[Studies on the mechanism of elevation of serum PIVKA-II levels in alcoholic liver cirrhosis].

We measured serum PIVKA-II concentrations in 18 patients with alcoholic liver cirrhosis. Alcoholic liver disease was diagnosed by the history of ethanol intake of more than 900 ml/day for over 10 years. Liver cirrhosis was diagnosed histologically. Infections with hepatitis B and C viruses were ruled out by assaying serum virus markers. No tumor was detected in liver by ultrasonography and computed tomography during observation period. None of the patients studied were positive for alpafetoprotein (AFP). Eight out of 18 (44.4%) patients with alcoholic liver cirrhosis showed elevated serum PIVKA-II levels. In contrast, only eight out of 93 (8.6%) patients with nonalcholic liver cirrhosis had elevated serum PIVKA-II levels. PIVKA-II is well known as a tumor marker of hepatocellular carcinoma (HCC). The rates of positive PIVKA-II found in alcoholic liver cirrhosis approached its rates in HCC. However, the time course for the elevation of serum PIVKA-II levels was different each other in alcoholic liver cirrhosis and HCC. In HCC, serum PIVKA-II "levels" continued to elevate until therapy. In contrast, its elevation was transient and its levels returned to baseline in alcoholic liver cirrhosis. The values of ALT (GPT), gamma-GTP, and ALP correlated poorly with serum PIVKA-II levels in patients with alcoholic liver cirrhosis. To investigate the mechanism by which elevation of serum PIVKA-II levels in patients with alcoholic liver cirrhosis occurred, we studied the effect of vitamin K on production of PIVKA-II and AFP by hepatocytes. Hepatocytes(Alexander PLC/PRF/F cell line) were cultured in the presence of various concentrations of vitamin K (Kaytwo, Eisai, Tokyo). Vitamin K had no effect on AFP production. In contrast, PIVKA-II production was inhibited by addition of vitamin K in a dose dependent manner. Moreover, elevation of serum PIVKA-II levels in patients with alcoholic liver cirrhosis was suppressed by administration of vitamin K (Kaytwo) to these patients. Taken together, these results suggest that vitamin K may have a role in the mechanism of PIVKA-II elevation in sera of these patients. Then, we measured serum concentrations of vitamin K(PK, MK-4, MK-7) in these patients. There was no correlation observed between vitamin K and PIVKA-II in these patients. This result suggests that elevation of serum PIVKA-II in these patients may not be due to vitamin K deficiency. One question not answered here is how serum PIVKA-II levels in these patients are suppressed by treatment with vitamin K (Kaytwo). More detailed analysis of the mechanism of elevation of serum PIVKA-II levels in patients with alcoholic liver cirrhosis is needed.