Synovial Epstein-Barr virus infection increases the risk of rheumatoid arthritis in individuals with the shared HLA-DR4 epitope

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

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

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.

The Role of Viral Infections in the Onset of Autoimmune Diseases

Autoimmune diseases (AIDs) are the consequence of a breach in immune tolerance, leading to the inability to sufficiently differentiate between self and non-self. Immune reactions that are targeted towards self-antigens can ultimately lead to the destruction of the host's cells and the development of autoimmune diseases. Although autoimmune disorders are comparatively rare, the worldwide incidence and prevalence is increasing, and they have major adverse implications for mortality and morbidity. Genetic and environmental factors are thought to be the major factors contributing to the development of autoimmunity. Viral infections are one of the environmental triggers that can lead to autoimmunity. Current research suggests that several mechanisms, such as molecular mimicry, epitope spreading, and bystander activation, can cause viral-induced autoimmunity. Here we describe the latest insights into the pathomechanisms of viral-induced autoimmune diseases and discuss recent findings on COVID-19 infections and the development of AIDs.

Are Viral Infections Key Inducers of Autoimmune Diseases? Focus on Epstein–Barr Virus

It is generally accepted that certain viral infections can trigger the development of autoimmune diseases. However, the exact mechanisms by which these viruses induce autoimmunity are still not understood. In this review, we first describe hypothetical mechanisms by which viruses induce some representative autoimmune diseases. Then, we focus on Epstein–Barr virus (EBV) and discuss its role in the pathogenesis of rheumatoid arthritis (RA). The discussion is mainly based on our own previous findings that (A) EBV DNA and its products EBV-encoded small RNA (EBER) and latent membrane protein 1 (LMP1) are present in the synovial lesions of RA, (B) mRNA expression of the signaling lymphocytic activation molecule-associated protein (SAP)/SH2D1A gene that plays a critical role in cellular immune responses to EBV is reduced in the peripheral T cells of patients with RA, and (C) EBV infection of mice reconstituted with human immune system components (humanized mice) induced erosive arthritis that is pathologically similar to RA. Additionally, environmental factors may contribute to EBV reactivation as follows: Porphyromonas gingivalis peptidylarginine deiminase (PAD), an enzyme required for citrullination, engenders antigens leading to the production of citrullinated peptides both in the gingiva and synovium. Anti-citrullinated peptides autoantibody is an important marker for diagnosis and disease activity of RA. These findings, as well as various results obtained by other researchers, strongly suggest that EBV is directly involved in the pathogenesis of RA, a typical autoimmune disease.

Interplay of Environmental, Individual and Genetic Factors in Rheumatoid Arthritis Provocation

In this review, we explore systemization of knowledge about the triggering effects of non-genetic factors in pathogenic mechanisms that contribute to the development of rheumatoid arthritis (RA). Possible mechanisms involving environmental and individual factors in RA pathogenesis were analyzed, namely, infections, mental stress, sleep deprivation ecology, age, perinatal and gender factors, eating habits, obesity and smoking. The non-genetic factors modulate basic processes in the body with the impact of these factors being non-specific, but these common challenges may be decisive for advancement of the disease in the predisposed body at risk for RA. The provocation of this particular disease is associated with the presence of congenital loci minoris resistentia. The more frequent non-genetic factors form tangles of interdependent relationships and, thereby, several interdependent external factors hit one vulnerable basic process at once, either provoking or reinforcing each other. Understanding the specific mechanisms by which environmental and individual factors impact an individual under RA risk in the preclinical stages can contribute to early disease diagnosis and, if the factor is modifiable, might be useful for the prevention or delay of its development.

The Effect of α7nAChR Signaling on T Cells and Macrophages and Their Clinical Implication in the Treatment of Rheumatic Diseases

Rheumatoid arthritis (RA) is one of the most common autoimmune disease and until now, the etiology and pathogenesis of RA is not fully understood, although dysregulation of immune cells is one of the leading cause of RA-related pathological changes. Based on current understanding, the priority of anti-rheumatic treatments is to restore immune homeostasis. There are several anti-rheumatic drugs with immunomodulatory effects available nowadays, but most of them have obvious safety or efficacy shortcomings. Therefore, the development of novel anti-rheumatic drugs is still in urgently needed. Cholinergic anti-inflammatory pathway (CAP) has been identified as an important aspect of the so-called neuro-immune regulation feedback, and the interaction between acetylcholine and alpha 7 nicotinic acetylcholine receptor (α7nAChR) serves as the foundation for this signaling. Consistent to its immunomodulatory functions, α7nAChR is extensively expressed by immune cells. Accordingly, CAP activation greatly affects the differentiation and function of α7nAChR-expressing immune cells. As a result, targeting α7nAChR will bring profound therapeutic impacts on the treatment of inflammatory diseases like RA. RA is widely recognized as a CD4+ T cells-driven disease. As a major component of innate immunity, macrophages also significantly contribute to RA-related immune abnormalities. Theoretically, manipulation of CAP in immune cells is a feasible way to treat RA. In this review, we summarized the roles of different T cells and macrophages subsets in the occurrence and progression of RA, and highlighted the immune consequences of CAP activation in these cells under RA circumstances. The in-depth discussion is supposed to inspire the development of novel cell-specific CAP-targeting anti-rheumatic regimens.

Epstein-Barr viral corneal stromal keratitis occurring during rheumatoid arthritis treatment: a case report

Background

A case of Epstein-Barr viral (EBV) corneal stromal keratitis during rheumatoid arthritis (RA) treatment is presented.

Case presentation

A 74-year-old female undergoing RA treatment was previously treated for bacterial corneal ulcer and herpetic keratitis and healed with antibiotic eye drops and topical anti-herpes ointment. At the first visit to our hospital, she presented with findings of monocular posterior interstitial keratitis with neovascularization mostly located in the inferior cornea with a corneal epithelial defect. The right eye showed no thinning of the corneal periphery and anterior uveitis. Her RA had subsided with oral steroid treatment, and infectious mononucleosis (IM) had not developed. EBV DNA could be detected in her corneal sample. After an extended but ineffective period to antibiotic treatment the corneal infiltrate responded rapidly to topical corticosteroids.

Conclusion

EBV can cause stromal keratitis without IM during treatment for RA.

Effect of Epstein-Barr Virus DNA on the Incidence and Severity of Arthritis in a Rheumatoid Arthritis Mouse Model

Objective

We recently demonstrated that EBV DNA is correlated with proinflammatory responses in mice and in rheumatoid arthritis (RA) patients; hence, we utilized an RA mouse model to examine whether EBV DNA enhances the risk and severity of arthritis and to assess its immunomodulatory effects.

