Importance:The value of serum neurofilament light chain (sNfL) levels for predicting long-term disability in patients with multiple sclerosis (MS) remains controversial.Objective:To assess whether high sNfL values are associated with disability worsening in patients who underwent their first demyelinating MS event.Design, Setting, and Participants:This multicenter cohort study included patients who underwent their first demyelinating event suggestive of MS at Hospital Universitario Ramón y Cajal (development cohort; June 1, 1994, to September 31, 2021, with follow-up until August 31, 2022) and 8 Spanish hospitals (validation cohort; October 1, 1995, to August 4, 2020, with follow-up until August 16, 2022).Exposures:Clinical evaluations at least every 6 months.Main Outcomes and Measures:The main outcomes were 6-month confirmed disability worsening (CDW) and an Expanded Disability Status Scale (EDSS) score of 3. Levels of sNfL were measured in blood samples obtained within 12 months after disease onset using a single molecule array kit. The cutoffs used were sNfL level of 10 pg/mL and a standardized score (z score) of 1.5. Multivariable Cox proportional hazards regression models were used to evaluate outcomes.Results:Of the 578 patients included in the study, 327 were in the development cohort (median age at sNfL analysis, 34.1 years [IQR, 27.2-42.7 years]; 226 female [69.1%]) and 251 patients were in the validation cohort (median age at sNfL analysis, 33.3 years [IQR, 27.4-41.5 years]; 184 female [73.3%]). The median follow-up was 7.10 years (IQR, 4.18-10.0 years). Levels of sNfL greater than 10 pg/mL were independently associated with higher risk of 6-month CDW and an EDSS of 3 in the development cohort (6-month CDW: hazard ratio [HR], 2.39; 95% CI, 1.39-4.12; P = .002; EDSS of 3: HR, 4.12; 95% CI, 2.18-7.77; P < .001) and the validation cohort (6-month CDW: HR, 1.61; 95% CI, 1.07-2.42; P = .02; EDSS of 3: HR, 2.03; 95% CI, 1.23-3.33; P = .005). Highly effective disease-modifying treatments were associated with lower risks of 6-month CDW and an EDSS of 3 in patients with high baseline sNfL values.Conclusions and Relevance:This cohort study found that high sNfL values obtained within the first year of disease were associated with long-term disability worsening in MS, suggesting that sNfL level measurement may help identify optimal candidates for highly effective disease-modifying treatments.

Objective To determine the best method to measure intrathecal immunoglobulin (Ig) M synthesis (ITMS), a biomarker of worse prognosis in multiple sclerosis (MS). We compared the ability for predicting a poor evolution of 4 methods assessing ITMS (IgM oligoclonal bands [OCMBs], lipid-specific OCMBs [LS-OCMBs], Reibergram, and IgM index) in patients with a clinically isolated syndrome (CIS). Methods Prospective study with consecutive patients performed at a referral MS center. We used unadjusted and multivariate Cox regressions for predicting a second relapse, Expanded Disability Status Scale (EDSS) scores of 4 and 6, and development of secondary progressive MS (SPMS). Results A total of 193 patients were included, with a median (interquartile range) age of 31 (25-38) years and a median follow-up of 12.9 years. Among all methods, only OCMB, LS-OCMB, and Reibergram significantly identified patients at risk of some of the pre-established outcomes, being LS-OCMB the technique with the strongest associations. Adjusted hazard ratio (aHR) of LS-OCMB for predicting a second relapse was 2.50 (95% CI 1.72-3.64, p < 0.001). The risk of reaching EDSS scores of 4 and 6 and SPMS was significantly higher among patients with LS-OCMB (aHR 2.96, 95% CI 1.54-5.71, p = 0.001; aHR 4.96, 95% CI 2.22-11.07, p < 0.001; and aHR 2.31, 95% CI 1.08-4.93, p = 0.03, respectively). Conclusions ITMS predicts an aggressive MS at disease onset, especially when detected as LS-OCMB. Classification of Evidence This study provides Class II evidence that lipid-specific IgM oligoclonal bands can predict progression from CIS to MS and a worse disease course over a follow-up of at least 2 years.

