What is the Difference Between Anti-CCP and ACPA

The key difference between anti-CCP and ACPA is that anti-CCP is a subset of ACPA useful as an autoantibody marker to detect patients with rheumatoid arthritis, while ACPA is a major category of autoantibodies.

Autoantibodies are a type of antibody produced by the immune system of the body against its own proteins. This usually occurs during inflammatory reactions. Such conditions are common in rheumatoid arthritis. Autoantibodies lead to autoimmune diseases where the body’s immune system attacks itself due to misinterpretation of antigens. ACPA and Anti-CCP are two such types of autoantibodies, which consist of many common characteristics. These two autoantibodies play a major role in the early detection of rheumatoid arthritis.

1. Overview and Key Difference
2. What is Anti-CCP
3. What is ACPA
4. Similarities – Anti-CCP and ACPA
5. Anti-CCP vs ACPA in Tabular Form
6. Summary – Anti-CCP and ACPA

What is Anti-CCP?

Anti-CCP or anti-cyclic citrullinated peptides are a type of autoantibodies that provide a sign of rheumatoid arthritis. They are a subset of ACPA and are not completely cross-reactive with other citrullinated proteins. Anti-CCP targets healthy tissues in the joints and induces rheumatoid arthritis. It is a progressive autoimmune disease that causes pain and swelling in the joints. Clinically it was found that 75 percent of the patients suffering from rheumatoid arthritis have anti-CCP in their blood.

Figure 01: Rheumatoid Arthritis

Anti-CCP test helps to diagnose rheumatoid arthritis and the level of progression. This is usually done along with a rheumatoid factor (RF) test. However, the presence of RF does not confirm the development of rheumatoid arthritis since RF factors are common to other autoimmune diseases and healthy individuals. Anti-CCP provides a highly accurate diagnosis of rheumatoid arthritis compared with RF testing.

What is ACPA?

ACPA or anti-citrullinated protein antibodies direct against the detection of citrullinated proteins and peptides. ACPAs are autoantibodies, meaning that they are antibodies to an individual’s own proteins. ACPAs are found in patients suffering from rheumatoid arthritis. Hence, it is a powerful biomarker to diagnose the disease condition at very early stages. In clinical terms, immunologists use cyclic citrullinated peptides (CCP) to detect ACPAs in patient serum and plasma.

During an inflammatory reaction such as rheumatoid arthritis, arginine amino acid residues have the potential to get converted to citrulline residues enzymatically in proteins like vimentin. This process of conversion is citrullination. During citrullination, if the protein structure gets drastically altered, the individuals’ immune system will detect these altered proteins as antigens and generate an immune response. This immune response is an autoimmune response, which leads to autoimmune diseases.

What are the Similarities Between Anti-CCP and ACPA?

Anti-CCP and ACPA are autoantibodies.
Both types are produced by the individuals’ immune systems.
They target individuals’ own proteins.
Moreover, both can act as biomarkers.
Both are citrullinated proteins.
Anti-CCP and ACPA are used for the early detection of rheumatoid arthritis.
Anti-CCP and ACPA are detected in the same sera.

What is the Difference Between Anti-CCP and ACPA?

The key difference between anti-CCP and ACPA is that anti-CCP is a subset of ACPA that includes autoantibodies, while ACPA is a major category of autoantibodies. Anti-CCP stands for anti-cyclic citrullinated peptide, while ACPA stands for anti-citrullinated protein antibodies. Moreover, the anti-CCP test detects anti-CCP autoantibodies, while the ELISA test detects ACPA autoantibodies.

The below infographic presents the differences between anti-CCP and ACPA in tabular form for side by side comparison.

Summary – Anti-CCP vs ACPA

Autoantibodies are a type of antibodies produced by the immune system of the body against its own proteins during inflammatory reactions. Anti-CCPs (anti-cyclic citrullinated peptides) are a type of autoantibodies that provide a sign of rheumatoid arthritis. They are a subset of ACPA and are not completely cross-reactive with other citrullinated proteins. ACPA or anti-citrullinated protein antibodies direct against the detection of citrullinated proteins and peptides. So, this is the key difference between anti-CCP and ACPA. Both anti-CCP and ACPA are used for early detection of rheumatoid arthritis since they function as powerful biomarkers.