Methods

C57BL/6J mice were treated with collagen (arthritis-inducing agent), EBV DNA 6 days before collagen, EBV DNA 15 days after collagen, Staphylococcus epidermidis DNA 6 days before collagen, EBV DNA alone, or water. Mice were then monitored for clinical signs and affected joints/footpads were histologically analysed. The relative concentration of IgG anti- chicken collagen antibodies and serum cytokine levels of IL-17A and IFNϒ were determined by ELISA. The number of cells co-expressing IL-17A and IFNϒ in joint histological sections was determined by immunofluorescence.

Results

The incidence of arthritis was significantly higher in mice that received EBV DNA prior to collagen compared to mice that only received collagen. Similarly, increased clinical scores, histological scores and paw thicknesses with a decreased gripping strength were observed in groups treated with EBV DNA and collagen. The relative concentration of IgG anti-chicken collagen antibodies was significantly increased in the group that received EBV DNA 6 days prior to collagen in comparison to the collagen receiving group. On the other hand, the highest number of cells co-expressing IFNϒ and IL-17A was observed in joints from mice that received both collagen and EBV DNA.

Conclusion

EBV DNA increases the incidence and severity of arthritis in a RA mouse model. Targeting mediators triggered by viral DNA may hence be a potential therapeutic avenue.

Human osteoclastogenesis in Epstein-Barr virus-induced erosive arthritis in humanized NOD/Shi-scid/IL-2Rγnull mice

Many human viruses, including Epstein-Barr virus (EBV), do not infect mice, which is challenging for biomedical research. We have previously reported that EBV infection induces erosive arthritis, which histologically resembles rheumatoid arthritis, in humanized NOD/Shi-scid/IL-2Rγ^null (hu-NOG) mice; however, the underlying mechanisms are not known. Osteoclast-like multinucleated cells were observed during bone erosion in this mouse model, and therefore, we aimed to determine whether the human or mouse immune system activated bone erosion and analyzed the characteristics and origin of the multinucleated cells in hu-NOG mice. Sections of the mice knee joint tissues were immunostained with anti-human antibodies against certain osteoclast markers, including cathepsin K and matrix metalloproteinase-9 (MMP-9). Multinucleated cells observed during bone erosion stained positively for human cathepsin K and MMP-9. These results indicate that human osteoclasts primarily induce erosive arthritis during EBV infections. Human osteoclast development from hematopoietic stem cells transplanted in hu-NOG mice remains unclear. To confirm their differentiation potential into human osteoclasts, we cultured bone marrow cells of EBV-infected hu-NOG mice and analyzed their characteristics. Multinucleated cells cultured from the bone marrow cells stained positive for human cathepsin K and human MMP-9, indicating that bone marrow cells of hu-NOG mice could differentiate from human osteoclast progenitor cells into human osteoclasts. These results indicate that the human immune response to EBV infection may induce human osteoclast activation and cause erosive arthritis in this mouse model. Moreover, this study is the first, to our knowledge, to demonstrate human osteoclastogenesis in humanized mice. We consider that this model is useful for studying associations of EBV infections with rheumatoid arthritis and human bone metabolism.

Altered Antibody Response to Epstein-Barr Virus in Patients With Rheumatoid Arthritis and Healthy Subjects Predisposed to the Disease. A Twin Study

Objectives: To study Epstein-Barr virus (EBV) antibody patterns in twin individuals with rheumatoid arthritis (RA) and their healthy co-twins, and to determine the heritability of antibody responses against the EBV encoded EBNA1 protein.

Methods: Isotypes of EBNA1 antibodies were measured in 137 RA affected- and 150 healthy twin pairs. We estimated the effect of RA and RA predisposition, anti-citrullinated antibodies (ACPA), IgM rheumatoid factor (RF), the shared epitope (SE) and the PTPN22-T allele (PTPN22) on the level of EBNA1 antibodies. We also determined the heritability of EBNA1 antibody levels.

Results: IgA-EBNA1 antibody levels were increased in twins from RA discordant twin pairs irrespective of RA, ACPA or IgM-RF status. The IgG-EBNA1 antibody level was elevated in healthy co-twins from RA discordant twin pairs but not in RA affected twins. The IgM-EBNA1 antibody level was elevated in both RA twins and their healthy co-twins. The effect of RA on the IgA-EBNA1 antibody level was reversed when SE was present and with no effect of PTPN22. The heritability of IgA-, IgG- and IgM-EBNA1 antibody level was 40.6, 65.5, and 54.3%, with no effect of environment shared by the twins.

Conclusion: EBNA1 antibody levels are distinctively different between patients with RA and healthy subjects but also between relatives of RA strongly predisposed to RA and healthy subjects. The high level of IgA EBNA1 antibodies associated with RA and a family predisposition to RA is attributable to both genetics incl. the shared epitope and environmental variation.

Physiologic Target, Molecular Evolution, and Pathogenic Functions of a Monoclonal Anti-Citrullinated Protein Antibody Obtained From a Patient With Rheumatoid Arthritis

OBJECTIVE

In plasma from a patient with rheumatoid arthritis (RA), we previously isolated a human monoclonal anti-citrullinated protein antibody (ACPA), CCP-Ab1, that recognizes various citrullinated antigens. In this study, we aimed to explore the physiologic target of CCP-Ab1 and the role of molecular evolution, through affinity maturation, of this ACPA in the onset and the exacerbation of RA.

METHODS

The target protein of CCP-Ab1 was identified in the plasma of a patient with RA and purified under native conditions. Germline-reverted (GL-rev) CCP-Ab1 was generated, and its reactivity was compared to that of mature CCP-Ab1. The functions of CCP-Ab1 and GL-rev CCP-Ab1 in the onset or exacerbation of autoimmune arthritis were analyzed using autoimmune arthritis-prone SKG mice.

RESULTS

CCP-Ab1 bound citrullinated fibrinogen under native conditions. In cultures with GL-rev CCP-Ab1, the binding affinity to citrullinated fibrinogen was drastically reduced (P < 0.05). The elements implicated in GL-rev CCP-Ab1 binding to a citrullinated peptide, cfc1-cyc, were almost identical to those implicated in CCP-Ab1 binding. In arthritis-prone SKG mice, CCP-Ab1, but not GL-rev CCP-Ab1, induced significant exacerbation of experimental arthritis (P < 0.05). Increased production of interleukin-6, both in the joint tissue and in the serum, was observed in SKG mice treated with CCP-Ab1 compared to those treated with GL-rev CCP-Ab1 (P < 0.05). Furthermore, the immune complex formed by CCP-Ab1 and fibrinogen was detected at higher concentrations in the synovial tissue of SKG mice administered CCP-Ab1 (P < 0.05 versus control treatment groups).

