Increased frequency of EBV-specific effector memory CD8+ T cells correlates with higher viral load in rheumatoid arthritis

Altered EBV specific immune control in multiple sclerosis

Since the 1980s it is known that immune responses to the Epstein-Barr virus (EBV) are elevated in multiple sclerosis (MS) patients. Recent seroepidemiologial data have shown that this alteration after primary EBV infection identifies individuals with a more than 30-fold increased risk to develop MS. The mechanisms by which EBV infection might erode tolerance for the central nervous system (CNS) in these individuals, years prior to clinical MS onset, remain unclear. In this review I will discuss altered frequencies of EBV life cycle stages and their tissue distribution, EBV with CNS autoantigen cross-reactive immune responses and loss of immune control for autoreactive B and T cells as possible mechanisms. This discussion is intended to stimulate future studies into these mechanisms with the aim to identify candidates for interventions that might correct EBV specific immune control and/or resulting cross-reactivities with CNS autoantigens in MS patients and thereby ameliorate disease activity.

Antibody Cross-Reactivity in Auto-Immune Diseases

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

Immune dysregulation and pathogenic pathways mediated by common infections in rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the world's most prevalent inflammatory autoimmune diseases, affecting between 0.4 and 1.3% of the population. The susceptibility to RA appears to be influenced by a complex interaction between a favorable genetic background and the existence of a specific immune reaction against a wide range of environmental variables. Among the known environmental variables, infections are believed to have a significant role in promoting the formation of autoimmune disorders, which are frequently caused by specific microorganisms. Infections have been linked to RA in recent medical studies. In this study, we selected the most prevalent infections associated with RA from the literature and described the data confirming their pathogenic role in RA. Our investigation included Mycobacterium, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Proteus mirabilis, Epstein-Barr virus, parvovirus, and Prevotella copri.

Clinicopathological findings, prognosis, and Epstein-Barr virus infection in rheumatoid arthritis patients with other iatrogenic immunodeficiency-associated T- and NK-cell lymphoproliferative disorders

BACKGROUND

Other iatrogenic immunodeficiency-associated (OIIA) T- and natural killer (NK)-cell lymphoproliferative disorders (TNK-LPDs) are rare in patients with rheumatoid arthritis (RA).

METHODS

We investigated the clinicopathological characteristics, Epstein-Barr virus (EBV) infection, genetic findings, therapeutic response, and prognostic factors in 21 RA patients with OIIA TNK-LPDs and compared these with those of 39 with OIIA B-cell LPDs (B-LPDs) and 22 with non-OIIA B-LPDs.

RESULTS

Immunohistologically, 11 patients (52%) showed CD4+ T-LPDs, and 7 had a T follicular helper (TFH) phenotype. The other nine patients (43%) showed CD8+ T-LPDs, and the remaining one (5%) had features of CD3+ CD4- CD8- nasal type TNK-cell lymphoma. CD30+, p53+, and CMYC+ atypical lymphocytes were identified in seven (33%), eight (38%), and five (24%) patients, respectively. In situ hybridisation detected EBV-encoded RNA (EBER) + large atypical lymphocytes in five patients (24%). Nine of 17 patients (53%) showed clonal peaks of TCRγ by polymerase chain reaction. Withdrawal of MTX and biologic drugs was effective in 12 patients (57%), and 8 (38%) received chemotherapies. Two patients with TFH+ or EBV+ CD4+ CD30+ large cell peripheral T-cell lymphoma, one with CD8+ systemic anaplastic large cell lymphoma, and two with systemic EBV+ CD8+ T-cell lymphoma of childhood showed a lethal progressive clinical course within 13 months. Moreover, > 500 U/L LDH, large atypical lymphocytes, expression of CD30, p53, and CMYC, and EBER+ atypical lymphocytes were significantly poor prognostic factors for overall survival (p < 0.05). Median interval from RA onset to OIIA TNK-LPDs was 72 months, which was shorter than 166 months in OIIA B-LPDs (p = 0.003). EBV+ atypical and reactive lymphocytes were frequently found in 15 patients with OIIA TNK-LPDs (71%), in 27 with OIIA B-LPDs (69%), and only in 3 with non-OIIA B-LPDs (14%).

CONCLUSIONS

OIIA TNK-LPDs occurred in early phase of RA, compared with OIIA B-LPDs, and occasionally showed a lethal progressive clinical course. Detection of OIIA TNK-LPD patients with poor prognostic factors is necessary. EBV infection in immunosuppressed patients due to persistent RA, MTX, and biologic drugs may play a role in forming the tumour microenvironment and lymphomagenesis of TNK-LPDs.

Dysbiotic Oral and Gut Viromes in Untreated and Treated Rheumatoid Arthritis Patients

Rheumatoid arthritis (RA) is influenced by oral and gut bacteria; however, much less is known about the relationship between oral or gut viromes and RA. Here, we performed whole-oral- and whole-gut-virome analyses based on shotgun sequencing of 497 samples. A comparative analysis of the oral and gut viromes in healthy controls and untreated and treated RA patients was performed, and system interaction networks among viruses, bacteria, and RA-associated clinical indices were constructed to address the potential relationship between the virome and RA by principal-coordinate analysis, distance-based redundancy analysis, permutational multivariate analysis, Spearman correlation coefficient analysis, and random-forest model analysis. The results showed that the viromes could be profiled in dental plaque, saliva, and fecal samples, among which saliva had the highest within-sample diversity. Importantly, significantly different diversities and compositions of the oral (i.e., dental plaque and saliva) viromes were observed not only between RA patients and healthy controls but also between untreated and treated RA patients, yet there were relatively minor differences in the gut viromes. Furthermore, to understand how these viruses affected the bacteriome, a virus-bacterium interaction network was constructed from dental plaque, saliva, and fecal samples of RA patients. Additionally, some RA-associated oral taxa, including Lactococcus phage (vOTU70), Bacteroides vulgatus, Lactococcus lactis, Escherichia coli, and Neisseria elongata, were correlated with the RA-related clinical indices. Whole-virome analysis illustrated the potential role of the oral and gut viromes in affecting our body either directly or via bacteria, which characterized neglected and new candidates contributing to the development of RA. IMPORTANCE Our results demonstrated community variation among dental plaque, saliva, and fecal viromes. In oral and gut samples from untreated and treated RA patients, the perturbance of viral composition and the correlation network of microbes and RA-associated clinical indices might be involved in the pathogenicity of RA. The findings in this study expand the knowledge of the potential role of oral and gut viral communities in the development of RA and may contribute to research on correlations between viruses and other diseases.

