Genotype-Phenotype correlations in multiple sclerosis: HLA genes influence disease severity inferred by 1HMR spectroscopy and MRI measures

A role for vessel-associated extracellular matrix proteins in multiple sclerosis pathology

Multiple sclerosis (MS) is unsurpassed for its clinical and pathological hetherogeneity, but the biological determinants of this variability are unknown. HLA-DRB1*15, the main genetic risk factor for MS, influences the severity and distribution of MS pathology. This study set out to unravel the molecular determinants of the heterogeneity of MS pathology in relation to HLA-DRB1*15 status. Shotgun proteomics from a discovery cohort of MS spinal cord samples segregated by HLA-DRB*15 status revealed overexpression of the extracellular matrix (ECM) proteins, biglycan, decorin, and prolargin in HLA-DRB*15-positive cases, adding to established literature on a role of ECM proteins in MS pathology that has heretofore lacked systematic pathological validation. These findings informed a neuropathological characterisation of these proteins in a large autopsy cohort of 41 MS cases (18 HLA-DRB1*15-positive and 23 HLA-DRB1*15-negative), and seven non-neurological controls on motor cortical, cervical and lumbar spinal cord tissue. Biglycan and decorin demonstrate a striking perivascular expression pattern in controls that is reduced in MS (-36.5%, p = 0.036 and - 24.7%, p = 0.039; respectively) in lesional and non-lesional areas. A concomitant increase in diffuse parenchymal accumulation of biglycan and decorin is seen in MS (p = 0.015 and p = 0.001, respectively), particularly in HLA-DRB1*15-positive cases (p = 0.007 and p = 0.046, respectively). Prolargin shows a faint parenchymal pattern in controls that is markedly increased in MS cases where a perivascular deposition pattern is observed (motor cortex +97.5%, p = 0.001; cervical cord +49.1%, p = 0.016). Our findings point to ECM proteins and the vascular interface playing a central role in MS pathology within and outside the plaque area. As ECM proteins are known potent pro-inflammatory molecules, their parenchymal accumulation may contribute to disease severity. This study brings to light novel factors that may contribute to the heterogeneity of the topographical variation of MS pathology.

Genetic influences on disease course and severity, 30 years after a clinically isolated syndrome

Multiple sclerosis risk has a well-established polygenic component, yet the genetic contribution to disease course and severity remains unclear and difficult to examine. Accurately measuring disease progression requires long-term study of clinical and radiological outcomes with sufficient follow-up duration to confidently confirm disability accrual and multiple sclerosis phenotypes. In this retrospective study, we explore genetic influences on long-term disease course and severity; in a unique cohort of clinically isolated syndrome patients with homogenous 30-year disease duration, deep clinical phenotyping and advanced MRI metrics. Sixty-one clinically isolated syndrome patients [41 female (67%): 20 male (33%)] underwent clinical and MRI assessment at baseline, 1-, 5-, 10-, 14-, 20- and 30-year follow-up (mean age ± standard deviation: 60.9 ± 6.5 years). After 30 years, 29 patients developed relapsing-remitting multiple sclerosis, 15 developed secondary progressive multiple sclerosis and 17 still had a clinically isolated syndrome. Twenty-seven genes were investigated for associations with clinical outcomes [including disease course and Expanded Disability Status Scale (EDSS)] and brain MRI (including white matter lesions, cortical lesions, and brain tissue volumes) at the 30-year follow-up. Genetic associations with changes in EDSS, relapses, white matter lesions and brain atrophy (third ventricular and medullary measurements) over 30 years were assessed using mixed-effects models. HLA-DRB1*1501-positive (n = 26) patients showed faster white matter lesion accrual [+1.96 lesions/year (0.64-3.29), P = 3.8 × 10-3], greater 30-year white matter lesion volumes [+11.60 ml, (5.49-18.29), P = 1.27 × 10-3] and higher annualized relapse rates [+0.06 relapses/year (0.005-0.11), P = 0.031] compared with HLA-DRB1*1501-negative patients (n = 35). PVRL2-positive patients (n = 41) had more cortical lesions (+0.83 [0.08-1.66], P = 0.042), faster EDSS worsening [+0.06 points/year (0.02-0.11), P = 0.010], greater 30-year EDSS [+1.72 (0.49-2.93), P = 0.013; multiple sclerosis cases: +2.60 (1.30-3.87), P = 2.02 × 10-3], and greater risk of secondary progressive multiple sclerosis [odds ratio (OR) = 12.25 (1.15-23.10), P = 0.031] than PVRL2-negative patients (n = 18). In contrast, IRX1-positive (n = 30) patients had preserved 30-year grey matter fraction [+0.76% (0.28-1.29), P = 8.4 × 10-3], lower risk of cortical lesions [OR = 0.22 (0.05-0.99), P = 0.049] and lower 30-year EDSS [-1.35 (-0.87,-3.44), P = 0.026; multiple sclerosis cases: -2.12 (-0.87, -3.44), P = 5.02 × 10-3] than IRX1-negative patients (n = 30). In multiple sclerosis cases, IRX1-positive patients also had slower EDSS worsening [-0.07 points/year (-0.01,-0.13), P = 0.015] and lower risk of secondary progressive multiple sclerosis [OR = 0.19 (0.04-0.92), P = 0.042]. These exploratory findings support diverse genetic influences on pathological mechanisms associated with multiple sclerosis disease course. HLA-DRB1*1501 influenced white matter inflammation and relapses, while IRX1 (protective) and PVRL2 (adverse) were associated with grey matter pathology (cortical lesions and atrophy), long-term disability worsening and the risk of developing secondary progressive multiple sclerosis.

Genome-wide study of longitudinal brain imaging measures of multiple sclerosis progression across six clinical trials

While the genetics of MS risk susceptibility are well-described, and recent progress has been made on the genetics of disease severity, the genetics of disease progression remain elusive. We therefore investigated the genetic determinants of MS progression on longitudinal brain MRI: change in brain volume (BV) and change in T2 lesion volume (T2LV), reflecting progressive tissue loss and increasing disease burden, respectively. We performed genome-wide association studies of change in BV (N = 3401) and change in T2LV (N = 3513) across six randomized clinical trials from Biogen and Roche/Genentech: ADVANCE, ASCEND, DECIDE, OPERA I & II, and ORATORIO. Analyses were adjusted for randomized treatment arm, age, sex, and ancestry. Results were pooled in a meta-analysis, and were evaluated for enrichment of MS risk variants. Variant colocalization and cell-specific expression analyses were performed using published cohorts. The strongest peaks were in PTPRD (rs77321193-C/A, p = 3.9 × 10-7) for BV change, and NEDD4L (rs11398377-GC/G, p = 9.3 × 10-8) for T2LV change. Evidence of colocalization was observed for NEDD4L, and both genes showed increased expression in neuronal and/or glial populations. No association between MS risk variants and MRI outcomes was observed. In this unique, precompetitive industry partnership, we report putative regions of interest in the neurodevelopmental gene PTPRD, and the ubiquitin ligase gene NEDD4L. These findings are distinct from known MS risk genetics, indicating an added role for genetic progression analyses and informing drug discovery.

HLA-DRB1*1501 influences long-term disability progression and tissue damage on MRI in relapse-onset multiple sclerosis

BACKGROUND

Whether genetic factors influence the long-term course of multiple sclerosis (MS) is unresolved.

OBJECTIVE

To determine the influence of HLA-DRB1*1501 on long-term disease course in a homogeneous cohort of clinically isolated syndrome (CIS) patients.

