Epstein-Barr virus and multiple sclerosis

The Gut-Brain Axis: How Microbiota and Host Inflammasome Influence Brain Physiology and Pathology

The human microbiota has a fundamental role in host physiology and pathology. Gut microbial alteration, also known as dysbiosis, is a condition associated not only with gastrointestinal disorders but also with diseases affecting other distal organs. Recently it became evident that the intestinal bacteria can affect the central nervous system (CNS) physiology and inflammation. The nervous system and the gastrointestinal tract are communicating through a bidirectional network of signaling pathways called the gut-brain axis, which consists of multiple connections, including the vagus nerve, the immune system, and bacterial metabolites and products. During dysbiosis, these pathways are dysregulated and associated with altered permeability of the blood-brain barrier (BBB) and neuroinflammation. However, numerous mechanisms behind the impact of the gut microbiota in neuro-development and -pathogenesis remain poorly understood. There are several immune pathways involved in CNS homeostasis and inflammation. Among those, the inflammasome pathway has been linked to neuroinflammatory conditions such as multiple sclerosis, Alzheimer's and Parkinson's diseases, but also anxiety and depressive-like disorders. The inflammasome complex assembles upon cell activation due to exposure to microbes, danger signals, or stress and lead to the production of pro-inflammatory cytokines (interleukin-1β and interleukin-18) and to pyroptosis. Evidences suggest that there is a reciprocal influence of microbiota and inflammasome activation in the brain. However, how this influence is precisely working is yet to be discovered. Herein, we discuss the status of the knowledge and the open questions in the field focusing on the function of intestinal microbial metabolites or products on CNS cells during healthy and inflammatory conditions, such as multiple sclerosis, Alzheimer's and Parkinson's diseases, and also neuropsychiatric disorders. In particular, we focus on the innate inflammasome pathway as immune mechanism that can be involved in several of these conditions, upon exposure to certain microbes.

Association of infections with multiple sclerosis in Gulf Cooperation Council countries: a review

Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system, causing inflammation, demyelination, and neurodegeneration. Infection can play a role in its etiology. Herein, a review is presented of studies that have reported an association between infection and MS risk in countries of the Arabian Gulf region. Searches of the PubMed, Google Scholar, and Science Direct databases were carried out using various search terms, and relevant studies published through January 2019 on the epidemiology of MS in Gulf Cooperation Council countries identified. MS has been found to be associated with measles in Saudi Arabia and Epstein–Barr virus in Kuwait whereas no association has been identified between risk of MS and varicella-zoster virus, mumps, or human herpesvirus-6. However, few epidemiological studies on this topic have been conducted in countries of the Gulf region. Longitudinal and serological studies to establish robust evidence between infection and risk of MS are highly recommended, and a regional MS registry is needed.

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

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

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

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

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

Infection Elicited Autoimmunity and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: An Explanatory Model

Myalgic encephalomyelitis (ME) often also called chronic fatigue syndrome (ME/CFS) is a common, debilitating, disease of unknown origin. Although a subject of controversy and a considerable scientific literature, we think that a solid understanding of ME/CFS pathogenesis is emerging. In this study, we compiled recent findings and placed them in the context of the clinical picture and natural history of the disease. A pattern emerged, giving rise to an explanatory model. ME/CFS often starts after or during an infection. A logical explanation is that the infection initiates an autoreactive process, which affects several functions, including brain and energy metabolism. According to our model for ME/CFS pathogenesis, patients with a genetic predisposition and dysbiosis experience a gradual development of B cell clones prone to autoreactivity. Under normal circumstances these B cell offsprings would have led to tolerance. Subsequent exogenous microbial exposition (triggering) can lead to comorbidities such as fibromyalgia, thyroid disorder, and orthostatic hypotension. A decisive infectious trigger may then lead to immunization against autoantigens involved in aerobic energy production and/or hormone receptors and ion channel proteins, producing postexertional malaise and ME/CFS, affecting both muscle and brain. In principle, cloning and sequencing of immunoglobulin variable domains could reveal the evolution of pathogenic clones. Although evidence consistent with the model accumulated in recent years, there are several missing links in it. Hopefully, the hypothesis generates testable propositions that can augment the understanding of the pathogenesis of ME/CFS.

