Scavenger cells with Gram-positive bacterial lipoteichoic acid infiltrate around the damaged interlobular bile ducts of primary biliary cirrhosis

Background/Aims: Gram-positive bacterial DNA is frequently detectable in gallbladder bile of primary biliary cirrhosis (PBC) patients. To advance these findings, lipoteichoic acid (LTA) of Gram-positive bacteria with high antigenicity was examined in liver specimens and bile from PBC patients and controls. Methods: LTA was examined by Western blotting in the gallbladder bile from 15 PBC, 11 cholecystolithiasis and six normal subjects, and by immunohistochemistry in liver specimens from 16 PBC, six primary sclerosing cholangitis (PSC), eight chronic viral hepatitis C (CVH-C) and five normal subjects. Results: In the gallbladder bile, there was no significant difference in the positive rate of LTA between PBC and controls. LTA-containing mononuclear cells were frequently detected in the portal tracts, particularly around the bile ducts and in hepatic sinusoids in PBC, while they were infrequent or occasional in control livers. These LTA-containing cells were sinusoidal endothelial cells and Kupffer cells, and portal monocytes, which frequently expressed scavenger receptor class B type 1. Conclusions: LTA derived from bacterial fragments may reach the bile, not only in the diseased state but also under normal conditions. Such LTA may be involved in the development and progression of portal tract lesions, particularly bile duct lesions, in PBC.