Complement in local biliary tract defense: dissociation between bile complement and acute phase reactants in...

Area of Science:

• Gastroenterology and Immunology
• Biliary Tract Pathophysiology

Background:

• Biliary complement concentrations are lower in infected bile compared to sterile bile.
• Plasma complement increases during systemic inflammation (acute phase response).
• The role of biliary complement in cholecystitis requires clarification.

Purpose of the Study:

• To investigate if low biliary complement in infected bile reflects a specific biliary tract infection response or a general systemic reaction.
• To analyze biliary complement proteins (C3, C4) and activity (C4H50) alongside acute phase reactants in cholecystitis.

Main Methods:

• Analysis of bile complement (C3, C4, C4H50) and acute phase reactants (fibronectin, C-reactive protein, alpha 1-antitrypsin) in acute and chronic cholecystitis.
• Correlation of biliary analytes with bile cultures and gallbladder histology.
• Statistical analysis using the Wilcoxon rank sum test.

Main Results:

• Biliary C3, C4, and C4H50 were significantly lower in infected bile versus sterile bile.
• No significant difference in acute phase reactants between infected and sterile bile.
• Biliary acute phase reactants were higher in acute cholecystitis than chronic, but biliary complement levels did not differ between these groups.
• No clear correlation between plasma complement levels and acute phase reactants.

Conclusions:

• Biliary complement levels are specifically reduced in infected bile, indicating a localized response.
• The dissociation between biliary complement and systemic acute phase reactants suggests bile complement is not merely a marker of systemic inflammation.
• Biliary complement is proposed as a specific host defense mechanism against bacterial infections within the biliary tract.