title: Efficacy of serum angiopoietin-1 measurement in the diagnosis of early rheumatoid arthritis.
abstract: OBJECTIVE
  Previous studies showed that angiopoietin-1(Ang-1) expression was increased in the synovium in early rheumatoid arthritis (RA) patients. The present study was therefore designed to examine whether determination of serum Ang-1 might be effective in diagnosis of early RA.
  
  
  METHODS
  One hundred and five serum samples of RA (21 males, 84 females) were studied for serum Ang-1 level. Serum samples were also collected from other collagen diseases, including 35 cases of SLE, 29 cases of systemic sclerosis, 16 cases of polymyositis/dermatomyositis. Serum samples were additionally obtained from 34 patients who visited our clinic for evaluation of symmetrical polyarthritis with morning stiffness. After one year of follow-up, those patients who satisfied the ACR 1987 classification criteria for RA were defined as 'early RA'. Serum Ang-1 levels were measured by sandwich ELISA using anti-angiopoietin-1 antibodies (both monoclonal and polyclonal antibodies). Serum anti-CCP antibody and rheumatoid factor (RF) were measured by ELISA and by laser nepherometry, respectively.
  
  
  RESULTS
  Serum Ang-1 in RA patients was significantly higher than those in other collagen diseases. Serum Ang-1 levels in 50 normal healthy individuals were 5.8 ± 0.31 pg/ml (mean ± SEM). There was no significant difference in CRP and serum RF at the first visit between early RA patients and non-RA patients, whereas serum Ang-1 levels at the first visit were significantly higher in early RA (58.7 ± 17.9 pg/ml [mean ± SEM]) than those in non-RA (8.2 ± 4.5 pg/ml). ROC analysis revealed that serum Ang-1 (cut-off 23.91 pg/ml) could diagnose early RA at sensitivity 57.1% and specificity 84.6%, providing comparable area under the curve (0.71, 95% CI: 0.54-0.88) to that of serum anti-CCP antibody (0.72, 95% CI: 0.53-0.92). There was no significant correlation between anti-CCP antibody and Ang-1.
  
  
  CONCLUSIONS
  These results indicate that serum Ang-1 is as useful a marker for the diagnosis of early RA as serum anti-CCP antibody.
authors: Department of Rheumatology and Infectious Diseases, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan. iskw-a@kitasato-u.ac.jp
authors: A
authors: A
authors: Ishikawa
authors: J
authors: J
authors: Okada
authors: K
authors: K
authors: Nishi
authors: S
authors: S
authors: Hirohata
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D042683:Angiopoietin-1 / Q000097:blood*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology; D001323:Autoantibodies / Q000097:blood; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D042241:Early Diagnosis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007564:Japan; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry; D010456:Peptides, Cyclic / Q000276:immunology; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D012217:Rheumatoid Factor / Q000097:blood; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors; D015854:Up-Regulation; D055815:Young Adult
chemical_list: C467630:ANGPT1 protein, human; D042683:Angiopoietin-1; D001323:Autoantibodies; D015415:Biomarkers; D007166:Immunosuppressive Agents; D010456:Peptides, Cyclic; D014409:Tumor Necrosis Factor-alpha; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor