title: Recombination-activating gene 1 (Rag1)-deficient mice with severe combined immunodeficiency treated with lentiviral gene therapy demonstrate autoimmune Omenn-like syndrome.
abstract: BACKGROUND
  Recombination-activating gene 1 (RAG1) deficiency results in severe combined immunodeficiency (SCID) caused by a complete lack of T and B lymphocytes. If untreated, patients succumb to recurrent infections.
  
  
  OBJECTIVE
  We sought to develop lentiviral gene therapy for RAG1-induced SCID and to test its safety.
  
  
  METHODS
  Constructs containing the viral spleen-focus-forming virus (SF), ubiquitous promoters, or cell type-restricted promoters driving sequence-optimized RAG1 were compared for efficacy and safety in sublethally preconditioned Rag1(-/-) mice undergoing transplantation with transduced bone marrow progenitors.
  
  
  RESULTS
  Peripheral blood CD3(+) T-cell reconstitution was achieved with SF, ubiquitous promoters, and cell type-restricted promoters but 3- to 18-fold lower than that seen in wild-type mice, and with a compromised CD4(+)/CD8(+) ratio. Mitogen-mediated T-cell responses and T cell-dependent and T cell-independent B-cell responses were not restored, and T-cell receptor patterns were skewed. Reconstitution of mature peripheral blood B cells was approximately 20-fold less for the SF vector than in wild-type mice and often not detectable with the other promoters, and plasma immunoglobulin levels were abnormal. Two months after transplantation, gene therapy-treated mice had rashes with cellular tissue infiltrates, activated peripheral blood CD44(+)CD69(+) T cells, high plasma IgE levels, antibodies against double-stranded DNA, and increased B cell-activating factor levels. Only rather high SF vector copy numbers could boost T- and B-cell reconstitution, but mRNA expression levels during T- and B-cell progenitor stages consistently remained less than wild-type levels.
  
  
  CONCLUSIONS
  These results underline that further development is required for improved expression to successfully treat patients with RAG1-induced SCID while maintaining low vector copy numbers and minimizing potential risks, including autoimmune reactions resembling Omenn syndrome.
authors: Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Niek P
authors: NP
authors: van Til
authors: Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Roya
authors: R
authors: Sarwari
authors: Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Trudi P
authors: TP
authors: Visser
authors: INSERM U768, Université René Descartes, and Hôpital Necker-Enfants Malades, Paris, France; Department of Pediatric Oncology, Hematology and Clinical Immunology, Center for Child and Adolescent Health, Heinrich Heine University, Düsseldorf, Germany.
authors: Julia
authors: J
authors: Hauer
authors: INSERM U768, Université René Descartes, and Hôpital Necker-Enfants Malades, Paris, France.
authors: Chantal
authors: C
authors: Lagresle-Peyrou
authors: Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Guus
authors: G
authors: van der Velden
authors: Immunology Institute, Department of Medicine, Mount Sinai School of Medicine, New York, NY.
authors: Vidyasagar
authors: V
authors: Malshetty
authors: Immunology Institute, Department of Medicine, Mount Sinai School of Medicine, New York, NY.
authors: Patricia
authors: P
authors: Cortes
authors: INSERM U781 Laboratoire de transfert de gènes, Hôpital Necker-Enfants Malades, Paris, France.
authors: Arnaud
authors: A
authors: Jollet
authors: INSERM U781 Laboratoire de transfert de gènes, Hôpital Necker-Enfants Malades, Paris, France.
authors: Olivier
authors: O
authors: Danos
authors: CNR-IRGB, Milan Unit, Milan, Italy; Humanitas Clinical and Research Center, Milan, Italy.
authors: Barbara
authors: B
authors: Cassani
authors: Molecular Immunology Unit, Centre for Immunodeficiency, Institute of Child Health, University College London, London, United Kingdom.
authors: Fang
authors: F
authors: Zhang
authors: Molecular Immunology Unit, Centre for Immunodeficiency, Institute of Child Health, University College London, London, United Kingdom.
authors: Adrian J
authors: AJ
authors: Thrasher
authors: Department of Pathology, University of Brescia, Brescia, Italy.
authors: Elena
authors: E
authors: Fontana
authors: Department of Pathology, University of Brescia, Brescia, Italy.
authors: Pietro L
authors: PL
authors: Poliani
authors: INSERM U768, Université René Descartes, and Hôpital Necker-Enfants Malades, Paris, France; Department of Biotherapy, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris (AP-HP), Université René Descartes, and INSERM, Centre d'Investigation Clinique intégré en Biothérapies, Groupe Hospitalier Universitaire Ouest, AP-HP, Paris, France.
authors: Marina
authors: M
authors: Cavazzana
authors: Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Monique M A
authors: MM
authors: Verstegen
authors: CNR-IRGB, Milan Unit, Milan, Italy; Telethon Institute for Gene Therapy-H San Raffaele, Milan, Italy.
authors: Anna
authors: A
authors: Villa
authors: Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands. Electronic address: g.wagemaker@genetherapy.nl.
authors: Gerard
authors: G
authors: Wagemaker
mesh_terms: D000818:Animals; D015551:Autoimmunity / Q000235:genetics; D001854:Bone Marrow Cells / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D018628:Gene Dosage; D015870:Gene Expression; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics*; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D016130:Immunophenotyping; D016086:Lentivirus / Q000235:genetics*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010641:Phenotype; D016511:Severe Combined Immunodeficiency / Q000235:genetics* / Q000276:immunology / Q000628:therapy*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000378:metabolism; D013950:Thymus Gland / Q000276:immunology; D014161:Transduction, Genetic; D018183:Transplantation Chimera
chemical_list: D018398:Homeodomain Proteins; C064658:RAG-1 protein
keywords: Severe combined immunodeficiency; autoimmune reactions; lentiviral gene therapy