Epstein-Barr virus-associated infectious mononucleosis and risk of systemic lupus erythematosus

First-degree relatives of patients with systemic lupus erythematosus: Autoreactivity but not autoimmunity?

BACKGROUND

Systemic lupus erythematosus (SLE) is a disorder with a complex immunopathogenesis. It is well known that the disease begins with immunological alterations and autoantibody appearance in the serum years before clinical onset. As SLE has a strong tendency to familial aggregation, first-degree relatives (FDRs) constitute a group at elevated risk. The current understanding is that external risk factors trigger underlying immune dysregulations, leading to overt disease in those with elevated genetic risk.

OBJECTIVE

This cross-sectional study investigates the degree to which clinical features, external risk factors, and immunological profiles differ in SLE FDRs from healthy individuals and SLE patientts.

METHODS

Three groups were studied: Lupus patient FDRs (n = 56), healthy controls (n = 20), and SLE patients (n = 20). FDRs and healthy participants completed a detailed clinical questionnaire that included questions regarding smoking and estrogen drug history. All participants were tested for the presence of the following antinuclear autoantibodies (ANAs) against: nRNP/Sm, Sm, Ro60, Ro-52, La, Scl-70, PM-Scl, PM- Scl, Jo-1, CENP B, PCNA, dsDNA, nucleosomes, histones, RibP, AMA M2, DFS70, and eight soluble cytokines, including transforming growth factor-β (TGF-β), vitamin D levels, and antibodies against Epstein-Barr virus (EBV).

RESULTS

Compared with the healthy controls, FDRs had higher titers of ANA, more specific staining immunofluorescent patterns, and more autoantibody specificities. Furthermore, FDRs differed significantly in their TGF-β levels from the other two groups. In FDRs, some clinical features (hair loss, skin, and oral ulcer-like lesions) were associated with higher ANA titers and some (oral ulcer-like lesions) with the anti-Ro60-specific antibody. Interestingly, there was an association between ANA titers and levels of antibodies against EBV only in the FDR group.

CONCLUSION

First-degree relatives display unique clinical and immunological profiles, placing them between healthy individuals and SLE patients, with a balance between compensated immune dysregulation and disease-developing potential. A possible association between ANA titer and the number of clinical complaints is observed, which needs to be confirmed in more extensive studies.

Systemic Lupus Erythematosus Risk: The Role of Environmental Factors

Systemic lupus erythematosus (SLE) is a complex, chronic autoimmune disease. The etiology of SLE is multifactorial and includes potential environmental triggers, which may occur sequentially (the "multi-hit" hypothesis). This review focuses on SLE risk potentially associated with environmental factors including infections, the microbiome, diet, respirable exposures (eg, crystalline silica, smoking, air pollution), organic pollutants, heavy metals, and ultraviolet radiation.

Understanding the Concept of Pre-Clinical Autoimmunity: Prediction and Prevention of Systemic Lupus Erythematosus: Identifying Risk Factors and Developing Strategies Against Disease Development

There is growing evidence that preceding the diagnosis or classification of systemic lupus erythematosus (SLE), patients undergo a preclinical phase of disease where markers of inflammation and autoimmunity are already present. Not surprisingly then, even though SLE management has improved over the years, many patients will already have irreversible disease-related organ damage by time they have been diagnosed with SLE. By gaining a greater understanding of the pathogenesis of preclinical SLE, we can potentially identify patients earlier in the disease course who are at-risk of transitioning to full-blown SLE and implement preventative strategies. In this review, we discuss the current state of knowledge of SLE preclinical pathogenesis and propose a screening and preventative strategy that involves the use of promising biomarkers of early disease, modification of lifestyle and environmental risk factors, and initiation of preventative therapies, as examined in other autoimmune diseases such as rheumatoid arthritis and type 1 diabetes.

