Urinary and Serum Pteridines in Liver Diseases

Abstract

The aim of this mini-review is to show the usefulness of pteridines as clinical markers. We assayed urinary neopterin and xanthopterin levels in liver disease. Total pterins were oxidized by active carbon to yield xanthopterin. Urinary neopterin levels were elevated in patients with chronic active hepatitis and in those with chronic persistent hepatitis but not in patients with alcohol-induced liver disease or in those with non-alcoholic fatty liver. Urinary xanthopterin levels were elevated in chronic active hepatitis and alcohol- induced liver disease, but not in chronic persistent hepatitis and non-alcoholic fatty liver. Urinary neopterin levels were high in infectious diseases involving activated cell-mediated immunity, and increased urinary xanthopterin reflects liver-cell damage. We also compared plasma neopterin values in anti-hepatits C virus antibody (anti-HCV) -positive or - negative donors with elevated alanine aminotransferase (ALT). Plasma neopterin values of anti-HCV-negative donors with elevated ALT were the same as those of healthy groups. These results show that the ALT elevation in anti-HCV-negative donors is attributable mainly to steatosis due to excess body weight and/or alcohol consumption, rather than viral infection. During the course of these studies, we were also able to identify esophageal carcinoma in the very early stage by measuring urinary pteridine levels. Our results indicate that pteridines are clinically useful indicators. In particular, neopterin may be used as a means of screening for unknown viral infection.