CONCLUSION

These data show that germline-encoded CCP-Ab1, which binds weakly to citrullinated fibrinogen, undergoes hypermutation through the activation of naive B cells by citrullinated peptides/proteins, thereby stimulating high reactivity to citrullinated fibrinogen. These findings deepen our understanding of the role of molecular evolution of ACPAs in the onset and exacerbation of RA.

Immune response in LPD during methotrexate administration (MTX-LPD) in rheumatoid arthritis patients

Methotrexate (MTX) is known as a first-line synthetic disease-modifying anti-rheumatic drug (DMARD) for the treatment of rheumatoid arthritis (RA). Although the risk of LPD development increases by RA inflammation itself, observation of spontaneous regression of LPD after MTX discontinuation lead to the theory of lymphomagenic role of MTX. In this review, we focused on the several immune response involved in LPD that developed under MTX administration in RA patients.

EBV and CMV viral load in rheumatoid arthritis and their role in associated Sjögren's syndrome

INTRODUCTION

The role of viral infections in the pathogenesis of autoimmune diseases has long been suggested, but little evidence is available.

OBJECTIVE

This study aimed to evaluate an association between EBV and CMV and the presence of rheumatoid arthritis and its association with Sjögren's Syndrome.

PATIENTS AND METHOD

A case-control study was performed with 227 patients divided in RA (n = 99), RA/SS (n = 20), and C (n = 128). Resting salivary flow rate and Schirmer's test were performed; minor salivary gland biopsy was indicated in the case of suspected Sjögren's syndrome. CMV and EBV viral loads were quantified in peripheral blood, and their presence in glandular tissue samples was evaluated by in situ hybridization (EBV) and immunohistochemistry (CMV).

RESULTS

EBV was more frequent in RA and RA/SS than in C (P < .000007). No correlation with clinical markers (P > .05) or between RA and RA/SS was found (P > .05). A higher number of EBV/DNA copies were found in RA (158.52 copies/μL) and RA/SS (99.24 copies/μL) (P = .739). EBV/DNA was associated with the Schirmer test (P = .0231). CMV was detected in one patient of the RA group. None of the viruses were detected in biopsies of minor salivary glands.

CONCLUSIONS

Detection of EBV/DNA in peripheral blood was associated with RA regardless of the presence of SS.

Chronic Chikungunya Arthritis and Rheumatoid Arthritis: What They Have in Common

Chikungunya virus (CHIKV) is a single-stranded RNA virus belonging to the family Togaviridae and genus Alphavirus that causes an acute febrile illness, chikungunya fever, which is transmitted to humans by Aedes species mosquitoes. During acute illness, patients have high fever, polyarthralgias or polyarthritis, maculopapular rash, headache, and myalgia that lasts for days to weeks. Following resolution of acute infection, a significant proportion of patients develop chronic chikungunya arthritis that can resemble rheumatoid arthritis. In this review, we first consider the historical background of infectious causes of inflammatory arthritis, and then the pathogenic and clinical manifestations of chronic chikungunya arthritis as a rheumatoid arthritis mimic. We believe that chronic chikungunya arthritis may be a postinfectious inflammatory process, and that an understanding of the parallels and differences between chronic chikungunya arthritis and rheumatoid arthritis may offer insights into better diagnosis and treatment of both diseases.

Toll-like receptor 7 regulates osteoclastogenesis in rheumatoid arthritis

This study aimed to determine the regulatory role of toll-like receptor 7 (TLR7) in receptor activator of nuclear factor kappa-B ligand (RANKL) production and osteoclast differentiation in rheumatoid arthritis (RA). In confocal microscopy, the co-expression of TLR7, CD55 and RANKL was determined in RA synovial fibroblasts. After RA synovial fibroblasts were treated with imiquimod, the RANKL gene expression and protein production were determined by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Osteoclastogenesis from peripheral blood CD14+ monocytes which were cultured with imiquimod was assessed by determining the numbers of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. The signal pathways mediating the TLR7-induced RANKL expression and osteoclastogenesis were analysed after inhibition of intracellular signal molecules and their phosphorylation. Imiquimod stimulated the expression of TLR7 and RANKL and production of RANKL in RA synovial fibroblasts, increasing the phosphorylation of TRAF6, IRF7, mitogen-activated protein kinases (MAPK), c-Jun and NFATc1. When CD14+ monocytes were cultured with imiquimod or co-cultured with imiquimod-pre-treated RA synovial fibroblasts, they were differentiated into TRAP+ multinucleated osteoclasts in the absence of RANKL. TLR7 activation-induced osteoclastogenesis in RA through direct induction of osteoclast differentiation from its precursors and up-regulation of RANKL production in RA synovial fibroblasts. Thus, the blockage of TLR7 pathway could be a promising therapeutic strategy for preventing bone destruction in RA.

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.

Epstein-Barr virus infection and variants of Epstein-Barr nuclear antigen-1 in synovial tissues of rheumatoid arthritis

Objective

The objective of the present study was to investigate Epstein-Barr virus (EBV) infection as an environmental factor for the development of rheumatoid arthritis (RA).

Methods

Synovial tissues were collected during surgery from 128 RA and 98 osteoarthritis (OA) patients. DNA was extracted from synovial tissues. The EBV gene was assessed by nested PCR for the amplification of EBV nuclear antigen-1 (EBNA-1). The nucleotide sequence of the PCR product was elucidated. HLA-DRB1 genotyping was also performed.

Results

EBV DNA was more frequently detected in the synovial tissues of RA patients (32.8%) than OA patients (15.3%) (p<0.01). The frequency of EBNA-1 variants did not significantly differ between RA and OA (RA: 17%, OA: 13%). The population with the HLA-DRB1 shared epitope (SE) was significantly higher in RA patients (70.3%) than in OA patients (44.9%) (p<0.001). In RA patients, the presence of EBV DNA was similar among SE-positive and -negative patients (SE-positive: 34.4%, -negative: 28.9%). The population with the EBNA-1 variant did not significantly differ between SE-positive and -negative patients (SE-positive: 12.9%, -negative: 27.3%).

Discussion

The present results indicate that EBV infection contributes to the onset of RA and chronic inflammation in synovial tissues. The frequency of EBNA-1 gene variants was low and not significantly different between RA and OA, suggesting that EBNA-1 gene variants are not a risk factor for RA. HLA-DRB1 with SE is a genetic risk factor for the development of RA. However, neither the presence of EBV nor EBNA-1 gene variants differed between SE-positive and -negative RA patients. Therefore, these two risk factors, SE and EBV, may be independent.

Conclusion

EBV infection may be an environmental risk factor for the development of RA, while nucleotide variants of EBNA-1 do not appear to contribute to its development.

