Interleukin-6 is the major regulator of acute phase protein synthesis in adult human hepatocytes

Abstract

The three monokines interleukin-1β (IL-1β), tumor necrosis factor α (TNFα), and interleukin-6 (IL-6) modulate acute phase plasma protein synthesis in adult human hepatocytes. Only IL-6 stimulates the synthesis of the full spectrum of acute phase proteins as seen in inflammatory states in humans, i.e. synthesis and secretion of C-reactive protein, serum amyloid A, fibrinogen, α 1-antitrypsin, α 1-antichymotrypsin and haptoglobin are increased while albumin, transferrin and fibronectin are decreased. IL-1β as well as TNFα, although having a moderate effect on the positive acute phase proteins and inhibiting the synthesis of fibrinogen, albumin and transferrin, fail to induce serum amyloid A and C-reactive protein. These data suggest that IL-6 plays the key role in the regulation of acute phase protein synthesis in human hepatocytes.