The role of environmental exposures and gene-environment interactions in the etiology of systemic lupus erythematous

Systemic lupus erythematosus (SLE) is a complex, chronic autoimmune disease, whose etiology includes both genetic and environmental factors. Individual genetic risk factors likely only account for about one-third of observed heritability among individuals with a family history of SLE. A large portion of the remaining risk may be attributable to environmental exposures and gene-environment interactions. This review focuses on SLE risk associated with environmental factors, ranging from chemical and physical environmental exposures to lifestyle behaviors, with the weight of evidence supporting positive associations between SLE and occupational exposure to crystalline silica, current smoking, and exogenous estrogens (e.g., oral contraceptives and postmenopausal hormones). Other risk factors may include lifestyle behaviors (e.g., dietary intake and sleep) and other exposures (e.g., ultraviolet [UV] radiation, air pollution, solvents, pesticides, vaccines and medications, and infections). Alcohol use may be associated with decreased SLE risk. We also describe the more limited body of knowledge on gene-environment interactions and SLE risk, including IL-10, ESR1, IL-33, ITGAM, and NAT2 and observed interactions with smoking, UV exposure, and alcohol. Understanding genetic and environmental risk factors for SLE, and how they may interact, can help to elucidate SLE pathogenesis and its clinical heterogeneity. Ultimately, this knowledge may facilitate the development of preventive interventions that address modifiable risk factors in susceptible individuals and vulnerable populations.

Extracellular Vesicles in Epstein-Barr Virus Pathogenesis

Purpose of review

Epstein-Barr virus (EBV) is a known determinant for numerous malignancies and may contribute to autoimmune diseases. The underlining mechanisms behind EBV pathologies is not completely understood. Recently, extracellular vesicles (EVs) released from infected cells have been found to produce profound effects on cellular microenvironments. Therefore, in this review we sought to critically evaluate the roles of EVs in EBV pathogenesis and assess their potential therapeutic and diagnostic utility.

Recent findings

EBV-altered EVs are capable of activating signaling cascades and phenotypic changes in recipient cells through the transfer of viral proteins and RNAs. Moreover, several EV-associated microRNAs have encouraging prognostic or diagnostic potential in EBV-associated cancers.

Summary

Current evidence suggests that EBV-modified EVs affect viral pathogenesis and cancer progression. However, further research is needed to investigate the direct role of both viral and host products on recipient cells and the mechanisms driving viral protein and RNA EV packaging and content modification.

The study of interactions between genome and exposome in the development of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic inflammatory autoimmune disease characterized by a broad spectrum of clinical and serological manifestations. This may reflect a complex and multifactorial etiology involving several identified genetic and environmental factors, though not explaining the full risk of SLE. Established SLE risk genotypes are either very rare or with modest effect sizes and twin studies indicate that other factors besides genetics must be operative in SLE etiology. The exposome comprises the cumulative environmental influences on an individual and associated biological responses through the lifespan. It has been demonstrated that exposure to silica, smoking and exogenous hormones candidate as environmental risk factors in SLE, while alcohol consumption seems to be protective. Very few studies have investigated potential gene-environment interactions to determine if some of the unexplained SLE risk is attributable hereto. Even less have focused on interactions between specific risk genotypes and environmental exposures relevant to SLE pathogenesis. Cohort and case-control studies may provide data to suggest such biological interactions and various statistical measures of interaction can indicate the magnitude of such. However, such studies do often have very large sample-size requirements and we suggest that the rarity of SLE to some extent can be compensated by increasing the ratio of controls. This review summarizes the current body of knowledge on gene-environment interactions in SLE. We argue for the prioritization of studies that comprise the increasing details available of the genome and exposome relevant to SLE as they have the potential to disclose new aspects of SLE pathogenesis including phenotype heterogeneity.

Whole-genome association study of antibody response to Epstein-Barr virus in an African population: a pilot

Epstein Barr virus (EBV) infects 95% of the global population and is associated with up to 2% of cancers globally. Immunoglobulin G (IgG) antibody levels to EBV have been shown to be heritable and associated with developing malignancies. We, therefore, performed a pilot genome-wide association analysis of anti-EBV IgG traits in an African population, using a combined approach including array genotyping, whole-genome sequencing and imputation to a panel with African sequence data. In 1562 Ugandans, we identify a variant in human leukocyte antigen (HLA)-DQA1, rs9272371 (p = 2.6 × 10-17) associated with anti-EBV nuclear antigen-1 responses. Trans-ancestry meta-analysis and fine-mapping with European-ancestry individuals suggest the presence of distinct HLA class II variants driving associations in Uganda. In addition, we identify four putative, novel, very rare African-specific loci with preliminary evidence for association with anti-viral capsid antigen IgG responses which will require replication for validation. These findings reinforce the need for the expansion of such studies in African populations with relevant datasets to capture genetic diversity.