JAK-inhibitor tofacitinib suppresses interferon alfa production by plasmacytoid dendritic cells and inhibits arthrogenic and antiviral effects of interferon alfa

Tofacitinib is an oral Janus kinase inhibitor that is effective for the treatment of rheumatoid arthritis and shows encouraging therapeutic effects in several other autoimmune diseases. A prominent adverse effect of tofacitinib therapy is the increased risk of viral infections. Despite its advanced stage of clinical development, the modes of action that mediate the beneficial and adverse effects of tofacitinib in autoimmune diseases remain unclear. Interferon alfa (IFNα) produced by plasmacytoid dendritic cells (PDCs) is critically involved in the pathogenesis of many systemic autoimmune diseases and in immunity to viral infections. Using in vitro culture models with human cells, we studied the effects of tofacitinib on PDC survival and IFNα production, and on arthrogenic and antiviral effects of IFNα. Tofacitinib inhibited the expression of antiapoptotic BCL-A1 and BCL-XL in human PDC and induced PDC apoptosis. TLR7 stimulation upregulated the levels of antiapoptotic Bcl-2 family members and prevented the induction of PDC apoptosis by tofacitinib. However, tofacitinib robustly inhibited the production of IFNα by toll like receptor-stimulated PDC. In addition, tofacitinib profoundly suppressed IFNα-induced upregulation of TLR3 on synovial fibroblasts, thereby inhibiting their cytokine and protease production in response to TLR3 ligation. Finally, tofacitinib counteracted the suppressive effects of IFNα on viral replication. Tofacitinib inhibits PDC survival and IFNα production and suppresses arthrogenic and antiviral effects of IFNα signaling. Inhibition of the IFNα pathway at 2 levels may contribute to the beneficial effects of tofacitinib in autoimmune diseases and explain the increased viral infection rates observed during tofacitinib treatment.

Low levels of antibodies against common viruses associate with anti-citrullinated protein antibody-positive rheumatoid arthritis; implications for disease aetiology

BACKGROUND

Infection by common viruses has long been discussed in the aetiology of a number of autoimmune diseases, including rheumatoid arthritis (RA). However, studies investigating this hypothesis in RA show conflicting results. These studies often lack well-matched control populations, and many do not include data on autoantibodies, genetic risk factors and other environmental factors, which are known to contribute to disease only in subgroups of patients. In the present study, we have therefore examined the role of Epstein-Barr virus (EBV), cytomegalovirus (CMV) and parvovirus B19 (B19) in RA aetiology, by analysing anti-viral antibodies in relation to anti-citrullinated protein antibodies (ACPA), smoking, HLA-DRB1 shared epitope (SE) alleles, and clinical parameters, in both RA patients and matched controls.

METHODS

Anti-viral antibodies were measured by ELISA in serum samples from 990 RA patients and 700 controls from the Swedish population-based Epidemiological Investigation of RA (EIRA) cohort. Data on ACPA, smoking, SE, inflammation (C-reactive protein) and disease activity score in 28 joints (DAS28) was obtained from the EIRA database. Fisher's exact test, the chi-squared test, and the Mann-Whitney U test were used to calculate differences in anti-viral antibody frequencies and levels; unconditional logistic regression was used to determine the association of anti-viral antibodies with different RA subsets.

RESULTS

Antibodies against all viruses were highly prevalent in EIRA, with no major differences detected between ACPA-positive RA, ACPA-negative RA and controls. However, both anti-B19 and anti-EBV IgG levels were significantly lower in ACPA-positive RA compared to controls, and there were significant interactions between low levels of anti-B19 and anti-EBV antibodies and SE in the development of ACPA-positive RA.

CONCLUSION

We could not detect an association between RA and elevated anti-viral antibody levels, for any of the three common viruses, EBV, CMV or B19. On the contrary, our study demonstrated association between low anti-EBV/anti-B19 antibody levels and ACPA-positive RA, in particular when HLA-DRB1 SE was present. These data could potentially suggest that high anti-viral antibody levels would be protective against ACPA-positive RA. Further investigations are required to address the mechanisms behind these findings.

Epstein-Barr virus and rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases, with a 0.5% worldwide prevalence. The cause of RA remains unknown, however both genetic and environmental factors may contribute to its development. Among these is the Epstein-Barr virus (EBV). Here, we discuss several aspects of the close relationship between EBV and RA. Patients with RA have impaired control of EBV infection. Indeed, they have high titres of antibodies against EBV antigens. Their peripheral blood T lymphocytes are less efficient at controlling the outgrowth of EBV-infected B cells. RA patients have more EBV-infected B cells than normal controls, leading to a 10-fold systemic EBV overload. Post-transplant lymphoproliferative disorder (PTLPD) is a polyclonal EBV-positive B lymphocyte proliferation, which can evolve into an EBV-positive B cell lymphoma. RA patients also have an increased risk of developing EBV-associated lymphoproliferative disorder (LPD). Hence the need to monitor EBV load when treating RA patients with immunosuppressors. EBV, a widespread virus, highly recognized by antibodies but never eliminated, is an ideal candidate to trigger chronic immune complex disease. Anti-EBV antibody responses should be considered as one of the chronic autoantibody responses linked to the development of RA, in the same way as anti-citrullinated protein antibodies.

Historical observations contributing insights on etiopathogenesis of rheumatoid arthritis and role of rheumatoid factor

When studies on rheumatoid arthritis (RA) that were made many decades ago and could be considered "historical" in nature are analyzed in the context of recent observations, important insights on RA and on the function of rheumatoid factor (RF) become apparent. RF in the role of antibody to immune complexes (ICs) appears to be involved in activation of the complement system and in the production of chemotactic and inflammatory mediators, creating a condition that can be sustained and reinitiated. In the synovial cavity, a state of nonresolving inflammation is produced with the formation of citrullinated protein antigen-antibody complexes or other forms of ICs. This is followed by a second wave of IC production in the form of RF acting as antibody reactive with the initial ICs. Both of these processes are associated with complement consumption and production of inflammatory mediators. We present a model of an initiation phase of RA that might represent an example of repetitive formation of ICs and complement-mediated inflammation. Targeting therapy at this phase of RA to break the cycles of recurrent inflammation might be a novel approach to aid in further control of the disease.

