Longitudinal analysis reveals high prevalence of Epstein-Barr virus associated with multiple sclerosis

Neuronal guidance signaling in neurodegenerative diseases: Key regulators that function at neuron-glia and neuroimmune interfaces

The nervous system processes a vast amount of information, performing computations that underlie perception, cognition, and behavior. During development, neuronal guidance genes, which encode extracellular cues, their receptors, and downstream signal transducers, organize neural wiring to generate the complex architecture of the nervous system. It is now evident that many of these neuroguidance cues and their receptors are active during development and are also expressed in the adult nervous system. This suggests that neuronal guidance pathways are critical not only for neural wiring but also for ongoing function and maintenance of the mature nervous system. Supporting this view, these pathways continue to regulate synaptic connectivity, plasticity, and remodeling, and overall brain homeostasis throughout adulthood. Genetic and transcriptomic analyses have further revealed many neuronal guidance genes to be associated with a wide range of neurodegenerative and neuropsychiatric disorders. Although the precise mechanisms by which aberrant neuronal guidance signaling drives the pathogenesis of these diseases remain to be clarified, emerging evidence points to several common themes, including dysfunction in neurons, microglia, astrocytes, and endothelial cells, along with dysregulation of neuron-microglia-astrocyte, neuroimmune, and neurovascular interactions. In this review, we explore recent advances in understanding the molecular and cellular mechanisms by which aberrant neuronal guidance signaling contributes to disease pathogenesis through altered cell-cell interactions. For instance, recent studies have unveiled two distinct semaphorin-plexin signaling pathways that affect microglial activation and neuroinflammation. We discuss the challenges ahead, along with the therapeutic potentials of targeting neuronal guidance pathways for treating neurodegenerative diseases. Particular focus is placed on how neuronal guidance mechanisms control neuron-glia and neuroimmune interactions and modulate microglial function under physiological and pathological conditions. Specifically, we examine the crosstalk between neuronal guidance signaling and TREM2, a master regulator of microglial function, in the context of pathogenic protein aggregates. It is well-established that age is a major risk factor for neurodegeneration. Future research should address how aging and neuronal guidance signaling interact to influence an individual's susceptibility to various late-onset neurological diseases and how the progression of these diseases could be therapeutically blocked by targeting neuronal guidance pathways.

Virus-specific antibody responses in severe acute respiratory syndrome coronavirus 2-infected and vaccinated individuals

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can have a serious course with many complications, especially in immunocompromised individuals. In such persons, other latent virus infections may contribute to disease pathology, in particular viruses which infect immune cells such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV).

METHODS

In this study, serology-based assays were conducted to analyse antibody responses to SARS-CoV-2 spike protein (SP), EBV Epstein-Barr nuclear antigen (EBNA)-1 and CMV phosphoprotein (pp)52 in naturally SARS-CoV-2-infected individuals, non-infected healthy controls (HCs) and vaccinated healthy controls (VHCs) to identify an association between SARS-CoV-2 antibodies and EBV and CMV antibodies in order to determine whether latent EBV and CMV infected individuals are more prone to become infected with SARS-CoV-2. Moreover, SARS-CoV-2, EBV, and CMV antibody responses were characterized in serum from patients with relapsing-remitting multiple sclerosis (RRMS), a chronic inflammatory disease strongly associated with EBV infections, to determine whether the serologic virus antibody profile varies in immunocompromised RRMS individuals upon SARS-CoV-2 vaccinations compared to VHCs.

RESULTS

Significantly elevated SP IgG, IgM and IgA levels were identified in SARS-CoV-2-infected immunocompetent individuals when compared to non-infected HCs. However, no correlation was found to serum antibodies between SARS-CoV-2, EBV, and CMV in individuals infected with SARS-CoV-2 and in VHCs, suggesting that latent infections with neither EBV nor CMV associates to SARS-CoV-2 infection. Moreover, no significant difference in SP IgG, IgA and IgM levels was observed between vaccinated RRMS patients and VHCs, indicating that the immune system of immune deficient RRMS patients and VHCs respond identical to SARS-CoV-2 vaccinations.

CONCLUSION

Collectively, SARS-CoV-2 SP antibody levels reflect the vaccination and infection history and do not associate with EBV and CMV serostatus.

Clinical characteristics and immunotherapy efficacy in autoimmune-associated benign epilepsy with centrotemporal spikes: A prospective cohort study

INTRODUCTION

Benign Epilepsy with Centrotemporal Spikes (BECTS) is the most common form of focal epilepsy in pediatric patients. In clinical practice, immune dysregulation and neuroinflammation have been observed in a subset of patients with BECTS harboring latent Herpesviridae infections, including the Epstein-Barr Virus (EBV) and Human Cytomegalovirus (CMV). Therefore, the present study aimed to explore the correlation between clinical characteristics and immune dysregulation in autoimmunity-associated BECTS and latent viral or Mycoplasma infections.

METHOD

Fourteen pediatric patients diagnosed with autoimmunity-associated BECTS were prospectively enrolled and underwent assessment of their presentations and etiological and immunological indicators. Further, we evaluated the effectiveness and safety of specific immune therapies (intravenous methylprednisolone and/or intravenous immunoglobulin). Therapy efficacy was determined by a reduction in Rolandic spikes on electroencephalogram recordings and seizure frequency. Potential risk factors were assessed through a retrospective comparative analysis with a control group comprising 46 patients diagnosed with cryptogenic BECTS.

RESULT

The autoimmunity-associated BECTS cohort demonstrated a higher likelihood of cognitive impairment, ADHD, psychiatric symptoms, and atypical BECTS; required a greater number of anti-seizure medications (ASMs); and experienced longer delays from symptom onset to hospital admission. The prevalence of CMV infection was also found to be significantly higher in the autoimmune disease group than in the control group. Elevated levels of IL-6, IgG, and Complement C3 were observed in the sera of both infected and non-infected children with BECTS. Atypical BECTS and Bilateral Rolandic spikes in EEG were identified as key risk factors for autoimmunity-associated BECTS. Following immunotherapy (intravenous methylprednisolone and/or intravenous immunoglobulin), a substantial reduction in seizure frequency and accumulated spike-wave index (AccSWI) was observed.

CONCLUSION

These findings support the hypothesis that autoimmune mechanisms contribute to the pathogenesis of selected BECTS cases. Latent viral infections such as CMV may serve as potential triggers. Atypical presentations of BECTS, with Bilateral Rolandic spikes in EEG, indicate the possibility of an autoimmune-associated trigger. Immunotherapy appears to offer therapeutic benefits to patients with autoimmunity-associated BECTS.

CLINICAL TRIAL REGISTRATION

This single-center, longitudinal observational study (XH-16-029/NCT02969213) included pediatric patients diagnosed with epilepsy.

Understanding EBV infection and EBV-associated lymphomas in children

The Epstein-Barr virus (EBV) infects over 90 % of the human population, often behaving as a harmless passenger in most hosts. However, since 1997, it has been classified as a group 1 carcinogen by the International Agency for Research on Cancer (IARC) due to its causal association with several malignancies. Most studies on EBV primary infection and EBV-associated lymphomas have been performed in adults from developed countries. The complex interplay between age of acquisition and symptomatic versus asymptomatic infection is related to the subsequent risk of EBV-associated cancers or autoimmune diseases. This review discusses some characteristics of EBV infection and EBV-associated lymphomas in children from low- and middle-income regions, with a focus on the local immune response.

The intestinal microbiome in type 1 diabetes: bridging early childhood exposures with translational advances

Type 1 diabetes (T1D) results from T cell-mediated destruction of pancreatic β-cells, requiring lifelong insulin therapy and glycemic monitoring. While genetic risk, particularly HLA class II, is well established, rising T1D incidence and earlier onset suggest environmental modifiers. Mouse models show that microbiome alterations influence β-cell autoimmunity, and human studies link microbiome composition to T1D, though specific microbial regulators remain unidentified. We examine host-microbiome interactions, including studies implicating enteroviruses in modulating islet autoimmunity. Mechanistic discoveries of microbial effects on diabetes have emerged from mouse model studies. We consider clinical applications, including microbiota-targeted therapies and biomarkers of microbiome-immune crosstalk. Future research should integrate microbial, genetic, environmental, and immune data using multi-omic approaches. Collaborative efforts combining immunology, microbiology, and clinical metadata will drive discovery and precision medicine in T1D.

