Exhausted cytotoxic control of Epstein-Barr virus in human lupus

Type I interferon and mitochondrial dysfunction are associated with dysregulated cytotoxic CD8+ T cell responses in juvenile systemic lupus erythematosus

Juvenile systemic lupus erythematosus (JSLE) is an autoimmune condition which causes significant morbidity in children and young adults and is more severe in its presentation than adult-onset SLE. While many aspects of immune dysfunction have been studied extensively in adult-onset SLE, there is limited and contradictory evidence of how cytotoxic CD8+ T cells contribute to disease pathogenesis and studies exploring cytotoxicity in JSLE are virtually non-existent. Here, we report that CD8+ T cell cytotoxic capacity is reduced in JSLE versus healthy controls, irrespective of treatment or disease activity. Transcriptomic and serum metabolomic analysis identified that this reduction in cytotoxic CD8+ T cells in JSLE was associated with upregulated type I interferon (IFN) signalling, mitochondrial dysfunction, and metabolic disturbances when compared to controls. Greater interrogation of the influence of these pathways on altered cytotoxic CD8+ T cell function demonstrated that JSLE CD8+ T cells had enlarged mitochondria and enhanced sensitivity to IFN-α leading to selective apoptosis of effector memory (EM) CD8+ T cells, which are enriched for cytotoxic mediator-expressing cells. This process ultimately contributes to the observed reduction in CD8+ T cell cytotoxicity in JSLE, reinforcing the growing evidence that mitochondrial dysfunction is a key pathogenic factor affecting multiple immune cell populations in type I IFN-driven rheumatic diseases.

Epstein-Barr virus as a potentiator of autoimmune diseases

The Epstein-Barr virus (EBV) is epidemiologically associated with development of autoimmune diseases, including systemic lupus erythematosus, Sjögren syndrome, rheumatoid arthritis and multiple sclerosis. Although there is well-established evidence for this association, the underlying mechanistic basis remains incompletely defined. In this Review, we discuss the role of EBV infection as a potentiator of autoimmune rheumatic diseases. We review the EBV life cycle, viral transcription programmes, serological profiles and lytic reactivation. We discuss the epidemiological and mechanistic associations of EBV with systemic lupus erythematosus, Sjögren syndrome, rheumatoid arthritis and multiple sclerosis. We describe the potential mechanisms by which EBV might promote autoimmunity, including EBV nuclear antigen 1-mediated molecular mimicry of human autoantigens; EBV-mediated B cell reprogramming, including EBV nuclear antigen 2-mediated dysregulation of autoimmune susceptibility genes; EBV and host genetic factors, including the potential for autoimmunity-promoting strains of EBV; EBV immune evasion and insufficient host responses to control infection; lytic reactivation; and other mechanisms. Finally, we discuss the therapeutic implications and potential therapeutic approaches to targeting EBV for the treatment of autoimmune disease.

Hypocortisolemic ASIA: a vaccine- and chronic infection-induced syndrome behind the origin of long COVID and myalgic encephalomyelitis

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), long COVID (LC) and post-COVID-19 vaccine syndrome show similarities in their pathophysiology and clinical manifestations. These disorders are related to viral or adjuvant persistence, immunological alterations, autoimmune diseases and hormonal imbalances. A developmental model is postulated that involves the interaction between immune hyperactivation, autoimmune hypophysitis or pituitary hypophysitis, and immune depletion. This process might begin with a deficient CD4 T-cell response to viral infections in genetically predisposed individuals (HLA-DRB1), followed by an uncontrolled immune response with CD8 T-cell hyperactivation and elevated antibody production, some of which may be directed against autoantigens, which can trigger autoimmune hypophysitis or direct damage to the pituitary, resulting in decreased production of pituitary hormones, such as ACTH. As the disease progresses, prolonged exposure to viral antigens can lead to exhaustion of the immune system, exacerbating symptoms and pathology. It is suggested that these disorders could be included in the autoimmune/adjuvant-induced inflammatory syndrome (ASIA) because of their similar clinical manifestations and possible relationship to genetic factors, such as polymorphisms in the HLA-DRB1 gene. In addition, it is proposed that treatment with antivirals, corticosteroids/ginseng, antioxidants, and metabolic precursors could improve symptoms by modulating the immune response, pituitary function, inflammation and oxidative stress. Therefore, the purpose of this review is to suggest a possible autoimmune origin against the adenohypophysis and a possible improvement of symptoms after treatment with corticosteroid replacement therapy.

T cell expressions of aberrant gene signatures and Co-inhibitory receptors (Co-IRs) as predictors of renal damage and lupus disease activity

BACKGROUND

Systemic lupus erythematosus (SLE) is distinguished by an extensive range of clinical heterogeneity with unpredictable disease flares and organ damage. This research investigates the potential of aberrant signatures on T cell genes, soluble Co-IRs/ligands, and Co-IRs expression on T cells as biomarkers for lupus disease parameters.

METHODS

Comparative transcriptome profiling analysis of non-renal and end-stage renal disease (ESRD) phenotypes of SLE was performed using CD4 + and CD8 + cDNA microarrays of sorted T cells. Comparing the expression of Co-IRs on T cells and serum soluble mediators among healthy and SLE phenotypes.

RESULTS

SLE patients with ESRD were downregulated CD38, PLEK, interferon-γ, CX3CR1, FGFBP2, and SLCO4C1 transcripts on CD4 + and CD8 + T cells simultaneously and NKG7, FCRL6, GZMB/H, FcγRIII, ITGAM, Fas ligand, TBX21, LYN, granulysin, CCL4L1, CMKLR1, HLA-DRβ, KIR2DL3, and KLRD1 in CD8 T cells. Pathway enrichment and PPI network analyses revealed that the overwhelming majority of Differentially Expressed Genes (DEGs) have been affiliated with novel cytotoxic, antigen presentation, and chemokine-cell migration signature pathways. CD8 + GZMK + T cells that are varied in nature, including CD161 + Mucosal-associated invariant T (MAIT) cells and CD161- aged-associated T (Taa) cells and CD161-GZMK + GZMB + T cells might account for a higher level of GZMK in CD8 + T cells associated with ESRD. SLE patients have higher TIGIT + , PD1 + , and lower CD127 + cell percentages on CD4 + T cells, higher TIM3 + , TIGIT + , HLA-DR + cell frequency, and lower MFI expression of CD127, CD160 in CD8 T cells. Co-IRs expression in T cells was correlated with soluble PD-1, PDL-2, and TIM3 levels, as well as SLE disease activity, clinical phenotypes, and immune-therapy responses.

