Secretory immunoglobulin deposits in renal glomeruli of children with extrahepatic biliary atresia: studies in a human counterpart of experimental ligation of the bile ducts

Abstract

Experimental ligation of the biliary tract often results in glomerular deposits of polymeric IgA commonly associated with secretory component. These studies offer evidence that, in animals, hepatobiliary transport of polymeric IgA, which is of mucosal origin, is crucial for its clearance from the serum. We studied a human counterpart of bile duct ligation--extrahepatic biliary atresia--for the presence of secretory or polymeric immunoglobulins in renal glomeruli. Kidney was available at autopsy as paraffin or frozen blocks from 24 patients with biliary atresia and age-matched controls (5 weeks to 5 years old). Several of the patients had undergone portoenterostomy (Kasai procedure) or liver transplantation. Immunohistologic studies showed glomerular (often mesangial) deposits of IgA in 10 of 24 and IgM in 16 of 24 specimens. The differences with controls were highly significant for IgA but not for IgM. In frozen sections, secretory component was positive in glomeruli in seven of 12 specimens. In vitro glomerular binding of purified secretory component to glomeruli was shown in four of 12 samples, including three with IgM only. This last observation suggests that IgM in some of these patients was polymeric and thus derived from a mucosal source. Our study shows that in humans with biliary atresia, secretory IgA, polymeric IgA, and possibly polymeric IgM are deposited in glomeruli. The study confirms the occurrence of renal immunopathologic findings in liver disease and supports the existence of an active hepatobiliary immunosecretory transport mechanism even at the early age of these patients.