Humoral immune response to EBV in multiple sclerosis is associated with disease activity on MRI

Altered EBV specific immune control in multiple sclerosis

Since the 1980s it is known that immune responses to the Epstein-Barr virus (EBV) are elevated in multiple sclerosis (MS) patients. Recent seroepidemiologial data have shown that this alteration after primary EBV infection identifies individuals with a more than 30-fold increased risk to develop MS. The mechanisms by which EBV infection might erode tolerance for the central nervous system (CNS) in these individuals, years prior to clinical MS onset, remain unclear. In this review I will discuss altered frequencies of EBV life cycle stages and their tissue distribution, EBV with CNS autoantigen cross-reactive immune responses and loss of immune control for autoreactive B and T cells as possible mechanisms. This discussion is intended to stimulate future studies into these mechanisms with the aim to identify candidates for interventions that might correct EBV specific immune control and/or resulting cross-reactivities with CNS autoantigens in MS patients and thereby ameliorate disease activity.

Evaluating the Clinical Utility of Epstein-Barr Virus Antibodies as Biomarkers in Multiple Sclerosis: A Systematic Review

BACKGROUND

EBV is a necessary but not sufficient factor in the pathophysiology of multiple sclerosis (MS). EBV antibodies to the nuclear antigen (EBNA1) and viral capsid antigen (VCA) rise rapidly prior to MS disease manifestations, and their absence has clinical utility with a high negative predictive value. It remains unclear whether EBV levels act as prognostic, monitoring, or pharmacodynamic/response biomarkers. Substantial literature on this topic exists but has not been systematically reviewed. We hypothesized that EBV levels against EBNA1 and VCA are potential prognostic and monitoring biomarkers in MS, and that patient population, MS clinical phenotype, and EBV assay method may play important roles in explaining variation among study outcomes.

METHODS

We systematically searched PubMed and EMBASE from inception to April 1, 2022. After removal of duplicates, records were screened by abstract. Remaining full-text articles were reviewed. Clinical and MRI data were extracted from full-text articles for comparison and synthesis.

RESULTS

Searches yielded 696 unique results; 285 were reviewed in full, and 36 met criteria for data extraction. Heterogeneity in sample population, clinical outcome measures, assay methods and statistical analyses precluded a meta-analysis. EBV levels were not consistently associated with clinical disease markers including conversion from CIS to RRMS, neurological disability, or disease phenotype. Studies using repeated-measures design suggest that EBNA1 levels may temporarily reflect inflammatory disease activity as assessed by gadolinium-enhancing Magnetic Resonance Imaging (MRI) lesions. Limited data also suggest a decrease in EBV levels following initiation of certain disease-modifying therapies.

CONCLUSION

Heterogeneous methodology limited generalization and meta-analysis. EBV antibody levels are unlikely to represent prognostic biomarkers in MS. The areas of highest ongoing promise relate to diagnostic exclusion and pharmacodynamic/disease response. Use of EBV antibodies as biomarkers in clinical practice remains additionally limited by lack of methodological precision, reliability, and validation.

How to and should we target EBV in MS?

INTRODUCTION

The etiology of multiple sclerosis (MS) remains unknown. Pathogenesis likely relies on a complex interaction between multiple environmental, genetic, and behavioral risk factors. However, a growing body of literature supports the role of a preceding Epstein Barr Virus (EBV) infection in the majority of cases.

AREAS COVERED

In this narrative review, we summarize the latest findings regarding the potential role of EBV as a predisposing event inducing new onset of MS. EBV interactions with the genetic background and other infectious agents such as human endogenous retrovirus are explored. Additional data regarding the role of EBV regarding the rate of mid- and long-term disease progression is also discussed. Lastly, the effect of currently approved disease modifying therapies (DMT) for MS treatment on the EBV-based molecular mechanisms and the development of new EBV-specific therapies are further reviewed.

EXPERT OPINION

Recent strong epidemiological findings support that EBV may be the primary inducing event in certain individuals that shortly thereafter develop MS. More studies are needed in order to better understand the significant variability in susceptibility based on environmental factors such as EBV exposure. Future investigations should focus on determining the specific EBV-related risk antigen(s) and phenotyping people with likely EBV-induced MS. Targeting EBV via several different avenues, including development of an EBV vaccine may become the mainstay of MS treatment in the future.

Expanded T lymphocytes in the cerebrospinal fluid of multiple sclerosis patients are specific for Epstein-Barr-virus-infected B cells

Epstein-Barr virus (EBV) infection has long been associated with multiple sclerosis (MS), but the role of EBV in the pathogenesis of MS is not clear. Our hypothesis is that a major fraction of the expanded clones of T lymphocytes in the cerebrospinal fluid (CSF) are specific for autologous EBV-infected B cells. We obtained blood and CSF samples from eight relapsing-remitting patients in the process of diagnosis. We stimulated cells from the blood with autologous EBV-infected lymphoblastoid cell lines (LCL), EBV, varicella zoster virus, influenza, and candida and sorted the responding cells with flow cytometry after 6 d. We sequenced the RNA for T cell receptors (TCR) from CSF, unselected blood cells, and the antigen-specific cells. We used the TCR Vβ CDR3 sequences from the antigen-specific cells to assign antigen specificity to the sequences from the CSF and blood. LCL-specific cells comprised 13.0 ± 4.3% (mean ± SD) of the total reads present in CSF and 13.3 ± 7.5% of the reads present in blood. The next most abundant antigen specificity was flu, which was 4.7 ± 1.7% of the reads in the CSF and 9.3 ± 6.6% in the blood. The prominence of LCL-specific reads was even more marked in the top 1% most abundant CSF clones with statistically significant 47% mean overlap with LCL. We conclude that LCL-specific sequences form a major portion of the TCR repertoire in both CSF and blood and that expanded clones specific for LCL are present in MS CSF. This has important implications for the pathogenesis of MS.

A phase 2a open-label clinical trial to determine the effect of famciclovir on EBV activity as measured by EBV shedding in the saliva of patients with multiple sclerosis

BACKGROUND

Despite increasing evidence that Epstein-Barr virus (EBV) plays a causal role in MS, no treatments have been shown to reduce EBV turnover. We studied the effect of famciclovir on salivary EBV shedding in people with MS (NCT05283551) in a pilot, proof-of-concept study.

METHODS

People with MS receiving natalizumab provided weekly saliva samples for 12 weeks before starting famciclovir 500 mg twice daily for 12 weeks. Twelve saliva samples were provided on treatment and 12 following treatment. A real-time qPCR Taqman assay was used to detect EBV DNA in saliva. The proportion of saliva samples containing EBV DNA was compared using the Friedman test.

RESULTS

Of 30 participants (19 F; mean age 41 years; median EDSS 3.5), 29 received famciclovir, and 24 completed the 12-week course. Twenty-one participants provided at least one usable saliva sample in all epochs. Ten of the 21 had shedding in at least one sample pre-drug; 7/21 when taking famciclovir (not significant). No difference in EBV DNA copy number was seen. There were no drug-related serious adverse events.

CONCLUSION

No significant effect of famciclovir on EBV shedding was seen in this small pilot study. Given the low numbers, a small effect of famciclovir cannot be excluded. Salivary EBV shedding in this natalizumab-treated cohort was lower than in previous studies, which requires replication.

Humoral response to Epstein-Barr virus in patients with multiple sclerosis treated with B cell depletion therapy

BACKGROUND

B cell depletion therapy is highly effective in relapsing-remitting multiple sclerosis (RRMS). However, the precise underlying mechanisms of action for its biological effects in MS have still not been clarified. Epstein-Barr virus (EBV) is a known risk factor for MS and seems to be a prerequisite for disease development. EBV resides latently in the memory B cells, and may not only increase the risk of developing MS, but also contribute to disease activity and disability progression. Therefore, the effects of B cell depletion in MS could be associated with the depletion of EBV-infected cells and the altered immune response to the virus. In this study, we investigate the impact of B cell depletion on the humoral immune response specific to EBV in patients with MS.

METHODS

Newly diagnosed, treatment-naïve patients with RRMS were followed up to 18 months after initiation of B-cell depletion therapy in the Overlord-MS study, a phase III trial (NCT04578639). We analyzed serum sampled before treatment and after 3, 6, 12 and 18 months for immunoglobulin γ (IgG) against Epstein-Barr nuclear antigen 1 (EBNA1) and Epstein-Barr viral capsid antigen (VCA). We analyzed antibodies to cytomegalovirus (CMV) and total IgG in serum, as controls for viral and overall humoral immunity. The risk allele, HLA-DRB1*15:01, and the protective allele, HLA-A*02:01, were determined in all participants. In addition, polymerase chain reaction (PCR) for circulating EBV-DNA was performed in the first 156 samples drawn. The associations between time on B cell-depletion therapy and serum anti-EBV antibody levels were estimated using linear mixed-effects models.