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

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

Identifying the hub genes and immune cell infiltration in synovial tissue between osteoarthritic and rheumatoid arthritic patients by bioinformatic approach

BACKGROUND

Osteoarthritis (OA) and rheumatoid arthritis (RA) are two common diseases that result in limb disability and a decrease in quality of life. The major symptoms of OA and RA are pain, swelling, stiffness, and malformation of joints, and each disease also has unique characteristics.

OBJECTIVE

To compare the pathological mechanisms of OA and RA via weighted correlation network analysis (WGCNA) and immune infiltration analysis and find potential diagnostic and pharmaceutical targets for the treatment of OA and RA.

METHODS

The gene expression profiles of ten OA and ten RA synovial tissue samples were downloaded from the Gene Expression Omnibus (GEO) database (GSE55235). After obtaining differentially expressed genes (DEGs) via GEO2R, WGCNA was conducted using an R package, and modules and genes that were highly correlated with OA and RA were identified. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and protein-protein interaction (PPI) network analyses were also conducted. Hub genes were identified using the Search Tool for the Retrieval of Interacting Genes (STRING) and Cytoscape software. Immune infiltration analysis was conducted using the Perl program and CIBERSORT software.

RESULTS

Two hundred ninety-nine DEGs, 24 modules, 16 GO enrichment terms, 6 KEGG pathway enrichment terms, 10 hub genes (CXCL9, CXCL10, CXCR4, CD27, CD69, CD3D, IL7R, STAT1, RGS1, and ISG20), and 8 kinds of different infiltrating immune cells (plasma cells, CD8 T cells, activated memory CD4 T cells, T helper follicular cells, M1 macrophages, Tregs, resting mast cells, and neutrophils) were found to be involved in the different pathological mechanisms of OA and RA.

CONCLUSION

Inflammation-associated genes were the top differentially expressed hub genes between OA and RA, and their expression was downregulated in OA. Genes associated with lipid metabolism may have upregulated expression in OA. In addition, immune cells that participate in the adaptive immune response play an important role in RA. OA mainly involves immune cells that are associated with the innate immune response.

Epstein Barr Virus Exploits Genetic Susceptibility to Increase Multiple Sclerosis Risk

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) for which both genetic and environmental risk factors have been identified. The strongest synergy among them exists between the MHC class II haplotype and infection with the Epstein Barr virus (EBV), especially symptomatic primary EBV infection (infectious mononucleosis) and elevated EBV-specific antibodies. In this review, we will summarize the epidemiological evidence that EBV infection is a prerequisite for MS development, describe altered EBV specific immune responses in MS patients, and speculate about possible pathogenic mechanisms for the synergy between EBV infection and the MS-associated MHC class II haplotype. We will also discuss how at least one of these mechanisms might explain the recent success of B cell-depleting therapies for MS. While a better mechanistic understanding of the role of EBV infection and its immune control during MS pathogenesis is required and calls for the development of innovative experimental systems to test the proposed mechanisms, therapies targeting EBV-infected B cells are already starting to be explored in MS patients.

Transcriptome Analysis Reveals the Molecular Immunological Characteristics of Lesions in Patients with Halo Nevi When Compared to Stable Vitiligo, Normal Nevocytic Nevi and Cutaneous Melanoma

Background

Given their similar appearance and histology, halo nevi (HN) were considered as a type of vitiligo. However, whether HN have stronger immune response than stable vitiligo (VL) remains unclear. In addition, the molecular alterations in HN compared with normal nevocytic nevi (NN) and primary cutaneous melanoma (MM) must be determined. This study aimed to systematically characterize the molecular immunological features of HN.

Methods

Skin samples from patients with HN, VL, NN, and MM were obtained with informed consent. Each of the four groups underwent transcriptome sequencing and data analysis were for pairwise comparison. Quantitative real-time PCR (RT-qPCR) was conducted to confirm the transcriptional expression of some differentially expressed genes (DEGs) that were closely related to immunity.

Results

A total of 441 and 1507 DEGs were found in the HN/NN and HN/MM groups, respectively. Compared with those of VL, HN lesions contained 162 up-regulated DEGs and 12 down-regulated DEGs. Bioinformatics analysis showed that the up-regulated genes in HN were substantially enriched in immune response, immune deficiency, and immune rejection; biological stimulation (virus, bacteria); and proliferation and activation of immune cells. Immune cell composition analysis also confirmed high expression levels of multiple immunocytes in HN.

Conclusion

The molecular immune mechanisms of HN and VL were similar, but the immune activity of HN was stronger than that of VL. Innate and adaptive immunity were involved in the pathogenesis and progression of HN and VL.

Latent gammaherpesvirus exacerbates arthritis through modification of age-associated B cells

Epstein-Barr virus (EBV) infection is associated with rheumatoid arthritis (RA) in adults, though the nature of the relationship remains unknown. Herein, we have examined the contribution of viral infection to the severity of arthritis in mice. We have provided the first evidence that latent gammaherpesvirus infection enhances clinical arthritis, modeling EBV's role in RA. Mice latently infected with a murine analog of EBV, gammaherpesvirus 68 (γHV68), develop more severe collagen-induced arthritis and a Th1-skewed immune profile reminiscent of human disease. We demonstrate that disease enhancement requires viral latency and is not due to active virus stimulation of the immune response. Age-associated B cells (ABCs) are associated with several human autoimmune diseases, including arthritis, though their contribution to disease is not well understood. Using ABC knockout mice, we have provided the first evidence that ABCs are mechanistically required for viral enhancement of disease, thereby establishing that ABCs are impacted by latent gammaherpesvirus infection and provoke arthritis.