METHODS

One hundred seven patients underwent clinical and MRI assessment at the time of CIS and after 1, 3, 5 and 15 years. HLA-DRB1*1501 status was determined using Sanger sequencing and tagging of the rs3135388 polymorphism. Linear/Poisson mixed-effects models were used to investigate rates of change in EDSS and MRI measures based on HLA-DRB1*1501 status.

RESULTS

HLA-DRB1*1501 -positive (n = 52) patients showed a faster rate of disability worsening compared with the HLA-DRB1*1501 -negative (n = 55) patients (annualised change in EDSS 0.14/year vs. 0.08/year, p < 0.025), and a greater annualised change in T2 lesion volume (adjusted difference 0.45 mL/year, p < 0.025), a higher number of gadolinium-enhancing lesions, and a faster rate of brain (adjusted difference -0.12%/year, p < 0.05) and spinal cord atrophy (adjusted difference -0.22 mm²/year, p < 0.05).

INTERPRETATION

These findings provide evidence that the HLA-DRB1*1501 allele plays a role in MS severity, as measured by long-term disability worsening and a greater extent of inflammatory disease activity and tissue loss. HLA-DRB1*1501 may provide useful information when considering prognosis and treatment decisions in early relapse-onset MS.

Lessons from immunotherapies in multiple sclerosis

The improved understanding of multiple sclerosis (MS) neurobiology alongside the development of novel markers of disease will allow precision medicine to be applied to MS patients, bringing the promise of improved care. Combinations of clinical and paraclinical data are currently used for diagnosis and prognosis. The addition of advanced magnetic resonance imaging and biofluid markers has been strongly encouraged, since classifying patients according to the underlying biology will improve monitoring and treatment strategies. For example, silent progression seems to contribute significantly more than relapses to overall disability accumulation, but currently approved treatments for MS act mainly on neuroinflammation and offer only a partial protection against neurodegeneration. Further research, involving traditional and adaptive trial designs, should strive to halt, repair or protect against central nervous system damage. To personalize new treatments, their selectivity, tolerability, ease of administration, and safety must be considered, while to personalize treatment approaches, patient preferences, risk-aversion, and lifestyle must be factored in, and patient feedback used to indicate real-world treatment efficacy. The use of biosensors and machine-learning approaches to integrate biological, anatomical, and physiological parameters will take personalized medicine a step closer toward the patient's virtual twin, in which treatments can be tried before they are applied.

Risk HLA Variants Affect the T-Cell Repertoire in Multiple Sclerosis

BACKGROUND AND OBJECTIVES

The major histocompatibility complex (MHC) locus has a predominant role in the genetic predisposition to multiple sclerosis (MS), with 32 associations found to be involved. We aimed to investigate the impact of MHC MS-risk alleles on T-cell repertoire in patients with MS.

METHODS

We studied 161 untreated patients with relapsing-remitting MS for whom Class I and II human leukocyte antigen (HLA) alleles were inferred from whole-genome genotyping data, and T-cell receptor (TCR) CDR3 sequences were obtained through next-generation sequencing. T-cell repertoire features including diversity, public clones, and architecture were evaluated.

RESULTS

We identified 5 MS-risk loci associated with TCR diversity: HLA-DRB1*15:01 (7.65 × 10^-3), rs9271366 (1.96 × 10^-3), rs766848979 A (1.89 × 10^-2), rs9277626 (2.95 × 10^-2), and rs11751659 (1.92 × 10^-2), with evidence of expanded clonotypes in carriers of risk alleles. Moreover, HLA-DRB1*15:01 (4.99 × 10^-3), rs9271366 (6.54 × 10^-3), rs1049079 C (4.37 × 10^-2), AA DQΒ1 position -5 L (1.05 × 10^-3), and AA DQΒ1 position 221 Q (9.39 × 10^-4) showed an association with the CDR3 aminoacidic sequence architecture, suggesting an impact on the antigen recognition breadth as well. Evaluating the sharing of clones across MS-risk allele carrier individuals revealed the presence of highly shared clonotypes predicted to target viral antigens, including Epstein-Barr virus.

DISCUSSION

Our study supports the association between MHC-risk alleles and macrofeatures of the T-cell repertoire in the context of MS. Further studies are needed to understand the underlying molecular mechanisms.

Exploring the Association of HLA Genetic Risk Burden on Thalamic and Hippocampal Atrophy in Multiple Sclerosis Patients

Multiple sclerosis (MS) is a complex disease of the central nervous system for which human leukocyte antigen (HLA) alleles are major contributors to susceptibility. Several investigations have focused on the relationship between HLA and clinical parameters, while few studies have evaluated its correlation with brain magnetic resonance imaging (MRI) measures. We investigated the association between the HLA genetic burden (HLAGB), originating from the most updated HLA alleles associated with MS, and neuroimaging endophenotypes, with a specific focus on brain atrophy metrics. A monocentric Italian cohort of 334 MS patients with imputed HLA alleles and cross-sectional volumetric measures of white matter (WM), gray matter (GM), hippocampus, thalamus and T2-hyperintense lesions was investigated. Linear regression models with covariate adjustment were fitted for each metric. We detected no effect of HLAGB on WM and GM volumes. Interestingly, we found a marginal correlation between higher HLAGB and lower hippocampal volume (β = -0.142, p = 0.063) and a nominal association between higher HLAGB and lower thalamic volume (β = -0.299, p = 0.047). No association was found with T2 lesion volumes. The putative impact of higher HLAGB on hippocampus and thalamus suggests, if replicated in independent cohorts, a possible cumulative contribution of HLA risk loci on brain volumetric traits linked to clinical deficits in MS.

Modeling neurodegenerative disorders in zebrafish

Neurodegeneration is a major cause of Alzheimer's, Parkinson's, Huntington's, multiple and amyotrophic lateral sclerosis, pontocerebellar hypoplasia, dementia and other related brain disorders. Their complex pathogenesis commonly includes genetic and neurochemical deficits, misfolded protein toxicity, demyelination, apoptosis and mitochondrial dysfunctions. Albeit differing in specific underlying mechanisms, neurodegenerative disorders typically display evolutionarily conserved mechanisms across taxa. Here, we review the role of zebrafish models in recapitulating major human and rodent neurodegenerative conditions, demonstrating this species as a highly relevant experimental model for research on neurodegenerative diseases, and discussing how these fish models can further clarify the underlying genetic, neurochemical, neuroanatomical and behavioral pathogenic mechanisms.

Symptom Interconnectivity in Multiple Sclerosis: A Narrative Review of Potential Underlying Biological Disease Processes

Introduction

Fatigue, cognitive impairment, depression, and pain are highly prevalent symptoms in multiple sclerosis (MS). These often co-occur and may be explained by a common etiology. By reviewing existing literature, we aimed to identify potential underlying biological processes implicated in the interconnectivity between these symptoms.

Methods

A literature search was conducted to identify articles reporting research into the biological mechanisms responsible for the manifestation of fatigue, cognitive impairment, depression, and pain in MS. PubMed was used to search for articles published from July 2011 to July 2021. We reviewed and assessed findings from the literature to identify biological processes common to the symptoms of interest.

Results

Of 693 articles identified from the search, 252 were selected following screening of titles and abstracts and assessing reference lists of review articles. Four biological processes linked with two or more of the symptoms of interest were frequently identified from the literature: (1) direct neuroanatomical changes to brain regions linked with symptoms of interest (e.g., thalamic injury associated with cognitive impairment, fatigue, and depression), (2) pro-inflammatory cytokines associated with so-called ‘sickness behavior,’ including manifestation of fatigue, transient cognitive impairment, depression, and pain, (3) dysregulation of monoaminergic pathways leading to depressive symptoms and fatigue, and (4) hyperactivity of the hypothalamic–pituitary-adrenal (HPA) axis as a result of pro-inflammatory cytokines promoting the release of brain noradrenaline, serotonin, and tryptophan, which is associated with symptoms of depression and cognitive impairment.