The genetics of multiple sclerosis in Latin America

Background

In today’s globalised world, the heterogeneity of diseases such as multiple sclerosis has been studied since it has been suggested that ethnic differences, in conjunction with geographical and environmental factors, influence its incidence and prevalence.

Aim

Based on this, an attempt has been made to identify the genetic factors that may confer risk or protection, not only for developing multiple sclerosis but also for determining the course of its evolution.

Results

In Latin America we have some data about this, which have been replicated in different populations in the entire region, with very different results compared with other regions, which could explain not only the different frequencies in some populations, such as Caucasians, but also the course of the disease and the response to actual treatments. However, in addition to these findings, other associated epigenetic mechanisms have also been found in our populations, such as levels of vitamin D, parasitic diseases, and indigenous populations. Therefore, the study of epigenetics plays a crucial role in understanding the physiopathology of multiple sclerosis. It must be studied in each population, especially in Latin America, due to its broad heterogeneity.

Conclusion

It is very important to understand not only the genetic and external factors with these very specific effects in multiple sclerosis patients, but also the way they interact and are able to explain the frequency and some specific phenotypes of the disease in our populations besides the posibility to be a very specific treatment target.

Experimental Models of Autoimmune Demyelinating Diseases in Nonhuman Primates

Human idiopathic inflammatory demyelinating diseases (IIDD) are a heterogeneous group of autoimmune inflammatory and demyelinating disorders of the central nervous system (CNS). These include multiple sclerosis (MS), the most common chronic IIDD, but also rarer disorders such as acute disseminated encephalomyelitis (ADEM) and neuromyelitis optica (NMO). Great efforts have been made to understand the pathophysiology of MS, leading to the development of a few effective treatments. Nonetheless, IIDD still require a better understanding of the causes and underlying mechanisms to implement more effective therapies and diagnostic methods. Experimental autoimmune encephalomyelitis (EAE) is a commonly used animal model to study the pathophysiology of IIDD. EAE is principally induced through immunization with myelin antigens combined with immune-activating adjuvants. Nonhuman primates (NHP), the phylogenetically closest relatives of humans, challenged by similar microorganisms as other primates may recapitulate comparable immune responses to that of humans. In this review, the authors describe EAE models in 3 NHP species: rhesus macaques ( Macaca mulatta), cynomolgus macaques ( Macaca fascicularis), and common marmosets ( Callithrix jacchus), evaluating their respective contribution to the understanding of human IIDD. EAE in NHP is a heterogeneous disease, including acute monophasic and chronic polyphasic forms. This diversity makes it a versatile model to use in translational research. This clinical variability also creates an opportunity to explore multiple facets of immune-mediated mechanisms of neuro-inflammation and demyelination as well as intrinsic protective mechanisms. Here, the authors review current insights into the pathogenesis and immunopathological mechanisms implicated in the development of EAE in NHP.

A complex role of herpes viruses in the disease process of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system (CNS). Neither the antigenic target(s) nor the cell population(s) responsible for CNS tissue destruction in MS have been fully defined. The objective of this study was to simultaneously determine the antigen (Ag)-specificity and phenotype of un-manipulated intrathecal CD4+ and CD8+ T cells of patients with relapsing-remitting and progressive MS compared to subjects with other inflammatory neurological diseases. We applied a novel Ag-recognition assay based on co-cultures of freshly obtained cerebrospinal fluid T cells and autologous dendritic cells pre-loaded with complex candidate Ag's. We observed comparably low T cell responses to complex auto-Ag's including human myelin, brain homogenate, and cell lysates of apoptotically modified oligodendroglial and neuronal cells in all cohorts and both compartments. Conversely, we detected a strong intrathecal enrichment of Epstein-Barr virus- and human herpes virus 6-specific (but not cytomegalovirus-specific) reactivities of the Th1-phenotype throughout all patients. Qualitatively, the intrathecal enrichment of herpes virus reactivities was more pronounced in MS patients. This enrichment was completely reversed by long-term treatment with the IL-2 modulating antibody daclizumab, which strongly inhibits MS disease activity. Finally, we observed a striking discrepancy between diminished intrathecal T cell proliferation and enhanced cytokine production of herpes virus-specific T cells among progressive MS patients, consistent with the phenotype of terminally differentiated cells. The data suggest that intrathecal administration of novel therapeutic agents targeting immune cells outside of the proliferation cycle may be necessary to effectively eliminate intrathecal inflammation in progressive MS.