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.

Association between EBV serological patterns and lymphocytic profile of SjS patients support a virally triggered autoimmune epithelitis

Sjögren's syndrome (SjS) is characterized by lymphocytic infiltration of exocrine glands, i.e. autoimmune epithelitis. Lymphocytes are central in SjS pathogenesis, with B-cell hyperactivity mediated by T-cells. B-cells are main targets of Epstein-Barr virus (EBV) infection, a frequently-suggested trigger for SjS. We aimed to evaluate how the EBV infection modulates B and T-cell subsets in SjS, including as controls Rheumatoid arthritis patients (RA) and healthy participants (HC). SjS patients presented decreased CXCR5⁺T-cells, although IL21-secreting Tfh and Tfc cells were increased. Tfc were positively correlated with ESSDAI scores, suggesting their relevant role in SjS pathogenesis. As previously described, SjS patients showed expanded circulating naïve B-cell compartments. SjS patients had a higher incidence of EBV-EA-D-IgG⁺ antibodies, characteristic of recent EBV-infection/reactivation. SjS patients with past infection or recent infection/reactivation showed increased CXCR3⁺Th1 and CXCR3⁺Tfh1 cells compared to those without active infection. SjS patients with a recent infection/reactivation profile presented increased transitional B-cells compared to patients with past infection and increased plasmablasts, compared to those without infection. Our results suggest EBV-infection contributes to B and T-cell differentiation towards the effector phenotypes typical of SjS. Local lymphocyte activation at ectopic germinal centres, mediated by Tfh and Tfc, can be EBV-driven, perpetuating autoimmune epithelitis, which leads to gland destruction in SjS.

Role of Infections in the Pathogenesis of Rheumatoid Arthritis: Focus on Mycobacteria

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease characterized by chronic erosive polyarthritis. A complex interaction between a favorable genetic background, and the presence of a specific immune response against a broad-spectrum of environmental factors seems to play a role in determining susceptibility to RA. Among different pathogens, mycobacteria (including Mycobacterium avium subspecies paratuberculosis, MAP), and Epstein–Barr virus (EBV), have extensively been proposed to promote specific cellular and humoral response in susceptible individuals, by activating pathways linked to RA development. In this review, we discuss the available experimental and clinical evidence on the interplay between mycobacterial and EBV infections, and the development of the immune dysregulation in RA.

Intracellular virus sensor MDA5 exacerbates vitiligo by inducing the secretion of chemokines in keratinocytes under virus invasion

Vitiligo is a disfiguring disease featuring chemokines-mediated cutaneous infiltration of autoreactive CD8+ T cells that kill melanocytes. Copious studies have indicated that virus invasion participates in the pathogenesis of vitiligo. IFIH1, encoding MDA5 which is an intracellular virus sensor, has been identified as a vitiligo susceptibility gene. However, the specific role of MDA5 in melanocyte death under virus invasion is not clear. In this study, we first showed that the expression of anti-CMV IgM and MDA5 was higher in vitiligo patients than healthy controls. Then, by using Poly(I:C) to imitate virus invasion, we clarified that virus invasion significantly activated MDA5 and further potentiated the keratinocyte-derived CXCL10 and CXCL16 which are the two vital chemokines for the cutaneous infiltration of CD8+ T cells in vitiligo. More importantly, IFN-β mediated by the MDA5-MAVS-NF-κB/IRF3 signaling pathway orchestrated the secretion of CXCL10 via the JAK1-STAT1 pathway and MDA5-meidiated IRF3 transcriptionally induced the production of CXCL16 in keratinocytes under virus invasion. In summary, our results demonstrate that MDA5 signaling orchestrates the aberrant skin immunity engaging in melanocyte death via mediating CXCL10 and CXCL16 secretion, which supports MDA5 as a potential therapeutic target for vitiligo under virus invasion.

CD28- Cells Are Increased in Early Rheumatoid Arthritis and Are Linked With Cytomegalovirus Status

Objective: CD3⁺CD8⁺CD28⁻ cells are higher in Rheumatoid Arthritis (RA). The aim of this study was to assess CD3⁺CD8⁺CD28⁻ cells in patients with early RA and assess the effects of cytomegalovirus (CMV) seropositivity.

Method: In this prospective observation study, 50 RA patients were recruited from Cardiff University Hospital of Wales (UHW) rheumatology outpatient, 25 patients with early disease (disease duration 0–6 months) and 25 patients with established disease (>2 years). These were compared with 25 healthy controls. Clinical and serological markers of inflammation were noted, and peripheral blood mononuclear cells were analyzed using flow cytometry.

Results: The percentage of the CD8⁺CD28⁻ T cells was increased in RA patients and was associated with disease duration. The percentage of CD8⁺CD28⁻ T cells was increased in CMV positive early and established RA grouped and early RA patients in comparison to CMV negative patients (p < 0.05). There is a weak but statistically significant correlation between the percentage of CD3⁺CD8⁺CD28⁻ cells and CRP in CMV positive RA patients (r = 0.227, p < 0.05).

Conclusion: The percentage of CD8⁺CD28⁻ T cells is higher in RA patients and correlates with disease duration, highlighting a potential role early in the disease process. These cells were also higher in CMV positive early RA patients which may suggest a role of CMV in disease development.

