Table 1. Serum protein synthesis by the liver during the acute phase response.

Proteins induced in APR	Examples	Immune function
Complement proteins	C3, C4 and C9	Enhance phagocytosis, act as chemoattractants, induce cell degranulation, enhance vascular permeability and induce bacterial cell lysis
Iron-binding proteins	Haptoglobin, hemopexin, ferritin and hepcidin	Act to reduce free iron in the serum and antimicrobial functions
Antimicrobial proteins	Liver expressed antimicrobial peptide 2, hepcidin	Antimicrobial activity
Clotting factors	Fibrinogen, prothrombin, factor VIII, factor IX and Von Willebrand factor	Enhance coagulation
Inflammatory proteins	IL-6, lipopolysaccahride-binding protein and secreted phospholipase A2	Enhance pro-inflammatory signals and potentiate the APR
Lectins, pentraxins, ficolins and collectins	C-reactive protein, mannose-binding lectin, collectin liver 1, ficolin-2 and serum amyloid P	Active complement and enhance phagocytosis
Protease inhibitors	α2-Macroglobulin, α1-antichymotrypsin and α1-antitrypsin	Anti-inflammatory functions via the inhibition of coagulation, neutrophils and mast cells

Abbreviation: ARP, acute phase response.