Characterization of plasma proteome in biliary atresia

Background: Biliary atresia (BA) is a disorder during infancy with unknown etiology in which progression frequently leads to liver cirrhosis. Plasma proteome is characterized in this study. Methods: Twelve paired plasma samples from 6 children with BA who received surgical correction at early stage and then liver transplantation at late stage of liver cirrhosis were studied. Plasma samples from 2 subjects without liver disorder were used as normal reference for 2-dimensional gel electrophoresis and for identification of protein spots by mass spectrometric analysis. Plasma samples from another 3 normal subjects (with a total of 5) were used for nephelometric quantification of immunoglobulin kappa light chain in comparison with patients' samples. Results: Among the protein spots detected, ranging from 6 to 200 kDa mass with pIs of 3-10, significant up-regulation of immunoglobulin kappa light chain was found at the late stage of BA, which was subsequently confirmed by nephelometric analysis. Conversely, significant decrease of apolipoprotein (Apo) A-I and C-II, haptoglobin α2 and β chain, and transthyretin were detected during the progression of BA. Conclusions: Increased immunoglobulin kappa light chain detected in late-stage BA characterizes adverse immune modulation in this disorder. Decreased apolipoproteins, haptoglobin and transthyretin levels might be potential markers of progressive liver injury, fibrosis and defective lipid metabolism in BA.