Acute-phase proteins are a class of proteins that are synthetized in the liver in response to inflammation. This response is called the acute-phase reaction. In response to injury, local inflammatory cells (neutrophil granulocytes and macrophages) secrete a number of cytokines into the bloodstream, most notable of which are the interleukins IL-1, IL-6 and IL-8, and TNF-alpha.

The liver responds by producing a large number of acute-phase reactants, most notable of which are:

• C-reactive protein
• Mannose-binding protein
• Alpha 1-antitrypsin
• Alpha 1-antichymotrypsin
• Alpha 2-macroglobulin
• some coagulation factors (Fibrinogen, prothrombin, factor VIII, von Willebrand factor, plasminogen)
• Complement factors
• Ferritin
• Serum amyloid P component (see amyloid)

Serum albumin concentrations fall in acute disease states. For this reason albumin is sometimes referred to as a negative acute phase protein.

Measurement of acute phase proteins is a useful marker of inflammation in both medical and veterinary clinical pathology.

Acute phase proteins | Immune system

Protéine de phase aiguë