C-reactive protein: Encyclopedia - C-reactive protein

C-reactive protein

C-reactive protein (CRP) is a plasma protein, an acute phase protein produced by the liver. It is a member of the pentraxin family of proteins.

C-reactive protein - History and nomenclature

CRP was originally discovered by Tillett and Francis in 1930 as a substance in the serum of patients with acute inflammation that reacted with the C polysaccharide of pneumococcus.

C-reactive protein - Genetics

The CRP gene is located on the first chromosome (1q21-q23).

C-reactive protein - Function

CRP is a member of the class of acute phase reactants as its levels rise dramatically during inflammatory processes occurring in the body. It is thought to assist in complement binding to foreign and damaged cells and affect the humoral response to disease.

C-reactive protein - Diagnostic use

CRP is used mainly as a marker of inflammation. Measuring and charting C-reactive protein values can prove useful in determining disease progress or the effectiveness of treatments. Blood, usually collected in a serum-separating tube, is analysed in a medical laboratory or at the point of testing.

Various analytical methods are available for CRP determination, such as ELISA, immunoturbidometry, rapid immunodiffusion and visual agglutination.

Viral infections tend to give a lower CRP level than bacterial infection.

C-reactive protein - Role in cardiovascular disease

Recent research suggests that patients with elevated basal levels of CRP are at an increased risk for hypertension and cardiovascular disease, although recent research[1] suggests the correlation is moderate.

The amount of CRP produced by the body varies from person to person, and this is affected by lifestyle as well as genetic makeup, which accounts for almost half of the variation in CRP levels between different people. Higher CRP levels tend to be found in smokers and in people who are sedentary, overweight or who have high blood pressure. Lean, athletic individuals tend to have lower CRP levels.

Research shows that too much inflammation can sometimes have adverse effects on the blood vessels which transport oxygen and nutrients throughout our bodies. Atherosclerosis, which involves the formation of fatty deposits or plaques in the inner walls of the arteries, is now considered in many ways an inflammatory disorder of the blood vessels, similar to how arthritis is an inflammatory disorder of the bones and joints. Inflammation not only affects the atherosclerotic phase of heart disease, but also the rupturing of plaques which can then travel and interfere with blood flow, causing a heart attack.

Many studies have shown an association between elevated levels of inflammatory markers (including CRP) and the future development of heart disease. This is true even for apparently healthy men and women who have normal cholesterol levels. The reason CRP can be used by physicians as part of the assessment of a patient's risk for heart disease is because it is a stable molecule and can be easily measured with a simple blood test. In patients already suffering from heart disease, doctors can use CRP levels to determine which patients are at high risk for recurring coronary events.

To measure the CRP level, a "high-sensitivity" CRP or hs-CRP test needs to be performed and analyzed by a laboratory. This is an automated blood test designed for greater accuracy in measuring low levels of CRP, which allows the physician to assess cardiovascular risk. If a result in the low-risk range is found ( < 1 mg/L), it does not need repeating. Higher levels need repeating, and clinical evaluation as necesary.

C-reactive protein - Role in colon cancer

The role of inflammation in cancer is not well known. Some organs of the body show greater risk of cancer when they are chronically inflamed.

Blood samples of persons with colon cancer have an average CRP concentration of 2.69 milligrams per liter. Persons without colon cancer average 1.97 milligrams per liter. The difference was statistically significant(Erlinger et al 2004). These findings concur with previous studies that indicate that anti-inflammatory drugs could lower colon cancer risk (Baron et al 2003).

See also

• acute phase
• erythrocyte sedimentation rate
• immunology

Adapted from the Wikipedia article "C-reactive protein", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki