Differential hepatic expression of CD56 can discriminate biliary atresia from other neonatal cholestatic disorders.

ABSTRACT

OBJECTIVES: The diagnosis of biliary atresia (BA) can be challenging as its histopathologic features overlap with those of other pediatric cholestatic liver diseases. We aimed to study the diagnostic value of hepatic CD56 immunostaining in the differentiation of BA from other causes of neonatal cholestasis. METHODS: Hepatic CD56 immunostaining was investigated in 30 infants with BA and compared with that in 30 infants with non-BA cholestatic disorders. The expression of positive cells was interpreted semiquantitatively on the basis of the extent (percentage or number) of positive cells on a scale of 0-3. RESULTS: The occurrence of CD56-positive biliary epithelial cells was significantly higher in the BA (83.3%) than in the non-BA group (6.7%), whereas the occurrence of CD56 natural killer cells in hepatic parenchyma was significantly higher in the non-BA group (76.7%) than in the BA group (6.7%; P<0.0001 for both). In contrast, there was no significant difference between both groups in CD56 natural killer cells in portal tracts (P>0.05). Using this differential expression as a discriminative tool between the BA and the non-BA group, positive biliary epithelial cell staining had high specificity, whereas negative parenchymal staining had high sensitivity (93.3% for both) with an accuracy of 88.3 and 84.65%, respectively. The combination of both parameters improved the accuracy up to 91.65%, with 100% specificity in the diagnosis of BA. CONCLUSION: CD56 immunostaining of the liver had a diagnostic value; it can be used to differentiate BA from other neonatal cholestatic disorders and might be useful as an additional stain when investigating infants with neonatal cholestasis.