Multiple sclerosis (OMIM 126200) is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability.1 Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals;2,3 and systematic attempts to identify linkage in multiplex families have confirmed that variation within the Major Histocompatibility Complex (MHC) exerts the greatest individual effect on risk.4 Modestly powered Genome-Wide Association Studies (GWAS)5-10 have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects play a key role in disease susceptibility.11 Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the Class I region. Immunologically relevant genes are significantly over-represented amongst those mapping close to the identified loci and particularly implicate T helper cell differentiation in the pathogenesis of multiple sclerosis.

The Multiple Sclerosis Severity Score (MSSS) is a powerful method for comparing disease progression using single assessment data. The Global MSSS can be used as a reference table for future disability comparisons. While useful for comparing groups of patients, disease fluctuation precludes its use as a predictor of future disability in an individual.

During early embryogenesis, microglia arise from yolk sac progenitors that populate the developing central nervous system (CNS), but how the tissue-resident macrophages are maintained throughout the organism's lifespan still remains unclear. Here, we describe a system that allows specific, conditional ablation of microglia in adult mice. We found that the microglial compartment was reconstituted within 1 week of depletion. Microglia repopulation relied on CNS-resident cells, independent from bone-marrow-derived precursors. During repopulation, microglia formed clusters of highly proliferative cells that migrated apart once steady state was achieved. Proliferating microglia expressed high amounts of the interleukin-1 receptor (IL-1R), and treatment with an IL-1R antagonist during the repopulation phase impaired microglia proliferation. Hence, microglia have the potential for efficient self-renewal without the contribution of peripheral myeloid cells, and IL-1R signaling participates in this restorative proliferation process.

More than 800 published genetic association studies have implicated dozens of potential risk loci in Parkinson's disease (PD). To facilitate the interpretation of these findings, we have created a dedicated online resource, PDGene, that comprehensively collects and meta-analyzes all published studies in the field. A systematic literature screen of ∼27,000 articles yielded 828 eligible articles from which relevant data were extracted. In addition, individual-level data from three publicly available genome-wide association studies (GWAS) were obtained and subjected to genotype imputation and analysis. Overall, we performed meta-analyses on more than seven million polymorphisms originating either from GWAS datasets and/or from smaller scale PD association studies. Meta-analyses on 147 SNPs were supplemented by unpublished GWAS data from up to 16,452 PD cases and 48,810 controls. Eleven loci showed genome-wide significant (P<5×10−8) association with disease risk: BST1, CCDC62/HIP1R, DGKQ/GAK, GBA, LRRK2, MAPT, MCCC1/LAMP3, PARK16, SNCA, STK39, and SYT11/RAB25. In addition, we identified novel evidence for genome-wide significant association with a polymorphism in ITGA8 (rs7077361, OR 0.88, P = 1.3×10−8). All meta-analysis results are freely available on a dedicated online database (www.pdgene.org), which is cross-linked with a customized track on the UCSC Genome Browser. Our study provides an exhaustive and up-to-date summary of the status of PD genetics research that can be readily scaled to include the results of future large-scale genetics projects, including next-generation sequencing studies.

Repair processes that are activated in response to neuronal injury, be it inflammatory, ischaemic, metabolic, traumatic or other cause, are characterized by a failure to replenish neurons and by astrogliosis. The underlying molecular pathways, however, are poorly understood. Here, we show that subtle alterations of the redox state, found in different brain pathologies, regulate the fate of mouse neural progenitor cells (NPCs) through the histone deacetylase (HDAC) Sirt1. Mild oxidation or direct activation of Sirt1 suppressed proliferation of NPCs and directed their differentiation towards the astroglial lineage at the expense of the neuronal lineage, whereas reducing conditions had the opposite effect. Under oxidative conditions in vitro and in vivo, Sirt1 was upregulated in NPCs, bound to the transcription factor Hes1 and subsequently inhibited pro-neuronal Mash1. In utero shRNA-mediated knockdown of Sirt1 in NPCs prevented oxidation-mediated suppression of neurogenesis and caused upregulation of Mash1 in vivo. Our results provide evidence for an as yet unknown metabolic master switch that determines the fate of neural progenitors.

