Increased cerebrospinal fluid neurofilament light chain in central nervous system inflammatory demyelinating disease

Neurofilament heavy chain in secondary progressive multiple sclerosis

BACKGROUND

Biomarkers are needed to track progression in MS trials. Neurofilament heavy chain (NfH) has been underutilized due to assay limitations.

OBJECTIVE

To investigate the added value of cerebrospinal fluid (CSF) NfH in secondary progressive multiple sclerosis (SPMS) using contemporary immunoassays.

METHODS

This exploratory study was part of the MS-SMART trial. Clinical assessments (including expanded disability status scale, upper and lower limb function, visual acuity and symbol digit modalities test (SDMT)), CSF and serum sampling were acquired at baseline (n = 54), 48 and 96 weeks. Brain magnetic resonance imagings (MRIs) were obtained at baseline and 96 weeks. The NfL and NfH were measured using single-molecule array assay.

RESULTS

Baseline CSF NfH and NfL correlated with information processing speed at 96 weeks, with CSF NfH showing stronger correlations (r = -0.49 for SDMT) than CSF NfL (r = -0.37 for SDMT). Baseline CSF NfL predicted poorer hand dexterity at baseline, 48 and 96 weeks. CSF NfH was the only predictor of cortical grey matter at baseline, while baseline CSF NfL was the only predictor of brain atrophy at 96 weeks. Serum neurofilaments showed limited associations.

CONCLUSION

CSF neurofilaments are better outcomes than serum neurofilaments in small SPMS studies. CSF NfH and NfL variably predict worsening hand function, information processing speed and brain volume loss, possibly reflecting complementary aspects of neurodegeneration.

Multifaceted Biomarkers Suggest a Similar Profile of CNS Pathology in Relapsing and Progressive MS

BACKGROUND

Relapsing-remitting (RR) and primary progressive (PP) multiple sclerosis (MS) have distinct clinical courses, but underlying pathophysiological differences remain unclear. We compared pathological components between RRMS, PPMS, and other inflammatory and neurodegenerative disorders, leveraging soluble biomarkers and post-mortem pathology.

METHODS

Serum and cerebrospinal fluid (CSF) of people diagnosed with (pw) PPMS (n = 104), RRMS (n = 38), Alzheimer's disease (AD, n = 22), neuromyelitis optica spectrum disorder (NMOSD, n = 10), and myelin oligodendrocyte glycoprotein-associated disease (MOGAD, n = 10) were collected. B-cell maturation antigen (BCMA), soluble CD27 (sCD27), osteopontin (OPN), chitinase-3-like-1 (CHI3L1), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL) and synaptosomal-associated protein-25 (SNAP25) were measured. Lymphocytes (CD20+, CD138+, CD3+) and pyramidal-tract axonal density in RR-onset (n = 86) and PPMS (n = 45) post-mortem brain tissue were quantified.

RESULTS

Soluble and post-mortem tissue biomarkers did not differ between pwRRMS and pwPPMS. Compared to AD, MS had higher CSF sCD27 (p < 0.001) but lower serum CHI3L1 and GFAP, and CSF OPN and SNAP25 (all p < 0.05). Serum OPN was lower in RRMS than NMOSD (p = 0.013). Principal component analyses and K-means clustering showed substantial overlap of RRMS and PPMS biomarkers, distinct from AD. In all pwMS, serum NfL and CSF BCMA correlated with clinical/radiological disease activity, CSF BCMA and sCD27 with inflammatory parameters, and serum GFAP, CSF GFAP, and CSF NfL with Expanded Disability Status Scale (EDSS) score.

CONCLUSIONS

Serum and CSF soluble biomarker profiles and post-mortem pathology do not differentiate RRMS from PPMS diagnoses but reflect the extent of inflammation and tissue damage. Detailed assessment of MS-associated inflammation and tissue damage may enhance classification and therapeutic strategies.

Neurofilament light chain levels in neuronal surface antibody-associated autoimmune encephalitis: a systematic review and meta-analysis

BACKGROUND

Neuronal surface antibody-associated autoimmune encephalitis (NSAE) is a group of neuro-inflammatory disorders that is mediated by autoantibodies against the cell-surface and synaptic antigens. Studies have explored the role of neurofilament light chain (NfL) in NSAE and provided inconsistent data. We performed a systematic review and meta-analysis to evaluate the NfL levels in the serum and cerebrospinal fluid (CSF) of patients with NSAE.

METHODS

The National Center for Biotechnology Information (NCBI, PubMed), Web of Knowledge, and the Cochrane Library databases were searched for studies reporting NfL levels in patients with NSAE. Random-effects meta-analysis was used to pool results across studies.

