Serum proteomic MRM identify peptide ions of transferrin as new fibrosis markers in chronic hepatitis B.

ABSTRACT

BACKGROUND AND AIM: Because of the limitations of liver biopsy, reliable non-invasive serum biomarkers of liver fibrosis are needed. The aim of this study was to identify such markers by the use of serum proteomics in chronic hepatitis B (CHB). METHODS: Two-dimensional gel electrophoresis (2-DE) was used to identify differentially expressed protein spots in sera from 40 CHB patients [20 with mild fibrosis (S0-S1) and 20 with severe fibrosis (S3-S4)]. Mass spectrometry (MS) based multiple reaction monitoring (MRM) was used to quantify peptide ions of differential protein spots in another set of sera from 86 CHB patients with different liver fibrosis (S0-S4). RESULTS: Seven differentially expressed protein spots were found by 2-DE. Fourteen peptide ions of seven target protein spots were quantified by MS-based MRM. Summed peak areas ratio (SPAR) values of peptide ions from protein spot 1, 4 and 8, identified as apo serum transferrin, complement component C3c and transferrin, were significantly different from non-fibrosis (S0) to fibrosis stage 4. AUROCs of models established by peptide ions (protein spot 1, 4, 8) and model consisting of a combination of all ions were 0.848∼0.966 (S2-S4 versus S0-S1) and 0.785∼0.875 (S3-S4 versus S0-S2). Only the peptide ions model of transferrin had better sensitivity and specificity for predicting fibrosis stages than did aspartate aminotransferase-to-platelet ratio index (APRI), FIB-4 and Forn's index. CONCLUSIONS: Serum peptide ions of transferrin, detected by proteomic MRM, are new and promising biomarkers for staging liver fibrosis in CHB patients.