A comparative study of IgG second- and third-generation anti-cyclic citrullinated peptide (CCP) ELISAs and their combination with IgA third-generation CCP ELISA for the diagnosis of rheumatoid arthritis.

To compare IgG anti-cyclic citrullinated peptide (CCP) enzyme-linked immunosorbent assays (ELISAs) of second (anti-CCP2) and third generations (anti-CCP3) for the diagnosis of rheumatoid arthritis (RA), an IgA CCP3 ELISA was also evaluated. Combinations of the use of the three tests were evaluated. Anti-CCP2 IgG, anti-CCP3 IgG, and anti-CCP3 IgA antibody levels were determined by ELISAs in the serum of 70 patients with rheumatoid arthritis, 34 patients with systemic lupus erythematosus (SLE), and 54 normal subjects.