Molecular mimicry in the pathogenesis of autoimmune rheumatic diseases

Autoimmune rheumatic diseases (ARDs) are a heterogeneous group of conditions characterized by excessive and misdirected immune responses against the body's own musculoskeletal tissues. Their exact aetiology remains unclear, with genetic, demographic, behavioural and environmental factors implicated in disease onset. One prominent hypothesis for the initial breach of immune tolerance (leading to autoimmunity) is molecular mimicry, which describes structural or sequence similarities between human and microbial proteins (mimotopes). This similarity can lead to cross-reactive antibodies and T-cell receptors, resulting in an immune response against autoantigens. Both commensal microbes in the human microbiome and pathogens can trigger molecular mimicry, thereby potentially contributing to the onset of ARDs. In this review, we focus on the role of molecular mimicry in the onset of rheumatoid arthritis and systemic lupus erythematosus. Moreover, implications of molecular mimicry are also briefly discussed for ankylosing spondylitis, systemic sclerosis and myositis.

Immunology of multiple sclerosis: an update

PURPOSE OF REVIEW

The immunological processes that lead to multiple sclerosis (MS) and occur during the progressive phase of the disease are manifold and still not well understood. This review summarizes new insights on this topic that were gained through recent studies with diverse scientific approaches.

RECENT FINDINGS

While genetic risk clearly contributes to MS, external factors play a key role in its pathogenesis as well. Epstein-Barr virus infection correlates significantly with MS risk and seems to be a major causal factor. Even though our knowledge on the human gut microbiome and its connection to the central nervous system is far from being complete, several studies have proven that the gut-brain axis influences neuroinflammation and disease progression in MS. It has become much clearer that MS is not solely a T cell-mediated disease but is also strongly driven by B cells and pathogenic antibodies. Beyond the peripheral immune cells, glial cells and their interactions with neurons are important players contributing to disease activity and progression in MS.

SUMMARY

Taken together, recent publications on immunological processes in the context of MS implicate a multitude of noncanonical mechanisms that need to be further explored regarding their interplay and contribution to the degenerative course of the disease.

Hypoxia in multiple sclerosis

Low oxygen availability (hypoxia) is a prominent but poorly understood feature in multiple sclerosis (MS). Whether hypoxia causes or drives MS pathology and symptoms or whether it is a consequence of other pathological events, such as inflammation and vascular dysfunction, is unknown. Here, we summarize the available literature on the interplay between hypoxia and both pathological and symptomatic features of MS. Severe environmental hypoxia (i.e., altitude) may trigger or facilitate MS-related events, possibly by exacerbating tissue hypoxia in the central nervous system. Accordingly, increasing oxygen supply can mitigate pathological and clinical parameters in MS models. In contrast, stimulating the endogenous hypoxia response and adaptation systems by controlled exposure to hypoxia (hypoxia conditioning) renders the central nervous system more resistant to hypoxic insults, thereby attenuating pathology and symptomatology in MS models. Overlapping mechanisms likely play a role in the benefits conferred by physical activity in MS. We provide an integrative model to explain the paradoxically beneficial outcomes of both increased and decreased ambient oxygen conditions. In conclusion, controlled exposure to hypoxia, perhaps in combination with exercise, is a promising, possibly disease-course modifying therapeutic approach for MS. However, many open questions remain.

Deciphering the IgG Idiotype Network Through Proteomic Analysis of Potential Targets in SARS-CoV-2-Induced Immune Responses

The association between COVID-19 and autoimmune diseases has gained increasing recognition, yet the specific targets of SARS-CoV-2-induced IgG are currently in focus for several studies. This study aims to explore the proteomic targets of these antibodies and their potential role in autoimmunity. We utilised a human proteome microarray encompassing 23 736 unique proteins, including isoform variants and fragments, as catalogued by the Human Protein Atlas. Serum samples were analysed from four groups: healthy controls (N-exp HC), individuals vaccinated with protein-based vaccines (N-Cov Vac) and patients with moderate or severe COVID-19 (COVID-Mod and COVID-Sev). The evaluation of SARS-CoV-2-induced IgG antibodies revealed their potential to recognise multiple human proteins. Key targets included interferon alpha (IFN-α), tumour growth factor beta (TGF-β), interleukin 1 (IL-1), CXCL16, TGF-β receptors, CD34, CD47 and BCL2. The antibodies also targeted proteins from genes overexpressed in various immune cells, such as CD4+ and CD8+ T cells, γδ T cells, B cells, dendritic cells and NK cells. Reactivity was also observed with proteins specifically expressed in multiple organs, including the brain, liver, lungs and heart. Targeting patterns differed between COVID-19 patients and controls, with some proteins showing differential recognition in moderate versus severe cases. Furthermore, we evaluated the protein-protein interaction network (PPIN) of all targeted proteins and observed minimal structural homology and co-expression among the evaluated proteins, with almost no relation to the SARS-CoV-2 immune system reactome. The results suggest that the profile of SARS-CoV-2-induced IgG autoantibodies is associated with disease severity. In contrast, protein-vaccinated individuals exhibited a profile similar to non-exposed controls, suggesting that autoreactive IgG is specifically linked to active SARS-CoV-2 infection. These findings reveal a complex network of SARS-CoV-2-induced IgG idiotypes capable of targeting human proteins, not merely through simple cross-recognition of homologous proteins. This highlights the need for further investigations to determine whether they may influence COVID-19 pathophysiology and its clinical outcomes.

Long-term outcomes in patients with persistent EBV-DNA positivity after primary Epstein-Barr virus infection and clinical implications of rituximab therapy

BACKGROUND

The long-term clinical outcomes of patients with persistent EBV-DNA positivity after primary EBV infection of B cells and the clinical value of rituximab in this group of patients are unknown.

METHODS

We retrospectively analyzed patients with primary EBV-infected B cells at our center from October 2016 to July 2023. They were divided into two groups based on the presence of infectious mononucleosis. To assess disease transformation under long-term EBV exposure and the impact of rituximab on EBV-DNA clearance, we followed up and monitored the EBV-DNA changes in the conventional observation treatment subgroup and the rituximab subgroup.

RESULTS

Seventy-one patients were included in this study, and 29 of them exhibited sustained EBV-DNA positivity for over 3 months. Among them, 20 patients were classified as infectious mononucleosis (IM) group, while 9 patients belonged to the non-infectious mononucleosis (NIM) group. In the IM group, 5 out of 7 patients treated with rituximab (71.4 %) became EBV-DNA negative within one month post-treatment, while 6 of the 13 patients (46.2 %) who did not undergo rituximab treatment still remained EBV-DNA positive for over 18 months. These results suggested that rituximab treatment significantly shortened the duration required for EBV-DNA clearance. In the NIM group, 5 of the 6 patients received rituximab had EBV-associated lymphoid tissue proliferation before treatment, which occurred approximately 7 months after EBV infection was detected. Following treatment, EBV-DNA became negative in all five patients within a median of 2 months. Conversely, the three patients who did not receive rituximab treatment in the NIM group, the longest duration of EBV-DNA positivity was 16 months. Disease progression or transformation was not observed in either group of patients.

CONCLUSION

Patients with primary EBV infection of B cells are unlikely to progress to malignant disease transformation despite persistent EBV-DNA positivity. Nonetheless, there is a potential risk of chronic lymphoproliferation. Rituximab treatment is a safe and efficient method for eliminating EBV-infected B cells and achieving rapid clearance of EBV-DNA.

