Serum neurofilament light as a biomarker in progressive multiple sclerosis

Biomarkers of tau phosphorylation state are associated with the clinical course of multiple sclerosis

BACKGROUND

Mechanisms underlying neurodegeneration in multiple sclerosis (MS) remain poorly understood but mostly implicate molecular pathways that are not unique to MS. Recently detected tau seeding activity in MS brain tissues corroborates previous neuropathological reports of hyperphosphorylated tau (p-tau) accumulation in secondary and primary progressive MS (PPMS). We aimed to investigate whether aberrant tau phosphorylation can be detected in the cerebrospinal fluid (CSF) of MS patients by using novel ultrasensitive immunoassays for different p-tau biomarkers.

METHODS

CSF samples of patients with MS (n = 55) and non-inflammatory neurological disorders (NIND, n = 31) were analysed with in-house Single molecule array (Simoa) assays targeting different tau phosphorylation sites (p-tau181, p-tau212, p-tau217 and p-tau231). Additionally, neurofilament light (NFL) and glial fibrillary acidic protein (GFAP) were measured with a multiplexed Simoa assay. Patients were diagnosed with clinically isolated syndrome (CIS, n = 10), relapsing-remitting MS (RRMS, n = 21) and PPMS (n = 24) according to the 2017 McDonald criteria and had MRI, EDSS and basic CSF analysis performed at the time of diagnosis.

RESULTS

Patients with progressive disease course had between 1.4-fold (p-tau217) and 2.2-fold (p-tau212) higher p-tau levels than relapsing MS patients (PPMS compared with CIS + RRMS, p < 0.001 for p-tau181, p-tau212, p-tau231 and p = 0.042 for p-tau217). P-tau biomarkers were associated with disease duration (ρ=0.466-0.622, p < 0.0001), age (ρ=0.318-0.485, p < 0.02, all but p-tau217) and EDSS at diagnosis and follow-up (ρ=0.309-0.440, p < 0.02). In addition, p-tau biomarkers correlated with GFAP (ρ=0.517-0.719, p ≤ 0.0001) but not with the albumin quotient, CSF cell count or NFL. Patients with higher MRI lesion load also had higher p-tau levels p ≤ 0.01 (<10 vs. ≥ 10 lesions, all p ≤ 0.01).

CONCLUSION

CSF concentrations of novel p-tau biomarkers point to a higher degree of tau phosphorylation in PPMS than in RRMS. Associations with age, disease duration and EDSS suggest this process increases with disease severity; however, replication of these results in larger cohorts is needed to further clarify the relevance of altered tau phosphorylation throughout the disease course in MS.

The ocrelizumab wearing-off phenomenon is associated with reduced immunomodulatory response and increased neuroaxonal damage in multiple sclerosis

OBJECTIVE

The wearing-off phenomenon is common in people with multiple sclerosis (MS) treated with ocrelizumab. We aim to evaluate the presence and severity of wearing-off to ocrelizumab in relation to demographic and MS clinical variables, immune profiling, and a marker of neuroaxonal damage (plasma neurofilament light chain (pNfl)).

METHODS

This cross-sectional study included MS patients treated with ocrelizumab from at least 1 year. Wearing-off questionnaire and blood samples were collected between 21 and 23 weeks after the previous ocrelizumab infusion. Lymphocyte subpopulations were evaluated on peripheral blood using flow cytometry. PNfl was evaluated using fully automated chemiluminescent enzyme immunoassay.

RESULTS

We included 106 people with MS (age 49.5 ± 11.6 years; females 42.3%; wearing-off 57.6%). On regression models, wearing-off was associated with higher pNfl, CD8, CD3, and CD3CD27 lymphocytes. Most frequent wearing-off symptoms were cognitive, sensory, and balance problems; wearing-off started < 1 week (9.4%), 1-4 weeks (10.7%) or > 4 weeks (10.7%) before infusion; 44.8% of the complaints were moderate to severe. Severity of wearing-off was associated with higher pNfl and CD8 lymphocytes.

CONCLUSIONS

Wearing-off is common in people with MS treated with ocrelizumab, and is associated with reduced immunomodulation (higher T lymphocytes) and increased neuroaxonal damage, suggesting reduced treatment response.

Serum neurofilament light chain levels are associated with depression among US adults: a cross-sectional analysis among US adults, 2013-2014

BACKGROUND

Serum neurofilament light chain (sNfL) has been identified as a biomarker for neurologic diseases. However, sNfL remains unknown to be responsible for depression.

AIMS

The aim of this research was to explore the relationship between sNfL levels and depression in US adults.

METHODS

In this cross-sectional survey of the general population, we investigated representative data involving 10,175 participants from the 2013-2014 cycle of the National Health and Nutrition Examination Survey (NHANES). Depression was diagnosed using the Patient Health Questionnaire-9 (PHQ-9). The effect of related factors on depression was analyzed by conducting a univariate analysis. Stratified analysis was utilized to detect the stability and sensitivity of the relationship. After adjusting for race, education, marital status, smoking status, body mass index (BMI), sleep duration, income, and a history of hypertension, sedentary behavior and stroke, multivariable linear regression was performed to demonstrate the correlation between sNfL and depression.

RESULTS

A total of 1301 individuals between the ages of 20 and 75 were involved in this investigation, of which 108 (8.3%) were diagnosed with depression. A significant positive correlation between sNfL and depression among adults in the US was observed by conducting univariable analyses. After adjusting for confounding factors, the multivariate analyses indicated that elevated sNfL levels might play a pivotal role in the development of depression (odds ratio (OR) = 3.0; 95% confidence interval (CI): (1.5, 6.1), P = 0.002).

CONCLUSION

These results indicated that sNfL is closely linked to depression in a nationally representative individual. However, further studies are needed to confirm the biological mechanism as well as the clinical implications of sNfL and depression.

Matching proposed clinical and MRI criteria of aggressive multiple sclerosis to serum and cerebrospinal fluid markers of neuroaxonal and glial injury

BACKGROUND

Definitions of aggressive MS employ clinical and MR imaging criteria to identify highly active, rapidly progressing disease courses. However, the degree of overlap between clinical and radiological parameters and biochemical markers of CNS injury is not fully understood. Aim of this cross-sectional study was to match clinical and MR imaging hallmarks of aggressive MS to serum/CSF markers of neuroaxonal and astroglial injury (neurofilament light chain (sNfL, cNfL), and glial fibrillary acidic protein (sGFAP, cGFAP)).

METHODS

We recruited 77 patients with relapsing-remitting MS (RRMS) and 22 patients with clinically isolated syndrome. NfL and GFAP levels in serum and CSF were assessed using a single-molecule-array HD-1-analyzer. A general linear model with each biomarker as a dependent variable was computed. Clinical and imaging criteria of aggressive MS, as recently proposed by the ECTRIMS Consensus Group, were modeled as independent variables. Other demographic, clinical or laboratory parameters, were modeled as covariates. Analyses were repeated in a homogenous subgroup, consisting only of newly diagnosed, treatment-naïve RRMS patients presenting with an acute relapse.

RESULTS

After adjusting for covariates and multiplicity of testing, sNfL and cNfL concentrations were strongly associated with the presence of ≥2 gadolinium-enhancing lesions (psNfL = 0.00008; pcNfL = 0.004) as well as the presence of infratentorial lesions on MRI (psNfL = 0.0003; pcNfL < 0.004). No other clinical and imaging criteria of aggressive MS correlated significantly with NfL or GFAP in serum and CSF. In the more homogeneous subgroup, sNfL still was associated with the presence of ≥2 gadolinium-enhancing lesions (psNfL = 0.001), presence of more than 20 T2-lesions (psNfL = 0.049) as well as the presence of infratentorial lesions on MRI (psNfL = 0.034), while cNfL was associated with the presence of ≥2 gadolinium-enhancing lesions (psNfL = 0.011) and presence of more than 20 T2-lesions (psNfL = 0.029).

CONCLUSIONS

Among proposed risk factors for an aggressive disease course, MRI findings but not clinical characteristics correlated with sNfL and cNfL as a marker of neuroaxonal injury and should be given appropriate weight considering MS prognosis and therapy. No significant correlation was detected for GFAP alone.

Serum biomarker levels predict disability progression in patients with primary progressive multiple sclerosis

BACKGROUND

We aimed to investigate the potential of serum biomarker levels to predict disability progression in a multicentric real-world cohort of patients with primary progressive multiple sclerosis (PPMS).

METHODS

A total of 141 patients with PPMS from 18 European MS centres were included. Disability progression was investigated using change in Expanded Disability Status Scale (EDSS) score over three time intervals: baseline to 2 years, 6 years and to the last follow-up. Serum levels of neurofilament light chain (sNfL), glial fibrillar acidic protein (sGFAP) and chitinase 3-like 1 (sCHI3L1) were measured using single-molecule array assays at baseline. Correlations between biomarker levels, and between biomarkers and age were quantified using Spearman's r. Univariable and multivariable linear models were performed to assess associations between biomarker levels and EDSS change over the different time periods.

RESULTS

Median (IQR) age of patients was 52.9 (46.4-58.5) years, and 58 (41.1%) were men. Median follow-up time was 9.1 (7.0-12.6) years. Only 8 (5.7%) patients received treatment during follow-up. sNfL and sGFAP levels were moderately correlated (r=0.43) and both weakly correlated with sCHI3L1 levels (r=0.19 and r=0.17, respectively). In multivariable analyses, levels of the three biomarkers were associated with EDSS changes across all time periods. However, when analysis was restricted to non-inflammatory patients according to clinical and radiological parameters (n=64), only sCHI3L1 levels remained associated with future EDSS change.