Family history of systemic lupus erythematosus and risk of autoimmune disease: Nationwide Cohort Study in Denmark 1977-2013

Objective

To provide population-based estimates of relative risk of SLE and other autoimmune diseases (ADs) in relatives of SLE patients.

Methods

A cohort of 5 237 319 Danish residents identified through the Civil Registration System was coupled to their relatives through the parental link and followed for SLE and other ADs between 1977 and 2013 through linkage to the National Patient Register. Twin zygosity was established through the Danish Twin Registry. Hazard ratios (HRs) with 95% CIs were calculated using Cox proportional hazards regression analyses.

Results

During 117.5 million person-years of follow-up, 3612 persons were hospitalized with SLE. HRs of SLE were high among first-degree (HR = 10.3; 95% CI: 8.25, 12.9; n = 80) and second- or third-degree relatives of SLE patients (HR = 3.60; 95% CI: 2.20, 5.90; n = 16). HRs for any AD were elevated in first-degree (HR = 1.51; 95% CI: 1.41, 1.62; n = 785) and second- or third-degree relatives of SLE patients (HR = 1.28; 95% CI: 1.18, 1.39; n = 582). Among individuals with SLE-affected first-degree relatives, the risk was significantly increased for RA (HR = 1.64; 95% CI: 1.35, 1.99; n = 103), IBD (HR = 1.21; 95% CI: 1.02, 1.43; n = 130) and type 1 diabetes mellitus (HR = 1.23; 95% CI: 1.01, 1.48; n = 106). Risk of other ADs was significantly increased both among SLE-affected first-degree (HR = 2.08; 95% CI: 1.88, 2.31; n = 371) and second- or third-degree relatives (HR = 1.38; 95% CI: 1.23, 1.54; n = 313).

Conclusion

Family history of SLE is associated with a clearly elevated risk of SLE and, to a much lesser degree, of RA and other ADs.

Environmental exposures and the development of systemic lupus erythematosus

PURPOSE OF REVIEW

This review examines evidence relating environmental factors to the development of systemic lupus erythematosus (SLE).

RECENT FINDINGS

The strongest epidemiologic evidence exists for the associations of silica, cigarette smoking, oral contraceptives, postmenopausal hormone therapy and endometriosis, with SLE incidence. Recent studies have also provided robust evidence of the association between alcohol consumption and decreased SLE risk. There are preliminary, conflicting or unsubstantiated data that other factors, including air pollution, ultraviolet light, infections, vaccinations, solvents, pesticides and heavy metals such as mercury, are related to SLE risk. Biologic mechanisms linking environmental exposures and SLE risk include increased oxidative stress, systemic inflammation and inflammatory cytokine upregulation, and hormonal triggers, as well as epigenetic modifications resulting from exposure that could lead to SLE.

SUMMARY

Identifying the environmental risk factors related to risk of SLE is essential as it will lead to increased understanding of pathogenesis of this complex disease and will also make risk factor modification possible for those at increased risk.

Understanding the role of environmental factors in the development of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystem disease with a complex etiology. Its risk is higher among women, racial and ethnic minorities, and individuals with a family history of SLE or related autoimmune diseases. It is believed that genetic factors interact with environmental exposures throughout the lifespan to influence susceptibility to developing SLE. The strongest epidemiologic evidence exists for increased risk of SLE associated with exposure to crystalline silica, current cigarette smoking, use of oral contraceptives, and postmenopausal hormone replacement therapy, while there is an inverse association with alcohol use. Emerging research results suggest possible associations of SLE risk with exposure to solvents, residential and agricultural pesticides, heavy metals, and air pollution. Ultraviolet light, certain infections, and vaccinations have also been hypothesized to be related to SLE risk. Mechanisms linking environmental exposures and SLE include epigenetic modifications resulting from exposures, increased oxidative stress, systemic inflammation and inflammatory cytokine upregulation, and hormonal effects. Research needs to include new studies of environmental risk factors for SLE in general, with a focus on lifetime exposure assessment. In addition, studies in susceptible subgroups, such as family members, studies based on genetic risk profiles, and studies in individuals with evidence of pre-clinical autoimmunity based on the detection of specific auto-antibodies are also required. Understanding the role of environmental exposures in the development of SLE may help identify modifiable risk factors and potential etiological mechanisms.