Epstein-Barr virus induces aberrant B cell migration and diapedesis via FAK-dependent chemotaxis pathways

Infection with the Epstein-Barr virus (EBV) is a major risk factor for the development of cancer and autoimmune disorders. The virus enters the body in the pharynx, but EBV causes disease in distant organs, including the gut and the brain. Here we show, using in vitro culture and mouse infection models, that EBV-infected B cells display features of homing cells. Infected B cells undergo migration following paracrine CCL4 release and CCR1 induction, while CCR1 deficiency inhibits migration and, unexpectedly, proliferation of infected B cells. Furthermore, migrating EBV-infected B cells undergo CCL4-dependent diapedesis, induce ICAM-1 on endothelial cells, and disrupt the integrity of endothelial barriers. Both migration and diapedesis are regulated by FAK, with FAK inhibition blocking growth and survival of EBV-transformed B cells, as well as their spreading to spleen and brain in an animal model in vivo. Moreover, IL-10 secreted by EBV-infected B cells attracts and facilitates diapedesis of EBV-negative CD52highCD11c+ B cells, which have reported autoimmune properties. Our results thus provide mechanistic insight on EBV-induced B cell dysregulation, and also hint curbing migration as a potential target for reducing the pathogenicity of EBV-infected B cells.

Comprehensive analysis of B cell repopulation in ocrelizumab-treated patients with multiple sclerosis by mass cytometry and proteomics

Ocrelizumab, an anti-CD20 antibody, depletes CD20+ B cells, which subsequently repopulate over months. Little is known about changes in other immune cell populations and molecular markers associated with B cell repopulation. Here, we performed a comprehensive characterization of immune cells from ocrelizumab-treated patients with multiple sclerosis (MS) using mass cytometry. About 50% of patients showed naive B cell repopulation after 6 months mainly with a transitional phenotype, whereas CD27+ memory B cells only rarely repopulated. This repopulation was associated with a reduction of memory T cells and activated myeloid cells, as well as reduced expression of activation/migration markers in both cell types. A plasma proteomics analysis identified proteins including TNFRSF13C, associated with B cell depletion and repopulation. Plasma levels of neurofilament light-chain protein declined after ocrelizumab treatment was not linked with B cell repopulation. These findings identify potential soluble markers for monitoring of ocrelizumab treatment in MS.

Multiple sclerosis severity variant in DYSF-ZNF638 locus associates with neuronal loss and inflammation

The genetic variant rs10191329AA has been identified to associate with faster disability accrual in multiple sclerosis (MS). We investigated the impact of rs10191329AA carriership on MS pathology and flanking genes dysferlin (DYSF) and zinc finger protein 638 (ZNF638) in the Netherlands Brain Bank cohort (n = 290) by comparing rs10191329AA (n = 6) to matched rs10191329CC carriers (n = 12). rs10191329AA carriership associated with more acute axonal stress, reduced layer 2 neuronal density, and a higher proportion of lesions with foamy microglia. In rs10191329AA donors, normal appearing white matter was characterized by a higher proportion of ZNF638+ oligodendrocytes, and normal appearing gray matter showed more DYSF+ cells. Nuclear RNA sequencing showed an upregulation of mitochondrial genes in rs10191329AA carriers. These data suggest that MS severity associates with an increased susceptibility to neurodegeneration and chronic inflammation. Understanding the role of DYSF, ZNF638, and mitochondrial pathways may reveal new therapeutic targets to attenuate MS progression.

Glymphatics and meningeal lymphatics unlock the brain-immune code

The central nervous system (CNS) was once perceived as entirely shielded from the immune system, protected behind the blood-brain barrier and thought to lack lymphatic drainage. However, recent evidence has challenged many dogmas in neuroimmunology. Indeed, by means of glymphatics, brain-derived "waste" from deep within the CNS mobilizes toward immunologically active brain borders, where meningeal lymphatic vessels are appropriately positioned to drain antigens from the brain to the periphery. Accordingly, the presentation of brain-derived self-peptides emerges at the brain's borders and drives T cell responses with suppressive properties, critical in allowing active immunosurveillance while limiting aberrant immune reactivity. Taking into consideration these concepts, we further discuss how inflammation, aging, and neurodegenerative diseases potentially reshape the repertoire of self-antigens and immune cells, disrupting the healthy dialogue between the CNS and immune system. Collectively, this evolving perspective unveils new therapeutic avenues for CNS pathologies.

Acute infectious mononucleosis generates persistent, functional EBNA-1 antibodies with high cross-reactivity to alpha-crystalline beta

We investigate the magnitude, specificity, and functional properties of Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA-1)-specific antibodies in young adults over the course of primary infection. EBNA-1-specific binding antibodies, as well as antibodies capable of antibody-dependent cellular phagocytosis (ADCP) and antibody-dependent complement deposition (ADCD), are detected. These antibodies primarily target a region of EBNA-1 known to elicit cross-reactive antibodies to several self-peptides. Higher EBNA-1 binding and ADCD antibodies are observed in individuals with at least one HLA-DRB1∗15:01 allele. Alpha-crystallin beta (CRYAB) binding and complement-fixing antibodies are detected at 6 months and 1 year following infectious mononucleosis, and CRYAB antibodies are resistant to denaturation, consistent with an affinity-matured response. Blocking experiments show that CRYAB antibodies are cross-reactive with EBNA-1. Altogether, high levels of functional EBNA-1 antibodies are generated in primary EBV infection, some of which are cross-reactive with CRYAB. Further investigation is warranted to determine whether these responses contribute to autoimmunity.

Virus-specific antibody responses in multiple sclerosis patients treated with Ocrevus

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system. B cell-depleting therapy is highly efficient in treating patients with relapsing-remitting MS (RRMS), although the mechanisms behind reducing disease progression with this type of therapy is unknown. Virus infections are associated with the onset of MS and antibodies to these have previously been suggested to supplement MS diagnostics. Based on this, we aimed to investigate the effect of Ocrevus (OCR) (B cell depletion therapy) on selected virus antibody levels. Blood samples were collected from RRMS patients before (n = 13) and during OCR treatment (n = 29) and from healthy controls (HCs) (n = 15). Serum antibodies to virus antigens from Epstein-Barr virus (EBV), severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), Rubella virus, Measles virus, John Cunningham polyomavirus, Mumps virus, Merkel cell polyomavirus, Varicella zoster virus, Influenza A virus, Human herpes virus 6, and Cytomegalovirus were analyzed by enzyme-linked immunosorbent assay. EBV nuclear antigen 1 (EBNA1) IgG levels were elevated in RRMS patients compared to HCs independent of OCR treatment. However, no significant difference in virus antibody levels was observed following OCR treatment. Only SARS-CoV-2 spike protein IgG levels were significantly reduced following OCR treatment. The effect of OCR treatment on antibody levels may correlate with the time of infection. Only EBV EBNA1 IgG levels were significantly elevated RRMS patients at baseline compared to HCs, supporting that EBV infection is involved in the development of MS and confirming the diagnostic value of EBNA1 IgG.

A probiotic approach identifies a Treg-centred immunoregulation via modulation of gut microbiota metabolites in people with multiple sclerosis and healthy individuals

BACKGROUND

Modulation of the gut microbiota composition has been suggested as a potential disease modifying therapy in immune-mediated diseases such as multiple sclerosis (MS). However, a conclusive mechanism linking gut microbiota modulation to peripheral immune responses has remained elusive so far.

METHODS

In this exploratory cohort study, people with MS (pwMS) and healthy controls (HC) supplemented a lactobacilli-rich probiotic for two or six weeks and were additionally investigated six weeks after the last intake. Immune cell phenotyping was performed in blood samples, complemented by mRNA expression analysis, serum cytokine measurements, and Treg suppression assays. Besides gut microbiota composition analysis, metabolite production was investigated in stool and serum. Links between metabolites and peripheral immune system were investigated in in vitro T cell differentiation assays.

FINDINGS

In peripheral blood, Treg cells increased in both groups, while Th1 cells were significantly reduced in pwMS. This promotion of a regulatory immunophenotype was complemented by increased concentrations of IL-10 in serum and higher expression of IL10 and CTLA4. Functional assays revealed an enhanced suppressive capacity of Treg cells due to the probiotic intervention. The tryptophan metabolite indole-3-acetate (IAA) increased in stool and serum samples of pwMS during the probiotic intake. In vitro, IAA specifically enhanced the formation of IL-10 secreting T cells together with CYP1a1 expression. This effect was blocked by addition of an aryl hydrocarbon receptor (AHR) inhibitor.

INTERPRETATION

A lactobacilli-enriched probiotic promotes a regulatory immunophenotype in pwMS, probably by enhancing AHR agonists in the gut. It may be of interest as add-on therapy in immune-mediated diseases such as MS.