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

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

The Infectious Basis of ACPA-Positive Rheumatoid Arthritis

Rheumatoid arthritis (RA) is associated with HLA-DRB1 shared epitope (HLA-DRB1SE) and anti-citrullinated protein autoantibodies (ACPAs). ACPAs precedes the onset of clinical and subclinical RA. There are strong data for three infectious agents as autoimmunity triggers in RA, namely Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans causes of periodontal disease (PD), and Epstein-Barr virus (EBV). P. gingivalis expresses arginine gingipains, that cleave proteins at the arginine residues, and peptidyl arginine deiminase (PPAD), which citrullinates arginine residues of proteins, thus forming neoantigens that lead to ACPA production. Peripheral blood plasmablasts from ACPA+RA patients produce ACPAs the majority of which react against P. gingivalis. A. actinocycetemcomitans produces leukotoxin A, a toxin that forms pores in the neutrophil membranes and leads to citrullination and release of citrullinated autoantigens in the gums. EBV can infect B cells and epithelial cells and resides as latent infection in resting B cells. Abs against citrullinated peptides derived from EBV nuclear antigen appear years before RA and cross-react with human citrullinated fibrin. Citrullinated proteins are potential arthritogenic autoantigens in RA. The conversion of arginine to citrulline increases the peptide binding affinity to HLA-DRB1SE. Also, citrullinated fibrinogen induces arthritis in HLA-DRB1^*0401 transgenic mice, and transfer of their splenic T cells causes arthritis to recipient mice.

Systematic review and meta-analysis of the sero-epidemiological association between Epstein-Barr virus and rheumatoid arthritis

Introduction

Infection with Epstein-Barr virus (EBV) has been suggested to contribute to the pathogenesis of autoimmune diseases, including rheumatoid arthritis (RA). We sought to determine whether prior infection with the virus occurs more frequently in patients with RA compared to controls.

Methods

We performed a systematic review and meta-analyses of studies that reported the prevalence of anti-EBV antibodies in the sera of cases with RA and controls by searching Medline and Embase databases from 1946 to 2014, with no language restriction. Mantel-Haenszel odds ratios for the detection of anti-EBV antibodies were calculated, and meta-analyses conducted. Quality assessments were performed using a modified version of the Newcastle-Ottawa scale.

Results

Twenty-three studies were included. Quality assessment found most studies reported acceptable selection criteria but poor descriptions of how cases and controls were recruited. When all studies were included, there was a statistically significant higher seroprevalence of anti-VCA IgG in patients with RA compared to controls with an odds ratio (OR) of 1.61 (95 % confidence interval (CI) 1.05–2.46, p = 0.03), which is a similar-sized summary OR to that reported for systemic lupus erythematosus (SLE). However, when studies were restricted to those reporting more plausible levels of exposure to EBV in the control groups, no significant association was apparent, OR 1.47 (95 % CI 0.88–2.46, p = 0.14). Using anti-EBNA 1 or anti-EA IgG as markers of previous infection also did not yield significant associations (OR 1.05, 95 % CI 0.68–1.61, p = 0.82; OR 2.2, 95 % CI 0.86–5.65, p = 0.10 respectively).

Conclusions

Overall, these findings do not demonstrate an association between EBV seroprevalence and RA and therefore do not support the hypothesis that prior infection with EBV predisposes to the development of RA. This contrasts with meta-analyses that indicate EBV infection is associated with multiple sclerosis and SLE.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0755-6) contains supplementary material, which is available to authorized users.

Measurement of CD8+ and CD4+ T Cell Frequencies Specific for EBV LMP1 and LMP2a Using mRNA-Transfected DCs

An EBV-specific cellular immune response is associated with the control of EBV-associated malignancies and lymphoproliferative diseases, some of which have been successfully treated by adoptive T cell therapy. Therefore, many methods have been used to measure EBV-specific cellular immune responses. Previous studies have mainly used autologous EBV-transformed B-lymphoblastoid cell lines (B-LCLs), recombinant viral vectors transfected or peptide pulsed dendritic cells (DCs) as stimulators of CD8⁺ and CD4⁺ T lymphocytes. In the present study, we used an interferon-γ (IFN-γ) enzyme-linked immunospot (ELISPOT) assay by using isolated CD8⁺ and CD4⁺ T cells stimulated with mRNA-transfected DCs. The frequency of latent membrane protein 1 (LMP1)-specific IFN-γ producing CD4⁺ T cells was significantly higher than that of LMP2a. The frequency of IFN-γ producing CD4⁺ T cells was significantly correlated with that of CD8⁺ T cells in LMP1-specific immune responses (r = 0.7187, Pc < 0.0001). To determine whether there were changes in LMP1- or LMP2a-specific immune responses, subsequent peripheral blood mononuclear cells (PBMCs) samples were analyzed. Significant changes were observed in 5 of the 10 donors examined, and CD4⁺ T cell responses showed more significant changes than CD8⁺ T cell responses. CD8⁺ and CD4⁺ T cells from EBV-seropositive donors secreted only the Th1 cytokines IFN-γ, TNF-α, and IL-2, while Th2 (IL-4) and Th17 (IL-17a) cytokines were not detected. CD4⁺ T cells secreted significantly higher cytokine levels than did CD8⁺ T cells. Analysis of EBV-specific T cell responses using autologous DCs transfected with mRNA might provide a comprehensive tool for monitoring EBV infection and new insights into the pathogenesis of EBV-associated diseases.

Isotypes of Epstein-Barr virus antibodies in rheumatoid arthritis: association with rheumatoid factors and citrulline-dependent antibodies

In order to study the humoral immune response against Epstein-Barr virus (EBV) in patients with rheumatoid arthritis (RA) and to compare it with the two major autoantibody types in RA, plasma samples from 77 RA patients, 28 patients with systemic lupus erythematosus (SLE), and 28 healthy controls (HCs) were investigated by enzyme-linked immunosorbent assays (ELISA). Increased percentages of positives and concentrations of IgG/IgA/IgM antibodies against the latent EBV nuclear antigen-1 (EBNA-1) were observed in RA patients compared to SLE patients and HCs. Increased concentrations and percentages of positives of IgG/IgA/IgM against the early lytic EBV antigen diffuse (EAD) were also found in RA patients compared to HCs but were highest in SLE patients. Furthermore, associations between the elevated EBNA-1 IgA and EBNA-1 IgM levels and the presence of IgM and IgA rheumatoid factors (RFs) and anti-citrullinated protein antibodies (ACPAs, IgG) and between elevated IgA concentrations against EAD and the presence of RFs and ACPAs in RA patients were found. Thus, RA patients had elevated antibodies of all isotypes characteristic of latent EBV infection (whereas SLE patients had elevated antibodies characteristic of lytic EBV infection). Notably, for IgM and IgA (but not IgG), these were associated with the presence of characteristic RA autoantibodies.