RESULTS

A total of 290 serum samples from 99 patients were available for analysis. After 6, 12 and 18 months, the EBNA1 IgG levels decreased by 12.7 % (95 % CI -18.8 to -6.60, p < 0.001), 12.1 % (95 % CI -19.8 to -3.7, p = 0.006) and 14.6 % (95 % CI to -25.3 to -2.4, p = 0.02) respectively, compared to baseline level. Carriers of the HLA-DRB1*15:01 allele had higher EBNA1 IgG levels at baseline (p = 0.02). The VCA IgG levels significantly increased by 13.7 % (95 % CI 9.4 to 18.1, p < 0.001) after 3 months, compared to baseline, and persisted at this level throughout the follow-up. CMV IgG levels decreased, but to a lesser extent than the decrease of EBNA1 IgG, and total IgG levels decreased during therapy. Circulating EBV-DNA was found in only three of 156 samples from 64 patients.

CONCLUSIONS

EBNA1 IgG levels decreased, while VCA IgG levels increased, during B cell depletion therapy. This supports the hypothesis that the mechanism of action for B cell depletion therapy might be mediated by effects on EBV infection, which, in turn, mitigate immune cross-reactivity and disease perpetuation.

Clinical predictors of NEDA-3 one year after diagnosis of pediatric multiple sclerosis: an exploratory single-center study

Introduction

Multiple sclerosis (MS) is an inflammatory and demyelinating disorder of central nervous system that can be diagnosed in pediatric age (<18 years) in 3-5% of the cases. This early onset is associated with higher relapse rates and earlier progression to neurological disability. By using NEDA-3 (No Evidence of Disease Activity-3) criteria, we aimed to identify clinical predictors associated with absence of disease activity and control of disease progression 12 months after the diagnosis, in a cohort of pediatric-onset MS (POMS) patients regularly followed-up in our center.

Methods

We analyzed demographic, clinical, laboratorial and imaging variables of patients with POMS identified in our center, between 2010 and 2021, in two moments: at the diagnosis and 12 months after it. Statistical tests were applied to compare the distribution of those variables between groups defined by NEDA-3 status and by each one of its three variable components.

Results

We included 27 patients in the study (18 female), with a mean age of 14.8 years (± 2.8), being all diagnosed with relapsing-remitting MS and with a median score of 1.5 at the Expanded Disability Status Scale (EDSS). The use of natalizumab (p = 0.017) and the negativity for anti-EBV IgG antibodies (p = 0.018) at diagnosis were associated with a higher achievement of NEDA-3 status 12 months after, in our cohort. Prescribed treatment was also associated with statistically significant differences in the "absence of MRI activity" component of NEDA-3 (p = 0.006): patients under treatment with natalizumab had a higher probability of achieving this status, and the opposite was observed in glatiramer acetate-treated children.

Discussion and conclusion

Our exploratory results underline the pivotal importance that an early and more effective therapeutical approach may have in the control of disease activity, in POMS. Additionally, they also seem to suggest that the presence of anti-EBV antibodies is not innocent, as it can be related to a less favorable evolution of the disease, even at a very early stage. Further studies are needed to confirm the applicability of these variables as prognostic and personalized tools in this clinical setting.

EBNA1 Inhibitors Block Proliferation of Spontaneous Lymphoblastoid Cell Lines From Patients With Multiple Sclerosis and Healthy Controls

BACKGROUND AND OBJECTIVES

Epstein-Barr virus (EBV) is a ubiquitous herpesvirus that establishes lifelong latency in memory B cells and has been identified as a major risk factor of multiple sclerosis (MS). B cell depletion therapies have disease-modifying benefit in MS. However, it is unclear whether this benefit is partly attributable to the elimination of EBV+ B cells. Currently, there are no EBV-specific antiviral therapies available for targeting EBV latent infection in MS and limited experimental models to study EBV in MS.

METHODS

In this study, we describe the establishment of spontaneous lymphoblastoid cell lines (SLCLs) generated ex vivo with the endogenous EBV of patients with MS and controls and treated with either an Epstein-Barr virus nuclear antigen 1 (EBNA1) inhibitor (VK-1727) or cladribine, a nucleoside analog that eliminates B cells.

RESULTS

We showed that a small molecule inhibitor of EBNA1, a critical regulator of the EBV life cycle, blocks the proliferation and metabolic activity of these SLCLs. In contrast to cladribine, a highly cytotoxic B cell depleting therapy currently used in MS, the EBNA1 inhibitor VK-1727 was cytostatic rather than cytotoxic and selective for EBV+ cells, while having no discernible effects on EBV- cells. We validate that VK-1727 reduces EBNA1 DNA binding at known viral and cellular sites by ChIP-qPCR.

DISCUSSION

This study shows that patient-derived SLCLs provide a useful tool for interrogating the role of EBV+ B cells in MS and suggests that a clinical trial testing the effect of EBNA1 inhibitors in MS may be warranted.

Higher frequency of Human herpesvirus-6 (HHV-6) viral DNA simultaneously with low frequency of Epstein-Barr virus (EBV) viral DNA in a cohort of multiple sclerosis patients from Rio de Janeiro, Brazil

Multiple sclerosis (MS) is a chronic neuroinflammatory and neurodegenerative disease of the central nervous system (CNS). The etiology of MS is not well understood, but it's likely one of the genetic and environmental factors. Approximately 85% of patients have relapsing-remitting MS (RRMS), while 10-15% have primary progressive MS (PPMS). Epstein-Barr virus (EBV) and Human herpesvirus 6 (HHV-6), members of the human Herpesviridae family, are strong candidates for representing the macroenvironmental factors associated with MS) pathogenesis. Antigenic mimicry of EBV involving B-cells has been implicate in MS risk factors and concomitance of EBV and HHV-6 latent infection has been associated to inflammatory MS cascade. To verify the possible role of EBV and HHV-6 as triggering or aggravating factors in RRMS and PPMS, we compare their frequency in blood samples collected from 166 MS patients. The presence of herpes DNA was searched by real-time PCR (qPCR). The frequency of EBV and HHV-6 in MS patients were 1.8% (3/166) and 8.9% (14/166), respectively. Among the positive patients, 100% (3/3) EBV and 85.8% (12/14) HHV-6 are RRMS and 14.4% (2/14) HHV-6 are PPMS. Detection of EBV was 1.2% (2/166) and HHV-6 was 0.6% (1/166) in blood donors. About clinical phenotype of these patients, incomplete multifocal myelitis, and optic neuritis were the main CNS manifestations. These are the first data about concomitant infection of these viruses in MS patients from Brazil. Up to date, our findings confirm a higher prevalence in female with MS and a high frequency of EBV and HHV-6 in RRMS patients.

The association of upper respiratory infections with neuro-radiological course and attack rate of multiple sclerosis: Results from a large prospective cohort

Background

Although upper respiratory infections (URIs) are linked to multiple sclerosis (MS) attacks, SARS-COV2 has not been compared to URIs for attack rates.

Objectives

This study aimed to evaluate the attack rate and the results of neuroimaging in MS patients with URIs caused by COVID-19 and non-COVID-19 infections (NC-URI).

Methods

From May 2020 to April 2021, we followed 362 patients with relapsing-remitting MS in a prospective cohort design. Patients were monitored regularly every 12 weeks; an magnetic resonance imaging (MRI) scan was performed at enrollment and every time a relapse occurred. Poisson analysis was used to determine exacerbation rate ratios (RR) and the MRI parameters were tested using chi-square analysis.

Results

347 patients with an average age of 38 and a female ratio of 86% were included. A RR of 2.24 (p < 0.001) was observed for exacerbations during the at-risk period (ARP). Attacks related to COVID-19 (RR = 2.13, p = 0.001) and NC-URIs (RR = 2.39, p < 0.001) were comparable regarding the increased risk of exacerbation (p = 0.62). Exacerbations within or outside the ARP did not significantly alter the number of baseline GAD-enhancing lesions (p > 0.05 for both).

Conclusion

COVID-19 has been shown to increase the risk of MS exacerbations, like other viral URIs.

Cellular and Molecular Evidence of Multiple Sclerosis Diagnosis and Treatment Challenges

Multiple sclerosis (MS) is a chronic autoimmune disease that impacts the central nervous system and can result in disability. Although the prevalence of MS has increased in India, diagnosis and treatment continue to be difficult due to several factors. The present study examines the difficulties in detecting and treating multiple sclerosis in India. A lack of MS knowledge among healthcare professionals and the general public, which delays diagnosis and treatment, is one of the significant issues. Inadequate numbers of neurologists and professionals with knowledge of MS management also exacerbate the situation. In addition, MS medications are expensive and not covered by insurance, making them inaccessible to most patients. Due to the absence of established treatment protocols and standards for MS care, India's treatment techniques vary. In addition, India's population diversity poses unique challenges regarding genetic variations, cellular and molecular abnormalities, and the potential for differing treatment responses. MS is more difficult to accurately diagnose and monitor due to a lack of specialized medical supplies and diagnostic instruments. Improved awareness and education among healthcare professionals and the general public, as well as the development of standardized treatment regimens and increased investment in MS research and infrastructure, are required to address these issues. By addressing these issues, it is anticipated that MS diagnosis and treatment in India will improve, leading to better outcomes for those affected by this chronic condition.

