Epstein-Barr virus and systemic lupus erythematosus

Neoself-antigens are the primary target for autoreactive T cells in human lupus

Major histocompatibility complex class II (MHC-II) is the most significant genetic risk factor for systemic lupus erythematosus (SLE), but the nature of the self-antigens that trigger autoimmunity remains unclear. Unusual self-antigens, termed neoself-antigens, are presented on MHC-II in the absence of the invariant chain essential for peptide presentation. Here, we demonstrate that neoself-antigens are the primary target for autoreactive T cells clonally expanded in SLE. When neoself-antigen presentation was induced by deleting the invariant chain in adult mice, neoself-reactive T cells were clonally expanded, leading to the development of lupus-like disease. Furthermore, we found that neoself-reactive CD4+ T cells were significantly expanded in SLE patients. A high frequency of Epstein-Barr virus reactivation is a risk factor for SLE. Neoself-reactive lupus T cells were activated by Epstein-Barr-virus-reactivated cells through downregulation of the invariant chain. Together, our findings imply that neoself-antigen presentation by MHC-II plays a crucial role in the pathogenesis of SLE.

Assessment of the humoral immune status of varicella-zoster virus in patients with diffuse connective tissue diseases

Background

Diffuse connective tissue diseases (DCTDs) require long-term immunosuppressive treatment, increasing the risk of varicella-zoster virus (VZV) infection. This study aims to evaluate the humoral immune status against VZV in DCTD patients and explore factors that may influence their immune levels.

Methods

This is a retrospective cohort study that collected data from adult DCTD patients (≥18 years) attending our outpatient clinic. The geometric mean concentration (GMC) of VZV-specific IgG antibodies in the patients' sera was measured using the enzyme-linked immunosorbent assay (ELISA).

Results

A total of 280 RA patients, 272 SLE + MCTD patients and 280 healthy controls were included. SLE + MCTD patients had significantly higher VZV IgG antibody levels than RA patients (p < 0.05) but showed no significant difference compared to healthy controls (p > 0.05). Notable differences were observed particularly among female patients and those aged 30-49 years, (p < 0.05). SLE + MCTD patients in an active disease state had significantly higher VZV IgG antibody titers than RA patients (p < 0.05). Additionally, patients with a history of herpes zoster, regardless of being in the SLE + MCTD, RA, or control group, exhibited higher VZV IgG titers (p < 0.05).

Conclusion

Although DCTD patients, particularly those with SLE and MCTD, exhibit higher VZV IgG antibody levels, they still face a higher risk of developing herpes zoster (HZ), which may be related to their underlying disease and immunosuppressive treatment. The presence of antibodies alone may not provide complete protection, necessitating consideration of cellular immune mechanisms. It is recommended to enhance monitoring of VZV antibody levels in high-risk patients and consider herpes zoster vaccination to reduce HZ-related complications.

Auto-immuno-deficiency syndromes

Autoimmune diseases constitute a broad, heterogenous group with many diverse and often overlapping symptoms. Even so, they are traditionally classified as either systemic, rheumatic diseases or organ-directed diseases. Several theories exist about autoimmune diseases, including defective self-recognition, altered self, molecular mimicry, bystander activation and epitope spreading. While there is no consensus about these theories, it is generally accepted that genetic, pre-disposing factors in combination with environmental factors can result in autoimmune disease. The relative contribution of genetic and environmental factors varies between diseases, as does the significance of individual contributing factors within related diseases. Among the genetic factors, molecules involved in antigen (Ag) recognition, processing, and presentation stand out (e.g., MHC I and II) together with molecules involved in immune signaling and regulation of cellular interactions (i.e., immuno-phenotypes). Also, various immuno-deficiencies have been linked to development of autoimmune diseases. Among the environmental factors, infections (e.g., viruses) have attracted most attention, but factors modulating the immune system have also been the subject of much research (e.g., sunlight and vitamin D). Multiple sclerosis currently stands out due to a very strong and proven association with Epstein-Barr virus infection, notably in cases of late infection and in cases of EBV-associated mononucleosis. Thus, a common picture is emerging that both systemic and organ-directed autoimmune diseases may appropriately be described as auto-immuno-deficiency syndromes (AIdeSs), a concept that emphasizes and integrates existing knowledge on the role of immuno-deficiencies and chronic infections with development of overlapping disease syndromes with variable frequencies of autoantibodies and/or autoreactive T cells. This review integrates and exemplifies current knowledge on the interplay of genetically determined immuno-phenotypes and chronic infections in the development of AIdeSs.

Human herpesvirus reactivation and its potential role in the pathogenesis of post-acute sequelae of SARS-CoV-2 infection

The emergence of SARS-CoV-2 has precipitated a global pandemic with substantial long-term health implications, including the condition known as post-acute sequelae of SARS-CoV-2 infection (PASC), commonly referred to as Long COVID. PASC is marked by persistent symptoms such as fatigue, neurological issues, and autonomic dysfunction that persist for months beyond the acute phase of COVID-19. This review examines the potential role of herpesvirus reactivation, specifically Epstein-Barr virus (EBV) and cytomegalovirus (CMV), in the pathogenesis of PASC. Elevated antibody titers and specific T cell responses suggest recent herpesvirus reactivation in some PASC patients, although viremia is not consistently detected. SARS-CoV-2 exhibits endothelial trophism, directly affecting the vascular endothelium and contributing to microvascular pathologies. These pathologies are significant in PASC, where microvascular dysfunction may underlie various chronic symptoms. Similarly, herpesviruses like CMV also exhibit endothelial trophism, which may exacerbate endothelial damage when reactivated. Evidence suggests that EBV and CMV reactivation could indirectly contribute to the immune dysregulation, immunosenescence, and autoimmune responses observed in PASC. Additionally, EBV may play a role in the genesis of neurological symptoms through creating mitochondrial dysfunction, though direct confirmation remains elusive. The reviewed evidence suggests that while herpesviruses may not play a direct role in the pathogenesis of PASC, their potential indirect effects, especially in the context of endothelial involvement, warrant further investigation.

Epstein-Barr Viruses: Their Immune Evasion Strategies and Implications for Autoimmune Diseases

Epstein-Barr virus (EBV), a member of the γ-herpesvirus family, is one of the most prevalent and persistent human viruses, infecting up to 90% of the adult population globally. EBV's life cycle includes primary infection, latency, and lytic reactivation, with the virus primarily infecting B cells and epithelial cells. This virus has evolved sophisticated strategies to evade both innate and adaptive immune responses, thereby maintaining a lifelong presence within the host. This persistence is facilitated by the expression of latent genes such as EBV nuclear antigens (EBNAs) and latent membrane proteins (LMPs), which play crucial roles in viral latency and oncogenesis. In addition to their well-known roles in several types of cancer, including nasopharyngeal carcinoma and B-cell lymphomas, recent studies have identified the pathogenic roles of EBV in autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. This review highlights the intricate interactions between EBV and the host immune system, underscoring the need for further research to develop effective therapeutic and preventive strategies against EBV-associated diseases.

The role of Epstein-Barr virus in autoimmune and autoinflammatory diseases

Epstein-Barr Virus (EBV), a dsDNA herpesvirus, is believed to play a significant role in exacerbating and potentially triggering autoimmune and autoinflammatory maladies. Around 90% of the world is infected with the virus, which establishes latency within lymphocytes. EBV is also known to cause infectious mononucleosis, a self-limited flu-like illness, in adolescents. EBV is often reactivated and it employs several mechanisms of evading the host immune system. It has also been implicated in inducing host immune dysfunction potentially resulting in exacerbation or triggering of inflammatory processes. EBV has therefore been linked to a number of autoimmune diseases, including systemic lupus erythematosus, multiple sclerosis, rheumatoid arthritis, and Sjögren's syndrome. The review examines the molecular mechanisms through which the virus alters host immune system components thus possibly resulting in autoimmune processes. Understanding the mechanisms underpinning EBV-associated autoimmunity is pivotal; however, the precise causal pathways remain elusive. Research on therapeutic agents and vaccines for EBV has been stagnant for a long number of years until recent advances shed light on potential therapeutic targets. The implications of EBV in autoimmunity underscore the importance of developing targeted therapeutic strategies and, potentially, vaccines to mitigate the autoimmune burden associated with this ubiquitous virus.