CONCLUSIONS

Levels of sNfL, sGFAP and sCHI3L1 are prognostic biomarkers associated with disability progression in patients with PPMS, being CHI3L1 findings less dependent on the inflammatory component associated with disease progression.

A rapid review of differences in cerebrospinal neurofilament light levels in clinical subtypes of progressive multiple sclerosis

Background

Multiple sclerosis (MS) is divided into three clinical phenotypes: relapsing-remitting MS (RRMS), secondary progressive MS (SPMS), and primary progressive MS (PPMS). It is unknown to what extent SPMS and PPMS pathophysiology share inflammatory or neurodegenerative pathological processes. Cerebrospinal (CSF) neurofilament light (NfL) has been broadly studied in different MS phenotypes and is a candidate biomarker for comparing MS subtypes.

Research question

Are CSF NfL levels different among clinical subtypes of progressive MS?

Methods

A search strategy identifying original research investigating fluid neurodegenerative biomarkers in progressive forms of MS between 2010 and 2022 was applied to Medline. Identified articles underwent title and abstract screen and full text review against pre-specified criteria. Data abstraction was limited to studies that measured NfL levels in the CSF. Reported statistical comparisons of NfL levels between clinical phenotypes were abstracted qualitatively.

Results

18 studies that focused on investigating direct comparisons of CSF NfL from people with MS were included in the final report. We found NfL levels were typically reported to be higher in relapsing and progressive MS compared to healthy controls. Notably, higher NfL levels were not clearly associated with progressive MS subtypes when compared to relapsing MS, and there was no observed difference in NfL levels between PPMS and SPMS in articles that separately assessed these phenotypes.

Conclusion

CSF NfL levels distinguish individuals with MS from healthy controls but do not differentiate MS subtypes. Broad biological phenotyping is needed to overcome limitations of current clinical phenotyping and improve biomarker translatability to decision-making in the clinic.

Guidance for use of neurofilament light chain as a cerebrospinal fluid and blood biomarker in multiple sclerosis management

Neurofilament light chain (NfL) is a long-awaited blood biomarker that can provide clinically useful information about prognosis and therapeutic efficacy in multiple sclerosis (MS). There is now substantial evidence for this biomarker to be used alongside magnetic resonance imaging (MRI) and clinical measures of disease progression as a decision-making tool for the management of patients with MS. Serum NfL (sNfL) has certain advantages over traditional measures of MS disease progression such as MRI because it is relatively noninvasive, inexpensive, and can be repeated frequently to monitor activity and treatment efficacy. sNfL levels can be monitored regularly in patients with MS to determine change from baseline and predict subclinical disease activity, relapse risk, and the development of gadolinium-enhancing (Gd+) lesions. sNfL does not replace MRI, which provides information related to spatial localisation and lesion stage. Laboratory platforms are starting to be made available for clinical application of sNfL in several countries. Further work is needed to resolve issues around comparisons across testing platforms (absolute values) and normalisation (reference ranges) in order to guide interpretation of the results.

Biomarker Qualification for Neurofilament Light Chain in Amyotrophic Lateral Sclerosis: Theory and Practice

OBJECTIVE

To explore whether the utility of neurofilament light chain (NfL), as a biomarker to aid amyotrophic lateral sclerosis (ALS) therapy development, would be enhanced by obtaining formal qualification from the US Food and Drug Administration for a defined context-of-use.

METHODS

Consensus discussion among academic, industry, and patient advocacy group representatives.

RESULTS

A wealth of scientific evidence supports the use of NfL as a prognostic, response, and potential safety biomarker in the broad ALS population, and as a risk/susceptibility biomarker among the subset of SOD1 pathogenic variant carriers. Although NfL has not yet been formally qualified for any of these contexts-of-use, the US Food and Drug Administration has provided accelerated approval for an SOD1-lowering antisense oligonucleotide, based partially on the recognition that a reduction in NfL is reasonably likely to predict a clinical benefit.

INTERPRETATION

The increasing incorporation of NfL into ALS therapy development plans provides evidence that its utility-as a prognostic, response, risk/susceptibility, and/or safety biomarker-is already widely accepted by the community. The willingness of the US Food and Drug Administration to base regulatory decisions on rigorous peer-reviewed data-absent formal qualification, leads us to conclude that formal qualification, despite some benefits, is not essential for ongoing and future use of NfL as a tool to aid ALS therapy development. Although the balance of considerations for and against seeking NfL biomarker qualification will undoubtedly vary across different diseases and contexts-of-use, the robustness of the published data and careful deliberations of the ALS community may offer valuable insights for other disease communities grappling with the same issues. ANN NEUROL 2024;95:211-216.

Association of magnetic resonance imaging phenotypes and serum biomarker levels with treatment response and long-term disease outcomes in multiple sclerosis patients

BACKGROUND AND PURPOSE

The aim was to evaluate whether magnetic resonance imaging (MRI) phenotypes defined by inflammation and neurodegeneration markers correlate with serum levels of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in relapsing-remitting multiple sclerosis (RRMS) patients; and to explore the role of radiological phenotypes and biomarker levels on treatment response and long-term prognostic outcomes.

METHODS

Magnetic resonance imaging scans from 80 RRMS patients were classified at baseline of interferon-beta (IFNβ) treatment into radiological phenotypes defined by high and low inflammation and high and low neurodegeneration, based on the number of contrast-enhancing lesions, brain parenchymal fraction and the relative volume of non-enhancing black holes on T1-weighted images. Serum levels of NfL and GFAP were measured at baseline with single molecule array (Simoa) assays. MRI phenotypes and serum biomarker levels were investigated for their association with IFNβ response, and times to second-line therapies, secondary-progressive MS (SPMS) conversion and Expanded Disability Status Scale (EDSS) 6.0.

RESULTS

Mean (SD) follow-up was 17 (2.9) years. Serum NfL levels and GFAP were higher in the high inflammation (p = 0.04) and high neurodegeneration phenotypes (p = 0.03), respectively. The high inflammation phenotype was associated with poor response to IFNβ treatment (p = 0.04) and with shorter time to second-line therapies (p = 0.04). In contrast, the high neurodegeneration phenotype was associated with shorter time to SPMS (p = 0.006) and a trend towards shorter time to EDSS 6.0 (p = 0.09). High serum NfL levels were associated with poor response to IFNβ treatment (p = 0.004).

CONCLUSIONS

Magnetic resonance imaging phenotypes defined by inflammation and neurodegeneration correlate with serum biomarker levels, and both have prognostic implications in treatment response and long-term disease outcomes.

Visual function resists early neurodegeneration in the visual system in primary progressive multiple sclerosis

BACKGROUND

Neurodegeneration in multiple sclerosis (MS) affects the visual system but dynamics and pathomechanisms over several years especially in primary progressive MS (PPMS) are not fully understood.

METHODS

We assessed longitudinal changes in visual function, retinal neurodegeneration using optical coherence tomography, MRI and serum NfL (sNfL) levels in a prospective PPMS cohort and matched healthy controls. We investigated the changes over time, correlations between outcomes and with loss of visual function.

RESULTS

We followed 81 patients with PPMS (mean disease duration 5.9 years) over 2.7 years on average. Retinal nerve fibre layer thickness (RNFL) was reduced in comparison with controls (90.1 vs 97.8 µm; p<0.001). Visual function quantified by the area under the log contrast sensitivity function (AULCSF) remained stable over a continuous loss of RNFL (0.46 µm/year, 95% CI 0.10 to 0.82; p=0.015) up until a mean turning point of 91 µm from which the AULCSF deteriorated. Intereye RNFL asymmetry above 6 µm, suggestive of subclinical optic neuritis, occurred in 15 patients and was related to lower AULCSF but occurred also in 5 out of 44 controls. Patients with an AULCSF progression had a faster increase in Expanded Disability Status Scale (beta=0.17/year, p=0.043). sNfL levels were elevated in patients (12.2 pg/mL vs 8.0 pg/mL, p<0.001), but remained stable during follow-up (beta=-0.14 pg/mL/year, p=0.291) and were not associated with other outcomes.

CONCLUSION

Whereas neurodegeneration in the anterior visual system is already present at onset, visual function is not impaired until a certain turning point. sNfL is not correlated with structural or functional impairment in the visual system.

Serum neurofilament light concentrations are associated with cortical thinning in anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is characterized by severe emaciation and drastic reductions of brain mass, but the underlying mechanisms remain unclear. The present study investigated the putative association between the serum-based protein markers of brain damage neurofilament light (NF-L), tau protein, and glial fibrillary acidic protein (GFAP) and cortical thinning in acute AN.

METHODS

Blood samples and magnetic resonance imaging scans were obtained from 52 predominantly adolescent, female patients with AN before and after partial weight restoration (increase in body mass index >14%). The effect of marker levels before weight gain and change in marker levels on cortical thickness (CT) was modeled at each vertex of the cortical surface using linear mixed-effect models. To test whether the observed effects were specific to AN, follow-up analyses exploring a potential general association of marker levels with CT were conducted in a female healthy control (HC) sample (n = 147).

RESULTS

In AN, higher baseline levels of NF-L, an established marker of axonal damage, were associated with lower CT in several regions, with the most prominent clusters located in bilateral temporal lobes. Tau protein and GFAP were not associated with CT. In HC, no associations between damage marker levels and CT were detected.

