Free light chain monomers in the diagnosis of multiple sclerosis.

A new procedure of free light chain (FLC) analysis was developed to assist the diagnosis of multiple sclerosis (MS). In this procedure, Western blotting technique was used to analyze monomeric and dimeric FLCs in the cerebrospinal fluid (CSF) and serum of patients with MS and other neurological diseases. The intensity of immunoreactive FLC bands was quantified by a specially developed software. Analysis of the obtained monomer/dimer patterns of κ and λ type FLCs allowed the determination of the diagnostically useful FLC parameters. The combined use of three FLC indices accounting for monomeric FLC-κ level and κ/λ ratio values in the CSF and serum was found to be of promising diagnostic importance for differentiation of MS from other non-MS neurological diseases.