RESULTS

Thirteen studies were included in the final systematic review and meta-analysis. The serum NfL levels were significantly higher in patients with NSAE compared to unaffected controls (standardized mean difference [SMD] = 0.909, 95% confidence interval [CI]: 0.536-1.282). Similarly, the CSF NfL levels were elevated in patients with NSAE (SMD = 0.897, 95% CI: 0.508-1.286). The serum and CSF NfL levels were not significantly correlated with disease severity, prognosis, and abnormalities in magnetic resonance imaging, electroencephalography, and CSF.

CONCLUSIONS

NfL levels in the serum and CSF were higher in patients with NSAE compared to unaffected controls. However, the NfL levels were not shown to be significantly associated with clinical or paraclinical features.

Biomarkers for neuromyelitis optica: a visual analysis of emerging research trends

Neuromyelitis optica is an inflammatory demyelinating disease of the central nervous system that differs from multiple sclerosis. Over the past 20 years, the search for biomarkers for neuromyelitis optica has been ongoing. Here, we used a bibliometric approach to analyze the main research focus in the field of biomarkers for neuromyelitis optica. Research in this area is consistently increasing, with China and the United States leading the way on the number of studies conducted. The Mayo Clinic is a highly reputable institution in the United States, and was identified as the most authoritative institution in this field. Furthermore, Professor Wingerchuk from the Mayo Clinic was the most authoritative expert in this field. Keyword analysis revealed that the terms "neuromyelitis optica" (261 times), "multiple sclerosis" (220 times), "neuromyelitis optica spectrum disorder" (132 times), "aquaporin 4" (99 times), and "optical neuritis" (87 times) were the most frequently used keywords in literature related to this field. Comprehensive analysis of the classical literature showed that the majority of publications provide conclusive research evidence supporting the use of aquaporin-4-IgG and neuromyelitis optica-IgG to effectively diagnose and differentiate neuromyelitis optica from multiple sclerosis. Furthermore, aquaporin-4-IgG has emerged as a highly specific diagnostic biomarker for neuromyelitis optica spectrum disorder. Myelin oligodendrocyte glycoprotein-IgG is a diagnostic biomarker for myelin oligodendrocyte glycoprotein antibody-associated disease. Recent biomarkers for neuromyelitis optica include cerebrospinal fluid immunological biomarkers such as glial fibrillary acidic protein, serum astrocyte damage biomarkers like FAM19A5, serum albumin, and gamma-aminobutyric acid. The latest prospective clinical trials are exploring the potential of these biomarkers. Preliminary results indicate that glial fibrillary acidic protein is emerging as a promising candidate biomarker for neuromyelitis optica spectrum disorder. The ultimate goal of future research is to identify non-invasive biomarkers with high sensitivity, specificity, and safety for the accurate diagnosis of neuromyelitis optica.

Cerebrospinal fluid neurofilament light chain levels in children with acquired demyelinating syndrome

Objective

To study the cerebrospinal fluid (CSF) neurofilament light chain (NfL) in pediatric acquired demyelinating syndrome (ADS) and its association with factors of laboratory and imaging results.

Methods

We analyzed clinical data from children with ADS collected from May 2020 to January 2021 at the Department of Neurology of Guangzhou Women and Children's Medical Center. Enzyme-linked immunosorbent assays were used to detect the CSF NfL of patients.

Results

Thirty pediatric ADS patients (17 male, 13 female) were included in the study. The most frequent diagnosis was uncategorized ADS (36.7%, 11/30), followed by acute disseminating encephalomyelitis (ADEM) (23.3%, 7/30), myelin oligodendrocyte glycoprotein antibody-associated disorder (MOGAD) (20.0%, 6/30), NMO (6.7%, 2/30), multiple sclerosis (MS) (6.7%, 2/30), and neuromyelitis optic spectrum disorders (NMOSD) (6.7%, 2/30). The median CSF NfL for the first time was 7,425.28 pg/ml (interquartile range, 1,273.51, >10,000 pg/ml). CSF NfL increase over normal value (<290.00 pg/ml for people younger than 30 years old) was seen in 98.7% of patients. Patients were divided into uncategorized ADS, ADEM, MOGAD, and MS/NMO/NMOSD groups, with no significant difference in CSF NfL between each group. The CSF NfL positively correlated with the immunoglobulin (Ig) G (ρ = 0.473) and IgE (ρ = 0.366). However, the CSF NfL did not correlate with CSF white blood count and CSF protein. Furthermore, there was no significant difference between patients with oligoclonal bands positive and without. The CSF NfL negatively correlated with interferon γ (ρ = -0.501), CD45 + CD3+ T (ρ = -0.466), CD45 + CD3 + CD4+ T (ρ = -0.466), and CD45 + CD3 + CD8+ T cells (ρ = -0.521). However, it did not correlate with CD45 + CD19+ B cells. CSF NfL in patients with cerebral white matter lesions in MRI was higher than in patients without. Moreover, the CSF NfL positively correlated with the number of brain MRI locations (ρ = 0.362). Nine patients underwent multiple detections of CSF NfL, and their CSF NfL for the last detection was not significantly different from the first.