CONCLUSIONS

A speculative interpretation would be that cortical thinning in acute AN might be at least partially a result of axonal damage processes. Further studies should thus test the potential of serum NF-L to become a reliable, low-cost and minimally invasive marker of structural brain alterations in AN.

Transforming Drug Development for Neurological Disorders: Proceedings from a Multidisease Area Workshop

Neurological disorders represent some of the most challenging therapeutic areas for successful drug approvals. The escalating global burden of death and disability for such diseases represents a significant worldwide public health challenge, and the rate of failure of new therapies for chronic progressive disorders of the nervous system is higher relative to other non-neurological conditions. However, progress is emerging rapidly in advancing the drug development landscape in both rare and common neurodegenerative diseases. In October 2022, the Critical Path Institute (C-Path) and the US Food and Drug Administration (FDA) organized a Neuroscience Annual Workshop convening representatives from the drug development industry, academia, the patient community, government agencies, and regulatory agencies regarding the future development of tools and therapies for neurological disorders. This workshop focused on five chronic progressive diseases: Alzheimer's disease, Parkinson's disease, Huntington's disease, Duchenne muscular dystrophy, and inherited ataxias. This special conference report reviews the key points discussed during the three-day dynamic workshop, including shared learnings, and recommendations that promise to catalyze future advancement of novel therapies and drug development tools.

NfL and GFAP in serum are associated with microstructural brain damage in progressive multiple sclerosis

BACKGROUND

The potential of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) as biomarkers of disease activity and severity in progressive forms of multiple sclerosis (MS) is unclear.

OBJECTIVE

To investigate the relationship between serum concentrations of NfL, GFAP, and magnetic resonance imaging (MRI) in progressive MS.

METHODS

Serum concentrations of NfL and GFAP were measured in 32 healthy controls and 32 patients with progressive MS from whom clinical and MRI data including diffusion tensor imaging (DTI) were obtained during three years of follow-up.

RESULTS

Serum concentrations of NfL and GFAP at follow-up were higher in progressive MS patients than in healthy controls and serum NfL correlated with the EDSS score. Decreasing fractional anisotropy (FA) in normal-appearing white matter (NAWM) correlated with worsening EDSS scores and higher serum NfL. Higher serum NfL and increasing T2 lesion volume correlated with worsening paced autitory serial addition test scores. In multivariable regression analyses with serum GFAP and NfL as independent factors and DTI measures of NAWM as dependent factors, we showed that high serum NfL at follow-up was independently associated with decreasing FA and increasing MD in NAWM. Moreover, we found that high serum GFAP was independently associated with decreasing MD in NAWM and with decreasing MD and increasing FA in cortical gray matter.

CONCLUSION

Serum concentrations of NfL and GFAP are increased in progressive MS and are associated with distinct microstructural changes in NAWM and CGM.

Multimodal diagnostics in multiple sclerosis: predicting disability and conversion from relapsing-remitting to secondary progressive disease course - protocol for systematic review and meta-analysis

BACKGROUND

The number of patients diagnosed with multiple sclerosis (MS) has increased significantly over the last decade. The challenge is to identify the transition from relapsing-remitting to secondary progressive MS. Since available methods to examine patients with MS are limited, both the diagnostics and prognostication of disease progression would benefit from the multimodal approach. The latter combines the evidence obtained from disparate radiologic modalities, neurophysiological evaluation, cognitive assessment and molecular diagnostics. In this systematic review we will analyse the advantages of multimodal studies in predicting the risk of conversion to secondary progressive MS.

METHODS AND ANALYSIS

We will use peer-reviewed publications available in Web of Science, Medline/PubMed, Scopus, Embase and CINAHL databases. In vivo studies reporting the predictive value of diagnostic methods will be considered. Selected publications will be processed through Covidence software for automatic deduplication and blind screening. Two reviewers will use a predefined template to extract the data from eligible studies. We will analyse the performance metrics (1) for the classification models reflecting the risk of secondary progression: sensitivity, specificity, accuracy, area under the receiver operating characteristic curve, positive and negative predictive values; (2) for the regression models forecasting disability scores: the ratio of mean absolute error to the range of values. Then, we will create ranking charts representing performance of the algorithms for calculating disability level and MS progression. Finally, we will compare the predictive power of radiological and radiomical correlates of clinical disability and cognitive impairment in patients with MS.

ETHICS AND DISSEMINATION

The study does not require ethical approval because we will analyse publicly available literature. The project results will be published in a peer-review journal and presented at scientific conferences.

PROSPERO REGISTRATION NUMBER

CRD42022354179.

Paper-based lateral flow assay for the point-of-care detection of neurofilament light chain

Neurofilament light chain (NF-L) is a protein found in neurons of the nervous system and is widely used as a biomarker for neurological disorders. However, the current methods for detecting NF-L levels are complicated, expensive, and require specialized equipment, making it challenging to implement in a point-of-care (POC) setting. In this study, we developed a gold nanoshell (AuNS)-assisted lateral flow assay (LFA) based test strip for the POC detection of NF-L at a low ng/mL level (8 ng/mL = 117.65 pM). The test strip is a simple, rapid, and cost-effective method for detecting NF-L, making it suitable for use in a POC setting for the diagnosis and treatment of various neurological disorders. With its ease of use and reliability, the paper-based LFA is a valuable tool for the diagnosis and management of neurological conditions.Clinical Relevance- The AuNS-assisted LFA test strip developed in this study offers a rapid, cost-effective, and simple method for detecting NF-L levels, making it of great interest to practicing clinicians for the diagnosis of various neurological diseases such as HIV-associated dementia (HID), Amyotrophic Lateral Sclerosis (ALS), and Creutzfeldt-Jakob disease (CJD).

A Comparison of Two Analytical Approaches for the Quantification of Neurofilament Light Chain, a Biomarker of Axonal Damage in Multiple Sclerosis

Neurofilament light chain (NfL), is a neuron-specific cytoskeletal protein detected in extracellular fluid following axonal damage. Extensive research has focused on NfL quantification in CSF, establishing it as a prognostic biomarker of disability progression in Multiple Sclerosis (MS). Our study used a new commercially available Enzyme-Linked Immunosorbent Assay (ELISA) kit and Single Molecular Array (Simoa) advanced technology to assess serum NfL levels in MS patients and Healthy Controls (HC). Verifying the most accurate, cost-effective methodology will benefit its application in clinical settings. Blood samples were collected from 54 MS patients and 30 HC. Protocols accompanying the kits were followed. The ELISA thershold was set as 3 S.D. above the mean of the HC. For Simoa, the Z-score calculation created by Jens Kuhle's group was applied (with permission). Samples exceeding the threshold or z-score ≥1.5 indicated subclinical disease activity. To our knowledge, this is the first study to find strong-positive correlation between ELISA and Simoa for the quantification of NfL in serum (r = 0.919). Despite the strong correlation, Simoa has better analytical sensitivity and can detect small changes in samples making it valuable in clinical settings. Further research is required to evaluate whether serum NfL quantification using ELISA could be utilized to predict disability progression.

Plasma biomarkers for neurodegenerative disorders: ready for prime time?

PURPOSE OF REVIEW

Several plasma biomarkers for Alzheimer's disease and related disorders (ADRD) have demonstrated clinical and technical robustness. However, are they ready for clinical implementation? This review critically appraises current evidence for and against the immediate use of plasma biomarkers in clinical care.

RECENT FINDINGS

Plasma biomarkers have significantly improved our understanding of ADRD time-course, risk factors, diagnosis and prognosis. These advances are accelerating the development and in-human testing of therapeutic candidates, and the selection of individuals with subtle biological evidence of disease who fit the criteria for early therapeutic targeting. However, standardized tests and well validated cut-off values are lacking. Moreover, some assays (e.g., plasma Aβ methods) have poor robustness to withstand inevitable day-to-day technical variations. Additionally, recent reports suggest that common comorbidities of aging (e.g., kidney disease, diabetes, hypertension) can erroneously affect plasma biomarker levels, clinical utility and generalizability. Furthermore, it is unclear if health disparities can explain reported racial/ethnic differences in biomarker levels and functions. Finally, current clinically approved plasma methods are more expensive than CSF assays, questioning their cost effectiveness.

SUMMARY

Plasma biomarkers have biological and clinical capacity to detect ADRD. However, their widespread use requires issues around thresholds, comorbidities and diverse populations to be addressed.

Serum neurofilament light levels in natalizumab-treated patients with multiple sclerosis who switch to extended interval dosing from every-4-week dosing in real-world clinical practice

BACKGROUND

Serum levels of neurofilament light chain (sNfL) are a potentially useful biomarker for assessing the efficacy of multiple sclerosis (MS) treatments.

OBJECTIVE

To compare levels of sNfL in patients with MS who switched from natalizumab every 4 weeks (Q4W) to extended interval dosing (EID) and patients who remained on Q4W dosing in real-world clinical practice.

METHODS

This was a retrospective analysis of samples from patients treated with natalizumab from 2010 to 2015 at a single center in the United States. Levels of sNfL were compared in patients who stayed on Q4W dosing or who switched to EID (parallel-arm analyses) and during Q4W and EID periods in patients who switched to EID (pre- and post-switch analyses).

RESULTS

The analysis included 139 patients (Q4W: n = 79; EID: n = 60). After adjustment, levels of sNfL did not significantly differ between patients who remained on Q4W dosing and those who switched to EID in parallel-arm analyses (adjusted Q4W-EID difference = 0.51 pg/mL; p = 0.60) or pre- and post-switch analyses (adjusted difference = 0.96 pg/mL; p = 0.10).

