PT  - JOURNAL ARTICLE
AU  - Nielen, M M J
AU  - van der Horst, A R
AU  - van Schaardenburg, D
AU  - van der Horst-Bruinsma, I E
AU  - van de Stadt, R J
AU  - Aarden, L
AU  - Dijkmans, B A C
AU  - Hamann, D
TI  - Antibodies to citrullinated human fibrinogen (ACF) have diagnostic and prognostic value in early arthritis
AID  - 10.1136/ard.2004.029389
DP  - 2005 Aug 01
TA  - Annals of the Rheumatic Diseases
PG  - 1199--1204
VI  - 64
IP  - 8
4099  - http://ard.bmj.com/content/64/8/1199.short
4100  - http://ard.bmj.com/content/64/8/1199.full
SO  - Ann Rheum Dis2005 Aug 01; 64
AB  - Background: The anti-cyclic citrullinated peptide (CCP) test has a high sensitivity and specificity for rheumatoid arthritis, although CCP is not the physiological target of the autoantibodies. Citrullinated fibrin is abundant in inflamed synoviumObjective: To assess the diagnostic and prognostic value of antibodies against citrullinated fibrinogen (ACF), a soluble precursor of fibrin, in comparison with IgM-rheumatoid factor (IgM-RF) and the second generation anti-CCP test.Methods: In 379 patients with early arthritis (258 rheumatoid and 121 undifferentiated), the sensitivity, specificity, and positive predictive value of ACF, anti-CCP, and IgM-RF for diagnosing rheumatoid arthritis were calculated. Multivariate logistic regression analysis was used to assess the diagnostic and prognostic value (radiographic progression after two years) of the tests.Results: The sensitivities of the ACF, anti-CCP, and IgM-RF tests were 55.8%, 57.8%, and 44.6%, with specificities of 92.6%, 94.2%, and 96.7%, respectively. Approximately 30% of the IgM-RF negative patients were positive for ACF or anti-CCP or both. The ACF and anti-CCP test had a high agreement in early arthritis (κ = 0.84). Of all baseline characteristics, the ACF test and the anti-CCP test were the best predictors for diagnosing rheumatoid arthritis at one year (odds ratio (OR) = 10.3 and 10.6, respectively) and for radiographic progression after two years (OR = 12.1 and 14.8).Conclusions: ACF is as sensitive as anti-CCP and more sensitive than IgM-RF in diagnosing rheumatoid arthritis in early arthritis. The ACF test is also a good predictor of radiographic progression, with a performance similar to the anti-CCP test. The ACF test and the anti-CCP test are especially valuable in IgM-RF negative arthritis.