Conclusion

The co-occurrence of fatigue, cognitive impairment, depression, and pain in MS appears to be associated with a common set of etiological factors, namely neuroanatomical changes, pro-inflammatory cytokines, dysregulation of monoaminergic pathways, and a hyperactive HPA axis. This association of symptoms and biological processes has important implications for disease management strategies and, eventually, could help find a common therapeutic pathway that will impact both inflammation and neuroprotection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-022-00368-2.

HLA-DQA1*04:01 is related to a higher multiple sclerosis lesion load on T2/Flair MRI sequences

BACKGROUND

The genetic predisposition to multiple sclerosis (MS) is associated with HLA alleles, especially HLA-DRB1*15:01.

OBJECTIVE

To identify associations between findings in magnetic resonance imaging (MRI) and genetic features in a Brazilian cohort of patients with MS.

METHODS

We retrospectively studied data from 95 consecutive patients with MS. Two independent observers who were blinded to the clinical data identified black holes and enhanced lesions on T1 MRI sequences, and counted and measured contrast-enhanced lesions on T2 and Flair (fluid attenuation inversion recovery) sequences. Cases were classified according to lesion size, number, and volume. The HLA-DRB1, HLA-DQB1, and HLA-DQA1 alleles, and the rs4774, rs3087456, rs6897932, rs731236, and rs1033182 single nucleotide polymorphisms were identified by polymerase chain reaction amplification with sequence-specific primers using the One Lambda Inc. Kit, Canoga Park, CA, USA.

RESULTS

Patients with the HLA-DQA1*04:01 allele had lesion load (adjusted for age, sex, and MS duration) above median compared with patients with other HLA-DQA1 alleles (p=0.02). There were no differences among all the other HLA alleles and single nucleotide polymorphisms and lesion load.

CONCLUSIONS

The correlation of the HLA-DQA1*04:01 allele with a higher lesion load on T2/Flair MRI sequences suggests that the presence of this allele is associated with the risk of greater MS severity.

Genetic, Environmental and Lifestyle Determinants of Accelerated Telomere Attrition as Contributors to Risk and Severity of Multiple Sclerosis

Telomeres are protective structures at the ends of linear chromosomes. Shortened telomere lengths (TL) are an indicator of premature biological aging and have been associated with a wide spectrum of disorders, including multiple sclerosis (MS). MS is a chronic inflammatory, demyelinating and neurodegenerative disease of the central nervous system. The exact cause of MS is still unclear. Here, we provide an overview of genetic, environmental and lifestyle factors that have been described to influence TL and to contribute to susceptibility to MS and possibly disease severity. We show that several early-life factors are linked to both reduced TL and higher risk of MS, e.g., adolescent obesity, lack of physical activity, smoking and vitamin D deficiency. This suggests that the mechanisms underlying the disease are connected to cellular aging and senescence promoted by increased inflammation and oxidative stress. Additional prospective research is needed to clearly define the extent to which lifestyle changes can slow down disease progression and prevent accelerated telomere loss in individual patients. It is also important to further elucidate the interactions between shared determinants of TL and MS. In future, cell type-specific studies and advanced TL measurement methods could help to better understand how telomeres may be causally involved in disease processes and to uncover novel opportunities for improved biomarkers and therapeutic interventions in MS.

Chronic Neurological Disorders: Genetic and Epigenetic Markers for Monitoring of Pharmacotherapy

Introduction

Chronic neurological diseases are a major cause of mortality and morbidity in the world. With increasing life expectancy in the developing world, the incidence and prevalence of these diseases are predicted to rise even further. This has also contributed to an increase in disability-adjusted life years (DALYs) for noncommunicable diseases. Treatment for such diseases also poses a challenge with multiple genetic and epigenetic factors leading to a varied outcome. Personalization of treatment is one way that treatment outcome/prognosis of disease can be improved, and pharmacogenomics plays a significant role in this context.

Methodology

This article reviewed the evidence pertaining to the association of genetic and epigenetic markers with major neurological disorders like multiple sclerosis (MS), Alzheimer's disease (AD), and Parkinson's disease (PD), which are a major source of burden among neurological disorders. Types of studies included are peer-reviewed original research articles from the PubMed database (1999-2018).

Results

This study compiled data regarding specific genetic and epigenetic markers with a significant correlation between the clinical diagnosis of the disease and prognosis of therapy from 65 studies. In a single platform, this review highlights the clues to some vital questions, such as why interferon beta (IFN-β) therapy fails to improve symptoms in all MS patients? why cholinesterase inhibitors fail to improve cognitive impairment in a subset of people suffering from AD? or why some individuals on levodopa (L-DOPA) for PD suffer from side-effects ranging from dyskinesia to hallucination while others do not?

Conclusion

This article summarizes the genetic and epigenetic factors that may either require monitoring or help in deciding future pharmacotherapy in a patient suffering from MS, AD, and PD. As the health care system develops and reaches newer heights, we expect more and more of these biomarkers to be used as pharmacotherapeutic outcome indicators.

HLA genotype-clinical phenotype correlations in multiple sclerosis and neuromyelitis optica spectrum disorders based on Japan MS/NMOSD Biobank data

HLA genotype-clinical phenotype correlations are not established for multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). We studied HLA-DRB1/DPB1 genotype–phenotype correlations in 528 MS and 165 NMOSD cases using Japan MS/NMOSD Biobank materials. HLA-DRB1*04:05, DRB1*15:01 and DPB1*03:01 correlated with MS susceptibility and DRB1*01:01, DRB1*09:01, DRB1*13:02 and DPB1*04:01 were protective against MS. HLA-DRB1*15:01 was associated with increased optic neuritis and cerebellar involvement and worsened visual and pyramidal functional scale (FS) scores, resulting in higher progression index values. HLA-DRB1*04:05 was associated with younger onset age, high visual FS scores, and a high tendency to develop optic neuritis. HLA-DPB1*03:01 increased brainstem and cerebellar FS scores. By contrast, HLA-DRB1*01:01 decreased spinal cord involvement and sensory FS scores, HLA-DRB1*09:01 decreased annualized relapse rate, brainstem involvement and bowel and bladder FS scores, and HLA-DRB1*13:02 decreased spinal cord and brainstem involvement. In NMOSD, HLA-DRB1*08:02 and DPB1*05:01 were associated with susceptibility and DRB1*09:01 was protective. Multivariable analysis revealed old onset age, long disease duration, and many relapses as independent disability risks in both MS and NMOSD, and HLA-DRB1*15:01 as an independent risk only in MS. Therefore, both susceptibility and protective alleles can influence the clinical manifestations in MS, while such genotype–phenotype correlations are unclear in NMOSD.

Association of Vitamin D Metabolism Gene Polymorphisms with Autoimmunity: Evidence in Population Genetic Studies

A high prevalence of vitamin D (calcidiol) serum deficiency has been described in several autoimmune diseases, including multiple sclerosis (MS), rheumatoid arthritis (AR), and systemic lupus erythematosus (SLE). Vitamin D is a potent immunonutrient that through its main metabolite calcitriol, regulates the immunomodulation of macrophages, dendritic cells, T and B lymphocytes, which express the vitamin D receptor (VDR), and they produce and respond to calcitriol. Genetic association studies have shown that up to 65% of vitamin D serum variance may be explained due to genetic background. The 90% of genetic variability takes place in the form of single nucleotide polymorphisms (SNPs), and SNPs in genes related to vitamin D metabolism have been linked to influence the calcidiol serum levels, such as in the vitamin D binding protein (VDBP; rs2282679 GC), 25-hydroxylase (rs10751657 CYP2R1), 1α-hydroxylase (rs10877012, CYP27B1) and the vitamin D receptor (FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232), and TaqI (rs731236) VDR). Therefore, the aim of this comprehensive literature review was to discuss the current findings of functional SNPs in GC, CYP2R1, CYP27B1, and VDR associated to genetic risk, and the most common clinical features of MS, RA, and SLE.

