RT Journal Article SR Electronic T1 Identify Biomarkers of Neuropsychiatric Systemic Lupus Erythematosus by Matrix-assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Combined with Weak Cation Magnetic Beads JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 454 OP 461 DO 10.3899/jrheum.100550 VO 38 IS 3 A1 LING SUN A1 HUA CHEN A1 CHAOJUN HU A1 PENG WANG A1 YONGZHE LI A1 JING XIE A1 FULIN TANG A1 DENIAN BA A1 XUAN ZHANG A1 WEI HE YR 2011 UL http://www.jrheum.org/content/38/3/454.abstract AB Objective. To identify proteomic biomarkers in cerebrospinal fluid (CSF) and develop a diagnostic proteomic model for neuropsychiatric systemic lupus erythematosus (NPSLE). Methods. CSF proteomic spectra were generated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) combined with weak cation exchange (WCX) magnetic beads. The spectra were taken from 27 patients with NPSLE before and after treatment, and 27 controls including 17 patients with scoliosis and 10 patients with SLE but without neuropsychiatric manifestation. Discriminating peaks were processed by Biomarker Patterns Software to build a decision tree model for NPSLE classification. In addition, CSF samples of 12 patients with NPSLE, 12 patients with lumbar disc herniation, and 9 patients with other neurological conditions were used as a blind test group to verify the accuracy of the model. Results. Twelve discriminating mass-to-charge (m/z) peaks were identified between NPSLE and controls: m/z peaks 7740, 11962, 8065, 7661, 6637, 5978, 11384, 11744, 8595, 10848, 7170, and 5806. The diagnostic decision tree model, built with a panel of m/z peaks 8595, 7170, 7661, 7740, and 5806, recognized NPSLE with both sensitivity and specificity of 92.6%, based on training group samples, and sensitivity and specificity of 91.7% and 85.7%, respectively, based on the blind test group. In addition, the root node m/z peak 8595 protein, which was downregulated in the CSF of patients with NPSLE after treatment, was identified and confirmed as ubiquitin by immunoprecipitation and ELISA. Conclusion. Potential CSF biomarkers for NPSLE are identified by MALDI-TOF-MS combined with WCX magnetic beads. The novel diagnostic proteomic model with m/z peaks 8595, 7170, 7661, 7740, and 5806 is highly sensitive and relatively specific for NPSLE diagnosis. The level of ubiquitin in CSF is a promising biomarker for active NPSLE.