Conclusions

The CSF NfL increases significantly in pediatric ADS, and it can be a biomarker of neuro-axonal injury and a good indication of the extent of lesions.

Neurofilaments in neurologic disease

Neurofilaments (NFs), major cytoskeletal constituents of neurons, have emerged as universal biomarkers of neuronal injury. Neuroaxonal damage underlies permanent disability in various neurological conditions. It is crucial to accurately quantify and longitudinally monitor this damage to evaluate disease progression, evaluate treatment effectiveness, contribute to novel treatment development, and offer prognostic insights. Neurofilaments show promise for this purpose, as their levels increase with neuroaxonal damage in both cerebrospinal fluid and blood, independent of specific causal pathways. New assays with high sensitivity allow reliable measurement of neurofilaments in body fluids and open avenues to investigate their role in neurological disorders. This book chapter will delve into the evolving landscape of neurofilaments, starting with their structure and cellular functions within neurons. It will then provide a comprehensive overview of their broad clinical value as biomarkers in diseases affecting the central or peripheral nervous system.

Blood-based inflammatory protein biomarker panel for the prediction of relapse and severity in patients with neuromyelitis optica spectrum disorder: A prospective cohort study

BACKGROUND

To date, most existing models for predicting neuromyelitis optica spectrum disorder (NMOSD) are based primarily on clinical characteristics. Blood-based NMOSD severity and prognostic predictive immune- and inflammation-related biomarkers are needed. We aimed to investigate the associations between plasma inflammatory biomarkers and relapse and attack severity in NMOSD.

METHODS

This two-step, single-center prospective cohort study included discovery and validation cohorts. We quantified 92 plasma inflammatory proteins by using Olink's proximity extension assay and identified differentially expressed proteins in the relapse group (relapse within 1 year of follow-up) and severe attack group. To define a new molecular prognostic model, we calculated the risk score of each patient based on the key protein signatures and validated the results in the validation cohort.

RESULTS

The relapse prediction model, including FGF-23, DNER, GDNF, and SLAMF1, predicted the 1-year relapse risk. The severe attack prediction model, including PD-L1 and MCP-2, predicted the severe clinical attack risk. Both the relapse and severe attack prediction models demonstrated good discriminative ability and high accuracy in the validation cohort.

CONCLUSIONS

Our discovered biomarker signature and prediction models may complement current clinical risk stratification approaches. These inflammatory biomarkers could contribute to the discovery of therapeutic interventions and prevent NMOSD progression.

Neurofilament light chain as a biomarker in neuromyelitis optica spectrum disorder: a comprehensive review and integrated analysis with glial fibrillary acidic protein

BACKGROUND

In the context of neuromyelitis optica spectrum disorder (NMOSD), there are several measures that serve as a biomarker. However, each of the methods has the intrinsic limitations. While neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) have emerged as an additional biomarker for NMOSD, a thorough investigation of their role remains incomplete. Our aim is to provide a comprehensive review of the current literature regarding NfL and GFAP as a biomarker and explore their potential utility in NMOSD.

METHODS

We performed a comprehensive search using PubMed and Google Scholar to identify peer-reviewed articles investigating NfL and GFAP as a biomarker in NMOSD.

RESULTS

Our search identified 13 relevant studies. NfL consistently showed promise in distinguishing NMOSD patients from healthy individuals, although it had limited specificity in distinguishing NMOSD from other demyelinating diseases. NfL offered certain advantages over GFAP, notably its ability to predict disability worsening during attacks. In contrast, GFAP provided valuable insight, particularly in distinguishing NMOSD from multiple sclerosis and identifying clinical relapses. In addition, GFAP showed predictive potential for future attacks. Some studies even suggested that NfL may serve as an indicator of treatment response in NMOSD.

CONCLUSIONS

NfL and GFAP hold promise as biomarkers for NMOSD, demonstrating their usefulness in distinguishing patients from healthy individuals, assessing disease severity, and possibly reflecting treatment response. However, it is important to recognize that NfL and GFAP may, at some point, have different roles.

