Acute phase proteins (APPs)

Abstract

Glycoprotein mediators whose production is significantly modified after activation of the inflammatory response or any other kind of tissue damage. That is why they are also referred to as acute-phase (of inflammation) reactants. They are produced mainly by hepatocytes, but also by monocytes, endothelial cells, fibroblasts and other cells. They are divided into positive and negative APPs. The concentration of positive APPs increases in the course of inflammation, whilst the concentration of negative APPs decreases. Albumin is an example for a negative APP. The increase of the major APPs can be greater than a thousand fold, while the concentration of other positive APPs increases only by less than three fold. C-reactive protein (CRP) and serum amyloid A (SAA) are the most strongly reactive positive APPs in humans.