Abstract:

Objective To investigate the clinical significance of serum anti-cyclic citrullinated peptide (anti-CCP) antibodies in diagnosis of juvenile idiopathic arthritis (JIA). Methods Serum anti-CCP antibodies of 68 children suspected of JIA with fever and arthritis of unknown causes were determined by ELISA, and comprehensive analysis was carried out with clinical data and related laboratory findings. Results Among the 68 children suspected of JIA, there were 10 cases of polyarticular JIA, 13 cases of systemic onset JIA, 8 cases of oligoarticular JIA and 13 cases of enthesitis related JIA. There were 11 cases of other rheumatoid diseases, 8 cases of neoplastic diseases of blood and 5 cases of infectious diseases. The serum anti-CCP level in children suspected of polyarticular JIA was significantly higher than those in children suspected of systemic onset JIA, oligoarticular JIA and enthesitis related JIA (P<0.05). With serum anti-CCP≥15.8 RU/mL as the positive threshold value, the area under receiver operating characteristic curve was 0.80, and the sensitivity and specificity in diagnosis of polyarticular JIA were 80% and 67.6% respectively. The serum anti-CCP level was positively related to serum C-reaction protein level in children suspected of polyarticular JIA (r=0.764, P=0.017). Conclusion Serum anti-CCP can be used for the diagnosis of polyarticular JIA, and 15.8 RU/mL may be a suitable cut-off level.

Key words: anti-cyclic citrullinated peptide antibodies, juvenile idiopathic arthritis, receiver operating characteristic curve, diagnosis