From Recognition to Remedy: The Significance of Biomarkers in Neurodegenerative Disease Pathology

With the inexorable aging of the global populace, neurodegenerative diseases (NDs) like Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS) pose escalating challenges, which are underscored by their socioeconomic repercussions. A pivotal aspect in addressing these challenges lies in the elucidation and application of biomarkers for timely diagnosis, vigilant monitoring, and effective treatment modalities. This review delineates the quintessence of biomarkers in the realm of NDs, elucidating various classifications and their indispensable roles. Particularly, the quest for novel biomarkers in AD, transcending traditional markers in PD, and the frontier of biomarker research in ALS are scrutinized. Emergent susceptibility and trait markers herald a new era of personalized medicine, promising enhanced treatment initiation especially in cases of SOD1-ALS. The discourse extends to diagnostic and state markers, revolutionizing early detection and monitoring, alongside progression markers that unveil the trajectory of NDs, propelling forward the potential for tailored interventions. The synergy between burgeoning technologies and innovative techniques like -omics, histologic assessments, and imaging is spotlighted, underscoring their pivotal roles in biomarker discovery. Reflecting on the progress hitherto, the review underscores the exigent need for multidisciplinary collaborations to surmount the challenges ahead, accelerate biomarker discovery, and herald a new epoch of understanding and managing NDs. Through a panoramic lens, this article endeavors to provide a comprehensive insight into the burgeoning field of biomarkers in NDs, spotlighting the promise they hold in transforming the diagnostic landscape, enhancing disease management, and illuminating the pathway toward efficacious therapeutic interventions.

Serum neurofilament and glial fibrillary acidic protein in idiopathic and seropositive transverse myelitis

BACKGROUND

Serum levels of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) reflect the disease activity and disability in central nervous system (CNS) demyelinating diseases. However, the clinical significance of NfL and GFAP in idiopathic transverse myelitis (iTM), an inflammatory spinal cord disease with unknown underlying causes, remains unclear. This study aimed to investigate NfL and GFAP levels in iTM and their association with the clinical parameters compared with those in TM with disease-specific antibodies such as anti-aquaporin 4 or myelin oligodendrocyte glycoprotein antibodies (sTM).

METHODS

We collected serum and clinical data of 365 patients with CNS inflammatory diseases from 12 hospitals. The serum NfL and GFAP levels were measured in patients with iTM (n = 37) and sTM (n = 39) using ultrasensitive single-molecule array assays. Regression analysis was performed to investigate the associations between serum levels of NfL and GFAP and the clinical parameters such as higher EDSS scores (EDSS ≥ 4.0).

RESULTS

Mean NfL levels were not significantly different between iTM (50.29 pg/ml) and sTM (63.18 pg/ml) (p = 0.824). GFAP levels were significantly lower in iTM (112.34 pg/ml) than in sTM (3814.20 pg/ml) (p = 0.006). NfL levels correlated with expanded disability status scale (EDSS) scores in sTM (p = 0.001) but not in iTM (p = 0.824). Disease duration also correlated with higher EDSS scores in sTM (p = 0.017).

CONCLUSION

NfL levels and disease duration correlated with EDSS scores in sTM, and GFAP levels could be a promising biomarker to differentiate iTM from sTM.

Serum levels of neurofilament light chains in pediatric multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Multiple sclerosis is a neuro-inflammatory disease that affects adults and children and causes somatic and cognitive symptoms. Diagnosis after the first clinical symptoms is challenging, involves laboratory and magnetic resonance imaging work-up and is often inconclusive unless subsequent clinical attacks occur. Neurofilament light chains are structural proteins within neurons. Levels of this marker in cerebrospinal fluid, plasma and serum are consistently higher in patients with an initial clinical demyelinating attack that later go on to develop multiple sclerosis. Evidence concerning serum levels of this biomarker in children with multiple sclerosis is scarce. Our aim is to review and analyze the evidence available for patients with multiple sclerosis, under the age of 18.

METHODS

We conducted a systematic search of PubMed/Medline, Embase, Cochrane Database, and ProQuest. Human studies that provided data on serum levels of Neurofilament light chains in pediatric patients with MS, measured at the time of the first demyelinating attack and before treatment were included in meta-analysis.

RESULTS

Three studies satisfied the inclusion criteria. 157 pediatric patients with multiple sclerosis and 270 hospital-based controls that did not present with this condition were included in the analysis. A fixed effects meta-analysis showed that the standardized mean difference between patients and controls is 1.82, with a 95% confidence interval of [1.56-2.08].

CONCLUSION

Pediatric patients with multiple sclerosis show higher levels of serum neurofilament light chains at their first clinical demyelinating attack compared to pediatric hospital-based controls.

Neurofilament light chain marks severity of papilledema in idiopathic intracranial hypertension

BACKGROUND

Neurofilament light chain (NfL) reflects axonal damage in neurological disorders. It has recently been evaluated in idiopathic intracranial hypertension (IIH). A biomarker indicating the severity of optic nerve damage in IIH could support diagnostic accuracy and therapeutic decisions.