Background and scopeMultiple sclerosis (MS) is an inflammatory-demyelinating disease of the central nervous system (CNS) that is characterized by inflammation, demyelination and degenerative changes. MS usually begins around the age between 20 and 40 years and affects two to three times as many women as men; it also constitutes the most frequent cause of non-traumatic disability in the young adult population. 1 The incidence of MS varies across regions, with rates as high as 8 to 10 new cases per 100,000 in high latitudinal regions. 2,3 Current estimates suggest that over 700,000 people are affected in Europe, with over 2.5 million cases worldwide, 4 which represent a significant burden in terms of impact on quality of life, societal costs and personal expenses. 5,6 Most patients (85%-90%) have a relapsing course from onset that is characterized by relapses and remissions of neurological symptoms Methods: This guideline has been developed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology and following the updated EAN recommendations. Clinical questions were formulated in Patients-Intervention-Comparator-Outcome (PICO) format and outcomes were prioritized. The quality of evidence was rated into four categories according to the risk of bias. The recommendations with assigned strength (strong and weak) were formulated based on the quality of evidence and the risk-benefit balance. Consensus between the panelists was reached by use of the modified nominal group technique. Results: A total of 10 questions were agreed, encompassing treatment efficacy, response criteria, strategies to address suboptimal response and safety concerns and treatment strategies in MS and pregnancy. The guideline takes into account all disease-modifying drugs approved by the European Medicine Agency (EMA) at the time of publication. A total of 21 recommendations were agreed by the guideline working group after three rounds of consensus. Conclusion:The present guideline will enable homogeneity of treatment decisions across Europe. associated with areas of CNS inflammation, and over the course of two decades, more than half of untreated patients transition to a phase of gradual worsening independent of acute attacks. 7,8 Progressive forms of MS can be present as the initial disease course (primary-progressive MS) in approximately 10%-15% of patients. 9,10 There is no curative treatment available for MS, and the current therapeutic strategy is aimed at reducing the risk of relapses and potentially disability progression. The treatment era for MS began in 1993, when the first interferon became available, and recent years have seen a large expansion in the therapeutic options for MS, with 11 disease-modifying therapies (DMTs) approved by the European Medicine Agency (EMA) in both injectable and oral formulations by the beginning of 2017. 11 The growing armamentarium of therapies brings new opportunities for individualized therapy where patients and providers must balance considerations around efficacy,...

Background and purpose: Multiple sclerosis (MS) is a complex disease with new drugs becoming available in the past years. There is therefore a need for a reference tool compiling current data to aid professionals in treatment decisions. The objective was to develop an evidence-based clinical practice guideline for the pharmacological treatment of people with MS. Methods: This guideline has been developed using the GRADE methodology and following the updated EAN recommendations for guideline development. Clinical questions were formulated in PICO format (patient, intervention, comparator, outcome) and outcomes were prioritized according to their relevance to clinical practice. Literature searches up to December 2016 were performed and the evidence is presented narratively and, when possible, combined in a fax: +34 93 2746084; e-mail: xavier.montalban@cem-cat.org) and for EAN: R. Gold, Department of Neurology, Ruhr University, St Josef-Hospital, Gudrunstr. 56, 44791 Bochum, Germany (tel.: +49-234-509244; fax: +49-234-5092414; e-mail: ralf.gold@rub.de). This is a Continuing Medical Education article, and can be found with corresponding questions on the EAN website, LEARN section https://www.ean. org/CME.2714.0.html. Certificates for correctly answered questions will be issued by EAN directly, you simply have to be logged-in. With positive results, EAN recommends accreditation of 1 hour of CME, which may be claimed with the national body in charge of CME accreditation. This paper is being simultaneously published in European Journal of Neurology and Multiple Sclerosis Journal.[Correction added on 13 February 2018, after online and print publication: (a) The abstract has been updated and a conclusion section in now included; (b) Recommendation 4 and 7 has been amended, and an additional recommendation has been added after the latter]. meta-analysis. The quality of evidence was rated into four categories -very high, high, low and very low À according to the risk of bias. The recommendations with assigned strength (strong, weak) were formulated based on the quality of evidence and the riskÀbenefit balance. Consensus between the panelists was reached by use of the modified nominal group technique. Results: A total of 10 questions have been agreed, encompassing treatment efficacy, response criteria, strategies to address suboptimal response and safety concerns and treatment strategies in MS and pregnancy. The guideline takes into account all disease-modifying drugs approved by the European Medicine Agency at the time of publication. A total of 21 recommendations were agreed by the guideline working group members after three rounds of consensus. Conclusion: The present guideline, which includes descriptions of the evidence together with recommendations, will enable homogeneity of treatment decisions across Europe. © 2018 European Academy of Neurology and European Committee of Treatment of Research in Multiple SclerosisBackground and scope

Neuronal damage in autoimmune neuroinflammation is the correlate for long-term disability in multiple sclerosis (MS) patients. Here, we investigated the role of immune cells in neuronal damage processes in animal models of MS by monitoring experimental autoimmune encephalomyelitis (EAE) by using twophoton microscopy of living anaesthetized mice. In the brainstem, we detected sustained interaction between immune and neuronal cells, particularly during disease peak. Direct interaction of myelin oligodendrocyte glycoprotein (MOG)-specific Th17 and neuronal cells in demyelinating lesions was associated with extensive axonal damage. By combining confocal, electron, and intravital microscopy, we showed that these contacts remarkably resembled immune synapses or kinapses, albeit with the absence of potential T cell receptor engagement. Th17 cells induced severe, localized, and partially reversible fluctuation in neuronal intracellular Ca 2+ concentration as an early sign of neuronal damage. These results highlight the central role of the Th17 cell effector phenotype for neuronal dysfunction in chronic neuroinflammation.