Patients with multiple sclerosis (MS) suffer with age an early immunosenescence process, which influence the treatment response and increase the risk of infections. We explored whether lipid-specific oligoclonal IgM bands (LS-OCMB) associated with highly inflammatory MS modify the immunological profile induced by age in MS. This cross-sectional study included 263 MS patients who were classified according to the presence (M+, n=72) and absence (M-, n=191) of LS-OCMB. CSF cellular subsets and molecules implicated in immunosenescence were explored. In M- patients, aging induced remarkable decreases in absolute CSF counts of CD4+ and CD8+ T lymphocytes, including Th1 and Th17 cells, and of B cells, including those secreting TNF-alpha. It also increased serum anti-CMV IgG antibody titers (indicative of immunosenescence) and CSF CHI3L1 levels (related to astrocyte activation). In contrast, M+ patients showed an age-associated increase of TIM-3 (a biomarker of T cell exhaustion) and increased values of CHI3L1, independently of age. Finally, in both groups, age induced an increase in CSF levels of PD-L1 (an inductor of T cell tolerance) and activin A (part of the senescence-associated secretome and related to inflammaging). These changes were independent of the disease duration. Finally, this resulted in augmented disability. In summary, all MS patients experience with age a modest induction of T-cell tolerance and an activation of the innate immunity, resulting in increased disability. Additionally, M- patients show clear decreases in CSF lymphocyte numbers, which could increase the risk of infections. Thus, age and immunological status are important for tailoring effective therapies in MS.

Background Gut microbiota has been related to multiple sclerosis (MS) etiopathogenesis. Short-chain fatty acids (SCFA) are compounds derived from microbial metabolism that have a role in gut-brain axis. Objectives To analyse SCFA levels in plasma of MS patients and healthy donors (HD), and the possible link between these levels and both clinical data and immune cell populations. Methods Ninety-five MS patients and 54 HD were recruited. Patients were selected according to their score in the Expanded Disability Status Scale (EDSS) (49 EDSS ≤ 1.5, 46 EDSS ≥ 5.0). SCFA were studied in plasma samples by liquid chromatography-mass spectrometry. Peripheral blood mononuclear cells were studied by flow cytometry. Gender, age, treatments, EDSS and Multiple Sclerosis Severity Score (MSSS) were evaluated at the recruitment. Results Plasma acetate levels were higher in patients than in HD ( p = 0.003). Patients with EDSS ≥ 5.0 had higher acetate levels than those with EDSS≤ 1.5 ( p = 0.029), and HD ( p = 2.97e–4). Acetate levels correlated with EDSS ( r = 0.387; p = 1.08e–4) and MSSS ( r = 0.265; p = 0.011). In untreated MS patients, acetate levels correlated inversely with CD4+ naïve T cells ( r = − 0.550, p = 0.001) and directly with CD8+ IL-17+ cells ( r = 0.557; p = 0.001). Conclusions Plasma acetate levels are higher in MS patients than in HD. In MS there exists a correlation between plasma acetate levels, EDSS and increased IL-17+ T cells. Future studies will elucidate the role of SCFA in the disease.

