Involvement of IL-18 and soluble fas in patients with postoperative hepatic failure

We measured the levels of tumor necrosis factor alpha (TNF-alpha), interleukins (IL)-6 and -18, and soluble Fas (sFas) in 11 patients with postoperative hepatic failure and assessed whether IL-18-mediated apoptosis is involved in the onset of liver dysfunction. The serum TNF-alpha, IL-18, and sFas levels were significantly higher in patients with sepsis as a complication than in those without sepsis. The TNF-alpha and IL-18 levels were significantly higher in nonsurvivors than in survivors. Significant correlations were observed between TNF-alpha and IL-6, between TNF-alpha and IL-18, and between TNF-alpha and sFas levels. These results showed that Fas-mediated hepatocyte apoptosis functions as an important mechanism responsible for the onset of postoperative hepatic failure in humans. They especially suggested that IL-18 and TNF-alpha function both as apoptosis-promoting factors and as apoptosis-inhibiting factors, depending on the conditions to which hepatocytes are subjected.