Clinical Significance of Anti-Cyclic Citrullinated Peptide Antibodies and IgM Rheumatoid Factor in Rheumatoid Arthritis Patients

Objectives : To evaluate the clinical significances of antibodies to cyclic citrullinated peptides (anti-CCP) and IgM Rheumatoid Factor(RF) in patients with established rheumatoid arthritis. Methods : The subjects included 86 established RA patients according to the revised ACR criteria and 46 non-RA patients presenting joint manifestations and 61 healthy individuals as control. Anti-CCP and IgM RF were measured by ELISA and nephelometric method, respectively. Results : The sensitivity and specificity of anti-CCP were 64% and 98% and of IgM RF were 69% and 76%, respectively. Eleven(41%) out of 27 sero-negative RA patients had elevated antiCCP. Combination of anti-CCP with IgM RF increased diagnostic sensitivity and specificity of RA to 81% and 99%, respectively. Conclusion : Simultaneous measurement of IgM RF and anti-CCP for the initial evaluation of arthritis would increase the diagnostic efficacy of RA.