Two-dimensional electrophoretic analysis of disease-associated proteins in human cerebrospinal fluid from patients with rheumatoid arthritis

Comparing protein expression in the cerebrospinal fluid (CSF) of rheumatoid arthritis (RA) patients with that of controls, makes possible the uncovering of proteins that affect disease progression and regulate responsiveness to drugs. Two-dimensional gel electrophoresis (2-DE) and silver staining were used for identifying disease-associated CSF proteins in RA patients. First, to enhance the detection of CSF proteins and to improve the separation of their isoforms by 2-DE, CSF samples were pre-treated with an albumin and IgG removal kit, then by acetone precipitation. The 2-DE analysis revealed more than 1600 spots by the removal of albumin and immunoglobulin from CSF. The expression of the protein spots was not greatly changed in either group, but some notable changes in protein spots were observed in two RA samples. In particular, the expression of an approximately 50 kD protein increased markedly, whereas that of two sequential protein spots of 10-15 kD and with neutral pI decreased in the RA samples. These preliminary results suggest that the proteomic method is conducive to clarifying the mechanism of RA crises, and that some of the expression-changed proteins may be new candidates for disease-associated proteins of RA.