title: Autoimmune myopathies: autoantibodies, phenotypes and pathogenesis.
abstract: The different autoimmune myopathies-for example, dermatomyositis, polymyositis, and immune-mediated necrotizing myopathies (IMNM)-have unique muscle biopsy findings, but they also share specific clinical features, such as proximal muscle weakness and elevated serum levels of muscle enzymes. Furthermore, around 60% of patients with autoimmune myopathy have been shown to have a myositis-specific autoantibody, each of which is associated with a distinct clinical phenotype. The typical clinical presentations of the autoimmune myopathies are reviewed here, and the different myositis-specific autoantibodies, including the anti-synthetase antibodies, dermatomyositis-associated antibodies, and IMNM-associated antibodies, are discussed in detail. This Review also focuses on a newly recognized form of IMNM that is associated with statin use and the production of autoantibodies that recognize 3-hydroxy-3-methylglutaryl-coenzyme A reductase, the pharmacological target of statins. The contribution of interferon signaling to the development of dermatomyositis and the potential link between malignancies and the initiation of autoimmune myopathies are also assessed.
authors.affiliation: Department of Neurology, Johns Hopkins Bayview Medical Center, Johns Hopkins Myositis Center, Mason F. Lord Building Center Tower, Suite 4500, Baltimore, MD 21224, USA. USA. amammen@jhmi.edu
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Mammen
mesh_terms: D001323:Autoantibodies / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D001327:Autoimmune Diseases / Q000235:genetics / Q000276:immunology* / Q000473:pathology*; D001706:Biopsy; D003882:Dermatomyositis / Q000276:immunology / Q000473:pathology; D004576:Electromyography; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000009:adverse effects; D008025:Ligases / Q000276:immunology; D008279:Magnetic Resonance Imaging; D018908:Muscle Weakness / Q000209:etiology / Q000473:pathology; D018482:Muscle, Skeletal / Q000201:enzymology / Q000473:pathology; D009135:Muscular Diseases / Q000276:immunology* / Q000473:pathology*; D009220:Myositis / Q000473:pathology; D009369:Neoplasms / Q000453:epidemiology; D010641:Phenotype; D012306:Risk
chemical_list: D001323:Autoantibodies; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D008025:Ligases