Cyclical Citrullinated Peptide (CCP)

"Cyclic citrullinated peptide" is also known as "CCP". It is a cyclic peptide incorporating the amino acid citrulline.a synthetic peptide that functions as a target for autoantibodies with a very high specificity for rheumatoid arthritis.Cyclic peptides (or cyclic proteins) are polypeptide chains whose amino and carboxyl termini are themselves linked together with a peptide bond, forming a circular chain. Amino acids are molecules containing an amine group, a carboxylic acid group and a side chain that varies between different amino acids.

Recently it was determined that AKA recognize an epitope that contains citrulline, the deiminated form of arginine.5 IgG antibodies against a synthetic peptide containing citrulline known as CCP (Cyclic Citrullinated Peptide) has proven to be superior to either AKA or RF testing in differentiating RA from other autoimmune diseases. The presence of CCP antibody occurs independently of elevated RF levels in patients with RA.