Association of Chronic Active Multiple Sclerosis Lesions With Disability In Vivo

Importance

In multiple sclerosis (MS), chronic active lesions, which previously could only be detected at autopsy, can now be identified on susceptibility-based magnetic resonance imaging (MRI) in vivo as non-gadolinium-enhancing lesions with paramagnetic rims. Pathologically, they feature smoldering inflammatory demyelination at the edge, remyelination failure, and axonal degeneration. To our knowledge, the prospect of long-term in vivo monitoring makes it possible for the first time to determine their contribution to disability and value as a treatment target.

Objective

To assess whether rim lesions are associated with patient disability and long-term lesion outcomes.

Design, Setting, Participants

We performed 3 studies at the National Institutes of Health Clinical Center: (1) a prospective clinical/radiological cohort of 209 patients with MS (diagnosis according to the 2010 McDonald revised MS criteria, age ≥18 years, with 7-T or 3-T susceptibility-based brain MRI results) who were enrolled from January 2012 to March 2018 (of 209, 17 patients [8%] were excluded because of uninterpretable MRI scans); (2) a radiological/pathological analysis of expanding lesions featuring rims; and (3) a retrospective longitudinal radiological study assessing long-term lesion evolution in 23 patients with MS with yearly MRI scans for 10 years or more (earliest scan, 1992).

Main Outcomes and Measures

(1) Identification of chronic rim lesions on 7-T or 3-T susceptibility-based brain MRI in 192 patients with MS and the association of rim counts with clinical disability (primary analysis) and brain volume changes (exploratory analysis). (2) Pathological characterization of 10 expanding lesions from an adult with progressive MS who came to autopsy after 7 years of receiving serial in vivo MRI scans. (3) Evaluation of annual lesion volume change (primary analysis) and T1 times (exploratory analysis) in 27 rim lesions vs 27 rimless lesions.

Results

Of 209 participants, 104 (50%) were women and 32 (15%) were African American. One hundred seventeen patients (56%) had at least 1 rim lesion regardless of prior or ongoing treatment. Further, 84 patients (40%) had no rims (mean [SD] age, 47 [14] years), 66 (32%) had 1 to 3 rims (mean [SD] age, 47 [11] years), and 42 (20%) had 4 rims or more (mean [SD] age, 44 [11] years). Individuals with 4 rim lesions or more reached motor and cognitive disability at an earlier age. Normalized volumes of brain, white matter, and basal ganglia were lower in those with rim lesions. Whereas rimless lesions shrank over time (-3.6%/year), rim lesions were stable in size or expanded (2.2%/year; P < .001). Rim lesions had longer T1 times, suggesting more tissue destruction, than rimless lesions. On histopathological analysis, all 10 rim lesions that expanded in vivo had chronic active inflammation.

Conclusions and Relevance

Chronic active lesions are common, are associated with more aggressive disease, exert ongoing tissue damage, and occur even in individuals treated with effective disease-modifying therapies. These results prompt the planning of MRI-based clinical trials aimed at treating perilesional chronic inflammation in MS.

Artificial Intelligence-Based Clinical Decision Support Systems Using Advanced Medical Imaging and Radiomics

Artificial intelligence (AI) is poised to make a veritable impact in medicine. Clinical decision support (CDS) is an important area where AI can augment the clinician's capability to collect, understand and make inferences on an overwhelming volume of patient data to reach the optimal clinical decision. Advancements in medical image analysis, such as Radiomics, and data computation, such as machine learning, have expanded our understanding of disease processes and their management. In this article, we review the most relevant concepts of AI as applicable to advanced imaging-based clinical decision support systems.

Aggressive multiple sclerosis (1): Towards a definition of the phenotype

While the major phenotypes of multiple sclerosis (MS) and relapsing-remitting, primary and secondary progressive MS have been well characterized, a subgroup of patients with an active, aggressive disease course and rapid disability accumulation remains difficult to define and there is no consensus about their management and treatment. The current lack of an accepted definition and treatment guidelines for aggressive MS triggered a 2018 focused workshop of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) on aggressive MS. The aim of the workshop was to discuss approaches on how to describe and define the disease phenotype and its treatments. Unfortunately, it was not possible to come to consensus on a definition because of unavailable data correlating severe disease with imaging and molecular biomarkers. However, the workshop highlighted the need for future research needed to define this disease subtype while also focusing on its treatment and management. Here, we review previous attempts to define aggressive MS and present characteristics that might, with additional research, eventually help characterize it. A companion paper summarizes data regarding treatment and management.

An Intergenic rs9275596 Polymorphism on Chr. 6p21 Is Associated with Multiple Sclerosis in Latvians

Background and objectives: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system, leading to demyelination of neurons and potentially debilitating physical and mental symptoms. The disease is more prevalent in women than in men. The major histocompatibility complex (MHC) region has been identified as a major genetic determinant for autoimmune diseases, and its role in some neurological disorders including MS was evaluated. An intergenic single-nucleotide polymorphism (SNP), rs9275596, located between the HLA-DQB1 and HLA-DQA2 genes, is in significant association with various autoimmune diseases according to genome-wide association studies (GWASs). A cumulative effect of this SNP with other polymorphisms from this region was revealed. The aim of the study was to verify the data on rs9275596 association in multiple sclerosis in a case/control study of the Latvian population and to evaluate eventual functional significance of allele substitutions. Materials and Methods: rs9275596 (chr6:32713854; GRCh38.p12) was genotyped in 273 MS patients and 208 controls on main and sex-specific associations. Eventual functional significance of allele substitutions was evaluated in silico using publicly available tools. Results: The rs9275596 rare alleles were identified as a disease susceptibility factor in association with the MS main group and in affected females (p < 0.001 and p < 0.01, respectively). Risk factor genotypes with rare alleles included were associated with the MS common cohort (p < 0.002) and female cohort (odds ratio, OR = 2.24) and were identified as disease susceptible in males (OR = 2.41). It was shown that structural changes of rs9275596 affect the secondary structure of DNA. Functional significance of allele substitutions was evaluated on the eventual sequence affinity to transcription factors (TFs) and splicing signals similarity. A possible impact of the particular polymorphisms on the transcription and splicing efficiency is discussed. Conclusions: Our results suggest susceptibility of rs9275596 to multiple sclerosis in Latvians.

Central nervous system-specific antinuclear antibodies in patients with multiple sclerosis

BACKGROUND

Nuclear antigen released from central nervous system (CNS) cells undergoing destruction may induce production of antinuclear antibodies (ANA). We characterized the CNS-specific production of ANA in multiple sclerosis (MS).

METHODS

We assessed CNS-ANA binding to mouse cerebellar cell nuclei by immunofluorescence assay (IFA) with sera from 104 MS patients (91 relapsing-remitting; 13 secondary progressive), 30 patients with neuromyelitis optica spectrum disorders (NMOSD), and 30 healthy controls (HCs). Conventional ANA (cANA) was detected by IFA using human epithelial type-2 cells. CNS-ANA-positive cANA-negative patients were termed CNS-specific ANA-positive. Western blotting (WB) was performed using mouse cerebellar nuclear fractions.