Drug free remission after steroid-dependent disappearance of lymphoproliferative disorder in rheumatoid arthritis patient treated with TNF-alpha blockade: case study

Introduction

TNF-α inhibitors plus MTX appear to have benefit in the longer-term reduction of RA. Boolean long-term remission under drug-free conditions is rare. The therapeutic mechanism and the factor of predicting response have not been clarified yet.

Case description

A 24-year-old female rheumatoid arthritis (RA) patient, who once attained complete remission (CR) with the combination therapy with tumor necrosis factor alpha (TNF-alpha) inhibitor adalimumab (ADA) and methotrexate (MTX), showed the occurrence of Epstain- Barr virus (EBV)-associated lymphoproliferative disorder (LPD). Pulse treatment with methylprednisolone after the termination of anti TNF-α therapy resulted in the remission of EBV-associated LPD. The administration of prednisolone (PSL) was tapered off after the improvement of clinical symptoms and laboratory data. The patients achieved drug-free 12 months after urgent hospitalization and delivered healthy baby 2 years after hospital discharge. She has been complete drug-free Boolean remission for 5 years.

Discussion and evaluation

The purpose of this brief case is report that we experienced the remission of LPD after CR with combined therapy with ADA and MTX. We believe this case report will be one of the paths for unveiling the pathogenesis and improving the treatment for RA.

Conclusions

We believe this case report will be one of the paths for unveiling the pathogenesis and improving the treatment for RA.

Epstein-Barr virus effect on frequency of functionally distinct T cell subsets in children with infectious mononucleosis

PURPOSE

Epstein-Barr virus is a common human pathogen which infects the great majority of population worldwide. A striking proliferation of CD8⁺ T cells is an immune response to EBV invasion of B lymphocytes during infectious mononucleosis. The aim of the study was to analyze frequencies of CD28⁺CD95⁻, CD28⁺CD95⁺, CD28⁻CD95⁺ T cell subsets putative naïve (T(N)), central (T(CM)) and effector memory (T(EM)) T cells in children with infectious mononucleosis.

MATERIAL/METHODS

Multiparameter flow cytometric analysis of CD4⁺ and CD8⁺ T cell subsets was performed in 19 children with acute infectious mononucleosis.

RESULTS

The CD4⁺/CD8⁺ ratio was found to be decreased (0.53) in children with infectious mononucleosis. Median T(N), T(CM), T(EM) frequencies were estimated to be 3.7, 4.5, 15.1% of CD8⁺ and 23, 59.3, 5.5% of CD4⁺ T cells, respectively. In the present study we demonstrated negative correlations between CD8⁺CD28⁺CD95⁺ and CD8⁺CD28⁻CD95⁺ T cells and both VCA IgM antibody titers and disease duration. However, no such correlation was found when subset of CD4⁺ T cells or CD8⁺CD28⁺CD95⁻ cells was compared.

CONCLUSIONS

We conclude that there is a rapid decrease in the number of memory CD8⁺ T cells in early acute stage of infectious mononucleosis.

ERAP1 functions override the intrinsic selection of specific antigens as immunodominant peptides, thereby altering the potency of antigen-specific cytolytic and effector memory T-cell responses

Endoplasmic reticulum aminopeptidase 1 (ERAP1) is a critical component of the adaptive immune system that has been shown to increase or decrease the presentation of specific peptides on MHC class I molecules. Here, we have demonstrated that ERAP1 functions are not only important during the presentation of antigen-derived peptides, but these functions can also completely change which antigen-derived peptides ultimately become selected as immunodominant T-cell epitopes. Our results suggest that ERAP1 may do this by destroying epitopes that would otherwise become immunodominant in the absence of adequate ERAP1 functionality. We further establish that ERAP1-mediated influences on T-cell functions are both qualitative and quantitative, by demonstrating that loss of ERAP1 function redirects CTL killing toward a different set of antigen-derived epitopes and increases the percent of antigen-specific memory T cells elicited by antigen exposure. As a result, our studies suggest that normal ERAP1 activity can act to suppress the numbers of T effector memory cells that respond to a given antigen. This unique finding may shed light on why certain ERAP1 single nucleotide polymorphisms are associated with several autoimmune diseases, for example, by significantly altering the robustness and quality of CD8+ T-cell memory responses to antigen-derived peptides.

HLA and rheumatoid arthritis: how do they connect?

Rheumatoid arthritis (RA) is a destructive autoimmune disease that mainly affects synovial joints. RA patients can be subdivided in two distinct disease subsets based on the presence of anti-citrullinated protein antibodies (ACPA). These two disease phenotypes are associated with different environmental and genetic risk factors and clinical parameters. The HLA class II locus is the most important risk factor for ACPA-positive RA (ACPA+ RA). ACPA can be found up to 10 years before diagnosis and can be used as a predictive biomarker. During progression from breaking tolerance to a citrullinated protein to ACPA+ RA, the ACPA response matures. Recent work implicates the HLA class II locus as a risk factor in the progression from ACPA positivity to ACPA+ RA. We now propose that this locus directly influences the maturation of the ACPA response, most likely via antigen-specific T-cells providing help to ACPA-producing B-cells allowing for maturation of the citrullinated protein-specific autoantibody response. We present and discuss several models and underlying data, including antibody cross-reactivity, molecular mimicry, and neo-antigen formation, that could explain the HLA-RA connection.

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.

Adaptive immunity in rheumatic diseases: bystander or pathogenic player?

