RESUMO
Objective To evaluate the distribution and significance of IgG subclasses of anti-cyclic cirullinated peptide antibody (anti-CCP) in sera from patients with rheumatoid arthritis (RA).Methods A total of 83 patients with RA at the Department of Endocrinology of Taizhou Hospital , 51 disease controls and 50 healthy controls during the period from August 2012 to June 2013 were enrolled.The total serum IgG and IgG subclasses of anti-CCP antibodies were detected by antigen specific enzyme linked immune-sorbent assay( ELISA ).The prevalence and relative amount of IgG subclasses were calculated and compared.Statistical analysis was performed by χ2 test and Kruskal-Wallis H test.Results The positive rates of IgG subclasses of anti-CCP were anti-IgG 71.1%(59/83), anti-IgG1 78.3%(65/83), anti-IgG2 26.5%(22/83), anti-IgG3 60.2%(50/83), anti-IgG4 74.7%(62/83) respectively.The diagnostic value of anti-CCP-IgG1, anti-CCP-IgG3 and anti-CCP-IgG4 alone or combined (AUC =0.818-0.901),compared with anti-CCP-IgG(AUC=0.857), had no significant difference(Z=0.028-0.045,P>0.05).The DAS28 score of anti-CCP-IgG1(DAS28 =6.5), and anti-CCP-IgG4(DAS28 =6.5)positive in patients with RA were significantly higher than those in negative groups (DAS28=4.5,4.6)(U=396.0,427.5,P<0.01).The T28(T28=4.0,4.0)and SW28(SW28=4.0,4.0) results of CCP-IgG1and CCP-IgG4 positive in patients with RA were significantly higher than those in negative groups (T28=3.0,3.0,SW28 =3.0,3.0)(U=377.5,406.0,255.5,286.5,P<0.05).Conclusions The distribution of IgG subclasses of anti-CCP in sera from patients with RA was predominantly anti-CCP-IgG1, anti-CCP-IgG3 and anti-CCP-IgG4 associated with RA disease activity.However , whether joint detection of IgG subclasses can replace conventional anti -CCP is questionable.