METHODS

We retrospectively reviewed NfL concentrations in the cerebrospinal fluid (CSF) of 35 IIH patients and 12 healthy controls, who had received diagnostic workup for IIH in our clinic. The diagnosis of IIH was made according to the modified Friedman criteria for IIH and for IIH without papilledema Friedman DI et al Neurol 81:1159-1165 (2013) [1]. NfL in the CSF (CSF-NfL) was correlated with the severity of papilledema and with CSF opening pressure.

RESULTS

CSF-NfL correlated with CSF opening pressure at the time of collection. In patients with IIH and moderate or severe papilledema, CSF-NfL was significantly increased compared to patients with mild or no papilledema. Healthy controls with raised intracranial pressure showed no relevant elevation of CSF-NfL.

CONCLUSION

CSF-NfL appears to correlate with the severity of papilledema in IIH and with CSF opening pressure and may therefore be a predictor of optic nerve damage in IIH patients.

Protein biomarkers in multiple sclerosis

This review aimed to elucidate protein biomarkers in body fluids, such as blood and cerebrospinal fluid (CSF), to identify those that may be used for early diagnosis of multiple sclerosis (MS), prediction of disease activity, and monitoring of treatment response among MS patients. The potential biomarkers elucidated in this review include neurofilament proteins (NFs), glial fibrillary acidic protein (GFAP), leptin, brain-derived neurotrophic factor (BDNF), chitinase-3-like protein 1 (CHI3L1), C-X-C motif chemokine 13 (CXCL13), and osteopontin (OPN), with each biomarker playing a different role in MS. GFAP, leptin, and CHI3L1 levels were increased in MS patient groups compared to the control group. NFs are the most studied proteins in the MS field, and significant correlations with disease activity, future progression, and treatment outcomes are evident. GFAP CSF level shows a different pattern by MS subtype. Increased concentration of CHI3L1 in the blood/CSF of clinically isolated syndrome (CIS) is an independent predictive factor of conversion to definite MS. BDNF may be affected by chronic progression of MS. CHI3L1 has potential as a biomarker for early diagnosis of MS and prediction of disability progression, while CXCL13 has potential as a biomarker of prognosis of CIS and reflects MS disease activity. OPN was an indicator of disease severity. A periodic detailed patient evaluation should be performed for MS patients, and broadly and easily accessible biomarkers with higher sensitivity and specificity in clinical settings should be identified.

Novel CSF Biomarkers Tracking Autoimmune Inflammatory and Neurodegenerative Aspects of CNS Diseases

The accurate diagnosis of neuroinflammatory (NIDs) and neurodegenerative (NDDs) diseases and the stratification of patients into disease subgroups with distinct disease-related characteristics that reflect the underlying pathology represents an unmet clinical need that is of particular interest in the era of emerging disease-modifying therapies (DMT). Proper patient selection for clinical trials and identifying those in the prodromal stages of the diseases or those at high risk will pave the way for precision medicine approaches and halt neuroinflammation and/or neurodegeneration in early stages where this is possible. Towards this direction, novel cerebrospinal fluid (CSF) biomarker candidates were developed to reflect the diseased organ's pathology better. Μisfolded protein accumulation, microglial activation, synaptic dysfunction, and finally, neuronal death are some of the pathophysiological aspects captured by these biomarkers to support proper diagnosis and screening. We also describe advances in the field of molecular biomarkers, including miRNAs and extracellular nucleic acids known as cell-free DNA and mitochondrial DNA molecules. Here we review the most important of these novel CSF biomarkers of NIDs and NDDs, focusing on their involvement in disease development and emphasizing their ability to define homogeneous disease phenotypes and track potential treatment outcomes that can be mirrored in the CSF compartment.

Emerging Biomarkers of Multiple Sclerosis in the Blood and the CSF: A Focus on Neurofilaments and Therapeutic Considerations

INTRODUCTION

Multiple Sclerosis (MS) is the most common immune-mediated chronic neurodegenerative disease of the central nervous system (CNS) affecting young people. This is due to the permanent disability, cognitive impairment, and the enormous detrimental impact MS can exert on a patient's health-related quality of life. It is of great importance to recognise it in time and commence adequate treatment at an early stage. The currently used disease-modifying therapies (DMT) aim to reduce disease activity and thus halt disability development, which in current clinical practice are monitored by clinical and imaging parameters but not by biomarkers found in blood and/or the cerebrospinal fluid (CSF). Both clinical and radiological measures routinely used to monitor disease activity lack information on the fundamental pathophysiological features and mechanisms of MS. Furthermore, they lag behind the disease process itself. By the time a clinical relapse becomes evident or a new lesion appears on the MRI scan, potentially irreversible damage has already occurred in the CNS. In recent years, several biomarkers that previously have been linked to other neurological and immunological diseases have received increased attention in MS. Additionally, other novel, potential biomarkers with prognostic and diagnostic properties have been detected in the CSF and blood of MS patients.