The Role of Microorganisms in the Etiopathogenesis of Demyelinating Diseases

Multiple sclerosis (MS), neuromyelitis optica (NMO) and myelin oligodendrocyte glycoprotein antibody disease (MOGAD) are inflammatory diseases of the central nervous system (CNS) with a multifactorial aetiology. Environmental factors are important for their development and microorganisms could play a determining role. They can directly damage the CNS, but their interaction with the immune system is even more important. The possible mechanisms involved include molecular mimicry, epitope spreading, bystander activation and the dual cell receptor theory. The role of Epstein-Barr virus (EBV) in MS has been definitely established, since being seropositive is a necessary condition for the onset of MS. EBV interacts with genetic and environmental factors, such as low levels of vitamin D and human endogenous retrovirus (HERV), another microorganism implicated in the disease. Many cases of onset or exacerbation of neuromyelitis optica spectrum disorder (NMOSD) have been described after infection with Mycobacterium tuberculosis, EBV and human immunodeficiency virus; however, no definite association with a virus has been found. A possible role has been suggested for Helicobacter pylori, in particular in individuals with aquaporin 4 antibodies. The onset of MOGAD could occur after an infection, mainly in the monophasic course of the disease. A role for the HERV in MOGAD has been hypothesized. In this review, we examined the current understanding of the involvement of infectious factors in MS, NMO and MOGAD. Our objective was to elucidate the roles of each microorganism in initiating the diseases and influencing their clinical progression. We aimed to discuss both the infectious factors that have a well-established role and those that have yielded conflicting results across various studies.

Epstein-Barr Virus and Multiple Sclerosis: A Convoluted Interaction and the Opportunity to Unravel Predictive Biomarkers

Since the early 1980s, Epstein-Barr virus (EBV) infection has been described as one of the main risk factors for developing multiple sclerosis (MS), and recently, new epidemiological evidence has reinforced this premise. EBV seroconversion precedes almost 99% of the new cases of MS and likely predates the first clinical symptoms. The molecular mechanisms of this association are complex and may involve different immunological routes, perhaps all running in parallel (i.e., molecular mimicry, the bystander damage theory, abnormal cytokine networks, and coinfection of EBV with retroviruses, among others). However, despite the large amount of evidence available on these topics, the ultimate role of EBV in the pathogenesis of MS is not fully understood. For instance, it is unclear why after EBV infection some individuals develop MS while others evolve to lymphoproliferative disorders or systemic autoimmune diseases. In this regard, recent studies suggest that the virus may exert epigenetic control over MS susceptibility genes by means of specific virulence factors. Such genetic manipulation has been described in virally-infected memory B cells from patients with MS and are thought to be the main source of autoreactive immune responses. Yet, the role of EBV infection in the natural history of MS and in the initiation of neurodegeneration is even less clear. In this narrative review, we will discuss the available evidence on these topics and the possibility of harnessing such immunological alterations to uncover predictive biomarkers for the onset of MS and perhaps facilitate prognostication of the clinical course.

COVID-19 and its implications on the clinico-radiological course of multiple sclerosis: A case-control study

BACKGROUND

Multiple sclerosis (MS) is an immune-mediated disease that has been related to several risk factors such as various viral infections. We carried out this study in order to establish a relationship between COVID-19 infection and MS severity.

METHODS

In a case-control study, we recruited patients with relapsing-remitting multiple sclerosis (RRMS). Patients were divided into two groups based on positive COVID-19 PCR at the end of the enrollment phase. Each patient was prospectively followed for 12 months. Demographical, clinical, and past medical history were collected during routine clinical practice. Assessments were performed every six months; MRI was performed at enrollment and 12 months later.

RESULTS

Three hundred and sixty-two patients participated in this study. MS patients with COVID-19 infection had significantly higher increases in the number of MRI lesions (p: 0.019, OR(CI): 6.37(1.54-26.34)) and EDSS scores (p: 0.017), but no difference was found in total annual relapses or relapse rates. COVID-19 infections were positively correlated with EDSS progression (p: 0.02) and the number of new MRI lesions (p: 0.004) and predicted the likelihood of the number of new MRI lesions by an odds of 5.92 (p: 0.018).

CONCLUSION

COVID-19 may lead to higher disability scores in the RRMS population and is associated with developing new Gd-enhancing lesions in MRI imaging. However, no difference was observed between the groups regarding the number of relapses during follow-up.

COVID-19 and its implications on the clinico-radiological course of multiple sclerosis: A case-control study

Background

Multiple sclerosis (MS) is an immune-mediated disease that has been related to several risk factors such as various viral infections. We carried out this study in order to establish a relationship between COVID-19 infection and MS severity.

Methods

In a case-control study, we recruited patients with relapsing-remitting multiple sclerosis (RRMS). Patients were divided into two groups based on positive COVID-19 PCR at the end of the enrollment phase. Each patient was prospectively followed for 12 months. Demographical, clinical, and past medical history were collected during routine clinical practice. Assessments were performed every six months; MRI was performed at enrollment and 12 months later.

Results

Three hundred and sixty-two patients participated in this study. MS patients with COVID-19 infection had significantly higher increases in the number of MRI lesions (p: 0.019, OR(CI): 6.37(1.54-26.34)) and EDSS scores (p: 0.017), but no difference was found in total annual relapses or relapse rates. COVID-19 infections were positively correlated with EDSS progression (p: 0.02) and the number of new MRI lesions (p: 0.004) and predicted the likelihood of the number of new MRI lesions by an odds of 5.92 (p: 0.018).

Conclusion

COVID-19 may lead to higher disability scores in the RRMS population and is associated with developing new Gd-enhancing lesions in MRI imaging. However, no difference was observed between the groups regarding the number of relapses during follow-up.

Epstein-Barr virus as a leading cause of multiple sclerosis: mechanisms and implications

Epidemiological studies have provided compelling evidence that multiple sclerosis (MS) is a rare complication of infection with the Epstein-Barr virus (EBV), a herpesvirus that infects more than 90% of the global population. This link was long suspected because the risk of MS increases markedly after infectious mononucleosis (symptomatic primary EBV infection) and with high titres of antibodies to specific EBV antigens. However, it was not until 2022 that a longitudinal study demonstrated that MS risk is minimal in individuals who are not infected with EBV and that it increases over 30-fold following EBV infection. Over the past few years, a number of studies have provided clues on the underlying mechanisms, which might help us to develop more targeted treatments for MS. In this Review, we discuss the evidence linking EBV to the development of MS and the mechanisms by which the virus is thought to cause the disease. Furthermore, we discuss implications for the treatment and prevention of MS, including the use of antivirals and vaccines.

Increased cytomegalovirus immune responses at disease onset are protective in the long-term prognosis of patients with multiple sclerosis

OBJECTIVE

It remains unclear whether viral infections interfere with multiple sclerosis (MS) disease progression. We evaluated the prognostic role of antibody responses toward viruses determined at disease onset on long-term disease outcomes.

METHODS

Humoral immune responses against Epstein-Barr virus (EBV)-encoded nuclear antigen EBNA1, viral capsid antigen (VCA) and early antigen, and toward cytomegalovirus (HCMV), human herpesvirus 6 and measles were investigated in a cohort of 143 patients with MS for their association with long-term disability and inflammation disease outcomes.

RESULTS

Median (IQR) follow-up was 20 (17.2-22.8) years. In univariable analysis, increased HCMV levels were associated with a lower risk to Expanded Disability Status Scale 4.0 (HR 0.95; 95% CI 0.91 to 0.99; p=0.03), to develop a secondary progressive MS (HR 0.94; 95% CI 0.90 to 0.99; p=0.02) and to first-line treatment (HR 0.98; 95% CI 0.96 to 0.99; p=0.04). High HCMV IgG levels were associated with a longer time to first-line treatment (p=0.01). Increased immune responses against EBV-VCA were associated with higher risk for first-line (HR 1.45; 95% CI 1.12 to 1.88; p=0.005) and second-line treatments (HR 2.03; 95% CI 1.18 to 3.49; p=0.01), and high VCA IgG levels were associated with shorter time to first-line (p=0.004) and second-line (p=0.02) therapies. EBNA1-specific IgG levels correlated with disease severity (0.17; p=0.04) and with an increased relapse rate during follow-up (relapse rate 1.26; 95% CI 1.03 to 1.56; p=0.02) that remained stable in multivariable analysis.

