Deaminase-deficient Severe Combined Immunodeficiency Research Articles

Early immune reconstitution in an infant with adenosine deaminase deficient severe combined immunodeficiency started on enzyme replacement therapy

Severe Combined Immunodeficiency (SCID) due to adenosine deaminase (ADA) deficiency is an inborn error of immunity resulting in the accumulation of adenosine and deoxyadenosine leading to a T-B-NK-phenotype. Enzyme Replacement Therapy with Elapegademase-IvIr is typically used as a bridge prior to undergoing definitive treatment with HSCT or HSC-GT.We report a full-term female infant born to Caucasian parents. Immediate newborn course was unremarkable. She had two borderline newborn screens (NBS) for SCID. There was no consanguinity or family history of immunodeficiency. Physical exam was normal except for absent tonsils. She had profound lymphopenia (Absolute Lymphocyte Count of 210 cells/mL), and initial lymphocyte enumeration showed low CD3 cells (169/mL), decreased CD19 cells (6/mL) and CD16/56+ cells (26/mL) consistent with a T-B-NK- SCID. There was no maternal engraftment. Immunoglobulin studies showed normal IgG (325) with low IgM and IgA. Mitogen proliferation to phytohemagglutinin (PHA) was significantly low (10,200 CPM).A SCID genetics panel revealed two pathogenic variants in ADA (p.Glu319fs and p.Arg149Trp). Biochemical testing confirmed absent ADA activity and elevated total deoxyadenosine nucleotides (dAXP) of 40.3% in RBCs (normally undetectable), consistent with the diagnosis of ADA-SCID. She was promptly started on ERT twice weekly and developed full immune reconstitution of her T-cells, B-cells and NK-cells after 21 days. At that time, her dAXP remained elevated at 10%. Her T-cell function also normalized (PHA 239,562 CPM).We report an infant with ADA-SCID who had two borderline NBS results and developed full immune reconstitution 3 weeks after starting ERT. This is unusual since thymopoiesis typically requires 60–90 days for T-cell reconstitution. While B and NK immune reconstitution typically occurs early, early T-cell numbers lag behind, especially while dAXP levels remain measurable. Both genetic variants in this patient are severe, but somatic mosaicism with reversion of the Arg149Trp point mutation might account for rapid T-cell recovery; further T-cell analysis is planned to assess this possibility. This child is the first case of SCID diagnosed in North Carolina following a borderline NBS, as opposed to abnormal, reinforcing the utility of highly-sensitive TREC thresholds for identification of at-risk infants. [Display omitted] [Display omitted]

Gene Therapy Hits Its Stride in the Clinic

Gene Therapy Hits Its Stride in the Clinic

PPM6 Cost-Effectiveness and Reimbursement of CELL and GENE Therapies: A Review

Cell and gene therapy products offer potential curative effects to chronic but are imbedded with data uncertainty and high-costs. New reimbursement models are emerging, that serve as a catalyst for adoption of cell and gene therapies in the future. This research aims to review the cost-effectiveness evidence for ex vivo gene therapy Strimvelis, and CAR T-cell therapies Kymriah (Tisagenlecleucel), Yescarta (Axicabtagene Ciloleucel) and explore the emerging reimbursement models. Pubmed, MEDLINE and Cochrane Library database were searched to December 2019 for (i) ex vivo gene therapy for adenosine deaminase deficiency severe combined immunodeficiency (Strimvelis) and CAR T-cell therapies (ii) tisagenlecleucel (Kymriah) and (iii) axicabtagene ciloleucel (Yescarta) and (iv) reimbursement models for cell and gene therapies. A total of 13 articles were identified as relevant for full-text screening: 8 (66%) analysed cost-effectiveness of Strimvelis, Kymriah and Yescarta in a NHS healthcare setting. The cost per quality adjusted life year (QALY) estimates were highly variable due to uncertainty in the data. New reimbursement models are set to accommodate future high-cost of cell and gene therapy with data uncertainty. Proposed managed access agreements (MMA) encourage collaboration between NHS England and the manufacturer to manage the risks.

Chest Radiographs for Distinguishing ADA-SCID from Other Forms of SCID.

