title: [Clinical features and misdiagnosis of anti-Jo-1 syndrome: analysis of 33 cases].
abstract: OBJECTIVE
  To evaluate the clinical features and causes of misdiagnosis of anti-Jo-1 syndrome.
  
  
  METHODS
  The data of 33 polymyositis (PM)/dermatomyositis (DM) patients with anti-Jo-1 antibody hospitalized from January 1997 to June 2002 in Peking Union Medical College Hospital were reviewed retrospectively. The initial symptom, clinical and laboratory characteristics, diagnosis, efficacy of therapy and follow-up were studied.
  
  
  RESULTS
  51.5% of the patients developed lung impairment and 24.2% of the patients developed arthritis/arthralgia before the onset of PM/DM, only 5 patients had the typical rash, and/or myalgia and muscle weakness as the initial symptoms (15.2%). Patients with anti-Jo-1 syndrome were usually misdiagnosed as with rheumatoid arthritis (27.3%), idiopathic pulmonary fibrosis (12.1%), and pneumonia (15.2%). Anti-Jo-1 syndrome was associated with inflammatory myositis (100%), interstitial lung disease (ILD) (93.9%), fever (60.6%), polyarthritis/polyarthralgia (54.5%), Raynaud's phenomenon (21.2%), and sclerodactyly (21.2%). The muscle symptom was relatively mild and the symptom of ILD was relatively severe. Treatment of corticosteroid plus immunosuppressive drugs was effective in achieving initial remission, while relapse was frequent.
  
  
  CONCLUSIONS
  Few patients with anti-Jo-1 syndrome have the episode of classical myositis as initial symptom. Lung impairment, especially ILD, and joint involvement are more common in early phase of the disease.
authors.affiliation: Department of Rheumatology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing 100730, China.
authors.forename: Wen-Jie
authors.initials: WJ
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Fu-Lin
authors.initials: FL
authors.lastname: Tang
mesh_terms: D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood*; D003951:Diagnostic Errors; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009220:Myositis / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology*; D013577:Syndrome
chemical_list: D000974:Antibodies, Antinuclear; C046750:Jo-1 antibody