RESULTS

CNS-specific ANA were more frequent in MS than in NMOSD patients or HCs (13.5% vs 0% for both comparisons, both p < .05) and were associated with HLA-DRB1*15:01 (p = .0174). WB revealed a common 55 kDa band in seven MS patients. Compared with CNS-specific ANA-negative MS patients, those with 55 kDa band-immunoreactive CNS-specific ANA showed a higher frequency of secondary progressive MS (42.9% vs 10.0%, p = .0387) and greater Expanded Disability Status Scale scores (4.50 ± 2.02 vs 2.92 ± 2.27, p = .0506).

CONCLUSIONS

The CNS-specific ANA was more frequently detected in MS patients than NMOSD patients or HCs. 55 kDa band-reactive CNS-specific ANA may reflect clinical disease progression in MS.

Biomarkers of Multiple Sclerosis

The search for an ideal multiple sclerosis biomarker with good diagnostic value, prognostic reference and an impact on clinical outcome has yet to be realized and is still ongoing. The aim of this review is to establish an overview of the frequent biomarkers for multiple sclerosis that exist to date. The review summarizes the results obtained from electronic databases, as well as thorough manual searches. In this review the sources and methods of biomarkers extraction are described; in addition to the description of each biomarker, determination of the prognostic, diagnostic, disease monitoring and treatment response values besides clinical impact they might possess. We divided the biomarkers into three categories according to the achievement method: laboratory markers, genetic-immunogenetic markers and imaging markers. We have found two biomarkers at the time being considered the gold standard for MS diagnostics. Unfortunately, there does not exist a single solitary marker being able to present reliable diagnostic value, prognostic value, high sensitivity and specificity as well as clinical impact. We need more studies to find the best biomarker for MS.

Recent advances in understanding multiple sclerosis

Emerging data point to important contributions of both autoimmune inflammation and progressive degeneration in the pathophysiology of multiple sclerosis (MS). Unfortunately, after decades of intensive investigation, the fundamental cause remains unknown. A large body of research on the immunobiology of MS has resulted in a variety of anti-inflammatory therapies that are highly effective at reducing brain inflammation and clinical/radiological relapses. However, despite potent suppression of inflammation, benefit in the more important and disabling progressive phase is extremely limited; thus, progressive MS has emerged as the greatest challenge for the MS research and clinical communities. Data obtained over the years point to a complex interplay between environment (e.g., the near-absolute requirement of Epstein-Barr virus exposure), immunogenetics (strong associations with a large number of immune genes), and an ever more convincing role of an underlying degenerative process resulting in demyelination (in both white and grey matter regions), axonal and neuro-synaptic injury, and a persistent innate inflammatory response with a seemingly diminishing role of T cell-mediated autoimmunity as the disease progresses. Together, these observations point toward a primary degenerative process, one whose cause remains unknown but one that entrains a nearly ubiquitous secondary autoimmune response, as a likely sequence of events underpinning this disease. Here, we briefly review what is known about the potential pathophysiological mechanisms, focus on progressive MS, and discuss the two main hypotheses of MS pathogenesis that are the topic of vigorous debate in the field: whether primary autoimmunity or degeneration lies at the foundation. Unravelling this controversy will be critically important for developing effective new therapies for the most disabling later phases of this disease.

Human Leukocyte Antigen Genotype as a Marker of Multiple Sclerosis Prognosis

OBJECTIVE

In a previous pilot monocentric study, we investigated the relation between human leukocyte antigen (HLA) genotype and multiple sclerosis (MS) disease progression over 2 years. HLA-A*02 allele was correlated with better outcomes, whereas HLA-B*07 and HLA-B*44 were correlated with worse outcomes. The objective of this extension study was to further investigate the possible association of HLA genotype with disease status and progression in MS as measured by sensitive and complex clinical and imaging parameters.

METHODS

Hundred and forty-six MS patients underwent HLA typing. Over a 4-year period of follow-up, we performed three clinical and magnetic resonance imaging (MRI) assessments per patient, which respectively included Expanded Disability Status Scale, Multiple Sclerosis Severity Scale, Timed-25-Foot-Walk, 9-Hole Peg Test, Symbol Digit Modalities Test, Brief Visual Memory Test, California Verbal Learning Test-II, and whole-brain atrophy, fluid-attenuated inversion recovery (FLAIR) lesion volume change and number of new FLAIR lesions using icobrain. We then compared the clinical and MRI outcomes between predefined HLA patient groups.

RESULTS

Results of this larger study with a longer follow-up are in line with what we have previously shown. HLA-A*02 allele is associated with potentially better MS outcomes, whereas HLA-B*07, HLA-B*44, HLA-B*08, and HLA-DQB1*06 with a potential negative effect. Results for HLA-DRB1*15 are inconclusive.

CONCLUSION

In the era of MS treatment abundance, HLA genotype might serve as an early biomarker for MS outcomes to inform individualized treatment decisions.

Quantifying the Metabolic Signature of Multiple Sclerosis by in vivo Proton Magnetic Resonance Spectroscopy: Current Challenges and Future Outlook in the Translation From Proton Signal to Diagnostic Biomarker

Proton magnetic resonance spectroscopy (¹H-MRS) offers a growing variety of methods for querying potential diagnostic biomarkers of multiple sclerosis in living central nervous system tissue. For the past three decades, ¹H-MRS has enabled the acquisition of a rich dataset suggestive of numerous metabolic alterations in lesions, normal-appearing white matter, gray matter, and spinal cord of individuals with multiple sclerosis, but this body of information is not free of seeming internal contradiction. The use of ¹H-MRS signals as diagnostic biomarkers depends on reproducible and generalizable sensitivity and specificity to disease state that can be confounded by a multitude of influences, including experiment group classification and demographics; acquisition sequence; spectral quality and quantifiability; the contribution of macromolecules and lipids to the spectroscopic baseline; spectral quantification pipeline; voxel tissue and lesion composition; T₁ and T₂ relaxation; B₁ field characteristics; and other features of study design, spectral acquisition and processing, and metabolite quantification about which the experimenter may possess imperfect or incomplete information. The direct comparison of ¹H-MRS data from individuals with and without multiple sclerosis poses a special challenge in this regard, as several lines of evidence suggest that experimental cohorts may differ significantly in some of these parameters. We review the existing findings of in vivo¹H-MRS on central nervous system metabolic abnormalities in multiple sclerosis and its subtypes within the context of study design, spectral acquisition and processing, and metabolite quantification and offer an outlook on technical considerations, including the growing use of machine learning, by future investigations into diagnostic biomarkers of multiple sclerosis measurable by ¹H-MRS.

Precision medicine for multiple sclerosis promotes preventative medicine

Multiple sclerosis (MS) is a chronic, lifelong disease, currently without a cure that is responsible for significant neurological injury in young adults. Precision medicine for MS aims to provide a more exacting and refined approach toward management by providing recommendations based on disease subtype, clinical status, existing radiological data, para-clinical data, and other biological markers. To achieve better outcomes, the three stages of care-diagnosis, treatment, and management-should be optimized. However, as the temporal profile of disease behavior is highly variable in MS, and unlike outcomes from other chronic conditions (i.e., hypertension, diabetes mellitus, etc.), should precision medicine for MS be one that focuses more on disease prevention and lifestyle modifications beyond recommendations for the use of disease-modifying therapies? As scientific advancements continue within the field of neuroimmunology, and until reliable biomarkers that predict disease outcomes are available, success may be better achieved by focusing on modifiable factors to reduce future disability.