AREAS COVERED

In this review, we summarise the most up-to-date knowledge and research conducted on the already known and most promising new biomarker candidates found in the CSF and blood of MS patients.

DISCUSSION

the current diagnostic criteria of MS relies on three pillars: MRI imaging, clinical events, and the presence of oligoclonal bands in the CSF (which was reinstated into the diagnostic criteria by the most recent revision). Even though the most recent McDonald criteria made the diagnosis of MS faster than the prior iteration, it is still not an infallible diagnostic toolset, especially at the very early stage of the clinically isolated syndrome. Together with the gold standard MRI and clinical measures, ancillary blood and CSF biomarkers may not just improve diagnostic accuracy and speed but very well may become agents to monitor therapeutic efficacy and make even more personalised treatment in MS a reality in the near future. The major disadvantage of these biomarkers in the past has been the need to obtain CSF to measure them. However, the recent advances in extremely sensitive immunoassays made their measurement possible from peripheral blood even when present only in minuscule concentrations. This should mark the beginning of a new biomarker research and utilisation era in MS.

Risk factors for idiopathic myelitis at admission and predictors for late diagnostic change

Immune-mediated myelopathy (IMM) diagnosis is challenging, and its etiology may remain unclear despite extensive investigation. We evaluated diagnostic changes in IMM patients during follow-up. We included 80 patients, 61.3% female, with median follow-up time 62.5 months. Diagnoses at discharge were: 48.8% Multiple Sclerosis-IMM (MS-IMM), 32.5% I-IMM, 11.3% Neuromyelitis Optica Spectrum Disorders-IMM (NMOSD-IMM), 1.3% MOG encephalomyelitis (MOGAD), and 6.2% Others IMM (O-IMM). Twenty-two  patients (27.5%) changed diagnosis (median 15.5  months): 68.8% MS-IMM, 12.5%  NMOSD-IMM, 3.8% MOGAD, 10.0% I-IMM, and 5.0% O-IMM. Most patients that changed diagnosis were I-IMM. Predictive factors for diagnostic change in I-IMM were: autonomous gait (p = 0.029), lesions suggestive of MS (p = 0.039), higher number of lesions (p = 0.043), lesions length < 3 vertebral bodies (p = 0.033), cervical involvement (p = 0.038), and lower EDSS at admission (p = 0.013). Etiologic reclassifications in IMM are common, therefore patients require an appropriate follow-up time to increase diagnostic accuracy.

A Longitudinal, Observational Analysis of Neuronal Injury Biomarkers in a Case Report of a Patient With Paraneoplastic Anti-CRMP5 Antibody-Associated Transverse Myelitis

Biomarkers are needed to guide therapeutic decision making in autoimmune and paraneoplastic neurologic disorders. Here, we describe a case of paraneoplastic collapsing response-mediator protein-5 (CRMP5)-associated transverse myelitis (TM) where plasma neurofilament light (NfL) chain and glial fibrillary protein (GFAP) levels were observed over a 14-month clinical course, correlating with radiographical and clinical outcome measures in response to treatment. Blood and CSF samples obtained at diagnosis as well as 7 and 14 months into treatment. At the time of initial diagnosis, both plasma NfL (782.62 pg/ml) and GFAP (283.26 pg/ml) were significantly elevated. Initial treatment was with IV steroids and plasma exchange (PLEX) followed by neuroendocrine tumor removal, chemotherapy, and radiation. After initial improvement with chemotherapy, the patient experienced clinical worsening and transient elevation of plasma NfL (103.27 pg/ml and GFAP (211.58 pg/ml) levels. Whole body positron emission tomography PET scan did not demonstrate recurrence of malignancy. Repeat PLEX and rituximab induction resulted in improvements in patient function, neurologic exam, and plasma biomarker levels. To our knowledge, this is the first described longitudinal, prospective analysis of neuronal injury biomarkers and association of clinical treatment outcomes in CRMP5 myelitis. Our findings suggest that clinical improvement correlates with NfL and GFAP concentrations.

