Targeting Epstein-Barr virus infection as an intervention against multiple sclerosis

Antimicrobials use and infection hospital contacts as proxies of infection exposure at ages 0-2 years and risk of infectious mononucleosis

Infectious mononucleosis (IM) often results from late primary infection with Epstein-Barr virus (EBV). Exposure to EBV at ages 0-2 years from, e.g., siblings therefore protects against IM. Using Danish registers, we therefore followed children born in 1997 through 2015 from age 3 years for a hospital contact with an IM diagnosis as outcome with the number of antimicrobial prescriptions filled before age 3 years as a proxy of infection pressure and the main exposure in stratified Cox regressions. The main analyses used sibships as strata primarily to adjust for health-seeking behaviour with further possible adjustments for age, sex, calendar period and sibship constellation. In these analyses we followed 7087 children, exposed on average to 3.76 antimicrobials prescriptions. We observed a crude hazard ratio for IM per unit increase in cumulative antimicrobial use of 1.00 (95% confidence interval 0.99, 1.02), with similar results in adjusted analyses. The hypothesis that children with the largest use of antimicrobials at ages 0-2 years would subsequently have the lowest risk of IM within a sibship was not corroborated by the data. Furthermore, sibship-matched analyses provided no support for some common early-life immune system characteristics being predictive of IM.

Risk prediction for liver injury in Epstein-Barr virus infection in pediatric respiratory tract infections

BACKGROUND

Epstein-Barr virus (EBV) infection is likely to co-occur in pediatric respiratory tract infections (RTIs). Liver injury is the common complication of EBV infection. The detailed risk factors for liver injury in EBV infection remain elusive. We aimed to investigate the incidence, characteristics and potential risk factors for liver injury in EBV infection for early risk prediction.

METHODS

We retrospectively recruited the pediatric RTIs cases with EBV infection according to a predefined criteria from our hospital between January 2015 and December 2017. We extracted the clinical and laboratory data from the electronical medical records. The impact of age, gender, and various parameters on the liver injury risk was investigated. Univariate logistic regression analysis was performed to analyse the association between clinical/laboratory parameters and liver injury. The related indexes were enrolled in the multivariate logistic regression analysis. Decision curve analysis was used to yield the value of related parameters in predicting liver injury. Receiver operating curve (ROC) analysis was applied to produce the C-index of white blood cell (WBC) count for liver injury. We also tested the non-linear association between WBC count and alanine aminotransferase (ALT).

RESULTS

A total of 216 pediatric RTIs with EBV infection were enrolled. EBV infection is more likely to occur during the winter season. Cytomegalovirus infection was independently associated with liver injury in EBV infection (OR = 6.972, 95% CI = 1.648-29.490, p = 0.008). WBC count was independently associated with liver injury in EBV infection (OR = 1.169, 95% CI = 1.051-1.301, p = 0.004). The P interaction value between WBC count and cytomegalovirus was 0.149. The decision curve analysis showed that WBC count had larger area under curve compared with platelet (PLT) and birthweight (BW). ROC analysis yielded the c-index of WBC count: 0.75 and cut-point of 8.3. The turning point of WBC count in its association with ALT was 16.8. The p value before and after the turning point was < 0.001 and 0.123, respectively.

CONCLUSIONS

Cytomegalovirus co-infection demonstrated 5.972 more times of liver injury risk in EBV infection. WBC count was an independent biomarker for liver injury before the turning point of 16.8 in EBV infection. More attention should be paid to the risk of EBV infection in the winter. Cytomegalovirus infection and WBC count merit attention in the monitoring of possible liver injury in EBV infection among pediatric RTIs.

Advances in mRNA vaccines for viral diseases

Since the onset of the pandemic caused by severe acute respiratory syndrome coronavirus 2, messenger RNA (mRNA) vaccines have demonstrated outstanding performance. mRNA vaccines offer significant advantages over conventional vaccines in production speed and cost-effectiveness, making them an attractive option against other viral diseases. This article reviewed recent advances in viral mRNA vaccines and their delivery systems to provide references and guidance for developing mRNA vaccines for new viral diseases.