CONCLUSION

These sNfL biomarker results suggest that the effectiveness of natalizumab is maintained in patients who switch from Q4W dosing to EID.

Dimethyl fumarate treatment of primary progressive multiple sclerosis: results of an open-label extension study

INTRODUCTION

Dimethyl fumarate treatment is approved in Europe for patients with relapsing-remitting multiple sclerosis (MS) and in the US for relapsing forms of MS. We recently published the results of the first randomized placebo-controlled trial of 48 weeks of treatment with dimethyl fumarate or placebo in primary progressive MS (PPMS) (clinicaltrial.gov NCT02959658). The placebo-controlled phase of the trial did not meet its primary endpoint (reduction in cerebrospinal fluid concentrations of neurofilament light chain [NFL]).

AIM

To investigate the effects of dimethyl fumarate treatment in the open-label extension phase of the trial (week 48-96), where all patients were treated with DMF.

METHODS

Reported data are from screening, week 48, and week 96 visits. Patients were clinically evaluated with Expanded Disability Status Scale (EDSS), 9-Hole Peg Test (9HPT), Timed 25-Foot Walk (T25FW) test, Symbol Digit Modalities Test (SDMT), California Verbal Learning Test, and Brief Visuospatial Memory-Revised. Serum NFL concentrations were measured by single-molecule array analysis. MRI was performed on a 3 tesla MRI scanner and included: new/enlarging lesions, volume of lesions, cortical grey matter, putamen, thalamus, and normal-appearing white matter, and additional diffusion tensor imaging and magnetization transfer ratio measures.

RESULTS

Forty-two patients entered the open-label treatment phase, and 33 patients (61%) had complete data sets at week 96. The remaining 39% did not complete the trial and were not evaluated at week 96. We found no evidence of differences in clinical and MRI measures between patients initially treated with dimethyl fumarate and patients initially treated with placebo from baseline to week 48 and from week 48-96, where all patients were treated with dimethyl fumarate. Serum NFL concentrations remained stable in both groups over 96 weeks. Assessed with either EDSS, T25FW, or 9HPT at week 96, progression was observed for 14 patients (45%). Interestingly, another 15 patients (46%) had improvement in one or more of these domains. Applying a cut-off of 8 points, 2 (6%) patients worsened on SDMT, 25 (78%) did not change, and 5 (16%) improved.

CONCLUSIONS

Dimethyl fumarate treatment showed no effects on neither clinical nor MRI outcomes or changes in serum concentrations of NFL. An expected number of patients showed evidence of progression on standard clinical scales; however, this was matched by an equal number of patients improving. The reasons for the physical improvement in an unexpectedly high proportion of patients must be addressed in future studies.

Brain-derived neurotrophic factor, neurofilament light and glial fibrillary acidic protein do not change in response to aerobic training in people with MS-related fatigue - a secondary analysis of a randomized controlled trial

BACKGROUND

Neuroinflammation and neurodegeneration are pathological hallmarks of multiple sclerosis (MS). Brain-derived neurotrophic factor (BDNF), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP) are blood-based biomarkers for neurogenesis, axonal damage and astrocyte reactivity, respectively. We hypothesize that exercise has a neuroprotective effect on MS reflected by normalization of BDNF, NfL and GFAP levels.

OBJECTIVES

To investigate the neuroprotective effect of aerobic training (AT) compared to a control intervention on blood-based biomarkers (i.e. BDNF, NfL, GFAP) in people with MS (pwMS).

METHODS

In the TREFAMS-AT (Treating Fatigue in Multiple Sclerosis - Aerobic Training) study, 89 pwMS were randomly allocated to either a 16-week AT intervention or a control intervention (3 visits to a MS nurse). In this secondary analysis, blood-based biomarker concentrations were measured in 55 patients using Simoa technology. Changes in pre- and post-intervention concentrations were compared and between-group differences were assessed using analysis of covariance (ANCOVA). Confounding effects of age, sex, MS-related disability assessed using the Expanded Disability Status Scale (EDSS), MS duration, use of disease-modifying medication, and Body Mass Index were considered.

RESULTS

Blood samples were available for 30 AT and 25 control group participants (mean age 45.6 years, 71% female, median disease duration 8 years, median EDSS score 2.5). Within-group changes in both study groups were small and non-significant, with the exception of BDNF in the control group (median (interquartile range) -2.1 (-4.7; 0)). No between-group differences were found for any biomarker: BDNF (β = 0.11, 95%CI (-3.78 to 4.00)), NfL (β = -0.04, 95%CI (-0.26 to 0.18)), and GFAP (β = -0.01, 95%CI (-0.16 to 0.15)), adjusted for confounders.

CONCLUSION

Aerobic exercise therapy did not result in statistically significant changes in the tested neuro-specific blood-based biomarkers in people with MS.

TRIAL REGISTRATION

this study is registered under number ISRCTN69520623 (https://www.isrctn.com/ISRCTN695206).

Plasma neurofilament light significantly decreases following treatment in Lyme neuroborreliosis and is not associated with persistent symptoms

BACKGROUND AND PURPOSE

Currently there is an unmet need for a highly standardized blood biomarker test to monitor treatment response in Lyme neuroborreliosis (LNB). Differentiating between active or past infection is challenged by the relatively high frequency of persistent symptoms after the end of antibiotic treatment (estimated 15%-20%), the variable clinical course and the long-lasting Borrelia burgdorferi antibodies. The aim was therefore to evaluate plasma neurofilament light chain (pNfL) as a marker for disease activity in LNB.

METHODS

This was a prospective cohort of definite LNB (N = 36) with blood samples and clinical evaluation including Glasgow Outcome Score at treatment initiation and 3 and 6 months' follow-up. Consecutive plasma was retrospectively analysed for the content of neurofilament light chain by Quanterix® kits (Simoa® NF-light Kit).

RESULTS

Plasma neurofilament light chain significantly decreased between treatment initiation and the 3-month follow-up (median 83 pg/ml vs. median 14 pg/ml (25 pairs), p < 0.0001). No significant change was observed between 3 and 6 months' follow-up (median 14 pg/ml vs. median 12 pg/ml (21 pairs), p = 0.33). At treatment initiation 90% had pNfL above the age-defined reference compared to only 23% and 7% respectively at 3 and 6 months' follow-up. Decreases in pNfL were mirrored by increasing Glasgow Outcome Score. Reporting persistent symptoms at the 6-month follow-up was not associated with pNfL (relative change from reference or actual values) at baseline or at 6 months' follow-up.

CONCLUSION

Plasma neurofilament light chain decreases following antibiotic treatment in LNB and is not associated with reporting persistent symptoms. It was therefore speculated that it may prove useful as a treatment response biomarker in LNB.

Disease-modifying therapies for relapsing/active secondary progressive multiple sclerosis - a review of population-specific evidence from randomized clinical trials

Although the understanding of secondary progressive multiple sclerosis (SPMS) is evolving, early detection of relapse-independent progression remains difficult. This is further complicated by superimposed relapses and compensatory mechanisms that allow for silent progression. The term relapsing multiple sclerosis (RMS) subsumes relapsing-remitting multiple sclerosis (RRMS) and SPMS with relapses. The latter is termed 'active' SPMS, for which disease-modifying therapies (DMTs) approved for either RMS or active SPMS can be used. However, the level of evidence supporting efficacy and safety in SPMS differs between drugs approved for RMS and SPMS. Our review aims to identify current evidence from published clinical trials and European public assessment reports from the marketing authorization procedure on the efficacy, especially on progression, of DMTs approved for RMS and SPMS. To identify relevant evidence, a literature search has been conducted and European public assessment reports of DMTs approved for RMS have been screened for unpublished data specific to SPMS. Only two clinical trials demonstrated a significant reduction in disability progression in SPMS study populations: the EXPAND study for siponimod, which included a typical SPMS population, and the European study for interferon (IFN)-beta 1b s.c., which included patients with very early and active SPMS. Both DMTs also achieved significant reductions in relapse rates. Ocrelizumab, cladribine, ofatumumab, and ponesimod are all approved for RMS - ocrelizumab, ofatumumab, and ponesimod based on an RMS study, cladribine based on an RRMS study. Data on efficacy in SPMS are only available from post hoc analyses of very small subgroups, representing only up to 15% of the total study population. For these DMTs, approval for RMS, including active SPMS, was mainly based on the assumption that the reduction in relapse rate observed in patients with RRMS can also be applied to SPMS. Based on that, the potential of these drugs to reduce relapse-independent progression remains unclear.

Demographic and disease-related factors impact on cerebrospinal fluid neurofilament light chain levels in multiple sclerosis

BACKGROUND

Neurofilament light (NfL) levels reflect inflammatory disease activity in multiple sclerosis (MS), but it is less clear if NfL also can serve as a biomarker for MS progression in treated patients without relapses and focal lesion accrual. In addition, it has not been well established if clinically effective treatment re-establishes an age and sex pattern for cerebrospinal fluid NfL (cNfL) as seen in controls, and to what degree levels are affected by disability level and magnetic resonance imaging (MRI) atrophy metrics.

METHODS

We included subjects for whom cNfL levels had been determined as per clinical routine or in clinical research, classified as healthy controls (HCs, n = 89), MS-free disease controls (DCs, n = 251), untreated MS patients (uMS; n = 296), relapse-free treated MS patients (tMS; n = 78), and ProTEct-MS clinical trial participants (pMS; n = 41).