Multiple sclerosis genetics

A broad scientific consensus has emerged linking multiple sclerosis (MS) risk to multiple independent and interacting DNA variants that are relatively frequent in the population and act in concert with environmental exposures. The multifactorial, polygenic model of heritability provided the rationale and impetus to pursue genome-wide association studies (GWAS), which have been highly successful in uncovering genetic variants influencing susceptibility. Over 200 loci have been firmly associated with MS susceptibility. The main association signal genome-wide maps to the major histocompatibility complex ( MHC) gene cluster in chromosome 6p21. This association has been observed across all populations studied. However, a significant proportion of MS heritability remains unexplained. Decoding the genetics of MS represents a long-standing and important research goal in this disease, as the demonstration of even modest functional genomic effects on risk or the course of MS is likely to reveal fundamental disease mechanisms and possibly yield new therapeutic opportunities.

Biomarkers in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic neurodegenerative autoimmune disease with a complex clinical course characterized by inflammation, demyelination, and axonal degeneration. Diagnosis of MS most commonly includes finding lesions in at least two separate areas of the central nervous system (CNS), including the brain, spinal cord, and optic nerves. In recent years, there has been a remarkable increase in the number of available treatments for MS. An optimal treatment is usually based on a personalized approach determined by an individual patient's prognosis and treatment risks. Biomarkers that can predict disability progression, monitor ongoing disease activity, and assess treatment response are integral in making important decisions regarding MS treatment. This review describes MS biomarkers that are currently being used in clinical practice; it also reviews and consolidates published findings from clinically relevant potential MS biomarkers in recent years. The work also discusses the challenges of validating and application of biomarkers in MS clinical practice.

Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disorder. Although all MS patients initially show a relapsing-remitting course, 20-50% subsequently enter a chronic progressive course at 10-20 years after onset that greatly influences their activities of daily living. There are 2.5 million MS patients worldwide with large regional and racial differences. In particular, there are many MS patients among Caucasians living in Europe, while the disease is relatively rare in Asians and Africans.Although MS is regarded as an autoimmune disease, many factors such as genetic background, environmental factors, and sex are involved in its pathogenesis. While the immunological mechanisms remain to be fully elucidated, invasion of autoreactive T cells into the central nervous system (CNS) tissue is considered the first step of the disease. These T cells react with myelin antigens and initiate demyelination of the CNS by activating cytotoxic T cells, macrophages, and B cells through the release of inflammatory cytokines. As a treatment option, disease-modifying therapies have recently been developed to prevent the recurrence of MS in addition to conventional treatment with corticosteroids for acute relapse. However, there are still few effective treatments for the chronic progressive phase, and it is thus imperative to decipher the mechanism for chronic progression.

Body mass index, but not vitamin D status, is associated with brain volume change in MS

OBJECTIVE

To determine whether body mass index (BMI) or vitamin D status is associated with MRI measures of neurodegeneration in a cohort of individuals with relapsing-remitting multiple sclerosis (RRMS) or clinically isolated syndrome (CIS).

METHODS

Expression, Proteomics, Imaging, Clinical (EPIC) is a longitudinal multiple sclerosis (MS) cohort study at the University of California, San Francisco. Participants had clinical evaluations, brain MRI, and blood draws annually. We evaluated patients with CIS or RRMS at baseline. In multivariate repeated-measures analyses adjusted for age, sex, ethnicity, smoking status, and use of MS treatments, annual 25-hydroxyvitamin D levels and BMI were evaluated for their association with subsequent brain volumes (normalized gray matter [nGMV], brain parenchymal [nBPV], and white matter volumes, as determined by Structural Image Evaluation using Normalization of Atrophy-X).

RESULTS

Among 469 participants, each 1-kg/m2 higher BMI was independently associated with reduced nGMV in multivariate models (-1.1 mL, 95% confidence interval [CI] -1.8 to -0.5, p = 0.001). BMI was likewise independently associated with nBPV (nBPV per 1-kg/m2 greater BMI: -1.1 mL, 95% CI -2.1 to -0.05, p = 0.039). Vitamin D levels did not appear to be meaningfully associated with brain volumes.

CONCLUSIONS

Higher BMI appears to be associated with greater reductions in nGMV and nBPV, which is relevant because, in particular, nGMV loss portends greater longer-term disability. Because obesity is modifiable, further studies should explore these relationships in detail, and evaluating the effect of reducing BMI on imaging and clinical outcomes in MS may be warranted.

Anti-Myelin Oligodendrocyte Glycoprotein and Human Leukocyte Antigens as Markers in Pediatric and Adolescent Multiple Sclerosis: on Diagnosis, Clinical Phenotypes, and Therapeutic Responses

Early-onset (pediatric and adolescent) multiple sclerosis (MS) is a well-established demyelinating disease that accounts for approximately 3-5% of all MS cases. Thus, identifying potential biomarkers that can reflect the pathogenic mechanisms, disease course and prognosis, and therapeutic response in such patients is of paramount importance. Myelin oligodendrocyte glycoprotein (MOG) has been regarded as a putative autoantigen and autoantibody target in patients with demyelinating diseases for almost three decades. However, recent studies have suggested that antibodies against MOG represent a distinct clinical entity of dominantly humoral profile, with a range of clinical phenotypes closely related to the age of onset, specific patterns of disease course, and responses to treatment. Furthermore, the major histocompatibility complex (MHC)—which has been regarded as the “gold standard” for attributing genetic burden in adult MS since the early 1970s—has also emerged as the primary genetic locus in early-onset MS, particularly with regard to the human leukocyte antigen (HLA) alleles DRB1⁎1501 and DRB1⁎0401. Recent studies have investigated the potential interactions among HLA, MOG, and environmental factors, demonstrating that early-onset MS is characterized by genetic, immunogenetic, immunological, and familial trait correlations. In this paper, we review recent evidence regarding HLA-genotyping and MOG antibodies—the two most important candidate biomarkers for early-onset MS—as well as their potential application in the diagnosis and treatment of MS.

The HLA-DRB1 and HLA-DQB1 alleles are associated with multiple sclerosis disability progression in Slovak population

OBJECTIVE

The aim of our present study was to analyse the association of HLA-DRB1 and -DQB1 alleles and genotypes with Multiple Sclerosis (MS) disability progression in a cohort of Central European Slovak population.

METHODS

The allele and genotype variants were analyzed in 282 non-related MS patients. Rate of disease disability progression was evaluated using EDSS score in the 5^th, 7^th, 10^th, and 15^th year of disease duration, time to reach EDSS score 3 and 5, and MSSS score. Genotyping was performed by polymerase chain reaction with sequence-specific primers.

RESULTS

We found that carriers of homozygous genotype for alleles DRB1*15 and DQB1*03 reached EDSS score 3 significantly earlier than non-carriers of these alleles (p = 0.0172; p = 0.00183, respectively). Genotype DQB1*03/03 carriage was also associated with significantly reduced time to reach EDSS score 5 (p = 0.00316). Lower EDSS score in the 5^th year of disease duration was found in carriers of DRB1*07 allele (p _cor = 0.028). When MSSS score was used, genotype DRB1*15/15 was found to be less frequent in slow progressing MS patients, when compared to MS patients with mid-rate and rapid disease disability progression (p _cor = 0.0305).

DISCUSSION

We showed for the first time that HLA-DRB1 and -DQB1 genotypes are genetic markers associated with disability progression in Slovak MS patients. Genotypes DRB1*15/15 and DQB1*03/*03 were identified as short-term clinical negative prognostic factors, while allele DRB1*07 carriage appeared to be a positive prognostic marker of better MS outcome.