Siblings reduce multiple sclerosis risk by preventing delayed primary Epstein-Barr virus infection

Epstein-Barr virus infection, and perhaps almost exclusively delayed Epstein-Barr virus infection, seems to be a prerequisite for the development of multiple sclerosis. Siblings provide protection against infectious mononucleosis by occasionally preventing delayed primary Epstein-Barr virus infection, with its associated high risk of infectious mononucleosis. Each additional sibling provides further protection according to the age difference between the index child and the sibling. The closer the siblings are in age, the higher the protection, with younger siblings being more protective against infectious mononucleosis than older siblings. If the hypothesis that delayed Epstein-Barr virus infection is necessary for the development of multiple sclerosis is true, then the relative risk of multiple sclerosis as a function of sibship constellation should mirror the relative risk of infectious mononucleosis as a function of sibship constellation. Such an indirect hypothesis test is necessitated by the fact that age at primary Epstein-Barr virus infection is unknown for practically all people who have not experienced infectious mononucleosis. In this retrospective cohort study using nationwide registers, we followed all Danes born during the period 1971-2018 (n = 2 576 011) from 1977 to 2018 for hospital contacts with an infectious mononucleosis diagnosis (n = 23 905) or a multiple sclerosis diagnosis (n = 4442), defining two different end points. Relative risks (hazard ratios) of each end point as a function of sibship constellation were obtained from stratified Cox regression analyses. The hazard ratios of interest for infectious mononucleosis and multiple sclerosis could be assumed to be identical (test for homogeneity P = 0.19), implying that having siblings, especially of younger age, may protect a person against multiple sclerosis through early exposure to the Epstein-Barr virus. Maximum protection per sibling was obtained by having a 0-2 years younger sibling, corresponding to a hazard ratio of 0.80, with a 95% confidence interval of 0.76-0.85. The corresponding hazard ratio from having an (0-2 years) older sibling was 0.91 (0.86-0.96). Our results suggest that it may be possible essentially to eradicate multiple sclerosis using an Epstein-Barr virus vaccine administered before the teenage years. Getting there would require both successful replication of our study findings and, if so, elucidation of why early Epstein-Barr virus infection does not usually trigger the immune mechanisms responsible for the association between delayed Epstein-Barr virus infection and multiple sclerosis risk.

Epstein Barr Virus: Development of Vaccines and Immune Cell Therapy for EBV-Associated Diseases

Epstein-Barr virus (EBV) is the first human tumor virus discovered and is strongly implicated in the etiology of multiple lymphoid and epithelial cancers. Each year EBV associated cancers account for over 200,000 new cases of cancer and cause 150,000 deaths world-wide. EBV is also the primary cause of infectious mononucleosis, and up to 70% of adolescents and young adults in developed countries suffer from infectious mononucleosis. In addition, EBV has been shown to play a critical role in the pathogenesis of multiple sclerosis. An EBV prophylactic vaccine that induces neutralizing antibodies holds great promise for prevention of EBV associated diseases. EBV envelope proteins including gH/gL, gB and gp350 play key roles in EBV entry and infection of target cells, and neutralizing antibodies elicited by each of these proteins have shown to prevent EBV infection of target cells and markedly decrease EBV titers in the peripheral blood of humanized mice challenged with lethal dose EBV. Recent studies demonstrated that immunization with the combination of gH/gL, gB and/or gp350 induced markedly increased synergistic EBV neutralizing activity compared to immunization with individual proteins. As previous clinical trials focused on gp350 alone were partially successful, the inclusion of gH/gL and gB in a vaccine formulation with gp350 represents a promising approach of EBV prophylactic vaccine development. Therapeutic EBV vaccines have also been tested clinically with encouraging results. Immunization with various vaccine platforms expressing the EBV latent proteins EBNA1, LMP1, and/or LMP2 promoted specific CD4+ and CD8+ cytotoxic responses with anti-tumor activity. The addition of EBV envelope proteins gH/gL, gB and gp350 has the potential to increase the efficacy of a therapeutic EBV vaccine. The immune system plays a critical role in the control of tumors, and immune cell therapy has emerged as a promising treatment of cancers. Adoptive T-cell therapy has been successfully used in the prevention and treatment of post-transplant lymphoproliferative disorder. Chimeric antigen receptor T cell therapy and T cell receptor engineered T cell therapy targeting EBV latent proteins LMP1, LMP2 and/or EBNA1 have been in development, with the goal to increase the specificity and efficacy of treatment of EBV associated cancers.

Epstein-Barr virus infection after adolescence and human herpesvirus 6A as risk factors for multiple sclerosis

BACKGROUND AND PURPOSE

Infections with human herpesvirus 6A (HHV-6A) and Epstein-Barr virus (EBV) have been linked to multiple sclerosis (MS) development. For EBV, late infection has been proposed as a risk factor, but serological support is lacking. The objective of this study was to investigate how age affects the EBV and HHV-6A associated risks of developing MS.

METHODS

In this nested case-control study, Swedish biobanks were accessed to find pre-symptomatically collected blood samples from 670 individuals who later developed relapsing MS and 670 matched controls. A bead-based multiplex assay was used to determine serological response against EBV and HHV-6A. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals.