FUNDING

This study has in part been funded by Novartis Pharma GmbH and BMBF grant no. 01EJ2202B.

A Chimeric Virus-Like Particle Vaccine Presenting an Immunodominant Epitope of gB Elicited Potent Neutralizing Antibodies against EBV Infection In Vitro and In Vivo

Epstein-Barr Virus (EBV) as the first characterized tumorigenic virus in humans causes heavy disease burdens. An effective vaccine is urgently needed to block EBV infection. Glycoprotein B (gB) is the essential fusogen for EBV infection of all susceptible cell types. We previously demonstrated that neutralizing antibody 3A3 targeting gB effectively blocked EBV infection in a humanized mouse model, indicating that the epitope recognized by 3A3 is the potential immunogen candidate. Hence, we rationally designed a chimeric virus-like particle (cVLP) vaccine based on the hepatitis B core antigen (HBc149) to display gB peptide, αB, recognized by 3A3 (149-αB cVLP). The engineered 149-αB cVLP vaccine self-assembled into spherical particles presenting multiple copies of αB peptide. The 149-αB cVLP vaccine induced much higher antibody titers against αB peptides than gB protein immunization. Importantly, sera antibodies elicited by the 149-αB cVLP vaccine more efficiently blocked EBV infection and membrane fusion of epithelial cells and B cells. Sera from 149-αB cVLP vaccine-immunized rabbits conferred 100% protection against EBV infection in a humanized mouse model. We demonstrated that the 149-αB cVLP vaccine induced potent antigen-specific protective immune responses and shed light on the research of peptide-based vaccines against EBV infection.

NDP52 and its emerging role in pathogenesis

Autophagy is a pro-survival process that regulates the degradation and renewal of cellular components, making it a crucial mechanism for cellular homeostasis. There are selective forms of autophagy that are specific to a number of substrates, such as pathogens (bacteria or viruses), protein aggregates or excess/damaged organelles. These processes involve as key players autophagy receptors, that link the cargo to be degraded to the autophagic machinery. Among them, NDP52 (also known as CALCOCO2) has been described to act as a "bridge" between the autophagy machinery and (1) damaged mitochondria in the mitophagy process; (2) pathogens during xenophagy or (3) proteins in the process of aggrephagy. The aim of this review is to summarize the major functions of NDP52, and to highlight the existence of two human NDP52 variants that have been described as risk or protective factors for Crohn's disease or Multiple Sclerosis and Alzheimer's disease patients, respectively. As these three diseases share common pathological features that lead to inflammation, such as mitochondria or gut microbiota dysfunctions, but also pathogenic infections, it seems clear that NDP52 could be a key player at the crossroad by acting indirectly on inflammation, and therefore a potential target for clinical applications and benefits.

Update in clinical science: Autoimmune hepatitis

Autoimmune hepatitis (AIH) is an enigmatic, relatively rare disease with a variable spectrum of presentation whose pathogenesis, diagnosis and management remain a major challenge. We have performed a review of recent developments in basic science, epidemiology, clinical science, therapeutics, and regulatory science, evaluating the challenges associated with the application of translational research and clinical trial design to a condition that is a chameleon in nature, where outcomes range from relatively benign disease through cirrhosis and acute liver failure. This review is focused on developments from 2020 onwards so we can present a forward-looking view on the challenges and remaining questions that must be addressed to improve patient care and outcomes in AIH. We also outline areas of debate and offer insights into these areas.

Epidemiology and Clinical Features of Epstein-Barr Virus and Cytomegalovirus Infections in Japanese Infants and Young Children

The recent clinical features of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections in young children in developed countries remain unclear. This study investigated the clinical features of EBV and CMV infections and the latest seroepidemiology in Japan. Seroprevalence was analyzed 303 stored serum samples using commercial Enzyme Immunosorbent Assay kits, and viral infections were investigated in a cohort of febrile children under 5 years of age. After maternal antibody levels declined, the seroprevalences of EBV and CMV gradually increased by adolescence to 42.9% and 57.1%, respectively. Among 2,732 febrile children, serum EBV and CMV DNAs were detected in 1.76% and 1.24%, respectively. Of 25 primary EBV-infected patients, 15 (60.0%) had infectious mononucleosis (IM) with significantly higher IM frequency, WBC, atypical lymphocyte ratios, AST, ALT, LDH, and EBV DNA load compared to EBV-reactivated patients. No CMV DNA-positive patients had IM. Among primary EBV-infected patients, those with IM were older and had more atypical lymphocytes and higher EBV DNA load than those without IM. The age of primary EBV infection appears to have decreased compared to reports from Western countries in the 1990s. Even among children under 5 years of age, 60.0% of those with primary EBV infection developed IM.

Disease Aggravation With Age in an Experimental Model of Multiple Sclerosis: Role of Immunosenescence

The onset of multiple sclerosis (MS) in older individuals correlates with a higher risk of developing primary progressive MS, faster progression to secondary progressive MS, and increased disability accumulation. This phenomenon can be related to age-related changes in the immune system: with age, the immune system undergoes a process called immunosenescence, characterized by a decline in the function of both the innate and adaptive immune responses. This decline can lead to a decreased ability to control inflammation and repair damaged tissue. Additionally, older individuals often experience a shift toward a more pro-inflammatory state, known as inflammaging, which can exacerbate the progression of neurodegenerative diseases like MS. Therefore, age-related alterations in the immune system could be responsible for the difference in the phenotype of MS observed in older and younger patients. In this study, we investigated the effects of age on the immunopathogenesis of experimental autoimmune encephalomyelitis (EAE). Our findings indicate that EAE is more severe in aged mice due to a more inflammatory and neurodegenerative environment in the central nervous system. Age-related changes predominantly affect adaptive immunity, characterized by altered T cell ratios, a pro-inflammatory Th1 response, increased regulatory T cells, exhaustion of T cells, altered B cell antigen presentation, and reduced NK cell maturation and cytotoxicity. Transcriptomic analysis reveals that fewer pathways and transcription factors are activated with age in EAE. These findings allow us to identify potential therapeutic targets specific to elderly MS patients and work on their development in the future.

Environmental risk factors of late-onset multiple sclerosis: A population-based case-control study

INTRODUCTION

Late-onset multiple sclerosis (LOMS) was increasingly reported over the past two decades. Understanding the risk factors associated with LOMS can help improve early diagnosis, prevention strategies, and patients' quality of life. This study aimed to assess various environmental risk factors in the patients with late-onset disease.

METHODS

This study utilized a population-based case-control study design. Primary data on verified LOMS cases were received from Iran's national MS registry, with additional information gained via telephone interviews. The potential risk factors for LOMS were examined using a questionnaire modified from global case-control studies. Age and sex-matched healthy controls were selected using face-to-face interviews. The collected data were analyzed using matched logistic regression in Stata software version 14, reporting adjusted odds ratios (OR), and 95 % confidence intervals, with a significance level set at p < 0.05.

RESULTS

This study examined 82 LOMS cases and 207 matched controls. The mean age of cases and controls was 61 years. The findings revealed that moderate and high sunlight exposure during adolescence were related with 0.33 (95 % CI: 0.18-0.58) and 0.15 (95 % CI: 0.04-0.46) times decreased risks of developing LOMS, respectively. Similarly, compared to those with low sunlight exposure, participants with high and moderate sunlight exposure during adulthood had a lower chance of developing MS disease (OR = 0.35, 95 % CI: 0.18-0.69) and (OR = 0.40 95 % CI: 0.18-0.85) receptively. Moreover, age at first menstruation (p = 0.45), age at first delivery (p = 0.49), abortion history (p = 0.79), and oral contraceptive consumption (p = 0.18) did not significantly differ among the groups (all p > 0.05). The odds of developing LOMS were 2.47 (95 % CI: 1.05-5.81) times higher for 10 to 90 min of heavy physical activity per week and 2.39 (95 % CI: 1.08-5.27) times higher for over 90 min. Various emotional stress, including death of a loved one (OR = 2.19, 95 % CI: 1.07-4.48), family disruption (OR = 2.93 95 % CI: 1.62-1.02), homelessness (OR = 9.1 95 % CI: 1.4-57.5), employment dismissal (OR = 4.0, 95 % CI: 1.31-12.1), and unemployment (OR = 3.1, 95 % CI: 1.25-7.62), were significantly associated with an increased risk of developing LOMS. Depression (OR = 5.5, 95 % CI: 2.7-10.9), measles (OR = 2.63, 95 % CI: 1.4-4.8), and a family history of MS (OR = 4.7, 95 % CI: 1.4-15.6) were also associated with higher risk of LOMS development.