RESULTS

Using linear regression, we found a positive association between cNfL and age, as well as lower concentrations among women, in all groups, except for uMS patients. In contrast, disability level in the entire MS cohort, or T1 and T2 lesion volumes, brain parenchymal fraction, thalamic fraction, and cortical thickness in the pMS trial cohort, did not correlate with cNfL concentrations. Furthermore, the cNfL levels in tMS and pMS groups did not differ.

CONCLUSIONS

In participants with MS lacking signs of inflammatory disease activity, disease modulatory therapy reinstates an age and sex cNfL pattern similar to that of control subjects. No significant association was found between cNfL levels and clinical worsening, disability level, or MRI metrics.

Insight into Early Diagnosis of Multiple Sclerosis by Targeting Prognostic Biomarkers

Multiple sclerosis (MS) is a central nervous system (CNS) immune-mediated disease that mainly strikes young adults and leaves them disabled. MS is an autoimmune illness that causes the immune system to attack the brain and spinal cord. The myelin sheaths, which insulate the nerve fibers, are harmed by our own immune cells, and this interferes with brain signal transmission. Numbness, tingling, mood swings, memory problems, exhaustion, agony, vision problems, and/or paralysis are just a few of the symptoms. Despite technological advancements and significant research efforts in recent years, diagnosing MS can still be difficult. Each patient's MS is distinct due to a heterogeneous and complex pathophysiology with diverse types of disease courses. There is a pressing need to identify markers that will allow for more rapid and accurate diagnosis and prognosis assessments to choose the best course of treatment for each MS patient. The cerebrospinal fluid (CSF) is an excellent source of particular indicators associated with MS pathology. CSF contains molecules that represent pathological processes such as inflammation, cellular damage, and loss of blood-brain barrier integrity. Oligoclonal bands, neurofilaments, MS-specific miRNA, lncRNA, IgG-index, and anti-aquaporin 4 antibodies are all clinically utilised indicators for CSF in MS diagnosis. In recent years, a slew of new possible biomarkers have been presented. In this review, we look at what we know about CSF molecular markers and how they can aid in the diagnosis and differentiation of different MS forms and treatment options, and monitoring and predicting disease progression, therapy response, and consequences during such opportunistic infections.

Serum GFAP and NfL Levels Differentiate Subsequent Progression and Disease Activity in Patients With Progressive Multiple Sclerosis

Background and Objectives

Neurodegeneration and astrocytic activation are pathologic hallmarks of progressive multiple sclerosis (MS) and can be quantified by serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP). We investigated sNfL and sGFAP as tools for stratifying patients with progressive MS based on progression and disease activity status.

Methods

We leveraged our Comprehensive Longitudinal Investigation of MS at the Brigham and Women's Hospital (CLIMB) natural history study, which includes clinical, MRI data and serum samples collected over more than 20 years. We included patients with MS with a confirmed Expanded Disability Status Scale (EDSS) score ≥3 that corresponds with our classifier for patients at high risk of underlying progressive pathology. We analyzed sNfL and sGFAP within 6 months from the confirmed EDSS score ≥3 corresponding with our baseline visit. Patients who further developed 6-month confirmed disability progression (6mCDP) were classified as progressors. We further stratified our patients into active/nonactive based on new brain/spinal cord lesions or relapses in the 2 years before baseline or during follow-up. Statistical analysis on log-transformed sGFAP/sNfL assessed the baseline association with demographic, clinical, and MRI features and associations with future disability.

Results

We included 257 patients with MS who had an average EDSS score of 4.0 and a median follow-up after baseline of 7.6 years. sNfL was higher in patients with disease activity in the 2 years before baseline (adjusted β = 1.21; 95% CI 1.04–1.42;p= 0.016), during the first 2 years of follow-up (adjusted β = 1.17; 95% CI = 1.01–1.36;p= 0.042). sGFAP was not increased in the presence of disease activity. Higher sGFAP levels, but not sNfL levels, were associated with higher risk of 6mCDP (adjusted hazard ratio [HR] = 1.71; 95% CI = 1.19–2.45;p= 0.004). The association was stronger in patients with low sNfL (adjusted HR = 2.44; 95% CI 1.32–4.52;p= 0.005) and patients who were nonactive in the 2 years prior or after the sample.

Discussion

Higher levels of sGFAP correlated with subsequent progression, particularly in nonactive patients, whereas sNfL reflected acute disease activity in patients with MS at high risk of underlying progressive pathology. Thus, sGFAP and sNfL levels may be used to stratify patients with progressive MS for clinical research studies and clinical trials and may inform clinical care.

Serum neurofilament-light and glial fibrillary acidic protein levels in hydroxychloroquine-treated primary progressive multiple sclerosis

BACKGROUND

In a recent trial, hydroxychloroquine (HCQ) treatment reduced the expected rate of disability worsening at 18 months in primary progressive multiple sclerosis (PPMS). Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) are emerging biomarkers in multiple sclerosis.

METHODS

We measured NfL and GFAP levels in serum samples from 39 patients with inactive PPMS included in a phase II clinical trial of HCQ treatment in PPMS at multiple time points over 18 months, and investigated the association of these biomarkers with clinical disability at screening and during follow-up. Screening and 12-month retinal nerve fiber layer (RNFL) thickness was also recorded and analyzed.

RESULTS

NfL and GFAP levels increased over time, but only significantly from screening to month 6. NfL and GFAP levels did not significantly increase from month 6 up to month 18. At screening, NfL and GFAP levels did not correlate with the Expanded Disability Status Scale (EDSS), and GFAP but not NfL modestly correlated with Timed 25-Foot Walk test (T25FW). Screening NfL and GFAP levels did not predict disability worsening (≥20% worsening on the T25FW) at month 18. RNFL thickness decreased significantly from screening to month 12 and independently predicted disability worsening.

CONCLUSIONS

In this cohort of people with inactive PPMS, HCQ treatment attenuated the increase of NfL and GFAP after 6 months of treatment and up to 18 months of follow-up, suggesting a treatment effect of HCQ over these biomarkers. RNFL thickness, a marker of neuroaxonal atrophy, was associated with disability worsening, and should be explored further as a prognostic marker in this population.

Evaluation of neurotrophic factor secreting mesenchymal stem cells in progressive multiple sclerosis

BACKGROUND

Autologous mesenchymal stem cell neurotrophic factor-secreting cells (NurOwn^®) have the potential to modify underlying disease mechanisms in progressive multiple sclerosis (PMS).

OBJECTIVE

This open-label phase II study was conducted to evaluate safety/efficacy of three intrathecal cell treatments.

METHODS

Eighteen participants with non-relapsing PMS were treated. The primary endpoint was safety. Secondary endpoints included: cerebrospinal fluid (CSF) biomarkers; timed 25-foot walk speed, nine-hole peg test (9-HPT), low-contrast letter acuity, symbol digit modalities test, and 12-item multiple sclerosis (MS) walking scale. Seventeen participants received all treatments.

RESULTS

No deaths/adverse events related to worsening of MS, clinical/magnetic resonance imaging (MRI) evidence of disease activation, and clinically significant changes in safety lab results were reported. Two participants developed symptoms of low back and leg pain, consistent with a diagnosis of arachnoiditis, occurring in one of three intrathecal treatments in both participants. Nineteen percent of treated participants achieved pre-specified ⩾ 25% improvements in timed 25-foot walk speed/nine-HPT at 28 weeks compared to baseline, along with consistent efficacy signals for pre-specified response criteria across other secondary efficacy outcomes. CSF neuroprotective factors increased, and inflammatory biomarkers decreased after treatment, consistent with the proposed mechanism of action.

CONCLUSION

Based on these encouraging preliminary findings, further confirmation in a randomized study is warranted.

Neurodegeneration in multiple sclerosis

Axonal loss in multiple sclerosis (MS) is a key component of disease progression and permanent neurologic disability. MS is a heterogeneous demyelinating and neurodegenerative disease of the central nervous system (CNS) with varying presentation, disease courses, and prognosis. Immunomodulatory therapies reduce the frequency and severity of inflammatory demyelinating events that are a hallmark of MS, but there is minimal therapy to treat progressive disease and there is no cure. Data from patients with MS, post-mortem histological analysis, and animal models of demyelinating disease have elucidated patterns of MS pathogenesis and underlying mechanisms of neurodegeneration. MRI and molecular biomarkers have been proposed to identify predictors of neurodegeneration and risk factors for disease progression. Early signs of axonal dysfunction have come to light including impaired mitochondrial trafficking, structural axonal changes, and synaptic alterations. With sustained inflammation as well as impaired remyelination, axons succumb to degeneration contributing to CNS atrophy and worsening of disease. These studies highlight the role of chronic demyelination in the CNS in perpetuating axonal loss, and the difficulty in promoting remyelination and repair amidst persistent inflammatory insult. Regenerative and neuroprotective strategies are essential to overcome this barrier, with early intervention being critical to rescue axonal integrity and function. The clinical and basic research studies discussed in this review have set the stage for identifying key propagators of neurodegeneration in MS, leading the way for neuroprotective therapeutic development. This article is categorized under: Immune System Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology.