RESULTS

Seropositivity against EBV exhibited a pattern where associations switched from a decreased risk of developing MS in the group below 20 years of age to an increased risk amongst individuals aged 20-29 and 30-39 years (p for trend 0.020). The age of transition was estimated to be 18.8 years. In contrast, HHV-6A was associated with increased MS risk in all age groups (total cohort odds ratio 2.1, 95% confidence interval 1.6-2.7).

CONCLUSIONS

This study suggests EBV infection after adolescence and age independent HHV-6A infection as risk factors for MS.

Managing Epstein-Barr virus and other risk factors in MS-Future perspectives

Here, we discuss the rationale and feasibility of treatment directed against the modifiable risk factors in multiple sclerosis. The established environmental risk factors vitamin D insufficiency, cigarette smoke exposure, adolescence overweight, and Epstein-Barr virus infection are reviewed. Already available measures to target these risk factors are discussed.

MS and infections-Abandoned and surviving hypotheses

In this introduction, we follow the ups and downs of infections in MS pathogenesis. Our arguments focus on specific agents and events, not referring to general MS epidemiology. The historical approach continues on to contemporary data and a critical analysis.

Early hematopoiesis in multiple sclerosis patients

Contemporary evidence supports that MS immunopathology starts in the peripheral lymphatic system. However, the site and character of crucial initiating events are unknown. We examined subsets of the first stages of blood cells in the bone marrow of 9 MS patients and 11 neurologically healthy controls using FACS analysis. The proportion of natural killer T cells was lower (P=0.045) in the bone marrow of MS patients, but proportions of hematogenous stem cells, myeloblasts, and B cell precursor subsets in the bone marrow did not differ between MS patients and controls. In this pilot study with a limited number of samples we found no deviation of the early B cell lineage in bone marrow from MS patients.

Human endogenous retroviruses: friend or foe?

The integration of proviral DNA into host chromosomal DNA as an obligatory step in the replication cycle of retroviruses is a natural event of genetic recombination between virus and host. When integration occurs in cells of the germ line, it results in mendelian inheritance of viral sequences that we call endogenous retroviruses (ERV) and HERV for humans. HERVs and host often establish a symbiotic relationship, especially in the placenta and in pluripotent embryonic stem cells, but HERVs occasionally have deleterious consequences for the host. This special issue of APMIS features the fascinating relationships between HERV and humans in health and disease.

Multiple sclerosis and environmental factors: the role of vitamin D, parasites, and Epstein-Barr virus infection

Pathogenic mechanisms underlying multiple sclerosis development have yet to be clearly identified, but considerable evidence indicates that autoimmunity plays an important role in the etiology of the disease. It is generally accepted that autoimmune diseases like MS arise from complex interactions between genetic susceptibility and environmental factors. Although environmental factors unequivocally influencing MS development have yet to be established, accumulating evidence singles out several candidates, including sunlight-UV exposure or vitamin D deficiency, viral infections, hygiene, and cigarette smoking. Vitamin D deficiency has been associated with different autoimmune diseases. Several investigations indicate 125 (OH)2 vitamin D plays a critical role in shaping T-cell response and inducing T cells with immunosuppressive properties. Likewise, helminth infections represent another potential environmental factor exerting immunomodulatory properties. Both epidemiological and experimental data provide evidence to support autoimmune down-regulation secondary to parasite infections in patients with MS, through regulatory T- and B-cell action, with effects extending beyond simple response to an infectious agent. Finally, different epidemiological studies have demonstrated that Epstein-Barr virus infection confers added risk of developing MS. Proposed mechanisms responsible for this association include activation and expansion of self-reactive T and B cells, lower threshold for self-tolerance breakdown, and enhanced autoreactive B-cell survival, all to be discussed in this review. Understanding environmental factors influencing propensity to MS will lead to new and more effective approaches to prevent and treat the disease.

Vitamin D and multiple sclerosis—from epidemiology to prevention

In the present review, we discuss observational and experimental data suggesting a protective effect from sun exposure and/or vitamin D in multiple sclerosis (MS). These data include geographic variations in MS occurrence, temporal trends, genetics, biobank, and questionnaire data. We look more closely at the differentiation between general effects from UV exposure, and those of vitamin D per se, including plausible mechanisms of action. Finally, primary prevention is touched upon, and we suggest actions to be taken while awaiting the results from ongoing randomized controlled trials with vitamin D in MS.

