Related Experiment Video
Updated: May 26, 2026
A High Throughput, Multiplexed and Targeted Proteomic CSF Assay to Quantify Neurodegenerative Biomarkers and Apolipoprotein E Isoforms Status
Published on: October 20, 2016
Validation of an alternative algorithm to oligoclonal bands. Free Light Chains in Cerebrospinal Fluid: Quantitative
María Laura Facio, Marcelo Garcia, Benjamín Baraκian
1Faculty of Pharmacy and Biochemistry, Institute of Pathophysiology and Clinical Biochemistry (INFIBIOC), University Clinical Hospital "José de San Martín", Protein Laboratory, University of Buenos Aires, Buenos Aires, Argentina.
Background:
Nearly 85% of patients with Multiple Sclerosis (MS) present oligoclonal bands (OB) by isoelectric focusing (IEF) in their cerebrospinal fluid (CSF). Currently, it is proposed to quantify free light chains (FLC), as a potential alternative for the analysis of intrathecal synthesis of immunoglobulins (ISI).
Objectives:
To study FLC in CSF/serum by qualitative/quantitative methods, in comparison with the IEF.
Methods:
Paired CSF/serum samples from 81 patients with a medical request for OB by IEF were analyzed. The FLC index was calculated: CSF/serum FLC quotient with reference to the albumin CSF/serum concentration (κ-Index and λ-Index). To analyze the dimer-monomer patterns of FLC in CSF-serum, qualitative Western blot (WB) immunoassay was performed with anti-κ and anti-λ antisera.
Results:
A cut-off limit was obtained for κ-Index=20 and λ-Index=17, sensitivity 70% and 28%; and specificity 95% and 92%, respectively. The WB was positive when a higher proportion of κ-monomer (WBκ) and/or λ-dimer (WBλ) was observed in CSF versus serum. Sensitivity for WBκ and WBλ was 80% and 82% respectively, specificity of 93% for both. The combined use of κ-Index<20 and the presence of κ-monomer and/or λ-dimer by WB increased the sensitivity to 100%.
Conclusions:
We propose analysis by WB when κ-Index<20, as an alternative algorithm to OB by IEF, for the investigation of ISI in CSF.