CONCLUSION

The signature of dysfunctional pathways defines a distinct immunity pattern in LN ESRD patients. Expression levels of Co-IRs in peripheral blood T cells and serum levels of soluble PD1/PDL-2/TIM3 can serve as biomarkers for evaluating clinical parameters and therapeutic responses.

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.

Epstein-Barr virus reactivation and disease flare of systemic lupus erythematosus

SLE affects females rather than males with a ratio of about 9:1. Owing to the high morbidity with multiple organ involvement, SLE flare-up remains a challenge for women's health. In an accumulation of the past 70 years of studies globally, EBV has been found to be strongly associated with SLE. In the past two decades, EBV reactivation has been proven as prevalent in SLE patients as well as being strongly associated with higher SLE activity and higher prevalence of SLE flare. Hence, strategies to control EBV reactivation in SLE including pharmacological (such as Tenofovir prodrugs TDF and TAF) and non-pharmacological approaches are being developed. The heterogeneity of SLE constitutes clinical challenges, suggesting a stratification of SLE into subgroups based on EBV reactivation or non-reactivation is reasonable. Future-wise, adding anti-EBV reactivation medication to current immunosuppressants for the subgroup of SLE patients with EBV reactivation could be beneficial to achieve long-term remission of SLE.

Autoimmune Responses and Therapeutic Interventions for Systemic Lupus Erythematosus: A Comprehensive Review

Systemic Lupus Erythematosus (SLE) or Lupus is a multifactorial autoimmune disease of multiorgan malfunctioning of extremely heterogeneous and unclear etiology that affects multiple organs and physiological systems. Some racial groups and women of childbearing age are more susceptible to SLE pathogenesis. Impressive progress has been made towards a better understanding of different immune components contributing to SLE pathogenesis. Recent investigations have uncovered the detailed mechanisms of inflammatory responses and organ damage. Various environmental factors, pathogens, and toxicants, including ultraviolet light, drugs, viral pathogens, gut microbiome metabolites, and sex hormones trigger the onset of SLE pathogenesis in genetically susceptible individuals and result in the disruption of immune homeostasis of cytokines, macrophages, T cells, and B cells. Diagnosis and clinical investigations of SLE remain challenging due to its clinical heterogeneity and hitherto only a few approved antimalarials, glucocorticoids, immunosuppressants, and some nonsteroidal anti-inflammatory drugs (NSAIDs) are available for treatment. However, the adverse effects of renal and neuropsychiatric lupus and late diagnosis make therapy challenging. Additionally, SLE is also linked to an increased risk of cardiovascular diseases due to inflammatory responses and the risk of infection from immunosuppressive treatment. Due to the diversity of symptoms and treatment-resistant diseases, SLE management remains a challenging issue. Nevertheless, the use of next-generation therapeutics with stem cell and gene therapy may bring better outcomes to SLE treatment in the future. This review highlights the autoimmune responses as well as potential therapeutic interventions for SLE particularly focusing on the recent therapeutic advancements and challenges.

Immunohistochemical expression of perforin in adult systemic lupus erythematosus associated macrophage activation syndrome: Clinicohematological correlation and literature review

OBJECTIVE

To study the bone marrow (BM) immunohistomorphological characteristics in adult systemic lupus erythematosus (SLE) associated macrophage activation syndrome (SLE-MAS).

MATERIALS AND METHODS

Immunohistochemical (IHC) expression of CD3, CD8, perforin (PFN), and CD163 was studied on BM trephine biopsies from 30 cytopenic adult SLE cases (male: female = 1:5, age; 24 years, range; 19-32) and compared them with ten age matched controls. Clinicopathological parameters were compared among the cases likely (L) or unlikely (U) to have MAS using probability scoring criteria. The best cut off laboratory parameters to discriminate between the two were obtained through receiver operator curve (ROC) analysis.

RESULTS

MAS occurred in 12/30 (40%) cases and was more commonly associated with prior immunosuppressive therapy (p = .07), ≥ 3 system involvement (p = .09), lower fibrinogen (p < .01), increased triglyceride (p = .002), increased BM hemophagocytosis (p = .002), and higher MAS score [185 (176-203) vs. 105 (77-119), p < .01] than MAS-U subgroup. Although PFN+CD8+ T lymphocytes significantly decreased among cases than controls (p < .05), it was comparable between MAS-L and MAS-U subgroups. Fibrinogen (< 2.4 g/L, AUC; 0.93, p < .01), hemophagocytosis score (> 1.5, AUC; 0.71, p = .03), and an MAS probability score of ≥ 164 (AUC; 1, p < .01) discriminated MAS from those without MAS.

CONCLUSION

We noted a decrease in perforin mediated CD8 + T cell cytotoxicity in SLE. Immunohistochemical demonstration of the same along with histiocytic hemophagocytosis on BM biopsy may be useful adjunct in early diagnosis and management of MAS in SLE.

Epstein-Barr virus infection as potential indicator of the occurrence and clinical presentation of systemic lupus erythematosus

Introduction

The relationship between Systemic lupus erythematosus (SLE) and Epstein-Barr virus (EBV) infection has been suggested for decades, but the underlying mechanism of the EBV influence on SLE development remains to be elucidated.

Methods

The goals of this research, which included 103 SLE patients and 99 controls, were to investigate the association of the parameters of EBV infection and SLE, to explore whether pooled demographic, clinical and EBV markers achieve a more significant effect on SLE development than each of them individually, and to evaluate EBV nuclear antigen 1 (EBNA1) and latent membrane protein 1 (LMP1) gene polymorphisms in isolates from SLE patients.

Results

Comprehensive results related to serological, molecular and sequence markers of EBV infection in SLE patients demonstrated even 24 times higher possibility of having SLE if there is the presence of anti-EBV-EA(D) (early antigen) IgG antibodies (OR=24.086 95%CI OR=2.86-216.07, p=0.004). There was the same distribution of glucocorticoids (p=0.130), antimalarials (p=0.213), and immunosuppressives (p=0.712) in anti-EBV-EA(D) IgG positive and negative SLE patients. Further, higher anti-EBV-EA(D) IgG antibodies titers were identified as independent factors associated with lymphopenia, hematological SLE manifestation (OR=1.041, 95%CI OR=1.01-1.08, p=0.025, while a higher titer of anti-CA (viral capsid antigen) IgG antibodies (OR=1.015, 95%CI OR=1.01-1.03, p=0.019) and positive RF (rheumatoid factors) (OR=4.871, 95%CI OR=1.52-15.61, p=0.008) were identified as independent factors associated with alopecia within SLE. Finally, novel data on EBV EBNA1 and LMP1 gene polymorphisms in lupus are reported.

