ABSTRACT
Objective To explore the significance of hidden rheumatoid factor-IgM(HRF-IgM),anti-cyclic citullinated peptide antibodies(anti-CCP),antikeratin antibodies(AKA)combined test in the diagnosis of juvenile idiopathic arthritis(JIA).Methods The anti-CCP and rheumatoid factors(RF)were tested by enzyme linked immunosorbent assay(ELISA)in serum samples from 60 children with JIA,27 systemic lupus erythematosus(SLE),18 kawaski diseases and 50 healthy children who were enrolled to serve as normal controls.Indirect immumofluorescence method was used to test AKA.Using the QAE-Sephadex-A50 to separate RF then tested HRF-IgM by ELISA.Results Positive anti-CCP were found in sera of 13 patients with JIA(21.7%)and specificity 96.8%.RF were found lower test both with the JIA and other groups(?2=0.17 P=0.68).The results of AKA were similar to the anti-CCP,they were both lower sensitivity and higher specificity.There were 65% sensitivity and 85.3% specificity in the HRF-IgM,and great significant difference in positive rate in JIA and other group(?2=40.22 P=0.0001).Conclusions JIA children in the studied series has a higher detection rate and value of HRF-IgM as compared to the other control groups.HRF-IgM,anti-CCP,AKA combined test in JIA can prove to be a valuable reference index for diagnosing suspected JIA children.
ABSTRACT
Objective To explore the early diagnostic significance of anti-cyclic citrullinated peptide(CCP) antibody and hidden rheumatoid factor immunoglobulin M(HRF-IgM) detected by ELISA in patients with juvenile rheumatoid arthritis(JRA). Methods The synthesized CCP was used as the antigen to detect anti-CCP antibody. Anti-CCP antibody and HRF-IgM were detected dynamically in 27 patients with early diagnosed JRA and their specificity and sensitivity were determined for early diagnosed JRA by calculating the positive predicting value (PPV) and negative predicting value (NPV). Results The total positive rate of anti-CCP antibody and HRF-IgM were 58.5 % and 65.0 % respectively in patients with JRA. The sensitivity of HRF-IgM was more predominant than that of anti-CCP antibody. There was a positive correlation between the positive rate of antibodies and the subtype of JRA. The specificity of anti-CCP antibody for predicting early JRA was superior to that of HRF-IgM. When using these two tests in combination, the PPV predicting rate of early JRA was 93.7 % . Conclusions Both anti-CCP antibody and HRF-IgM are elevated in patients with JRA, which show positive correlations with the subtype of the disease. The specificity of anti-CCP antibody testing is considerably higher for diagnosing early JRA, and when it was used together with HRF-IgM testing, the PPV for JRA can be raised further.