Correlation between Epstein-Barr Virus Infection and Disease Activity of Systemic Lupus Erythematosus: a Cross-Sectional Study

Background:

Systemic lupus erythematosus (SLE) is an autoimmune disease for whose pathogenesis viral infections are important. The Epstein-Barr virus (EBV) is the main infectious etiological agent. This study aimed to quantitative evaluation of EBV in SLE patients.

Materials and Methods:

In this cross-sectional study, 40 patients with SLE diagnosed based on American College of Rheumatology criteria were selected using purposive sampling. All were included in the study after obtaining informed consent for participation. Whole blood samples were taken and buffy coat preparations were isolated to determine viral load using the real-time polymerase chain reaction method and assessment with the SLE disease activity index (SLE-DAI).

Results:

From a total of 40 patients, 37 cases (92.5%) were women. The EBV test was positive in 67.5% and mean viral load was 5396 ± 1891.9 copy/ml. Twenty of forty patients had active and 50% inactive disease, mean EBV viral loads being 6798 and 28.25 copy/ml, respectively (P-value = 0.003). In terms of the severity of disease activity, 17.5 % of female patients had mild to moderate activity, whilst 32.5% of them had severe activity, with respective viral loads of 5,803.3 and 29.73 copy/ml (P-value = 0.003).

Conclusion:

The Epstein-Barr viral load in SLE patients with active disease was found to be markedly higher than in inactive cases. Thus, EBV may have an important role in the pathogenesis and activity of SLE.

Modulation of Immunoregulatory Properties of Mesenchymal Stromal Cells by Toll-Like Receptors: Potential Applications on GVHD

In the last decade, the immunomodulatory properties of mesenchymal stromal cells (MSCs) have attracted a lot of attention, due to their potential applicability in the treatment of graft-versus-host disease (GVHD), a condition frequently associated with opportunistic infections. The present review addresses how Pathogen-Associated Molecular Patterns (PAMPS) modulate the immunosuppressive phenotype of human MSCs by signaling through Toll-like receptors (TLRs). Overall, we observed that regardless of the source tissue, human MSCs express TLR2, TLR3, TLR4, and TLR9. Stimulation of distinct TLRs on MSCs elicits distinct inflammatory signaling pathways, differentially influencing the expression of inflammatory factors and the ability of MSCs to suppress the proliferation of immune system cells. The capacity to enhance the immunosuppressive phenotype of MSCs through TLRs stimulation might be properly elucidated in order to improve the MSC-based immunotherapy against GVHD.

EBV and Autoimmunity

Although a role of EBV in autoimmunity is biologically plausible and evidence of altered immune responses to EBV is abundant in several autoimmune diseases, inference on causality requires the determination that disease risk is higher in individuals infected with EBV than in those uninfected and that in the latter it increases following EBV infection. This determination has so far been possible only for multiple sclerosis (MS) and, to some extent, for systemic lupus erythematosus (SLE), whereas evidence is either lacking or not supportive for other autoimmune conditions. In this chapter, we present the main epidemiological findings that justify the conclusion that EBV is a component cause of MS and SLE and possible mechanisms underlying these effects.

Epstein-Barr virus in systemic lupus erythematosus, rheumatoid arthritis and multiple sclerosis—association and causation

Epidemiological data suggest that the Epstein-Barr virus (EBV) is associated with several autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis and multiple sclerosis. However, it is not clear whether EBV plays a role in the pathogenesis of these diseases, and if so, by which mechanisms the virus may contribute. In this review, we discuss possible viral and immunological mechanisms that might explain associations between EBV and autoimmune diseases and whether these associations represent causes or effects of inflammation and autoimmunity.