Conclusion

The results support further investigation targeting EBV as a prognostic marker and therapeutic goal for lupus.

Hierarchical transcriptional network governing heterogeneous T cell exhaustion and its implications for immune checkpoint blockade

The fundamental principle of immune checkpoint blockade (ICB) is to protect tumor-infiltrating T cells from being exhausted. Despite the remarkable success achieved by ICB treatment, only a small group of patients benefit from it. Characterized by a hypofunctional state with the expression of multiple inhibitory receptors, exhausted T (Tex) cells are a major obstacle in improving ICB. T cell exhaustion is a progressive process which adapts to persistent antigen stimulation in chronic infections and cancers. In this review, we elucidate the heterogeneity of Tex cells and offer new insights into the hierarchical transcriptional regulation of T cell exhaustion. Factors and signaling pathways that induce and promote exhaustion are also summarized. Moreover, we review the epigenetic and metabolic alterations of Tex cells and discuss how PD-1 signaling affects the balance between T cell activation and exhaustion, aiming to provide more therapeutic targets for applications of combinational immunotherapies.

Elevated Antibody Titers to Epstein-Barr Virus and Cytomegalovirus in Patients with Drug-Induced Lupus

Systemic lupus erythematosus (SLE) is an autoimmune disease, which has been associated with Epstein-Barr virus (EBV) and Cytomegalovirus (CMV) infection. Drug-induced lupus (DIL) is a lupus-like disease caused by the intake of therapeutic drugs, which has been estimated to cause approximately 10-15% of lupus-like cases. Although SLE and DIL share common clinical symptoms, there are some fundamental differences between DIL and SLE onset. Moreover, it remains to be examined whether environmental factors, such as EBV and CMV infections, may contribute to the development of DIL. This study focused on examining the possible association between DIL and EBV and CMV infections, by examining IgG titers to EBV and CMV antigens in serum samples by enzyme-linked immunosorbent assays. Antibody titers to EBV early antigen-diffuse and CMV pp52 were found to be significantly elevated in both SLE and DIL patients compared to healthy controls, although no correlation was found for antibodies to the two virus antigens in the respective disease groups. Moreover, total IgG titers were reduced in SLE and DIL serum samples, which may reflect a general lymphocytopenia, which commonly is associated with SLE. The current findings support that EBV and CMV infections may contribute to the development of DIL and that onset of both diseases are related.

When AHR signaling pathways meet viral infections

Aryl hydrocarbon receptor (AHR) is a ligand-dependent transcriptional factor widely expressed among immune, epithelial, endothelial and stromal cells in barrier tissues. It can be activated by small molecules provided by pollutants, microorganisms, food, and metabolism. It has been demonstrated that AHR plays an important role in modulating the response to many microbial pathogens, and the abnormal expression of AHR signaling pathways may disrupt endocrine, cause immunotoxicity, and even lead to the occurrence of cancer. Most humans are infected with at least one known human cancer virus. While the initial infection with these viruses does not cause major disease, the metabolic activity of infected cells changes, thus affecting the activation of oncogenic signaling pathways. In the past few years, lots of studies have shown that viral infections can affect disease progression by regulating the transmission of multiple signaling pathways. This review aims to discuss the potential effects of virus infections on AHR signaling pathways so that we may find a new strategy to minimize the adverse effects of the AHR pathway on diseases. Video Abstract.

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.

Cellular Senescence in Immunity against Infections

Cellular senescence is characterized by irreversible cell cycle arrest in response to different triggers and an inflammatory secretome. Although originally described in fibroblasts and cell types of solid organs, cellular senescence affects most tissues with advancing age, including the lymphoid tissue, causing chronic inflammation and dysregulation of both innate and adaptive immune functions. Besides its normal occurrence, persistent microbial challenge or pathogenic microorganisms might also accelerate the activation of cellular aging, inducing the premature senescence of immune cells. Therapeutic strategies counteracting the detrimental effects of cellular senescence are being developed. Their application to target immune cells might have the potential to improve immune dysfunctions during aging and reduce the age-dependent susceptibility to infections. In this review, we discuss how immune senescence influences the host's ability to resolve more common infections in the elderly and detail the different markers proposed to identify such senescent cells; the mechanisms by which infectious agents increase the extent of immune senescence are also reviewed. Finally, available senescence therapeutics are discussed in the context of their effects on immunity and against infections.

Factors mediating cancer risk in systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE) are at an elevated risk for certain cancers compared to the population at large. Cancers seen at higher rates in the SLE population include hematologic malignancies, such as non-Hodgkin lymphoma, and cancers of the lung and thyroid. SLE patients also have a decreased risk for certain malignancies, such as breast cancer, melanoma, and prostate cancer. We review the literature on risk factors for malignancy in patients with SLE and discuss the exogenous and innate factors that are thought to contribute to the unique pattern of cancer risk observed in this patient population. These risk factors are important for providers of SLE patients to understand in order to maintain high clinical suspicion and detect malignancy as soon as possible. Further research is needed to determine the most effective guidelines on counseling patients on cancer screening and prevention.

Epstein-Barr virus perpetuates B cell germinal center dynamics and generation of autoimmune-associated phenotypes in vitro

Human B cells encompass functionally diverse lineages and phenotypic states that contribute to protective as well as pathogenic responses. Epstein-Barr virus (EBV) provides a unique lens for studying heterogeneous B cell responses, given its adaptation to manipulate intrinsic cell programming. EBV promotes the activation, proliferation, and eventual outgrowth of host B cells as immortalized lymphoblastoid cell lines (LCLs) in vitro, which provide a foundational model of viral latency and lymphomagenesis. Although cellular responses and outcomes of infection can vary significantly within populations, investigations that capture genome-wide perspectives of this variation at single-cell resolution are in nascent stages. We have recently used single-cell approaches to identify EBV-mediated B cell heterogeneity in de novo infection and within LCLs, underscoring the dynamic and complex qualities of latent infection rather than a singular, static infection state. Here, we expand upon these findings with functional characterizations of EBV-induced dynamic phenotypes that mimic B cell immune responses. We found that distinct subpopulations isolated from LCLs could completely reconstitute the full phenotypic spectrum of their parental lines. In conjunction with conserved patterns of cell state diversity identified within scRNA-seq data, these data support a model in which EBV continuously drives recurrent B cell entry, progression through, and egress from the Germinal Center (GC) reaction. This "perpetual GC" also generates tangent cell fate trajectories including terminal plasmablast differentiation, which constitutes a replicative cul-de-sac for EBV from which lytic reactivation provides escape. Furthermore, we found that both established EBV latency and de novo infection support the development of cells with features of atypical memory B cells, which have been broadly associated with autoimmune disorders. Treatment of LCLs with TLR7 agonist or IL-21 was sufficient to generate an increased frequency of IgD-/CD27-/CD23-/CD38+/CD138+ plasmablasts. Separately, de novo EBV infection led to the development of CXCR3+/CD11c+/FCRL4+ B cells within days, providing evidence for possible T cell-independent origins of a recently described EBV-associated neuroinvasive CXCR3+ B cell subset in patients with multiple sclerosis. Collectively, this work reveals unexpected virus-driven complexity across infected cell populations and highlights potential roles of EBV in mediating or priming foundational aspects of virus-associated immune cell dysfunction in disease.

