Vitamin D did not reduce multiple sclerosis disease activity after a clinically isolated syndrome.

Low serum levels of 25-hydroxyvitamin D [25(OH)D] and low sunlight exposure are known risk factors for the development of multiple sclerosis. Add-on vitamin D supplementation trials in established multiple sclerosis have been inconclusive. The effects of vitamin D supplementation to prevent multiple sclerosis is unknown. We aimed to test the hypothesis that oral vitamin D3 supplementation in high-risk clinically isolated syndrome (abnormal MRI, at least three T2 brain and/or spinal cord lesions), delays time to conversion to definite multiple sclerosis, that the therapeutic effect is dose-dependent, and that all doses are safe and well tolerated. We conducted a double-blind trial in Australia and New Zealand. Eligible participants were randomized 1:1:1:1 to placebo, 1000, 5000 or 10 000 international units (IU) of oral vitamin D3 daily within each study centre (n = 23) and followed for up to 48 weeks. Between 2013 and 2021, we enrolled 204 participants. Brain MRI scans were performed at baseline, 24 and 48 weeks. The main study outcome was conversion to clinically definite multiple sclerosis based on the 2010 McDonald criteria defined as either a clinical relapse or new brain MRI T2 lesion development. We included 199 cases in the intention-to-treat analysis based on assigned dose. Of these, 116 converted to multiple sclerosis by 48 weeks (58%). Compared to placebo, the hazard ratios (95% confidence interval) for conversion were 1000 IU 0.87 (0.50, 1.50); 5000 IU 1.37 (0.82, 2.29); and 10 000 IU 1.28 (0.76, 2.14). In an adjusted model including age, sex, latitude, study centre and baseline symptom number, clinically isolated syndrome onset site, presence of infratentorial lesions and use of steroids, the hazard ratios (versus placebo) were 1000 IU 0.80 (0.45, 1.44); 5000 IU 1.36 (0.78, 2.38); and 10 000 IU 1.07 (0.62, 1.85). Vitamin D3 supplementation was safe and well tolerated. We did not demonstrate reduction in multiple sclerosis disease activity by vitamin D3 supplementation after a high-risk clinically isolated syndrome.

CLADIN- CLADribine and INnate immune response in multiple sclerosis - A phase IV prospective study.

Cladribine (Mavenclad®) is an oral treatment for relapsing remitting MS (RRMS), but its mechanism of action and its effects on innate immune responses in unknown. This study is a prospective Phase IV study of 41 patients with RRMS, and aims to investigate the mechanism of action of cladribine on peripheral monocytes, and its impact on the P2X7 receptor. There was a significant reduction in monocyte count in vivo at week 1 post cladribine administration, and the subset of cells being most impacted were the CD14lo CD16+ 'non-classical' monocytes. Of the 14 cytokines measured in serum, CCL2 levels increased at week 1. In vitro, cladrabine induced a reduction in P2X7R pore as well as channel activity. This study demonstrates a novel mechanism of action for cladribine. It calls for studying potential benefits of cladribine in progressive forms of MS and other neurodegenerative diseases where innate immune related inflammation is implicated in disease pathogenesis.

Methodological considerations for observational studies of treatment effectiveness in neurology: a clinician's guide.

Data from cohorts, registries, randomised trials, electronic medical records and administrative claims databases have increasingly been used to inform the use of therapies for neurological diseases. While novel sophisticated methods are enabling us to use existing data to guide treatment decisions, the complexity of statistical methodology is making appraisal of clinical evidence increasingly demanding. In this narrative review, we provide a brief overview of the most commonly used methods for evaluation of treatment effectiveness in neurology. This primer discusses complementarity of randomised and non-randomised study designs, sources of observational data, different forms of bias and the appropriate mitigation strategies, statistical significance, Bayesian approaches and provides an overview of multivariable regression models, propensity score-based models, causal inference, mediation analysis and Mendelian randomisation.

Oral corticosteroid dosage and taper duration at onset in myelin oligodendrocyte glycoprotein antibody-associated disease influences time to first relapse.