CONCLUSION

Sunlight exposure was shown to have a strong protective impact against LOMS. Furthermore, intensive physical activity, psychological stresses such as family upheavals, medical illnesses such as depression, and a positive family history of MS may all be associated with an increased risk of LOMS. These findings emphasized the importance of preventive measures for older individuals affected by the disease.

Multiple sclerosis: an immune attack on astrocyte-mediated ion and water homeostasis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS. The chain of events that results in demyelinating lesions is not understood, although most theories assume a primary immune attack on myelin. However, the glial cell adhesion molecule GlialCAM, which forms part of a protein complex in astrocytic endfeet that is crucial for brain ion and water homeostasis, was recently identified as a target for autoimmunity in patients with MS. This complex also includes the astrocytic transmembrane protein MLC1, the water channel aquaporin 4 (AQP4) and the potassium channel KIR4.1. Autoimmunity against AQP4 underlies another demyelinating disorder, neuromyelitis optica, and autoimmunity against KIR4.1 has been implicated in a subtype of MS. Genetic defects in any of these proteins cause leukodystrophies with disruption of brain ion and water homeostasis, which is regulated by astrocytes and secondarily affects myelin. In this Perspective, we argue that an immune attack on the ion and water homeostasis machinery in astrocytic endfeet, rather than directly on myelin, is the primary event in MS and that myelin damage is a consequence of astrocyte dysfunction. This hypothesis is supported by pathological studies on tissue from people with MS and has important implications for disease models and therapy targets.

Paediatric autoimmune uveitis is associated with intraocular antibodies against Epstein-Barr virus Nuclear Antigen 1 (EBNA-1)

BACKGROUND

Non-infectious uveitis is an immune-mediated disease characterized by vision-threatening inflammation within the eye. Increasing evidence indicates that microbial agents promote non-infectious uveitis, but the natural history of immune responses to pathogens in patients remains unexplored. We determined intraocular antibodies against pathogens in paediatric uveitis.

METHODS

We used peptide microarrays containing 3760 linear B-cell epitopes from 196 human pathogens to profile IgG levels in eye fluid biopsies and paired serum samples from 18 Dutch paediatric patients and 6 age-matched controls. We compared intensities of single epitopes and clusters based on overlapping amino acid sequence of peptides. Next-generation sequencing data was obtained to determine the HLA-DRB1∗15:01 genotype.

FINDINGS

Intraocular antibody profiles largely matched serum profiles and were characterized by high IgG against the conserved PALTAVET-motif of enterovirus family members, as well as broad epitope reactivity against Epstein-Barr virus (EBV). The aqueous humour of patients showed elevated levels of antibodies against peptides containing the RRPFFHPV-motif of Epstein-Barr Virus Nuclear Antigen 1 [EBNA-1]. Antibody levels against the RRPFFHPV-motif of EBNA1 were significantly higher in individuals that carry the HLA-DRB1∗15:01 risk allele of paediatric uveitis.

INTERPRETATION

Intraocular antibodies against an immunogenic epitope of EBV showed an association with paediatric uveitis, particularly HLA-DRB1∗15:01 positive uveitis, indicating a potential link between EBV-specific immune responses and autoimmune uveitis.

FUNDING

Funding for this research was received from Fischer Stichting (UZ2022-3), ODAS (2021-02), LSBS and ANVVB.

STAT3, MYC, and EBNA1 cooperate through a ZC3H18 transcriptional network to regulate survival and proliferation of EBV-positive lymphomas

Epstein-Barr virus (EBV), a common gamma-herpesvirus linked to various malignancies, exploits host cellular mechanisms to promote oncogenesis. Our previous research identified the zinc finger protein ZC3H18 as a novel component of the cellular DNA replication machinery in the context of EBV-driven tumorigenesis. We now demonstrate that ZC3H18 expression is upregulated in EBV-transformed and cancer cell lines, as well as in EBV-positive diffuse large B-cell lymphomas from AIDS patients, compared to their EBV-negative counterparts, supporting its activation by EBV. Our experiments show that ZC3H18 expression is regulated by the key oncogenic factors STAT3 and MYC, as well as the essential viral protein EBNA1. Using inhibitors and genetic knockdown, we find that suppressing STAT3, MYC, or EBNA1 leads to decreased ZC3H18 levels, reduced cell viability, and increased apoptosis in EBV-positive B lymphoma cells. Furthermore, ZC3H18, STAT3, MYC, and EBNA1 mutually support each other's expression through a complex transcriptional network. Notably also, ZC3H18 transcriptionally enhances components of the NF-κB pathway, contributing to NF-κB signaling even in the absence of the EBV oncoprotein LMP1, which is crucial for cell proliferation and survival of several EBV-associated malignancies. Our findings reveal a novel regulatory axis in EBV-positive cancer cells involving STAT3, MYC, EBNA1, & ZC3H18, also linking ZC3H18 to the NF-κB pathway independently of LMP1. The involvement of EBNA1 in this network may explain, at least in part, the preferential upregulation of ZC3H18 in EBV-associated tumors and highlights predictive and therapeutic possibilities for such cancers.

A unifying model for multiple sclerosis

Multiple sclerosis (MS) is a complex neurodegenerative disorder with unresolved cause that has been the subject of intensive research. A variety of putative models have been proposed to explain the course of disease. The preeminent mechanisms are suggested to be based on autoimmunity, including via viral epitope mimicry, although difficulties with a classical autoimmunity model for MS have been described. One prior idea that incorporates consideration of viral-self-cross-reactivity is that reactivated HHV-6A virus might induce subsequent reactivation of another virus, EBV, in a relay, resulting in a cascade of downstream consequences. Here, an alternative model for MS is proposed. This posits a viral reactivation relay in which EBV reactivation in the brain precedes HHV-6A reactivation in oligodendrocytes and neurons. At this juncture, relapsing-remitting MS (RRMS) can ensue to generate characteristic lesions, dominated by outbreaks of viral reactivation and CD8+T-cell-mediated cytotoxicity and inflammation. Additionally, self-targeting antibodies can be raised to mark the onset of progressive MS in a subset of patients. This model harmonises a plethora of prior evidence from diverse fields. It is suggested that future studies should challenge this new model for MS and that it provides direction for future approaches to prevention and therapy.

Adipokines in multiple sclerosis: Immune dysregulation, neuroinflammation, and therapeutic opportunities

Multiple sclerosis (MS) is a chronic autoimmune disorder of the central nervous system (CNS), characterized by demyelination, neuroinflammation, and the progressive accumulation of neurologic deficits. Adipose tissue secretes predominantly the bioactive molecules, known as adipokines, which have drawn considerable attention for their roles in modulating immune and metabolic pathways in people with MS (PwMS). Dysregulated adipokines, such as resistin, leptin, and chemerin, induce pro-inflammatory T-cell polarization while deteriorating Blood-Brain Barrier (BBB) integrity. Adiponectin, by contrast, has both immunomodulatory and neuroprotective functions. The opposing functionality highlights the biomarker and the therapeutic potential of adipokines. Preclinical and translational findings have shed light on the role of adipokines in the pathophysiology of MS by influencing T-cell, glial, and BBB functions. In clinical settings, the assessment of adipokines can function as an indicator of prognosis and diagnosis via distinct patterns of expression. In addition, alterations to adipokine profiles through lifestyle changes and pharmaceutical treatment may complement established disease-modifying treatments (DMTs). This study has highlighted the multifaceted role of adipokines in MS management, while further studies exploring the role of adipokine-mediated immunometabolic regulation are suggested.