CD8+ T Cell Phenotype and Function in Childhood and Adult-Onset Connective Tissue Disease

CD8+ T cells are cytotoxic lymphocytes that destroy pathogen infected and malignant cells through release of cytolytic molecules and proinflammatory cytokines. Although the role of CD8+ T cells in connective tissue diseases (CTDs) has not been explored as thoroughly as that of other immune cells, research focusing on this key component of the immune system has recently gained momentum. Aberrations in cytotoxic cell function may have implications in triggering autoimmunity and may promote tissue damage leading to exacerbation of disease. In this comprehensive review of current literature, we examine the role of CD8+ T cells in systemic lupus erythematosus, Sjögren's syndrome, systemic sclerosis, polymyositis, and dermatomyositis with specific focus on comparing what is known about CD8+ T cell peripheral blood phenotypes, CD8+ T cell function, and CD8+ T cell organ-specific profiles in adult and juvenile forms of these disorders. Although, the precise role of CD8+ T cells in the initiation of autoimmunity and disease progression remains to be elucidated, increasing evidence indicates that CD8+ T cells are emerging as an attractive target for therapy in CTDs.

IFN-γ, should not be ignored in SLE

Systemic lupus erythematosus (SLE) is a typical autoimmune disease with a complex pathogenesis and genetic predisposition. With continued understanding of this disease, it was found that SLE is related to the interferon gene signature. Most studies have emphasized the important role of IFN-α in SLE, but our previous study suggested a nonnegligible role of IFN-γ in SLE. Some scholars previously found that IFN-γ is abnormally elevated as early as before the classification of SLE and before the emergence of autoantibodies and IFN-α. Due to the large overlap between IFN-α and IFN-γ, SLE is mostly characterized by expression of the IFN-α gene after onset. Therefore, the role of IFN-γ in SLE may be underestimated. This article mainly reviews the role of IFN-γ in SLE and focuses on the nonnegligible role of IFN-γ in SLE to gain a more comprehensive understanding of the disease.

Abnormalities of T cells in systemic lupus erythematosus: new insights in pathogenesis and therapeutic strategies

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by loss of immune tolerance and sustained production of autoantibodies. Multiple and profound T cell abnormalities in SLE are intertwined with disease expression. Both numerical and functional disturbances have been reported in main CD4⁺ T helper cell subsets including Th1, Th2, Th17, regulatory, and follicular helper cells. SLE CD4⁺ T cells are known to provide help to B cells, produce excessive IL-17 but insufficient IL-2, and infiltrate tissues. In the absence of sufficient amounts of IL-2, regulatory T cells, do not function properly to constrain inflammation. A complicated series of early signaling defects and aberrant activation of kinases and phosphatases result in complex cell phenotypes by altering the metabolic profile and the epigenetic landscape. All main metabolic pathways including glycolysis, glutaminolysis and oxidative phosphorylation are altered in T cells from lupus prone mice and patients with SLE. SLE CD8⁺ cytotoxic T cells display reduced cytolytic activity which accounts for higher rates of infection and the sustenance of autoimmunity. Further, CD8⁺ T cells in the context of rheumatic diseases lose the expression of CD8, acquire IL-17⁺CD4^-CD8^- double negative T (DNT) cell phenotype and infiltrate tissues. Herein we present an update on these T cell abnormalities along with underlying mechanisms and discuss how these advances can be exploited therapeutically. Novel strategies to correct these aberrations in T cells show promise for SLE treatment.

CD38 reduces mitochondrial fitness and cytotoxic T cell response against viral infection in lupus patients by suppressing mitophagy

Infection is one of the major causes of mortality in patients with systemic lupus erythematosus (SLE). We previously found that CD38, an ectoenzyme that regulates the production of NAD+, is up-regulated in CD8+ T cells of SLE patients and correlates with the risk of infection. Here, we report that CD38 reduces CD8+ T cell function by negatively affecting mitochondrial fitness through the inhibition of multiple steps of mitophagy, a process that is critical for mitochondria quality control. Using a murine lupus model, we found that administration of a CD38 inhibitor in a CD8+ T cell-targeted manner reinvigorated their effector function, reversed the defects in autophagy and mitochondria, and improved viral clearance. We conclude that CD38 represents a target to mitigate infection rates in people with SLE.

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.

Epidemiology of the Epstein–Barr Virus in Autoimmune Inflammatory Rheumatic Diseases in Northern Brazil

The present study aimed to describe the seroprevalence infection, Epstein-Barr virus (EBV) genotypes, relate the infection’s profile with the epidemiological and corticotherapy data of patients with Autoimmune inflammatory rheumatic diseases (AIRD). A cross-sectional study was carried out with 139 individuals, 92 with systemic lupus erythematosus (SLE), 27 with rheumatoid arthritis (RA) and 20 with other autoimmune diseases, who were undergoing clinical follow-up in Brazil. Serological tests for the detection of EBV anti-VCA IgM and IgG antibodies, as well as the amplification of a segment of the EBV EBNA-3c gene by conventional PCR were performed to identify the infection and the viral subtype. The Epstein–Barr nuclear antigen 3 (EBNA3C) gene participates of maintenance of viral latency and infected B-lymphocytes immortalization by unclear signaling cascades. The association of active/latent EBV infection with EBV infection profile was assessed by Fisher’s exact test and multiple logistic regression. The seroprevalence of EBV anti-VCA IgG was 100%, while that of anti-VCA IgM was 1.43% (2/139). Active-phase infection was confirmed by the presence of EBV DNA in 40.29% of the population evaluated (56/139), with 45.65% (42/92) in SLE, 25.92% (7/27) in the RA and in 35% (7/20) in other autoimmune diseases. It was observed that individuals with SLE had a higher prevalence of active/lytic EBV infection and that oral corticosteroid therapy at a dose lower than 20 mg/day increased the risk of EBV activity by up to 11 times. Only the presence of EBV-1 was identified. Thus, EBV lytic infection was higher in individuals with SLE when compared to other autoimmune diseases with rheumatologic involvement and the lytic activity of the virus precedes corticosteroid-induced immunosuppression.