BACKGROUND: We sought to identify an optimal oral corticosteroid regimen at the onset of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), which would delay time to first relapse while minimising cumulative corticosteroid exposure. METHODS: In a retrospective multicentre cohort study, Cox proportional hazards models examined the relationship between corticosteroid course as a time-varying covariate and time to first relapse. Simon-Makuch and Kaplan-Meier plots identified an optimal dosing strategy. RESULTS: We evaluated 109 patients (62 female, 57%; 41 paediatric, 38%; median age at onset 26 years, (IQR 8-38); median follow-up 6.2 years (IQR 2.6-9.6)). 76/109 (70%) experienced a relapse (median time to first relapse 13.7 months; 95% CI 8.2 to 37.9). In a multivariable model, higher doses of oral prednisone delayed time to first relapse with an effect estimate of 3.7% (95% CI 0.8% to 6.6%; p=0.014) reduced hazard of relapse for every 1 mg/day dose increment. There was evidence of reduced hazard of relapse for patients dosed ≥12.5 mg/day (HR 0.21, 95% CI 0.07 to 0.6; p=0.0036), corresponding to a 79% reduction in relapse risk. There was evidence of reduced hazard of relapse for those dosed ≥12.5 mg/day for at least 3 months (HR 0.12, 95% CI 0.03 to 0.44; p=0.0012), corresponding to an 88% reduction in relapse risk compared with those never treated in this range. No patient with this recommended dosing at onset experienced a Common Terminology Criteria for Adverse Events grade >3 adverse effect. CONCLUSIONS: The optimal dose of 12.5 mg of prednisone daily in adults (0.16 mg/kg/day for children) for a minimum of 3 months at the onset of MOGAD delays time to first relapse.

Emulating randomised clinical trials in relapsing-remitting multiple sclerosis with non-randomised real-world evidence: an application using data from the MSBase Registry.

BACKGROUND: To mimic as closely as possible a randomised controlled trial (RCT) and calibrate the real-world evidence (RWE) studies against a known treatment effect would be helpful to understand if RWE can support causal conclusions in selected circumstances. The aim was to emulate the TRANSFORMS trial comparing Fingolimod (FTY) versus intramuscular interferon ß-1a (IFN) using observational data. METHODS: We extracted from the MSBase registry all the patients with relapsing-remitting multiple sclerosis (RRMS) collected in the period 2011-2021 who received IFN or FTY (0.5 mg) and with the same inclusion and exclusion criteria of the TRANSFORMS RCT. The primary endpoint was the annualised relapse rate (ARR) over 12 months. Patients were 1:1 propensity-score (PS) matched. Relapse-rate ratio (RR) was calculated by mean of a negative binomial regression. RESULTS: A total of 4376 patients with RRMS (1140 in IFN and 3236 in FTY) were selected. After PS, 856 patients in each group were matched. The ARR was 0.45 in IFN and 0.25 in FTY with a significant difference between the two groups (RR: 0.55, 95% CI: 0.45 to 0.68; p<0.001). The result of the emulation was very similar and fell within the 95% CI of that observed in the RCT (RR: 0.49, 95% CI: 0.37 to 0.64; p<0.001) with a standardised difference of 0.66 (p=0.51). CONCLUSIONS: By applying the same inclusion and exclusion criteria used in the RCT and employing appropriate methodology, we successfully replicated the RCT results with only minor discrepancies. Also, even if the confounding bias cannot be fully eliminated, conducting a rigorous target trial emulation could still yield valuable insights for comparative effectiveness research.

Comparing ocrelizumab to interferon/glatiramer acetate in people with multiple sclerosis over age 60.