Epstein-Barr virus infection induces aberrant TLR activation pathway and fibroblast-myofibroblast conversion in scleroderma

Scleroderma (SSc) is a complex and heterogeneous connective tissue disease mainly characterized by autoimmunity, vascular damage, and fibrosis that mostly involve the skin and lungs. Epstein–Barr virus (EBV) is a lymphotropic γ-herpesvirus that has co-evolved with human species, infecting >95% of the adult population worldwide, and has been a leading candidate in triggering several autoimmune diseases. Here we show that EBV establishes infection in the majority of fibroblasts and endothelial cells in the skin of SSc patients, characterized by the expression of the EBV noncoding small RNAs (EBERs) and the increased expression of immediate-early lytic and latency mRNAs and proteins. We report that EBV is able to persistently infect human SSc fibroblasts in vitro, inducing an aberrant innate immune response in infected cells. EBV–Toll-like receptor (TLR) aberrant activation induces the expression of selected IFN-regulatory factors (IRFs), IFN-stimulated genes (ISGs), transforming growth factor-β1 (TGFβ1), and several markers of fibroblast activation, such as smooth muscle actin and Endothelin-1, and all of these genes play a key role in determining the profibrotic phenotype in SSc fibroblasts. These findings imply that EBV infection occurring in mesenchymal, endothelial, and immune cells of SSc patients may underlie the main pathological features of SSc including autoimmunity, vasculopathy, and fibrosis, and provide a unified disease mechanism represented by EBV reactivation.

Epstein-Barr virus persistence and infection of autoreactive plasma cells in synovial lymphoid structures in rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis (RA) is associated with an increased Epstein-Barr virus (EBV) blood DNA load, a robust immune response to EBV and cross-reactive circulating antibodies to viral and self-antigens. However, the role of EBV in RA pathogenesis remains elusive. Here, we investigated the relationship between synovial EBV infection, ectopic lymphoid structures (ELS) and immunity to citrullinated self and EBV proteins.

METHODS

Latent and lytic EBV infection was investigated in 43 RA synovial tissues characterised for presence/absence of ELS and in 11 control osteoarthritis synovia using RT-PCR, in situ hybridisation and immunohistochemistry. Synovial production of anti-citrullinated protein (ACPA) and anti-citrullinated EBV peptide (VCP1/VCP2) antibodies was investigated in situ and in vivo in the severe combined immunodeficiency (SCID)/RA chimeric model.

RESULTS

EBV dysregulation was observed exclusively in ELS+ RA but not osteoarthritis (OA) synovia, as revealed by presence of EBV latent (LMP2A, EBV-encoded small RNA (EBER)) transcripts, EBER+ cells and immunoreactivity for EBV latent (LMP1, LMP2A) and lytic (BFRF1) antigens in ELS-associated B cells and plasma cells, respectively. Importantly, a large proportion of ACPA-producing plasma cells surrounding synovial germinal centres were infected with EBV. Furthermore, ELS-containing RA synovia transplanted into SCID mice supported production of ACPA and anti-VCP1/VCP2 antibodies. Analysis of CD4+ and CD8+ T-cell localisation and granzyme B expression suggests that EBV persistence in ELS-containing synovia may be favoured by exclusion of CD8+ T cells from B-cell follicles and impaired CD8-mediated cytotoxicity.

CONCLUSIONS

We demonstrated active EBV infection within ELS in the RA synovium in association with local differentiation of ACPA-reactive B cells.

Epstein-Barr virus infection is common in inflamed gastrointestinal mucosa

BACKGROUND AND AIMS

Epstein-Barr virus (EBV) is present in the malignant epithelial cells of 10% of all gastric adenocarcinomas; however, localization of the virus in normal gastrointestinal mucosa is largely unexplored. In the present study, we measured EBV DNA and localized viral gene products in gastritis specimens (n = 89), normal gastric and colonic mucosa (n = 14), Crohn's disease (n = 9), and ulcerative colitis (n = 11) tissues.