CONCLUSIONS

These results indicate that elevated immune responses against HCMV at disease onset have protective effects on long-term disability and inflammation disease outcomes. Our data also indicate that increased immune responses against EBV in early phases may influence long-term disease prognosis.

Interferon β1a treatment does not influence serum Epstein-Barr virus antibodies in patients with multiple sclerosis

There is increasing evidence of Epstein-Barr virus (EBV) being conditional in multiple sclerosis (MS) pathogenesis and influential for disease activity. Interferon-beta (IFNβ) is a cytokine with antiviral effects used to treat MS, in which a possible antiviral effect against EBV has been questioned. In this study, we investigated the effect of IFNβ-1a treatment on serum EBV antibody levels in 84 patients with relapsing-remitting MS. In the 18 months following IFNβ-1a treatment initiation, there were no significant associations between treatment and serum levels of Epstein-Barr nuclear antigen 1 (EBNA-1) immunoglobulin (Ig) G, early antigen (EA) IgG, viral capsid antigen (VCA) IgG or VCA IgM. The findings suggest that IFNβ-1a treatment does not influence the humoral response to EBV in patients with MS.

Dimethyl Fumarate Treatment Reduces the Amount but Not the Avidity of the Epstein-Barr Virus Capsid-Antigen-Specific Antibody Response in Multiple Sclerosis: A Pilot Study

(1) Multiple sclerosis (MS) is a chronic inflammatory disease of autoimmune origin. The Epstein−Barr virus (EBV) is associated with the onset of MS, as almost all patients have high levels of EBV-specific antibodies as a result of a previous infection. We evaluated longitudinally the effects of dimethyl fumarate (DMF), a first-line treatment of MS, on the quantity and quality of EBV-specific IgG in MS patients. (2) Serum samples from 17 MS patients receiving DMF were taken before therapy (T0) and after 1 week (T1) and 1 (T2), 3 (T3) and 6 (T4) months of treatment. Anti-EBV nuclear antigen (EBNA)-1 and capsid antigen (CA) IgG levels and anti-CA IgG avidity were measured in all samples. (3) Serum levels of anti-CA IgG were lower at T1 (p = 0.0341), T2 (p = 0.0034), T3 (p < 0.0001) and T4 (p = 0.0023) than T0. These differences were partially confirmed also in anti-EBNA-1 IgG levels (T3 vs. T0, p = 0.0034). All patients had high-avidity anti-CA IgG at T0, and no changes were observed during therapy. (4): DMF can reduce the amount but not the avidity of the anti-EBV humoral immune response in MS patients from the very early stages of treatment.

Potential biological contributers to the sex difference in multiple sclerosis progression

Multiple sclerosis (MS) is an immune-mediated disease that targets the myelin sheath of central nervous system (CNS) neurons leading to axon injury, neuronal death, and neurological progression. Though women are more highly susceptible to developing MS, men that develop this disease exhibit greater cognitive impairment and accumulate disability more rapidly than women. Magnetic resonance imaging and pathology studies have revealed that the greater neurological progression seen in males correlates with chronic immune activation and increased iron accumulation at the rims of chronic white matter lesions as well as more intensive whole brain and grey matter atrophy and axon loss. Studies in humans and in animal models of MS suggest that male aged microglia do not have a higher propensity for inflammation, but may become more re-active at the rim of white matter lesions as a result of the presence of pro-inflammatory T cells, greater astrocyte activation or iron release from oligodendrocytes in the males. There is also evidence that remyelination is more efficient in aged female than aged male rodents and that male neurons are more susceptible to oxidative and nitrosative stress. Both sex chromosome complement and sex hormones contribute to these sex differences in biology.

Epstein-Barr virus antibody in newly diagnosed multiple sclerosis patients and its association with relapse severity and lesion location

BACKGROUND

Epstein-Barr virus is considered a risk factor for the development of multiple sclerosis, and recent findings reveal infected plasma -cells in meningeal ectopic lymphoid deposits. Activation of the dormant virus could be responsible for the multiple sclerosis exacerbation AIMS: To compare Epstein-Barr nuclear IgG (EBNA IgG) titer in newly diagnosed treatment-naive multiple sclerosis patients regarding the diagnoses date, clinical and radiological activity.

METHODS

Treatment-naive multiple sclerosis patients were divided into two groups according to Poser (late group) and McDonald2017(early group) diagnostic criteria. EBNA IgG, EDSS, physical (Timed 25 Foot Walk test, Nine-hole Peg test), and cognitive tests (Brief International Cognitive Assessment for Multiple Sclerosis) were done before the methylprednisolone infusion. The lesion location was evaluated by an MRI. Myelitis was considered a severe attack, and optic neuritis a mild relapse.

RESULTS

In total, 69 patients were enrolled. 44 (63.8%) of them were diagnosed by McDonald2017, and 25 (36.2%) were diagnosed with Poser criteria. There was a significant difference (p = 0.049) between the EBNA IgG titer of the late (median:238 U/ml, IQR: 154-362) and early (median: 154 U/ml, IQR:100.25-293.25). Severe relapse, having a spinal cord lesion, and not being treated with methylprednisolone was associated with higher EBNA IgG titer.

CONCLUSION

Study results show that EBNA IgG was significantly associated with disease activity regarding relapse severity and lesion location and could be a potential biomarker for predicting disease exacerbation.

Gammaherpesvirus infection drives age-associated B cells toward pathogenicity in EAE and MS

While age-associated B cells (ABCs) are known to expand and persist following viral infection and during autoimmunity, their interactions are yet to be studied together in these contexts. Here, we directly compared CD11c⁺T-bet⁺ ABCs using models of Epstein-Barr virus (EBV), gammaherpesvirus 68 (γHV68), multiple sclerosis (MS), and experimental autoimmune encephalomyelitis (EAE), and found that each drives the ABC population to opposing phenotypes. EBV infection has long been implicated in MS, and we have previously shown that latent γHV68 infection exacerbates EAE. Here, we demonstrate that ABCs are required for γHV68-enhanced disease. We then show that the circulating ABC population is expanded and phenotypically altered in people with relapsing MS. In this study, we show that viral infection and autoimmunity differentially affect the phenotype of ABCs in humans and mice, and we identify ABCs as functional mediators of viral-enhanced autoimmunity.

Impact of histone modifier-induced protection against autoimmune encephalomyelitis on multiple sclerosis treatment

Multiple sclerosis is a progressive demyelinating central nervous system disorder with unknown etiology. The condition has heterogeneous presentations, including relapsing-remitting multiple sclerosis and secondary and primary progressive multiple sclerosis. The genetic and epigenetic mechanisms underlying these various forms of multiple sclerosis remain elusive. Many disease-modifying therapies approved for multiple sclerosis are broad-spectrum immunomodulatory drugs that reduce relapses but do not halt the disease progression or neuroaxonal damage. Some are also associated with many severe side effects, including fatalities. Improvements in disease-modifying treatments especially for primary progressive multiple sclerosis remain an unmet need. Several experimental animal models are available to decipher the mechanisms involved in multiple sclerosis. These models help us decipher the advantages and limitations of novel disease-modifying therapies for multiple sclerosis.

Altered Immune Response to the Epstein-Barr Virus as a Prerequisite for Multiple Sclerosis

Strong epidemiologic evidence links Epstein–Barr virus (EBV) infection and its altered immune control to multiple sclerosis (MS) development. Clinical MS onset occurs years after primary EBV infection and the mechanisms linking them remain largely unclear. This review summarizes the epidemiological evidence for this association and how the EBV specific immune control is altered in MS patients. The two main possibilities of mechanisms for this association are further discussed. Firstly, immune responses that are induced during a symptomatic primary EBV infection, namely infectious mononucleosis, might be amplified during the following years to finally cause central nervous system (CNS) inflammation and demyelination. Secondly, genetic predisposition and environmental factors might not allow for an efficient immune control of the EBV-infected B cells that might drive autoimmune T cell stimulation or CNS inflammation. These two main hypotheses for explaining the association of the EBV with MS would implicate opposite therapeutic interventions, namely either dampening CNS inflammatory EBV-reactive immune responses or strengthening them to eliminate the autoimmunity stimulating EBV-infected B cell compartment. Nevertheless, recent findings suggest that EBV is an important puzzle piece in the pathogenesis of MS, and understanding its contribution could open new treatment possibilities for this autoimmune disease.

Serum IgG levels to Epstein-Barr and measles viruses in patients with multiple sclerosis during natalizumab and interferon beta treatment

Background

Patients with multiple sclerosis (MS) demonstrate higher seroprevalence of Epstein-Barr virus (EBV) and increased anti-EBV IgG levels in serum compared with healthy controls. Intrathecal antibody production to measles virus (MeV) is a common finding in patients with MS.