Serum concentration of immunoglobulin G-type antibodies against the whole Epstein-Barr nuclear antigen 1 and its aa35-58 or aa398-404 fragments in the sera of patients with systemic lupus erythematosus and multiple sclerosis

Several studies suggest that infection by Epstein-Barr virus (EBV) might be one of the environmental factors which facilitates the development of autoimmune disorders in genetically susceptible individuals. Recent data indicate that high anti-Epstein-Barr nuclear antigen 1 (EBNA)-1 immunoglobulin (Ig)G titre is a strong risk factor for multiple sclerosis (MS) in patients both with and without the main genetic predisposing trait, human leucocyte antigen (HLA)-DRB1*15:01. Because no similar studies have been published in systemic lupus erythematosus (SLE) patients, we determined the HLA-DRB1*15:01 carrier state and the serum titres against the whole EBNA-1 and its small fragments aa35-58 and aa398-404 in 301 SLE patients, 135 MS patients and in 345 healthy controls. The carrier state of the HLA-DRB1*15:01 allele was deduced from genotyping of a tagSNP (rs3135388) by applying a Taqman-based assay. The serum concentrations of antibodies to EBNA-1 and its aa35-58 or aa398-404 fragments were determined using a commercial assay (ETI-EBNA-G) and home-made enzyme-linked immunosorbent assays, respectively. The serum concentration of anti-EBNA-1 antibodies was significantly (P < 0·001) higher both in MS and SLE patients than in controls. Similar significant differences were found both in HLA-DRB1*15:01 carriers and non-carriers. Furthermore, titres of antibodies against the aa35-58 EBNA-1 fragment were elevated both in MS and SLE patients. By contrast, the levels of aa398-404 EBNA-1 antibodies were elevated significantly only in the SLE patients. These findings indicate that high anti-EBNA-1 IgG titres are HLA-DRB1*15:01-independent risk factors not only for MS, but also for SLE, while high antibody titres against the aa398-404 fragment are characteristic for SLE.

Epstein–Barr virus and autoimmunity: the role of a latent viral infection in multiple sclerosis and systemic lupus erythematosus pathogenesis

Multiple sclerosis (MS) and systemic lupus erythematosus (SLE) are both chronic autoimmune diseases with unknown etiology. To date, EBV is the most closely implicated infectious agent to be associated with both MS and SLE. Epidemiological findings show a strong correlation between EBV infection and the risk of developing these diseases. The type and magnitude of both EBV-specific antibodies and T-cell responses produced by MS or SLE patients are dysregulated when compared with healthy cohorts. Despite all these findings, it is still not clear if and how EBV triggers autoimmunity. EBV infects and establishes latency mainly in B cells, but it can also infect other cell types and indirectly influence the activation status of the immune system by stimulating the production of proinflammatory mediators. This could play a role in both MS and SLE pathogenesis. In this review we will summarize recent literature that links EBV infection to SLE and MS, and discuss possible new mechanisms that explain how EBV drives autoimmunity.

Lupus and Epstein-Barr

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) is a heterogeneous human disease influenced by a complex interplay of necessary, but not individually sufficient, factors. Although many genetic and environmental factors are associated with SLE, this review will focus on the evolving evidence for key Epstein-Barr virus (EBV)-specific roles in SLE, focusing on new experimental studies published during 2009, 2010, and 2011.

RECENT FINDINGS

SLE patients have a dysregulated immune response against EBV. EBV antigens exhibit structural molecular mimicry with common SLE antigens and functional molecular mimicry with critical immune-regulatory components. SLE patients, from a number of unique geographic regions, are shown to have higher rates of EBV seroconversion, especially against early EBV antigens, suggesting frequent viral reactivation. SLE patients also have increased EBV viral loads and impaired EBV-specific CD8 cytotoxic T cells, with impaired cytokine responses to EBV in lupus patients. Irregular cytokine production in plasmacytoid dendritic cells and CD69 CD4 T cells after stimulation with EBV has also been demonstrated.