Association of Viral Infection With the Development and Pathogenesis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that causes multiple organ damage in women of childbearing age and has a relapsing-remitting course. SLE is caused by the interaction between genetic and environmental factors, however, its underlying triggers remain unknown. Among the environmental factors, the involvement of infections as a trigger for SLE, especially those of viral etiology, has been widely reported. Human endogenous retroviruses (HERVs) may put patients at a genetic predisposition to SLE, while the Epstein-Barr virus (EBV) may play a role as an environmental factor that triggers the development of SLE. It has been suggested that EBV-infected B-cells may become resistant to apoptosis, resulting in the activation, proliferation, and antibody production of autoreactive B-cells, which cause tissue damage in SLE. However, the interaction between the virus and immune cells, as well as the impact of the virus on the differentiation and dysfunction of immune cells, remain unclear. In this review, we focus on the relationship between the development and pathogenesis of SLE and viral infections, as well as the mechanism of SLE exacerbation via activation of immune cells, such as B-cells, based on the latest findings.

Evaluation of herpesvirus members on hospital admission in patients with systemic lupus erythematous shows higher frequency of Epstein-Barr virus and its associated renal dysfunction

INTRODUCTION

Members of the Herpesviridae family have been described in patients with systemic lupus erythematous (SLE), but the clinical impact on renal function is not well known.

METHODS

HSV1, HSV2, VZV, EBV, CMV, HHV-6, HHV-7, and HHV-8 were evaluated by molecular biology on admission in blood samples from 40 consecutive SLE patients hospitalized for lupus activity.

RESULTS

Patients were 90.0% female, 77.5% non-white, with average age of 32.7 ± 13.6 years. We found positivity for EBV (65.0%), CMV (30.0%), HSV-1 (30.0%), HHV-6 (12.5%), and HHV-7 (7.5%). For all viruses, age, SLEDAI, hematological tests, ferritin, LDH, C-reactive protein, and erythrocyte sedimentation rate (ESR) were not significant. However, EBV positivity was a significant factor for higher serum creatinine (3.0 ± 2.8 vs. 0.9 ± 0.8; P = 0.001) and urea (86 ± 51 vs. 50 ± 46; P = 0.03). Moreover, positive cases for EBV only or with combined co-infections (66.7%-CMV; 58.3%-HSV-1) or negative for EBV only were evaluated by Kruskal-Wallis test again showed statistical significance for serum creatinine and urea (both P ≤ 0.01), with posttest also showing statistical differences for renal dysfunction and EBV presence (alone or in combined co-infections). The presence of EBV viral load was also significant for nephrotic-range proteinuria, renal flare, and the need for hemodialysis.

CONCLUSION

Members of the Herpeviridae family (mainly EBV, HSV-1 and CMV) are common on hospital admission of SLE patients, reaching 65% for EBV, which seems to be associated with renal dysfunction and could reflect a previous association or overlapping disease, which is not well understood.

HLA-DR Expression Level in CD8+ T Cells Correlates With the Severity of Children With Acute Infectious Mononucleosis

Background

This study aimed to assess the host immune signatures associated with EBV infection and its clinical value in indicating the severity of children with acute infectious mononucleosis (IM).

Methods

Twenty-eight pediatric patients with IM aged 3–8 years were enrolled. The immune phenotypes and cytokine secretion capability of T cells were detected.

Results

The percentages and absolute numbers of CD3⁺ and CD8⁺ T cells were significantly increased in IM patients compared with HCs. The percentages of Naïve CD4⁺ and CD8⁺ T cells were decreased but with increased percentages of memory CD4⁺ and CD8⁺ T subsets. Our results showed the upregulation of active marker HLA-DR, TCR-αβ, and inhibitory receptors PD-1, TIGIT in CD8⁺ T cells from IM patients, which suggested that effective cytotoxic T cells were highly against EBV infection. However, EBV exposure impaired the cytokine (IFN-γ, IL-2, and TNF-α) secretion capability of CD4⁺ and CD8⁺ T cells after stimulation with PMA/ionomycin in vitro. Multivariate analysis revealed that the percentage of HLA-DR⁺ CD8⁺ T cells was an independent prognostic marker for IM. The percentage of HLA-DR⁺ CD8⁺ T cells was significantly correlated with high viral load and abnormal liver function results.

Conclusion

Robust expansion and upregulation of HLA-DR in CD8⁺ T cells, accompanied with impaired cytokine secretion, were typical characteristics of children with acute IM. The percentage of HLA-DR⁺ CD8⁺ T cells might be used as a prominent marker not only for the early diagnosis but also for indicating the severity of IM.

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.

The role of CD8+ T-cell systemic lupus erythematosus pathogenesis: an update

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) is a serious autoimmune disease with a wide range of organ involvement. In addition to aberrant B-cell responses leading to autoantibody production, T-cell abnormalities are important in the induction of autoimmunity and the ensuing downstream organ damage. In this article, we present an update on how subsets of CD8+ T cells contribute to SLE pathogenesis.

RECENT FINDINGS

Reduced cytolytic function of CD8+ T cells not only promotes systemic autoimmunity but also accounts for the increased risk of infections. Additional information suggests that effector functions of tissue CD8+ T cells contribute to organ damage. The phenotypic changes in tissue CD8+ T cells likely arise from exposure to tissue microenvironment and crosstalk with tissue resident cells. Research on pathogenic IL-17-producing double negative T cells also suggests their origin from autoreactive CD8+ T cells, which also contribute to the induction and maintenance of systemic autoimmunity.

SUMMARY

Reduced CD8+ T-cell effector function illustrates their role in peripheral tolerance in the control of autoimmunity and to the increased risk of infections. Inflammatory cytokine producing double negative T cells and functional defects of regulatory CD8+ T cell both contribute to SLE pathogenesis. Further in depth research on these phenotypic changes are warranted for the development of new therapeutics for people with SLE.

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.