Rheumatic diseases comprise a wide spectrum of different conditions. Some are caused by disturbances of the adaptive immune system, while defects in innate immune responses have been identified for others. In between are a variety of multifactorial diseases for which the evidence for a causative involvement of the adaptive immune system is still controversial. In these cases, availability of novel drugs that target key players of the adaptive immune system have improved our understanding of the relevance of adaptive immunity to the disease process, but it has also generated unprecedented findings. Rheumatoid arthritis (RA) is a prototypic example of a disease in which the relative contribution of adaptive immunity to disease pathogenesis is incompletely understood. Although numerous markers have been identified that reflect an activated adaptive immune system, several caveats render interpretation of these findings difficult. For one, the very early immune responses initiating disease are likely to take place before an individual is identified as a patient, and are thus difficult to study in the human. Furthermore, increasing evidence points to pathogenetically distinct subgroups within the clinical diagnosis RA, offering the possibility that adaptive immune responses might be relevant to one subgroup but not the other. In addition, many indications for an adaptive immune system involvement are based on associations for which the underlying mechanism is often unknown. Finally, therapeutic interventions targeting the adaptive immune system have generated heterogeneous results. The present review addresses these issues by placing adaptive immune responses in the context of rheumatic diseases, and by reviewing the evidence for a contribution of adaptive immunity to RA.

Subclinical Epstein-Barr virus viremia among adult renal transplant recipients: incidence and consequences

The natural history and clinical significance of posttransplant Epstein-Barr virus (EBV) infection remain largely unknown. The aims of this study are to describe the incidence, risk factors and consequences of EBV infection after kidney transplantation. A total of 383 consecutive patients having received a kidney transplant between January 2002 and December 2010 were included. EBV polymerase chain reaction (PCR) was performed every 2 weeks for 3 months, and every 4 weeks for the next 9 months. A total of 155 of the 383 patients (40%) had at least one positive viremia during the first year posttransplant. The median time to viremia was day 31 posttransplant (14-329). A total of 73 (47%) had EBV viremia > 10(3) log and 23 (15%) had positive viremia for more than 6 months. EBV D+/R- patients (12/18 (67%) versus 143/365 (39%), p = 0.02) and those having received antithymocyte globulins (ATG) (54% vs. 35%; p<0.001) were more likely to develop EBV infection. EBV infection (hazard ratio [HR], 3.03; 95% confidence interval [CI], 1.72-8.29; p = 0.01) was associated with the occurrence of opportunistic infections. A positive EBV PCR during the first 6 months posttransplant was associated with graft loss (HR, 3.04; 95% CI, 1.36-6.79; p = 0.014). EBV reactivation is frequent after transplantation and reflects overimmunosuppression. Prospective studies should examine the association between EBV and graft loss.

Attenuated antigen-specific T cell responses in cirrhosis are accompanied by elevated serum interleukin-10 levels and down-regulation of HLA-DR on monocytes

BACKGROUND

Advanced liver disease predisposes to bacterial translocation and endotoxaemia which can contribute to elevated circulating levels of IL-10 and down-regulation of MHC class II on antigen-presenting cells. We sought to evaluate antigen-specific T-cell responses toward common viral antigens in order to investigate defects in cellular immunity in cirrhosis.

METHODS

Peripheral blood was obtained from 22 cirrhotic patients with systemic inflammation, 13 cirrhotic patients without systemic inflammation and 14 healthy controls. C-reactive protein was used as an indicator for systemic inflammation using a cut-off of 10 mg/l. Intracellular Th1 cytokines were quantified after T cell-stimulation with the viral peptides EBNA1 and BZLF1 or the bacterial superantigen SEB by flow cytometry. Serum levels of lipopolysaccharide-binding protein (LBP) and IL-10 were quantified by ELISA.

RESULTS

Compared to healthy controls, patients with cirrhosis had higher circulating levels of LBP and IL-10, an expansion of peripheral blood CD14+ monocytes with low HLA-DR expression and an increased fraction of CD25-positive CD4+ and CD8+ T cells. These findings were most pronounced in cirrhotic patients with systemic inflammation but fell short of reaching statistical significance when comparing against cirrhotic patients without systemic inflammation. In the former group TNF-α production in CD4+ and CD8+ T cells was reduced after stimulation with SEB, whereas there was no significant difference between the total cohort of cirrhotic patients and controls. After stimulation with the overlapping peptide pools for viral antigens EBNA1 and BZLF1, the number of responding T cells and the amount of TNF-α or IFN-γ production did not differ between the three pre-defined groups. However, cirrhotic patients with null-responses to EBV peptides had significantly higher serum IL-10 levels than responders to EBV peptides. Furthermore, TNF-α production in responding T cells was attenuated in patients with a high frequency of CD14+ HLA-DR- monocytes.

CONCLUSION

Our data suggest that bacterial translocation, endotoxaemia, inflammation and T cell activation in cirrhosis are accompanied by an increase in circulating anti-inflammatory cytokines, reduced monocytic MHC class II expression and attenuated cytokine production in T cells. These changes are likely to contribute to altered adaptive immune responses during infection or after vaccination.

Microbial Infection and Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a complex autoimmune disease affecting 1–2% of general worldwide population. The etiopathogenesis of RA involves the interplay of multiple genetic risk factors and environmental triggers. Microbial infections are believed to play an important role in the initiation and perpetuation of RA. Recent clinical studies have shown the association of microbial infections with RA. Accumulated studies using animal models have also found that microbial infections can induce and/or exaggerate the symptoms of experimental arthritis. In this review, we have identified the most common microbial infections associated with RA in the literature and summarized the current evidence supporting their pathogenic role in RA. We also discussed the potential mechanisms whereby infection may promote the development of RA, such as generation of neo-autoantigens, induction of loss of tolerance by molecular mimicry, and bystander activation of the immune system.

A profile of immune response to herpesvirus is associated with radiographic joint damage in rheumatoid arthritis

Introduction

Progression of joint damage despite appropriate therapy remains a significant problem for patients with rheumatoid arthritis (RA). This study was undertaken to identify profiles of immune response that correlate with radiographic joint damage as a first step toward the discovery of new pathogenic mechanisms of joint destruction in RA.

