Bile immunoglobulins and blockage of biliary endoprosthesis: an immunohistochemical study

BACKGROUND: Endoscopic biliary stenting for pancreaticobiliary malignancy is often limited by recurrent stent occlusion as a result of bacterial biofilm formation and sludge deposition. Bile immunoglobulins are thought to be important in combating biliary sepsis. OBJECTIVES: To investigate whether bile immunoglobulins are involved in the pathogenesis of stent blockage. DESIGN: Immunohistochemical technique was used to study the distribution of bile immunoglobulins, bacteria and sludge in blocked biliary stents. METHODS: Patients with malignant obstructive jaundice were palliated by endoscopic insertion of a 10-FG polyethylene stent into the biliary tract. Blocked stents were retrieved from those who presented with recurrent jaundice and fever. The stents were cross-sectionally cut into slices and fixed in formalin. Immunoglobulins were demonstrated by the peroxidase-anti-peroxidase staining procedure using rabbit anti-serum. RESULTS: The central bulk of the stent deposits appeared as an amorphous, structureless material. IgA was found as a rim of dark brown discoloration at the periphery. IgG showed similar distribution and intensity to that of IgA whereas little IgM was detected. CONCLUSIONS: Bile immunoglobulins may facilitate bacterial adhesion, clumping, and hence biofilm formation on the stent surface.