How Rheumatoid Arthritis Can Result from Provocation of the Immune System by Microorganisms and Viruses

The pathogenesis of rheumatoid arthritis (RA), similar to development of a majority of inflammatory and autoimmune disorders, is largely due to an inappropriate or inadequate immune response to environmental challenges. Among these challenges, infectious agents are the undisputed leaders. Since the 1870s, an impressive list of microorganisms suspected of provoking RA has formed, and the list is still growing. Although a definite causative link between a specific infectious agent and the disease has not been established, several arguments support such a possibility. First, in the absence of a defined pathogen, the spectrum of triggering agents may include polymicrobial communities or the cumulative effect of several bacterial/viral factors. Second, the range of infectious episodes (i.e., clinical manifestations caused by pathogens) may vary in the process of RA development from preclinical to late-stage disease. Third, infectious agents might not trigger RA in all cases, but trigger it in a certain subset of the cases, or the disease onset may arise from an unfortunate combination of infections along with, for example, psychological stress and/or chronic joint tissue microtrauma. Fourth, genetic differences may have a role in the disease onset. In this review, two aspects of the problem of “microorganisms and RA” are debated. First, is there an acquired immune deficiency and, in turn, susceptibility to infections in RA patients due to the too frequent and too lengthy infections, which at last break the tolerance of self antigens? Or, second, is there a congenital deficiency in tolerance and inflammation control, which may occur even with ordinary infection frequency and duration?

Antibodies directed against endogenous and exogenous citrullinated antigens pre-date the onset of rheumatoid arthritis

BACKGROUND

Anti-citrullinated-peptide antibodies (ACPA) have been detected in individuals with developing rheumatoid arthritis (RA) before the onset of symptom, with an initially limited spectrum of reactivities that gradually broadens. The aim was to analyze the evolution of ACPA response pre-dating symptom onset, using four selected citrullinated exogenous and endogenous antigens.

METHODS

A cohort of 521 individuals sampled before symptoms of RA appeared and 272 population controls were identified from the Biobank of Northern Sweden; 241 samples from patients with early RA were also collected. ACPA were detected by ELISA on viral citrullinated peptides (VCP) derived from Epstein-Barr-virus nuclear antigen (EBNA)1 and EBNA2 (VCP1 and VCP2) and histone-4-derived citrullinated peptides (HCP1 and HCP2).

RESULTS

In pre-symptomatic individuals vs. patients with early RA, anti-VCP1 antibodies were detected in 10.4 % vs. 36.1 %, anti-VCP2 in 17.1 % vs. 52.3 %, anti-HCP1 in 10.2 % vs. 37.3 %, and anti-HCP2 in 16.3 % vs. 48.5 %, respectively. Anti-VCP and anti-HCP concentrations were significantly increased in pre-symptomatic individuals vs. controls (p < 0.001) and were increased approaching symptom onset. Anti-VCP and anti-HCP appeared simultaneously (median (IQR) 5.3 (6) years before symptom onset) and in combination yielded a high-risk ratio for disease development (OR = 8.0-18.9). Anti-VCP2 and anti-HCP2 antibodies were associated with HLA-DRB1*0401 in pre-symptomatic individuals. Three peptidylarginine deiminase (PAD)I3/PADI4 single nucleotide polymorphisms (SNPs) were significantly associated with anti-HCP1.

CONCLUSIONS

Anti-VCP and anti-HCP antibodies pre-date symptom onset and predict disease development, but no hierarchy of citrullinated epitopes can be identified. These results suggest that no inciting citrullinated antigen so far described is common to all patients with RA. The association between PADI3/PADI4 polymorphism and anti-HCP1 antibodies suggests a novel link between deimination and production of ACPA.

Toll-like receptors and chronic inflammation in rheumatic diseases: new developments

In the past few years, new developments have been reported on the role of Toll-like receptors (TLRs) in chronic inflammation in rheumatic diseases. The inhibitory function of TLR10 has been demonstrated. Receptors that enhance the function of TLRs, and several TLR inhibitors, have been identified. In addition, the role of the microbiome and TLRs in the onset of rheumatic diseases has been reported. We review novel insights on the role of TLRs in several inflammatory joint diseases, including rheumatoid arthritis, systemic lupus erythematosus, gout and Lyme arthritis, with a focus on the signalling mechanisms mediated by the Toll-IL-1 receptor (TIR) domain, the exogenous and endogenous ligands of TLRs, and the current and future therapeutic strategies to target TLR signalling in rheumatic diseases.

The Autoimmune Ecology

Autoimmune diseases (ADs) represent a heterogeneous group of disorders that affect specific target organs or multiple organ systems. These conditions share common immunopathogenic mechanisms (i.e., the autoimmune tautology), which explain the clinical similarities they have among them as well as their familial clustering (i.e., coaggregation). As part of the autoimmune tautology, the influence of environmental exposure on the risk of developing ADs is paramount (i.e., the autoimmune ecology). In fact, environment, more than genetics, shapes immune system. Autoimmune ecology is akin to exposome, that is all the exposures - internal and external - across the lifespan, interacting with hereditary factors (both genetics and epigenetics) to favor or protect against autoimmunity and its outcomes. Herein, we provide an overview of the autoimmune ecology, focusing on the immune response to environmental agents in general, and microbiota, cigarette smoking, alcohol and coffee consumption, socioeconomic status (SES), gender and sex hormones, vitamin D, organic solvents, and vaccines in particular. Inclusion of the autoimmune ecology in disease etiology and health will improve the way personalized medicine is currently conceived and applied.

Toll/Interleukin-1 Receptor Domain Derived from TcpC (TIR-TcpC) Ameliorates Experimental Autoimmune Arthritis by Down-modulating Th17 Cell Response

Evasion through immunomodulation is one of the several strategies adopted by pathogens to prolong their survival within the host. One such pathogen, Escherichia coli CFT073, utilizes an immunomodulatory protein, TcpC, to combat the host's innate immune defense. TcpC abrogates the function of MyD88 in macrophages, thus perturbing all the signaling processes that involve this adaptor protein. Although central to various signaling pathways initiated by IL-1, IL-18, and toll-like receptors, the precise contribution of MyD88 to the development of autoimmunity, particularly rheumatoid arthritis, still needs extensive exploration. Herein, by using the toll/interleukin-1 receptor (TIR) domain homologous C-terminal motif of TcpC, i.e. TIR-TcpC, we found MyD88 to be critical for the induction and progression of rheumatoid arthritis through its pivotal role in the development of Th17 cells, the subset of CD4(+) T-cells widely implicated in various autoimmune disorders. The TIR-TcpC mediated inhibition of signaling through MyD88, and subsequent amelioration of experimental autoimmune arthritis was observed to be an outcome of perturbations in the NFκB-RORγt (RAR-related orphan receptor γt) axis.

Detection of Epstein-Barr virus in synovial fluid of rheumatoid arthritis patients

INTRODUCTION

Rheumatoid arthritis (RA) is one of the most common chronic inflammatory disorders. Genes and environmental factors contribute to RA. Epstein-Barr Virus (EBV) has been considered as one the RA pathogeneses. The aim of this study was to detect of the EBV genome in patients with RA.