Methods

The study included 58 patients with RA and 15 healthy controls. The profiles of cytokine release from peripheral blood mononuclear cells (PBMC) in response to stimulation for 48 hours with one of six stimuli, or in media alone, were measured. Immune response profiles identified for each stimulus were correlated with radiographic joint damage as defined by the Sharp-van der Heijde score (SHS), before and after multivariable adjustment. For profiles correlated with the SHS, the distributions of individual cytokines were evaluated in patients according to the severity of joint damage and compared to healthy controls.

Results

The immune response profile for cytomegalovirus (CMV)/Epstein-Barr virus (EBV) stimulation was correlated with both the SHS total and erosion scores (r = 0.31, P = 0.018 and r = 0.33, P = 0.011, respectively). After adjusting for age, sex, disease duration, autoantibody status, CMV/EBV serological status, current disease activity, disability and treatments, the correlation of the CMV/EBV immune response and the SHS erosion score became stronger (r = 0.43, P < 0.003). The CMV/EBV immune response correlated with CMV IgG (r = 0.44, P < 0.001), but not with EBV IgG. The most important cytokines for the CMV/EBV immune response profile were IFN-γ, IL-2, IL-4, IL-5, IL-13 and IL-17A, all of which are associated with T-cell immunity. Both the summary immune response score and the individual responses of IFN-γ and IL-13 to CMV/EBV stimulation were associated with greater joint damage.

Conclusions

A profile of immune response to purified CMV/EBV lysates is associated with radiographic joint damage. The correlation of this immune response to CMV serology implies possible involvement of latent CMV infection. Therefore, the findings suggest that the immune response to latent CMV infection could play a fundamental role in the progression of inflammation and structural joint damage in patients with RA.

Summary of roundtable discussion meeting: non-human primates to assess risk for EBV-related lymphomas in humans

Epstein-Barr virus (EBV)-associated lymphomas are a known risk for immunosuppressed individuals. Non-clinical methods to determine the potential of new immunomodulatory compounds to produce EBV-associated lymphomas (hazard identification) have not been developed. Since lymphocryptovirus (LCV) in non-human primates (NHP) has similar characteristics to EBV in humans, a Roundtable meeting was held in October 2010 to explore how the potential for EBV-related lymphomas in humans can be assessed by using surrogate biomarkers for lymphoma risk in NHP toxicity studies. Stakeholders from regulatory agencies, academia, and industry came together to determine the research gaps and potential benefits and considerations of such an approach given the current state-of-the-science. Key conclusions from the discussion included considerations raised about the potential usefulness of LCV-related biomarkers from NHP studies since there is significant controversy over the reliability of using EBV viral load or EBV-specific T-lymphocytes to predict for lymphoproliferative disorders in transplant patients. In addition, there are technical challenges that need to be further addressed in order to develop methods to measure LCV viral load and LCV-specific T-lymphocytes from cynomolgus monkeys.

EBV-specific immune responses in patients with multiple sclerosis responding to IFNβ therapy

Background: Symptomatic primary infection with the human γ-herpesvirus Epstein–Barr virus (EBV) and elevated immune responses to EBV are associated with the development and progression of multiple sclerosis (MS). Interferon-beta (IFNβ), first-line treatment for relapse-onset MS, exhibits complex immunoregulatory and antiviral activities.

Objective: To determine EBV-specific immune responses in patients with MS during IFNβ therapy.

Methods: We evaluated cellular and humoral immune responses to EBV- and human cytomegalovirus (HCMV)-encoded antigens in patients with MS before and 1 year after IFNβ treatment by ELISA and flow cytometry. Twenty-eight patients with MS who showed a clinical response to IFNβ as defined by the absence of relapses and lack of progression on the Expanded Disability Status Scale score during the first 2 years of treatment were included.

Results: Clinically effective IFNβ-therapy was associated with a downregulation of proliferative T cell responses to the latent EBV nuclear antigen-1 (EBNA1). EBNA1-specific IgG responses as well as cellular and humoral immune responses to MHC class I restricted EBV antigens expressed during lytic replication and viral B cell transformation were similar before and after IFNβ therapy. Although HCMV-specific IgG levels slightly decreased, proliferative T-cell responses towards HCMV antigens remained unchanged during IFNβ therapy.

Conclusion: Clinically effective IFNβ therapy is associated with a reduction of proliferative T-cell responses to EBNA1.

Epstein-Barr virus induces erosive arthritis in humanized mice

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of rheumatoid arthritis (RA) on the basis of indirect evidence, such as its presence in affected joint tissues, antigenic cross reactions between EBV and human proteins, and elevated humoral and cellular anti-EBV immune responses in patients. Here we report development of erosive arthritis closely resembling RA in humanized mice inoculated with EBV. Human immune system components were reconstituted in mice of the NOD/Shi-scid/IL-2Rγ^null (NOG) strain by transplantation with CD34⁺ hematopoietic stem cells isolated from cord blood. These humanized mice were then inoculated with EBV and examined pathologically for the signs of arthritis. Erosive arthritis accompanied by synovial membrane proliferation, pannus formation, and bone marrow edema developed in fifteen of twenty-three NOG mice transplanted with human HSC and inoculated with EBV, but not in the nine NOG mice that were transplanted with HSC but not inoculated with EBV. This is the first report of an animal model of EBV-induced arthritis and strongly suggest a causative role of the virus in RA.

Elevated Epstein-Barr virus-encoded nuclear antigen-1 immune responses predict conversion to multiple sclerosis

OBJECTIVE

The aims of the study were to determine the immune responses to candidate viral triggers of multiple sclerosis (MS) in patients with clinically isolated syndromes (CISs), and to evaluate their potential value in predicting conversion to MS.

METHODS

Immune responses to Epstein-Barr virus (EBV), human herpesvirus 6, cytomegalovirus (HCMV), and measles were determined in a cohort of 147 CIS patients with a mean follow-up of 7 years and compared with 50 demographically matched controls.

