Background: To determine the prevalence and significance of anti-citrullinated vimentin and anti-citrullinated type II collagen antibodies and elucidate their role in the disease process of juvenile idiopathic arthritis (JIA).
Methods: Sera were obtained from 95 patients with various subtypes of JIA, 19 systemic lupus erythematosus (SLE) patients, and 10 healthy children. Antibodies were measured in the sera against citrullinated and native type II collagen and vimentin (vim1-16 and vim 59-74) by enzyme-linked immunosorbent assay. Samples were compared to anti-cyclic citrullinated peptide (anti-CCP) antibody and rheumatoid factor (RF) isotypes, and our previously measured anti-citrullinated fibrinogen and α-enolase antibodies on the same patient population, in addition to erythrocyte sedimentation rate and C-reactive protein. The relationship between the anti-citrullinated antibody profile and disease activity and joint damage were also investigated.
Results: Twenty-three JIA patients (24%) demonstrated reactivity to anti-citrullinated type II collagen. Ten JIA patients (10.5%) demonstrated reactivity to anti-citrullinated vimentin 1-16 antibodies and 7 (7.4%) to anti-citrullinated vimentin 59-74 antibodies. One IgM RF-positive polyarticular patient was positive for all 5 of the citrullinated autoantibodies tested. Thirty-seven different subsets of patients were identified based on their anti-citrullinated autoantibody and RF isotype profile. No significant associations were noted with anti-citrullinated type II collagen and anti-citrullinated vimentin antibodies with joint damage or disease activity. Anti-citrullinated vimentin 59-74 antibodies demonstrated the highest overall specificity at 89.7%, with anti-citrullinated vimentin 1-16 and anti-citrullinated type II collagen antibodies at 86.2%.
Conclusion: This study demonstrates that antibodies to multiple citrullinated epitopes are present in the sera of patients with various subtypes of JIA. It also demonstrates the frequent occurrence of anti-citrullinated type II collagen and anti-citrullinated fibrinogen antibodies. The presence of autoantibodies to citrullinated antigens in JIA patients is highly diverse.