Innate Immune Modulation Induced by EBV Lytic Infection Promotes Endothelial Cell Inflammation and Vascular Injury in Scleroderma

Microvascular injury is considered an initial event in the pathogenesis of scleroderma and endothelial cells are suspected of being the target of the autoimmune process seen in the disease. EBV has long been proposed as a trigger for autoimmune diseases, including scleroderma. Nevertheless, its contribution to the pathogenic process remains poorly understood. In this study, we report that EBV lytic antigens are detected in scleroderma dermal vessels, suggesting that endothelial cells might represent a target for EBV infection in scleroderma skin. We show that EBV DNA load is remarkably increased in peripheral blood, plasma and circulating monocytes from scleroderma patients compared to healthy EBV carriers, and that monocytes represent the prominent subsets of EBV-infected cells in scleroderma. Given that monocytes have the capacity to adhere to the endothelium, we then investigated whether monocyte-associated EBV could infect primary human endothelial cells. We demonstrated that endothelial cells are infectable by EBV, using human monocytes bound to recombinant EBV as a shuttle, even though cell-free virus failed to infect them. We show that EBV induces activation of TLR9 innate immune response and markers of vascular injury in infected endothelial cells and that up-regulation is associated with the expression of EBV lytic genes in infected cells. EBV innate immune modulation suggests a novel mechanism mediating inflammation, by which EBV triggers endothelial cell and vascular injury in scleroderma. In addition, our data point to up-regulation of EBV DNA loads as potential biomarker in developing vasculopathy in scleroderma. These findings provide the framework for the development of novel therapeutic interventions to shift the scleroderma treatment paradigm towards antiviral therapies.

Type I interferons affect the metabolic fitness of CD8+ T cells from patients with systemic lupus erythematosus

The majority of patients with systemic lupus erythematosus (SLE) have high expression of type I IFN-stimulated genes. Mitochondrial abnormalities have also been reported, but the contribution of type I IFN exposure to these changes is unknown. Here, we show downregulation of mitochondria-derived genes and mitochondria-associated metabolic pathways in IFN-High patients from transcriptomic analysis of CD4+ and CD8+ T cells. CD8+ T cells from these patients have enlarged mitochondria and lower spare respiratory capacity associated with increased cell death upon rechallenge with TCR stimulation. These mitochondrial abnormalities can be phenocopied by exposing CD8+ T cells from healthy volunteers to type I IFN and TCR stimulation. Mechanistically these 'SLE-like' conditions increase CD8+ T cell NAD+ consumption resulting in impaired mitochondrial respiration and reduced cell viability, both of which can be rectified by NAD+ supplementation. Our data suggest that type I IFN exposure contributes to SLE pathogenesis by promoting CD8+ T cell death via metabolic rewiring.

SARS-CoV-2 vaccines in patients with SLE

As the Moderna (mRNA-1273) and Pfizer/BioNTech (BNT162b2) vaccines become available to patients with autoimmune diseases and SLE, practitioners will have to inform them about the safety and efficacy of these vaccines. Here we discuss the challenges of applying vaccine data to patients with autoimmune diseases and the evidence available in the literature that may help in the decision process.

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.

Epstein Barr Virus and Autoimmune Responses in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease. Infections or infectious reactivation are potential triggers for initiation of autoimmunity and for SLE flares. Epstein-Barr virus (EBV) is gamma herpes virus that has been associated with several autoimmune diseases such as SLE, multiple sclerosis, Sjogren’s syndrome, and systemic sclerosis. In this review, we will discuss the recent advances regarding how EBV may contribute to immune dysregulation, and how these mechanisms may relate to SLE disease progression.

T Cell Abnormalities in the Pathogenesis of Systemic Lupus Erythematosus: an Update

PURPOSE OF REVIEW

Systemic lupus erythematosus is a complex disease with broad spectrum of clinical manifestations. In addition to abnormal B cell responsive leading to autoantibody production, various T cells also play different roles in promoting systemic autoimmunity and end organ damage. We aim to provide a review on recent developments in how abnormalities in different T cells subsets contribute to systemic lupus erythematosus pathogenesis and how they inform the consideration of new promising therapeutics.

RECENT FINDINGS

Distinct subsets of T cells known as T follicular helper cells enable the production of pathogenic autoantibodies. Detailed understanding of the B cell helping T cell subsets should improve the performance of clinical trials targeting the cognate T:B cell interaction. CD8⁺ T cells play a role in peripheral tolerance and reversal of its exhausted phenotype could potentially alleviate both systemic autoimmunity and the risk of infection. Research on the abnormal lupus T cell signaling also leads to putative therapeutic targets able to restore interleukin-2 production and suppress the production of the pathogenic IL-17 cytokine. Recently, several studies have focused on dissecting T cell populations located in the damaged organs, aiming to target the pathogenic processes specific to each organ. Numerous T cell subsets play distinct roles in SLE pathogenesis and recent research in understanding abnormal signaling pathways, cellular metabolism, and environmental cues pave the way for the development of novel therapeutics.

Preserved specific anti-viral T-cell response but associated with decreased lupus activity in SLE patients with cytomegalovirus infection

OBJECTIVES

SLE is an autoimmune disease characterized by aberrant autoantibody production and immune dysfunctions. Whether the anti-CMV immunity is impaired in SLE patients is poorly understood. We investigated the specific anti-viral T-cell response in SLE patients with CMV infection and its possible impacts on clinical manifestations in lupus.

METHODS

CD28 null T-cell percentages were measured by flow cytometry in 89 SLE patients and 58 healthy controls. A specific anti-CMV CD8 T-cell response was assessed ex vivo by the production of intracellular cytokines in response to CMV phosphoprotein 65 (pp65) by flow cytometry. Clinical manifestations and immune parameters were analysed in SLE patients according to their CMV serostatus.

RESULTS

CD28 null T cells were significantly expanded in SLE patients. When the anti-CMV pp65 CD8 polyfunctional T cell response was analysed, as defined by production of at least three of four functional cytokines or effectors (intracellular IFN-γ, IL-2, TNF-α and surface CD107a), the results demonstrated that it was not impaired in SLE patients. In contrast, when comparing clinical manifestations, there were lower anti-ds-DNA levels and decreased SLEDAI in SLE patients with CMV infection. Furthermore, the expansion of CD4+CD28 null T cells was negatively associated with anti-ds-DNA levels and SLEDAI in these lupus patients.

CONCLUSION

In SLE patients with CMV infection, the specific anti-CMV CD8 T-cell response is preserved but is associated with decreased disease activity and lower anti-DNA levels among these patients, suggesting CMV infection may mitigate lupus activity.