An IL-17A-centric response to Epstein-Barr virus DNA mediated by dendritic Cell-T cell interactions

Introduction: The Epstein-Barr virus has been associated with a considerable number of autoimmune diseases. We have previously demonstrated that EBV DNA enhances the production of IL-17A, a pro-inflammatory cytokine, via endosomal Toll-like receptor signalling. Methods: We used RNA-seq to analyze the transcriptional profile of mouse immune cells treated with EBV DNA. Results: We observed that EBV DNA upregulates an IL-17A-centric network of mediators. Ensemble Gene Set Enrichment Analysis (EGSEA) showed enriched expression of sets involved in inflammatory responses including IFNγ and TNF-α-associated pathways as well as proinflammatory diseases. On the other hand, while macrophages and B cells were somewhat able to induce an IL-17A response from T cells to EBV DNA, they were less potent than dendritic cells. EBV virions were also capable of eliciting the production of inflammatory mediators from dendritic cell-T cell cultures largely mirroring responses to the viral DNA. Conclusions: Given the wide prevalence of EBV in the population, our analyses reveal a network of mediators and cell types that may serve as therapeutic targets in a large proportion of people affected by autoimmune diseases.

Sex differences in symptomatology and immune profiles of Long COVID

Strong sex differences in the frequencies and manifestations of Long COVID (LC) have been reported with females significantly more likely than males to present with LC after acute SARS-CoV-2 infection 1-7 . However, whether immunological traits underlying LC differ between sexes, and whether such differences explain the differential manifestations of LC symptomology is currently unknown. Here, we performed sex-based multi-dimensional immune-endocrine profiling of 165 individuals 8 with and without LC in an exploratory, cross-sectional study to identify key immunological traits underlying biological sex differences in LC. We found that female and male participants with LC experienced different sets of symptoms, and distinct patterns of organ system involvement, with female participants suffering from a higher symptom burden. Machine learning approaches identified differential sets of immune features that characterized LC in females and males. Males with LC had decreased frequencies of monocyte and DC populations, elevated NK cells, and plasma cytokines including IL-8 and TGF-β-family members. Females with LC had increased frequencies of exhausted T cells, cytokine-secreting T cells, higher antibody reactivity to latent herpes viruses including EBV, HSV-2, and CMV, and lower testosterone levels than their control female counterparts. Testosterone levels were significantly associated with lower symptom burden in LC participants over sex designation. These findings suggest distinct immunological processes of LC in females and males and illuminate the crucial role of immune-endocrine dysregulation in sex-specific pathology.

Antibody Cross-Reactivity in Auto-Immune Diseases

Autoimmunity is defined by the presence of antibodies and/or T cells directed against self-components. Although of unknown etiology, autoimmunity commonly is associated with environmental factors such as infections, which have been reported to increase the risk of developing autoimmune diseases. Occasionally, similarities between infectious non-self and self-tissue antigens may contribute to immunological cross-reactivity in autoimmune diseases. These reactions may be interpreted as molecular mimicry, which describes cross-reactivity between foreign pathogens and self-antigens that have been reported to cause tissue damage and to contribute to the development of autoimmunity. By focusing on the nature of antibodies, cross-reactivity in general, and antibody-antigen interactions, this review aims to characterize the nature of potential cross-reactive immune reactions between infectious non-self and self-tissue antigens which may be associated with autoimmunity but may not actually be the cause of disease onset.

Virus-Derived Small RNAs and microRNAs in Health and Disease

MicroRNAs (miRNAs) are short noncoding RNAs that can regulate all steps of gene expression (induction, transcription, and translation). Several virus families, primarily double-stranded DNA viruses, encode small RNAs (sRNAs), including miRNAs. These virus-derived miRNAs (v-miRNAs) help the virus evade the host's innate and adaptive immune system and maintain an environment of chronic latent infection. In this review, the functions of the sRNA-mediated virus-host interactions are highlighted, delineating their implication in chronic stress, inflammation, immunopathology, and disease. We provide insights into the latest viral RNA-based research-in silico approaches for functional characterization of v-miRNAs and other RNA types. The latest research can assist toward the identification of therapeutic targets to combat viral infections.

Differential impact of environmental factors on systemic and localized autoimmunity

The influence of environmental factors on the development of autoimmune disease is being broadly investigated to better understand the multifactorial nature of autoimmune pathogenesis and to identify potential areas of intervention. Areas of particular interest include the influence of lifestyle, nutrition, and vitamin deficiencies on autoimmunity and chronic inflammation. In this review, we discuss how particular lifestyles and dietary patterns may contribute to or modulate autoimmunity. We explored this concept through a spectrum of several autoimmune diseases including Multiple Sclerosis (MS), Systemic Lupus Erythematosus (SLE) and Alopecia Areata (AA) affecting the central nervous system, whole body, and the hair follicles, respectively. A clear commonality between the autoimmune conditions of interest here is low Vitamin D, a well-researched hormone in the context of autoimmunity with pleiotropic immunomodulatory and anti-inflammatory effects. While low levels are often correlated with disease activity and progression in MS and AA, the relationship is less clear in SLE. Despite strong associations with autoimmunity, we lack conclusive evidence which elucidates its role in contributing to pathogenesis or simply as a result of chronic inflammation. In a similar vein, other vitamins impacting the development and course of these diseases are explored in this review, and overall diet and lifestyle. Recent work exploring the effects of dietary interventions on MS showed that a balanced diet was linked to improvement in clinical parameters, comorbid conditions, and overall quality of life for patients. In patients with MS, SLE and AA, certain diets and supplements are linked to lower incidence and improved symptoms. Conversely, obesity during adolescence was linked with higher incidence of MS while in SLE it was associated with organ damage. Autoimmunity is thought to emerge from the complex interplay between environmental factors and genetic background. Although the scope of this review focuses on environmental factors, it is imperative to elaborate the interaction between genetic susceptibility and environment due to the multifactorial origin of these disease. Here, we offer a comprehensive review about the influence of recent environmental and lifestyle factors on these autoimmune diseases and potential translation into therapeutic interventions.

Persistent SARS-CoV-2 Infection, EBV, HHV-6 and Other Factors May Contribute to Inflammation and Autoimmunity in Long COVID

A novel syndrome called long-haul COVID or long COVID is increasingly recognized in a significant percentage of individuals within a few months after infection with SARS-CoV-2. This disorder is characterized by a wide range of persisting, returning or even new but related symptoms that involve different tissues and organs, including respiratory, cardiac, vascular, gastrointestinal, musculo-skeletal, neurological, endocrine and systemic. Some overlapping symptomatologies exist between long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Very much like with long ME/CFS, infections with herpes family viruses, immune dysregulation, and the persistence of inflammation have been reported as the most common pattern for the development of long COVID. This review describes several factors and determinants of long COVID that have been proposed, elaborating mainly on viral persistence, reactivation of latent viruses such as Epstein-Barr virus and human herpesvirus 6 which are also associated with the pathology of ME/CFS, viral superantigen activation of the immune system, disturbance in the gut microbiome, and multiple tissue damage and autoimmunity. Based on these factors, we propose diagnostic strategies such as the measurement of IgG and IgM antibodies against SARS-CoV-2, EBV, HHV-6, viral superantigens, gut microbiota, and biomarkers of autoimmunity to better understand and manage this multi-factorial disorder that continues to affect millions of people in the world.

Integrative Bioinformatics Analysis Identifies DDX60 as a Potential Biomarker for Systemic Lupus Erythematosus

Background

Systemic lupus erythematosus (SLE) is an autoimmune disease with strong heterogeneity, leading to variable clinical symptoms, which makes diagnosis and activity evaluation difficult.

Methods

The original dataset of GSE88884 was analyzed to screen differentially expressed genes (DEGs) of SLE and the correlation between DEGs and clinical parameters (SLEDAI, anti-dsDNA, C3, and C4). The result was validated by microarray GSE121239 and SLE patients with RT-qPCR. Next, receiver operator characteristic (ROC) analysis, correlation analysis, and ordinal logistic regression were applied, respectively, to evaluate the capability of diagnosis and prediction of the candidate biomarker. Subsequently, the biological functions of the candidate biomarker were investigated through KEGG and GO enrichment, protein-protein interaction network, and the correlation matrix.