BACKGROUND: Ongoing controversy exists regarding optimal management of disease modifying therapy (DMT) in older people with multiple sclerosis (pwMS). There is concern that the lower relapse rate, combined with a higher risk of DMT-related infections and side effects, may alter the risk-benefit balance in older pwMS. Given the lack of pwMS above age 60 in randomised controlled trials, the comparative efficacy of high-efficacy DMTs such as ocrelizumab has not been shown in older pwMS. We aimed to evaluate the comparative effectiveness of ocrelizumab, a high-efficacy DMT, versus interferon/glatiramer acetate (IFN/GA) in pwMS over the age of 60. METHODS: Using data from MSBase registry, this multicentre cohort study included pwMS above 60 who switched to or started on ocrelizumab or IFN/GA. We analysed relapse and disability outcomes after balancing covariates using an inverse probability treatment weighting (IPTW) method. Propensity scores were obtained based on age, country, disease duration, sex, baseline Expanded Disability Status Scale, prior relapses (all-time, 12 months and 24 months) and prior DMT exposure (overall number and high-efficacy DMTs). After weighting, all covariates were balanced. Primary outcomes were time to first relapse and annualised relapse rate (ARR). Secondary outcomes were 6-month confirmed disability progression (CDP) and confirmed disability improvement (CDI). RESULTS: A total of 248 participants received ocrelizumab, while 427 received IFN/GA. The IPTW-weighted ARR for ocrelizumab was 0.01 and 0.08 for IFN/GA. The IPTW-weighted ARR ratio was 0.15 (95% CI 0.06 to 0.33, p<0.001) for ocrelizumab compared with IFN/GA. On IPTW-weighted Cox regression models, HR for time to first relapse was 0.13 (95% CI 0.05 to 0.26, p<0.001). The hazard of first relapse was significantly reduced in ocrelizumab users after 5 months compared with IFN/GA users. However, the two groups did not differ in CDP or CDI over 3.57 years. CONCLUSION: In older pwMS, ocrelizumab effectively reduced relapses compared with IFN/GA. Overall relapse activity was low. This study adds valuable real-world data for informed DMT decision making with older pwMS. Our study also confirms that there is a treatment benefit in older people with MS, given the existence of a clear differential treatment effect between ocrelizumab and IFN/GA in the over 60 age group.

Effectiveness of autologous haematopoietic stem cell transplantation versus natalizumab in progressive multiple sclerosis.

BACKGROUND: Natalizumab was not shown to modify disability in progressive multiple sclerosis (MS). This matched observational study compared the effectiveness of autologous haematopoietic stem cell transplantation (AHSCT) with natalizumab in progressive MS. METHODS: Patients with primary/secondary progressive MS from seven AHSCT MS centres and the MSBase registry, treated with AHSCT or natalizumab, were matched on a propensity score derived from sex, age, Expanded Disability Status Scale (EDSS), number of relapses 12/24 months before baseline, time from MS onset, the most effective prior therapy and country. The pairwise-censored groups were compared on hazards of 6-month confirmed EDSS worsening and improvement, relapses and annualised relapse rates (ARRs), using Andersen-Gill proportional hazards models and conditional negative binomial model. RESULTS: 39 patients treated with AHSCT (37 with secondary progressive MS, mean age 37 years, EDSS 5.7, 28% with recent disability progression, ARR 0.54 during the preceding year) were matched with 65 patients treated with natalizumab. The study found no evidence for difference in hazards of confirmed EDSS worsening (HR 1.49, 95% CI 0.70 to 3.14) and improvement (HR 1.50, 95% CI 0.22 to 10.29) between AHSCT and natalizumab over up to 4 years. The relapse activity was also similar while treated with AHSCT and natalizumab (ARR: mean±SD 0.08±0.28 vs 0.08±0.25; HR 1.05, 95% CI 0.39 to 2.82). In the AHSCT group, 3 patients experienced febrile neutropenia during mobilisation, 9 patients experienced serum sickness, 6 patients required intensive care unit admission and 36 patients experienced complications after discharge. No treatment-related deaths were reported. CONCLUSION: This study does not support the use of AHSCT to control disability in progressive MS with advanced disability and low relapse activity.

Predictors of relapse risk and treatment response in AQP4-IgG positive and seronegative NMOSD: A multicentre study.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) can be categorised into aquaporin-4 antibody (AQP4-IgG) NMOSD or seronegative NMOSD. While our knowledge of AQP4-IgG NMOSD has evolved significantly in the past decade, seronegative NMOSD remains less understood. This study aimed to evaluate the predictors of relapses and treatment responses in AQP4-IgG NMOSD and seronegative NMOSD. METHODS: This was a multicentre, international, retrospective cohort study using the MSBase registry. Recurrent relapse risk was assessed using an Andersen-Gill model and risk of first relapse was evaluated using a Cox proportional hazards model. Covariates that putatively influence relapse risk included demographic factors, clinical characteristics and immunosuppressive therapies; the latter was assessed as a time-varying covariate. RESULTS: A total of 398 patients (246 AQP4-IgG NMOSD and 152 seronegative NMOSD) were included. The AQP4-IgG NMOSD and seronegative NMOSD patients did not significantly differ by age at disease onset, ethnicity or annualised relapse rate. Both low-efficacy and high-efficacy immunosuppressive therapies were associated with significant reductions in recurrent relapse risk, with notably greater protection conferred by high-efficacy therapies in both AQP4-IgG NMOSD (HR 0.27, 95% CI 0.15 to 0.49, p<0.001) and seronegative NMOSD (HR 0.21, 95% CI 0.08 to 0.51, p<0.001). Longer disease duration (HR 0.97, 95% CI 0.95 to 0.99, p<0.001) and male sex (HR 0.52, 95% CI 0.34 to 0.84, p=0.007) were additional protective variables in reducing the recurrent relapse risk for the AQP4-IgG NMOSD group. CONCLUSION: Although further studies are needed to improve our understanding of seronegative NMOSD, our findings underscore the importance of aggressive treatment with high-efficacy immunotherapies in both NMOSD subtypes, regardless of serostatus.