Objective

To measure serum IgG reactivity to EBV glycoprotein 350 (gp350) and MeV nucleocapsid protein (N_CORE) in patients with MS and healthy controls and to determine if reactivity changed in patients during interferon beta (IFNβ) and/or natalizumab (NAT) treatment. A secondary aim was to determine the seroprevalence of EBV in patients and controls.

Methods

Patients with MS (n=728) were included from the Swedish pharmacovigilance study for NAT. Paired serum samples from 714 patients drawn before and during NAT treatment and paired samples from 170 patients during prior IFNβ treatment were analysed. In total, 156 patients were included in both groups. Samples from 144 matched blood donors served as controls. Indirect ELISA was applied using recombinant EBVgp350 and MeV N_CORE as antigens. EBVgp350 IgG seronegative samples were also analysed using EBV nuclear antigen 1 and viral capsid antigen (VCA).

Results

Patients with MS showed higher serum levels of anti-EBVgp350 and anti-MeV N_CORE IgG compared with controls. During NAT treatment, the levels of anti-EBVgp350 and anti-MeV N_CORE IgG declined, compared with the relatively stable levels noted during prior IFNβ treatment. Ten patients failed to demonstrate anti-EBVgp350 IgG but did show detectable anti-VCA IgG, indicating EBV seropositivity. In contrast, 10/144 controls were EBV seronegative.

Conclusions

Treatment with NAT, which is considered a selective immunosuppressive agent with a compartmentalised effect on the central nervous system, appeared to be associated with a moderate decrease in circulating IgG levels to EBVgp350 and MeV N_CORE. All patients with MS were EBV IgG seropositive, supporting the potential role of EBV in the pathogenesis of MS.

Fatty acids role in multiple sclerosis as "metabokines"

Multiple sclerosis (MS), as an autoimmune neurological disease with both genetic and environmental contribution, still lacks effective treatment options among progressive patients, highlighting the need to re-evaluate disease innate properties in search for novel therapeutic targets. Fatty acids (FA) and MS bear an interesting intimate connection. FA and FA metabolism are highly associated with autoimmunity, as the diet-derived circulatory and tissue-resident FAs level and composition can modulate immune cells polarization, differentiation and function, suggesting their broad regulatory role as “metabokines”. In addition, FAs are indeed protective factors for blood–brain barrier integrity, crucial contributors of central nervous system (CNS) chronic inflammation and progressive degeneration, as well as important materials for remyelination. The remaining area of ambiguity requires further exploration into this arena to validate the existed phenomenon, develop novel therapies, and confirm the safety and efficacy of therapeutic intervention targeting FA metabolism.

Association of Latitude and Exposure to Ultraviolet B Radiation With Severity of Multiple Sclerosis: An International Registry Study

BACKGROUND AND OBJECTIVES

The severity of multiple sclerosis (MS) varies widely among individuals. Understanding the determinants of this heterogeneity will help clinicians optimize the management of MS. The aim of this study was to investigate the association between latitude of residence, ultraviolet B radiation exposure (UVB) and the severity of MS.

METHODS

This observational study used the MSBase registry data. The included patients met the 2005 or 2010 McDonald diagnostic criteria for MS and had a minimum dataset recorded in the registry (date of birth, sex, clinic location, date of MS symptom onset, disease phenotype at baseline and censoring, and ≥1 EDSS [Expanded Disability Status Scale] score recorded). The latitude of each study center and cumulative annualized UVB dose at study center (calculated from NASA's Total Ozone Mapping Spectrometer) at ages 6 and 18 and the year of disability assessment were calculated. Disease severity was quantified with MS Severity Score (MSSS). Quadratic regression was used to model the associations between latitude, UVB and MSSS.

RESULTS

46,128 patients contributing 453,208 visits and a cumulative follow-up of 351,196 patient-years (70% women, mean age 39.2±12, resident between latitudes 19°35´ and 56°16´) were included in this study. Latitude showed a non-linear association with MS severity. In latitudes greater than 40°, more severe disease was associated with higher latitudes (β=0.08, 95%CI: 0.04 to 0.12). For example, this translates into a mean difference of 1.3 points of MSSS between patients living in Madrid and Copenhagen. No such association was observed in latitudes <40° (β=-0.02, 95% CI:-0.06 to 0.03). The overall disability accrual was faster in those with a lower level of estimated UVB exposure before the age of 6 (β=- 0.5, 95% CI: -0.6 to 0.4) and 18 years (β=- 0.6, 95%CI:-0.7 to 0.4), as well as with lower life-time UVB exposure at the time of disability assessment (β=-1.0, 95%CI:-1.1 to 0.9).

DISCUSSION

In temperate zones, MS severity is associated with latitude. This association is mainly, but not exclusively, driven by UVB exposure contributing to both MS susceptibility and severity.

Cumulative Roles for Epstein-Barr Virus, Human Endogenous Retroviruses, and Human Herpes Virus-6 in Driving an Inflammatory Cascade Underlying MS Pathogenesis

Roles for viral infections and aberrant immune responses in driving localized neuroinflammation and neurodegeneration in multiple sclerosis (MS) are the focus of intense research. Epstein-Barr virus (EBV), as a persistent and frequently reactivating virus with major immunogenic influences and a near 100% epidemiological association with MS, is considered to play a leading role in MS pathogenesis, triggering localized inflammation near or within the central nervous system (CNS). This triggering may occur directly via viral products (RNA and protein) and/or indirectly via antigenic mimicry involving B-cells, T-cells and cytokine-activated astrocytes and microglia cells damaging the myelin sheath of neurons. The genetic MS-risk factor HLA-DR2b (DRB1*1501β, DRA1*0101α) may contribute to aberrant EBV antigen-presentation and anti-EBV reactivity but also to mimicry-induced autoimmune responses characteristic of MS. A central role is proposed for inflammatory EBER1, EBV-miRNA and LMP1 containing exosomes secreted by viable reactivating EBV+ B-cells and repetitive release of EBNA1-DNA complexes from apoptotic EBV+ B-cells, forming reactive immune complexes with EBNA1-IgG and complement. This may be accompanied by cytokine- or EBV-induced expression of human endogenous retrovirus-W/-K (HERV-W/-K) elements and possibly by activation of human herpesvirus-6A (HHV-6A) in early-stage CNS lesions, each contributing to an inflammatory cascade causing the relapsing-remitting neuro-inflammatory and/or progressive features characteristic of MS. Elimination of EBV-carrying B-cells by antibody- and EBV-specific T-cell therapy may hold the promise of reducing EBV activity in the CNS, thereby limiting CNS inflammation, MS symptoms and possibly reversing disease. Other approaches targeting HHV-6 and HERV-W and limiting inflammatory kinase-signaling to treat MS are also being tested with promising results. This article presents an overview of the evidence that EBV, HHV-6, and HERV-W may have a pathogenic role in initiating and promoting MS and possible approaches to mitigate development of the disease.

Crosstalk of Microorganisms and Immune Responses in Autoimmune Neuroinflammation: A Focus on Regulatory T Cells

Regulatory T cells (Tregs) are the major determinant of peripheral immune tolerance. Many Treg subsets have been described, however thymus-derived and peripherally induced Tregs remain the most important subpopulations. In multiple sclerosis, a prototypical autoimmune disorder of the central nervous system, Treg dysfunction is a pathogenic hallmark. In contrast, induction of Treg proliferation and enhancement of their function are central immune evasion mechanisms of infectious pathogens. In accordance, Treg expansion is compartmentalized to tissues with high viral replication and prolonged in chronic infections. In friend retrovirus infection, Treg expansion is mainly based on excessive interleukin-2 production by infected effector T cells. Moreover, pathogens seem also to enhance Treg functions as shown in human immunodeficiency virus infection, where Tregs express higher levels of effector molecules such as cytotoxic T-lymphocyte-associated protein 4, CD39 and cAMP and show increased suppressive capacity. Thus, insights into the molecular mechanisms by which intracellular pathogens alter Treg functions might aid to find new therapeutic approaches to target central nervous system autoimmunity. In this review, we summarize the current knowledge of the role of pathogens for Treg function in the context of autoimmune neuroinflammation. We discuss the mechanistic implications for future therapies and provide an outlook for new research directions.

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.