Background: The Multiple Sclerosis Severity Score (MSSS) is a widely used measure of the disability progression rate. However, the global MSSS may not be the best basis for comparison between all patient groups. Objective: We evaluated sex-specific and onset phenotype–specific MSSS matrices to determine if they were more effective than the global MSSS as a basis for comparison within these subsets. Methods: Using a large international dataset of multiple sclerosis (MS) patient records and the original MSSS algorithm, we constructed global, sex-specific and onset phenotype–specific MSSS matrices. We compared matrices using permutation analysis. Results: Our final dataset included 30,203 MS cases, with 28.9% males and 6.5% progressive-onset cases. Our global MSSS matrix did not differ from previously published data ( p > 0.05). The progressive-onset-specific matrix differed significantly from the relapsing-onset-specific matrix ( p < 0.001), with lower MSSS attributed to cases with the same Expanded Disability Status Score (EDSS) and disease duration. When evaluated with a simulation, using an onset-specific MSSS improved statistical power in mixed cohorts. There were no significant differences by sex. Conclusion: The differences in the disability accrual rate between progressive- and relapsing-onset MS have a significant effect on MSSS. An onset-specific MSSS should be used when comparing the rate of disability progression among progressive-onset cases and for mixed cohorts.

Background: There is a lack of head-to-head studies comparing the efficacy of fingolimod (FIN) and natalizumab (NTZ) as second-line therapy for relapsing-remitting multiple sclerosis (RRMS). Methods: Multicenter, observational study, in which, information of 388 patients randomly selected and treated with FIN or NTZ in routine clinical practice was retrospectively collected with the main objective of comparing the annualized relapse rate (ARR) over the first year, after FIN or NTZ treatment initiation. Results: Mean ARR during the first year of treatment was 0.28 in FIN group and 0.12 in NTZ group (p = 0.0064); nevertheless, the difference between groups lost statistical significance when the propensity score analysis was performed. Time to disability ­progression was similar in both treatment groups (12.3 ± 6.7 months in FIN, and 12.8 ± 0.1 months in NTZ; p = 0.4654). Treatment persistence after the first year of treatment was higher in patients treated with FIN (95%) than in those treated with NTZ (84%; p = 0.0014). Conclusions: After 12 months of treatment, both FIN and NTZ reduced the ARR, but ARR percent reduction was significantly higher with NTZ. Treatment persistence was higher in patients receiving FIN.

There are an increasing number of treatments available for multiple sclerosis (MS). The early identification of optimal responders to individual treatments is important to achieve individualized therapy. With this aim, we performed a multicenter retrospective longitudinal study including 186 MS patients treated with natalizumab who were followed for 2 years. We analyzed the following variables at recruitment: sex, current age, age at disease onset, disease duration, EDSS, number of T2 and Gd + lesions, IgG and IgM oligoclonal bands, HLA class II (DR, DRB, DQA, DQB, and DRB1*15:01), IgG and IgM antibody titers against human herpesvirus 6 (HHV-6) and the antibody response to Epstein–Barr virus (EBV) through the measurement of the anti-EBNA-1 and anti-VCA IgG titers, in relation to clinical response (no relapses or disability progression), and to NEDA-3 (no evidence of disease activity in terms of clinical response and no changes in MRI scans either) after 2-years follow-up. Baseline EDSS score, baseline EBNA-1 IgG titers and percentage change of HHV6 IgG titers between baseline and 6 month visits were significantly different in clinical responders and in NEDA-3 status (all of them remained significant in the multivariate analysis). We identified three variables for the early identification of natalizumab optimal responders in a rapid and cost-effective approach.