Early differentiation of adenosine deaminase deficient severe combined immunodeficiency (ADA-SCID) from other forms of SCID may initiate appropriate treatment interventions with the aim of metabolic detoxification and improved outcome. Our hypothesis was that previously described radiological features (inferior scapular angle squaring and spurring and costochondral cupping) can differentiate ADA-SCID from other forms of SCID. Chest radiographs at clinical presentation between 2000 and 2017 of children with ADA-SCID were retrospectively included, provided that the radiological features were assessable. Random chest radiographs of children with other forms of SCID were included for comparison. Three paediatric radiologists (2 senior, 1 junior) assessed the radiographs for the specific radiological features and stated their diagnosis (ADA-SCID or non-ADA-SCID). An optimal threshold for test performance was defined using a ROC curve. Thirty-six patients with ADA-SCID and twenty-five patients with non-ADA-SCID were included (median age 3.8 months). The optimal threshold for test performance was at approximately < 7 months old: sensitivity 91.7%, specificity 80.7%, interreader agreement was k = 0.709, AUC 0.862. The positive likelihood ratio for scapular squaring, scapular spur, and costochondral cupping was 4.0, 54.6 and 7.8, respectively. The test was valid when performed by both senior and junior paediatric radiologists. Radiological features such as scapular spurring, scapular squaring and costochondral cupping can reliably differentiate between ADA-SCID and other forms of SCID. This is true for children aged approximately < 7 months, and this is reliable when assessed by both senior and junior paediatric radiologists.

Cytoreductive conditioning intensity predicts clonal diversity in ADA-SCID retroviral gene therapy patients

AbstractRetroviral gene therapy has proved efficacious for multiple genetic diseases of the hematopoietic system, but roughly half of clinical gene therapy trial protocols using gammaretroviral vectors have reported leukemias in some of the patients treated. In dramatic contrast, 39 adenosine deaminase–deficient severe combined immunodeficiency (ADA-SCID) patients have been treated with 4 distinct gammaretroviral vectors without oncogenic consequence. We investigated clonal dynamics and diversity in a cohort of 15 ADA-SCID children treated with gammaretroviral vectors and found clear evidence of genotoxicity, indicated by numerous common integration sites near proto-oncogenes and by increased abundance of clones with integrations near MECOM and LMO2. These clones showed stable behavior over multiple years and never expanded to the point of dominance or dysplasia. One patient developed a benign clonal dominance that could not be attributed to insertional mutagenesis and instead likely resulted from expansion of a transduced natural killer clone in response to chronic Epstein-Barr virus viremia. Clonal diversity and T-cell repertoire, measured by vector integration site sequencing and T-cell receptor β-chain rearrangement sequencing, correlated significantly with the amount of busulfan preconditioning delivered to patients and to CD34+ cell dose. These data, in combination with results of other ADA-SCID gene therapy trials, suggest that disease background may be a crucial factor in leukemogenic potential of retroviral gene therapy and underscore the importance of cytoreductive conditioning in this type of gene therapy approach.

Good Laboratory Practice Preclinical Safety Studies for GSK2696273 (MLV Vector-Based Ex Vivo Gene Therapy for Adenosine Deaminase Deficiency Severe Combined Immunodeficiency) in NSG Mice.

GSK2696273 (autologous CD34+ cells transduced with retroviral vector that encodes for the human adenosine deaminase [ADA] enzyme) is a gamma-retroviral ex vivo gene therapy of bone marrow-derived CD34+ cells for the treatment of adenosine deaminase deficiency severe combined immunodeficiency (ADA-SCID). ADA-SCID is a severe monogenic disease characterized by immunologic and nonimmunologic symptoms. Bone-marrow transplant from a matched related donor is the treatment of choice, but it is available for only a small proportion of patients. Ex vivo gene therapy of patient bone-marrow CD34+ cells is an alternative treatment. In order to prepare for a marketing authorization application in the European Union, preclinical safety studies in mice were requested by the European Medicines Agency (EMA). A pilot study and a main biodistribution study were performed according to Good Laboratory Practice (GLP) at the San Raffaele Telethon Institute for Gene Therapy test facility. In the main study, human umbilical cord blood (UCB)-derived CD34+ cells were transduced with gamma-retroviral vector used in the production of GSK2696273. Groups of 10 male and 10 female NOD-SCID gamma (NSG) mice were injected intravenously with a single dose of transduced- or mock-transduced UCB CD34+ cells, and they were observed for 4 months. Engraftment and multilineage differentiation of blood cells was observed in the majority of animals in both groups. There was no significant difference in the level of chimerism between the two groups. In the gene therapy group, vector was detectable in lymphohemopoietic and nonlymphohemopoietic tissues, consistent with the presence of gene-modified human hematopoietic donor cells. Given the absence of relevant safety concerns in the data, the nonclinical studies and the clinical experience with GSK2696273 supported a successful application for market authorization in the European Union for the treatment of ADA-SCID patients, for whom no suitable human leukocyte antigen-matched related donor is available.