Gender and the Sex Hormone Estradiol Affect Multiple Sclerosis Risk Gene Expression in Epstein-Barr Virus-Infected B Cells

Multiple Sclerosis (MS) is a complex immune-mediated disease of the central nervous system. Treatment is based on immunomodulation, including specifically targeting B cells. B cells are the main host for the Epstein-Barr Virus (EBV), which has been described as necessary for MS development. Over 200 genetic loci have been identified as increasing susceptibility to MS. Many MS risk genes have altered expression in EBV infected B cells, dependent on the risk genotype, and are themselves regulated by the EBV transcription factor EBNA2. Females are 2-3 times more likely to develop MS than males. We investigated if MS risk loci might mediate the gender imbalance in MS. From a large public dataset, we identified gender-specific associations with EBV traits, and MS risk SNP/gene pairs with gender differences in their associations with gene expression. Some of these genes also showed gender differences in correlation of gene expression level with Estrogen Receptor 2. To test if estrogens may drive these gender specific differences, we cultured EBV infected B cells (lymphoblastoid cell lines, LCLs), in medium depleted of serum to remove the effects of sex hormones as well as the estrogenic effect of phenol red, and then supplemented with estrogen (100 nM estradiol). Estradiol treatment altered MS risk gene expression, LCL proliferation rate, EBV DNA copy number and EBNA2 expression in a sex-dependent manner. Together, these data indicate that there are estrogen-mediated gender-specific differences in MS risk gene expression and EBV functions. This may in turn contribute to gender differences in host response to EBV and to MS susceptibility.

The CD8 T Cell-Epstein-Barr Virus-B Cell Trialogue: A Central Issue in Multiple Sclerosis Pathogenesis

The cause and the pathogenic mechanisms leading to multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system (CNS), are still under scrutiny. During the last decade, awareness has increased that multiple genetic and environmental factors act in concert to modulate MS risk. Likewise, the landscape of cells of the adaptive immune system that are believed to play a role in MS immunopathogenesis has expanded by including not only CD4 T helper cells but also cytotoxic CD8 T cells and B cells. Once the key cellular players are identified, the main challenge is to define precisely how they act and interact to induce neuroinflammation and the neurodegenerative cascade in MS. CD8 T cells have been implicated in MS pathogenesis since the 80's when it was shown that CD8 T cells predominate in MS brain lesions. Interest in the role of CD8 T cells in MS was revived in 2000 and the years thereafter by studies showing that CNS-recruited CD8 T cells are clonally expanded and have a memory effector phenotype indicating in situ antigen-driven reactivation. The association of certain MHC class I alleles with MS genetic risk implicates CD8 T cells in disease pathogenesis. Moreover, experimental studies have highlighted the detrimental effects of CD8 T cell activation on neural cells. While the antigens responsible for T cell recruitment and activation in the CNS remain elusive, the high efficacy of B-cell depleting drugs in MS and a growing number of studies implicate B cells and Epstein-Barr virus (EBV), a B-lymphotropic herpesvirus that is strongly associated with MS, in the activation of pathogenic T cells. This article reviews the results of human studies that have contributed to elucidate the role of CD8 T cells in MS immunopathogenesis, and discusses them in light of current understanding of autoreactivity, B-cell and EBV involvement in MS, and mechanism of action of different MS treatments. Based on the available evidences, an immunopathological model of MS is proposed that entails a persistent EBV infection of CNS-infiltrating B cells as the target of a dysregulated cytotoxic CD8 T cell response causing CNS tissue damage.

Role of Viral Infections in Multiple Sclerosis Pathogenesis among Indian Population

Background

The role of viral infections in multiple sclerosis (MS) pathogenesis is unclear.

Objective

Certain neurotropic viruses previously linked with MS among white population were studied including Epstein-Barr virus, human herpesvirus-6 (HHV-6) and MS-associated retrovirus (MSRV).

Material and Methods

Sixty-two MS patients (37 had a recent clinical relapse) and 65 controls with other neurological disorders were included. Blood and cerebrospinal fluid (CSF) samples were obtained and processed with the primary objective of determining whether there was intrathecal multiplication of viruses under study (EBV, HHV6 A and B and human endogenous retrovirus) or a breach in blood-brain barrier associated with viral presence in both peripheral blood and CSF.

Results

Evidence of breach in blood-brain barrier was seen in 86.5% of patients as evidenced by abnormal CSF/serum albumin index and or MRI. EBV nuclear antigen (EBNA1 IgG) was seen in 89% of MS patients and 58% controls (P = <0.001). However, HHV6 IgG was similar in both groups (85% versus 81%; P = 0.45). In affinity immunoblotting reaction intrathecal IgG synthesis against EBNA1 antigen was demonstrable in 26% (16/62) of patients and none against HHV6. A subset of patients showed significant elevation in mean copy number of plasma EBV DNA during relapse and there was a trend for the same among patients harboring HHV-6B. No evidence of isolated intrathecal viral presence or multiplication was seen.

Conclusions

The results of our study suggest that viruses studied namely EBV and HHV6 have a role in triggering relapses through a peripheral mechanism, rather than a direct role through intrathecal multiplication.

Herpesviruses and the hidden links to Multiple Sclerosis neuropathology

Herpesviruses like Epstein-Barr virus, human herpesvirus (HHV)-6, HHV-1, VZV, and human endogenous retroviruses, have an age-old clinical association with multiple sclerosis (MS). MS is an autoimmune disease of the nervous system wherein the myelin sheath deteriorates. The most popular mode of virus mediated immune system manipulation is molecular mimicry. Numerous herpesvirus antigens are similar to myelin proteins. Other mechanisms described here include the activity of cytokines and autoantibodies produced by the autoreactive T and B cells, respectively, viral déjà vu, epitope spreading, CD46 receptor engagement, impaired remyelination etc. Overall, this review addresses the host-parasite association of viruses with MS.

The role of Epstein-Barr virus in the etiology of multiple sclerosis: a current review

Introduction: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system. While its exact etiology is unknown, it is generally believed that MS is caused by environmental triggers in genetically predisposed individuals. Strong and consistent evidence suggests a key role of Epstein-Barr virus (EBV), a B lymphotropic human gammaherpesvirus, in the etiology of MS. Areas covered: This review summarizes recent developments in the field of EBV and MS with a focus on potential mechanisms underlying the role of EBV in MS. PubMed was searched for the terms 'Epstein-Barr virus' and 'multiple sclerosis'. Expert opinion: The current evidence is compatible with the working hypothesis that MS is a rare complication of EBV infection. Under the premise of a causative role of EBV in MS, it needs to be postulated that EBV causes a specific, and likely persistent, change(s) that is necessarily required for the development of MS. However, although progress has been made, the nature of that change and thus the precise mechanism explaining the role of EBV in MS remain elusive. The mechanism of EBV in MS therefore is a pressing question, whose clarification may substantially advance the pathophysiological understanding, rational therapies, and prevention of MS.

Search for viral agents in cerebrospinal fluid in patients with multiple sclerosis using real-time PCR and metagenomics

Multiple sclerosis (MS) is a chronic, immune-mediated demyelinating disease of the central nervous system of unclear etiology, but there is some evidence that viral infections could be responsible for triggering autoimmune mechanisms against myelin. We searched for viral RNA and DNA in cerebrospinal fluid (CSF) of 34 MS patients and 13 controls using RT-PCR/PCR against common neurotropic viruses. In addition, shotgun DNA- and RNA-based metagenomics were done in 13 MS patients and 4 controls. Specific quantitative real-time RT-PCR/PCR testing revealed the presence of viral nucleic acid in seven (20.59%) MS patients and in one (7.69%) control patient. In MS patients the most frequently detected was human herpesvirus type 6 (HHV-6; 3 cases; 8.82%); followed by Epstein-Barr virus (EBV; 2 cases; 5.88%), varicella zoster virus (VZV; 1 case; 2.94%) and Enterovirus (EV; 1 case; 2.94%). The single identified virus among controls was EBV (7.69%). DNA and RNA metagenomic assays did not identify any known eukaryotic viruses even though three of the analyzed samples were low-level positive by specific quantitative real-time PCR. In conclusion, we detected the presence of Herpesviridae and occasionally Enteroviridae in CSF from patients with MS but their prevalence was not significantly higher than among controls. Metagenomic analysis seems to be less sensitive than real-time RT-PCR/PCR and it did not detect any potential viral pathogens.

From Anti-EBV Immune Responses to the EBV Diseasome via Cross-reactivity

Sequence analyses highlight a massive peptide sharing between immunoreactive Epstein-Barr virus (EBV) epitopes and human proteins that—when mutated, deficient or improperly functioning—associate with tumorigenesis, diabetes, lupus, multiple sclerosis, rheumatoid arthritis, and immunodeficiencies, among others. Peptide commonality appears to be the molecular platform capable of linking EBV infection to the vast EBV-associated diseasome via cross-reactivity and questions the hypothesis of the “negative selection” of self-reactive lymphocytes. Of utmost importance, this study warns that using entire antigens in anti-EBV immunotherapies can associate with autoimmune manifestations and further supports the concept of peptide uniqueness for designing safe and effective anti-EBV immunotherapies.