Time trends in the incidence and prevalence of multiple sclerosis in Norway during eight decades

Norway has been subjected to numerous epidemiological investigations on the prevalence and incidence of multiple sclerosis (MS), dating back to 1935. The objective of this study was to review the studies on the prevalence and incidence of MS in Norway, provide an update on the prevalence of MS in Norway, and describe the time trends in the prevalence and incidence of MS in relation to risk factors, case ascertainment, and data. We performed a systematic search on PubMed and MEDLINE up to November 2014 using the search string ‘multiple sclerosis prevalence in Norway’ or ‘multiple sclerosis incidence in Norway’. In addition, we scrutinized the reference lists of the publications identified for relevant citations. We retrieved data on the distribution of MS in Norway on December 31, 2013 from the Norwegian Multiple Sclerosis Registry and Biobank and the Norwegian Patient Registry. We identified 29 articles. From 1961 to 2014, the reported prevalence of MS increased from 20 to 203 per 100,000 inhabitants, and the incidence increased from 1.9 to 8.0 per 100,000. The nationwide crude prevalence in Norway, based on the Norwegian Patient Registry, was 208 per 100,000 on December 31, 2013. The reported prevalence of MS in Norway has increased 10-fold, with several possible causes. During eight decades, neurological health services have generally become more accessible to the population, and transforming diagnostic criteria has made the diagnosis of MS more precise and valid. There have also been changes in lifestyle behavior and known risk factors, such as vitamin D and smoking, that might have contributed to the increased incidence of MS. A possible role of increased survival in MS needs to be examined further.

This article is commented on by Berg-Hansen et al, published in 132: 364–367 (DOI: 10.1111/ane.12489).

Immune response induced by Epstein-Barr virus and Mycobacterium avium subsp. paratuberculosis peptides in current and past infectious mononucleosis: a risk for multiple sclerosis?

BACKGROUND AND PURPOSE

Infectious mononucleosis (IM) caused by Epstein-Barr virus (EBV) has been associated with increased risk of multiple sclerosis (MS). However, the mechanism linking these pathologies is unclear. Different reports indicate the association of EBV, and recently Mycobacterium avium subsp. paratuberculosis (MAP), with MS. For a better understanding of the role of these pathogens, the host response induced by selected antigenic peptides in subjects with a history of IM that significantly increases the risk of MS was investigated.

METHODS

Both humoral and cell-mediated response against peptides able to induce a specific immune activation in MS patients deriving from lytic and latent EBV antigens BOLF1(305-320), EBNA1(400-413), from MAP MAP_4027(18-32), MAP_0106c(121-132) and from human proteins IRF5(424-434) and MBP(85-98) in subjects with current and past IM were examined.

RESULTS

EBNA1 and MAP_0106c peptides were able to induce a humoral immune response in subjects with a history of clinical IM in an independent manner. Moreover, these peptides were capable of inducing pro-inflammatory cytokine interferon γ by CD4+ and CD8+ T lymphocytes and interleukin 6 and tumour necrosis factor α by CD14+ monocyte cells.

CONCLUSION

Our results highlight that EBV and MAP may be involved independently in the same causal process leading to MS in subjects with a history of IM.

Conclusion: National incidence and risk factor assessments may become a basis for the evaluation of prevention trials – prospects from the Third Nordic MS Symposium

This symposium started with an overview of recent incidence and prevalence data from the Scandinavian national registers and continued with a critical analysis of several alleged risk factors for MS. These risk factors are constantly changing and therefore might explain current incidence changes. In addition, they may be the subject of preventive measures.

Amphetamine- and methamphetamine-induced hyperthermia: Implications of the effects produced in brain vasculature and peripheral organs to forebrain neurotoxicity

The adverse effects of amphetamine- (AMPH) and methamphetamine- (METH) induced hyperthermia on vasculature, peripheral organs and peripheral immune system are discussed. Hyperthermia alone does not produce amphetamine-like neurotoxicity but AMPH and METH exposures that do not produce hyperthermia (≥40°C) are minimally neurotoxic. Hyperthermia likely enhances AMPH and METH neurotoxicity directly through disruption of protein function, ion channels and enhanced ROS production. Forebrain neurotoxicity can also be indirectly influenced through the effects of AMPH- and METH- induced hyperthermia on vasculature. The hyperthermia and the hypertension produced by high doses amphetamines are a primary cause of transient breakdowns in the blood-brain barrier (BBB) resulting in concomitant regional neurodegeneration and neuroinflammation in laboratory animals. This BBB breakdown can occur in the amygdala, thalamus, striatum, sensory and motor cortex and hippocampus. Under these conditions, repetitive seizures greatly enhance neurodegeneration in hippocampus, thalamus and amygdala. Even when the BBB is less disrupted, AMPH- or METH- induced hyperthermia effects on brain vasculature may play a role in neurotoxicity. In this case, striatal and cortical vascular function are adversely affected, and even greater ROS, immune and damage responses are seen in the meninges and cortical surface vasculature. Finally, muscle and liver damage and elevated cytokines in blood can result when amphetamines produce hyperthermia. Proteins, from damaged muscle may activate the peripheral immune system and exacerbate liver damage. Liver damage can further increase cytokine levels, immune system activation and increase ammonia levels. These effects could potentially enhance vascular damage and neurotoxicity.