The diagnostic significance of anti-cyclic citrullinated peptide 3.1 IgG/IgA antibody in patients with rheumatoid arthritis / 中华风湿病学杂志

ABSTRACT

Objective To explore the diagnostic value of anti-cyclic citrullinated peptide (CCP) 3.1 IgG/IgA antibody detected by enzyme-linked immunosorbent assay (ELISA) in patients with rheumatoid arthritis (RA).Methods The ELISA was used to measure the anti-CCP3.1 antibody in the serum of 169 RA patients,100 patients with other rheumatic diseases (including systemic lupus erythematosus,Sjogren's syndrome and osteoarthritis) and 72 healthy controls.The diagnostic value of CCP3.1 was assessed and compared with the second generation of anti-CCP IgG (CCP2) antibody,the correlations between anti-CCP3.1 antibody and the clinical and laboratory parameters were analyzed.Two-independent samples t test,chi-square test and Spearman's correlation were adopted for statistical analysis.Results ① The average cut-off concentration of anti-CCP3.1 antibody was (1122±1429) U/ml in RA,(13±14) U/ml in other rheumatic diseases and (6±5) U/ml in healthy controls.② The area under curve of ROC for anti-CCP3.1 antibody and anti-CCP2 antibody were 0.923 and 0.936 respectively.There was no difference between the sensitivity (82％ vs 79％)and specificity (97％ vs 99％) of anti-CCP3.1 antibody and anti-CCP2 antibody.The Kappa values between anti-CCP3.1 antibody and anti-CCP2 antibody was 0.763.③ We also found that anti-CCP3.1 antibody was positive in 20％(7/35) of anti-CCP2 antibody negative,43％(18/42) of RF negative,62％(47/76) of AKA negative,71％(49/69) of APF negative and 13％ of autoantibodies negative patients,indicated that antiCCP3.1 antibody had a potential value in the diagnosis of serum negative patients with RA.④ The presence of anti-CCP3.1 antibody was correlated with RF,HRF-IgG,APF,AKA,GPI and IgA (P＜0.05),except disease activity.Conclusion The sensitivity of anti-CCP3.1 antibody is slightly higher than anti-CCP2 antibody.The Anti-CCP3.1 antibody is a very valuable parameter for the diagnosis of RA,especially in serum negative patients.