Frequent infiltration of S-100 protein+ CCR5+ immature dendritic cells in damaged bile ducts of primary biliary cirrhosis compared to cholangiocellular carcinoma

Hiroko Mitsui,1,2 Hiroya Ohtake,1 Rintaro Ohe,1 Mitsunori Yamakawa1 1Department of Pathological Diagnostics, 2Department of Gastroenterology, Yamagata University Faculty of Medicine, Yamagata, Japan Abstract: Dendritic cells (DCs) are professional antigen presenting cells that initiate immune responses. We evaluated the relationship between DC infiltration, chemokines/chemokine receptors, and bile duct damage in primary biliary cirrhosis (PBC), compared to cases of cholangiocellular carcinoma arising from the bile duct. Immunohistochemistry revealed significantly more S-100 protein+ DCs infiltrating the epithelial layer of bile ducts in PBC than in chronic hepatitis C or control neonatal livers. Furthermore, a higher number of S-100 protein+ DCs, but not fascin+ or DC lysosomal associated membrane protein+ mature DCs, were found in the epithelial layer of the damaged bile ducts of the PBC liver. CC-chemokine receptor (CCR) 5+ immature DCs frequently accumulated in the portal area in PBC. CCR5 mRNA was also detected in liver tissues from PBC patients by reverse transcription polymerase chain reaction. In situ hybridization revealed the expression of macrophage inflammatory protein (MIP)-1α and MIP-1 mRNA in the epithelial cells of damaged bile ducts. However, no CD1a+ immature DCs were found in any of the PBC or chronic hepatitis C specimens or in neonatal liver, whereas they occurred frequently in the cancer nests of cholangiocellular carcinoma, which expressed MIP-3α and were frequently infiltrated by CCR6+ DCs. These results indicate that bile ducts damaged by PBC secrete MIP-1α and MIP-1 , while neoplastic ones secrete MIP-3α. They also suggest that CCR5+ immature DCs attracted by MIP-1α and MIP-1 may play an important role in the pathogenesis of chronic nonsuppurative destructive cholangitis in PBC. Keywords: chemokines, cholangiocellular carcinoma, chronic nonsuppurative destructive cholangitis, dendritic cell, primary biliary cirrhosis