Application of an in-house method for the study of multiple sclerosis

Abstract The reference method for the biochemical study of multiple sclerosis (MS) is isoelectric focusing (IEF) and the evaluation of free light chains (FLC) could provide additional information of relevance. Therefore, it is proposed here to evaluate the presence of FLC and the applicability of the polymerisation states in the study of MS. A method consisting of a 12.5% polyacrylamide gel electrophoretic separation with a subsequent electrotransfer (PAGE-WB) was developed and the evaluation of 121 patients with suspected MS was carried out simultaneously with the IEF. MS-related PAGE-WB patterns were the increase in the concentration of Kappa monomers or Lambda dimers in CSF compared to serum. This method had a very high significance of association with the IEF (p<0.0001) with 95% sensitivity, 90% specificity, 83% PPV and 97% NPV. Intrathecal synthesis of FLC was evidenced by the increased intensity of the Kappa monomers and/or Lambda dimers observed in CSF. The PAGE-WB technique for FLC proved to be an alternative method to detect intrathecal synthesis in patients with suspected MS.