Soluble ICAM-1 (sICAM-1) in biliary atresia and its relationship to disease activity

Intercellular adhesion molecule-1 (ICAM-1) is strongly expressed on the bile ducts and hepatic parenchyma of livers with biliary atresia. A soluble, circulating form of this membrane protein has been found to be elevated in a number of inflammatory hepatic disorders. However, its expression in biliary atresia is unknown. The purpose of this study was to assess the presence of soluble ICAM-1 in infants with biliary atresia in relation to disease activity, degree of cholestasis, and standard liver function tests.

A total of nine patients (n = 9) with biliary atresia (seven) and neonatal hyperbilirubinemia (two) were studied (age range 6 weeks-9 years). Control samples were obtained from three healthy infants (2-10 months). Serum was collected from each patient and stored at -80 degrees C until assayed. Levels of sICAM-1 were measured in duplicate utilizing an ELISA method (Bioscource International). Standard liver function tests (conjugated bilirubin, gamma-glutamyl transpeptidase, alkaline phosphatase, alanine aminotransferase) were determined at the same time. Results are expressed as the means +/- SEM with statistical analysis by Mann-Whitney test.

sICAM-1 levels were significantly elevated in all patients with biliary atresia (997 +/- 56 ng/ml) when compared to controls (P < 0.001). No correlation was found between sICAM-1 levels and conjugated bilirubin, gamma-glutamyl transpeptidase, alkaline phosphatase, and alanine aminotransferase levels or with clinical assessment of disease severity.

sICAM-1 is markedly elevated in biliary atresia reflecting the immunopathology of the disease process but does not appear to correlate with markers of liver function. sICAM-1 may be useful in assessing the effects of immunomodulatory therapy.