METHODS

In this cross-sectional study, 50 samples of synovial fluid were obtained from patients with RA from 2010-2012. Using a standard of the EBV genome and EBNA-1-specific primers, the method of PCR was set up. Then, all of the samples of synovial fluids separately were subjected to DNA extraction and Polymerase Chain Reaction (PCR) amplification. Data were analyzed using SPSS version 18.0. The statistical analysis was performed by the t-test.

RESULTS

The demographic and laboratory characteristic assay revealed that the mean age of patients was 49, and the patients were 60% males and 40% females. In addition, in all cases, the mean rheumatoid factor (RF) levels of the patients were below the normal level. The results of this study showed that the PCR was able to detect EBV DNA in > 60% of the cases.

CONCLUSION

The results of this study indicated that EBV was frequently detected in the synovial fluid of RA patients. Thus, EBV may be a strong candidate that can act at several levels of the pathophysiology of RA. However, these findings also indicated that EBV may play a role in the pathogenesis of RA. However, the possible relationship between RA and EBV must be determined by further research.

Monoclonal antibody against citrullinated peptides obtained from rheumatoid arthritis patients reacts with numerous citrullinated microbial and food proteins

OBJECTIVE

To investigate the reactivity of monoclonal anti-citrullinated protein antibody (ACPA) obtained from peripheral blood B cells of rheumatoid arthritis (RA) patients with human autoantigens as well as environmental proteins by determining the essential epitope for the ACPA.

METHODS

A human monoclonal ACPA (cyclic citrullinated peptide antibody 1 [CCP-Ab1]) was obtained by screening peripheral blood lymphocytes from 31 patients with RA using a novel monoclonal antibody-secreting cell (ASC) screening system, the immunospot-array assay on a chip. The essential epitope for CCP-Ab1 was determined using epitope mapping. Then, human, microbial, and plant proteins that share the essential epitope identified were searched using BLAST. Finally, representative proteins identified by the search were produced in vitro, and their reactivity with CCP-Ab1 was examined.

RESULTS

CCP-Ab1 bound CCP in a citrulline-indispensable manner. In CCP, the 6 amino acid residues required for CCP-Ab1 binding were identified. In the BLAST search, 38 human, 56 viral, 1,383 fungal, 547 bacterial, and 1,072 plant proteins were found to share the essential epitope, and CCP-Ab1 reacted with all of the recombinant citrullinated proteins tested, which included the various environmental factors, such as various plant proteins that are part of the daily diet.

CONCLUSION

Our findings demonstrate, for the first time, that a monoclonal ACPA (CCP-Ab1) derived from RA patients cross-reacts not only with various autoantigens but also with numerous plant and microbial proteins. We propose that countless environmental factors, including microbes and diet, may trigger the generation of ACPAs that then cross-react with various citrullinated human autoantigens through molecular mimicry to induce RA.

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.

Epstein-Barr virus infection transforms CD25+ B cells into antibody-secreting cells in rheumatoid arthritis patients

Epstein-Barr virus (EBV) infection may initiate production of autoantibodies and development of cancer and autoimmune diseases. Here we outline phenotypic and functional changes in B cells of patients with rheumatoid arthritis (RA) related to EBV infection. The B-cell phenotype was analysed in blood and bone marrow (BM) of RA patients who had EBV transcripts in BM (EBV(+) , n = 13) and in EBV(-) (n = 22) patients with RA. The functional effect of EBV was studied in the sorted CD25(+) and CD25(-) peripheral B cells of RA patients (n = 18) and healthy controls (n = 9). Rituximab treatment results in enrichment of CD25(+) B cells in peripheral blood (PB) of EBV(+) RA patients. The CD25(+) B-cell subset displayed a more mature phenotype accumulating IgG-expressing cells. It was also enriched with CD27(+) and CD95(+) cells in PB and BM. EBV stimulation of the sorted CD25(+) B cells in vitro induced a polyclonal IgG and IgM secretion in RA patients, while CD25(+) B cells of healthy subjects did not respond to EBV stimulation. CD25(+) B cells were enriched in PB and synovial fluid of RA patients. EBV infection affects the B-cell phenotype in RA patients by increasing the CD25(+) subset and by inducing their immunoglobulin production. These findings clearly link CD25(+) B cells to the EBV-dependent sequence of reactions in the pathogenesis of RA.

IL-29 enhances Toll-like receptor-mediated IL-6 and IL-8 production by the synovial fibroblasts from rheumatoid arthritis patients

INTRODUCTION

We previously reported that IL-29, a newly described member of interferon (IFN) family, was overexpressed in blood and synovium of rheumatoid arthritis (RA) patients and triggered proinflammatory cytokine IL-6 and IL-8 mRNA expression in RA synovial fibroblasts (RA-FLS). This suggests that IL-29 has an important role in synovial inflammation. Toll-like receptors (TLRs) also activate RA-FLS to produce inflammatory mediators including tumor necrosis factor α (TNF-α) and IL-1β in RA-FLS. Since the TLR family plays an early role in the innate immune response and the subsequent induction of the adaptive immune response, we hypothesize that IL-29 interacts with TLRs in RA inflammation. This study aimed to investigate the effect of IL-29 on TLR-mediated proinflammatory cytokine production in RA-FLS.

METHODS

The mRNA level of IL-29 receptors (IL-28Rα and IL-10R2) in RA-FLS was determined by semi-quantitative RT- PCR. IL-6 and IL-8 mRNA expressions in RA-FLS were evaluated by real-time PCR after pre-incubation with IL-29 and subsequent stimulation with peptidoglycan (PGN, TLR2 ligand), or polycytidylic acid (poly(I:C), TLR3 ligand), or lipopolysaccharide (LPS, TLR4 ligand) . The production of TLR2, 3, and 4 in RA-FLS after IL-29 stimulation was also assessed by real-time PCR and flow cytometry. IL-29 mRNA and protein expression in RA-FLS after stimulation with PGN, poly(I:C), or LPS were measured by real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS

The IL-29 receptor complex (IL-28Rα and IL-10R2) was identified in RA-FLS. IL-29 enhanced TLR-mediated IL-6 and IL-8 expression in RA-FLS. IL-29 upregulated expression of TLR2, 3 and 4 in RA-FLS. Exposure to PGN, poly(I:C) or LPS triggered IL-29 production by RA-FLS.

CONCLUSIONS

We show for the first time that IL-29 enhances TLR-induced proinflammatory cytokine production in RA-FLS via upregulation of TLRs.

