Late persistence of serum gamma-glutamyl transpeptidase activity after mononucleosis. Report of 3 cases.

gamma-Glutamyl transpeptidase (GGTP) is a sensitive but nonspecific index hepatobiliary disease. In infectious mononucleosis (IM) or the mononucleosis-like disease attributable to cytomegalovirus (cytomegalovirus-induced IM), GGTP reverted to normal later than aspartate aminotransferase and alkaline phosphatase. In three cases elevated serum GGTP activity persisted for up to 24 months -- raising the question of persistent 'post-IM' hepatitis. Such prolonged GGTP activity was unusual in other late IM specimens. Possible, but unlikely, causes for such persistent GGTP activity are an unusual degree of hepatic damage during acute IM, excessive induction of microsomal enzyme system activity by drugs, or unusual Epstein-Barr virus carrier state activation that might contribute to ongoing hepatic structural damage. Other markers of chronic hepatocellular disease including aspartate aminotrasferase, alkaline phosphatase, and bilirubin were normal in late specimens from these 3 patients. The cause of their persistent elevated GGTP activities remains unknown.