METHODS

A battery of sensitive and specific quantitative polymerase chain reactions targeted six disparate regions of the EBV genome: BamH1 W, EBNA1, LMP1, LMP2, BZLF1, and EBER1. EBV infection was localized by EBV-encoded RNA (EBER) in situ hybridization and by immunohistochemical stains for viral latent proteins LMP1 and LMP2 and for viral lytic proteins BMRF1 and BZLF1. B lymphocytes were identified using CD20 immunostains.

RESULTS

EBV DNA was essentially undetectable in normal gastric mucosa but was present in 46% of gastritis lesions, 44% of normal colonic mucosa, 55% of Crohn's disease, and 64% of ulcerative colitis samples. Levels of EBV DNA exceeded what would be expected based on the numbers of B lymphocytes in inflamed tissues, suggesting that EBV is preferentially localized to inflammatory gastrointestinal lesions. Histochemical staining revealed EBER expression in lymphoid cells of some PCR-positive lesions. The viral lytic viral proteins, BMRF1 and BZLF1, were expressed in lymphoid cells of two ulcerative colitis tissues, both of which had relatively high viral loads by quantitative PCR.

CONCLUSION

EBV-infected lymphocytes are frequently present in inflamed gastric and colonic mucosa. Active viral replication in some lesions raises the possibility of virus-related perpetuation of gastrointestinal inflammation.

Autoimmunity, dendritic cells and relevance for Parkinson's disease

Innate and adaptive immune responses in neurodegenerative diseases have become recently a focus of research and discussions. Parkinson’s disease (PD) is a neurodegenerative disorder without known etiopathogenesis. The past decade has generated evidence for an involvement of the immune system in PD pathogenesis. Both inflammatory and autoimmune mechanisms have been recognized and studies have emphasized the role of activated microglia and T-cell infiltration. In this short review, we focus on dendritic cells, on their role in initiation of autoimmune responses, we discuss aspects of neuroinflammation and autoimmunity in PD, and we report new evidence for the involvement of neuromelanin in these processes.

Exacerbated metastatic disease in a mouse mammary tumor model following latent gammaherpesvirus infection

Background

Controversy exists as to the ability of human gammaherpesviruses to cause or exacerbate breast cancer disease in patients. The difficulty in conducting definitive human studies can be overcome by investigating developing breast cancer in a mouse model. In this study, we utilized mice latently infected with murine gammaherpesvirus 68 (HV-68) to question whether such a viral burden could exacerbate metastatic breast cancer disease using a mouse mammary tumor model.

Results

Mice latently infected with HV-68 had a similar primary tumor burden, but much greater metastatic disease, when compared to mock treated mice given the transplantable tumor, 4 T1. This was true for lung lesions, as well as secondary tumor masses. Increased expression of pan-cytokeratin and VEGF-A in tumors from HV-68 infected mice was consistent with increased metastatic disease in these animals. Surprisingly, no viral particles could be cultured from tumor tissues, and the presence of viral DNA or RNA transcripts could not be detected in primary or secondary tumor tissues.

Conclusions

Latent HV-68 infection had no significant effect on the size of primary 4 T1 mammary tumors, but exacerbated the number of metastatic lung lesions and secondary tumors when compared to mock treated mice. Increased expression of the tumor marker, pan-cytokeratin, and VEGF-A in tumors of mice harboring latent virus was consistent with an exacerbated metastatic disease. Mechanisms responsible for this exacerbation are indirect, since no virus could be detected in cancerous tissues.

Murine gammaherpesvirus 68 infection protects lupus-prone mice from the development of autoimmunity