A Shot in the Bone Corrects a Genetic Disease

A Shot in the Bone Corrects a Genetic Disease

Progress in gene therapy for primary immunodeficiencies using lentiviral vectors.

This review gives an overview over the most recent progress in the field of lentiviral gene therapy for primary immunodeficiencies (PIDs). The history and state-of-the-art of lentiviral vector development are summarized and the recent advancements for a number of selected diseases are reviewed in detail. Past retroviral vector trials for these diseases, the most recent improvements of lentiviral vector platforms and their application in preclinical development as well as ongoing clinical trials are discussed. Main focus is on the preclinical studies and clinical trials for the treatment of Wiskott-Aldrich syndrome, chronic granulomatous disease, adenosine deaminase deficient severe combined immunodeficiency (ADA-SCID) and X-linked severe combined immunodeficiency with lentiviral gene therapy. Gene therapy for PIDs is an effective treatment, providing potential long-term clinical benefit for affected patients. Substantial progress has been made to make lentiviral gene therapy platforms available for a number of rare genetic diseases. Although many ongoing gene therapy trials are based on ex-vivo approaches with autologous hematopoietic stem cells, other approaches such as in-vivo gene therapy or gene-repair platforms might provide further advancement for certain PIDs.

Neutropenia in primary immunodeficiency.

Neutropenia is a feature of several primary immunodeficiency diseases (PIDDs). Because of the diverse pathophysiologies of the PIDDs and the rarity of each disorder, data are often lacking, leading to the necessity of empiric treatment. Recent developments in the understanding of neutropenia in several of the PIDDs make a review of the data timely. The category of severe congenital neutropenia continues to expand. Mutations in G6PC3 have been identified as the cause of neutropenia in a minority of previously molecularly undefined cases. Recent advances have broadened our understanding of the pathophysiology and the clinical expression of this disorder. A possible function of the C16orf57 gene has been hypothesized that may explain the clinical overlap between Clerucuzio-type poikiloderma with neutropenia and other marrow diseases. Plerixafor has been shown to be a potentially useful treatment in the warts, hypogammaglobulinemia, infection, and myelokathexis syndrome. Investigations of patients with adenosine deaminase deficient severe combined immunodeficiency have identified neutropenia, and particularly susceptibility to myelotoxins, as a feature of this disorder. Granulocyte-colony stimulating factor is the treatment of choice for neutropenia in PIDD, whereas hematopoietic cell transplantation is the only curative option. The number of PIDDs associated with neutropenia has increased, as has our understanding of the range of phenotypes. Additional data and hypotheses have been generated helping to explain the diversity of presentations of neutropenia in PIDDs.

Outcome of hematopoietic stem cell transplantation for adenosine deaminase–deficient severe combined immunodeficiency

AbstractDeficiency of the purine salvage enzyme adenosine deaminase leads to SCID (ADA-SCID). Hematopoietic cell transplantation (HCT) can lead to a permanent cure of SCID; however, little data are available on outcome of HCT for ADA-SCID in particular. In this multicenter retrospective study, we analyzed outcome of HCT in 106 patients with ADA-SCID who received a total of 119 transplants. HCT from matched sibling and family donors (MSDs, MFDs) had significantly better overall survival (86% and 81%) in comparison with HCT from matched unrelated (66%; P < .05) and haploidentical donors (43%; P < .001). Superior overall survival was also seen in patients who received unconditioned transplants in comparison with myeloablative procedures (81% vs 54%; P < .003), although in unconditioned haploidentical donor HCT, nonengraftment was a major problem. Long-term immune recovery showed that regardless of transplant type, overall T-cell numbers were similar, although a faster rate of T-cell recovery was observed after MSD/MFD HCT. Humoral immunity and donor B-cell engraftment was achieved in nearly all evaluable surviving patients and was seen even after unconditioned HCT. These data detail for the first time the outcomes of HCT for ADA-SCID and show that, if patients survive HCT, long-term cellular and humoral immune recovery is achieved.