The potential of serum neurofilament as biomarker for multiple sclerosis

Multiple sclerosis is a highly heterogeneous disease, and the detection of neuroaxonal damage as well as its quantification is a critical step for patients. Blood-based serum neurofilament light chain (sNfL) is currently under close investigation as an easily accessible biomarker of prognosis and treatment response in patients with multiple sclerosis. There is abundant evidence that sNfL levels reflect ongoing inflammatory-driven neuroaxonal damage (e.g. relapses or MRI disease activity) and that sNfL levels predict disease activity over the next few years. In contrast, the association of sNfL with long-term clinical outcomes or its ability to reflect slow, diffuse neurodegenerative damage in multiple sclerosis is less clear. However, early results from real-world cohorts and clinical trials using sNfL as a marker of treatment response in multiple sclerosis are encouraging. Importantly, clinical algorithms should now be developed that incorporate the routine use of sNfL to guide individualized clinical decision-making in people with multiple sclerosis, together with additional fluid biomarkers and clinical and MRI measures. Here, we propose specific clinical scenarios where implementing sNfL measures may be of utility, including, among others: initial diagnosis, first treatment choice, surveillance of subclinical disease activity and guidance of therapy selection.

Autopsy-diagnosed neurodegenerative dementia cases support the use of cerebrospinal fluid protein biomarkers in the diagnostic work-up

Various proteins play a decisive role in the pathology of different neurodegenerative diseases. Nonetheless, most of these proteins can only be detected during a neuropathological assessment, although some non-specific biomarkers are routinely tested for in the cerebrospinal fluid (CSF) as a part of the differential diagnosis of dementia. In antemortem CSF samples from 117 patients with different types of neuropathologically confirmed neurodegenerative disease with dementia, we assessed total-tau (t-tau), phosphorylated-tau (181P) (p-tau), amyloid-beta (1–42) (Aβ42), TAR DNA binding protein (TDP)-43, progranulin (PGRN), and neurofilament light (NfL) chain levels, and positivity of protein 14-3-3. We found t-tau levels and the t-tau/p-tau ratios were significantly higher in prion diseases compared to the other neurodegenerative diseases. Statistically significant differences in the t-tau/Aβ42 ratio predominantly corresponded to t-tau levels in prion diseases and Aβ42 levels in AD. TDP-43 levels were significantly lower in prion diseases. Additionally, the TDP-43/Aβ42 ratio was better able to distinguish Alzheimer’s disease from other neurodegenerative diseases compared to using Aβ42 alone. In frontotemporal lobar degeneration, PRGN levels were significantly higher in comparison to other neurodegenerative diseases. There is an increasing need for biomarkers suitable for diagnostic workups for neurodegenerative diseases. It appears that adding TDP-43 and PGRN to the testing panel for neurodegenerative diseases could improve the resolution of differential diagnoses.

The Evolution of Neurofilament Light Chain in Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune, inflammatory neurodegenerative disease of the central nervous system characterized by demyelination and axonal damage. Diagnosis and prognosis are mainly assessed through clinical examination and neuroimaging. However, more sensitive biomarkers are needed to measure disease activity and guide treatment decisions in MS. Prompt and individualized management can reduce inflammatory activity and delay disease progression. Neurofilament Light chain (NfL), a neuron-specific cytoskeletal protein that is released into the extracellular fluid following axonal injury, has been identified as a biomarker of disease activity in MS. Measurement of NfL levels can capture the extent of neuroaxonal damage, especially in early stages of the disease. A growing body of evidence has shown that NfL in cerebrospinal fluid (CSF) and serum can be used as reliable indicators of prognosis and treatment response. More recently, NfL has been shown to facilitate individualized treatment decisions for individuals with MS. In this review, we discuss the characteristics that make NfL a highly informative biomarker and depict the available technologies used for its measurement. We further discuss the growing role of serum and CSF NfL in MS research and clinical settings. Finally, we address some of the current topics of debate regarding the use of NfL in clinical practice and examine the possible directions that this biomarker may take in the future.

Risk of relapse in patients with neuromyelitis optica spectrum disorder: Recognition and preventive strategy

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune inflammatory disorder of the central nervous system (CNS) that is mainly associated with serum autoantibodies against aquaporin-4 (AQP4) in astrocytes. The relapsing clinical course of NMOSD, which can be blinding and disabling due to severe visual impairment, spinal cord lesions and a group of brain syndromes, suggests the importance of accurately evaluating the likelihood and severity of relapse at an early stage of the disease. To date, many risk factors have been revealed in association with relapse, and only some of them are supported by substantial evidence. Furthermore, while the clinical use of conventional immunosuppressants is mostly empirical, an increasing number of emerging therapies for monoclonal antibodies have been confirmed by several randomized placebo-controlled trials to be effective and safe for relapse prevention. In this review, we summarize the reported risk factors that may influence the frequency, symptoms, severity and prognosis of relapse in NMOSD, as well as the efficacy and safety of emerging therapies for relapse prevention. All of these results enable us to better recognize patients who are at higher risk of relapse and suggest more effective monoclonal antibody therapies for use in these patients.

