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.