CD 56 staining in liver biopsies does not help in differentiating extrahepatic biliary atresia from other causes of neonatal cholestasis

Hereby we wanted to examine this staining in our center which is a referral children hospital and to prove its efficacy in our problematic cases.By retrospective review of pathology records during 2000 to 2006 in Markaze Tebbi Koodakan (children hospital related to Tehran University of Medical Sciences), we selected 17 cases of EHBA as patients and 12 cases with other diagnoses as controls, both with some degree of bile ductular proliferation in liver biopsies. EHBA cases were all proved by surgery. Four of control cases also underwent surgery but proved to have open ducts by intra-operative cholangiography. Long term follow up and other tests ruled out EHBA in other 8 cases. Hematoxylin-Eosin stains of paraffin blocks were studied again and freshly prepared sections were immunostained for CD56.Bile ducts and proliferating bile ductules were strongly positive for CD56 in 6 of 17 cases of EHBA. In 7 out of 17, positivity were seen in more than two thirds of portal tracts. In controls, one case showed strong positivity and 6 out of twelve showed positivity in more than two thirds of portal tracts. The intensity and distribution of CD56 staining did not differ significantly between two groups.Despite findings of previous studies, we have shown that CD56 staining can not help as an ancillary test in differential diagnosis of neonatal cholestasis and perhaps other markers should be tested in this regard.Extrahepatic biliary atresia is the most common cause of pathologic infant jaundice and one of the most common reasons for liver transplantation in children [1]. It is a condition in which there is total or segmental obliteration of the extrahepatic duct system [2]. Several reports suggest that it results from prenatal injury and post-inflammatory fibrous obliteration of extra hepatic biliary tree [2]. Several infectious agents such as reovirus 3, rotavirus C, rubella and cytomegalovirus are suggested as causative agents [3]. Classically, a 1 to 2 month old child presents