and monitoring of patients with severe combined immunodeficiency