Free Kappa light chain in a sample of Egyptian multiple sclerosis patients (a pilot study)

Abstract

Abstract Background Multiple sclerosis is a chronic autoimmune-mediated demyelinating disease of the central nervous system that is usually associated with varying degrees of progressive disability. Free Kappa light chain (FKLC) has attracted growing attention as a significant diagnostic marker of MS. Our aim was to study the diagnostic utility of cerebrospinal fluid free Kappa light chain and related indices in a sample of Egyptian MS patients vs. CSF IgG oligoclonal bands. It was a prospective case–control study of MS patients carried in our hospital during the period from January 2021 till January 2022. Our study carried on 30 patients with multiple sclerosis and other inflammatory neurologic diseases and 20 age and sex matched controls. The study measured FKLC in the CSF and serum sample pairs of patients and control group. Indices calculated using FKLC measured in CSF and serum included; FKLC index, FKLC intrathecal fraction and quotient of FKLC. Indices were used to assess intrathecal synthesis of FKLC considering blood–CSF barrier function. Receiver operating characteristic curve analysis was used to determine diagnostic performance of FKLC and related indices in comparison to CSF–OCB testing. Results Measured FKLC levels as well as its calculated indices have shown statistically significant higher values among MS patients against OIND patients and healthy control group. Both FKLC index and FKLC IF were similarly showing 100% diagnostic sensitivity and 100% diagnostic specificity for MS diagnosis. Conclusions FKLC biomarkers are proposed to be highly sensitive and easy to detect first-line markers of intrathecal immunoglobulin synthesis with accurate performance and low cost that might prove to be promising diagnostic markers of MS.