Gammaherpesvirus infections, such as those caused by EBV, have been suggested to promote the development of autoimmunity. To test this idea, we infected healthy WT and lupus-prone B6.Sle123 mice with an EBV-related and rodent-specific gammaherpesvirus, γHV68. Although acute γHV68 infection increased autoantibody levels for 4 to 6 wk, latent infection inhibited these responses for 1 y. The inhibition of autoantibody expression was only observed in B6.Sle123 females and not in males, which already displayed lower autoantibody titers. Contrary to the initial hypothesis, infection of young B6.Sle123 mice, both male and female, resulted in suppression of lymphoid activation and expansion and of glomerular inflammation and sclerosis, preserving kidney function. Moreover, γHV68 infection led to reduced autoantibody titers, lymphoid activation, and glomerular inflammation whether lupus-prone females were infected before or during disease manifestation. Finally, γHV68 infection also inhibited autoantibody production in the genetically distinct MRL/lpr lupus-prone mice. Our findings indicate that γHV68 infection strongly inhibits the development and progression of lupus-like disease in mice that spontaneously develop this condition mediating its beneficial effects at the humoral, cellular, and organ levels. The mechanisms by which the virus exerts this down-modulatory action are not yet clear, but appear to operate via reduced activation of dendritic cells, T cells, and B cells. Gammaherpesviruses coevolved with the vertebrate immune systems, establishing lifelong infections in humans and other mammals. Our findings that γHV68 infection prevents rather than exacerbates autoimmunity in mice suggest that infection with gammaherpesviruses may be protective rather than pathological in most individuals.

Multiple sclerosis: where will we be in 2020?

The past decade has seen a surge of research interest in multiple sclerosis and an accelerated expansion of investigative efforts into multiple sclerosis therapeutics. Investigators have continued dissecting the complex immunological perturbations that may contribute to the disease and made major advances in understanding the genetics of multiple sclerosis. This article addresses current investigative issues and offers predictions about where the understanding and treatment of multiple sclerosis may stand at the end of the 21st century's second decade.

Antibodies to infectious agents and the positive symptom dimension of subclinical psychosis: The TRAILS study

Infections have been suggested to play a role in the etiology of schizophrenia, but the evidence for this has been inconsistent. Schizophrenia patients have an increased risk of infections as a result of hospitalizations or life style factors. Therefore a study on early subclinical manifestations of psychosis in relation to virus infections is warranted. We examined whether serum antibodies against human Herpes viruses and Toxoplasma gondii were associated with subclinical symptoms of psychosis in adolescents. Data were collected as part of the TRacking Adolescents' Individual Lives Survey (TRAILS) cohort, a large prospective cohort of Dutch adolescents. A total of 1176 participants with an available Community Assessment of Psychic Experiences (CAPE) and an available blood sample were included in this analysis. Solid-enzyme immunoassay methods were used to measure the presence of immunoglobulin G (IgG) antibodies in serum to the Herpes virus family and to T. gondii. There was no significant association between serologic evidence of infection with human Herpes viruses or T. gondii and the risk of subclinical positive experience of psychosis. Subjects with a positive serological reaction to Epstein-Barr Virus (EBV) had higher scores on the positive dimension of psychosis measured by CAPE (b=0.03, P=0.02). This significant association was observed in males, but not in females. The current study suggests that there is no significant association between serological evidence of infection to human Herpes viruses and positive subclinical experience of psychosis, whereas there was an association between EBV infection and subclinical psychotic symptoms in boys.

Infectious mononucleosis-linked HLA class I single nucleotide polymorphism is associated with multiple sclerosis

Background: Multiple sclerosis is a presumed autoimmune disease associated with genetic and environmental risk factors such as infectious mononucleosis. Recent research has shown infectious mononucleosis to be associated with a specific HLA class I polymorphism.

Objectives: Our aim was to test if the infectious mononucleosis-linked HLA class I single nucleotide polymorphism (rs6457110) is also associated with multiple sclerosis.

Methods: Genotyping of the HLA-A single nucleotide polymorphism rs6457110 using TaqMan was performed in 591 multiple sclerosis cases and 600 controls. The association of multiple sclerosis with the HLA-A single nucleotide polymorphism was tested using logistic regression adjusted for age, sex and HLA-DRB1*1501.

Results: HLA-A minor allele (A) is associated with multiple sclerosis (OR = 0.68; p = 4.08 × 10 -5). After stratification for HLA-DRB1*1501 risk allele (T) carrier we showed a significant OR of 0.70 ( p = 0.003) for HLA-A.

Conclusions: HLA class I single nucleotide polymorphism rs6457110 is associated with infectious mononucleosis and multiple sclerosis, independent of the major class II allele, supporting the hypothesis that shared genetics may contribute to the association between infectious mononucleosis and multiple sclerosis.

