title: [Autoantibody profile in myositis].
abstract: Patients suffering from muscular symptoms or with an increase of creatine kinase levels may present a myopathy. In such situations, clinicians have to confirm the existence of a myopathy and determine if it is an acquired or a genetic muscular disease. In the presence of an acquired myopathy after having ruled out an infectious, a toxic agent or an endocrine cause, physicians must identify which type of idiopathic myopathy the patient is presenting: either a myositis including polymyositis, dermatomyositis, and inclusion body myositis, or an immune-mediated necrotizing myopathy. Histopathology examination of a muscle biopsy is determinant but detection of autoantibody is now also crucial. The myositis-specific antibodies and myositis-associated antibodies lead to a serologic approach complementary to the histological classification, because strong associations of myositis-specific antibodies with clinical features and survival have been documented. The presence of anti-synthetase antibodies is associated with an original histopathologic pattern between polymyositis and dermatomyositis, and defines a syndrome where interstitial lung disease drives the prognosis. Anti-MDA-5 antibody are specifically associated with dermatomyositis, and define a skin-lung syndrome with a frequent severe disease course. Anti-TIF1-γ is also associated with dermatomyositis but its presence is frequently predictive of a cancer association whereas anti-MI2 is associated with the classical dermatomyositis. Two specific antibodies, anti-SRP and anti-HMGCR, are observed in patients with immune-mediated necrotizing myopathies and may be very useful to distinguish acquired myopathies from dystrophic muscular diseases in case of a slow onset and to allow the initiation of effective therapy.
authors.affiliation: Équipe Inserm U974, DHUI2B, UPMC, service de médecine interne, centre de référence des maladies neuromusculaires Paris Est, groupe hospitalier de la Pitié-Salpêtrière, AP-HP, 83, boulevard de l'Hôpital, 75013 Paris, France. Electronic address: yves.allenbach@psl.aphp.fr.
authors.forename: Y
authors.initials: Y
authors.lastname: Allenbach
authors.affiliation: Équipe Inserm U974, DHUI2B, UPMC, service de médecine interne, centre de référence des maladies neuromusculaires Paris Est, groupe hospitalier de la Pitié-Salpêtrière, AP-HP, 83, boulevard de l'Hôpital, 75013 Paris, France.
authors.forename: O
authors.initials: O
authors.lastname: Benveniste
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology*; D001327:Autoimmune Diseases / Q000145:classification* / Q000175:diagnosis* / Q000276:immunology; D003937:Diagnosis, Differential; D006801:Humans; D018482:Muscle, Skeletal / Q000473:pathology; D009220:Myositis / Q000145:classification* / Q000175:diagnosis* / Q000276:immunology
chemical_list: D001323:Autoantibodies; D001324:Autoantigens
keywords: Auto-anticorps; Autoantibodies; Myopathie nécrosante auto-immune; Myosite; Myositis; Necrotizing myopathy