C-reactive protein is a pro-inflammatory molecule produced by the liver and is normally found in the blood only during acute infection or injury. In a healthy immune response, levels of c-reactive protein rise rapidly, the molecule binds to injured tissue and activates the immune response and then levels recede quickly, as the other components of the immune system take over the healing process. In conditions of chronic inflammation, c-reactive protein remains elevated and serves as an indicator of potential inflammatory disease conditions.
General Inflammation Indicator
C-reactive protein is used as a test for generalized inflammation, as opposed to an indication for inflammation occurring in a particular part of the body, according to the University of Maryland Medical Center. It is also useful as a gauge to measure flareups of existing conditions, such as rheumatoid arthritis or lupus, and to see how well anti-inflammatory medications are working. Because c-reactive protein is a general indicator, it may not show up inflammation in all cases for reasons not fully understood, and some people with recognized inflammatory conditions may show normal levels of c-reactive protein.
Heart Health
A type of c-reactive protein test known as heart specific c-reactive protein has been developed that is highly sensitive for inflammation in the cardiovascular system, according to Harvard Health Publications. This test, combined with your cholesterol levels and other factors, help your doctor to determine your overall risk for heart problems. Only 50 percent of people who experience heart attacks have elevated LDL cholesterol, an indicator that cholesterol testing is not an adequate screening tool by itself. Inflammation, as determined by the heart specific c-reactive protein test, has been implicated as an initiating factor in arterial plaque formation. The current c-reactive protein test is highly sensitive and inexpensive, and the "New England Journal of Medicine" endorsed it in its November 2002 issue as being superior to cholesterol in predicting cardiovascular risk.
Atherosclerosis Indicator
A study published in the March 2010 "Canadian Journal of Cardiology" found that high levels of c-reactive protein do not directly cause atherosclerosis, but rather are an indicator of inflammation in the blood vessels that can point out the presence of atherosclerosis. The most protective combination of factors seems to be low levels of heart specific c-reactive protein combined with normal levels of LDL cholesterol. Statin therapy was used in a study of healthy adults with elevated heart specific c-reactive protein and normal LDL cholesterol and found to reduce overall risk by 44 percent, the "Canadian Journal of Cardiology" also reported.
Genetics
Your genetic makeup determines your baseline c-reactive protein levels, according to a study published in the April 2011 issue of the "National Review of Rheumatology." C-reactive protein serves a role in the immune system by helping to clear bacteria and dead cells out of the body and may modulate other aspects of the immune response that pertain to autoimmune conditions, including lupus and rheumatoid arthritis. The researchers found that some people have genetic variations that predispose them to higher or lower levels of c-reactive protein and this also determines the degree of inflammation that occurs in response to an inflammatory trigger or a flareup of an autoimmune disease. The researchers recommend that genetic factors be considered when categorizing a person's disease activity level based on c-reactive protein levels.
References
- University of Maryland Medical Center: C-Reactive Protein - Overview
- " Harvard Health Publications"; C-Reactive Protein Test to Screen for Heart Disease; Why Do We Need Another Test?; February 2003
- "The Canadian Journal of Cardiology"; C-Reactive Protein: Risk Factor, Biomarker And/or Therapeutic Target?; Genest J.; March 2010
- "National Reviews: Rheumatology"; C-Reactive Protein in Rheumatology: Biology and Genetics. Rhodes B, et al.; April 2011
- TheFreeMedicalDictionary.com: C-Reactive Protein
- "Annals of Medicine"; Function of C-Reactive Protein. Du Clos TW.; May 2000
