title: PUF60: a prominent new target of the autoimmune response in dermatomyositis and Sjögren's syndrome.
abstract: OBJECTIVE
  Autoantibodies are used clinically to phenotype and subset patients with autoimmune rheumatic diseases. We detected a novel 60 kDa autoantibody specificity by immunoblotting using a dermatomyositis (DM) patient's serum. Our objective was to identify the targeted autoantigen and to evaluate disease specificity and clinical significance of this new autoantibody.
  
  
  METHODS
  A new 60 kDa specificity was detected by immunoblotting HeLa cell lysates. The targeted autoantigen was identified as poly(U)-binding-splicing factor 60 kDa (PUF60) using (i) a human protein array and (ii) two-dimensional gel electrophoresis and liquid chromatography tandem mass spectrometry peptide sequencing. Anti-PUF60 antibodies were assayed by ELISA using sera from patients with primary Sjögren's syndrome (SS; n=84), systemic lupus erythematosus (SLE; n=71), DM (n=267), polymyositis (n=45), inclusion body myositis (n=45) and healthy controls (n=38).
  
  
  RESULTS
  PUF60 was identified as a new autoantigen. Anti-PUF60 antibodies were present in 25/84 (30%) patients with SS, 6/71 (8.5%) patients with SLE and 2/38 (5.0%) control subjects (SS vs controls, p=0.002; SLE vs controls, p=0.711). Anti-PUF60 antibodies were present in 48/267 (18.0%) patients with DM versus 4/45 (8.9%) and 5/45 (11.1%) patients with inclusion body myositis and polymyositis, respectively. The antibody was significantly associated with anti-Ro52 antibodies, rheumatoid factor and hyperglobulinemia in the patients with primary SS. In patients with DM, the antibody was associated with anti-transcription intermediary factor 1 gamma seropositivity and Caucasian race.
  
  
  CONCLUSIONS
  PUF60 represents a novel autoantigen in patients with SS and DM. PUF60 antibodies are associated with distinct clinical features and different immune responses in different diseases.
authors.affiliation: Department of Dermatology, Stanford University School of Medicine, Redwood City, California, USA.
authors.forename: David F
authors.initials: DF
authors.lastname: Fiorentino
authors.affiliation: Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Presby
authors.affiliation: Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Alan N
authors.initials: AN
authors.lastname: Baer
authors.affiliation: Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Petri
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Kerri E
authors.initials: KE
authors.lastname: Rieger
authors.affiliation: Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Soloski
authors.affiliation: Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Antony
authors.initials: A
authors.lastname: Rosen
authors.affiliation: Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA Muscle Disease Unit, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Mammen
authors.affiliation: Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Christopher-Stine
authors.affiliation: Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Livia
authors.initials: L
authors.lastname: Casciola-Rosen
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology; D015551:Autoimmunity; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003882:Dermatomyositis / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000072260:RNA Splicing Factors / Q000276:immunology*; D012097:Repressor Proteins / Q000276:immunology*; D012469:Salivary Glands / Q000276:immunology; D012859:Sjogren's Syndrome / Q000276:immunology*; D012867:Skin / Q000276:immunology
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D015415:Biomarkers; D000072260:RNA Splicing Factors; D012097:Repressor Proteins; C410595:poly-U binding splicing factor 60KDa
keywords: Autoantibodies; Dermatomyositis; Sjøgren's Syndrome; Systemic Lupus Erythematosus