SUMMARY

Recent advances demonstrate SLE-specific serologic responses, gene expression, viral load, T-cell responses, humoral fine specificity, and molecular mimicry with EBV, further supporting potential roles for EBV in lupus etiology and pathogenesis.

Immune modulation during latent herpesvirus infection

Nearly all human beings, by the time they reach adolescence, are infected with multiple herpesviruses. At any given time, this family of viruses accounts for 35-40 billion human infections worldwide, making herpesviruses among the most prevalent pathogens known to exist. Compared to most other viruses, herpesviruses are also unique in that infection lasts the life of the host. Remarkably, despite their prevalence and persistence, little is known about how these viruses interact with their hosts, especially during the clinically asymptomatic phase of infection referred to as latency. This review explores data in human and animal systems that reveal the ability of latent herpesviruses to modulate the immune response to self and environmental antigens. From the perspective of the host, there are both potentially detrimental and surprisingly beneficial effects of this lifelong interaction. The realization that latent herpesvirus infection modulates immune responses in asymptomatic hosts forces us to reconsider what constitutes a 'normal' immune system in a healthy individual.

The role of the Epstein-Barr virus in the pathogenesis of some autoimmune disorders - Similarities and differences

After a brief summary on the properties of the Epstein-Barr virus (EBV), the course and latency stages of the infection, the characteristics of infectious mononucleosis (IM), and other disorders caused by this virus, as well as the course of the serological responses to EBV, the current paper focuses on the role of EBV in two autoimmune disorders: multiple sclerosis (MS), and systemic lupus erythematosus (SLE). Diverse evidence suggests that infection by EBV during late childhood or young adulthood may have a role in the pathogenesis of MS. These include the similarity between the geographical distribution of IMand MS, the high risk of contracting MS by individuals who have recovered from IM, the elevation of the titers of IgG antibodies against EBV nuclear antigens occurring years before the initial manifestations of MS, and the extremely rare occurrence of MS in individuals seronegative for EBV. However, the data on the mechanism underlying the relationship between EBV and MS are controversial. Moreover, many observations indicate that EBV contributes also to the pathomechanism of SLE. However, this contribution differs from the relationship between EBV and MS, as shown by the lack of any increase in the risk of SLE after IM. In SLE, EBV serology is quantitatively and qualitatively different from the normal response - that is, EBV viral load is higher and a strong cross-reaction can be detected between certain EBV antigens and autoantigens of pathological importance. These observations, along with the findings pointing to a possible role of EBV in rheumatoid arthritis and myasthenia gravis indicate that infection by EBV may be one of the environmental factors, which can facilitate the development of some autoimmune disorders in genetically susceptible individuals.

Prevalence of Epstein-Barr virus in tonsils and adenoids of United Arab Emirates nationals

OBJECTIVE

Given that Epstein-Barr virus (EBV) often inhabits human tonsils and adenoids, it remains to be distinctively determined its prevalence and in which cell and microenvironment the virus is present.

METHODS

To determine the prevalence of EBV in the tonsils and adenoids of the United Arab Emirates (UAE) nationals and to provide a basis for understanding the origin and biology of EBV-infected cells, the immunophenotype of all EBV-infected cells in 46 tonsils and 46 adenoids was determined by EBER in situ hybridization and immunohistochemistry with monoclonal antibodies to T cells (CD3), B cells (CD20), and epithelial cells (cytokeratin AE1/AE3), as well as immunostaining with antibodies to EBV latent membrane protein-1 (LMP-1).

RESULTS

EBV was found in 43% of tonsillectomy specimens and 15% of adenoidectomy specimens. All EBV-infected cells were found to be B lymphocytes. About 90% of the infected B cells are found in the interfollicular regions of tonsils and adenoids and the remaining 10% are found within the follicles. There is no significant association between EBV infection, age (P=0.324) and gender (P=0.442).

CONCLUSION

EBV is associated with tonsillar hypertrophy and is prevalent in 43% of our cases. EBV is only detected in B lymphocytes and we believe that B lymphocytes are sites of primary infection and latency. In situ hybridization is the gold standard for the detection of EBV in tissue.