An Absence of Epstein-Barr Virus Reactivation and Associations with Disease Activity in People with Multiple Sclerosis Undergoing Therapeutic Hookworm Vaccination

Background: Epstein–Barr virus (EBV) infection is strongly associated with multiple sclerosis (MS). Helminth infection can downregulate antiviral immune responses, potentially protecting against MS, but with a theoretical risk for reactivating latent EBV infection. Objective: To investigate parameters of EBV infection and their relationship with disease activity in people with MS (PwMS) therapeutically vaccinated with Necator americanus (hookworm). Methods: Sequential serum samples from 51 PwMS; 26 therapeutically infected (25 larvae) with N. americanus and 25 controls were tested for EBV virus capsid antigen (VCA) IgG and IgM, EBV nuclear antigen-1 (EBNA-1) IgG, and EBV early antigen (EA) IgG. Disease activity was assessed by periodic MRI. Significance was set at p < 0.05. Results: All PwMS were EBV VCA IgG and EBNA-1 IgG positive, and 35.2% were EBV EA IgG positive. EBV antibody levels were generally stable, and EBV reactivation in PwMS was not demonstrated by significant increases in IgG titre over 12 months. Disease activity was most frequent in PwMS possessing high levels of EBV VCA IgG (>600 units/mL) or EBNA-1 IgG (>150 units/mL); however, there was no association with hookworm treatment. Interpretation: Therapeutic hookworm vaccination was not associated with EBV reactivation. Multiple sclerosis disease activity was associated with high levels of EBV VCA IgG or EBNA-1 IgG.

Antibodies from Multiple Sclerosis Brain Identified Epstein-Barr Virus Nuclear Antigen 1 & 2 Epitopes which Are Recognized by Oligoclonal Bands

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS), the etiology of which is poorly understood. The most common laboratory abnormality associated with MS is increased intrathecal immunoglobulin G (IgG) synthesis and the presence of oligoclonal bands (OCBs) in the brain and cerebrospinal fluid (CSF). However, the major antigenic targets of these antibody responses are unknown. The risk of MS is increased after infectious mononucleosis (IM) due to EBV infection, and MS patients have higher serum titers of anti-EBV antibodies than control populations. Our goal was to identify disease-relevant epitopes of IgG antibodies in MS; to do so, we screened phage-displayed random peptide libraries (12-mer) with total IgG antibodies purified from the brain of a patient with acute MS. We identified and characterized the phage peptides for binding specificity to intrathecal IgG from patients with MS and from controls by ELISA, phage-mediated Immuno-PCR, and isoelectric focusing. We identified two phage peptides that share sequence homologies with EBV nuclear antigens 1 and 2 (EBNA1 and EBNA2), respectively. The specificity of the EBV epitopes found by panning with MS brain IgG was confirmed by ELISA and competitive inhibition assays. Using a highly sensitive phage-mediated immuno-PCR assay, we determined specific bindings of the two EBV epitopes to IgG from CSF from 46 MS and 5 inflammatory control (IC) patients. MS CSF IgG have significantly higher bindings to EBNA1 epitope than to EBNA2 epitope, whereas EBNA1 and EBNA2 did not significantly differ in binding to IC CSF IgG. Further, the EBNA1 epitope was recognized by OCBs from multiple MS CSF as shown in blotting assays with samples separated by isoelectric focusing. The EBNA1 epitope is reactive to MS intrathecal antibodies corresponding to oligoclonal bands. This reinforces the potential role of EBV in the etiology of MS.

Graphical abstract

Recombinant Epstein-Barr virus glycoprotein 350 as a serological antigen

Epstein-Barr virus (EBV) glycoprotein 350 (gp350) is the most abundant glycoprotein expressed on the EBV envelope, the major target for neutralizing antibodies and also essential for virion attachment to B lymphocytes. Several studies have addressed EBV gp350 as a vaccine candidate, but less commonly as a potential antigen for serological assays. The aim of the current study was to develop a diagnostic tool to quantify EBV gp350-specific IgG in previously EBV-infected individuals. A construct encoding the extracellular domain of EBV gp350 (amino acid (aa) 1-860) was developed for expression in Chinese hamster ovary cells. Serum samples (n = 360) with known IgG serostatus against viral capsid antigen (VCA) and Epstein-Barr nuclear antigen 1 (EBNA1) were divided into three groups based on the differences in their serostatus: VCA + EBNA1+ (n = 120), VCA + EBNA1- (n = 120) and VCA-EBNA1- (n = 120). The samples were analyzed by indirect ELISA using recombinant EBV gp350 aa 1-860 as antigen. A clear majority, 108 of the 120 VCA + EBNA1+ samples, had detectable EBV gp350-specific IgG. Of the 120 VCA + EBNA1- samples, 79 had detectable EBV gp350-specific IgG. Only 2 of the 120 VCA-EBNA1- samples had detectable EBV gp350-specific IgG. The results reported here show that use of the EBV gp350 aa 1-860 ELISA can serve as a sensitive method for EBV-specific IgG detection in serum samples.

Vitamin D, smoking, EBV, and long-term cognitive performance in MS: 11-year follow-up of BENEFIT

OBJECTIVE

To investigate whether vitamin D, smoking, and anti-Epstein-Barr virus (EBV) antibody concentrations predict long-term cognitive status and neuroaxonal injury in multiple sclerosis (MS).

METHODS

This study was conducted among 278 patients with clinically isolated syndrome who participated in the clinical trial BENEFIT (Betaferon/Betaseron in Newly Emerging Multiple Sclerosis for Initial Treatment) and completed the 11-year assessment (BENEFIT-11). We measured serum 25-hydroxyvitamin-D (25(OH)D), cotinine (smoking biomarker), and anti-Epstein-Barr virus nuclear antigen 1 (EBNA-1) immunoglobulin G (IgG) at baseline and at months 6, 12, and 24 and examined whether these biomarkers contributed to predict Paced Auditory Serial Addition Test (PASAT)-3 scores and serum neurofilament light chain (NfL) concentrations at 11 years. Linear and logistic regression models were adjusted for sex, baseline age, treatment allocation, steroid treatment, multifocal symptoms, T2 lesions, and body mass index.

RESULTS

Higher vitamin D predicted better, whereas smoking predicted worse cognitive performance. A 50-nmol/L higher mean 25(OH)D in the first 2 years was related to 65% lower odds of poorer PASAT performance at year 11 (95% confidence intervals [95% CIs]: 0.14-0.89). Standardized PASAT scores were lower in smokers and heavy smokers than nonsmokers (p _trend = 0.026). Baseline anti-EBNA-1 IgG levels did not predict cognitive performance (p _trend = 0.88). Associations with NfL concentrations at year 11 corroborated these findings-a 50-nmol/L higher mean 25(OH)D in the first 2 years was associated with 20% lower NfL (95% CI: -36% to 0%), whereas smokers had 20% higher NfL levels than nonsmokers (95% CI: 2%-40%). Anti-EBNA-1 antibodies were not associated with NfL.

CONCLUSIONS

Lower vitamin D and smoking after clinical onset predicted worse long-term cognitive function and neuronal integrity in patients with MS.

Higher EBV response is associated with more severe gray matter and lesion pathology in relapsing multiple sclerosis patients: A case-controlled magnetization transfer ratio study

BACKGROUND

Epstein-Barr virus (EBV) infection has been associated with higher clinical activity and risk of multiple sclerosis (MS).

OBJECTIVE

To evaluate associations between EBV-specific humoral response and magnetization transfer ratio (MTR)-derived measure in MS patients and healthy controls (HCs).

METHODS

The study included 101 MS patients (69 relapsing-remitting multiple sclerosis (RRMS) and 32 secondary-progressive multiple sclerosis (SPMS)) and 41 HCs who underwent clinical, serological, and magnetic resonance imaging (MRI) investigations. MTR values of T1 or T2 lesion volume (LV), normal-appearing (NA) brain tissue (NABT), gray matter (NAGM), and white matter (NAWM) were obtained. Enzyme-linked immunosorbent assay was used to quantify EBV antibody levels. Partial correlations corrected for MRI strength were used, and Benjamini-Hochberg-adjusted p-values < 0.05 were considered significant.

RESULTS

MS patients had significantly higher anti-EBV nuclear antigen-1 (EBNA-1) titer when compared to HCs (107.9 U/mL vs 27.8 U/mL, p < 0.001). Within the MS group, higher serum anti-EBNA-1 titer was significantly correlated with lower T1-LV MTR (r = -0.287, p = 0.035). Within the RRMS group, higher serum anti-EBNA-1 titer was associated with T1-LV MTR (r = -0.524, p = 0.001) and NAGM MTR (r = -0.308, p = 0.043). These associations were not present in HCs or SPMS patients.