Challenges in Vector and Trial Design Using Retroviral Vectors for Long-Term Gene Correction in Hematopoietic Stem Cell Gene Therapy

Over the past two decades, incredible progress has been made using gene therapy for inherited severe immunodeficiency disorders, such as X-linked severe combined immunodeficiency disorder (SCID-X1) and adenosine deaminase deficiency–severe combined immunodeficiency disorder (ADA-SCID).1,2,3 However, for reasons that remain unclear, gene transfer for SCID-X1 has also been associated with some cases of vector-induced leukemia whereas no cases have been seen in the ADA-SCID trials despite the common use of g-retroviral vectors. The first case was reported in a French gene transfer trial for SCID-X1.4 Over the next six years, an additional three cases were reported in that trial and one in a second SCID-X1 trial that enrolled a combined total of 20 subjects.2 Unfortunately, genotoxicity would not remain confined to SCID-X1. Recent reports of insertional mutagenesis leading to myelodysplastic syndrome in a trial for chronic granulomatous disease and a case of leukemia in a trial for Wiskott-Aldrich syndrome (WAS), both of which used g-retroviral vectors, underscored that this type of toxicity can also apply to other disease settings.5,6,7 In all these cases, insertion of the g-retroviral vector near known proto-oncogenes led to enhancer-mediated expression of these proto-oncogenes.

Induced pluripotent stem cells and primary immunodeficiencies: A new frontier reached, a new world beyond?

Few articles in recent years have generated such interest and excitement as the report by Takahashi and Yamanaka that adult stem cells could be reprogrammed to a pluripotent state. This study, closely followed bymany others, demonstrated that cells from somatic tissue were not permanently differentiated and could, through the forced expression of specific transcription factors, be reprogrammed into cells that had all the transdifferentiation capacities of embryonic or other previously defined stem cell forms. The potential of these findings was immediately evident to not only stem cell biologists but also to scientists and physicians working in many diverse areas of medicine. The use of embryonic stem cells had already shown the enormous potential of stem cell medicine in allowing the generation of different tissues, organs, and eventually whole organisms but was still limited both technically and ethically by the reliance on embryonic tissue. Therefore the ability to take cell types, such as skin fibroblasts or, more recently, peripheral blood, and generate induced pluripotent stem (iPS) cells and then differentiate them into numerous other cell types provided a far more accessible and almost limitless mechanism to understand disease pathogenesis, screen for drug interventions, and develop regenerative or gene-modifying therapeutic strategies. In this edition of the Journal, Pessach et al demonstrate that iPS cells can be generated for various different forms of immunodeficiencies. This in itself is not entirely novel because iPS cells generated from a patient with adenosine deaminase deficiency–severe combined immunodeficiency have been previously reported, and it is very likely that iPS cells from patients with other immunodeficiencies are currently being generated inmany other laboratories. However, although this is the first formal report of this technique for a number of different forms of immunodeficiency, the importance of this article lies not in the technology or the rigor with which these lines have been characterized but in the possibilities that this technology holds for primary immunodeficiencies.

Lentiviral-mediated Genetic Correction of Hematopoietic and Mesenchymal Progenitor Cells From Fanconi Anemia Patients

Previous clinical trials based on the genetic correction of purified CD34(+) cells with gamma-retroviral vectors have demonstrated clinical efficacy in different monogenic diseases, including X-linked severe combined immunodeficiency, adenosine deaminase deficient severe combined immunodeficiency and chronic granulomatous disease. Similar protocols, however, failed to engraft Fanconi anemia (FA) patients with genetically corrected cells. In this study, we first aimed to correlate the hematological status of 27 FA patients with CD34(+) cell values determined in their bone marrow (BM). Strikingly, no correlation between these parameters was observed, although good correlations were obtained when numbers of colony-forming cells (CFCs) were considered. Based on these results, and because purified FA CD34(+) cells might have suboptimal repopulating properties, we investigated the possibility of genetically correcting unselected BM samples from FA patients. Our data show that the lentiviral transduction of unselected FA BM cells mediates an efficient phenotypic correction of hematopoietic progenitor cells and also of CD34(-) mesenchymal stromal cells (MSCs), with a reported role in hematopoietic engraftment. Our results suggest that gene therapy protocols appropriate for the treatment of different monogenic diseases may not be adequate for stem cell diseases like FA. We propose a new approach for the gene therapy of FA based on the rapid transduction of unselected hematopoietic grafts with lentiviral vectors (LVs).

