The biliary tree: A new frontier in mucosal immunology?

Area of Science:

• Immunology
• Gastroenterology
• Hepatology

Background:

• Mucosal immunology studies surfaces exposed to microbes and antigens.
• The biliary tree, though a mucosal surface, is not traditionally recognized as a mucosal immune epithelium.
• Emerging research highlights the biliary tree's crucial roles in liver immunology and bile homeostasis, impacting liver disease progression.

Purpose of the Study:

• To investigate whether bile ducts should be classified as part of the mucosal immunology system.
• To review the immune functions and plasticity of biliary epithelial cells.

Main Methods:

• Literature review of emerging studies on biliary tree immunology.
• Analysis of biliary epithelial cell sensing capabilities, proteome, and secretome.

Main Results:

• Biliary epithelial cells possess sensing capabilities and plasticity akin to mucosal immune epithelia.
• The biliary tree plays intricate roles in liver immunology and bile homeostasis.
• Dysfunction in the biliary tree has consequences for liver disease initiation and progression.

Conclusions:

• Bile ducts exhibit characteristics and functions that warrant their consideration within the mucosal immunology system.
• Further research is needed to fully elucidate the immune functions of the biliary tree.