The MOG antibody non-P42 epitope is predictive of a relapsing course in MOG antibody-associated disease.

BACKGROUND: Myelin oligodendrocyte glycoprotein (MOG) IgG seropositivity is a prerequisite for MOG antibody-associated disease (MOGAD) diagnosis. While a significant proportion of patients experience a relapsing disease, there is currently no biomarker predictive of disease course. We aim to determine whether MOG-IgG epitopes can predict a relapsing course in MOGAD patients. METHODS: MOG-IgG-seropositive confirmed adult MOGAD patients were included (n=202). Serum MOG-IgG and epitope binding were determined by validated flow cytometry live cell-based assays. Associations between epitopes, disease course, clinical phenotype, Expanded Disability Status Scale and Visual Functional System Score at onset and last review were evaluated. RESULTS: Of 202 MOGAD patients, 150 (74%) patients had MOG-IgG that recognised the immunodominant proline42 (P42) epitope and 115 (57%) recognised histidine103/serine104 (H103/S104). Fifty-two (26%) patients had non-P42 MOG-IgG and showed an increased risk of a relapsing course (HR 1.7; 95% CI 1.15 to 2.60, p=0.009). Relapse-freedom was shorter in patients with non-P42 MOG-IgG (p=0.0079). Non-P42 MOG-IgG epitope status remained unchanged from onset throughout the disease course and was a strong predictor of a relapsing course in patients with unilateral optic neuritis (HR 2.7, 95% CI 1.06 to 6.98, p=0.038), with high specificity (95%, 95% CI 77% to 100%) and positive predictive value (85%, 95% CI 45% to 98%). CONCLUSIONS: Non-P42 MOG-IgG predicts a relapsing course in a significant subgroup of MOGAD patients. Patients with unilateral optic neuritis, the most frequent MOGAD phenotype, can reliably be tested at onset, regardless of age and sex. Early detection and specialised management in these patients could minimise disability and improve long-term outcomes.

Routine CSF parameters as predictors of disease course in multiple sclerosis: an MSBase cohort study.

BACKGROUND: It remains unclear whether routine cerebrospinal fluid (CSF) parameters can serve as predictors of multiple sclerosis (MS) disease course. METHODS: This large-scale cohort study included persons with MS with CSF data documented in the MSBase registry. CSF parameters to predict time to reach confirmed Expanded Disability Status Scale (EDSS) scores 4, 6 and 7 and annualised relapse rate in the first 2 years after diagnosis (ARR2) were assessed using (cox) regression analysis. RESULTS: In total, 11 245 participants were included of which 93.7% (n=10 533) were persons with relapsing-remitting MS (RRMS). In RRMS, the presence of CSF oligoclonal bands (OCBs) was associated with shorter time to disability milestones EDSS 4 (adjusted HR=1.272 (95% CI, 1.089 to 1.485), p=0.002), EDSS 6 (HR=1.314 (95% CI, 1.062 to 1.626), p=0.012) and EDSS 7 (HR=1.686 (95% CI, 1.111 to 2.558), p=0.014). On the other hand, the presence of CSF pleocytosis (≥5 cells/µL) increased time to moderate disability (EDSS 4) in RRMS (HR=0.774 (95% CI, 0.632 to 0.948), p=0.013). None of the CSF variables were associated with time to disability milestones in persons with primary progressive MS (PPMS). The presence of CSF pleocytosis increased ARR2 in RRMS (adjusted R2=0.036, p=0.015). CONCLUSIONS: In RRMS, the presence of CSF OCBs predicts shorter time to disability milestones, whereas CSF pleocytosis could be protective. This could however not be found in PPMS. CSF pleocytosis is associated with short-term inflammatory disease activity in RRMS. CSF analysis provides prognostic information which could aid in clinical and therapeutic decision-making.

