title: Enhanced response to enzyme replacement therapy in Pompe disease after the induction of immune tolerance.
abstract: Pompe disease, which results from mutations in the gene encoding the glycogen-degrading lysosomal enzyme acid alpha -glucosidase (GAA) (also called "acid maltase"), causes death in early childhood related to glycogen accumulation in striated muscle and an accompanying infantile-onset cardiomyopathy. The efficacy of enzyme replacement therapy (ERT) with recombinant human GAA was demonstrated during clinical trials that prolonged subjects' overall survival, prolonged ventilator-free survival, and also improved cardiomyopathy, which led to broad-label approval by the U.S. Food and Drug Administration. Patients who lack any residual GAA expression and are deemed negative for cross-reacting immunologic material (CRIM) have a poor response to ERT. We previously showed that gene therapy with an adeno-associated virus (AAV) vector containing a liver-specific promoter elevated the GAA activity in plasma and prevented anti-GAA antibody formation in immunocompetent GAA-knockout mice for 18 wk, predicting that liver-specific expression of human GAA with the AAV vector would induce immune tolerance and enhance the efficacy of ERT. In this study, a very low number of AAV vector particles was administered before initiation of ERT, to prevent the antibody response in GAA-knockout mice. A robust antibody response was provoked in naive GAA-knockout mice by 6 wk after a challenge with human GAA and Freund's adjuvant; in contrast, administration of the AAV vector before the GAA challenge prevented the antibody response. Most compellingly, the antibody response was prevented by AAV vector administration during the 12 wk of ERT, and the efficacy of ERT was thereby enhanced. Thus, AAV vector-mediated gene therapy induced a tolerance to introduced GAA, and this strategy could enhance the efficacy of ERT in CRIM-negative patients with Pompe disease and in patients with other lysosomal storage diseases.
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Baodong
authors.initials: B
authors.lastname: Sun
authors.forename: Andrew
authors.initials: A
authors.lastname: Bird
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Young
authors.forename: Priya S
authors.initials: PS
authors.lastname: Kishnani
authors.forename: Y-T
authors.initials: YT
authors.lastname: Chen
authors.forename: Dwight D
authors.initials: DD
authors.lastname: Koeberl
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D015153:Blotting, Western; D002460:Cell Line; D000229:Dependovirus / Q000187:drug effects; D023381:Endpoint Determination; D004797:Enzyme-Linked Immunosorbent Assay; D006003:Glycogen / Q000378:metabolism; D006009:Glycogen Storage Disease Type II / Q000276:immunology* / Q000628:therapy*; D006801:Humans; D007108:Immune Tolerance / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects; D009206:Myocardium / Q000201:enzymology; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D000520:alpha-Glucosidases / Q000008:administration & dosage / Q000276:immunology* / Q000494:pharmacology
chemical_list: D000906:Antibodies; D011994:Recombinant Proteins; D006003:Glycogen; C509951:GAA protein, human; D000520:alpha-Glucosidases