Overview: We assessed the role of age and disease activity as new factors contributing to establish the risk of progressive multifocal leucoencephalopathy in multiple sclerosis patients treated with natalizumab in 36 University Hospitals in Europe. We performed the study in 1,307 multiple sclerosis patients (70.8% anti-John Cunninghan virus positive antibodies) treated with natalizumab for a median time of 3.28 years. Epidemiological, clinical, and laboratory variables were collected. Lipid-specific IgM oligoclonal band status was available in 277 patients. Factors associated with progressive multifocal leucoencephalopathy onset were explored by uni- and multivariate logistic regression. Results: Thirty-five patients developed progressive multifocal leucoencephalopathy. The multivariate analysis identified anti-John Cunninghan virus antibody indices and relapse rate as the best predictors for the onset of this serious opportunistic infection in the whole cohort. They allowed to stratify progressive multifocal leucoencephalopathy risk before natalizumab initiation in individual patients [area under the curve (AUC) = 0.85]. The risk ranged from <1/3,300 in patients with anti-John Cunninghan virus antibody indices <0.9 and relapse rate >0.5, to 1/50 in the opposite case. In patients with lipid-specific IgM oligoclonal bands assessment, age at natalizumab onset, anti-John Cunninghan virus antibody indices, and lipid-specific IgM oligoclonal band status predicted progressive multifocal leucoencephalopathy risk (AUC = 0.92). The absence of lipid-specific IgM oligoclonal bands was the best individual predictor (OR = 40.94). The individual risk ranged from <1/10,000 in patients younger than 45 years at natalizumab initiation, who showed anti John Cunningham virus antibody indices <0.9 and lipid-specific IgM oligoclonal bands to 1/33 in the opposite case. Conclusions: In a perspective of personalized medicine, disease activity, anti-lipid specific IgM oligoclonal bands, anti Jonh Cunninghan virus antibody levels, and age can help tailor natalizumab therapy in multiple sclerosis patients, as predictors of progressive multifocal leucoencephalopathy.

Introduction. Cladribine is a prodrug, a synthetic analogue of deoxyadenosine, approved for use as selective immune reconstitution therapy in very active recurring multiple sclerosis in adults. Aims. To review the development of the drug, its mechanism of action and the efficacy and safety data obtained to date, as well as to establish recommendations of Spanish experts for its use in clinical practice. Development. The treatment of multiple sclerosis has been simplified with cladribine tablets, and two short courses of administration for two consecutive years (maximum 20 days) are needed to maintain an efficacy of up to four years after the first dose. Results of clinical trials have demonstrated the safety, tolerability and long-term efficacy of cladribine tablets in patients with recurring multiple sclerosis. Thus, patients treated with cladribine presented a significant reduction in the rate of flare-ups, in the risk of disability progression and in the development of new lesions in magnetic resonance imaging compared to those treated with placebo. In terms of safety, the treated patients had a higher frequency of lymphopenia, in relation to its mechanism of action, and of infections by herpes zoster virus. Long-term results with eight years' follow-up have shown that treated patients are not at greater risk of developing serious events, such as malignant neoplasms or opportunistic infections. Conclusions. Cladribine is the first short-course oral therapy that has been shown to be effective and safe in patients with very active recurring multiple sclerosis, and with a sustained effect over time. The recommendations of Spanish experts on its usage are a fundamental complement to the considerations described by the regulatory agencies.

Objectives:Teriflunomide, a disease-modifying treatment approved for multiple sclerosis (MS), inhibits reversibly dihydroorotate dehydrogenase, an enzyme involved in de novo pyrimidine biosynthesis and down-regulates proliferation of activated lymphocytes. We aimed to study the impact of this drug in the lymphocyte profiles of MS patients.Methods:Fifty-five patients with relapsing-remitting MS who initiated teriflunomide treatment were included in the study. We studied peripheral blood mononuclear cells obtained before and 6 months after treatment initiation and explored effector, memory, and regulatory cells by flow cytometry. Wilcoxon matched pair tests were used to assess differences between basal and 6 months after treatment results. P-values were corrected with Bonferroni test.Results:When explored T and B cell subsets, we observed a decrease in the percentages of terminally differentiated CD4+ T cells (P = 0.001) and plasmablasts (P < 0.0001) after 6 months of treatment. These results were confirmed with the total cell number. When studied immunomodulatory cells, we observed a clear increase of monocytes expressing programmed death-ligand 1 (PD-L1) (P = 0.005), which correlated negatively with all effector CD8+ T cell subsets. We also observed an increase in the percentage of CD8+ T cells (P = 0.028) and monocytes (P = 0.04) producing IL-10.Conclusions:Teriflunomide induces a specific reduction in effector T and B cells that have shown to play a role in MS course and an increase in immunomodulatory cells. Particularly, this drug induces the expression of PD-L1, a molecule involved in tolerance to autoantigens, which can contribute to inhibit the abnormal immune response taking place in MS.