RESULTS

Compared with controls, CIS patients showed increased humoral (p < 0.0001) and cellular (p = 0.007) immune responses to the EBV-encoded nuclear antigen-1 (EBNA1), but not to other EBV-derived proteins. Immunoglobulin G (IgG) responses to other virus antigens and frequencies of T cells specific for HCMV and influenza virus gene products were unchanged in CIS patients. EBNA1 was the only viral antigen with which immune responses correlated with number of T2 lesions (p = 0.006) and number of Barkhof criteria (p=0.001) at baseline, and with number of T2 lesions (p = 0.012 at both 1 and 5 years), presence of new T2 lesions (p = 0.003 and p = 0.028 at 1 and 5 years), and Expanded Disability Status Scale score (p = 0.015 and p = 0.010 at 1 and 5 years) during follow-up. In a univariate Cox regression model, increased EBNA1-specific IgG responses predicted conversion to MS based on McDonald criteria (hazard ratio [95% confidence interval], 2.2 [1.2-4.3]; p = 0.003).

INTERPRETATION

Our results indicate that elevated immune responses toward EBNA1 are selectively increased in CIS patients and suggest that EBNA1-specific IgG titers could be used as a prognostic marker for disease conversion and disability progression.

Development of a quantitative assay to measure EBV viral load in patients with autoimmune type 1 diabetes and healthy subjects

Clinical studies of immune modulating agents such as otelixizumab, an anti-CD3 monoclonal antibody that is being investigated as a possible treatment for type 1 diabetes, required a sensitive, specific, reproducible method of quantifying Epstein-Barr virus (EBV) load in healthy adults and in patients with conditions not generally associated with increased EBV levels. An assay was developed using a commercial kit and was fully validated. To enhance assay sensitivity and reproducibility, viral load was quantified per 10(6) peripheral blood mononuclear cells (PBMCs) rather than per ml blood. The lower limit of quantitation (LLQ) was approximately 1000 EBV copies per 10(6) PBMCs, while the effective LLQ of an assay using whole blood was 5000 EBV copies per ml blood. Based on results from 39 healthy subjects, a reference range of up to 10000 EBV copies per 10(6) PBMCs was established. Of 126 subjects with type 1 diabetes, none had viral loads greater than 10000 EBV copies per 10(6) PBMCs.

Immunization with an immunodominant self-peptide derived from glucose-6-phosphate isomerase induces arthritis in DBA/1 mice

Introduction

T-helper (Th) lymphocytes are critically required for the pathogenesis of glucose-6-phosphate isomerase (G6PI)-induced arthritis, but neither the G6PI epitopes recognized by arthritogenic T cells nor their pathogenic effector functions have been fully elucidated to date. We aimed at identifying arthritogenic G6PI peptides.

Methods

We used a library of overlapping peptides spanning the entire G6PI sequence to identify the epitopes recognized by G6PI-specific Th cells. Immunodominant peptides were then used to immunize mice. Arthritis development was evaluated clinically and histologically. The humoral and cellular immune responses upon peptide immunization were analyzed by ELISA and multiparameter flow cytometry, respectively.

Results

We identified six immunodominant T-cell epitopes in DBA/1 mice, of which three are arthritogenic. One of these peptides (G6PI_469–483) is identical in man and mice. Immunization with this peptide induces arthritis, which is less severe and of shorter duration than arthritis induced by immunization with full-length G6PI. Upon immunization with either G6PI or peptide, the antigen-specific Th cells produce IL-17, RANKL, IFNγ and TNFα.

Conclusions

We identified immunodominant and arthritogenic epitopes of G6PI. Not all immunodominant peptides are arthritogenic. This is the first description of arthritis induced by immunization with a self-peptide in mice.

Effect of methotrexate and anti-TNF on Epstein-Barr virus T-cell response and viral load in patients with rheumatoid arthritis or spondylarthropathies

INTRODUCTION

There is a suspicion of increased risk of Epstein-Barr virus (EBV)-associated lymphoproliferations in patients with inflammatory arthritides receiving immunosuppressive drugs. We investigated the EBV load and EBV-specific T-cell response in patients treated with methotrexate (MTX) or anti-TNF therapy.

METHODS

Data for patients with rheumatoid arthritis (RA) (n = 58) or spondylarthropathy (SpA) (n = 28) were analyzed at baseline in comparison with controls (n = 22) and after 3 months of MTX or anti-TNF therapy for EBV load and EBV-specific IFNgamma-producing T cells in response to EBV latent-cycle and lytic-cycle peptides.

RESULTS

The EBV load and the number of IFNgamma-producing T-cells after peptide stimulation were not significantly different between groups at baseline (P = 0.61 and P = 0.89, respectively). The EBV load was not significantly modified by treatment, for RA with MTX (P = 0.74) or anti-TNF therapy (P = 0.94) or for SpA with anti-TNF therapy (P = 1.00). The number of EBV-specific T cells was not significantly modified by treatment, for RA with MTX (P = 0.58) or anti-TNF drugs (P = 0.19) or for SpA with anti-TNF therapy (P = 0.39). For all patients, the EBV load and EBV-specific T cells were significantly correlated (P = 0.017; R = 0.21). For most patients, short-term exposure (3 months) to MTX or anti-TNF did not alter the EBV load or EBV-specific T-cell response but two patients had discordant evolution.

CONCLUSIONS

These data are reassuring and suggest there is no short-term defect in EBV-immune surveillance in patients receiving MTX or anti-TNF drugs. However, in these patients, long term follow-up of EBV-specific T-cell response is necessary and the role of non-EBV-related mechanisms of lymphomagenesis is not excluded.

Antiviral immune responses: triggers of or triggered by autoimmunity?

The predisposition of individuals to several common autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus and multiple sclerosis, is genetically linked to certain human MHC class II molecules and other immune modulators. However, genetic predisposition is only one risk factor for the development of these diseases, and low concordance rates in monozygotic twins, as well as the geographical distribution of disease risk, suggest the involvement of environmental factors in the development of these diseases. Among these environmental factors, infections have been implicated in the onset and/or promotion of autoimmunity. In this Review, we outline the mechanisms by which viral infection can trigger autoimmune disease and describe the pathways by which infection and immune control of infectious disease might be dysregulated during autoimmunity.