C reactive protein

Production and function

CRP is one of many plasma proteins that comprise the “acute phase proteins” and is a sensitive systemic marker of inflammation. It is synthesised by the liver in response to microbial infection, tissue injury, and autoimmune disorders in the acute phase of the response. This phase of the response comprises non-specific physiological and biochemical reactions to most forms of tissue damage, infection, inflammation, and malignant neoplasia. The synthesis of proteins is rapidly upregulated, principally in hepatocytes, under the direct control of cytokines that originate at the site of pathology.2 CRP can also be expressed by smooth muscle cells in coronary arteries after exposure to inflammatory cytokines.3

Human CRP binds to, aggregates, and precipitates several entities, such as plasma lipoproteins, damaged cell membranes, some phospholipids, apoptotic (dying) cells, and capsular components of bacteria, fungi, and other parasites. Doing so seems to stimulate parts of the immune system, such as the classical complement pathway, which helps antibodies clear …