Gut microbiota dysbiosis has been implicated in MS and other immune diseases, although it remains unclear how manipulating the gut microbiota may affect the disease course. Using a well-established model of progressive MS triggered by intracranial infection with Theiler's murine encephalomyelitis virus (TMEV), we sought to determine whether dysbiosis induced by oral antibiotics (ABX) administered on pre-symptomatic and symptomatic phases of the disease influences its course. We also addressed the effects of microbiota recolonization after ABX withdrawn in the presence or absence of probiotics. Central and peripheral immunity, plasma acetate and butyrate levels, axon damage and motor disability were evaluated. The cocktail of ABX prevented motor dysfunction and limited axon damage in mice, which had fewer CD4+ and CD8+ T cells in the CNS, while gut microbiota recolonization worsened motor function and axonal integrity. The underlying mechanisms of ABX protective effects seem to involve CD4+CD39+ T cells and CD5+CD1d+ B cells into the CNS. In addition, microglia adopted a round amoeboid morphology associated to an anti-inflammatory gene profile in the spinal cord of TMEV mice administered ABX. The immune changes in the spleen and mesenteric lymph nodes were modest, yet ABX treatment of mice limited IL-17 production ex vivo. Collectively, our results provide evidence of the functional relevance of gut microbiota manipulation on the neurodegenerative state and disease severity in a model of progressive MS and reinforce the role of gut microbiota as target for MS treatment.

Importance Neurofilament light protein (NfL) is elevated in cerebrospinal fluid (CSF) of a number of neurological conditions compared with healthy controls (HC) and is a candidate biomarker for neuroaxonal damage. The influence of age and sex is largely unknown, and levels across neurological disorders have not been compared systematically to date. Objectives To assess the associations of age, sex, and diagnosis with NfL in CSF (cNfL) and to evaluate its potential in discriminating clinically similar conditions. Data Sources PubMed was searched for studies published between January 1, 2006, and January 1, 2016, reporting cNfL levels (using the search terms neurofilament light and cerebrospinal fluid) in neurological or psychiatric conditions and/or in HC. Study Selection Studies reporting NfL levels measured in lumbar CSF using a commercially available immunoassay, as well as age and sex. Data Extraction and Synthesis Individual-level data were requested from study authors. Generalized linear mixed-effects models were used to estimate the fixed effects of age, sex, and diagnosis on log-transformed NfL levels, with cohort of origin modeled as a random intercept. Main Outcome and Measure The cNfL levels adjusted for age and sex across diagnoses. Results Data were collected for 10 059 individuals (mean [SD] age, 59.7 [18.8] years; 54.1% female). Thirty-five diagnoses were identified, including inflammatory diseases of the central nervous system (n = 2795), dementias and predementia stages (n = 4284), parkinsonian disorders (n = 984), and HC (n = 1332). The cNfL was elevated compared with HC in a majority of neurological conditions studied. Highest levels were observed in cognitively impaired HIV-positive individuals (iHIV), amyotrophic lateral sclerosis, frontotemporal dementia (FTD), and Huntington disease. In 33.3% of diagnoses, including HC, multiple sclerosis, Alzheimer disease (AD), and Parkinson disease (PD), cNfL was higher in men than women. The cNfL increased with age in HC and a majority of neurological conditions, although the association was strongest in HC. The cNfL overlapped in most clinically similar diagnoses except for FTD and iHIV, which segregated from other dementias, and PD, which segregated from atypical parkinsonian syndromes. Conclusions and Relevance These data support the use of cNfL as a biomarker of neuroaxonal damage and indicate that age-specific and sex-specific (and in some cases disease-specific) reference values may be needed. The cNfL has potential to assist the differentiation of FTD from AD and PD from atypical parkinsonian syndromes.