Targeting the signaling in Epstein-Barr virus-associated diseases: mechanism, regulation, and clinical study

Epstein–Barr virus-associated diseases are important global health concerns. As a group I carcinogen, EBV accounts for 1.5% of human malignances, including both epithelial- and lymphatic-originated tumors. Moreover, EBV plays an etiological and pathogenic role in a number of non-neoplastic diseases, and is even involved in multiple autoimmune diseases (SADs). In this review, we summarize and discuss some recent exciting discoveries in EBV research area, which including DNA methylation alterations, metabolic reprogramming, the changes of mitochondria and ubiquitin-proteasome system (UPS), oxidative stress and EBV lytic reactivation, variations in non-coding RNA (ncRNA), radiochemotherapy and immunotherapy. Understanding and learning from this advancement will further confirm the far-reaching and future value of therapeutic strategies in EBV-associated diseases.

The CD38/NAD/SIRTUIN1/EZH2 Axis Mitigates Cytotoxic CD8 T Cell Function and Identifies Patients with SLE Prone to Infections

Patients with systemic lupus erythematosus (SLE) suffer frequent infections that account for significant morbidity and mortality. T cell cytotoxic responses are decreased in patients with SLE, yet the responsible molecular events are largely unknown. We find an expanded CD8CD38^high T cell subset in a sub-group of patients with increased rates of infections. CD8CD38^high T cells from healthy subjects and patients with SLE display decreased cytotoxic capacity, degranulation, and expression of granzymes A and B and perforin. The key cytotoxicity-related transcription factors T-bet, RUNX3, and EOMES are decreased in CD8CD38^high T cells. CD38 leads to increased acetylated EZH2 through inhibition of the deacetylase Sirtuin1. Acetylated EZH2 represses RUNX3 expression, whereas inhibition of EZH2 restores CD8 T cell cytotoxic responses. We propose that high levels of CD38 lead to decreased CD8 T cell-mediated cytotoxicity and increased propensity to infections in patients with SLE, a process that can be reversed pharmacologically.

Katsuyama et al. find that an expanded CD8CD38^high T cell population in SLE patients is linked to infections. CD8CD38^high T cells display decreased cytotoxic capacity by suppressing the expression of related molecules through an NAD⁺/Sirtuin1/EZH2 pathway. EZH2 inhibitors increase cytotoxicity offering a means to mitigate infection rates in SLE.

Clinical application of Epstein-Barr virus DNA loads in Epstein-Barr virus-associated diseases: A cohort study

OBJECTIVES

This study evaluated the diagnostic value of Epstein-Barr virus (EBV) DNA load in blood samples of patients with EBV-associated diseases, and proposed a strategy for the interpretation of positive EBV DNA results.

METHODS

Derivation and validation cohorts were established to evaluate the clinical significance of EBV DNA loads in the peripheral blood mononuclear cells (PBMCs) and plasma from EBV-infected patients. EBV DNA loads were compared and receiver operating characteristic curves were employed to assess the optimal cutoff values of EBV DNA for identification of EBV-associated diseases.

RESULTS

The derivation and validation cohorts comprised 135 and 71 subjects, respectively. EBV DNA loads in the PBMCs of the EBV-associated diseases group was significantly higher than that of the EBV non-associated diseases group (5.8 × 10⁴ vs 7.8 × 10³ copies/10⁶ cells, P<0.0001). The diagnostic cut-off value of viral load in PBMCs for EBV-associated diseases was determined to be 1.6 × 10⁴ copies/10⁶ cells. The combined EBV DNA load cutoff in PBMCs and positive EBV DNA qualitative detection in plasma (>500 copies/mL) allowed for the differentiation of EBV-associated and non-associated diseases; the sensitivity and specificity were 80.6 and 96.8%, respectively.

CONCLUSIONS

The strategy of combining EBV DNA loads in PBMCs and plasma will potentially help identify EBV-associated diseases.

Prevalence of seropositivity of selected herpesviruses in patients with multiple sclerosis in the North of Jordan

Background

Multiple sclerosis (MS) is a neurological disease that is caused by an autoimmune response that results in the neuron’s demyelination in the central nervous system. The exact etiology of MS is not clear; however, several environmental and genetic factors are believed to participate in its initiation and development, including exposure to viruses. This study aims to investigate the association between the seropositivity and antibody titer of selected herpesviruses and MS in Jordanian MS patients.

Method

In this study, 55 MS patients and 40 age- and gender-matching apparently healthy volunteers were recruited from two main hospitals in the north of Jordan. MS patients were grouped into three types of MS based on the clinical presentation of the disease. Blood samples were collected from the participants and the IgG antibodies for human herpesvirus 6 (HHV-6), Epstein-Barr virus (EBV) nuclear antigen (EBNA), EBV viral capsid antigen (VCA) and varicella-zoster virus (VZV) were assayed by ELISA. The prevalence of seropositivity and the antibody level for each of the antibodies were compared between MS patients and controls and between the three types of MS.

Results

There was no significant difference in the prevalence of seropositivity and in the levels of antibodies for HHV-6, EBNA and VCA between MS patients and controls and between the three types of MS. In contrast, the number of seropositive patients and the level of IgG antibodies for VZV were significantly higher in MS patients compared to the control.

Conclusion

This study showed that patients with MS in the north of Jordan were more likely to be seropositive for VZV than the general population. Based on this finding, we recommend further studies to evaluate the seropositivity to VZV to be carried out in other parts of Jordan and the greater middle east to find out if there is a correlation between MS and previous infection with VZV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-020-01977-w.

Immune Checkpoints in Viral Infections

As evidence has mounted that virus-infected cells, such as cancer cells, negatively regulate the function of T-cells via immune checkpoints, it has become increasingly clear that viral infections similarly exploit immune checkpoints as an immune system escape mechanism. Although immune checkpoint therapy has been successfully used in cancer treatment, numerous studies have suggested that such therapy may also be highly relevant for treating viral infection, especially chronic viral infections. However, it has not yet been applied in this manner. Here, we reviewed recent findings regarding immune checkpoints in viral infections, including COVID-19, and discussed the role of immune checkpoints in different viral infections, as well as the potential for applying immune checkpoint blockades as antiviral therapy.

