What is the Difference Between Anti-CCP and ACPA?

Anti-CCP and ACPA are both autoantibodies that target citrullinated proteins and are used for the early detection of rheumatoid arthritis (RA). However, there are some differences between the two:

1. Specificity: Anti-CCP (anti-cyclic citrullinated peptide) antibodies are a subset of ACPA (anti-citrullinated protein antibodies) and are not completely cross-reactive with other citrullinated proteins. ACPA is a broader term than anti-CCP antibody.
2. Detection: The anti-CCP test detects anti-CCP autoantibodies, while the ELISA test detects ACPA autoantibodies.
3. Citrullinated Proteins: Anti-CCP antibodies are directed against citrullinated proteins, while ACPAs are directed against peptides and proteins that are citrullinated.

Both anti-CCP and ACPA are used for the early detection of RA because they can be present in patients years before the onset of the disease and are associated with a more severe disease course. The specificity of anti-CCP for RA is 88–98%. ACPAs can form immune complexes, which can activate the complement system and release chemotactic factors.

Comparative Table: Anti-CCP vs ACPA

Anti-CCP and ACPA are both types of autoantibodies associated with rheumatoid arthritis (RA). Here is a table comparing the differences between them:

Both anti-CCP and ACPA are citrullinated proteins and can be used for the early detection of RA. The key difference between the two is that anti-CCP is a subset of ACPA and is more specific in targeting cyclic citrullinated peptides, while ACPA is a broader category of autoantibodies that target various citrullinated proteins.