Efficacy of serum angiopoietin-1 measurement in the diagnosis of early rheumatoid arthritis

CER4325
2011 Vol.29, N°4
PI 0604, PF 0608
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PMID: 21906428 [PubMed]

Received: 23/11/2010
Accepted : 14/02/2011
In Press: 30/08/2011
Published: 30/08/2011

Abstract

OBJECTIVES:
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.