Effectiveness of cladribine compared to fingolimod, natalizumab, ocrelizumab and alemtuzumab in relapsing-remitting multiple sclerosis.

BACKGROUND: Comparisons between cladribine and other potent immunotherapies for multiple sclerosis (MS) are lacking. OBJECTIVES: To compare the effectiveness of cladribine against fingolimod, natalizumab, ocrelizumab and alemtuzumab in relapsing-remitting MS. METHODS: Patients with relapsing-remitting MS treated with cladribine, fingolimod, natalizumab, ocrelizumab or alemtuzumab were identified in the global MSBase cohort and two additional UK centres. Patients were followed for ⩾6/12 and had ⩾3 in-person disability assessments. Patients were matched using propensity score. Four pairwise analyses compared annualised relapse rates (ARRs) and disability outcomes. RESULTS: The eligible cohorts consisted of 853 (fingolimod), 464 (natalizumab), 1131 (ocrelizumab), 123 (alemtuzumab) or 493 (cladribine) patients. Cladribine was associated with a lower ARR than fingolimod (0.07 vs. 0.12, p = 0.006) and a higher ARR than natalizumab (0.10 vs. 0.06, p = 0.03), ocrelizumab (0.09 vs. 0.05, p = 0.008) and alemtuzumab (0.17 vs. 0.04, p < 0.001). Compared to cladribine, the risk of disability worsening did not differ in patients treated with fingolimod (hazard ratio (HR) 1.08, 95% confidence interval (CI) 0.47-2.47) or alemtuzumab (HR 0.73, 95% CI 0.26-2.07), but was lower for patients treated with natalizumab (HR 0.35, 95% CI 0.13-0.94) and ocrelizumab (HR 0.45, 95% CI 0.26-0.78). There was no evidence for a difference in disability improvement. CONCLUSION: Cladribine is an effective therapy that can be viewed as a step up in effectiveness from fingolimod, but is less effective than the most potent intravenous MS therapies.

Rates of John Cunningham virus seroconversion greatly reduced in natalizumab-treated patients during COVID-19-related lockdowns.

BACKGROUND AND PURPOSE: This study was undertaken to retrospectively compare rates of John Cunningham virus (JCV) seroconversion in natalizumab-treated patients before and during COVID-19-related community restrictions. Natalizumab is highly effective therapy for relapsing-remitting multiple sclerosis. Prolonged exposure to natalizumab in JCV-positive patients can cause progressive multifocal leukoencephalopathy, a potentially fatal brain infection. Serial assessment of JCV status is required for patients receiving natalizumab. METHODS: Patients receiving natalizumab at the Royal Melbourne Hospital were assessed for change in JCV serostatus and duration of exposure to natalizumab in two discrete time periods: from 1 February 2012 until 1 February 2017 ("pre-COVID"; n = 128) and from 1 April 2020 until 12 October 2022 ("COVID"; n = 214). A Poisson regression model adjusted for age at natalizumab commencement and sex was used to model seroconversion rate between the two time periods. RESULTS: The pre-COVID JCV seroconversion rate among natalizumab-treated patients at the Royal Melbourne Hospital was 9.08%. Conversely, we found a precipitous decline in JCV seroconversion during COVID lockdown. Annualized seroconversion during COVID-19-related restrictions was 2.01%. The annualized seroconversion rate was 4.7 times higher during the pre-COVID-19 period (95% confidence interval = 2.96-7.45, p < 0.0001) compared to the annualized seroconversion rate during COVID lockdown. Males had a 2× higher rate of seroconversion compared to females. CONCLUSIONS: JCV seroconversion among natalizumab-treated patients was markedly lower during COVID-19-related community restrictions. Restrictions observed in Melbourne were among the longest and most comprehensive implemented worldwide. This suggests the presence of modifiable risk factors that could lower rates of JCV seroconversion among natalizumab-treated patients.

Patterns of neurotoxicity among patients receiving chimeric antigen receptor T-cell therapy: A single-centre cohort study.

