GGTLC1 and cholangitis: In a report by Kawakami et al., nivolumab-related cholangitis was characterized by a dominant increase in the biliary tract enzymes alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (r-GTP) relative to the hepatic enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT) [39].