Immunohistochemical characterization of the regenerative compartment in biliary atresia: a comparison between Kasai procedure and transplant cases

SummaryBiliary atresia (BA) accounts for most cases of pathologic infantile jaundice, which may lead to cirrhosis and eventually necessitate liver transplantation (LT). A cardinal histologic feature of BA is ductular reaction (DR), reflecting activation of the regenerative compartment in liver. We examined the immunohistochemical attributes of the progenitor cell population and its immediate descendants in BA patients undergoing Kasai procedure (KP) or LT. The BA cases were divided into those undergoing KP (n = 24) and those undergoing LT (n = 64). Immunohistochemistry for CD56, CK7, and CK19 was performed. Patients with BA (both KP and LT groups) had more DR than controls (scores 2.4, 2.2, and 0.1, respectively; P < .001), but the degree of DR did not differ between BA patients undergoing KP compared to LT. There was significantly more CD56 staining in DR in LT (2.5) versus KP samples (1.3; P < .001), with a trend toward the same pattern in hepatocyte progenitor cells in these samples (0.6 versus 0.2; P = .05). In intermediate hepatocytes, CK7 staining was higher in LT versus KP samples (1.7 versus 0.3; P < .001). No differences in CK19 staining were noted in the cell types in different BA groups. Immunohistochemistry suggests that the regenerative compartment is expanded in patients undergoing LT for BA, compared to patients with an earlier stage of disease undergoing KP. These observations support the notion that there is more active regeneration in livers with advanced-stage BA and highlight the immunophenotypic heterogeneity of progenitor cells in different phases of the disease.