Alternative splicing in multiple sclerosis and other autoimmune diseases

Alternative splicing is a general mechanism for regulating gene expression that affects the RNA products of more than 90% of human genes. Not surprisingly, alternative splicing is observed among gene products of metazoan immune systems, which have evolved to efficiently recognize pathogens and discriminate between "self" and "non-self", and thus need to be both diverse and flexible. In this review we focus on the specific interface between alternative splicing and autoimmune diseases, which result from a malfunctioning of the immune system and are characterized by the inappropriate reaction to self-antigens. Despite the widespread recognition of alternative splicing as one of the major regulators of gene expression, the connections between alternative splicing and autoimmunity have not been apparent. We summarize recent findings connecting splicing and autoimmune disease, and attempt to find common patterns of splicing regulation that may advance our understanding of autoimmune diseases and open new avenues for therapy.

Interferon induced with helicase C domain 1 (IFIH1) and virus-induced autoimmunity: a review

In addition to genetic factors, environmental triggers, including viruses and other pathogens, are thought to play a major role in the development of autoimmune disease. Recent findings have shown that viral-induced autoimmunity is likely to be genetically determined. In large-scale genetic analyses, an association of interferon induced with helicase C domain 1 (IFIH1) gene variants encoding a viral RNA-sensing helicase with susceptibility to several autoimmune diseases was found. To date, the precise role of IFIH1 in pathogenic mechanisms of viral-induced autoimmunity has yet to be fully elucidated. However, recent reports suggest that IFIH1 may play a role in the etiology of type 1 diabetes. Rare IFIH1 alleles have been shown to be protective against diabetes, and their carriage correlates with lower production of this helicase and its functional disruption. In contrast, upregulation of IFIH1 expression by viruses is associated with more severe disease, and could exacerbate the autoimmune process in susceptible individuals.

Potential triggers of MS

MS is an immune mediated disease of the central nervous system (CNS) characterized by demyelination, axonal damage and neurologic disability. The primary cause of this CNS disease remains elusive. Here we will address our current understanding of the role of viruses as potential environmental triggers for MS. Virus infections can act peripherally (outside the CNS) or within the CNS. The association of viral infections with demyelinating disease, in both animals and humans, will be discussed, as will the potential contributions of peripheral infection with Torque Teno virus, infection outside of and/or within the CNS with Epstein-Barr virus and infection within the CNS with Human Herpesvirus 6 to MS. An experimental animal model, Theiler's murine encephalomyelitis virus infection of susceptible strains of mice is an example of viral infections of the CNS as a prerequisite for demyelination. Finally, the proposition that multiple virus infections are required, which first prime the immune system and then trigger the disease, as a model where infections outside of the CNS lead to inflammatory changes within the CNS, for the development of a MS-like disease is explored.

An overview of gene-epigenetic-environmental contributions to MS causation

In this paper we review how environmental factors might interact with genes and epigenetic factors to trigger multiple sclerosis (MS), the latter probably by immune-mediated mechanisms.

Variations of the perforin gene in patients with multiple sclerosis

Perforin is involved in cell-mediated cytotoxicity and mutations of its gene (PRF1) cause familial hemophagocytic lymphohistiocytosis (FLH2). PRF1 sequencing in 190 patients with multiple sclerosis and 268 controls detected two FLH2-associated variations (A91V, N252S) in both groups and six novel mutations (C999T, G1065A, G1428A, A1620G, G719A, C1069T) in patients. All together, carriers of these variations were more frequent in patients than in controls (phenotype frequency: 17 vs 9%, P=0.0166; odds ratio (OR)=2.06, 95% confidence interval (CI): 1.13-3.77). Although A91V was the most frequent variation and displayed a trend of association with multiple sclerosis (MS) in the first population of patients and controls (frequency of the 91V allele: 0.076 vs 0.043, P=0.044), we used it as a marker to confirm PRF1 involvement in MS and assessed its frequency in a second population of 966 patients and 1520 controls. Frequency of the 91V allele was significantly higher in patients than in controls also in the second population (0.075 vs 0.058%, P=0.019). In the combined cohorts of 1156 patients and 1788 controls, presence of the 91V allele in single or double dose conferred an OR=1.38 (95% CI=1.10-1.74). These data suggest that A91V and possibly other perforin variations indicate susceptibility to MS.

