Cyclic citrullinated peptide (CCP)

Cyclic citrullinated peptide (CCP) is a synthetic peptide used primarily as a diagnostic tool to detect anti-citrullinated protein antibodies (ACPAs) in patients suspected of having rheumatoid arthritis (RA). The peptide contains citrulline, a non-standard amino acid produced by the post-translational modification of arginine by peptidylarginine deiminase (PAD) enzymes. In the context of RA, the immune system loses tolerance to citrullinated self-proteins, leading to the production of highly specific autoantibodies. While CCP itself is not a therapeutic target for drug intervention, it serves as a critical biomarker for early diagnosis, prognosis, and monitoring of RA. Therapeutic strategies instead focus on the enzymes responsible for citrullination (PADs) or the broader inflammatory cascade triggered by the recognition of citrullinated antigens.

Other names

Citrullinated peptideCCP antigenSynthetic cyclic citrullinated peptide

Not applicable as CCP is a diagnostic antigen rather than a therapeutic target.