Reconstitution of immune function in adenosine deaminase deficient severe combined immunodeficiency following hematopoietic stem cell gene therapy

Reconstitution of immune function in adenosine deaminase deficient severe combined immunodeficiency following hematopoietic stem cell gene therapy

Perspectives of gene therapy for primary immunodeficiencies

Standard therapies for patients with severe primary immunodeficiencies include bone marrow transplantation and, for adenosine deaminase deficiency, enzyme replacement. In the last decade, gene therapy has been developed as an alternative for these conditions. We summarize the recent advances in gene therapy for primary immunodeficiencies and discuss the unexpected occurrence of leukemia in a gene therapy trial for X-linked severe combined immunodeficiency. Eight of 10 infants with X-linked severe combined immunodeficiency who received autologous hematopoietic stem cells transduced with a retroviral vector carrying the IL2RG complementary DNA achieved immune reconstitution. However, the two youngest patients developed leukemic expansions of gene-corrected cells. The first case had proliferation of a gamma delta T cell clone, and the second case had three alpha beta T cell clones derived from a single transduced progenitor. Leukemic cells in both patients aberrantly expressed the LIM domain only-2 transcription factor due to retroviral vector insertions in this locus. After receiving anti-leukemic treatment one patient achieved a lasting remission, but the other relapsed. Four adenosine deaminase deficient severe combined immunodeficiency patients also developed functional immunity after receiving autologous hematopoietic stem cells transduced with the adenosine deaminase gene complementary DNA following submyeloablative chemotherapy. Chronic granulomatous disease, Wiskott-Aldrich syndrome, JAK3 deficiency and RAG2 deficiency are other immunodeficiencies being studied as candidates for gene therapy. Gene therapy is a promising therapeutic option for some primary immunodeficiencies, especially when cells expressing the correct gene have a selective advantage. More clinical trials with closer patient monitoring are under way to define which patients may benefit from this approach, and strategies are being developed to understand and ultimately reduce the risk of leukemia secondary to retroviral vector insertion.

Gene therapy for severe combined immunodeficiency

Severe combined immunodeficiency disorders are ideal candidates for gene therapy. Current conventional treatments have significant associated toxicities and often result in incomplete immune reconstitution. The definition of the molecular pathophysiology of the diseases, together with the prediction that gene corrected cells have significant growth and survival advantage has led to clinical gene therapy studies. Clear therapeutic benefits have been demonstrated in patients with adenosine deaminase deficient severe combined immunodeficiency and X-linked severe combined immunodeficiency. Serious complications have arisen, however, and further longitudinal research to quantify benefit and risk is required. Improved and targeted gene deliveries are future goals, but for some primary immunodeficiencies, gene therapy is set to become the standard treatment.

Cognitive and behavioral abnormalities in adenosine deaminase deficient severe combined immunodeficiency

Objective: The objective was to evaluate the cognitive, behavioral, and neurodevelopmental function in patients with adenosine deaminase deficient severe combined immunodeficiency (ADA-SCID) and to compare the findings with those of a case control group of patients without ADA-SCID. Study design: Case-matched pairs of patients with ADA-SCID (n = 11) and patients without ADA-SCID who had undergone bone marrow transplantation were recruited. Subjects were assessed by age-appropriate standard tests of intelligence, behavior, and neurodevelopment. Results: Cognitive ability was not significantly different between the 2 groups, but patients with ADA-SCID showed a significant inverse correlation between deoxyadenosinetrisphosphate levels at diagnosis and IQ (P =.048). Behavioral assessment showed that patients with ADA-SCID functioned in the pathologic range on all domains, whereas mean scores for the control group were within normal limits. Behavioral impairment in patients with ADA-SCID also showed a significant positive correlation with age (P =.026). Conclusions: Cognitive function in ADA deficiency is adversely affected by the severity of metabolic derangement at the time of diagnosis. In addition, patients with ADA-SCID have significant behavioral abnormalities after transplantation. These defects are not due to the transplant procedure but reflect the systemic nature of ADA deficiency. These findings have important implications for future medical and nonmedical management strategies. (J Pediatr 2001;139:44-50)

Effects of metabolic disorders on the brain: Can these effects be reversed with bone marrow transplantation?

Effects of metabolic disorders on the brain: Can these effects be reversed with bone marrow transplantation?

276 Antigen-specific humoral and cellular immune responses during treatment of adenosine deaminase deficient severe combined immunodeficiency (ADA-SCID) with polyethylene glycol-modified bovine adenosine deaminase (PEG-ADA)

276 Antigen-specific humoral and cellular immune responses during treatment of adenosine deaminase deficient severe combined immunodeficiency (ADA-SCID) with polyethylene glycol-modified bovine adenosine deaminase (PEG-ADA)

PROCEEDINGS OF THE AUSTRALIAN SOCIETY FOR MEDICAL RESEARCH

PROCEEDINGS OF THE AUSTRALIAN SOCIETY FOR MEDICAL RESEARCH