RESUMEN
Patients with mutations in the Artemis gene display a complete absence of T- and B lymphocytes, together with increased cellular radiosensitivity; this leads to a radiosensitive severe combined immunodeficiency (RS-SCID). Allogenic hematopoietic stem-cell (HSC) transplantation is only partially successful in the absence of an human leukocyte antigen-genoidentical donor, and this has prompted a search for alternative therapeutic approaches such as gene therapy. In this study, a self-inactivated lentiviral vector expressing Artemis was used to complement the Artemis knockout mouse (Art(-/-)). Transplantation of Artemis-transduced HSCs into irradiated Art(-/-) mice restored a stable (over a 15-month period of follow-up) and functional T- and cell repertoire that was comparable to that of control mice. The success of secondary transplantations demonstrated that the HSCs had been transduced. One of thirteen mice developed a thymoma 6 months after gene therapy. Although thymic cells were seen to be carrying two lentiviral integration sites, there was no evidence of lentivirus-driven oncogene activation. The Art(-/-) mice were found to be prone to develop T-cell lymphomas, either spontaneously or after irradiation. These data indicate that the observed lymphoproliferation was probably the consequence of the chromosomal instability associated with the Artemis-deficient background. As a whole, our work provides a basis for supporting the gene therapy approach in Artemis-deficient SCID.
Asunto(s)
Trasplante de Células Madre Hematopoyéticas/métodos , Lentivirus/genética , Proteínas Nucleares/genética , Inmunodeficiencia Combinada Grave/terapia , Animales , Linfocitos B/inmunología , Complejo CD3/análisis , Antígenos CD4/análisis , Antígenos CD8/análisis , Células Cultivadas , Endonucleasas , Femenino , Citometría de Flujo , Terapia Genética/métodos , Vectores Genéticos/genética , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Receptores de Hialuranos/análisis , Subunidad alfa del Receptor de Interleucina-2/análisis , Masculino , Ratones , Ratones Noqueados , Proteínas Nucleares/deficiencia , Proteínas Nucleares/metabolismo , Inmunodeficiencia Combinada Grave/genética , Inmunodeficiencia Combinada Grave/inmunología , Linfocitos T/inmunología , Timo/inmunología , Timo/patología , Transducción GenéticaAsunto(s)
Trasplante de Células Madre Hematopoyéticas/efectos adversos , Leucopenia/cirugía , Síndromes Mielodisplásicos/inmunología , Inmunodeficiencia Combinada Grave/cirugía , Edad de Inicio , Niño , Preescolar , Femenino , Humanos , Recién Nacido , Leucopenia/inmunología , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/fisiopatología , Inmunodeficiencia Combinada Grave/inmunología , Quimera por TrasplanteRESUMEN
Reticular dysgenesis is an autosomal recessive form of human severe combined immunodeficiency characterized by an early differentiation arrest in the myeloid lineage and impaired lymphoid maturation. In addition, affected newborns have bilateral sensorineural deafness. Here we identify biallelic mutations in AK2 (adenylate kinase 2) in seven individuals affected with reticular dysgenesis. These mutations result in absent or strongly decreased protein expression. We then demonstrate that restoration of AK2 expression in the bone marrow cells of individuals with reticular dysgenesis overcomes the neutrophil differentiation arrest, underlining its specific requirement in the development of a restricted set of hematopoietic lineages. Last, we establish that AK2 is specifically expressed in the stria vascularis region of the inner ear, which provides an explanation of the sensorineural deafness in these individuals. These results identify a previously unknown mechanism involved in regulation of hematopoietic cell differentiation and in one of the most severe human immunodeficiency syndromes.