Abstract: Proteomic analysis was carried out in the cerebrospinal fluid (CSF) of patients with GuillainBarre′syndrome(GBS) and of controls to find the protein presenting the most obvious changes and to investigate its relation with GuillainBarre′syndrome. MethodsCSF was extracted from patients with GBS and controls， and proteins were precipitated with icecold acetone． Isoelectric focusing electrophoresis(IEF) was employed as the first dimension and sodium dodecylsulfatepolyacrylamide gel electrophoresis (SDSPAGE) was employed as the second dimension. The twodimensional analysis gel maps were analyzed by Imagemaster 2D software to find the obvious alteration proteins and attain the proteins in the prepared gels. The peptides mass fingerprint was obtained by MOLDI/TOF/MS, and differential proteins were identified in the SWISSPROT database. ResultsThere were 6 protein spots that had significant differences in expression between the two groups. Expressions of 4 protein spots in the GBS group increased and 2 decreased. Cystatin C which was the most significantly decreased protein was firstly discovered in this study. The subsequent ELISA confirmed that the concentration of Cystatin C was significantly lower in the GBS group than that in the control group［（2.79±0.65）vs（3.65±0.82）mg/L，P＜0.01］. Conclusion That the level of Cystatin C significantly decreases in the CSF of GBS may offer clues for studies on the mechanisms of GBS.

Key words: GuillainBarre syndrome, Cerebrospinal fluid, Proteome, Enzymelinked immunosorbent assay, Cysteine proteinase inhibitors C