BACKGROUND AND PURPOSE: Immune effector cell-associated neurotoxicity syndrome (ICANS) is an important complication of chimeric antigen receptor T-cell (CAR-T) therapy. This study aims to identify the patterns of neurotoxicity among patients with ICANS at a tertiary referral centre in Australia. METHODOLOGY: This single-centre, prospective cohort study included all consecutively recruited patients who underwent CAR-T therapy for eligible haematological malignancies. All patients underwent a comprehensive neurological assessment and cognitive screening before CAR-T infusion, during the development of ICANS, and 1 month after treatment. Baseline demographic characteristics, incidence, and neurological patterns of neurotoxicity management were evaluated. RESULTS: Over a 19-month period, 23% (12) of the 53 eligible patients developed neurotoxicity (10/12 [83%] being grade 1). All patients showed changes in handwriting and tremor as their initial presentation. Changes in cognition were manifested in most of the patients, with a more substantial drop noted in their Montreal Cognitive Assessment compared to immune effector cell-associated encephalopathy scores. All manifestations of neurotoxicity were short-lived and resolved within a 1-month period, with a mean duration of 8.2 days (range = 1-33). CONCLUSIONS: The patterns of CAR-T-related neurotoxicity often include change in handwriting, tremor, and mild confusional state, especially early in their evolution. These may remain undetected by routine neurological surveillance. These features represent accessible clinical markers of incipient ICANS.

The Patient-Determined Disease Steps scale is not interchangeable with the Expanded Disease Status Scale in mild to moderate multiple sclerosis.

BACKGROUND AND PURPOSE: The validity, reliability, and longitudinal performance of the Patient-Determined Disease Steps (PDDS) scale is unknown in people with multiple sclerosis (MS) with mild to moderate disability. We aimed to examine the psychometric properties and longitudinal performance of the PDDS. METHODS: We included relapsing-remitting MS patients with an Expanded Disability Status Scale (EDSS) score of less than 4. Validity and test-retest reliability was examined. Longitudinal data were analysed with mixed-effect modelling and Cohen's kappa for concordance in confirmed disability progression (CDP). RESULTS: We recruited a total of 1093 participants, of whom 904 had complete baseline data. The baseline correlation between PDDS and EDSS was weak (ρ = 0.45, p < 0.001). PDDS had stronger correlations with patient-reported outcomes (PROs). Conversely, EDSS had stronger correlations with age, disease duration, Kurtzke's functional systems and processing speed test. PDDS test-retest reliability was good to excellent (concordance correlation coefficient = 0.73-0.89). Longitudinally, PDDS was associated with EDSS, age and depression. A higher EDSS score was associated with greater PDSS progression. The magnitude of these associations was small. There was no concordance in CDP as assessed by PDDS and EDSS. CONCLUSION: The PDDS has greater correlation with other PROs but less correlation with other MS-related outcome measures compared to the EDSS. There was little correlation between PDDS and EDSS longitudinally. Our findings suggest that the PDDS scale is not interchangeable with the EDSS.

Observational studies of treatment effectiveness in neurology.

The capacity and power of data from cohorts, registries and randomized trials to provide answers to contemporary clinical questions in neurology has increased considerably over the past two decades. Novel sophisticated statistical methods are enabling us to harness these data to guide treatment decisions, but their complexity is making appraisal of clinical evidence increasingly demanding. In this review, we discuss several methodological aspects of contemporary research of treatment effectiveness in observational data in neurology, aimed at academic neurologists and analysts specializing in outcomes research. The review discusses specifics of the sources of observational data and their key features. It focuses on the limitations of observational data and study design, as well as statistical approaches aimed to overcome these limitations. Among the examples of leading clinical themes typically studied with analyses of observational data, the review discusses methodological approaches to comparative treatment effectiveness, development of diagnostic criteria and definitions of clinical outcomes. Finally, this review provides a brief summary of key points that will help clinical audience critically evaluate design and analytical aspects of studies of disease outcomes using observational data.

Not all roads lead to the immune system: the genetic basis of multiple sclerosis severity.

