Validation of CSF free light chain in diagnosis and prognosis of multiple sclerosis and clinically isolated syndrome: prospective cohort study in Buenos Aires

• Published in: Journal of neurology 2019-01, Vol.266 (1), p.112-118
• Main Authors: Sáez, María Soledad, Rojas, Juan Ignacio, Lorenzón, María Victoria, Sánchez, Francisco, Patrucco, Liliana, Míguez, Jimena, Azcona, Carolina, Sorroche, Patricia, Cristiano, Edgardo
• Format: Article
• Language: English
• Subjects: Adult; Biomarkers - blood; Biomarkers - cerebrospinal fluid; Cerebrospinal fluid; Cohort analysis; Demyelinating Diseases - blood; Demyelinating Diseases - cerebrospinal fluid; Diagnosis; Female; Follow-Up Studies; Humans; Immunoglobulin kappa-Chains - blood; Immunoglobulin kappa-Chains - cerebrospinal fluid; Immunoglobulin lambda-Chains - blood; Immunoglobulin lambda-Chains - cerebrospinal fluid; Light chains; Male; Medicine; Medicine & Public Health; Multiple sclerosis; Neurology; Neuroradiology; Neurosciences; Original Communication; Prognosis; Prospective Studies; Sensitivity and Specificity
• ISSN: 0340-5354; 1432-1459
• DOI: 10.1007/s00415-018-9106-2

Background The objective was to evaluate the precision of kappa and lambda free light chains (KFLC and LFLC) in CSF for the diagnosis of multiple sclerosis (MS) and prognosis of clinically isolated syndrome (CIS). Methods CSF and serum samples from CIS, MS and other neurological non-MS disease were collected between 2015 and 2017. FLC concentrations were measured using immunoassay Freelite™. Results were correlated with the patients’ diagnoses and ROC curve analysis was used to determine accuracy. In CIS patients, analysis of FLC were compared in CIS converters vs. non-converter during follow-up. Results In the MS group ( n  = 41), the optimal cut-off for KFLC determined was 7 mg/L, with a diagnostic sensitivity and specificity of 95% and 97%, respectively. The optimal cut-off for LFLC was 0.7 mg/L, with a diagnostic sensitivity and specificity of 71% and 81%, respectively. 36 CIS patients were included; mean follow-up time was 28 ± 9 months, and 22 (61.1%) patients converted to MS. The median concentration of CSF K and LFLCs at CIS diagnosis was slightly higher in CIS-converters compared to non-converters, but this did not reach statistical significance (KFLC: median 7 ± 5.3 mg/L vs. 5 ± 2.3 mg/L, p  = 0.11; LFLC 0.7 ± 0.33 mg/L vs. 0.5 ± 0.23 mg/L p  = 0.16). A strong correlation was observed between the concentration of K and L FLCs at diagnosis and the change in PBVC during follow-up ( r  = 0.72 and r  = 0.65, respectively). Conclusion KFLCs have a high sensitivity and specificity for the diagnosis of MS. FLC concentrations at CIS diagnosis were not significantly higher in CIS-converters.