A117: Demonstration of Antibodies to Multiple Citrullinated Epitopes in the Sera of Patients With Juvenile Idiopathic Arthritis

Background/Purpose: IgG anti-cyclic citrullinated peptide (anti-CCP) antibodies have been identified in the sera of juvenile idiopathic arthritis (JIA) patients and have been associated with more destructive disease. The identity of the target proteins of the citrullinated modification has remained elusive. We attempted to determine the prevalence and significance of different citrullinated epitopes. Methods: We evaluated serum from 96 patients with various subtypes of JIA for the presence of antideiminated (citrullinated) fibrinogen, anti-citrullinated α-enolase, anti-citrullinated and native type II collagen, and anti-vimentin (vim1–16 and vim 59–74) antibodies by enzyme-linked immunosorbent assays. We correlated the presence of the antibodies with anti-CCP and rheumatoid factor (RF) isotypes, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels. Results: 31 JIA patients (32%) demonstrated reactivity to anti-citrullinated fibrinogen, 23 (24%) to anti-citrullinated type II collagen, 10 (10.5%) to anticitrullinated vimentin I-16, 9 (9%) to anti-citrullinated α-enolase, and 7 (7.4%) to anti-citrullinated vimentin 59–74 antibodies. One IgM RF positive JIA patient was positive for all 6 of the citrullinated autobodies assayed. The reactivity was higher in those JIA patients positive for IgM RF and IgG/IgM anti-CCP antibodies. Conclusion: The study demonstrates that antibodies to multiple citrullinated epitopes are present in the sera of patients with JIA. A higher percentage of antibodies reacted with citrullinated fibrinogen and citrullinated type II collagen. The more widespread the positivity correlates with more severe disease.