Comparative proteome analysis of peripheral blood mononuclear cells in systemic lupus erythematosus with iTRAQ quantitative proteomics.

To identify and quantify protein profiles from peripheral blood mononuclear cells (PBMC) of systemic lupus erythematosus (SLE) patients with isobaric Tagging for Relative and Absolute protein Quantification (iTRAQ)-based proteomic technology and to find differentially expressed proteins in SLE. PBMC were collected from patients of six stable SLE, six active SLE, six rheumatoid arthritis (RA), and six healthy donors. After protein extraction and concentration, the pooled protein content was labeled with iTRAQ reagents and then subjected to multiple chromatographic fractionation and tandem mass spectrometry. ProteinPilot™ 3.0 software and a database of IPI (International Protein Index) human 3.62 were used for database searching and statistical analysis. A total of 452 proteins were identified. Of these, 67 unique proteins were observed twofold or more alteration in levels across groups. The proteins determined support existing knowledge and uncover novel biomarker candidates. These results indicate that iTRAQ-based technology can serve as a useful aid for identification and quantification proteins from PBMC.