Serum xanthine oxidase in human liver disease

OBJECTIVES: High concentrations of serum xanthine oxidase (XO) have been re ported during human liver disease and hepatocyte injury in experimental set tings. However, it is unclear whether this elevation reflects hepatocyte ne crosis or has a different meaning. METHODS: The serum level of XO in 64 patients with chronic liver disease (1 7 patients with cirrhosis, 30 with chronic hepatitis, and 17 with cholestat ic disorders) and in 12 control subjects was determined by a competitive EL ISA. Conventional serum markers of liver damage were assessed in all patien ts, and grading and staging were scored in the chronic hepatitis group acco rding to Knodell. RESULTS: The XO serum levels were significantly higher in the patients than in the controls. The differences were also significant when controls were compared to patients with chronic hepatitis and cholestatic disorders separ ately, but not when compared to the cirrhosis group. Patients with cholesta tic disorders had XO values higher than those of patients with cirrhosis or chronic hepatitis. XO levels did not correlate with stage and grade in chr onic hepatitis group. We found a weak but significant positive correlation in patients between XO serum level and gamma -glutamyl transpeptidase (r = 0.37). This correlation was stronger when chronic hepatitis (r = 0.42) and, especially cholestatic disorders (r = 0.71), were separately tested, but w as absent in the cirrhosis group. The XO values positively correlated with alkaline phosphatase in patients with cholestatic disorders. A level of ser um XO > 32 mug/ml specifically identified cholestatic disorders in our stud y population. CONCLUSIONS: A marked elevation of serum XO in patients with chronic liver disease seems to reflect the presence of cholestasis. No correlation betwee n XO levels and histological or serum evidence of hepatocyte necrosis was f ound in these patients. (Am J Gastroenterol 2001;96:1194-1199 (C) 2001 by A m. Coll. of Gastroenterology).