The immunogenetics of neurological disease

Genes encoding antigen-presenting molecules within the human major histocompatibility complex (MHC) account for the highest component of genetic risk for many neurological diseases, such as multiple sclerosis, neuromyelitis optica, Parkinson's disease, Alzheimer's disease, schizophrenia, myasthenia gravis and amyotrophic lateral sclerosis. Myriad genetic, immunological and environmental factors may contribute to an individual's susceptibility to neurological disease. Here, we review and discuss the decades long research on the influence of genetic variation at the MHC locus and the role of immunogenetic killer cell immunoglobulin-like receptor (KIR) loci in neurological diseases, including multiple sclerosis, neuromyelitis optica, Parkinson's disease, Alzheimer's disease, schizophrenia, myasthenia gravis and amyotrophic lateral sclerosis. The findings of immunogenetic association studies are consistent with a polygenic model of inheritance in the heterogeneous and multifactorial nature of complex traits in various neurological diseases. Future investigation is highly recommended to evaluate both coding and non-coding variation in immunogenetic loci using high-throughput high-resolution next-generation sequencing technologies in diverse ethnic groups to fully appreciate their role in neurological diseases.

Association of smoking but not HLA-DRB1*15:01, APOE or body mass index with brain atrophy in early multiple sclerosis

BACKGROUND

The course of multiple sclerosis (MS) shows substantial inter-individual variability. The underlying determinants of disease severity likely involve genetic and environmental factors.

OBJECTIVE

The aim of this study was to assess the impact of APOE and HLA polymorphisms as well as smoking and body mass index (BMI) in the very early MS course.

METHODS

Untreated patients ( n = 263) with a recent diagnosis of relapsing-remitting (RR) MS or clinically isolated syndrome underwent standardized magnetic resonance imaging (MRI). Genotyping was performed for single-nucleotide polymorphisms (SNPs) rs3135388 tagging the HLA-DRB1*15:01 haplotype and rs7412 (Ɛ2) and rs429358 (Ɛ4) in APOE. Linear regression analyses were applied based on the three SNPs, smoking and BMI as exposures and MRI surrogate markers for disease severity as outcomes.

RESULTS

Current smoking was associated with reduced gray matter fraction, lower brain parenchymal fraction and increased cerebrospinal fluid fraction in comparison to non-smoking, whereas no effect was observed on white matter fraction. BMI and the SNPs in HLA and APOE were not associated with structural MRI parameters.

CONCLUSIONS

Smoking may have an unfavorable effect on the gray matter fraction as a potential measure of MS severity already in early MS. These findings may impact patients' counseling upon initial diagnosis of MS.

Multiple sclerosis and HLA genotypes: A possible influence on brain atrophy

BACKGROUND

The strongest genetic determinant for multiple sclerosis (MS) is located at the human leukocyte antigen (HLA) class II DRB1 and DQB1 loci.

OBJECTIVES

To investigate the possible role of predisposing HLA genotypes in determining brain atrophy.

METHODS

HLA genotypes were categorized as high risk (two predisposing haplotypes) or medium/low risk (one or no predisposing haplotypes). Patients underwent a brain magnetic resonance imaging (MRI) study and volumes of white matter (WM), gray matter (GM), and whole brain (WB) were estimated with SIENAX. Longitudinal atrophy was also assessed with SIENA.

RESULTS

The study included 240 MS patients. In 51/240 (21%) subjects, a high-risk HLA genotype was observed, while medium- and low-risk HLA genotypes were 109/240 (45%) and 80/240 (34%), respectively. Multiple regression analysis found that the high-risk HLA genotype was associated with significant reduction in WB ( p = 0.02) and GM ( p = 0.03) volumes compared with the medium-/low-risk HLA genotypes, independently from MS clinical features. The longitudinal study included 60 patients and showed a brain volume loss of -0.79% in high-risk HLA genotype group versus -0.56% in low-risk HLA genotype.

CONCLUSION

Our results suggest an influence of HLA genotype on WB and GM atrophy. Further investigations are necessary to confirm these findings.

Primary Progressive Multiple Sclerosis: Putting Together the Puzzle

The focus of multiple sclerosis research has recently turned to the relatively rare and clearly more challenging condition of primary progressive multiple sclerosis (PPMS). Many risk factors such as genetic susceptibility, age, and Epstein–Barr virus (EBV) infection may interdepend on various levels, causing a complex pathophysiological cascade. Variable pathological mechanisms drive disease progression, including inflammation-associated axonal loss, continuous activation of central nervous system resident cells, such as astrocytes and microglia as well as mitochondrial dysfunction and iron accumulation. Histological studies revealed diffuse infiltration of the gray and white matter as well as of the meninges with inflammatory cells such as B-, T-, natural killer, and plasma cells. While numerous anti-inflammatory agents effective in relapsing remitting multiple sclerosis basically failed in treatment of PPMS, the B-cell-depleting monoclonal antibody ocrelizumab recently broke the dogma that PPMS cannot be treated by an anti-inflammatory approach by demonstrating efficacy in a phase 3 PPMS trial. Other treatments aiming at enhancing remyelination (MD1003) as well as EBV-directed treatment strategies may be promising agents on the horizon. In this article, we aim to summarize new advances in the understanding of risk factors, pathophysiology, and treatment of PPMS. Moreover, we introduce a novel concept to understand the nature of the disease and possible treatment strategies in the near future.

Association of HLA Genetic Risk Burden With Disease Phenotypes in Multiple Sclerosis

IMPORTANCE

Although multiple HLA alleles associated with multiple sclerosis (MS) risk have been identified, genotype-phenotype studies in the HLA region remain scarce and inconclusive.

OBJECTIVES

To investigate whether MS risk-associated HLA alleles also affect disease phenotypes.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional, case-control study comprising 652 patients with MS who had comprehensive phenotypic information and 455 individuals of European origin serving as controls was conducted at a single academic research site. Patients evaluated at the Multiple Sclerosis Center at University of California, San Francisco between July 2004 and September 2005 were invited to participate. Spinal cord imaging in the data set was acquired between July 2013 and March 2014; analysis was performed between December 2014 and December 2015.

MAIN OUTCOMES AND MEASURES

Cumulative HLA genetic burden (HLAGB) calculated using the most updated MS-associated HLA alleles vs clinical and magnetic resonance imaging outcomes, including age at onset, disease severity, conversion time from clinically isolated syndrome to clinically definite MS, fractions of cortical and subcortical gray matter and cerebral white matter, brain lesion volume, spinal cord gray and white matter areas, upper cervical cord area, and the ratio of gray matter to the upper cervical cord area. Multivariate modeling was applied separately for each sex data set.

RESULTS

Of the 652 patients with MS, 586 had no missing genetic data and were included in the HLAGB analysis. In these 586 patients (404 women [68.9%]; mean [SD] age at disease onset, 33.6 [9.4] years), HLAGB was higher than in controls (median [IQR], 0.7 [0-1.4] and 0 [-0.3 to 0.5], respectively; P = 1.8 × 10-27). A total of 619 (95.8%) had relapsing-onset MS and 27 (4.2%) had progressive-onset MS. No significant difference was observed between relapsing-onset MS and primary progressive MS. A higher HLAGB was associated with younger age at onset and the atrophy of subcortical gray matter fraction in women with relapsing-onset MS (standard β = -1.20 × 10-1; P = 1.7 × 10-2 and standard β = -1.67 × 10-1; P = 2.3 × 10-4, respectively), which were driven mainly by the HLA-DRB1*15:01 haplotype. In addition, we observed the distinct role of the HLA-A*24:02-B*07:02-DRB1*15:01 haplotype among the other common DRB1*15:01 haplotypes and a nominally protective effect of HLA-B*44:02 to the subcortical gray atrophy (standard β = -1.28 × 10-1; P = 5.1 × 10-3 and standard β = 9.52 × 10-2; P = 3.6 × 10-2, respectively).