Irisin restrains neuroinflammation in mouse experimental autoimmune encephalomyelitis via regulating microglia activation

Introduction

Multiple sclerosis is a chronic autoimmune demyelinating disorder predominantly affecting the white matter of the central nervous system, with experimental autoimmune encephalomyelitis (EAE) serving as its classical animal model. Irisin, a glycosylated protein derived from the proteolytic cleavage of fibronectin type III domain-containing protein 5, plays a significant role in metabolic regulation and inflammatory modulation within the organism.

Methods

In this study, we systematically investigated the therapeutic effects and underlying mechanism of Irisin on EAE and BV2 microglial cells through comprehensive methodologies including quantitative real-time polymerase chain reaction, immunofluorescence staining and western blot.

Results

Irisin exerts neuroprotective effects in EAE mice, significantly ameliorating both clinical and pathological manifestations of the disease. Mechanistically, Irisin attenuated inflammatory response and reduced the number of microglia through NF-κBp65 signaling pathway.

Conclusion

In conclusion, these results collectively suggest that Irisin alleviates EAE progression by suppressing microglia activation via the NF-κBp65 pathway, highlighting its potential as a promising therapeutic target for multiple sclerosis treatment.

Epstein-Barr virus pathogenesis and emerging control strategies

Sixty years after its discovery as the first human tumour virus, Epstein-Barr virus (EBV)-specific therapies and vaccines have entered clinical trials. These might not only be applicable for EBV-associated malignancies, where the virus was originally discovered, but also to immunopathologies, including the autoimmune disease multiple sclerosis, which might be triggered in susceptible individuals by primary EBV infection. This Review discusses the surprisingly large spectrum of diseases that EBV seems to cause, as well as which of these might be treated by the therapeutic approaches that are currently being developed or are already clinically applied. New pharmacological inhibitors, antibody therapies, adoptive T cell therapies and active vaccinations are beginning to offer possibilities to target the various EBV infection programmes that are associated with different diseases. These novel developments might allow us to specifically target EBV rather than its host cells in virus-associated pathologies.

Multiple sclerosis: what have we learned and can we still learn from electron microscopy

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease marked by the formation of demyelinated lesions in the central nervous system. MS lesions can undergo remyelination, temporarily alleviating symptoms, but as the disease advances, remyelination becomes less effective. Beyond lesions, normal-appearing brain tissue exhibits subtle alterations, potentially indicating a broader, diffuse pathology and/or increased susceptibility to lesion formation. The pathology of MS varies between grey and white matter lesions and their normal-appearing regions, which most likely relates to their distinct cellular composition. Despite insights gained from MRI studies, serum and blood analyses, and post-mortem tissue examination, the molecular mechanisms driving MS lesion formation and persistent demyelination remain poorly understood. Exploring less conventional methods, such as electron microscopy (EM), may provide valuable new insights. EM offers detailed, nanometre-scale structural analysis that may enhance findings from immunohistochemistry and 'omics' approaches on MS brain tissue. Although earlier EM studies from before the 1990's provided some foundational data, advancements in EM technology now enable more comprehensive and detailed structural analysis. In this review we outline the pathogenesis of MS, summarize current knowledge of its ultrastructural features, and highlight how cutting-edge EM techniques could uncover new insights into pathological processes, including lesion formation, remyelination failure and diffuse pathology, which may aid therapeutic development.

CMV serostatus is associated with improved survival and delayed toxicity onset following anti-PD-1 checkpoint blockade

Cytomegalovirus (CMV) is a globally endemic latent herpes virus that profoundly impacts T cell immunity. We investigated the oncological consequences of CMV infection across 341 prospectively recruited patients receiving immune checkpoint blockade (ICB) for melanoma. CMV+ patients with metastatic melanoma (MM) have higher lymphocyte counts, reduced neutrophil to lymphocyte ratio and divergent CD8+ T cell gene expression. Combination anti-CTLA-4/anti-PD-1 ICB, but not single-agent anti-PD-1 ICB, induces cytotoxicity and CMV-associated gene expression in CD8+ T cells from CMV- patients. Correspondingly, overall survival was independent of CMV serostatus in combination anti-CTLA-4/anti-PD-1 ICB recipients (CMV+ hazard ratio for death: 1.02, P = 0.92), whereas CMV+ single-agent anti-PD-1 ICB recipients had improved overall survival (CMV+ hazard ratio for death: 0.37, P < 0.01), a finding also seen in CMV+ adjuvant single-agent anti-PD-1 ICB recipients (CMV+ hazard ratio for recurrence: 0.19, P = 0.03). We identify TBX21, encoding T-bet, as a transcriptional driver of CMV-associated CD8+ T cell gene expression, finding that TBX21 expression is predictive of overall survival (hazard ratio: 0.62, P = 0.026). CMV+ patients unexpectedly show reduced cumulative incidence of grade 3+ immune-related adverse events at 6 months (0.30 versus 0.52, P = 2.2 × 10-5), with lower incidence of colitis (P = 7.8 × 10-4) and pneumonitis (P = 0.028), an effect replicated in non-melanoma ICB recipients (n = 58, P = 0.044). Finally, we find reduced CMV seropositivity rates in patients with MM compared with UK Biobank controls (odds ratio: 0.52, P = 1.8 × 10-4), indicating CMV seropositivity may protect against MM. Specifically, patients with BRAF-mutated MM are less likely to be CMV+ (odds ratio = 2.2, P = 0.0054), while CMV- patients present 9 yr earlier with BRAF wild-type MM (P = 1.3 × 10-4). This work reveals an interaction between CMV infection, MM development according to BRAF status and response to ICB, while demonstrating CMV infection is protective against severe ICB immune-related adverse events, highlighting the potential importance of previous infection history and chronic immune activation in MM development and immunotherapy outcomes.

Population preventable fraction of total multiple sclerosis risk associated with non-specific effects of vaccinations against hepatitis B virus and influenza A and B viruses in a middle eastern country

BACKGROUND

This study aimed to quantify the population attributable (or prevented) fraction (PAR or PPF) of common risk factors for multiple sclerosis (MS) including family history of MS and vaccine uptake against influenza A and B viruses and hepatitis B virus.

METHODS

Confirmed MS cases and MS-free controls pair-matched on age (± 5 years), sex and nativity with cases were enrolled. Data were collected through face-to-face interviews both from the cases and controls. An unconditional multivariable logistic regression model was used to analyze the data by including matching factors i.e., age, sex, and nativity as confounders and MS family history and vaccine uptake against influenza viruses and hepatitis B virus as exposures. The adjusted odds ratios and their 95% confidence intervals (CI) were used to compute PAR for family history of MS and PPFs for vaccine uptake against HBV and influenza virus along with their respective 95% CIs.

RESULTS

A total of 110 MS cases, and their 110 pair-matched controls were enrolled. The PAF for family history of MS revealed that 22% of MS risk in the population is contributed by family history of MS (PAF = 0.22; 95% CI: 0.10-0.32). The PPFs for vaccination uptake against influenza viruses and/or hepatitis B virus were associated with a significant nonspecific protection against MS risk by 20% (PPF = 0.20; 95% CI: 0.004-0.43) or 30% (PPF = 0.30; 95% CI: 0.03-0.65) respectively. Moreover, the computed joint PPF for vaccination uptake against influenza viruses and hepatitis B virus showed a significantly increased 44% non-specific protection against MS risk (PPF = 0.44; 95% CI: 0.03-0.80).

CONCLUSIONS

Familial history of MS is associated with 22% population attributable fraction for MS risk, whereas vaccine uptake against influenza viruses or hepatitis B virus conferred a nonspecific protection with population prevented fractions of 20% and 30% respectively suggesting a substantial potential for public health interventions to minimize MS risk in this and other similar settings.

Detection of viral sequences at single-cell resolution identifies novel viruses associated with host gene expression changes

The increasing use of high-throughput sequencing methods in research, agriculture and healthcare provides an opportunity for the cost-effective surveillance of viral diversity and investigation of virus-disease correlation. However, existing methods for identifying viruses in sequencing data rely on and are limited to reference genomes or cannot retain single-cell resolution through cell barcode tracking. We introduce a method that accurately and rapidly detects viral sequences in bulk and single-cell transcriptomics data based on the highly conserved RdRP protein, enabling the detection of over 100,000 RNA virus species. The analysis of viral presence and host gene expression in parallel at single-cell resolution allows for the characterization of host viromes and the identification of viral tropism and host responses. We apply our method to peripheral blood mononuclear cell data from rhesus macaques with Ebola virus disease and describe previously unknown putative viruses. Moreover, we are able to accurately predict viral presence in individual cells based on macaque gene expression.

