Anti-cyclic citrullinated peptide (anti-CCP) is an antibody present in most rheumatoid arthritis patients. Levels of anti-CCP can be detected in a patient through a blood test. A positive anti-CCP test result can be used in conjunction with other blood tests, imaging tests, and physical examinations to reach a rheumatoid arthritis diagnosis.
A patient with rheumatoid arthritis who tests positive for anti-CCP in their blood has what’s known as seropositive rheumatoid arthritis. This is as opposed to someone who has been diagnosed with rheumatoid arthritis but tests negative for anti-CCP antibodies and/or rheumatoid factor.
A positive anti-CCP test result in rheumatoid arthritis patients can be used as a prognostic tool to determine the severity of symptoms the patient may have throughout the disease course. Anti-CCP positive patients can potentially experience a more aggressive disease course. However, this can also depend on many different factors and varies from patient to patient. The prognosis of anti-CCP positive patients also depends greatly on early diagnosis of rheumatoid arthritis and how soon treatment can begin.
Anti-CCP is an autoantibody produced by the patient’s immune system that attacks the body. These attacks can produce inflammatory symptoms most commonly experienced in rheumatoid arthritis.
Testing for the presence of anti-CCP is a relatively new support tool in helping doctors diagnose rheumatoid arthritis. Prior to the discovery of anti-CCP and the testing of it, most doctors used rheumatoid factor – another antibody – as a test to help reach a rheumatoid arthritis diagnosis.
Anti-CCP is thought to be present in 60% to 70% of patients with rheumatoid arthritis. Anti-CCPs can also exist in a patient for years before they ever develop clinical rheumatoid arthritis symptoms.
Anti-CCP positive testing is also used to help doctors deliver a prognosis because many anti-CCP positive patients experience severe rheumatoid arthritis symptoms. Testing positive for anti-CCP also helps doctors pursue specific treatment options.
The specific cause of developing anti-CCP antibodies in patients is unknown although it is thought to be a combination of genetics and environmental factors.
Researchers have found that anti-CCP positive rheumatoid arthritis patients have a common sequence of amino acids called the shared epitope, which is encoded in specific genetic markers called human leukocyte antigens (HLA). The HLA produces proteins that are responsible for controlling immune responses. It’s thought by some researchers that the shared epitope is what could potentially attach to these proteins and produce the anti-CCP antibodies.
Some researchers feel that there is a strong connection between smoking and rheumatoid arthritis patients who have this shared epitope. It’s thought that the lung inflammation caused by smoking could possibly lead to developing the anti-CCP antibodies in patients who possess this shared epitope.
Anti-CCP is a blood test. A blood sample is drawn from the patient and analyzed in a lab. If the sample finds the presence of anti-CCP at a certain level, the result is positive.
Low levels of anti-CCP can be found in the test results of certain patients but may not enough to produce a positive result. Re-testing later on may be required in patients who continue to display clinical rheumatoid arthritis symptoms.
If a patient tests positive for anti-CCP it doesn’t immediately lead to a rheumatoid arthritis diagnosis. A patient must also exhibit clear clinical symptoms that are consistent with rheumatoid arthritis. These symptoms must also occur for more than six consecutive weeks and meet certain criteria such as how many joints are affected and where.
In some cases, patients who display symptoms of rheumatoid arthritis but who test negative for anti-CCP could still have rheumatoid arthritis or develop it in the future.
In certain cases, positive anti-CCP tests may also indicate the possibility of other conditions besides rheumatoid arthritis. Anti-CCPs have shown to be present in patients with other connective tissue disorders like systemic lupus erythematosus. Despite these rare cases, anti-CCP positivity is highly specific to rheumatoid arthritis.
If a patient is anti-CCP positive and is diagnosed with rheumatoid arthritis, they are said to have seropositive type rheumatoid arthritis. This is as opposed to patients who have been diagnosed with rheumatoid arthritis but test negative for anti-CCPs. These are seronegative type rheumatoid arthritis patients.
In order to reach a rheumatoid arthritis diagnosis when a patient tests positive for anti-CCPs, several other criteria must be met. Doctors will perform a physical examination to look for clear clinical symptoms of rheumatoid arthritis.
Other blood tests are also performed in conjunction with the anti-CCP test, including testing for rheumatoid factor antibodies and increased inflammation levels. Doctors will also use imaging scans to observe any signs of bone and cartilage deterioration around the affected joints.
The anti-CCP test is thought to be slightly more specific than rheumatoid factor is when it comes to reaching a rheumatoid arthritis diagnosis. This is because rheumatoid factor is present in patients without rheumatoid arthritis and who have other autoimmune disorders instead.
If all or most of the criteria are met including testing positive for anti-CCPs, the doctor can make the diagnosis of seropositive rheumatoid arthritis. This is one of two main types of rheumatoid arthritis.
Research has shown that rheumatoid arthritis patients who test positive for anti-CCP could potentially experience a more aggressive set of symptoms. Frequent flare-ups and limited remission periods can be expected in anti-CCP positive rheumatoid arthritis patients. A seropositive result could mean an overall more severe disease course than rheumatoid arthritis patients who don’t test positive for anti-CCP, or are classified as seronegative.
Anti-CCP positive rheumatoid arthritis patients generally receive the optimal and most aggressive treatment options available including taking disease-modifying antirheumatic drugs (DMARDs).
A positive outlook depends on early detection of symptoms followed by a diagnosis. The earlier someone can be diagnosed with anti-CCP positive rheumatoid arthritis the sooner targeted treatment can begin. Early detection can help patients to maintain their quality of life and prevent the severe progression of rheumatoid arthritis symptoms.