Results

A total of 283 DEGs were screened, and seven of them were overlapped with SLE-related genes. DDX60 was identified as the candidate biomarker. Analyses of GSE88884, GSE121239, and SLE patients with RT-qPCR indicated that DDX60 expression level is significantly higher in patients with high disease activity. ROC analysis and the area under the ROC curve (AUC = 0.8818) suggested that DDX60 has good diagnostic performance. DDX60 expression level was positively correlated with SLEDAI scores (r = 0.24). For every 1-unit increase in DDX60 expression value, the odds of a higher stage of activity of SLE disease are multiplied by 1.47. The function of DDX60 mainly focuses on IFN-I-induced antiviral activities, RIG-I signaling, and innate immune. Moreover, DDX60 plays a synergistic role with DDX58, IFIH1, OASL, IFIT1, and other related genes in the SLE pathogenesis. Conclusions. DDX60 is differently expressed in SLE, and it is significantly related to both serological indicators and the disease activity of SLE. We suggested that DDX60 might be a potential biomarker for SLE diagnosis and management.

MOPA: An integrative multi-omics pathway analysis method for measuring omics activity

Pathways are composed of proteins forming a network to represent specific biological mechanisms and are often used to measure enrichment scores based on a list of genes in means to measure their biological activity. The pathway analysis is a de facto standard downstream analysis procedure in most genomic and transcriptomic studies. Here, we present MOPA (Multi-Omics Pathway Analysis), which is a multi-omics integrative method that scores individual pathways in a sample wise manner in terms of enriched multi-omics regulatory activity, which we refer to mES (multi-omics Enrichment Score). The mES score reflects the strength of regulatory relations between multi-omics in units of pathways. In addition, MOPA is able to measure how much each omics contribute to mES that may be used to observe what kind of omics are active in a pathway within a sample group (e.g., subtype, gender), which we refer to OCR (Omics Contribution Rate). Using nine different cancer types, 93 clinical features and three types of omics (i.e., gene expression, miRNA and methylation), MOPA was used to search for clinical features that were explainable in context of multi-omics. By evaluating the performance of MOPA, we showed that it yielded higher or at least equal performance compared to previous single and multi-omics pathway analysis tools. We find that the advantage of MOPA is the ability to explain pathways in terms of omics relation using mES and OCR. As one of the results, the TGF-beta signaling pathway was captured as an important pathway that showed distinct mES and OCR values specific to the CMS4 subtype in colon adenocarcinoma. The mES and OCR metrics suggested that the mRNA and miRNA expressions were significantly different from the other subtypes, which was concordant with previous studies. The MOPA software is available at https://github.com/jaeminjj/MOPA.

Clinical characteristics of SLE patients infected with Epstein-Barr virus and potential associated risk factors

OBJECTIVE

To investigate the clinical features and potential associated risk factors of Epstein-Barr virus (EBV) DNA positivity in systemic lupus erythematosus (SLE) patients.

METHODS

A total of 121 newly diagnosed SLE patients who had never used immunosuppressive drugs (treatment-naïve) and 191 previously treated SLE patients from January 2017 to January 2020 were enrolled in this study. And 115 age- and sex-matched non-rheumatic disease controls were also included.

RESULTS

A significantly higher incidence of EBV DNA positivity and higher viral DNA copies in peripheral blood mononuclear cells were observed among treatment-naïve and previously treated SLE patients compared with controls. The positivity rate of EBV DNA was further increased in previously treated SLE patients compared with that in treatment-naïve patients. EBV DNA-positive treatment-naïve SLE patients presented lower incidence of hemolytic anemia and more affected organ number than EBV DNA-negative patients. EBV DNA-positive treated SLE patients showed older age, longer immunosuppressive duration, higher IgG level, and higher Th/Ts ratio than EBV DNA-negative patients. Patients responding well to treatment with decreased SLE disease activity index scores had a transformation of EBV DNA from positive to negative in treated SLE patients. Multivariate logistic regression analysis showed that older age, higher IgG level, and longer immunosuppressive duration were associated risk factors for EBV DNA positivity in SLE patients, while higher TNF-α level was a protective factor.

CONCLUSION

Older age, higher IgG level, and longer immunosuppressive duration are associated with the positivity of EBV DNA in SLE patients. A seroconversion of EBV DNA indicates an association between EBV positivity and therapy response, while larger number cases are needed to confirm. Key Points • Older age, higher IgG level, and longer immunosuppressive duration are associated with EBV DNA positivity in SLE patients. • A seroconversion of EBV DNA might be an indicator to reflect the SLE therapy -response.

Antiviral Innate Immune Responses in Autoimmunity: Receptors, Pathways, and Therapeutic Targeting

Innate immune receptors sense nucleic acids derived from viral pathogens or self-constituents and initiate an immune response, which involves, among other things, the secretion of cytokines including interferon (IFN) and the activation of IFN-stimulated genes (ISGs). This robust and well-coordinated immune response is mediated by the innate immune cells and is critical to preserving and restoring homeostasis. Like an antiviral response, during an autoimmune disease, aberrations of immune tolerance promote inflammatory responses to self-components, such as nucleic acids and immune complexes (ICs), leading to the secretion of cytokines, inflammation, and tissue damage. The aberrant immune response within the inflammatory milieu of the autoimmune diseases may lead to defective viral responses, predispose to autoimmunity, or precipitate a flare of an existing autoimmune disease. Herein, we review the literature on the crosstalk between innate antiviral immune responses and autoimmune responses and discuss the pitfalls and challenges regarding the therapeutic targeting of the mechanisms involved.

Altered B cell phenotype and CD27+ memory B cells are associated with clinical features and environmental exposure in Colombian systemic lupus erythematosus patients

Background

B lymphocytes are dysregulated in Systemic Lupus Erythematosus (SLE) including the expansion of extrafollicular B cells in patients with SLE of African American ancestry, which is associated with disease activity and nephritis. The population of Colombia has a mixture of European, Native American, and African ancestry. It is not known if Colombian patients have the same B cell distributions described previously and if they are associated with disease activity, clinical manifestations, and environmental exposures.

Objective

To characterize B cell phenotype in a group of Colombian Systemic Lupus Erythematosus patients with mixed ancestry and determine possible associations with disease activity, clinical manifestations, the DNA methylation status of the IFI44L gene and environmental exposures.

Materials and methods

Forty SLE patients and 17 healthy controls were recruited. Cryopreserved peripheral B lymphocytes were analyzed by multiparameter flow cytometry, and the DNA methylation status of the gene IFI44L was evaluated in resting Naive B cells (rNAV).

Results

Extrafollicular active Naive (aNAV) and Double Negative type 2, DN2 (CD27− IgD− CD21− CD11c+) B cells were expanded in severe active patients and were associated with nephritis. Patients had hypomethylation of the IFI44L gene in rNAV cells. Regarding environmental exposure, patients occupationally exposed to organic solvents had increased memory CD27+ cells (SWM).

Conclusion

aNAV and DN2 extrafollicular cells showed significant clinical associations in Colombian SLE patients, suggesting a relevant role in the disease’s pathophysiology. Hypomethylation of the IFI44L gene in resting Naive B cells suggests that epigenetic changes are established at exceedingly early stages of B cell ontogeny. Also, an alteration in SWM memory cells was observed for the first time in patients exposed to organic solvents. This opens different clinical and basic research possibilities to corroborate these findings and deepen the knowledge of the relationship between environmental exposure and SLE.

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

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

CD4+ Cytotoxic T Cells Involved in the Development of EBV-Associated Diseases

Activated cytotoxic CD4 T cells (HLA-DR+) play an important role in the control of EBV infection, especially in cells with latency I (EBNA-1). One of the evasion mechanisms of these latency cells is generated by gp42, which, via peripherally binding to the β1 domain of the β chain of MHC class II (HLA-DQ, -DR, and -DP) of the infected B lymphocyte, can block/alter the HLA class II/T-cell receptor (TCR) interaction, and confer an increased level of susceptibility towards the development of EBV-associated autoimmune diseases or cancer in genetically predisposed individuals (HLA-DRB1* and DQB1* alleles). The main developments predisposing the factors of these diseases are: EBV infection; HLA class II risk alleles; sex; and tissue that is infiltrated with EBV-latent cells, forming ectopic lymphoid structures. Therefore, there is a need to identify treatments for eliminating cells with EBV latency, because the current treatments (e.g., antivirals and rituximab) are ineffective.

