[Proteins of the inflammatory reaction. Regulatory functions]

There is a very important modification of the plasma protein equilibrium during an inflammatory reaction. Most of the proteins, except the immunoglobulins, have their biosynthesis or catabolic rate modified. The plasma concentration of these proteins may be increased, decreased or equal to the normal values. Clinically, the term "Acute Phase Protein" APP is reserved for the proteins whose plasma concentration is at least 50 per cent higher than normal values. These APP are: alpha-1 acid-glycoprotein, alpha-1 proteinase inhibitor, alpha-1 antichymotrypsin, haptoglobin, ceruloplasmin, fibrinogen, C-reactive protein, serum amyloid A protein. Interleukin-1 induces the APP's hepatic biosynthesis. The APP and, more generally, a lot of plasma proteins play a role during inflammatory reaction. They have some real functions of metabolic regulators. The functions result from the interaction of these proteins with ligands of various origins which give "protein-ligands" complexes. These complexes are cleared by the RES or by the hepatocyte. The results are protease inhibition, neutralization of toxic molecules such as hemoglobin or the superoxide anion, clearance of cell membranes and chromatin. The interaction of plasma proteins and particularly the APP's with different ligands issued from the inflammatory site, is an example of physiopathological self regulation.