OBJECTIVETo identify plasma biomarkers with specific relation to the various liver fibrosis stages that can be used to assess hepatitis B virus (HBV)-infected patients for non-invasive liver fibrosis and to evaluate the prognosis of the liver fibrosis.

METHODSPlasma samples were collected from 80 HBV-positive patients at the Hepatitis Department of Shanghai Public Health Clinical Center between September 2008 and January 2011. The samples were grouped according to the patient's stage of hepatic fibrosis determined by liver biopsy: S0-1 (n = 40), S2-3 (n = 20), and S4 (n = 20). Each plasma sample was processed to remove the two most abundant proteins, albumin and immunoglobulin G (IgG), and then resolved by two-dimensional (2D) electrophoresis. ImageMaster 2D analysis software was used to identify differentially expressed proteins related to the liver fibrosis stages. After trypsin digestion, the differential proteins were identified by online reversed-phase nano-flow liquid chromatography coupled with electrospray ionization ion trap mass spectrometry (MS).

RESULTSThe patients in the three groups were not significantly different in age (range: 30-50 years; P = 0.053) or sex (x² = 0.155, P = 0.926). Low-abundance proteins were efficiently enriched by the albumin/IgG depletion method. Fourteen differentially expressed proteins were detected among the S0-1, S2-3 and S4 groups, all of which were identified by tandem MS and included fibrinogen gamma chain, haptoglobin, complement C3, Ig kappa chain C region, and apolipoprotein A-I.

CONCLUSIONPlasma proteomic analysis of chronic hepatitis B patients identified a panel of differentially expressed proteins related to different stages of liver fibrosis. These proteins may represent diagnostic and prognostic biomarkers of HBV-related hepatic fibrosis.