Autophagy in lupus nephritis: A delicate balance between regulation and disease

Autophagy is a highly regulated process wherein an unwanted cargo of damaged and dysfunctional cytoplasmic components is removed, delivered to lysosomes for degradation, and released back into the cytoplasm. Accumulating evidence suggests an important role of autophagy in the pathophysiology of systemic lupus erythematosus, with profound effects on both innate and adaptive immunity. Autophagy downregulation results in the inhibition of antigen presenting cells, reduced release of neutrophil extracellular traps and decreased activation of effector T and B cells, leading to reduced autoantibody production and attenuated type 1 interferon signaling. However, defective autophagy may accelerate the production of other inflammatory cytokines and reduce the clearance of apoptotic cells, promoting lupus development. In addition, autophagy dysfunction can concur to the pathogenesis of kidney injury in lupus nephritis. Autophagy is a pivotal mechanism to maintain podocyte integrity and endothelial cell survival. Several animal models have demonstrated that defective autophagy leads to podocyte injury and can promote an endothelial pro-inflammatory and atherogenic phenotype. Moreover, autophagy is a key homeostatic regulator of renal tubular cells, and recent evidence has pointed out that chronic autophagy deficiency may accelerate kidney fibrosis. Targeting autophagy may theoretically improve lupus nephritis outcomes, but novel, non-invasive methods to measure and monitor autophagic activity are urgently needed. In addition, the extent and timing of autophagy inhibition still require additional studies before clinical translation may be attempted. In this review, we will also discuss the effect of several clinically available drugs that can regulate the autophagic flux and their effect in lupus nephritis patients.

The Role of Exposomes in the Pathophysiology of Autoimmune Diseases II: Pathogens

In our continuing examination of the role of exposomes in autoimmune disease, we use this review to focus on pathogens. Infections are major contributors to the pathophysiology of autoimmune diseases through various mechanisms, foremost being molecular mimicry, when the structural similarity between the pathogen and a human tissue antigen leads to autoimmune reactivity and even autoimmune disease. The three best examples of this are oral pathogens, SARS-CoV-2, and the herpesviruses. Oral pathogens reach the gut, disturb the microbiota, increase gut permeability, cause local inflammation, and generate autoantigens, leading to systemic inflammation, multiple autoimmune reactivities, and systemic autoimmunity. The COVID-19 pandemic put the spotlight on SARS-CoV-2, which has been called “the autoimmune virus.” We explore in detail the evidence supporting this. We also describe how viruses, in particular herpesviruses, have a role in the induction of many different autoimmune diseases, detailing the various mechanisms involved. Lastly, we discuss the microbiome and the beneficial microbiota that populate it. We look at the role of the gut microbiome in autoimmune disorders, because of its role in regulating the immune system. Dysbiosis of the microbiota in the gut microbiome can lead to multiple autoimmune disorders. We conclude that understanding the precise roles and relationships shared by all these factors that comprise the exposome and identifying early events and root causes of these disorders can help us to develop more targeted therapeutic protocols for the management of this worldwide epidemic of autoimmunity.

Association of Human Leucocyte Antigen Class II, with viral load and immune response to Epstein-Barr virus in adult and pediatric Systemic lupus erythematosus patients

OBJECTIVE

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease, which is known to be associated with HLA-DRB1 and Epstein-Barr virus (EBV) infection. In the Indian subcontinent where there is high seroendemicity of EBV, we postulated that the association of this virus in adult SLE (aSLE) and pediatric SLE (pSLE) patients would be different and differentially associate with the HLA-DRB1 susceptibility and protective genes.

METHODS

A total of 109 aSLE, 52 pSLE, 215 adult healthy and 63 pediatric healthy controls were recruited. HLA-DRB1 genotyping by PCR-SSP, EBV load estimation by real-time PCR and antibody profiling (IgG & IgM) to EBV antigens by line blot assay were performed.

RESULTS

DRB1*15 was found predominant in pSLE patients and DRB1*03 in aSLE patients. DRB1*15/X heterozygous was predominant in overall SLE patients, although disease severity, like hypocomplementemia, higher autoantibody levels and more organ involvement was observed in *15/*15 homozygous state. EBV strongly associated with pSLE patients showing higher percent of EA-D IgG (p < 0.0001) and p22 IgG (p = 0.035) along with higher viral load (p = 0.001) as compared to healthy controls. In addition, the higher EBV DNA load significantly associated with anti-EA-D IgG (p = 0.013) and DRB1*15/*15 (p = 0.007) in pSLE patients as compared to aSLE patients.

CONCLUSIONS

This study therefore indicates that different HLA-DRB1 allotypes confer susceptibility to SLE in children and adults and disease may be triggered by increased EBV reactivation.

A High Prevalence of Anti-EBNA1 Heteroantibodies in Systemic Lupus Erythematosus (SLE) Supports Anti-EBNA1 as an Origin for SLE Autoantibodies

Background

That Epstein–Barr virus (EBV) infection is associated with systemic lupus erythematosus (SLE) is established. The challenge is to explain mechanistic roles EBV has in SLE pathogenesis. Previous studies identify four examples of autoantibody cross-reactions between SLE autoantigens and Epstein–Barr nuclear antigen 1 (EBNA1). For two of these examples, the earliest detected autoantibody specifically cross-reacts with EBNA1; thereby, defined EBNA1 epitopes induce a robust autoantibody response in animals. These results suggest that the autoantibodies initiating the process leading to SLE may emerge from the anti-EBNA1 heteroimmune response. If this hypothesis is true, then anti-EBNA1 responses would be more frequent in EBV-infected SLE patients than in EBV-infected controls. We tested this prediction.

Methods

We evaluated published East Asian data by selecting those with a positive anti-viral capsid antigen (VCA) antibody immunoglobulin G (IgG) test and determining whether anti-EBNA1 was more common among the EBV-infected SLE cases than among matched EBV-infected controls with conditional logistic regression analysis.

Results

All the qualifying SLE patients (100%) in this dataset were EBV-infected compared to age- and sex-matched controls (92.2%) [odds ratio (OR) = 28.6, 95% CI 6.4–∞, p = 8.83 × 10^-8], confirming the known close association of EBV infection with SLE. Furthermore, virtually all the SLE cases have both anti-VCA IgG and anti-EBNA1 IgG antibodies [124 of 125 (99.2%)], which are more frequently present than in age- and sex-matched EBV-infected controls [232 of 250 (93.2%)] (OR = 9.7, 95% CI 1.5–414, p = 0.0078) for an 89.7% SLE attributable risk from anti-EBNA1, which is in addition to the 100% SLE risk attributable to EBV infection in these data.

Conclusions

The association of EBV infection with SLE is reconfirmed. The prediction that anti-EBNA1 is more frequent in these SLE cases than in EBV-infected controls is true, consistent with the hypothesis that anti-EBNA1 contributes to SLE. This second EBV-dependent risk factor is consistent with a molecular mimicry model for the generation of SLE, starting with EBV infection, progressing to anti-EBNA1 response; then molecular mimicry leads to anti-EBNA1 antibodies cross-reacting with an SLE autoantigen, causing autoantibody epitope spreading, and culminating in clinical SLE. These results support the anti-EBNA1 heteroimmune response being a foundation from which pathogenic SLE autoimmunity emerges.

