title: Novel antibody associations in immune-mediated necrotising myopathy without inflammation.
abstract: BACKGROUND
  The patient presenting with proximal muscle weakness, elevated serum creatinine kinase and myopathic electromyography and biopsy findings has a wide differential diagnosis that includes toxic, autoimmune, paraneoplastic and congenital myopathies. Autoimmune myopathies are important to identify because they may respond to immunosuppressive therapies.
  
  
  METHODS
  We describe two cases of immune-mediated necrotizing myopathy each associated with a novel antibody.
  
  
  RESULTS
  Case 1 describes a progressive myopathy in a statin user. Antibodies to 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase were identified and the patient responded to steroid therapy. Case 2 describes an aggressive myopathy associated with antibodies to signal recognition particle. There was no response to steroids. Clinical improvement followed treatment with rituximab and cyclophosphamide.
  
  
  CONCLUSIONS
  The identification of myositis-specific antibodies is important because they are associated with distinct clinical phenotypes and may guide the physician in terms of treatment strategies.
authors.affiliation: Dublin Neurological Institute at the Mater Misericordiae University Hospital, 57 Eccles St., Dublin 7, Ireland. Denis.Curtin@physicians.ie.
authors.forename: D
authors.initials: D
authors.lastname: Curtin
authors.affiliation: Department of Neurology, Mater Private Hospital, Dublin, Ireland.
authors.forename: D
authors.initials: D
authors.lastname: Costigan
authors.affiliation: Department of Rheumatology, Mater Private Hospital, Dublin, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: McCarthy
authors.affiliation: Department of Neuropathology, Beaumont Hospital, Dublin, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Jansen
authors.affiliation: Department of Neuropathology, Beaumont Hospital, Dublin, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Farrell
authors.affiliation: Department of Clinical Neurophysiology, Mater Misericordiae University Hospital, Dublin, Ireland.
authors.forename: V
authors.initials: V
authors.lastname: Reid
authors.affiliation: Dublin Neurological Institute at the Mater Misericordiae University Hospital, 57 Eccles St., Dublin 7, Ireland.
authors.forename: K
authors.initials: K
authors.lastname: O'Rourke
mesh_terms: D000214:Acyl Coenzyme A / Q000276:immunology; D000368:Aged; D001323:Autoantibodies / Q000097:blood; D001327:Autoimmune Diseases / Q000276:immunology*; D003520:Cyclophosphamide / Q000627:therapeutic use; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000276:immunology; D009135:Muscular Diseases / Q000188:drug therapy / Q000276:immunology*; D009220:Myositis / Q000276:immunology; D000069283:Rituximab / Q000627:therapeutic use; D013256:Steroids / Q000627:therapeutic use
chemical_list: D000214:Acyl Coenzyme A; D001323:Autoantibodies; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D013256:Steroids; C015901:glutaryl-coenzyme A; D000069283:Rituximab; D003520:Cyclophosphamide
keywords: 3-Hydroxy-3-methyl-glutaryl-CoA reductase inhibitor; Antibody; Immune mediated; Necrotizing myopathy; Signal recognition particle