Anti-cyclic citrullinated peptide (CCP) antibody levels are associated with both susceptibility to and progression of rheumatoid arthritis (RA) in the Korean population, new research demonstrates.
The finding is reported by Churl Hyun Im (Seoul National University Hospital, Seoul, South Korea) and colleagues in the journal Rheumatology International and is based on a retrospective study that compared 226 patients with RA with 164 healthy controls.
All subjects were assessed for rheumatoid factor (RF), anti-CCP antibody, and shared epitope (SE) status, and underwent radiographic assessment of joint erosion.
As expected, SE was more frequently detected in RA patients than in controls (64.2% v 40.1%), with the most prevalent HLA subtype being DRB1 0405. The frequency of anti-CCP antibody was significantly higher in RA patients (85.6% vs 3.1%), as was the titer of serum anti-CCP antibody (28.6 U/ml vs 0.6 U/ml). RF was positive in 78.5% of RA patients.
Both SE and anti-CCP antibody were associated with RA susceptibility in unadjusted analyses. However, the association between SE and RA disappeared after adjusting for the presence of anti-CCP antibody, whereas anti-CCP was associated with RA even after adjusting for SE (odds ratio [OR]=179.9).
Anti-CCP antibody was also associated with radiographic erosion independently of SE or RF, with an OR of 3.9, while neither SE nor RF were associated with erosive changes.
“These findings suggest that anti-CCP antibody is more associated with the development of RA than SE,” write Im et al, who add that anti-CCP antibody is linked with tissue erosion rather than inflammatory processes.
They conclude: “Our results suggest that anti-CCP antibody is produced under certain autoimmune conditions, and that it is associated with bone and cartilage destruction processes in RA, independently of SE status and SE subtype.”
Free abstract