Serum neurofilament light chain in FTLD: association with C9orf72, clinical phenotype, and prognosis

Objective

The aim of the present study was to compare the levels of serum neurofilament light chain (sNfL) in frontotemporal lobar degeneration (FTLD) patients of different clinical subtypes (bvFTD, PPA, and FTLD‐MND) and with or without the C9orf72 repeat expansion, and to correlate sNfL levels to disease progression, assessed by the brain atrophy rate and survival time.

Methods

The sNfL levels were determined from 78 FTLD patients (C9orf72 repeat expansion carriers [n = 26] and non‐carriers [n = 52]) with Single Molecule Array (SIMOA). The progression of brain atrophy was evaluated using repeated T1‐weighted MRI scans and the survival time from medical records.

Results

In the total FTLD cohort, sNfL levels were significantly higher in C9orf72 repeat expansion carriers compared to non‐carriers. Considering clinical phenotypes, sNfL levels were higher in the C9orf72 repeat expansion carriers than in the non‐carriers in bvFTD and PPA groups. Furthermore, sNfL levels were the highest in the FTLD‐MND group (median 105 pg/mL) and the lowest in the bvFTD group (median 27 pg/mL). Higher sNfL levels significantly correlated with frontal cortical atrophy rate and subcortical grey matter atrophy rate. The higher sNfL levels also associated with shorter survival time.

Interpretation

Our results indicate that the C9orf72 repeat expansion carriers show elevated sNFL levels compared to non‐carriers and that the levels differ among different clinical phenotypes of FTLD. Higher sNfL levels correlated with a shorter survival time and cortical and subcortical atrophy rates. Thus, sNfL could prove as a potential prognostic biomarker in FTLD.

MRI features associated with rapid disease activity in clinically isolated syndrome patients at high risk for multiple sclerosis

Clinically isolated syndrome (CIS) is a central nervous system inflammatory and demyelinating event that lasts at least 24 h and can represent the first episode of relapsing-remitting multiple sclerosis. MRI is an important imaging tool in the diagnosis and longitudinal monitoring of CIS progression. Accurate differential diagnosis of high-risk versus low-risk CIS is important because high-risk CIS patients could be treated early. Although a few studies have previously characterized CIS and explored possible imaging predictors of CIS conversion to MS, it remains unclear which amongst the commonly measured MRI features, if any, are good predictors of rapid disease progression in CIS patients. The goal of this review paper is to identify MRI features in high-risk CIS patients that are associated with rapid disease activity within 5 years as measured by clinical disability.

Increased CSF Soluble TREM2 Concentration in Patients With Neurosyphilis

Objective: To explore cerebrospinal fluid (CSF) levels of soluble triggering receptor expressed on myeloid cells 2 (sTREM2) and neurofilament light proteins (NFL) in patients with neurosyphilis (NS).

Methods: We enrolled 71 NS patients (41 early-NS and 30 late-NS patients) and 20 syphilis but non-NS patients whose CSF samples were collected. The CSF levels of the microglial activation biomarker sTREM2 and neuronal injury biomarker NFL were measured using ELISA.

Results: CSF sTREM2 levels were significantly higher in NS patients compared to those in syphilis/non-NS patients (p < 0.001). In a subgroup analysis, the CSF sTREM2 levels elevated significantly in late-NS patients than those in early-NS patients (p < 0.001). The CSF sTREM2 levels in early-NS group were also significantly higher than those in syphilis/non-NS group (p = 0.024). Like CSF sTREM2, similar differences between groups were also found in CSF NFL. There was a moderate correlation between CSF sTREM2 and CSF NFL (r = 0.406, p < 0.001) in NS group.

Conclusions: CSF sTREM2 levels elevated in NS and peaked at the late stage, suggesting that CSF sTREM2 may be a useful marker to quantify microglia activation in NS and may play a role in the progression of NS. The positive correlation between CSF sTREM2 and CSF NFL indicates a linkage between microglial activation and neuronal injury in NS.

Neurofilaments: The C-Reactive Protein of Neurology

Neurofilaments (NFs) are quickly becoming the biomarkers of choice in the field of neurology, suggesting their use as an unspecific screening marker, much like the use of elevated plasma C-reactive protein (CRP) in other fields. With sensitive techniques being readily available, evidence is growing regarding the diagnostic and prognostic value of NFs in many neurological disorders. Here, we review the latest literature on the structure and function of NFs and report the strengths and pitfalls of NFs as markers of neurodegeneration in the context of neurological diseases of the central and peripheral nervous systems.