Multiple sclerosis is a leading cause of neurological disability in adults. Heterogeneity in multiple sclerosis clinical presentation has posed a major challenge for identifying genetic variants associated with disease outcomes. To overcome this challenge, we used prospectively ascertained clinical outcomes data from the largest international multiple sclerosis registry, MSBase. We assembled a cohort of deeply phenotyped individuals of European ancestry with relapse-onset multiple sclerosis. We used unbiased genome-wide association study and machine learning approaches to assess the genetic contribution to longitudinally defined multiple sclerosis severity phenotypes in 1813 individuals. Our primary analyses did not identify any genetic variants of moderate to large effect sizes that met genome-wide significance thresholds. The strongest signal was associated with rs7289446 (ß = -0.4882, P = 2.73 × 10-7), intronic to SEZ6L on chromosome 22. However, we demonstrate that clinical outcomes in relapse-onset multiple sclerosis are associated with multiple genetic loci of small effect sizes. Using a machine learning approach incorporating over 62 000 variants together with clinical and demographic variables available at multiple sclerosis disease onset, we could predict severity with an area under the receiver operator curve of 0.84 (95% CI 0.79-0.88). Our machine learning algorithm achieved positive predictive value for outcome assignation of 80% and negative predictive value of 88%. This outperformed our machine learning algorithm that contained clinical and demographic variables alone (area under the receiver operator curve 0.54, 95% CI 0.48-0.60). Secondary, sex-stratified analyses identified two genetic loci that met genome-wide significance thresholds. One in females (rs10967273; ßfemale = 0.8289, P = 3.52 × 10-8), the other in males (rs698805; ßmale = -1.5395, P = 4.35 × 10-8), providing some evidence for sex dimorphism in multiple sclerosis severity. Tissue enrichment and pathway analyses identified an overrepresentation of genes expressed in CNS compartments generally, and specifically in the cerebellum (P = 0.023). These involved mitochondrial function, synaptic plasticity, oligodendroglial biology, cellular senescence, calcium and G-protein receptor signalling pathways. We further identified six variants with strong evidence for regulating clinical outcomes, the strongest signal again intronic to SEZ6L (adjusted hazard ratio 0.72, P = 4.85 × 10-4). Here we report a milestone in our progress towards understanding the clinical heterogeneity of multiple sclerosis outcomes, implicating functionally distinct mechanisms to multiple sclerosis risk. Importantly, we demonstrate that machine learning using common single nucleotide variant clusters, together with clinical variables readily available at diagnosis can improve prognostic capabilities at diagnosis, and with further validation has the potential to translate to meaningful clinical practice change.

Language impairments in seropositive and seronegative autoimmune encephalitis.

BACKGROUND AND OBJECTIVE: Autoimmune encephalitis (AE) is a rare neuroinflammatory disease affecting the central nervous system. To examine language functions in patients with different subsets of AE consisting of seropositive and seronegative groups. METHODS: Fifty-two patients were recruited from neurology departments in Melbourne, Australia, who met clinical criteria for possible AE. Language tests include the Naming Test from the Sydney Language Battery (SydBat), the semantic fluency trial from the Controlled Oral Word Association Test (COWAT), and the Vocabulary and Similarities subtests of the Weschler Abbreviated Scale of Intelligence-Second Edition. The results were standardised with normative data. RESULTS: The mean age of our cohort was 52.5 years old, with the average time from hospital admission to recruitment being 38.41 months. At an aggregate level, none of the mean language test z-scores were below normative data. At the patient level, impairment rates were 18.37% for COWAT (animals), 28.57% for SydBat (naming), 4.65% for Similarities, and 4.55% for Vocabulary. Chi-squared goodness of fit tests indicated that observed performances were significantly below expected performances for the SydBat (naming) test (p < 0.0001) and COWAT (animals) (p = 0.004). DISCUSSION: While, on average, language functions were within normal limits in patients with AE, but a subgroup exhibited lower performance in semantic fluency and visual confrontation naming, with impairment rates below expected norms. To advance understanding of language in chronic AE patients, exploring the impact of seizure burden, antiseizure medication use, and the relationship of language functions with other cognitive functions is crucial.

Plasma neurofilament light in behavioural variant frontotemporal dementia compared to mood and psychotic disorders.