Renal autoimmunity: The role of bacterial and viral infections, an extensive review

Autoimmunity is a process by which the loss of self-tolerance results in an immune attack against the body own tissues and organs. For autoimmunity to occur, various elements serving as triggers were described by which infections are considered one of the leading factors. In turn, renal involvement in autoimmune diseases, whether by an organ-specific attack, or as part of a systemic disease process, is well known. As bacterial and viral infections are considered to be common triggers for autoimmunity in general, we aimed to study their association with renal autoimmunity in particular. We performed an extensive search of the recent and relevant medical literature regarding renal autoimmunity syndromes such as infection-associated glomerulonephritis and vasculitis, associated with bacterial and viral infections. By utilizing PubMed and Google Scholar search engines, over 200 articles and case reports were reviewed. Among other mechanisms, direct infection of the renal parenchyma, molecular mimicry, induction of B-cells or secretion of superantigens, bacterial and viral pathogens were found to correlate with the development of renal autoimmunity. Nevertheless, this was not true for all pathogens, as some mimic autoimmune diseases and others show a surprisingly protective effect. The exact immunopathogenesis is yet to be determined, however. For conclusion, bacterial and viral infections are linked to renal autoimmunity by both direct damage and as mediators of systemic diseases. Further research particularly on the immunopathogenetic mechanisms of renal autoimmunity associated with infections is required.

Serologic markers of Epstein-Barr virus reactivation are associated with increased disease activity, inflammation, and interferon pathway activation in patients with systemic lupus erythematosus

SLE is a clinically heterogeneous disease characterized by an unpredictable relapsing-remitting disease course. Although the etiology and mechanisms of SLE flares remain elusive, Epstein-Barr virus (EBV) reactivation is implicated in SLE pathogenesis. This study examined the relationships between serological measures of EBV reactivation, disease activity, and interferon (IFN)-associated immune pathways in SLE patients. Sera from adult SLE patients (n = 175) and matched unaffected controls (n = 47) were collected and tested for antibodies against EBV-viral capsid antigen (EBV-VCA; IgG and IgA), EBV-early antigen (EBV-EA; IgG), cytomegalovirus (CMV; IgG), and herpes simplex virus (HSV-1; IgG). Serological evidence of EBV reactivation was more common in SLE patients compared to controls as demonstrated by seropositivity to EBV-EA IgG (39% vs 13%; p = 0.0011) and EBV-VCA IgA (37% vs 17%; p = 0.018). EBV-VCA, CMV1, and HSV-1 IgG seropositivity rates did not differ between SLE patients and controls. Furthermore, concentrations of EBV-VCA (IgG and IgA) and EBV-EA (IgG) were higher in SLE patients. SLE patients with high disease activity had increased concentrations of EBV-VCA IgA (mean ISR 1.34 vs. 0.97; p = 0.041) and EBV-EA IgG levels (mean ISR 1.38 vs. 0.90; p = 0.007) compared with those with lower disease activity. EBV reactivation was associated with enhanced levels of the IFN-associated molecule IP-10 (p < 0.001) and the soluble mediators BLyS (p < 0.001) and IL-10 (p = 0.0011). In addition, EBV-EA IgG responses were enriched in two previously defined patient clusters with robust expression of IFN and inflammatory or lymphoid and monocyte responses. Patients in these clusters were also more likely to have major organ involvement, such as renal disease. This study supports a possible role for EBV reactivation in SLE disease activity.

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Serologic markers of EBV reactivation are more common in SLE patients.

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Elevated EBV reactivation is associated with higher SLE disease activity.

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EBV serologic reactivation correlates with elevated IP-10, IL-10, and BLyS levels.

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EBV reactivation occurs in SLE clusters with robust inflammatory and IFN responses.

Genetic and transcriptomic analyses support a switch to lytic phase in Epstein Barr virus infection as an important driver in developing Systemic Lupus Erythematosus

To investigate the molecular mechanisms through which Epstein-Barr virus (EBV) may contribute to Systemic Lupus Erythematosus (SLE) pathogenesis, we interrogated SLE genetic risk loci for signatures of EBV infection. We first compared the gene expression profile of SLE risk genes across 459 different cell/tissue types. EBV-infected B cells (LCLs) had the strongest representation of highly expressed SLE risk genes. By determining an SLE risk allele effect on gene expression (expression quantitative trait loci, eQTL) in LCLs and 16 other immune cell types, we identified 79 SLE risk locus:gene pairs putatively interacting with EBV infection. A total of 10 SLE risk genes from this list (CD40, LYST, JAZF1, IRF5, BLK, IKZF2, IL12RB2, FAM167A, PTPRC and SLC15A) were targeted by the EBV transcription factor, EBNA2, differentially expressed between LCLs and B cells, and the majority were also associated with EBV DNA copy number, and expression level of EBV encoded genes. Our final gene network model based on these genes is suggestive of a nexus involving SLE risk loci and EBV latency III and B cell proliferation signalling pathways. Collectively, our findings provide further evidence to support the interaction between SLE risk loci and EBV infection that is in part mediated by EBNA2. This interplay may increase the tendency towards EBV lytic switching dependent on the presence of SLE risk alleles. These results support further investigation into targeting EBV as a therapeutic strategy for SLE.

Epstein-Barr Virus and the Origin of Myalgic Encephalomyelitis or Chronic Fatigue Syndrome

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) affects approximately 1% of the general population. It is a chronic, disabling, multi-system disease for which there is no effective treatment. This is probably related to the limited knowledge about its origin. Here, we summarized the current knowledge about the pathogenesis of ME/CFS and revisit the immunopathobiology of Epstein-Barr virus (EBV) infection. Given the similarities between EBV-associated autoimmune diseases and cancer in terms of poor T cell surveillance of cells with EBV latency, expanded EBV-infected cells in peripheral blood and increased antibodies against EBV, we hypothesize that there could be a common etiology generated by cells with EBV latency that escape immune surveillance. Albeit inconclusive, multiple studies in patients with ME/CFS have suggested an altered cellular immunity and augmented Th2 response that could result from mechanisms of evasion to some pathogens such as EBV, which has been identified as a risk factor in a subset of ME/CFS patients. Namely, cells with latency may evade the immune system in individuals with genetic predisposition to develop ME/CFS and in consequence, there could be poor CD4 T cell immunity to mitogens and other specific antigens, as it has been described in some individuals. Ultimately, we hypothesize that within ME/CFS there is a subgroup of patients with DRB1 and DQB1 alleles that could confer greater susceptibility to EBV, where immune evasion mechanisms generated by cells with latency induce immunodeficiency. Accordingly, we propose new endeavors to investigate if anti-EBV therapies could be effective in selected ME/CFS patients.

Identification of viral-mediated pathogenic mechanisms in neurodegenerative diseases using network-based approaches

During the course of a viral infection, virus-host protein-protein interactions (PPIs) play a critical role in allowing viruses to replicate and survive within the host. These interspecies molecular interactions can lead to viral-mediated perturbations of the human interactome causing the generation of various complex diseases. Evidences suggest that viral-mediated perturbations are a possible pathogenic etiology in several neurodegenerative diseases (NDs). These diseases are characterized by chronic progressive degeneration of neurons, and current therapeutic approaches provide only mild symptomatic relief; therefore, there is unmet need for the discovery of novel therapeutic interventions. In this paper, we initially review databases and tools that can be utilized to investigate viral-mediated perturbations in complex NDs using network-based analysis by examining the interaction between the ND-related PPI disease networks and the virus-host PPI network. Afterwards, we present our theoretical-driven integrative network-based bioinformatics approach that accounts for pathogen-genes-disease-related PPIs with the aim to identify viral-mediated pathogenic mechanisms focusing in multiple sclerosis (MS) disease. We identified seven high centrality nodes that can act as disease communicator nodes and exert systemic effects in the MS-enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways network. In addition, we identified 12 KEGG pathways, 5 Reactome pathways and 52 Gene Ontology Immune System Processes by which 80 viral proteins from eight viral species might exert viral-mediated pathogenic mechanisms in MS. Finally, our analysis highlighted the Th17 differentiation pathway, a disease communicator node and part of the 12 underlined KEGG pathways, as a key viral-mediated pathogenic mechanism and a possible therapeutic target for MS disease.

Epstein-Barr Virus in Salivary Samples from Systemic Lupus Erythematosus Patients with Oral Lesions

In order to investigate the possible role of Epstein-Barr virus (EBV) in systemic lupus erythematosus (SLE) and its associated oral lesions, a pilot case-control study was performed. A total of 31 patients (18 females and 13 males) were enrolled in the study and divided into two groups: group A included 16 patients with diagnosis of SLE and group B included 15 healthy individuals. Salivary swab samples were collected and subjected to molecular screening by real-time quantitative PCR (qPCR) for the detection of EBV DNA. EBV DNA was significantly detected in 8/16 (50%) SLE patients and in 5/7 (71.4%) subjects with SLE-associated oral lesions. Since EBV is one of the most common viruses in the human population, it is difficult to understand if it is the causative agent of SLE or, vice versa, if SLE is able to trigger the reactivation of EBV. This study highlights a significant association between the presence of EBV and both SLE and SLE-related oral lesions and provides rationale for further investigation into the role of EBV in SLE pathogenesis.

