Review: Biology and relevance of C-reactive protein in cardiovascular and renal disease

C-reactive protein (CRP) is a member of the pentraxin family of proteins, which are characterised by a cyclic pentameric structure and radial symmetry. The five identical 24-kDa protomers consist of 206 amino acids, and are noncovalently linked. CRP binds to a range of substances such as phosphocholine, fibronectin, chromatin, histones, and ribonucleoprotein in a calcium-dependent manner. It is a ligand for specific receptors on phagocytic leukocytes, mediates activation reactions on monocytes and macrophages, and activates complement. Plasma CRP is the classical acute-phase protein, increasing 1,000-fold in response to infection, ischemia, trauma, burns, and inflammatory conditions. A growing number of studies suggest that CRP is an independent risk factor for atherosclerotic vascular disease. Plasma CRP concentrations in the highest quartile are associated, depending on the subject group, with 1.5- to 7-fold increases in relative risk. In the high-risk endstage renal failure population, a raised CRP is associated with up to 5.5-fold increased relative risk of CVD and 4.6-fold increased relative risk of death. This review examines the relationships between CRP, cardiovascular disease, and mortality, with special reference to renal disease.