Proteomics comparison of the sera from multiple sclerosis patients and neuromyelitis optica patients

This study aimed to identify the proteins that are differentially expressed in sera of multiple sclerosis (MS) patients, neuromyelitis optica (NMO) patients, and normal controls by using a two-dimensional gel electrophoresis (2-DE) assay. Serum samples were collected from the 3 groups, and total proteins were isolated and quantified by using the Bradford assay. The 2-DE and silver staining were carried out, and the Image Master 2D Platinum 5.0 software was used to analyze the images. Differentially expressed protein spots were removed from the gel and digested by enzymolysis and high-definition tandem mass spectrometry, and the MASCOT online software was applied to identify the proteins. Three differentially expressed proteins were identified: immunoglobulin (Ig) lambda chain, keratin 83, and haptoglobin (Hp2); the Ig lambda chain was only found in MS patients. The expression of keratin 83 was significantly elevated in the MS group compared to the normal control or NMO groups. The expression of Hp2 in the NMO group was elevated by more than 2-fold compared to the normal control or MS groups. In summary, a variety of proteins were found to be differentially expressed in the serum between MS, NMO, and normal subjects using 2-DE: Ig lambda, Hp2, and keratin 83 were identified as potential diagnostic markers or treatment targets for MS or NMO.