PT  - JOURNAL ARTICLE
AU  - W H Bos
AU  - J Ursum
AU  - N de Vries
AU  - G M Bartelds
AU  - G J Wolbink
AU  - M T Nurmohamed
AU  - I E van der Horst-Bruinsma
AU  - R J van de Stadt
AU  - J B A Crusius
AU  - P P Tak
AU  - B A C Dijkmans
AU  - D van Schaardenburg
TI  - The role of the shared epitope in arthralgia with anti-cyclic citrullinated peptide antibodies (anti-CCP), and its effect on anti-CCP levels
AID  - 10.1136/ard.2008.089953
DP  - 2008 Sep 01
TA  - Annals of the Rheumatic Diseases
PG  - 1347--1350
VI  - 67
IP  - 9
4099  - http://ard.bmj.com/content/67/9/1347.short
4100  - http://ard.bmj.com/content/67/9/1347.full
SO  - Ann Rheum Dis2008 Sep 01; 67
AB  - Objectives: Patients presenting with both arthralgia and antibodies to cyclic citrullinated peptide (anti-CCP) have an increased risk of developing rheumatoid arthritis (RA). To further characterise this patient group and shed more light on its relationship with clinically manifest early arthritis and established RA, an immunogenetic and serological analysis was performed.Methods: In a group of 111 patients with anti-CCP-positive arthralgia, anti-CCP levels and shared epitope (SE) status were determined. Data were compared with 125 and 128 patients with anti-CCP-positive early arthritis and established RA respectively.Results: In patients with anti-CCP-positive arthralgia, the frequency of SE allele positivity is significantly lower when compared with anti-CCP-positive early arthritis and established RA (58% vs 80%, and 58% vs 92%, respectively, both p<0.001). Median anti-CCP levels were higher in the group of patients with SE-positive arthralgia compared with the group of patients with SE-negative arthralgia (p = 0.02). Median anti-CCP levels were similar in the groups of patients with SE-positive arthralgia and arthritis.Conclusions: The lower frequency of SE positivity in patients with arthralgia compared with patients with RA indicates that, compared with patients who were SE positive, patients who were SE negative as a group go through a longer arthralgia phase, or alternatively have a lower risk for transition from anti-CCP positive arthralgia to RA. Furthermore, the present results suggest that in this early stage the effect of the SE on disease risk may be mediated through higher anti-CCP levels.