Increased serum and hepatic tissue levels of interleukin-18 in patients with fulminant hepatic failure

Background: Fulminant hepatic failure is a serious clinical condition associated with a high mortality rate. Interleukin (IL)-18 is a pro-inflammatory cytokine that is associated with several inflammatory diseases. The purpose of the present paper was therefore to investigate whether IL-18 is elevated in patients with fulminant hepatic failure. Methods: Serum levels of IL-18 were measured in patients with fulminant hepatic failure before and after liver transplantation. Native liver tissue samples were collected and the tissue levels of IL-18 were determined. Liver tissues were stained immunohistochemically with antihuman IL-18 antibody. The serum levels of IL-1β, IL-6, IL-8, IL-12, interferon-γ, and tumor necrosis factor-α were also determined in patients with fulminant hepatic failure before and after liver transplantation. Results: Elevated levels of IL-18 in serum and hepatic tissue were observed in patients with fulminant hepatic failure. Native liver tissue samples were immunohistochemicaly positive for IL-18. Interleukin-18 levels were markedly reduced after liver replacement. No other inflammatory cytokines were substantially elevated in patients with fulminant hepatic failure. Conclusion: The serum levels of IL-18 levels are elevated much more than those of other cytokines in patients with fulminant hepatic failure.