Herpes virus antibodies seroprevalence in children with autoimmune thyroid disease

BACKGROUND

Elevated titers of antibodies against different herpes virus antigens have been reported in some immunodeficient and systemic autoimmune disorders.

OBJECTIVE

To examine if Herpes Simplex Virus (HSV), Epstein-Barr virus (EBV), and cytomegalovirus (CMV) IgG and IgM antibodies are detected more frequently in children with autoimmune thyroid disease (AITD) compared to controls.

SUBJECTS AND METHODS

Thirty-four children with AITD, aged 9.62 +/- 2.35 years, and 31 matched controls, aged 9.24 +/- 2.98 years, were studied.

RESULTS

The percentage of EBV IgG+ children with AITD was statistically higher than the percentage of EBV IgG+ controls (82.35% versus 51.61%, P = 0.008). The percentage of EBV IgG+ children with AITD and hypothyroidism was statistically higher than the percentage of EBV IgG+ children with AITD, without hypothyroidism (100% versus 70%, P = 0.024). No other statistically significant differences were observed in HSV-1+2, and CMV IgG or IgM antibodies between the subgroups of children studied.

CONCLUSIONS

EBV seroprevalence is higher in children with AITD compared to controls and the underlying pathology remains to be elucidated.

Association of Epstein-Barr virus antibody titers with a human IL-10 promoter polymorphism in Japanese women

Background

Multiple sclerosis (MS) risk, over 10-fold higher in Western than in Asian countries, is associated with elevated IgG antibody titers against Epstein-Barr viral capcid antigen (anti-EBVCA IgG titers). Given the 84% homology of the open reading frame BCRF1 of Epstein-Barr virus (EBV) to human interleukin 10 (hIL-10) and the remarkable Caucasian-vs.-Asian population differences in hIL-10 gene promoter polymorphisms, this strong association of MS risk with anti-EB-VCA IgG titers may be explained by the genetic variations in the hIL-10 gene.

Methods

We evaluated anti-EB-VCA IgG titers in association with a single nucleotide polymorphism (SNP) in the promoter of hIL-10 at position -819 (hIL-10 T-819C) in a cross-sectional survey of 241 Japanese. Anti-EB-VCA IgG titer and its elevation (≥ 1:160) were evaluated, stratified by sex and hIL-10 T-819C genotype.

Results

The cytosine-allele frequencies at hIL-10 T-819C were 32.9% in women and 30.9% in men. These are consistent with the published reports of Japanese and Chinese, but substantially lower than those of Caucasians (> 70%). In women, the proportion with elevated anti-EB-VCA IgG titers (≥ 1:160) increased appreciably from 53.7% in the T/T genotype group to 66.7% in the T/C group and to 83.3% in the C/C group (P-trend = 0.037). The titers did not differ by the hIL-10 T-819C genotype in men.

Conclusion

Anti-EB-VCA IgG titers may increase with the number of cytosine alleles at hIL-10 T-819C in women. This observed gender specific association in Japanese warrants further investigation, especially in Western populations with high MS risk.

Viral infection can induce the production of autoantibodies

PURPOSE OF REVIEW

To review the current literature and summarize the main principles found between viral infections and the subsequent production of autoantibodies.

RECENT FINDINGS

We concentrate on recent findings involving three viral agents, one of which is Epstein-Barr virus, which has been associated with many autoimmune diseases and is classically considered to induce systemic lupus erythematosus. As we will discuss, this occurs through molecular mimicry between Epstein-Barr virus nuclear antigen 1 and lupus-specific antigens such as Ro, La or dsDNA, through induction of Toll-like receptor hypersensitivity by Epstein-Barr virus latent membrane protein 2A or by creating immortal B and T cells by loss of apoptosis. Hepatitis B virus was found to share amino acid sequences with different autoantigens. Tissue damage and the release of intracellular components is just another example of the autoantibody production caused by this virus. Cytomegalovirus has often been controversially associated with several autoimmune diseases and, although is the least understood viral infection of the three, appears to be somewhat suspicious.

SUMMARY

Understanding the infectious origin of autoimmune diseases is important as we aim to identify high-risk patients and disrupt this process with vaccines or other medications, ultimately delaying or even preventing the evolution of autoimmune diseases.