Human Endogenous Retroviruses as Novel Therapeutic Targets in Neurodegenerative Disorders

Human Endogenous Retroviruses comprise approximately 8% of the human genome, serving as fragments of ancient retroviral infections. Although they are generally maintained in a silenced state by robust epigenetic mechanisms, specific HERV groups, particularly HERV-W and HERV-K, can become derepressed under specific pathological conditions, thereby contributing to the initiation and progression of neuroinflammatory and neurodegenerative processes. Preclinical studies and clinical trials, such as those investigating monoclonal antibodies, indicate that directly targeting these elements may offer a novel therapeutic strategy. In this review, we provide an overview of HERVs' biology, examine their role in neurodegenerative diseases such as amyotrophic lateral sclerosis, multiple sclerosis, Alzheimer's disease, and Parkinson's disease, and explore their therapeutic prospects, highlighting both the challenges and the potential future research directions needed to translate these approaches into clinical interventions.

Environmental and Familial Risk Factors for Multiple Sclerosis: Insights from a Saudi Arabian Cohort

Background and Objectives: Multiple sclerosis (MS) is a chronic autoimmune condition that impacts the central nervous system and has a rising incidence globally, especially in Saudi Arabia. Materials and Methods: This study examines environmental, lifestyle, and familial risk factors associated with MS in the Aljouf Region by a cross-sectional analysis of 155 clinically diagnosed MS patients. Data were gathered using structured questionnaires and medical record examinations to evaluate sociodemographic characteristics, sun exposure, smoking, obesity, eating habits, and childhood infections. Results: Logistic regression research found insufficient daily sun exposure (<15 min/day), smoking, obesity, and childhood measles infection as significant risk factors, but substantial weekend sun exposure (>4 h/day), exclusive breastfeeding, and regular fish consumption were deemed protective. While familial history of MS was statistically significant (5.5%, p = 0.04), parental consanguinity (38.7%) did not show a significant association with MS risk (p = 0.07). Conclusions: The findings underscore the complex nature of MS and the pressing necessity for preventive efforts, such as advocating for vitamin D supplementation, smoking cessation, obesity prevention, and dietary adjustments. Mitigating these controllable risk factors may alleviate the prevalence of MS in Saudi Arabia.

Clinical Features and Laboratory Findings of Hospitalized Children with Infectious Mononucleosis Caused by Epstein-Barr Virus from Croatia

The aim of this retrospective 6-year study was to analyze demographic, laboratory and clinical features of 212 patients (<18 years of age) with EBV-associated infectious mononucleosis (IM) hospitalized in a tertiary clinical care center in southeastern Europe and to identify possible predictors of complications. The median patient age was 14.7 years (IQR 7.7-16.5 years), with 59.4% of patients aged between 13 and 18 years. A total of 51.2% of patients were hospitalized within 7 days following the onset of symptoms (median duration of hospitalization was 9 days, IQR 7-11 days). The most common symptoms included fever (97.16%), tonsillitis (87.3%), lymphadenopathy (79.2%), hepatomegaly (77.4%) and splenomegaly (73.1%). Symptom distribution, maximal fever and fever duration did not differ among different age groups. The most common complications included tonsillar hypertrophy, thrombocytopenia, anemia, neutropenia and leukopenia but all patients showed favorable outcomes. Patients who developed three or more complications and those presenting with thrombocytopenia showed significantly longer hospitalization durations. Platelet count, bilirubin, ESR and AST were identified as the most accurate predictors of hospitalization duration using multiple linear regression analysis. Therefore, our results suggest that clinical assessment of individual patients remains the most reliable parameter for patient management and that laboratory findings play only a supporting role.

A disease-specific convergence of host and Epstein-Barr virus genetics in multiple sclerosis

Recent sero-epidemiological studies have strengthened the hypothesis that Epstein-Barr virus (EBV) may be a causal factor in multiple sclerosis (MS). Given the complexity of the EBV-host interaction, various mechanisms may be responsible for the disease pathogenesis. Furthermore, it remains unclear whether this is a disease-specific process. Here, we showed that genes encoding EBV interactors are enriched in loci associated with MS but not with other diseases and in prioritized therapeutic targets. Analyses of MS blood and brain transcriptomes confirmed a dysregulation of MS-associated EBV interactors affecting the CD40 pathway. Such interactors were strongly enriched in binding sites for the EBV nuclear antigen 2 (EBNA2) viral transcriptional regulator, often in colocalization with CCCTC binding factor (CTCF) and RNA Polymerase II Subunit A (POLR2A). EBNA2 was expressed in the MS brain. The 1.2 EBNA2 allele downregulated the expression of the CD40 MS-associated gene analogously to the CD40 MS-risk variant. Finally, we showed that the 1.2 EBNA2 allele associates with the risk of MS. This study delineates how host and viral genetic variability converge in MS-specific pathogenetic mechanisms.

Emerging drugs for Epstein-Barr virus associated-diseases

Epstein-Barr virus (EBV) is the first identified oncogenic virus. It causes three types of diseases: lymphomas, carcinomas, and autoimmune diseases. It is estimated that two hundred thousand deaths are due to EBV each year. After a primary infection, EBV can remain latent lifelong. Reactivation to lytic phase can be induced by various drugs including small organic molecules, biologics, or a combination of both. In this review, we identified the most relevant results obtained with small organic compounds against Epstein-Barr virus-associated diseases. Specific treatments targeting Epstein-Barr Nuclear Antigen 1 are emerging concerning small organic molecules and showed promising results against several EBV-related malignancies.

Exploring the role of EBV in multiple sclerosis pathogenesis through EBV interactome

Background

Epstein-Barr virus (EBV) is a known risk factor for multiple sclerosis (MS), even though the underlying molecular mechanisms are unclear and engage multiple immune pathways. Furthermore, the ultimate role of EBV in MS pathogenesis is still elusive. In contrast, Cytomegalovirus (CMV) has been identified as a protective factor for MS.

Objectives

This study aims to identify MS-associated genes that overlap with EBV interactome and to examine their expression in immune and glial cell subtypes.

Methods

We used P-HIPSTer, GWAS, and the Human Protein Atlas (HPA) to derive data on the EBV interactome, MS-associated genes and single-cell gene expression in immune and glial cells. The geneOverlap and dplyr R packages identified overlapping genes. A similar analysis was done for CMV and Adenovirus as negative control. Metascape and GTEx analyzed biological pathways and brain-level gene expression; transcriptomic analysis was performed on glial cells and peripheral blood in MS and controls. All the analyses performed in this study were generated using publicly available data sets.

Results

We identified a "core" group of 21 genes shared across EBV interactome, MS genes, and immune and glial cells (p<0.001). Pathway analysis revealed expected associations, such as immune system activation, and unforeseen results, like the prolactin signaling pathway. BCL2 in astrocytes, MINK1 in microglia were significantly upregulated while AHI1 was downregulated in MS compared to controls.

Conclusions

Our findings offer novel insights into EBV and CMV interaction with immune and glial cells in MS, that may shed light on mechanisms involved in disease pathophysiology.

Encephalitis: intersections between infections and autoimmunity

BACKGROUND

Encephalitis is a serious condition accompanied by substantial morbidity. Although infections have long been recognized as causes, there has been growing appreciation of autoimmune aetiologies of encephalitis, most notably those associated with anti-neuronal antibodies.

OBJECTIVES

This narrative review focuses on points of commonality among clinical features, pathophysiology, and management of infectious and autoimmune encephalitis, while also noting important distinctions.

SOURCES

I identified studies, comprising research articles and reviews, that provide data on the epidemiology of infectious versus autoimmune encephalitis, and on clinical features that either co-occur or distinguish between them. In addition, I reviewed management practices, preclinical data, and clinical trials on the treatment of infectious and autoimmune encephalitis.