Background: Lymphopenia is a major concern in MS patients treated with dimethyl-fumarate (DMF) as it increases the risk of progressive multifocal leukoencephalopathy. Objective: To identify factors associated with lymphopenia in DMF-treated patients and explore changes in blood lymphocyte subsets associated with DMF-induced lymphopenia. Methods: Prospective longitudinal study including 106 patients initiating DMF treatment followed for a median time of 24.67 months. Blood lymphocyte subsets were studied in 64 patients by flow cytometry at baseline and 6 months after. Results: Mean absolute lymphocyte counts (ALCs) decreased by 29% during the first year of DMF-treatment. Patients developing lymphopenia showed a faster decline within the three first months. A reduction of ALCs higher than 38% at this time was associated to subsequent development of grade 2-3 lymphopenia (OR = 5.93, 95% CI: 1.9-18.6, p = 0.002). All patients showed a significant decrease in different T and B lymphocyte subsets upon DMF therapy. In addition, lymphopenic patients experienced a selective decrease in natural killer T (NKT) cell percentages (p = 0.01), and a high drop in NKT total counts (p < 0.0001). Conclusions: Patients who experience a drop in ALCs by > 38% at three months of DMF-treatment are about 6 times more likely to develop significant lymphopenia. This decrease is clearly associated with a considerable loss of NKT cells.

Background: Multiple sclerosis (MS) is a disease in which biomarker identification is fundamental to predict response to treatments and to deliver the optimal drug to patients. We previously found an association between rs7298096, a polymorphism upstream to theNINJ2gene, and the 4-year response to interferon-beta (IFN beta) treatment in MS patients. Objectives: To analyse the association between rs7298096 and time to first relapse (TTFR) during IFN beta therapy in MS patients and to better investigate its functional role. Methods: Survival analysis was applied in three MS cohorts from different countries (n = 1004). We also studied the role of the polymorphism on gene expression using GTEx portal and a luciferase assay. We interrogated GEO datasets to explore the relationship betweenNINJ2expression, IFN beta and TTFR. Results: Rs7298096(AA)patients show a shorter TTFR than rs7298096(G)-carriers (Pmeta-analysis = 3 x 10(-4), hazard ratio = 1.41). Moreover, rs7298096(AA)is associated with a higherNINJ2expression in blood (p = 7.0 x 10(-6)), which was confirmed in vitro (p = 0.009). Finally,NINJ2expression is downregulated by IFN beta treatment and related to TTFR. Conclusions: Rs7298096 could influence MS disease activity during IFN beta treatment by modulatingNINJ2expression in blood. The gene encodes for an adhesion molecule involved in inflammation and endothelial cells activation, supporting its role in MS.

Supplemental material, MSJ881994_supplementary_material for Redefining the Multiple Sclerosis Severity Score (MSSS): The effect of sex and onset phenotype by Yuan Zhou, Suzi B Claflin, Jim Stankovich, Ingrid van der Mei, Steve Simpson, Richard H Roxburgh, Tomas Kalincik, Leigh Blizzard, Alessandra Lugaresi, Raed Alroughani, Seyed Aidin Sajedi, Helmut Butzkueven, Eugenio Pucci, Daniele LA Spitaleri, Franco Granella, Edgardo Cristiano, Bassem Yamout, Stella Hughes, Riadh Gouider, Jose Luis Sanchez Menoyo, Javier Olascoaga, Chris McGuigan, Cameron Shaw, Allan G Kermode, Krisztian Kasa, Talal Al-Harbi, Ayse Altintas, Guy Laureys, Yara Fragoso, Todd A Hardy, Tunde Csepany, Carmen-Adella Sirbu, Danny Decoo, Attila Sas, Jose C Alvarez-Cermeno, Karim Kotkata, Jorge Millan-Pascual and Bruce V Taylor in Multiple Sclerosis Journal