Application of leucine aminopeptidase in biliary obstructive diseases

Objective To investigate the role of leucine aminopeptidase in biliary obstructive disease, and to evaluate the value of leucine aminopeptidase and its combination with alkaline phosphatase (AKP), glutamine transferase and 5′-nucleotidase (5′-NT) in diagnosis and treatment of bile duct obstruction. Methods A total of 181 cases were collected, who were diagnosed as healthy, asymptomatic HBV carriers and patients with hepatitis, biliary obstruction, liver cirrhosis and primary liver cancer samples at Xiangya Hospital of Central South University from October 2016 to March 2017. The leucine aminopeptidase (LAP), AKP, gamma glutamyl transpeptidase (GGT) and 5′-NT were detected with the corresponding kits, and analyzed with different statistical methods. Results The highest level of LAP was in patients with biliary obstruction, compared to other groups, and the differences were statistically significant (P<0.05). In biliary obstruction group, LAP and AKP, GGT and 5′-NT were correlated (r=0.690, P<0.01; r=0.864, P<0.01; r=0.735, P<0.01). Receiver operating characteristic (ROC), curve area (AUC) of LAP, 5′-NT, GGT and AKP in the diagnosis of biliary obstruction were 0.945 and 0.898, 0.942 and 0.916; the AUC of LAP combined with 5′-NT, GGT and AKP was 0.966; and the AUC of LAP combined with 5′-NT was 0.968. Conclusions LAP can be used as a preliminary index of differential diagnosis of biliary obstructive disease, and its diagnostic value could be improved when combined with 5-NT. Key words: Leucyl aminopeptidase/DU; Cholestasis/DI; Biliary tract diseases/DI