Epstein-Barr virus in systemic autoimmune diseases

Systemic autoimmune diseases (SADs) are a group of connective tissue diseases with diverse, yet overlapping, symptoms and autoantibody development. The etiology behind SADs is not fully elucidated, but a number of genetic and environmental factors are known to influence the incidence of SADs. Recent findings link dysregulation of Epstein-Barr virus (EBV) with SAD development. EBV causes a persistent infection with a tight latency programme in memory B-cells, which enables evasion of the immune defence. A number of immune escape mechanisms and immune-modulating proteins have been described for EBV. These immune modulating functions make EBV a good candidate for initiation of autoimmune diseases and exacerbation of disease progression. This review focuses on systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and Sjögren's syndrome (SS) and sum up the existing data linking EBV with these diseases including elevated titres of EBV antibodies, reduced T-cell defence against EBV, and elevated EBV viral load. Together, these data suggest that uncontrolled EBV infection can develop diverse autoreactivities in genetic susceptible individuals with different manifestations depending on the genetic background and the site of reactivation.

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.

What is causing my arthritis, doctor? A glimpse beyond the usual suspects in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is a common, but heterogeneous, disease. Usually, when it comes to the pathogenesis of RA the physician faces a complex network of cytokines and cells of the immune system-the so-called effector level. However, is this network 'the cause' of the disease? Or is this rather the level most physicians are somewhat familiar with, as modern anti-rheumatic medications are having their targets there? In this review, we are looking beyond the usual culprits from the physician's perspective and discuss how other factors, such as genes, epigenetics, environmental factors, local joint characteristics or processes of aging might influence the clinical phenomenon RA.

Effect of anti-rheumatic agents on periodontal parameters and biomarkers of inflammation: a systematic review and meta-analysis

PURPOSE

Anti-rheumatic agents target common molecular pathways of inflammation in rheumatoid arthritis (RA) and periodontitis. The purpose of this study was to determine the relative effect of anti-rheumatic agents on the levels of inflammatory biomarkers and periodontal inflammation in RA patients with periodontitis.

METHODS

A systematic review and meta-analysis were conducted of studies comparing periodontal parameters of inflammation, such as bleeding on probing, and biomarkers of inflammation in RA patients with periodontitis and healthy adults with and without periodontitis. The search included the electronic databases MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar, inclusive through October 2011, with no language restrictions. Hand searches were conducted of the bibliographies of related journals and systematic reviews. Observational and interventional studies assessing the effects of antirheumatic therapy qualified for inclusion. Two reviewers performed independent data extraction and risk-of-bias assessment. Of the 187 identified publications, 13 studies fulfilled the inclusion criteria.

RESULTS

When compared to healthy adults without periodontitis, RA subjects were found to have significantly higher levels of bleeding on probing and limited evidence of higher levels of interleukin-1β and tumor necrosis factor-α (TNF-α) in gingival crevicular fluid and saliva. No consistent differences were found in periodontal parameters and inflammatory biomarkers between RA subjects and adults with periodontitis. Studies evaluating the effect of anti-TNF-α therapy in RA subjects with periodontitis have yielded inconsistent results.

CONCLUSIONS

There are limited data, however, to suggest that anti-TNF-α agents can reduce local production of inflammatory cytokines and periodontal inflammation in RA patients with periodontitis.

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.

TLR-dependent T cell activation in autoimmunity

Autoimmune disease can develop as a result of a breakdown in immunological tolerance, leading to the activation of self-reactive T cells. There is an established link between infection and human autoimmune diseases. Furthermore, experimental autoimmune diseases can be induced by autoantigens that are administered together with complete Freund's adjuvant, which contains killed Mycobacterium tuberculosis; in some cases, these bacteria can be replaced by individual pathogen-associated molecular patterns (PAMPs). Exogenous PAMPs and endogenous danger signals from necrotic cells bind to pattern recognition receptors (including Toll-like receptors) and activate signalling pathways in innate immune cells and in T cells. This leads to pro-inflammatory cytokine production and T cell activation, which are now considered to be major factors in the development of autoimmunity.

Epstein-Barr virus serologic abnormalities and risk of rheumatoid arthritis among women

BACKGROUND

Epstein-Barr virus (EBV) infection and the immune response may be involved in the pathogenesis of rheumatoid arthritis (RA). Past studies have suggested an association between EBV and RA.

METHODS

We studied the association between EBV serologies and RA risk in a nested case-control study in the Nurses' Health Study (NHS) cohorts. We confirmed incident RA cases from 1990 to 2002 by questionnaire and medical record review. Each incident case with blood collected prior to RA symptoms was matched with a healthy participant by time of day and date of blood collection, birth year, menopausal status and postmenopausal hormone use. Immunofluorescence assays measured serologic EBV responses: viral capsid antigen, early-antigen-diffuse and early antigen-complex (restricted and diffuse), Epstein Barr nuclear antigen (EBNA)-1, EBNA-2 and cytomegalovirus (CMV), as control. All were reported as titers, except CMV, which was reported as positive or negative. Antinuclear antibody positive samples were excluded. Elevated EBV antibody titers were defined as the upper 20% (or nearest titer) among controls. Conditional logistic regression analyses modeled RA risk associated with elevated EBV titers or the presence/absence of CMV, further adjusted for pack-years smoking and alcohol intake.

RESULTS

Eighty-seven incident RA cases were identified. Mean time to RA after blood draw was 6.2 (± 3.5) years in NHS and 1.9 (± 0.6) years in NHS II. Antibody titers against EBV were not significantly different between pre-RA cases and controls.

CONCLUSIONS

In this prospective study of women, we observed no association between EBV serologies and RA risk.

Epigenetic dysregulation of epstein-barr virus latency and development of autoimmune disease

Epstein-Barr virus (EBV) is ahumanherpesvirus thatpersists in the memory B-cells of the majority of the world population in a latent form. Primary EBV infection is asymptomatic or causes a self-limiting disease, infectious mononucleosis. Virus latency is associated with a wide variety of neoplasms whereof some occur in immune suppressed individuals. Virus production does not occur in strict latency. The expression of latent viral oncoproteins and nontranslated RNAs is under epigenetic control via DNA methylation and histone modifications that results either in a complete silencing of the EBV genome in memory B cells, or in a cell-type dependent usage of a couple of latency promoters in tumor cells, germinal center B cells and lymphoblastoid cells (LCL, transformed by EBV in vitro). Both, latent and lytic EBV proteins elicit a strong immune response. In immune suppressed and infectious mononucleosis patients, an increased viral load can be detected in the blood. Enhanced lytic replication may result in new infection- and transformation-events and thus is a risk factor both for malignant transformation and the development of autoimmune diseases. An increased viral load or a changed presentation of a subset of lytic or latent EBV proteins that cross-react with cellular antigens may trigger pathogenic processes through molecular mimicry that result in multiple sclerosis (MS), systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

A prospective approach to investigating the natural history of preclinical rheumatoid arthritis (RA) using first-degree relatives of probands with RA

OBJECTIVE

To describe a large, multicenter prospective cohort study of first-degree relatives (FDRs) of probands with rheumatoid arthritis (RA), and outline the use of such a study in investigating the natural history of RA development.