Viral infection in thymoma and thymic tumors with autoimmune diseases

A thymoma is a type of thymic tumor which is rarely malignant that is frequently reported in adult patients. A number of thymoma-related immune disorders are observed including autoimmune diseases, which suggests a strong connection between thymoma development and immunological mechanisms. Characterized by association with humoral and cellular immunodeficiency, thymoma patients are susceptible to opportunistic infections by environmental factors. Recent reports have suggested that viral infection may play a role in the etiological mechanisms of thymoma development associated with dysregulated immunity. In this review, we summarize the case reports and studies related to viral infection, such as CMV, EBV and HSV, that probably play a part in the pathogenesis of thymoma and related diseases. Furthermore, we demonstrate the underlying mechanisms by which viruses may induce the occurrence of thymoma with autoimmune diseases. Lastly, we discuss the potential application of antiviral therapy in the treatment of thymic diseases.

Molecular Properties and Therapeutic Targeting of the EBV-Encoded Receptor BILF1

The γ-herpesvirus Epstein-Barr Virus (EBV) establishes lifelong infections in approximately 90% of adults worldwide. Up to 1,000,000 people yearly are estimated to suffer from health conditions attributed to the infection with this virus, such as nasopharyngeal and gastric carcinomas as well as several forms of B, T and NK cell lymphoma. To date, no EBV-specific therapeutic option has reached the market, greatly reducing the survival prognoses of affected patients. Similar to other herpesviruses, EBV encodes for a G protein-coupled receptor (GPCR), BILF1, affecting a multitude of cellular signaling pathways. BILF1 has been identified to promote immune evasion and tumorigenesis, effectively ensuring a life-long persistence of EBV in, and driving detrimental health conditions to its host. This review summarizes the epidemiology of EBV-associated malignancies, their current standard-of-care, EBV-specific therapeutics in development, GPCRs and their druggability, and most importantly consolidates the findings of over 15 years of research on BILF1 in the context of EBV-specific drug development. Taken together, BILF1 constitutes a promising target for the development of novel EBV-specific therapeutics.

Age-related Epstein-Barr Virus-associated Lymphoproliferative Disorder Masquerading as Systemic Lupus Erythematosus

Age-related Epstein-Barr virus (EBV)-positive B-cell lymphoproliferative disorder (LPD) occurs in elderly patients without immunodeficiency. An 81-year-old woman without any known immunodeficiency was examined for fever, rash, arthritis, thrombocytopenia, pleural and pericardial effusions, lymphadenopathy, and positive autoantibodies, which satisfied the classification criteria for systemic lupus erythematosus (SLE). However, a lymph node biopsy revealed EBV-LPD, and she was diagnosed with age-related EBV-LPD. In young individuals, EBV infection is a major differential diagnosis of SLE, but to our knowledge, this is the first reported case of age-related EBV-LPD mimicking SLE. We should therefore consider EBV-related disorders in the differential diagnosis of SLE even in elderly individuals.

Cellular and molecular mechanisms breaking immune tolerance in inborn errors of immunity

In addition to susceptibility to infections, conventional primary immunodeficiency disorders (PIDs) and inborn errors of immunity (IEI) can cause immune dysregulation, manifesting as lymphoproliferative and/or autoimmune disease. Autoimmunity can be the prominent phenotype of PIDs and commonly includes cytopenias and rheumatological diseases, such as arthritis, systemic lupus erythematosus (SLE), and Sjogren's syndrome (SjS). Recent advances in understanding the genetic basis of systemic autoimmune diseases and PIDs suggest an at least partially shared genetic background and therefore common pathogenic mechanisms. Here, we explore the interconnected pathogenic pathways of autoimmunity and primary immunodeficiency, highlighting the mechanisms breaking the different layers of immune tolerance to self-antigens in selected IEI.

Humoral Immunity to Varicella Zoster Virus in Patients with Systemic Lupus Erythematosus and Rheumatoid Arthritis Compared to Healthy Controls

Background: The prevalence of herpes zoster (HZ) is high in patients with rheumatic diseases. Systemic lupus erythematosus (SLE) doubles the risk for developing HZ. However, little is known about natural humoral immunity against varicella zoster virus (VZV) in patients with SLE. Hence, we compared VZV IgG antibody concentrations in a group of SLE patients with healthy controls and patients with rheumatoid arthritis (RA). Methods: n = 56 patients with SLE, n = 54 patients with RA, and n = 56 healthy controls were included in this study. The VZV IgG antibody concentration was measured using an enzyme-linked immunosorbent assay (ELISA). The antibody concentrations were compared between the groups. Results: Overall IgG antibody titers for VZV in SLE patients were comparable to healthy controls but higher when compared to patients with rheumatoid arthritis (p = 0.0012). In consequence, antibody levels in controls were higher than in RA patients (p = 0.0097). Stratification by age revealed highest titers among SLE patients in the fourth life decade (p = 0.03 for controls, p = 0.0008 for RA patients) whereas RA patients in their sixth decade had the lowest antibody concentration (p = 0.03 for controls, p = 0.04 for SLE patients). Regarding the individual HZ history, antibody levels of SLE patients with a positive history exceeded all other groups. Conclusions: Although humoral VZV immunity in SLE patients is comparable to healthy controls it seems to be pronounced in young SLE patients between 30 and 39. The lowest VZV IgG levels were found in RA patients. HZ seems to induce antibody production, particularly in patients with SLE. Immunological processes might contribute to VZV antibody levels in SLE patients, but further investigations are needed to substantiate this hypothesis. Even though the increased HZ prevalence seems to be independent of humoral immunity in SLE patients, reduced humoral immunity might contribute to HZ in RA patients. The available HZ subunit vaccination might be an appropriate way to reduce the HZ risk in patients with rheumatic diseases.

Global discovery of lupus genetic risk variant allelic enhancer activity

Genome-wide association studies of Systemic Lupus Erythematosus (SLE) nominate 3073 genetic variants at 91 risk loci. To systematically screen these variants for allelic transcriptional enhancer activity, we construct a massively parallel reporter assay (MPRA) library comprising 12,396 DNA oligonucleotides containing the genomic context around every allele of each SLE variant. Transfection into the Epstein-Barr virus-transformed B cell line GM12878 reveals 482 variants with enhancer activity, with 51 variants showing genotype-dependent (allelic) enhancer activity at 27 risk loci. Comparison of MPRA results in GM12878 and Jurkat T cell lines highlights shared and unique allelic transcriptional regulatory mechanisms at SLE risk loci. In-depth analysis of allelic transcription factor (TF) binding at and around allelic variants identifies one class of TFs whose DNA-binding motif tends to be directly altered by the risk variant and a second class of TFs that bind allelically without direct alteration of their motif by the variant. Collectively, our approach provides a blueprint for the discovery of allelic gene regulation at risk loci for any disease and offers insight into the transcriptional regulatory mechanisms underlying SLE.

Thousands of genetic variants have been associated with lupus, but causal variants and mechanisms are unknown. Here, the authors combine a massively parallel reporter assay with genome-wide ChIP experiments to identify risk variants with allelic enhancer activity mediated through transcription factor binding.