CONCLUSIONS AND RELEVANCE

We confirm and extend previous observations linking HLA MS susceptibility alleles with disease progression and specific clinical and magnetic resonance imaging phenotypic traits.

HLA-DRB1*04:05 allele is associated with intracortical lesions on three-dimensional double inversion recovery images in Japanese patients with multiple sclerosis

BACKGROUND

Cortical lesions (CLs) frequently observed in Caucasian patients with multiple sclerosis (MS) contribute to disability. However, it remains unclear whether CLs are associated with clinical features and genetic risk factors, such as HLA-DRB1*15:01 and -DRB1*04:05 in Asian MS patients.

OBJECTIVE

To elucidate the frequency of CLs and their association with HLA-DRB1 and DPB1 alleles in Japanese MS patients.

METHODS

Three-dimensional double inversion recovery imaging and clinical information were retrospectively obtained from 92 Japanese MS patients.

RESULTS

CLs of any type, intracortical lesions (ICLs), and leukocortical lesions (LCLs) were detected in 39.1%, 26.1%, and 28.3% of patients, respectively. MS patients with ICLs had a significantly higher frequency of secondary progression and greater Expanded Disability Status Scale (EDSS) scores than those without ICLs. Similar trends were observed with CLs and LCLs. The number of all three lesion types positively correlated with EDSS scores. The frequency and number of ICLs were significantly higher in HLA-DRB1*15:01 carriers than in HLA-DRB1*15:01 non-carriers, but significantly lower in HLA-DRB1*04:05 carriers than in HLA-DRB1*04:05 non-carriers. Multivariate logistic regression analysis revealed a negative association of HLA-DRB1*04:05 with ICLs.

CONCLUSION

ICLs are associated with greater disease severity in Japanese MS patients and are partly suppressed by the HLA-DRB1*04:05 allele.

HLA genotype as a marker of multiple sclerosis prognosis: A pilot study

OBJECTIVE

The identification of a biomarker with prognostic value is an unmet need in multiple sclerosis (MS). The objective of this study was to investigate a possible association of HLA genotype with disease status and progression in MS, based on comprehensive and sensitive clinical and magnetic resonance imaging (MRI) parameters to measure disease effects.

METHOD

A total of 118 MS patients (79 females, 39 males) underwent HLA typing. Patient MS status was assessed at two time points in a 2-year interval, based on clinical scores (including EDSS, MSSS, T25FW, 9-HPT, SDMT, BVMT, CVLT-II) and MRI evaluations. Quantitative brain MRI values were obtained for whole brain atrophy, FLAIR lesion volume change and number of new lesions using MSmetrix. Predefined HLA patient groups were compared as of disease status and progression. Global assessment was achieved by an overall t-statistic and assessment per measurement by a Welch test and/or Mann Whitney U test. The effects of multiple covariates, including age, gender and disease duration as well as scan parameters, were also evaluated using a regression analysis.

RESULTS

The HLA-A*02 allele was associated with better outcomes in terms of MSSS, EDSS and new lesion count (Welch test p-value<0.05). The HLA-B*07 and HLA-B*44 alleles showed a global negative effect on disease status, although none of the measurements reached significance (p-value<0.05). Results for the HLA-DRB1*15, HLA-DQB1*06 and HLA-B*08 alleles were inconclusive. The influence of the confounding variables on the statistical analysis was limited.

Role of Oligodendrocyte Dysfunction in Demyelination, Remyelination and Neurodegeneration in Multiple Sclerosis

Oligodendrocytes (OLs) are the myelinating cells of the central nervous system (CNS) during development and throughout adulthood. They result from a complex and well controlled process of activation, proliferation, migration and differentiation of oligodendrocyte progenitor cells (OPCs) from the germinative niches of the CNS. In multiple sclerosis (MS), the complex pathological process produces dysfunction and apoptosis of OLs leading to demyelination and neurodegeneration. This review attempts to describe the patterns of demyelination in MS, the steps involved in oligodendrogenesis and myelination in healthy CNS, the different pathways leading to OLs and myelin loss in MS, as well as principles involved in restoration of myelin sheaths. Environmental factors and their impact on OLs and pathological mechanisms of MS are also discussed. Finally, we will present evidence about the potential therapeutic targets in re-myelination processes that can be accessed in order to develop regenerative therapies for MS.

A genetic basis for multiple sclerosis severity: Red herring or real?

Multiple Sclerosis (MS) is an autoimmune degenerative disease of the central nervous system, characterized by multifocal demyelination and neurodegeneration. The genetic architecture of MS is complex, where genetic risk has been attributed to over 100 polymorphic loci each with small odds ratios. MS is a highly heterogeneous disease with numerous clinical and paraclinical endophenotypes. To-date, no genetic variant has been associated with clinical outcome, however, evidence exists that MS outcomes, like risk, are to an extent also controlled by genetic variation. Here we summarise the current evidence for genetic determination of disease outcomes and make recommendations for future research directions.

Multiple sclerosis risk loci and disease severity in 7,125 individuals from 10 studies

OBJECTIVE

We investigated the association between 52 risk variants identified through genome-wide association studies and disease severity in multiple sclerosis (MS).

METHODS

Ten unique MS case data sets were analyzed. The Multiple Sclerosis Severity Score (MSSS) was calculated using the Expanded Disability Status Scale at study entry and disease duration. MSSS was considered as a continuous variable and as 2 dichotomous variables (median and extreme ends; MSSS of ≤5 vs >5 and MSSS of <2.5 vs ≥7.5, respectively). Single nucleotide polymorphisms (SNPs) were examined individually and as both combined weighted genetic risk score (wGRS) and unweighted genetic risk score (GRS) for association with disease severity. Random-effects meta-analyses were conducted and adjusted for cohort, sex, age at onset, and HLA-DRB1*15:01.

RESULTS

A total of 7,125 MS cases were analyzed. The wGRS and GRS were not strongly associated with disease severity after accounting for cohort, sex, age at onset, and HLA-DRB1*15:01. After restricting analyses to cases with disease duration ≥10 years, associations were null (p value ≥0.05). No SNP was associated with disease severity after adjusting for multiple testing.

CONCLUSIONS

The largest meta-analysis of established MS genetic risk variants and disease severity, to date, was performed. Results suggest that the investigated MS genetic risk variants are not associated with MSSS, even after controlling for potential confounders. Further research in large cohorts is needed to identify genetic determinants of disease severity using sensitive clinical and MRI measures, which are critical to understanding disease mechanisms and guiding development of effective treatments.

Clinical relevance of brain atrophy assessment in multiple sclerosis. Implications for its use in a clinical routine

INTRODUCTION

Brain atrophy measurement in multiple sclerosis (MS) has become an important outcome for determining patients at risk for developing physical and cognitive disability.

AREAS COVERED

In this article, we discuss the methodological issues related to using this MRI metric routinely, in a clinical setting. Understanding trajectories of annualized whole brain, gray and white matter, thalamic volume loss, and enlargement of ventricular space in specific MS phenotypes is becoming increasingly important. Evidence is mounting that disease-modifying treatments exert a positive effect on slowing brain atrophy progression in MS. Expert Commentary: While there is a need to translate measurement of brain atrophy to clinical routine at the individual patient level, there are still a number of challenges to be met before this can actually happen, including how to account for biological confounding factors and pseudoatrophy, standardize acquisition and analyses parameters, which can influence the accuracy of the assessments.