The role of neurofilament light in genetic frontotemporal lobar degeneration

Genetic frontotemporal lobar degeneration caused by autosomal dominant gene mutations provides an opportunity for targeted drug development in a highly complex and clinically heterogeneous dementia. These neurodegenerative disorders can affect adults in their middle years, progress quickly relative to other dementias, are uniformly fatal and have no approved disease-modifying treatments. Frontotemporal dementia, caused by mutations in the GRN gene which encodes the protein progranulin, is an active area of interventional drug trials that are testing multiple strategies to restore progranulin protein deficiency. These and other trials are also examining neurofilament light as a potential biomarker of disease activity and disease progression and as a therapeutic endpoint based on the assumption that cerebrospinal fluid and blood neurofilament light levels are a surrogate for neuroaxonal damage. Reports from genetic frontotemporal dementia longitudinal studies indicate that elevated concentrations of blood neurofilament light reflect disease severity and are associated with faster brain atrophy. To better inform patient stratification and treatment response in current and upcoming clinical trials, a more nuanced interpretation of neurofilament light as a biomarker of neurodegeneration is now required, one that takes into account its relationship to other pathophysiological and topographic biomarkers of disease progression from early presymptomatic to later clinically symptomatic stages.

Secondary Progressive Multiple Sclerosis

Many challenges exist in the precise diagnosis and clinical management of secondary progressive multiple sclerosis (SPMS) because of the lack of definitive clinical, imaging, immunologic, or pathologic criteria that demarcate the transition from relapsing-remitting MS to SPMS. This review provides an overview of the diagnostic criteria/definition and the heterogeneity associated with different SPMS patient populations; it also emphasizes the importance of available prospective/retrospective tools to identify patients with SPMS earlier in the disease course so that approved disease-modifying therapies and nonpharmacological strategies will translate into better outcomes. Delivery of such interventions necessitates an evolving patient-clinician dialog within the context of a multidisciplinary team.

Neuroaxonal and Glial Markers in Patients of the Same Age With Multiple Sclerosis

BACKGROUND AND OBJECTIVES

The specificity of novel blood biomarkers for multiple sclerosis (MS)-related neurodegeneration is unclear because neurodegeneration also occurs during normal aging. To understand which aspects of neurodegeneration the serum biomarkers neurofilament light (sNfL), serum glial fibrillary acidic protein (sGFAP), and serum contactin-1 (sCNTN1) reflect, we here explore their cross-sectional association with disability outcome measures and MRI volumes in a unique cohort of people with MS (PwMS) of the same age.

METHODS

sNfL, sGFAP (both singe-molecule array technology) and sCNTN1 (Luminex) were measured in serum samples of 288 PwMS and 125 healthy controls (HCs) of the Project Y cohort, a population-based cross-sectional study of PwMS born in the Netherlands in 1966 and age-matched HC.

RESULTS

sNfL (9.83 pg/mL [interquartile range {IQR}: 7.8-12.0]) and sGFAP (63.7 pg/mL [IQR: 48.5-84.5]) were higher in PwMS compared with HC (sNfL: 8.8 pg/mL [IQR: 7.0-10.5]; sGFAP: 51.7 pg/mL [IQR: 40.1-68.3]) (p < 0.001), whereas contactin-1 (7,461.3 pg/mL [IQR: 5,951.8-9,488.6]) did not significantly differ between PwMS compared with HC (7,891.2 pg/mL [IQR: 6,120.0-10,265.8]) (p = 0.068). sNfL and sGFAP levels were 1.2-fold higher in secondary progressive patients (SPMS) compared with relapsing remitting patients (p = 0.009 and p = 0.043). Stratified by MS subtype, no relations were seen for CNTN1, whereas sNfL and sGFAP correlated with the Expanded Disability Status Scale (ρ = 0.43 and ρ = 0.39), Nine-Hole Peg Test, Timed 25-Foot Walk Test, and Symbol Digit Modalities Test (average ρ = 0.38) only in patients with SPMS. Parallel to these clinical findings, correlations were only found for sNfL and sGFAP with MRI volumes. The strongest correlations were observed between sNfL and thalamic volume (ρ = -0.52) and between sGFAP with deep gray matter volume (ρ = - 0.56) in primary progressive patients.

DISCUSSION

In our cohort of patients of the same age, we report consistent correlations of sNfL and sGFAP with a range of metrics, especially in progressive MS, whereas contactin-1 was not related to clinical or MRI measures. This demonstrates the potential of sNfL and sGFAP as complementary biomarkers of neurodegeneration, reflected by disability, in progressive MS.

Neurofilament light chain levels predict encephalopathy and outcome in community-acquired pneumonia

OBJECTIVE

Serum neurofilament light chain (sNfL) is a biomarker for neuroaxonal damage and has been found to be elevated in several neurological diseases with neuronal destruction. New onset of confusion is a hallmark of severity in infections. The objective of this study was to determine whether sNfL levels are increased in patients with community-acquired pneumonia (CAP) and if increased sNfL levels are associated with disease-associated confusion or disease severity.

METHODS

In this observational study, sNfL levels were determined with single-molecule array technology in CAP patients of the CAPNETZ cohort with validated CRB (confusion, respiratory rate, and blood pressure)-65 score. We determined associations between log-transformed sNfL concentrations, well-defined clinical characteristics, and unfavorable outcome in multivariable analyses. Receiver operating characteristic (ROC) analysis was performed to assess the prediction accuracy of sNfL levels for confusion in CAP patients.

RESULTS

sNfL concentrations were evaluated in 150 CAP patients. Patients with confusion had higher sNfL levels as compared to non-confusion patients of comparable overall disease severity. ROC analysis of sNfL and confusion provided an area under the curve (AUC) of 0.73 (95% CI 0.62-0.82). Log-transformed sNfL levels were not associated with general disease severity. In a logistic regression analysis, log2-sNfL was identified as a strong predictor for an unfavorable outcome.

INTERPRETATION

sNfL levels are specifically associated with confusion and not with pneumonia disease severity, thus reflecting a potential objective marker for encephalopathy in these patients. Furthermore, sNfL levels are also associated with unfavorable outcome in these patients and might help clinicians to identify patients at risk.

Serum Neurofilament Identifies Patients With Multiple Sclerosis With Severe Focal Axonal Damage in a 6-Year Longitudinal Cohort

BACKGROUND AND OBJECTIVES

Immunomodulatory therapies reduce the relapse rate but only marginally control disability progression in patients with MS. Although serum neurofilament light chain (sNfL) levels correlate best with acute signs of inflammation (e.g., relapses and gadolinium-enhancing [Gd+] lesions), their role in predicting progressive biology and irreversible axonal damage is less clear. We aimed to determine the ability of sNfL to dissect distinct measures of disease severity and predict future (no) evidence of disease activity (EDA/no evidence of disease activity [NEDA]).

METHODS

One hundred fifty-three of 221 patients with relapsing-remitting MS initially enrolled in the Neurofilament and longterm outcome in MS cohort at the MS outpatient clinic of the University Medical Center Mainz (Germany) met the inclusion criteria for this prospective observational cohort study with a median follow-up of 6 years (interquartile range 4-7 years). Progressive disease forms were excluded. Inclusion criteria consisted of Expanded Disability Status Scale (EDSS) assessment within 3 months and MRI within 12 months around blood sampling at baseline (y0) and follow-up (y6). EDSS progression at y6 had to be confirmed 12 weeks later. sNfL was measured by single-molecule array, and the following additional variables were recorded: therapy, medical history, and detailed MRI parameters (T2 hyperintense lesions, Gd+ lesions, and new persistent T1 hypointense lesions).

RESULTS

Patients experiencing EDSS progression or new persistent T1 lesions at y6 showed increased sNfL levels at y0 compared with stable patients or patients with inflammatory activity only. As a potential readily accessible marker of neurodegeneration, we incorporated the absence of persistent T1 lesions to the NEDA-3 concept (NEDA-3^T1: n = 54, 35.3%; EDA^T1: n = 99, 64.7%) and then evaluated a risk score with factors that distinguish patients with and without NEDA-3^T1 status. Adding sNfL to this risk score significantly improved NEDA-3^T1 prediction (0.697 95% CI 0.616-0.770 vs 0.819 95% CI 0.747-0.878, p < 0.001). Patients with sNfL values ≤8.6 pg/mL showed a 76% risk reduction for EDA^T1 at y6 (hazard ratio 0.244, 95% CI 0.142-0.419, p < 0.001).

DISCUSSION

sNfL levels associate with severe focal axonal damage as reflected by development of persistent T1 lesions. Baseline sNfL values predicted NEDA-3^T1 status at 6-year follow-up.

Ella versus Simoa Serum Neurofilament Assessment to Monitor Treatment Response in Highly Active Multiple Sclerosis Patients

The measurement of serum neurofilament light chain (sNfL) is of growing importance in the field of neurology. In the management of multiple sclerosis, it can serve as a useful marker to assess disease activity and treatment response. This paper compares two available methods, namely the Single Molecule Array (Simoa) and the Ella microfluid platform, to measure longitudinal sNfL levels of 42 highly active multiple sclerosis patients treated with alemtuzumab over a period of 36 months. In order to assess the methods agreement, Bland-Altman plots and Passing-Bablok regression were analyzed. Here, we show that despite the fact that Ella measures around 24% higher values than Simoa, both are equally suitable for longitudinal sNfL monitoring.

Neurofilament-light and contactin-1 association with long-term brain atrophy in natalizumab-treated relapsing-remitting multiple sclerosis

BACKGROUND

Despite highly effective treatment strategies for patients with relapsing-remitting multiple sclerosis (RRMS), long-term neurodegeneration and disease progression are often considerable. Accurate blood-based biomarkers that predict long-term neurodegeneration are lacking.

