Serum ubiquitin levels in patients with alcoholic liver disease

Serum concentrations of free ubiquitin and multiubiquitin chain as determined by immunoassays were compared between 10 healthy subjects, and 11 patients with alcoholic hepatic fibrosis, 10 with alcoholic cirrhosis, and 6 with viral liver cirrhosis. All measurements of multiubiquitin chains were expressed in terms of a standard multiubiquitin chain reference preparation 1. Serum concentrations (mean +/- SD) of free ubiquitin and multiubiquitin chains were significantly higher in patients with alcoholic cirrhosis (63.5 +/- 33.7 ng/ml and 7.5 +/- 4.6 ng/ml) than in the normal subjects (29.6 +/- 6.6 ng/ml, p < 0.05 and 4.1 +/- 1.7 ng/ml, p < 0.05), and those with alcoholic hepatic fibrosis (34.8 +/- 16.3 ng/ml, p < 0.05 and 3.0 +/- 0.7 ng/ml, p < 0.05) and viral liver cirrhosis (28.8 +/- 7.5 ng/ml, p < 0.05 and 4.2 +/- 1.3 ng/ml, p < 0.05). Serum levels of both forms of ubiquitin in six patients with alcoholic cirrhosis showed a tendency to decline after 3 months of abstinence. In a total of 14 patients with alcoholic liver damage, 11 with brain atrophy had significantly higher serum levels of both ubiquitin forms than did three patients without brain atrophy (p < 0.05). No correlation was seen between serum concentrations of either form of ubiquitin and liver function test results in the patients with alcoholic liver damage. However, serum levels of both forms of ubiquitin levels correlated significantly with cumulative alcohol intake (p < 0.05). A significant correlation (p < 0.05) also was observed between serum levels of multiubiquitin chains and mean corpuscular volume, a marker of alcohol consumption. These results suggest that the serum concentrations of ubiquitin, especially multiubiquitin chain is a good marker for the diagnosis of alcoholic cirrhosis.