Viral Infections and Systemic Lupus Erythematosus: New Players in an Old Story

A causal link between viral infections and autoimmunity has been studied for a long time and the role of some viruses in the induction or exacerbation of systemic lupus erythematosus (SLE) in genetically predisposed patients has been proved. The strength of the association between different viral agents and SLE is variable. Epstein-Barr virus (EBV), parvovirus B19 (B19V), and human endogenous retroviruses (HERVs) are involved in SLE pathogenesis, whereas other viruses such as Cytomegalovirus (CMV) probably play a less prominent role. However, the mechanisms of viral-host interactions and the impact of viruses on disease course have yet to be elucidated. In addition to classical mechanisms of viral-triggered autoimmunity, such as molecular mimicry and epitope spreading, there has been a growing appreciation of the role of direct activation of innate response by viral nucleic acids and epigenetic modulation of interferon-related immune response. The latter is especially important for HERVs, which may represent the molecular link between environmental triggers and critical immune genes. Virus-specific proteins modulating interaction with the host immune system have been characterized especially for Epstein-Barr virus and explain immune evasion, persistent infection and self-reactive B-cell "immortalization". Knowledge has also been expanding on key viral proteins of B19-V and CMV and their possible association with specific phenotypes such as antiphospholipid syndrome. This progress may pave the way to new therapeutic perspectives, including the use of known or new antiviral drugs, postviral immune response modulation and innate immunity inhibition. We herein describe the state-of-the-art knowledge on the role of viral infections in SLE, with a focus on their mechanisms of action and potential therapeutic targets.

Antibodies to an Epstein Barr Virus protein that cross-react with dsDNA have pathogenic potential

Pathogens such as the Epstein Barr virus (EBV) have long been implicated in the etiology of systemic lupus erythematosus (SLE). The Epstein Barr virus nuclear antigen I (EBNA-1) has been shown to play a role in the development of anti-nuclear antibodies characteristic of SLE. One mechanism by which EBV may play a role in SLE is molecular mimicry. We previously generated two monoclonal antibodies (mAbs) to EBNA-1 and demonstrated that they cross-react with double-stranded DNA (dsDNA). In the present study, we demonstrate that these mAbs have pathogenic potential. We show that they can bind to isolated rat glomeruli and that binding can be greatly diminished by pretreatment of glomeruli with DNase I, suggesting that these mAbs bind dsDNA in the kidney. We also demonstrate that these antibodies can deposit in the kidney when injected into mice and can induce proteinuria and elicit histopathological alterations consistent with glomerulonephritis. Finally, we show that these antibodies can cross-react with laminin and collagen IV in the extracellular matrix suggesting that direct binding to the glomerular basement membrane or mesangial matrix may also contribute to the antibody deposition in the kidney. In summary, our results indicate that EBNA-1 can elicit antibodies that cross-react with dsDNA, that can deposit in the kidney, and induce kidney damage. These results are significant because they support the role of a viral protein in SLE and lupus nephritis.

Contribution of viral infection to risk for cancer in systemic lupus erythematosus and multiple sclerosis

Patients with autoimmune disorders (AD) have altered cancer risks compared to the general population. Systemic lupus erythematosus and multiple sclerosis lead to a heightened risk for hematological malignancies and decreased risk for breast, ovarian, and prostate malignancies. Often patients with autoimmune disease have dysregulated antiviral immune responses, including against oncogenic viruses. To uncover the relationship between viral incidence and cancer risk in the context of autoimmune disease, we extracted electronic health records (EHR) from Vanderbilt University. ICD-9/10 codes and laboratory values were collected for hematological, lung, anal-vaginal, thyroid, hepatobiliary, bladder, prostate, and breast cancers; and viruses including Epstein Barr virus (EBV), Human papilloma virus (HPV), and Hepatitis A/B/C (Hep). Only viral infections that led to a physician visit or laboratory test were entered into the EMR; therefore, only clinically relevant cases were noted and considered positive in this study. The relationship between virus infection and cancer in an SLE cohort (SLE-cases n = 2,313, and SLE-controls n = 5,702) and an MS cohort (MS-case n = 7,277, MS-control n = 7,277) was examined by multilinear logistic regression. Viral infection was strongly associated with increased risk for cancer overall. SLE and MS patients were more susceptible to all viral infections. MS patients trended toward increased risk for cancers overall, while decreased risk for hormone-based cancers in SLE patients non-significantly reduced their risk for overall cancer. Both SLE and MS patients had increased clinically relevant EBV infection, which was associated with risk for hematological cancers. Preventing viral infections by vaccination may be especially helpful in controlling risk for cancer in SLE and MS patients.

Epstein-Barr Virus and Systemic Autoimmune Diseases

Epstein-Barr Virus (EBV) is an extremely successful human herpes virus, which infects essentially all human beings at some time during their life span. EBV infection and the associated immune response results in production of antibodies (seroconversion), which occurs mainly during the first years of life, but may also happen during adolescence or later in life. Infection of adolescents can result in infectious mononucleosis, an acute serious condition characterized by massive lymphocytosis. Transmission of EBV mainly occurs through saliva but can rarely be spread through semen or blood, e.g. through organ transplantations and blood transfusions. EBV transmission through oral secretions results in infection of epithelial cells of the oropharynx. From the epithelial cells EBV can infect B cells, which are the major reservoir for the virus, but other cell types may also become infected. As a result, EBV can shuttle between different cell types, mainly B cells and epithelial cells. Moreover, since the virus can switch between a latent and a lytic life cycle, EBV has the ability to cause chronic relapsing/reactivating infections. Chronic or recurrent EBV infection of epithelial cells has been linked to systemic lupus erythematosus and Sjögren’s syndrome, whereas chronic/recurrent infection of B cells has been associated with rheumatoid arthritis, multiple sclerosis and other diseases. Accordingly, since EBV can shuttle between epithelial cells and B cells, the systemic autoimmune diseases often occur as overlapping syndromes with symptoms and characteristic autoantibodies (e.g. antinuclear antibodies and rheumatoid factors) reflecting epithelial and/or B cell infection.

Dermatomyositis Developed After Exposure to Epstein-Barr Virus Infection and Antibiotics Use

Dermatomyositis is an inflammatory disorder involving muscle and skin. Similar to many other autoimmune diseases, environmental factors appear to trigger the onset of disease in some cases. Many drugs have been reported to be associated with dermatomyositis, and rarely infections have been described as potential triggering agents. Here we are describing a case of dermatomyositis that developed after doxycycline and levofloxacin use, who also had recent Epstein-Barr virus infection. Dermatomyositis associated with doxycycline or levofloxacin use has not yet been described in the literature, while reports of dermatomyositis after Epstein-Barr virus infection have been rare and limited to juvenile dermatomyositis or in association with cancer. It is important for clinicians to be aware of this rare association so that the diagnosis and treatment can be exercised promptly.

Self-reactive and polyreactive B cells are generated and selected in the germinal center during γ-herpesvirus infection

Immune responses against certain viruses are accompanied by auto-antibody production although the origin of these infection-associated auto-antibodies is unclear. Here, we report that murine γ-herpesvirus 68 (MHV68)-induced auto-antibodies are derived from polyreactive B cells in the germinal center (GC) through the activity of short-lived plasmablasts. The analysis of recombinant antibodies from MHV68-infected mice revealed that about 40% of IgG+ GC B cells were self-reactive, with about half of them being polyreactive. On the other hand, virion-reactive clones accounted for only a minor proportion of IgG+ GC B cells, half of which also reacted with self-antigens. The self-reactivity of most polyreactive clones was dependent on somatic hypermutation (SHM), but this was dispensable for the reactivity of virus mono-specific clones. Furthermore, both virus-mono-specific and polyreactive clones were selected to differentiate to B220lo CD138+ plasma cells (PCs). However, the representation of GC-derived polyreactive clones was reduced and that of virus-mono-specific clones was markedly increased in terminally differentiated PCs as compared to transient plasmablasts. Collectively, our findings demonstrate that, during acute MHV68 infection, self-reactive B cells are generated through SHM and selected for further differentiation to short-lived plasmablasts but not terminally differentiated PCs.

An Epigenetics-Based Hypothesis of Autoantigen Development in Systemic Lupus Erythematosus

Currently, we have a limited understanding of mechanisms leading to systemic lupus erythematosus, but we know that genetics, environmental factors, and epigenetics contribute to the disease. One common aspect of the various environmental triggers is that they can cause cellular stress. When extraordinary stress occurs, such as viral activation, a cell's response can include increased nucleolar volume and activity to produce more machinery (e.g., ribosomes) to help the cell recover. However, nucleolar expansion can disrupt the epigenetic control in neighboring heterochromatin that comprises the nucleolar shell. This disruption can open underlying vulnerabilities that provoke an autoimmune reaction. Here, we review the "X chromosome-nucleolus nexus" hypothesis, which explains how nucleolar stress can disrupt epigenetically silenced chromatin, especially the neighboring inactive X chromosome (aka the nucleolar satellite). Chromatin disruption can lead to the expression of sequestered DNA, such as Alu elements and fully functional LINE-1 reverse transcriptase genes. In addition, Alu transcripts can disrupt the nucleolar structural integrity, leading to nucleolar disintegration. Such disintegration can leave nucleolar components and products in autoantigenic forms, such as abnormal conformations or incomplete macromolecular assemblies. Recent research on DNA sensing pathways can now be incorporated into the hypothesis to provide further details explaining how autoantibodies to endogenous nucleic acids arise.

