The utility of blood–brain barrier (BBB) biomarkers for clinical and magnetic resonance imaging progression in multiple sclerosis (MS) has not been extensively investigated. To determine whether cerebrospinal fluid (CSF) measures of BBB at clinical onset predict radiological and clinical deterioration over 48 months. This longitudinal study included 182 patients after first clinical event suggestive of MS treated with weekly intramuscular interferon beta-1a. CSF and serum samples were analyzed for leukocytes, total protein, albumin, immunoglobulins, and oligoclonal bands. Optimal thresholds for the albumin quotient (QAlb) were determined. Mixed-effect model analyses, adjusted for age, gender, and treatment escalation, were used to analyze relationship between CSF measures and disease activity outcomes over 48 months of follow-up. Increased QAlb at clinical onset was associated with enlargement of lateral ventricles (p = .001) and greater whole brain (p = .003), white matter (p < .001), corpus callosum (p < .001), and thalamus (p = .003) volume loss over 48 months. Higher QAlb was associated with higher Expanded Disability Status Scale score over 48 months (p = .002). Increased QAlb at clinical onset is associated with increased brain atrophy and greater disability in patients after first clinical event suggestive of MS.

Background: Neurofilaments are the major cytoskeletal components of neurons, and cell injury leads to their release into the surrounding area. The aim of this study was to compare the cerebrospinal fluid (CSF) and serum (S) concentrations of neurofilament light chains (NFLs) and phosphorylated neurofilament heavy chains (pNFHs).Methods: Neurofilament concentrations were measured in CSF and S samples from 172 patients using three enzyme‐linked immunosorbent assays. Excel, Stata version 13, MedCal version 17.9.7., and NCSS 2007 software were used for the statistical analysis.Results: There was a statistically significant correlation between the concentrations of CSF NFL and CSF pNFH (r_s = 0.748; n = 89; P < 0.001), but Passing‐Bablok regression showed systematic deviation between the values obtained using the two assays. This indicates that the assays were not interchangeable. CSF pNFH and S pNFH concentrations showed low correlation. The kappa statistic showed moderate conformity between CSF pNFH and CSF NFL concentrations (κ = 0.556).Conclusions: The CSF NFL and CSF pNFH assays gave clinically consistent results that reflected the degree of axonal damage, independent of any particular neurological diagnosis. The S pNFH assays had a lower predictive value due to the low correlation coefficient and the kappa index of the CSF pNFH method.

We aimed to compare various methods for free light chain (fLC) quantitation in cerebrospinal fluid (CSF) and serum and to determine whether quantitative CSF measurements could reliably predict intrathecal fLC synthesis. In addition, we wished to determine the relationship between free kappa and free lambda light chain concentrations in CSF and serum in various disease groups. We analysed 166 paired CSF and serum samples by at least one of the following methods: turbidimetry (Freelite™, SPA_PLUS), nephelometry (N Latex FLC™, BN ProSpec), and two different (commercially available and in-house developed) sandwich ELISAs. The results were compared with oligoclonal fLC detected by affinity-mediated immunoblotting after isoelectric focusing. Although the correlations between quantitative methods were good, both proportional and systematic differences were discerned. However, no major differences were observed in the prediction of positive oligoclonal fLC test. Surprisingly, CSF free kappa/free lambda light chain ratios were lower than those in serum in about 75% of samples with negative oligoclonal fLC test. In about a half of patients with multiple sclerosis and clinically isolated syndrome, profoundly increased free kappa/free lambda light chain ratios were found in the CSF. Our results show that using appropriate method-specific cut-offs, different methods of CSF fLC quantitation can be used for the prediction of intrathecal fLC synthesis. The reason for unexpectedly low free kappa/free lambda light chain ratios in normal CSFs remains to be elucidated. Whereas CSF free kappa light chain concentration is increased in most patients with multiple sclerosis and clinically isolated syndrome, CSF free lambda light chain values show large interindividual variability in these patients and should be investigated further for possible immunopathological and prognostic significance.

To compare the sensitivity and specificity of CSF-restricted oligoclonal IgG and free light chains as markers of multiple sclerosis and other inflammatory neurological diseases. 196 paired CSF and serum samples were examined for oligoclonal IgG and oligoclonal free light chains. The sensitivity and specificity of the tests were calculated and optimal cut-offs for the number of CSF-restricted oligoclonal bands were then determined by analysis of receiver operating characteristic curves. Optimal cut-off values were ≥5 IgG bands for multiple sclerosis, ≥4 IgG bands for inflammatory neurological disease, ≥6 free κ, and ≥2 free λ bands for both purposes. Using these cut-off values, sensitivities and specificities for multiple sclerosis were 83.8% and 91.3% for IgG, 83.8% and 81.0% for free κ, and 67.6% and 75.4% for free λ. For inflammatory neurological disease, sensitivities and specificities were 60.8% and 95.7% for IgG, 69.6% and 92.6% for free κ, and 64.8% and 86.2% for free λ. Although exact cut-off values may vary according to method, reporting borderline results as positive, may compromise the specificity of the test and should be avoided.. The detection of intrathecal free light chain synthesis may be of value especially when the oligoclonal IgG test is negative or borderline, even though its specificity is slightly lower.

To compare cerebrospinal fluid (CSF) and serum transferrin (Tf) concentrations, transferrin quotient and index in various subgroups of MS patients. CSF and serum transferrin concentrations, transferrin quotient QTf (i.e. CSF transferrin/serum transferrin x 10(3)) and index (QTf/Qalbumin) were determined in a group of 51 patients with clinically definite or probable multiple sclerosis (MS). Patients were subdivided according to the disease form (relapsing-remitting = RR, secondary progressive = SP, primary progressive = PP; patients with RR form were further subdivided into those in the attack and those in remission), disease severity (EDSS 0-5.5, EDSS 6.0-10.0), its treatment (non-treated - including patients treated with vitamins and/ or vasodilators only, treated - i.e. glucocorticoids and/or immunosuppressants and/or (exceptionally) beta-interferon), disease duration (0-2 years, >2-10 years, > 10 years) and sex. Correlation of transferrin values with age was also performed. Serum transferrin was somewhat lower and significantly more frequently subnormal in PP patients in comparison with the SP form and the RR form in remission. Transferrin index was significantly higher in the PP form than in the RR as well as the SP form. Transferrin quotient was significantly more frequently subnormal in patients in remission compared to those in the attack of the RR disease. CSF transferrin as well as transferrin quotient were more frequently subnormal in patients with short disease duration (0-2 years) than in patients with longer disease duration; these parameters, however, correlated also significantly with age. CSF transferrin and transferrin quotient were higher in male than in female patients. The authors conclude that evaluation of transferrin in MS patients - along with albumin - may help to differentiate among various MS subgroups, since there are significant differences among RR, SP and PP forms. For this purpose, however, other CSF protein fractions should be evaluated in parallel in order to obtain more complex information and to establish a panel of examinations enabling multiple statistical analyses. Transferrin evaluation in MS may also be of significant theoretical interest, since transferrin is known to be involved in the regulation of iron metabolism and it may have a protective role against the oxidative stress. Moreover, transferrin is a growth factor important for proliferation of activated T lymphocytes. By means of the use of transferrin quotient and especially transferrin index, it may be possible to estimate the proportion of intra-CNS-synthesized transferrin and/or rate of specific transferrin transport across the blood-CSF barrier. Further studies are, however, needed for such an evaluation.