OBJECTIVE: Blood biomarkers of neuronal injury such as neurofilament light (NfL) show promise to improve diagnosis of neurodegenerative disorders and distinguish neurodegenerative from primary psychiatric disorders (PPD). This study investigated the diagnostic utility of plasma NfL to differentiate behavioural variant frontotemporal dementia (bvFTD, a neurodegenerative disorder commonly misdiagnosed initially as PPD), from PPD, and performance of large normative/reference data sets and models. METHODS: Plasma NfL was analysed in major depressive disorder (MDD, n = 42), bipolar affective disorder (BPAD, n = 121), treatment-resistant schizophrenia (TRS, n = 82), bvFTD (n = 22), and compared to the reference cohort (Control Group 2, n = 1926, using GAMLSS modelling), and age-matched controls (Control Group 1, n = 96, using general linear models). RESULTS: Large differences were seen between bvFTD (mean NfL 34.9 pg/mL) and all PPDs and controls (all < 11 pg/mL). NfL distinguished bvFTD from PPD with high accuracy, sensitivity (86%), and specificity (88%). GAMLSS models using reference Control Group 2 facilitated precision interpretation of individual levels, while performing equally to or outperforming models using local controls. Slightly higher NfL levels were found in BPAD, compared to controls and TRS. CONCLUSIONS: This study adds further evidence on the diagnostic utility of NfL to distinguish bvFTD from PPD of high clinical relevance to a bvFTD differential diagnosis, and includes the largest cohort of BPAD to date. Using large reference cohorts, GAMLSS modelling and the interactive Internet-based application we developed, may have important implications for future research and clinical translation. Studies are underway investigating utility of plasma NfL in diverse neurodegenerative and primary psychiatric conditions in real-world clinical settings.

Sample Entropy Improves Assessment of Postural Control in Early-Stage Multiple Sclerosis.

Postural impairment in people with multiple sclerosis (pwMS) is an early indicator of disease progression. Common measures of disease assessment are not sensitive to early-stage MS. Sample entropy (SE) may better identify early impairments. We compared the sensitivity and specificity of SE with linear measurements, differentiating pwMS (EDSS 0-4) from healthy controls (HC). 58 pwMS (EDSS ≤ 4) and 23 HC performed quiet standing tasks, combining a hard or foam surface with eyes open or eyes closed as a condition. Sway was recorded at the sternum and lumbar spine. Linear measures, mediolateral acceleration range with eyes open, mediolateral jerk with eyes closed, and SE in the anteroposterior and mediolateral directions were calculated. A multivariate ANOVA and AUC-ROC were used to determine between-groups differences and discriminative ability, respectively. Mild MS (EDSS ≤ 2.0) discriminability was secondarily assessed. Significantly lower SE was observed under most conditions in pwMS compared to HC, except for lumbar and sternum SE when on a hard surface with eyes closed and in the anteroposterior direction, which also offered the strongest discriminability (AUC = 0.747), even for mild MS. Overall, between-groups differences were task-dependent, and SE (anteroposterior, hard surface, eyes closed) was the best pwMS classifier. SE may prove a useful tool to detect subtle MS progression and intervention effectiveness.

Plasma and CSF neurofilament light chain distinguish neurodegenerative from primary psychiatric conditions in a clinical setting.

INTRODUCTION: People with neurodegenerative disorders (ND) frequently face diagnostic delay and misdiagnosis. We investigated blood and cerebrospinal fluid (CSF) neurofilament light chain (NfL) to distinguish ND from primary psychiatric disorders (PPD), a common challenge in clinical settings. METHODS: Plasma and CSF NfL levels were measured and compared between groups, adjusting for age, sex, and weight. RESULTS: A total of 337 participants were included: 136 ND, 77 PPD, and 124 Controls. Plasma NfL was 2.5-fold elevated in ND compared to PPD and had strong diagnostic performance (area under the curve, [AUC]: 0.86, 81%/85% specificity/sensitivity) that was comparable to CSF NfL (2-fold elevated, AUC: 0.89, 95%/71% specificity/sensitivity). Diagnostic performance was especially strong in younger people (40- < 60 years). Additional findings were cutoffs optimized for sensitivity and specificity, and issues important for future clinical translation. CONCLUSIONS: This study adds important evidence for a simple blood-based biomarker to assist as a screening test for neurodegeneration and distinction from PPD, in clinical settings. HIGHLIGHTS: NfL levels were significantly higher in ND versus PPD. Plasma NfL showed strong diagnostic performance, comparable to CSF NfL, to distinguish ND from PPD. Diagnostic performance was higher in younger people, where diagnostic challenges are greater. Further research is needed on analytical and reference range factors, for clinical translation. These findings support a simple screening blood test for neurodegeneration.