Ex vivo gene therapy with lentiviral vectors rescues adenosine deaminase (ADA)–deficient mice and corrects their immune and metabolic defects
Alessandra Mortellaro, Raisa Jofra Hernandez, Matteo M. Guerrini, Filippo Carlucci, Antonella Tabucchi, Maurilio Ponzoni, Francesca Sanvito, Claudio Doglioni, Clelia Di Serio, Luca Biasco, Antonia Follenzi, Luigi Naldini, Claudio Bordignon, Maria Grazia Roncarolo, and Alessandro Aiuti
From the San Raffaele Telethon Institute for Gene Therapy (HSR-TIGET), Milan, Italy; Department of Medicina Interna, Scienze Endocrino Metaboliche e Biochimica, University of Siena, Italy; Pathology Unit, Department of Oncology, San Raffaele H Scientific Institute, Milan, Italy; University Statistics Centre for Biomedical Sciences, Università Vita-Salute San Raffaele, Milan, Italy; and Università Vita-Salute San Raffaele, Milan, Italy.
Adenosine deaminase (ADA) deficiency is caused by a purine metabolic dysfunction, leading to severe combined immunodeficiency (SCID) and multiple organ damage. To investigate the efficacy of ex vivo gene therapy with self-inactivating lentiviral vectors (LVs) in correcting this complex phenotype, we used an ADA–/– mouse model characterized by early postnatal lethality. LV-mediated ADA gene transfer into bone marrow cells combined with low-dose irradiation rescued mice from lethality and restored their growth, as did transplantation of wild-type bone marrow. Mixed chimerism with multilineage engraftment of transduced cells was detected in the long term in animals that underwent transplantation. ADA activity was normalized in lymphocytes and partially corrected in red blood cells (RBCs), resulting in full metabolic detoxification and prevention of severe pulmonary insufficiency. Moreover, gene therapy restored normal lymphoid differentiation and immune functions, including antigen-specific antibody production. Similar degrees of detoxification and immune reconstitution were obtained in mice treated early after birth or after 1 month of enzyme-replacement therapy, mimicking 2 potential applications for ADA-SCID. Overall, this study demonstrates the efficacy of LV gene transfer in correcting both the immunological and metabolic phenotypes of ADA-SCID and supports the future clinical use of this approach.
Prepublished online as a Blood First Edition Paper on July 11, 2006; DOI 10.1182/blood-2006-05-023507.