The study of factors associated with pregnancy outcomes in patients with systemic lupus erythematosus

OBJECTIVES

Systemic lupus erythematosus (SLE) is an autoimmune disease that can lead to unfavorable pregnancy complications in women. This study aimed to evaluate the factors associated with pregnancy outcomes in patients with SLE.

RESULTS

Fifty-nine pregnant women with SLE (121 pregnancies) participated in this retrospective cohort study. The mean age of the patients was 33.74 ± 3.80 years (range 21 to 48 years). Fetal loss occurred in 43.8% of pregnancies. The most common laboratory findings in SLE patients were antinuclear antibody (81.4%) and anti-ds DNA positivity (54.2%). High levels of C-reactive protein (CRP) during pregnancy, renal involvement, anti-double-stranded DNA positivity, anti-phospholipid antibody (APA) positivity and younger age at disease onset were significantly correlated with unfavourable pregnancy outcomes. A significant difference was observed between duration of SLE and low birth weight (P = 0.003), pre-eclampsia (P = 0.012) and still birth (P = 0.036). High CRP, APA positivity, anti-dsDNA positivity and kidney involvement were predictors of adverse pregnancy outcomes in SLE patients. Renal involvement increased risk of pregnancy with complication 8.5 times (OR = 8.5, 95% CI 1.396-63.373, P = 0.017). Antiphospholipid syndrome (APS) also was associated with an odds ratio of 5.18 (95% CI 1.681-13.647, P = 0.001).

A promiscuous inflammasome sparks replication of a common tumor virus

Viruses activate inflammasomes but then subvert resulting inflammatory responses to avoid elimination. We asked whether viruses could instead use such activated or primed inflammasomes to directly aid their propagation and spread. Since herpesviruses are experts at coopting cellular functions, we investigated whether Epstein-Barr virus (EBV), an oncoherpesvirus, exploits inflammasomes to activate its replicative or lytic phase. Indeed, our experiments reveal that EBV exploits several inflammasome sensors to actually activate its replicative phase from quiescence/latency. In particular, TXNIP, a key inflammasome intermediary, causes assembly of the NLRP3 inflammasome, resulting in caspase-1-mediated depletion of the heterochromatin-inducing epigenetic repressor KAP1/TRIM28 in a subpopulation of cells. As a result, only TXNIPhiKAP1lo cells, that is, in a primed/prolytic state, turn expression of the replication/lytic/reactivation switch protein on to enter the replicative phase. Our findings 1) demonstrate that EBV dovetails its escape strategy to a key cellular danger-sensing mechanism, 2) indicate that transcription may be regulated by KAP1 abundance aside from canonical regulation through its posttranslational modification, 3) mechanistically link diabetes, which frequently activates the NLRP3 inflammasome, to deregulation of a tumor virus, and 4) demonstrate that B lymphocytes from NOMID (neonatal onset multisystem inflammatory disease) patients who have NLRP3 mutations and suffer from hyperactive innate responses are defective in controlling a herpesvirus.

B Cell-Intrinsic SHP1 Expression Promotes the Gammaherpesvirus-Driven Germinal Center Response and the Establishment of Chronic Infection

Gammaherpesviruses are ubiquitous pathogens that establish lifelong infections in the majority of adults worldwide. Chronic gammaherpesvirus infection has been implicated in both lymphomagenesis and, somewhat controversially, autoimmune disease development. Pathogenesis is largely associated with the unique ability of gammaherpesviruses to usurp B cell differentiation, specifically, the germinal center response, to establish long-term latency in memory B cells. The host tyrosine phosphatase SHP1 is known as a brake on immune cell activation and is downregulated in several gammaherpesvirus-driven malignancies. However, here we demonstrate that B cell- but not T cell-intrinsic SHP1 expression supports the gammaherpesvirus-driven germinal center response and the establishment of viral latency. Furthermore, B cell-intrinsic SHP1 deficiency cooperated with gammaherpesvirus infection to increase the levels of double-stranded DNA-reactive antibodies at the peak of viral latency. Thus, in spite of decreased SHP1 levels in gammaherpesvirus-driven B cell lymphomas, B cell-intrinsic SHP1 expression plays a proviral role during the establishment of chronic infection, suggesting that the gammaherpesvirus-SHP1 interaction is more nuanced and is modified by the stage of infection and pathogenesis.IMPORTANCE Gammaherpesviruses establish lifelong infection in a majority of adults worldwide and are associated with a number of malignancies, including B cell lymphomas. These viruses infect naive B cells and manipulate B cell differentiation to achieve a lifelong infection of memory B cells. The germinal center stage of B cell differentiation is important as both an amplifier of the viral latent reservoir and the target of malignant transformation. In this study, we demonstrate that expression of tyrosine phosphatase SHP1, a negative regulator that normally limits the activation and proliferation of hematopoietic cells, enhances the gammaherpesvirus-driven germinal center response and the establishment of chronic infection. The results of this study uncover an intriguing beneficial interaction between gammaherpesviruses that are presumed to profit from B cell activation and a cellular phosphatase that is traditionally perceived to be a negative regulator of the same processes.

Viruses and Autoimmunity: A Review on the Potential Interaction and Molecular Mechanisms

For a long time, viruses have been shown to modify the clinical picture of several autoimmune diseases, including type 1 diabetes (T1D), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjögren’s syndrome (SS), herpetic stromal keratitis (HSK), celiac disease (CD), and multiple sclerosis (MS). Best examples of viral infections that have been proposed to modulate the induction and development of autoimmune diseases are the infections with enteric viruses such as Coxsackie B virus (CVB) and rotavirus, as well as influenza A viruses (IAV), and herpesviruses. Other viruses that have been studied in this context include, measles, mumps, and rubella. Epidemiological studies in humans and experimental studies in animal have shown that viral infections can induce or protect from autoimmunopathologies depending on several factors including genetic background, host-elicited immune responses, type of virus strain, viral load, and the onset time of infection. Still, data delineating the clear mechanistic interaction between the virus and the immune system to induce autoreactivity are scarce. Available data indicate that viral-induced autoimmunity can be activated through multiple mechanisms including molecular mimicry, epitope spreading, bystander activation, and immortalization of infected B cells. Contrarily, the protective effects can be achieved via regulatory immune responses which lead to the suppression of autoimmune phenomena. Therefore, a better understanding of the immune-related molecular processes in virus-induced autoimmunity is warranted. Here we provide an overview of the current understanding of viral-induced autoimmunity and the mechanisms that are associated with this phenomenon.

EBNA1 IgM-Based Discrimination Between Rheumatoid Arthritis Patients, Systemic Lupus Erythematosus Patients and Healthy Controls

Epstein-Barr Virus (EBV) has been associated with development of rheumatic connective tissue diseases like rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in genetically susceptible individuals. Diagnosis of RA and SLE relies on clinical criteria in combination with the presence of characteristic autoantibodies. In addition, antibodies to several EBV antigens have been shown to be elevated in patients with these diseases compared to healthy controls (HC). Here, we elaborated improved enzyme-linked immunosorbent assays for antibodies (IgM, IgA, IgG) to the EBV proteins Epstein-Barr Virus nuclear antigen (EBNA)1 and early antigen diffuse (EAD) in order to determine their potential diagnostic role. We showed that especially EBNA1 IgM distinguished RA from SLE and HCs and also distinguished SLE from HCs. EBNA1 IgA was almost as effective in differentiating RA from SLE and HC, while EAD IgG and IgA were able to discern SLE patients from RA patients and HCs. Collectively, these findings illustrate the potential diagnostic use of antibodies to EBV proteins to diagnose RA and to differentiate SLE from RA.