OBJECTIVE

To assess the predictive value of serum neurofilament-light (sNfL) and serum contactin-1 (sCNTN1) for long-term magnetic resonance imaging (MRI)-derived neurodegeneration in natalizumab-treated patients with RRMS.

METHODS

sNfL and sCNTN1 were measured in an observational cohort of natalizumab-treated patients with RRMS at baseline (first dose) and at 3 months, Year 1, Year 2, and last follow-up (median = 5.2 years) of treatment. Disability progression was quantified using "EDSS-plus" criteria. Neurodegeneration was measured by calculating annualized percentage brain, ventricular, and thalamic volume change (PBVC, VVC, and TVC, respectively). Linear regression analysis was performed to identify longitudinal predictors of neurodegeneration.

RESULTS

In total, 88 patients (age = 37 ± 9 years, 75% female) were included, of whom 48% progressed. Year 1 sNfL level (not baseline or 3 months) was associated with PBVC (standardized (std.) β = -0.26, p = 0.013), VVC (standardized β = 0.36, p < 0.001), and TVC (standardized β = -0.24, p = 0.02). For sCNTN1, only 3-month level was associated with VVC (standardized β = -0.31, p = 0.002).

CONCLUSION

Year 1 (but not baseline) sNfL level was predictive for long-term brain atrophy in patients treated with natalizumab. sCNTN1 level did not show a clear predictive value.

Neurofilament light chain in central nervous system infections: a prospective study of diagnostic accuracy

Diagnosing central nervous system (CNS) infections quickly is often difficult. Neurofilament light chain (NfL) is a component of the axonal cytoskeleton and identified as marker of neuronal damage in several CNS diseases. We evaluated the diagnostic accuracy of NfL for diagnosing CNS infections. We included patients from a prospective cohort of consecutive patients in whom a lumbar puncture was performed for suspected CNS infection in an academic hospital in The Netherlands. The index test was NfL in cerebrospinal fluid (CSF) and reference standard the final clinical diagnosis. Diagnostic accuracy was determined using the area-under-the-curve (AUC) with 95% confidence intervals (CI). The association of CSF NfL with clinical characteristics, diagnosis and outcome was evaluated. Between 2012 and 2015, 273 episodes in adults of which sufficient CSF was available were included. CNS infection was diagnosed in 26%(n = 70), CNS inflammatory disease in 7%(n = 20), systemic infection in 32%(n = 87), and other neurological disorders in 33%(n = 90). Median CSF NfL level was 593 pg/ml (IQR 249–1569) and did not discriminate between diagnostic categories or CNS infection subcategories. AUC for diagnosing any CNS infection compared to patients without CNS infections was 0.50 (95% CI 0.42–0.59). Patients presenting with an altered mental status had higher NfL levels compared to other patients. We concluded that NfL cannot discriminate between causes in patients suspected of CNS infections. High concentrations of NfL are associated with severe neurological disease and the prognostic value of NfL in patients with CNS infections should be investigated in future research.

Association of Serum Neurofilament Light Chain With Inner Retinal Layer Thinning in Multiple Sclerosis

BACKGROUND AND OBJECTIVES

Serum neurofilament light chain (sNfL) and optical coherence tomography (OCT)-derived retinal measures (including peripapillary retinal nerve fiber layer [pRNFL] and macular ganglion cell layer/inner plexiform layer [GCIPL] thickness) have been proposed as biomarkers of neurodegeneration in multiple sclerosis (MS). However, studies evaluating the associations between sNfL and OCT-derived retinal measures in MS are limited.

METHODS

In this retrospective analysis of a longitudinal, observational, single-center cohort study, sNfL levels were measured in people with MS and healthy controls (HCs) using single molecule array. Participants with MS were followed with serial OCT for a median follow-up of 4.5 years. Eyes with optic neuritis (ON) within 6 months of baseline OCT or ON during follow-up were excluded. Age-normative cutoffs of sNfL were derived using the HC data, and MS participants with sNfL greater than the 97.5th percentile for age were classified as having elevated sNfL (sNfL-E). Analyses were performed with mixed-effects linear regression models and adjusted for age, sex, race, and history of ON.

RESULTS

A total of 130 HCs (age: 42.4 ± 14.2 years; 62% female) and 403 people with MS (age: 43.1 ± 12.0 years; 78% female) were included. Elevated sNfL levels were present at baseline in 80 participants with MS (19.9%). At baseline, sNfL-E participants had modestly lower pRNFL (-3.03 ± 1.50 μm; p = 0.044) and GCIPL thickness (-2.74 ± 1.02 μm; p = 0.007). As compared with those with sNfL within the reference range, eyes from NfL-E participants exhibited faster longitudinal thinning of the pRNFL (45% faster; -0.74 vs -0.51 μm/y; p = 0.015) and GCIPL (25% faster; -0.35 vs -0.28 μm/y; p = 0.021). Significant differences in rates of pRNFL and GCIPL thinning between sNfL groups were found only in those with relapsing-remitting MS but not progressive MS.

DISCUSSION

Elevated baseline sNfL is associated with accelerated rates of retinal neuroaxonal loss in relapsing-remitting MS, independent of overt ON, but may be less reflective of retinal neurodegeneration in progressive MS.

Progressive Multiple Sclerosis

PURPOSE OF REVIEW

This article provides an update on progressive forms of multiple sclerosis (MS) commonly referred to as primary progressive MS and secondary progressive MS. It discusses the importance of diagnosing and detecting progression early, the similarities between progressive forms, challenges in detecting progression, factors that could augment progression, and the importance of disease-modifying therapies in patients with evidence of active progressive MS. It also discusses the overall care of progressive MS.

RECENT FINDINGS

The pathogenesis of primary progressive MS and secondary progressive MS is overlapping, and in both presentations, patients with relapses or focal MRI activity are classified as having active, progressive MS. All currently approved disease-modifying therapies are indicated for active secondary progressive MS. The therapeutic opportunity of anti-inflammatory drugs for the treatment of progressive MS is enhanced in those who are younger and have a shorter disease duration. Vascular comorbidities may contribute to progression in MS.

SUMMARY

Several challenges remain in the diagnosis, follow-up, and treatment of progressive MS. Early identification of active progressive MS is needed to maximize treatment benefit. The advantages of optimal comorbidity management (eg, hypertension, hyperlipidemia) in delaying progression are uncertain. Clinical care guidelines for advanced, severe MS are lacking.

Diagnosis of Multiple Sclerosis

PURPOSE OF REVIEW

The diagnosis of multiple sclerosis (MS) can be made based on clinical symptoms and signs alone or a combination of clinical and paraclinical features. Diagnostic criteria for MS have evolved over time, and the latest version facilitates earlier diagnosis of MS in those presenting with typical clinical syndromes. This article summarizes the current diagnostic criteria for MS, typical and atypical presentations of MS, and when diagnostic criteria should be applied with caution.

RECENT FINDINGS

The most recent version of the MS diagnostic criteria has the benefits of simplicity and greater sensitivity in comparison to previous iterations. However, misdiagnosis remains a significant issue in MS clinical care, even at MS specialty centers. It is, therefore, evident that careful clinical application of the current version of the diagnostic criteria is necessary and that tools improving the diagnostic accuracy of MS would be of substantial clinical utility. Emerging diagnostic biomarkers that may be useful in this regard, including the central vein sign, paramagnetic rim lesions, and fluid biomarkers, are discussed.

SUMMARY

Current MS diagnostic criteria facilitate the early diagnosis of MS in people presenting with typical clinical syndromes but should be used cautiously in those presenting with atypical syndromes and in special populations. Clinical judgment and existing paraclinical tools, including sequential MRIs of the neuraxis and laboratory tests, are useful in minimizing misdiagnosis and facilitating the accurate diagnosis of MS. Diagnostic biomarkers that may facilitate or refute a diagnosis of MS in these settings, and emerging imaging and fluid biomarkers may eventually become available for use in clinical settings.

Multidimensional overview of neurofilament light chain contribution to comprehensively understanding multiple sclerosis

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease characterized by demyelination, progressive axonal loss, and varying clinical presentations. Axonal damage associated with the inflammatory process causes neurofilaments, the major neuron structural proteins, to be released into the extracellular space, reaching the cerebrospinal fluid (CSF) and the peripheral blood. Methodological advances in neurofilaments’ serological detection and imaging technology, along with many clinical and therapeutic studies in the last years, have deepened our understanding of MS immunopathogenesis. This review examines the use of light chain neurofilaments (NFLs) as peripheral MS biomarkers in light of the current clinical and therapeutic evidence, MS immunopathology, and technological advances in diagnostic tools. It aims to highlight NFL multidimensional value as a reliable MS biomarker with a diagnostic-prognostic profile while improving our comprehension of inflammatory neurodegenerative processes, mainly RRMS, the most frequent clinical presentation of MS.

MSProDiscuss™ Clinical Decision Support Tool for Identifying Multiple Sclerosis Progression

This article describes the rationale for the development of the MSProDiscuss™ clinical decision support (CDS) tool, its development, and insights into how it can help neurologists improve care for patients with multiple sclerosis (MS). MS is a progressive disease characterized by heterogeneous symptoms and variable disease course. There is growing consensus that MS exists on a continuum, with overlap between relapsing–remitting and secondary progressive phenotypes. Evidence demonstrates that neuroaxonal loss occurs from the outset, that progression can occur independent of relapse activity, and that continuous underlying pathological processes may not be reflected by inflammatory activity indicative of the patient’s immune response. Early intervention can benefit patients, and there is a need for a tool that assists physicians in rapidly identifying subtle signs of MS progression. MSProDiscuss, developed with physicians and patients, facilitates a structured approach to patient consultations. It analyzes multidimensional data via an algorithm to estimate the likelihood of progression (the MSProDiscuss score), the contribution of various symptoms, and the impact of symptoms on daily living, enabling a more personalized approach to treatment and disease management. Data from CDS tools such as MSProDiscuss offer new insights into disease course and facilitate informed decision-making and a holistic approach to MS patient care.