Role of Viral Infections in the Pathogenesis of Sjögren's Syndrome: Different Characteristics of Epstein-Barr Virus and HTLV-1

Viruses are possible pathogenic agents in several autoimmune diseases. Sjögren’s syndrome (SS), which involves exocrine dysfunction and the appearance of autoantibodies, shows salivary gland- and lacrimal gland-oriented clinical features. Epstein-Barr virus (EBV) is the most investigated pathogen as a candidate that directly induces the phenotype found in SS. The reactivation of the virus with various stimuli induced a dysregulated form of EBV that has the potential to infect SS-specific B cells and plasma cells that are closely associated with the function of an ectopic lymphoid structure that contains a germinal center (GC) in the salivary glands of individuals with SS. The involvement of human T-cell leukemia virus type 1 (HTLV-1) in SS has been epidemiologically established, but the disease concept of HTLV-1-associated SS remains unexplained due to limited evidence from basic research. Unlike the cell-to-cell contact between lymphocytes, biofilm-like structures are candidates as the mode of HTLV-1 infection of salivary gland epithelial cells (SGECs). HTLV-1 can infect SGECs with enhanced levels of inflammatory cytokines and chemokines that are secreted from SGECs. Regardless of the different targets that viruses have with respect to affinitive lymphocytes, viruses are involved in the formation of pathological alterations with immunological modifications in SS.

Deltex1 suppresses T cell function and is a biomarker for diagnosis and disease activity of systemic lupus erythematosus

OBJECTIVE

Deletion of Deltex1 (DTX1) in mice caused hyperactivation of T cells and lupus-like autoimmune syndromes, however, the association of DTX1 with human autoimmune diseases is totally unknown. This study investigated the role of DTX1 in human T cell functions and its correlation with disease activity in patients with SLE.

METHODS

The influence of DTX1 on T cell function was evaluated using human primary cells. DTX1 expression in peripheral blood mononuclear cells (PBMCs) from healthy controls and SLE patients was measured by quantitative real-time PCR and the SLEDAI was used to assess disease activity.

RESULTS

After stimulation with anti-CD3 and anti-CD28, silencing of DTX1 expression enhanced IFN-γ secretion by human T cells. The expression of DTX1 in PBMCs was significantly lower in 100 SLE patients than in 50 age- and sex-matched healthy controls (DTX1/glyceraldehyde 3-phosphate dehydrogenase, 0.452 vs 1.269, P < 0.001). The area under the receiver operator characteristics curve of the model was 0.737 (95% CI 0.658, 0.815). Intriguingly, a low DTX1 level in T cells led to high IFN-γ production in SLE patients and had a correlation with severe disease activity. In addition, low DTX1 expression in SLE patients was associated with active LN, lung involvement or hypocomplementaemia.

CONCLUSION

Knockdown DTX1 expression in human T cells reduced IFN-γ secretion. DTX1 expression in the PBMCs was significantly lower in SLE patients and had an inverse correlation with disease activity, indicating that the DTX1 level may be a good disease marker of SLE.

Gammaherpesviruses and B Cells: A Relationship That Lasts a Lifetime

Gammaherpesviruses are highly prevalent pathogens that establish life-long infection and are associated with diverse malignancies, including lymphoproliferative diseases and B cell lymphomas. Unlike other viruses that either do not infect B cells or infect B cells transiently, gammaherpesviruses manipulate physiological B cell differentiation to establish life-long infection in memory B cells. Disruption of such viral manipulation by genetic or environmental causes is likely to seed viral lymphomagenesis. In this review, we discuss physiological and unique host and viral mechanisms usurped by gammaherpesviruses to fine tune host B cell biology for optimal infection establishment and maintenance.

CD8+ T cells retain protective functions despite sustained inhibitory receptor expression during Epstein-Barr virus infection in vivo

Epstein Barr virus (EBV) is one of the most ubiquitous human pathogens in the world, persistently infecting more than 90% of the adult human population. It drives some of the strongest human CD8⁺ T cell responses, which can be observed during symptomatic primary infection known as infectious mononucleosis (IM). Despite high viral loads and prolonged CD8⁺ T cell stimulation during IM, EBV enters latency and is under lifelong immune control in most individuals that experience this disease. We investigated whether changes in T cell function, as frequently characterized by PD-1 up-regulation, occur during IM due to the prolonged exposure to high antigen levels. We readily detected the expansion of PD-1 positive CD8⁺ T cells together with high frequencies of Tim-3, 2B4, and KLRG1 expression during IM and in mice with reconstituted human immune system components (huNSG mice) that had been infected with a high dose of EBV. These PD-1 positive CD8⁺ T cells, however, retained proliferation, cytokine production, and cytotoxic abilities. Multiple subsets of CD8⁺ T cells expanded during EBV infection, including PD-1⁺Tim-3⁺KLRG1⁺ cells that express CXCR5 and TCF-1 germinal center homing and memory markers, and may also contain BATF3. Moreover, blocking the PD-1 axis compromised EBV specific immune control and resulted in virus-associated lymphomagenesis. Finally, PD-1⁺, Tim-3⁺, and KLRG1⁺ CD8⁺ T cell expansion coincided with declining viral loads during low dose EBV infection. These findings suggest that EBV infection primes PD-1 positive CD8⁺ T cell populations that rely on this receptor axis for the efficient immune control of this ubiquitous human tumor virus.

Since its discovery as a tumor virus by Epstein and colleagues in 1964, Epstein-Barr virus (EBV) has been implicated in many serious diseases, including infectious mononucleosis, Burkitt’s lymphoma, and post-transplant lymphoproliferative disease. Currently, in vivo studies are lacking to understand the comprehensive immune control of EBV in most healthy virus carriers, and, in particular, the characteristics of the CD8⁺ T cells involved in this process. We find that even though CD8⁺ T cells express multiple inhibitory receptors including PD-1 during primary EBV infection, they appear to retain an ability to produce cytokines, to kill infected cells, and to proliferate. Importantly, blocking the PD-1 pathway leads to defects in EBV-specific control and increased virus-induced tumor formation, indicating that this axis is important for viral control. This is in contrast to previous studies where releasing an inhibitory block is important for reinvigorating immune responses against cancer. Because PD-1 function is required to keep EBV in check, this study provides evidence against blocking co-inhibitory pathways in disease settings that require improved immune control of chronic virus infections.

The role of viral infections in the development of autoimmune diseases

The exact aetiology of most autoimmune diseases remains unknown, nonetheless, several factors contributing to the induction or exacerbation of autoimmune reactions have been suggested. These include the genetic profile and lifestyle of the affected individual in addition to environmental triggers such as bacterial, parasitic, fungal and viral infections. Infections caused by viruses usually trigger a potent immune response that is necessary for the containment of the infection; however, in some cases, a failure in the regulation of this immune response may lead to harmful immune reactions directed against the host's antigens. The autoimmune attack can be carried out by different arms and components of the immune system and through different possible mechanisms including molecular mimicry, bystander activation, and epitope spreading among others. In this review, we examine the data available for the involvement of viral infections in triggering or exacerbating autoimmune diseases in addition to discussing the mechanisms by which these viral infections and the immune pathways they trigger possibly contribute to the development of autoimmunity.