CONCLUSION

Greater EBV humoral response is associated with lower GM MTR changes and focal destructive lesion pathology in RRMS patients.

Infections, Vaccines and Autoimmunity: A Multiple Sclerosis Perspective

Background: Multiple sclerosis (MS) is a chronic neuroinflammatory and neurodegenerative disease that is associated with multiple environmental factors. Among suspected susceptibility events, studies have questioned the potential role of overt viral and bacterial infections, including the Epstein Bar virus (EBV) and human endogenous retroviruses (HERV). Furthermore, the fast development of immunomodulatory therapies further questions the efficacy of the standard immunization policies in MS patients. Topics reviewed: This narrative review will discuss the potential interplay between viral and bacterial infections and their treatment on MS susceptibility and disease progression. In addition, the review specifically discusses the interactions between MS pathophysiology and vaccination for hepatitis B, influenza, human papillomavirus, diphtheria, pertussis, and tetanus (DTP), and Bacillus Calmette-Guerin (BCG). Data regarding potential interaction between MS disease modifying treatment (DMT) and vaccine effectiveness is also reviewed. Moreover, HERV-targeted therapies such as GNbAC1 (temelimab), EBV-based vaccines for treatment of MS, and the current state regarding the development of T-cell and DNA vaccination are discussed. Lastly, a reviewing commentary on the recent 2019 American Academy of Neurology (AAN) practice recommendations regarding immunization and vaccine-preventable infections in the settings of MS is provided. Conclusion: There is currently no sufficient evidence to support associations between standard vaccination policies and increased risk of MS. MS patients treated with immunomodulatory therapies may have a lower benefit from viral and bacterial vaccination. Despite their historical underperformance, new efforts in creating MS-based vaccines are currently ongoing. MS vaccination programs follow the set back and slow recovery which is widely seen in other fields of medicine.

Cytomegalovirus and Epstein-Barr Virus Associations with Neurological Diseases and the Need for Vaccine Development

Herpesviruses have been isolated from a wide range of hosts including humans—for which, nine species have been designated. The human herpesviruses are highly host adapted and possess the capacity for latency, allowing them to survive in the host for life, effectively hidden from the immune system. This ability of human herpesviruses to modulate the host immune response poses particular challenges for vaccine development but at the same time proves attractive for the application of human herpesvirus vaccines to certain spheres of medicine. In this review, congenital cytomegalovirus (CMV) infection and hearing loss will be described followed by a comment on the status of current vaccine development. Secondly, the association of Epstein–Barr virus (EBV) infection with multiple sclerosis (MS) and how EBV vaccination may be of benefit will then be discussed. Prevention of congenital CMV by vaccination is an attractive proposition and several vaccines have been evaluated for potential use. Particularly challenging for the development of CMV vaccines are the needs to prevent primary infection, reinfection, and reactivation at the same time as overcoming the capacity of the virus to generate highly sophisticated immunomodulatory mechanisms. Cost and the practicalities of administering potential vaccines are also significant issues, particularly for low- and middle-income countries, where the burden of disease is greatest. An effective EBV vaccine that could prevent the 200,000 new EBV-associated malignancies which occur globally each year is not currently available. There is increasing interest in developing EBV vaccines to prevent MS and, in view of the association of infectious mononucleosis with MS, reducing childhood infectious mononucleosis is a potential intervention. Currently, there is no licensed EBV vaccine and, in order to progress the development of EBV vaccines for preventing MS, a greater understanding of the association of EBV with MS is required.

Teriflunomide's effect on humoral response to Epstein-Barr virus and development of cortical gray matter pathology in multiple sclerosis

BACKGROUND

Teriflunomide has been shown to slow cortical gray matter (GM) atrophy in patients with multiple sclerosis (MS). Previous work showed that higher levels of Epstein-Barr virus (EBV) are associated with greater development of cortical pathology in MS.

OBJECTIVES

To investigate whether the effect of teriflunomide on cortical volume loss in relapsing MS patients may be associated with the change in humoral response to EBV.

METHODS

This was a prospective, observational, single-blinded, longitudinal study of 30 relapsing MS patients, who started treatment with teriflunomide, and 20 age- and sex-matched healthy controls (HCs). Subjects were assessed at baseline, 6 and 12 months with clinical, MRI and EBV examinations. MRI outcomes included percent changes in cortical, GM, deep GM and whole brain volumes. Serum samples were analyzed for IgG antibodies titers against EBV viral capsid antigen (VCA) and nuclear antigen-1 (EBNA-1).

RESULTS

There were no significant differences in anti-VCA and anti-EBNA-1 IgG titers between MS patients and HC at baseline. However, over the 12-month follow-up, MS patients experienced a greater decrease in anti-EBNA-1 (-35.1, p = .003) and anti-VCA (-15.9, p = .05) IgG titers, whereas no significant changes were observed in HCs (-3.7 and -1.6, respectively). MS patients who showed the highest decrease in anti-EBV VCA and EBNA-1 IgG titers from baseline to follow-up, developed less cortical (p < .001 and p = .02) and GM volume loss (p = .004 for both), respectively.

CONCLUSIONS

Teriflunomide's effect on slowing cortical and GM volume loss may be mediated by its effect on altering humoral response to EBV.

Differential serostatus of Epstein-Barr virus in Iranian MS patients with various clinical patterns

Background: Epidemiological evidence suggests a role of Epstein-Barr virus (EBV) in triggering the pathogenesis of Multiple Sclerosis (MS). The aim of this study was to assess the EBV-specific antibodies in MS patients with various clinical patterns and their association with the production of IFN-γ, IL-12, and IL-4 cytokines compared with healthy individuals.

Methods: We measured EBNA-1 IgG, VCA IgG, and production of IFN-γ, IL-12 and IL-4 cytokines in patients with different clinical patterns and healthy controls using ELISA method.

Results: There was a higher titer of anti-EBV antibodies in MS patients compared to healthy controls. SPMS patients generated higher EBNA-1 levels than those with RRMS and PPMS patients whereas; the level of VCA IgG was higher in the RRMS patients than PPMS. In PPMS patients, a significant increase was found in IFN-γ and IL-12 cytokines compared to other subtypes, whereas IL-4 cytokine had a decreased level compared to RRMS patients. Higher anti-EBV antibodies are associated with increased IL-12 cytokine in RRMS patients. However, no significant correlation was found between these antibodies and other secreted cytokines.

Conclusion: EBV infection is one of the strong risk factors for MS. Acting on these factors could be useful to decrease the incidence and disease exacerbation of MS. Study of the antibody levels to EBV virus could be useful for evaluating MS risk score in each clinical subtypes.

The role of Epstein-Barr virus in multiple sclerosis: from molecular pathophysiology to in vivo imaging

Multiple sclerosis (MS) is a disease of the central nervous system characterized by inflammation, demyelination, and neuronal damage. Environmental and genetic factors are associated with the risk of developing MS, but the exact cause still remains unidentified. Epstein-Barr virus (EBV), vitamin D, and smoking are among the most well-established environmental risk factors in MS. Infectious mononucleosis, which is caused by delayed primary EBV infection, increases the risk of developing MS. EBV may also contribute to MS pathogenesis indirectly by activating silent human endogenous retrovirus-W. The emerging B-cell depleting therapies, particularly anti-CD20 agents such as rituximab, ocrelizumab, as well as the fully human ofatumumab, have shown promising clinical and magnetic resonance imaging benefit. One potential effect of these therapies is the depletion of memory B-cells, the primary reservoir site where EBV latency occurs. In addition, EBV potentially interacts with both genetic and other environmental factors to increase susceptibility and disease severity of MS. This review examines the role of EBV in MS pathophysiology and summarizes the recent clinical and radiological findings, with a focus on B-cells and in vivo imaging. Addressing the potential link between EBV and MS allows the better understanding of MS pathogenesis and helps to identify additional disease biomarkers that may be responsive to B-cell depleting intervention.

DNA hydroxymethylation changes in response to spinal cord damage in a multiple sclerosis mouse model

AIM

Roles of DNA 5-hydroxymethylcytosine (5hmC) in myelin repair were investigated in an experimental autoimmune encephalomyelitis (EAE) mouse model via its regulation on BDNF.

METHODS

DNA 5hmC level and its limiting enzymes were detected in EAE mice.

RESULTS

Global 5hmC modification, Tet1 and Tet2 significantly decreased in the spinal cord tissues of EAE mice. BDNF protein and mRNA decreased and were highly associated with BDNF 5hmC. Vitamin C, a Tet co-factor, increased global DNA 5hmC and reduced the neurological deficits at least by increasing BDNF 5hmC modification and protein levels.

CONCLUSION

Tet protein-mediated 5hmC modifications represent a critical target involved in EAE-induced myelin damage. Targeting epigenetic modification may be a therapeutic strategy for multiple sclerosis.