Comparative Analysis of Neurodegeneration and Axonal Dysfunction Biomarkers in the Cerebrospinal Fluid of Patients with Multiple Sclerosis

BACKGROUND

Given the significant role of neurodegeneration in the progression of multiple sclerosis (MS) and insufficient therapies, there is an urgent need to better understand this pathology and to find new biomarkers that could provide important insight into the biological mechanisms of the disease. Thus, the present study aimed to compare different neurodegeneration and axonal dysfunction biomarkers in MS and verify their potential clinical usefulness.

METHODS

A total of 59 patients, who underwent CSF analysis during their diagnostics, were enrolled in the study. Quantitative analysis of neurodegeneration biomarkers was performed through immunological tests. Oligoclonal bands were detected by isoelectric focusing on agarose gel, whereas the concentrations of immunoglobulins and albumin were measured using nephelometry.

RESULTS

Our studies showed that NfL, RTN4, and tau protein enabled the differentiation of MS patients from the control group. Additionally, the baseline CSF NfL levels positively correlated with the tau and MRI results, whereas the RTN4 concentrations were associated with the immunoglobulin quotients. The AUC for NfL was the highest among the tested proteins, although the DeLong test of the ROC curves showed no significant difference between the AUCs for NfL and RTN4.

CONCLUSION

The CSF NfL, RTN-4, and tau levels at the time of diagnosis could be potential diagnostic markers of multiple sclerosis, although NfL seems to have the best clinical value.

Age-dependent gray matter demyelination is associated with leptomeningeal neutrophil accumulation

People living with multiple sclerosis (MS) experience episodic CNS white matter lesions instigated by autoreactive T cells. With age, patients with MS show evidence of gray matter demyelination and experience devastating nonremitting symptomology. What drives progression is unclear and studying this has been hampered by the lack of suitable animal models. Here, we show that passive experimental autoimmune encephalomyelitis (EAE) induced by an adoptive transfer of young Th17 cells induced a nonremitting clinical phenotype that was associated with persistent leptomeningeal inflammation and cortical pathology in old, but not young, SJL/J mice. Although the quantity and quality of T cells did not differ in the brains of old versus young EAE mice, an increase in neutrophils and a decrease in B cells were observed in the brains of old mice. Neutrophils were also found in the leptomeninges of a subset of progressive MS patient brains that showed evidence of leptomeningeal inflammation and subpial cortical demyelination. Taken together, our data show that while Th17 cells initiate CNS inflammation, subsequent clinical symptoms and gray matter pathology are dictated by age and associated with other immune cells, such as neutrophils.

Progression in multiple sclerosis - a long-term problem

PURPOSE OF REVIEW

Disability progression in multiple sclerosis (MS) is strongly linked to central nervous system (CNS)-specific pathological processes that occur throughout all disease stages, but that become clinically evident in later phases of the disease. We here discuss current views and concepts for targeting progressive MS.

RECENT FINDINGS

Detailed clinical assessment of MS patients has identified an even closer entanglement of relapse-remitting and progressive disease, leading to novel concepts such as 'progression independent of relapse activity'. Evolving clinical concepts together with a focus on molecular (neurofilament light chain) and imaging (paramagnetic rim lesions) biomarkers might specifically identify patients at risk of developing progressive MS considerably earlier than before. A multitude of novel treatment approaches focus either on direct neuroaxonal protection or myelin regeneration or on beneficially modulating CNS-intrinsic or innate immune inflammation. Although some long-awaited trials have recently been unsuccessful, important lessons could still be drawn from novel trial designs providing frameworks for future clinical studies.

SUMMARY

Targeting progressive disease biology and repairing established damage is the current central challenge in the field of MS. Especially, the compartmentalized adaptive and innate CNS inflammation is an attractive target for novel approaches, probably as a combinatory approach together with neuroprotective or myelin regenerating strategies.

Towards a Better Understanding of the Atypical Features of Chronic Graft-Versus-Host Disease: A Report from the 2020 National Institutes of Health Consensus Project Task Force

Alloreactive and autoimmune responses after allogeneic hematopoietic cell transplantation can occur in non-classical chronic graft-versus-host disease (chronic GVHD) tissues and organ systems or manifest in atypical ways in classical organs commonly affected by chronic GVHD. The National Institutes of Health (NIH) consensus projects were developed to improve understanding and classification of the clinical features and diagnostic criteria for chronic GVHD. While still speculative whether atypical manifestations are entirely due to chronic GVHD, these manifestations remain poorly captured by the current NIH consensus project criteria. Examples include chronic GVHD impacting the hematopoietic system as immune mediated cytopenias, endothelial dysfunction, or as atypical features in the musculoskeletal system, central and peripheral nervous system, kidneys, and serous membranes. These purported chronic GVHD features may contribute significantly to patient morbidity and mortality. Most of the atypical chronic GVHD features have received little study, particularly within multi-institutional and prospective studies, limiting our understanding of their frequency, pathogenesis, and relation to chronic GVHD. This NIH consensus project task force report provides an update on what is known and not known about the atypical manifestations of chronic GVHD, while outlining a research framework for future studies to be undertaken within the next three to seven years. We also provide provisional diagnostic criteria for each atypical manifestation, along with practical investigation strategies for clinicians managing patients with atypical chronic GVHD features.

Focus on the Role of the NLRP3 Inflammasome in Multiple Sclerosis: Pathogenesis, Diagnosis, and Therapeutics

Neuroinflammation is initiated with an aberrant innate immune response in the central nervous system (CNS) and is involved in many neurological diseases. Inflammasomes are intracellular multiprotein complexes that can be used as platforms to induce the maturation and secretion of proinflammatory cytokines and pyroptosis, thus playing a pivotal role in neuroinflammation. Among the inflammasomes, the nucleotide-binding oligomerization domain-, leucine-rich repeat- and pyrin domain-containing 3 (NLRP3) inflammasome is well-characterized and contributes to many neurological diseases, such as multiple sclerosis (MS), Alzheimer's disease (AD), and ischemic stroke. MS is a chronic autoimmune disease of the CNS, and its hallmarks include chronic inflammation, demyelination, and neurodegeneration. Studies have demonstrated a relationship between MS and the NLRP3 inflammasome. To date, the pathogenesis of MS is not fully understood, and clinical studies on novel therapies are still underway. Here, we review the activation mechanism of the NLRP3 inflammasome, its role in MS, and therapies targeting related molecules, which may be beneficial in MS.

Serum-Based Biomarkers in Neurodegeneration and Multiple Sclerosis

Multiple Sclerosis (MS) is a debilitating disease with typical onset between 20 and 40 years of age, so the disability associated with this disease, unfortunately, occurs in the prime of life. At a very early stage of MS, the relapsing-remitting mobility impairment occurs in parallel with a progressive decline in cognition, which is subclinical. This stage of the disease is considered the beginning of progressive MS. Understanding where a patient is along such a subclinical phase could be critical for therapeutic efficacy and enrollment in clinical trials to test drugs targeted at neurodegeneration. Since the disease course is uneven among patients, biomarkers are needed to provide insights into pathogenesis, diagnosis, and prognosis of events that affect neurons during this subclinical phase that shapes neurodegeneration and disability. Thus, subclinical cognitive decline must be better understood. One approach to this problem is to follow known biomarkers of neurodegeneration over time. These biomarkers include Neurofilament, Tau and phosphotau protein, amyloid-peptide-β, Brl2 and Brl2-23, N-Acetylaspartate, and 14-3-3 family proteins. A composite set of these serum-based biomarkers of neurodegeneration might provide a distinct signature in early vs. late subclinical cognitive decline, thus offering additional diagnostic criteria for progressive neurodegeneration and response to treatment. Studies on serum-based biomarkers are described together with selective studies on CSF-based biomarkers and MRI-based biomarkers.

Serum Neurofilament Light Chain in Wilson's Disease: A Promising Indicator but Unparallel to Real-Time Treatment Response

BACKGROUND

Wilson's disease (WD) currently lacks a promising indicator that could reflect neurological impairment and monitor treatment outcome. We aimed to investigate whether serum neurofilament light chain (sNfL) functions as a candidate for disease assessment and treatment monitoring of WD.

METHODS

We assessed preclinical and manifested WD patients' sNfL levels compared to controls and analyzed the differences between patients with various clinical symptoms. We then explored the correlation between clinical scales and sNfL levels. And repeated measurements were performed in 34 patients before and after treatment.

RESULTS

WD patients with neurological involvement had significantly higher sNfL levels than both hepatic patients and controls. Positive correlations were found between Unified Wilson's Disease Rating Scale scores and sNfL and between semiquantitative magnetic resonance imaging scales and sNfL levels in WD patients. However, in the treatment follow-up analysis, the trend of sNfL before and after treatment disaccorded with clinical response.

CONCLUSION

These findings suggest that sNfL levels can be an ideal indicator for the severity of neurological involvement but fail to evaluate change in disease condition after treatment. © 2022 International Parkinson and Movement Disorder Society.