METHODS

A total of 1,058 FDRs, none of whom met the American College of Rheumatology criteria for RA, were enrolled in a prospective study investigating genetic and environmental influences on the development of RA-related autoimmunity. Demographic, epidemiologic, genetic, autoantibody, and physical examination data from the initial study enrollment visit were described for these FDRs, and the relationship was examined between genetic factors, autoantibodies, inflammation, and joint disease.

RESULTS

Fifty-five percent of the FDRs had > or =1 copy of the shared epitope, 20% had > or =1 copy of the PTPN22 polymorphism, and approximately 16% were positive for rheumatoid factor (RF; including isotypes) and/or anti-cyclic citrullinated peptide antibody. IgM-RF positivity is associated with > or =1 tender joint on examination (odds ratio [OR] 2.50, 95% confidence interval [95% CI] 1.27-4.89; P < 0.01) and elevated C-reactive protein (CRP) levels (OR 5.31, 95% CI 1.45-19.52; P = 0.01).

CONCLUSION

FDRs without RA demonstrate high prevalences of genetic risk factors and RA-related autoantibodies. Additionally, an RF association with tender joints and elevated CRP levels suggests that autoantibodies are a valid intermediate marker of RA-related autoimmunity in this cohort. This prospective FDR cohort will be a valuable resource for evaluating the relationship between genetic and epidemiologic factors and the development of RA-related autoimmunity.

Epstein-Barr-Virus-Infected CD15 (Lewis X)-Positive Hodgkin-Lymphoma-Like B Cells in Patients with Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA), especially those who are treated with methotrexate (MTX), might have an increased risk of Hodgkin lymphoma (HL), a malignancy that is associated with Epstein-Barr virus (EBV). Here we describe a monoclonal EBV-infected B-lymphoblastoid cell line (LCL) called TKS-1 that was established from cells that spontaneously converted from an MTX-treated RA patient. TKS-1 has properties similar to HL cells and it is distinctly different from control LCLs established from normal individuals. TKS-1 cells express the HL -associated surface markers CD15 and CD30 (Takei et al. 1989). Like Hodgkin Reed-Sternberg (H-RS) cells of EBV-positive HL, TKS-1 cells express EBNA1 mRNA transcribed from the Qp promoter of the virus, whereas control LCLs use the Cp or Wp promoter to transcribe mRNA. TKS-1 cells can proliferate in an anchorage-independent manner and possess a cloning efficiency comparable to that of the Burkitt lymphoma (BL) line Raji. In addition, two EBV-positive LCLs established by cocultivated CD34+ cells isolated from the bone marrow of patients with RA and peripheral blood B lymphocytes from a healthy EBV-seronegative individual also expressed CD15. These results indicate that EBV-infected B-lymphoblastoid cells from patients with RA tend to acquire properties similar to HL cells.

Co-existence of acute myeloid leukemia with multilineage dysplasia and Epstein-Barr virus-associated T-cell lymphoproliferative disorder in a patient with rheumatoid arthritis: a case report

Rheumatoid arthritis (RA) is an autoimmune disease mediated by inflammatory processes mainly at the joints. Recently, awareness of Epstein-Barr virus (EBV)-associated T-cell lymphoproliferative disorder (T-LPD) has been heightened for its association with methotraxate usage in RA patients. In the contrary, acute myeloid leukemia with multilineage dysplasia (AML-MLD) has never been documented to be present concomitantly with the above two conditions. In this report we present a case of an autopsy-proven co-existence of AML-MLD and EBV-associated T-LPD in a patient with RA.

Stimulation of TLR2 and TLR4 differentially skews the balance of T cells in a mouse model of arthritis

TLRs may contribute to the progression of rheumatoid arthritis through recognition of microbial or host-derived ligands found in arthritic joints. Here, we show that TLR2 and TLR4, but not TLR9, are involved in the pathogenesis of autoimmune arthritis and play distinct roles in the regulation of T cells and cytokines. We investigated the involvement of TLR2, TLR4, and TLR9 in the progression of arthritis using IL-1 receptor antagonist-knockout (IL1rn-/-) mice, which spontaneously develop an autoimmune T cell-mediated arthritis. Spontaneous onset of arthritis was dependent on TLR activation by microbial flora, as germ-free mice did not develop arthritis. Clinical and histopathological evaluation of IL1rn-/-Tlr2-/- mice revealed more severe arthritis, characterized by reduced suppressive function of Tregs and substantially increased IFN-gamma production by T cells. IL1rn-/-Tlr4-/- mice were, in contrast, protected against severe arthritis and had markedly lower numbers of Th17 cells and a reduced capacity to produce IL-17. A lack of Tlr9 did not affect the progression of arthritis. While any therapeutic intervention targeting TLR2 still seems complicated, the strict position of TLR4 upstream of a number of pathogenic cytokines including IL-17 provides an interesting potential therapeutic target for rheumatoid arthritis.

Hyaluronan production in synoviocytes as a consequence of viral infections: HAS1 activation by Epstein-Barr virus and synthetic double- and single-stranded viral RNA analogs

One of the hallmarks of arthritis is swollen joints containing unusually high quantities of hyaluronan. Intact hyaluronan molecules facilitate cell migration by acting as ligands for CD44. Hyaluronan degradation products, readily formed at sites of inflammation, also fuel inflammatory processes. Irrespective of whether viruses could be a cause of rheumatoid arthritis, there is clear evidence that links viral infections to this debilitating disease. For this study, live Epstein-Barr virus and a number of double- and single-stranded synthetic viral analogs were tested for their effectiveness as activators of hyaluronan (HA) synthesis. As shown herein, Epstein-Barr virus-treated fibroblast-like synoviocytes significantly increase HA production and release. Real time reverse transcription-PCR data show that HAS1 mRNA levels are significantly elevated in virus-treated cells, whereas mRNA levels for the genes HAS2 and HAS3 remain unchanged. As to the mechanism of virus-induced HAS1 transcription, data are presented that imply that among the double- and single-stranded polynucleotides tested, homopolymeric polycytidylic structures are the most potent inducers of HAS1 transcription and HA release, whereas homopolymeric polyinosinic acid is without effect. Analyses of virus-induced signal cascades, utilizing chemical inhibitors of MAPK and overexpressing mutated IKK and IkappaB, revealed that the MAPK p38 as well as the transcription factor NF-kappaB are essential for virus-induced activation of HAS1. The presented data implicate HAS1 as the culprit in unfettered HA release and point out targets in virus-induced signaling pathways that might allow for specific interventions in cases of unwanted and uncontrolled HA synthesis.