Quantitative proteomic analysis of peripheral blood mononuclear cells in rheumatoid arthritis

In order to identify proteins differentially expressed in rheumatoid arthritis patients and healthy controls, we used isobaric tagging for relative and absolute protein quantification (iTRAQ) to generate quantitative protein profiles from peripheral blood mononuclear cells (PBMCs) from 10 patients with rheumatoid arthritis and 10 healthy donors. Proteins were extracted, concentrated, pooled, labeled with iTRAQ reagents and subjected to multi-dimensional chromatographic fractionation followed by tandem mass spectrometry. A total of 3,208 proteins were identified based on ProteinPilot TM 3.0 software and the International Protein Index (human 3.62) database. Of these, 83 proteins differed at least 2-fold in expression levels between patients and controls. These results indicate that iTRAQ-based technology can serve as a useful aid for identification and quantification of disease-linked proteins from PBMCs. Several proteins, such as serotransferrin, clusterin, annexin A2, and heterogeneous nuclear ribonucleoprotein A2/B1, may be served as biomarker candidates.