Abstract:

Objective To study the changes of serum protein spectrum in patients with systematic lupus erythematosus （SLE） in order to screen specific protein markers. Methods Serum samples from 72 patients with SLE and 85 age- and sex-matched controls were assessed using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry （SELDI-TOF-MS） with weak cation exchange （CM10） protein chip. Forty samples from the patients and 50 control samples were randomly selected to serve as a preliminary training set; significantly different protein peaks were automatically chosen for the system training and development of a decision classification tree model. The validity of the model was then challenged with a blind test set （including another 32 samples from patients and 35 from human controls）. Results A total of 73 effective protein peaks were detected within the mass/charge ratio （m/z） interval 2000 - 50000, among which, 15 protein peaks significantly differed between patients with SLE and controls （P < 0.01）. Three protein peaks with an m/z value of 4001, 6305 and 7356 were automatically chosen as a biomarker pattern in the training set that discriminated patients with SLE from controls with a sensitivity of 90.0% （36/40）, specificity of 92.0% （46/50） and accuracy rate of 91.1% （82/90）. When the SELDI marker pattern was tested with the blinded test set, it yielded a sensitivity of 87.5% （28/32）, specificity of 91.4% （32/35） and accuracy rate of 89.6% （60/67）. Conclusions SELDI-TOF-MS protein chip could be used to screen serum protein for SLE, and the decision classification tree model with these biomarkers may favor the diagnosis of SLE.