title: Clinical features of anti-TIF1-α antibody-positive dermatomyositis patients are closely associated with coexistent dermatomyositis-specific autoantibodies and anti-TIF1-γ or anti-Mi-2 autoantibodies.
abstract: OBJECTIVE
  Myositis-specific autoantibodies (MSAs), which characterize certain forms of inflammatory myopathy, are useful in the diagnosis and prediction of prognosis in DM/PM. Anti-transcriptional intermediary factor 1-α (TIF1-α) antibodies were recently reported to be associated with cancer-associated DM in conjunction with anti-TIF1-γ antibodies. This study aimed to identify a subset of DM patients who have anti-TIF1-α antibodies by using biotinylated recombinant proteins and to clarify the clinical and other serological features of DM patients with these antibodies.
  
  
  METHODS
  Sera from 202 Japanese patients with CTDs, including 108 with DM and 20 healthy controls, were screened for anti-TIF1-α antibodies by our novel ELISAs. Positive sera were further examined by immunoprecipitation and also investigated for the detection of anti-TIF1-γ and anti-Mi-2 antibodies.
  
  
  RESULTS
  Sera from 12 patients with DM were confirmed to be positive for anti-TIF1-α antibodies. None of the patients with other CTDs and none of the healthy controls had the antibodies. Seven anti-TIF1-α-positive patients simultaneously had anti-TIF1-γ antibodies and the other five had anti-Mi-2 antibodies, both of which are well known to be MSAs. These double-positive patients with anti-TIF1-α and anti-γ antibodies included three JDM and two cancer-associated adult DM patients, whereas all the double-positive patients with anti-TIF1-α and anti-Mi-2 antibodies were classical adult DM.
  
  
  CONCLUSIONS
  Although MSAs have been regarded as mutually exclusive, anti-Mi-2 antibody-positive patients simultaneously have anti-TIF1-α antibodies. Anti-Mi-2 antibody-positive patients are associated with classical DM without cancer even with the simultaneous presence of anti-TIF1-α antibodies.
authors.affiliation: Division of Connective Tissue Disease and Autoimmunity, Department of Dermatology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan. ymuro@med.nagoya-u.ac.jp
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Muro
authors.forename: Asuka
authors.initials: A
authors.lastname: Ishikawa
authors.forename: Kazumitsu
authors.initials: K
authors.lastname: Sugiura
authors.forename: Masashi
authors.initials: M
authors.lastname: Akiyama
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D001324:Autoantigens / Q000276:immunology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003882:Dermatomyositis / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D047468:Immunoprecipitation; D007223:Infant; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000276:immunology*; D011994:Recombinant Proteins; D014157:Transcription Factors / Q000276:immunology*; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; C045760:Mi-2 antibodies; D009687:Nuclear Proteins; D011994:Recombinant Proteins; C511956:TRIM33 protein, human; D014157:Transcription Factors; C093517:transcriptional intermediary factor 1