CONTENT

I first discuss the clinical overlap between infectious and autoimmune causes of encephalitis, highlighting features and syndromes that can confound the diagnosis. I next turn to the pathogenic overlap between the two, exemplified by the development of autoimmune encephalitis with antibodies against the N-methyl-D-aspartate receptor following a bout of herpes simplex encephalitis. Finally, I discuss management of infectious and autoimmune encephalitis, focusing on current and future avenues of treatment.

IMPLICATIONS

Although our understanding of causes of infectious and autoimmune encephalitis has improved considerably over the past decade, diagnosis remains challenging given the clinical and pathophysiological overlap between the two. Large multicentre clinical trials are needed to evaluate treatments that target inflammation and potentially benefit both.

Toxoplasma gondii chronic infection decreases visceral nociception through peripheral opioid receptor signaling

By eliciting immune activation in the digestive tract, intestinal pathogens may perturb gut homeostasis. Some gastrointestinal infections can indeed increase the risk of developing post-infectious irritable bowel syndrome (PI-IBS). Intriguingly, the prevalent foodborne parasite Toxoplasma gondii has not been linked to the development of PI-IBS and the impact of this infection on colon homeostasis remains ill-defined. We show in a mouse model that latent T. gondii decreases visceral nociceptive responses in an opioid signaling-dependent manner. Despite the accumulation of Th1 and cytotoxic T cells in the colon of latently infected mice, the selective invalidation of enkephalin gene in T cells ruled out the involvement of T cell-derived enkephalins in hypoalgesia. These findings provide clues about how this widespread infection durably shapes the gut immune landscape and modifies intestinal physiological parameters. They suggest that in contrast to other gut microbes, T. gondii infection could be negatively associated with abdominal pain.

Stratifying Multiple Sclerosis Susceptibility Risk: The Role of HLA-E*01 and Infectious Mononucleosis in a Population Cohort

BACKGROUND

Epstein-Barr Virus (EBV) and its clinical manifestation, infectious mononucleosis (IM), are strongly linked to MS risk. A recent in vitro study suggests that HLA-E*01:03, in contrast to HLA-E*01:01, may protect against MS through more effective immune responses against EBV-infected B cells. However, the role of HLA-E*01 in MS remains unclear.

METHODS

We investigated if HLA-E*01:01 was significantly associated with higher MS risk in individuals with a history of IM diagnosis, using 487,144 individuals from the UK Biobank's cohort. We estimated the interaction between HLA-E*01:01 and IM using Cox proportional hazard models, adjusting for demographics, smoking, childhood body size, older siblings, and MS-related HLA alleles (e.g., HLA-DRB1*15:01).

RESULTS

HLA-E*01:01 allele alone was not significantly associated with IM or MS (p > 0.05). However, a significant interaction between HLA-E*01:01 and IM history was observed in relation to MS risk (p < 0.001). Specifically, MS risk was significantly higher in both HLA-E*01:01 heterozygotes (HR = 1.74 [95% CI: 1.36, 1.97], p < 0.001) and homozygotes (HR = 3.01 [95% CI: 1.81, 3.88], p < 0.001) with IM history, compared to HLA-E*01:03 homozygotes. Conversely, these associations were non-significant in individuals without IM history (p > 0.05). The estimated proportion of the combined risk attributable to interaction effects was 40% in HLA-E*01:01 heterozygotes and 65% in HLA-E*01:01 homozygotes.

CONCLUSIONS

HLA-E*01:01 carriers diagnosed with IM are at significantly increased risk of MS, independently from other MS-related HLA alleles. This supports the hypothesis that HLA-E*01:01 may contribute to MS susceptibility due to weaker immune control over EBV infection. Incorporating HLA-E*01:01 into existing MHC-based MS risk models could then enhance personalized risk assessments in individuals with IM history.

Unveiling the Etiopathogenic Role of Epstein-Barr Virus in Periodontitis

Periodontitis, a prevalent and costly oral disease, remains incompletely understood in its etiopathogenesis. The conventional model attributes it to pathogenic bacteria, but emerging evidence suggests dysbiosis involving bacteria, herpesviruses, and an exaggerated host immune response. Among herpesviruses, Epstein-Barr virus (EBV) closely links to severe periodontitis, yet the mechanisms underlying EBV-related pathogenesis remain elusive. This study examined the presence, methylation patterns, and infection states of EBV in gingival tissues from healthy patients and those with periodontitis. It also assessed gene expression differences associated with EBV through whole-genome transcriptomic profiling in healthy and periodontitis-affected tissues. EBV DNA was found at similar frequencies in healthy and periodontitis tissues, suggesting common EBV infection even before disease manifestation. In healthy tissues, mostly unmethylated EBV genomes indicated lytic infection in gums, consistent with the literature on lytic EBV spread in epithelia and continual significant virus release in the saliva of healthy carriers. Conversely, EBV DNA in periodontitis tissues showed both methylated and unmethylated patterns, suggesting a mix of latent and lytic genomes. This indicates the coexistence of latent EBV in B-cells and lytic EBV in plasma cells (PCs), linking EBV presence with both cell types in periodontitis. Whole-genome transcriptomic analysis revealed distinct expression profiles in EBV-positive periodontitis tissues, with upregulated genes associated with inflammatory/immune responses and B-cell and PC markers, while downregulated genes were related to epithelial structure and organization. The EBV-positive periodontitis signature differed distinctly from that of EBV-positive healthy gums, eliciting only a typical viral-induced immune response. These findings provide new insights into EBV physiopathology in the gum, notably assigning a direct etiopathogenetic contribution to EBV in periodontitis. The results suggest a model where EBV can commonly, and apparently asymptomatically, spread in healthy gingiva but may also aggravate inflammation in the context of gum dysbiosis, involving infiltration of B-cells and PCs and loss of epithelial integrity.

TGFβ links EBV to multisystem inflammatory syndrome in children

In a subset of children and adolescents, SARS-CoV-2 infection induces a severe acute hyperinflammatory shock1 termed multisystem inflammatory syndrome in children (MIS-C) at four to eight weeks after infection. MIS-C is characterized by a specific T cell expansion2 and systemic hyperinflammation3. The pathogenesis of MIS-C remains largely unknown. Here we show that acute MIS-C is characterized by impaired reactivation of virus-reactive memory T cells, which depends on increased serum levels of the cytokine TGFβ resembling those that occur during severe COVID-19 (refs. 4,5). This functional impairment in T cell reactivity is accompanied by the presence of TGFβ-response signatures in T cells, B cells and monocytes along with reduced antigen-presentation capabilities of monocytes, and can be reversed by blocking TGFβ. Furthermore, T cell receptor repertoires of patients with MIS-C exhibit expansion of T cells expressing TCRVβ21.3, resembling Epstein-Barr virus (EBV)-reactive T cell clones capable of eliminating EBV-infected B cells. Additionally, serum TGFβ in patients with MIS-C can trigger EBV reactivation, which is reversible with TGFβ blockade. Clinically, the TGFβ-induced defect in T cell reactivity correlates with a higher EBV seroprevalence in patients with MIS-C compared with age-matched controls, along with the occurrence of EBV reactivation. Our findings establish a connection between SARS-CoV-2 infection and COVID-19 sequelae in children, in which impaired T cell cytotoxicity triggered by TGFβ overproduction leads to EBV reactivation and subsequent hyperinflammation.

Human Immune Responses to Epstein-Barr Virus Highlighted by Immunodeficiencies

Inborn errors of immunity (IEIs) represent unique in natura models that uncover key components of immunity in humans, in particular those that predispose to infections. Epstein-Barr virus (EBV) is one of the most common opportunistic infectious agents in humans and is responsible for several diseases, including infectious mononucleosis, nonmalignant and malignant lymphoproliferative disorders, hemophagocytic lymphohistiocytosis, and smooth muscle and epithelial tumors. For most individuals, EBV infection persists for life without pathological consequences. IEIs that do not predispose to EBV infection suggest that innate and humoral responses are not necessary or redundant for the immune response to EBV. IEIs associated with high susceptibility to EBV infection provide unequivocal genetic proof of the central role of CD8+ T cell responses in immunity to EBV. They also highlight the distinct steps and pathways required for, on the one hand, the effector cytotoxic functions of CD8+ T cells and, on the other hand, the expansion and maturation of cytotoxic CD8+ T cells.