To assess the value of rheumatoid factors IgM-RF, IgA-RF, IgG-RF, interleukin-1 receptor type I (IL-1RI) and cyclin-dependent kinase 2 (CDK2) in the diagnosis of rheumatoid arthritis (RA).
IgM-RF, IgA-RF, IgG-RF, IL-1RI and CDK2 were detected in 47 patients with active RA, 47 with inactive RA, 20 with active systemic lupus erythematosus (SLE), 20 with inactive SLE, 20 with acute upper respiratory tract infection (AURTI), and 20 healthy controls using enzyme-linked immunosorbent assay (IgM-RF, IgA-RF, IgG-RF, IL-1RI) and time-resolved fluoroimmunoassay (CDK2).
Patients with active and inactive RA showed significant differences in peripheral serum CDK2 and IgA-RF levels (P<0.05). Between active and inactive RA patients, RA patients and SLE patients, RA patients and AURTI patients, and RA patients and the control subjects, the area under curve (AUC) of the receiver operating characteristic curve (ROC) was 0.561, 0.814, 0.799, and 0.888 for IgM-RF, 0.596, 0.678, 0.729, and 0.850 for IgA-RF, 0.614, 0.718, 0.692, and 0.791 for IgG-RF, 0.646, 0.691, 0.762, and 0.835 for IL-1RI, 0.803, 0.753, 0.741, and 0.840 for CDK2, respectively.
IgM-RF may have high value in the diagnosis and differential diagnosis of RA, and CDK2 can be useful for differential diagnosis between active and inactive RA.