Clinical correlations with Porphyromonas gingivalis antibody responses in patients with early rheumatoid arthritis

Periodontitis and periodontopathic bacteria as risk factors for rheumatoid arthritis: A review of the last 10 years

Rheumatoid arthritis (RA) is characterized by chronic inflammatory destruction of joint tissue and is caused by an abnormal autoimmune response triggered by interactions between genetics, environmental factors, and epigenetic and posttranslational modifications. RA has been suggested to be interrelated with periodontitis, a serious form or stage of chronic inflammatory periodontal disease associated with periodontopathic bacterial infections, genetic predisposition, environmental factors, and epigenetic influences. Over the last decade, a number of animal and clinical studies have been conducted to assess whether or not periodontitis and associated periodontopathic bacteria constitute risk factors for RA. The present review introduces recent accumulating evidence to support the associations of periodontitis and periodontopathic bacteria with the risk of RA or the outcome of RA pharmacological treatment with disease-modifying antirheumatic drugs. In addition, the results from intervention studies have suggested an improvement in RA clinical parameters after nonsurgical periodontal treatment. Furthermore, the potential causal mechanisms underlying the link between periodontitis and periodontopathic bacteria and RA are summarized.

The serum immunoglobulin G titres against Porphyromonas gingivalis as a predictor of clinical response to 1-year treatment with biological disease-modifying antirheumatic drugs in rheumatoid arthritis patients: A retrospective cohort study

OBJECTIVES

The aim is to evaluate the relevance of serum immunoglobulin G (IgG) titres against periodontopathic bacteria to predict the clinical response to 1-year treatment with biological disease-modifying antirheumatic drugs (bDMARDs) in rheumatoid arthritis (RA) patients.

METHODS

Data were collected from 50 RA patients who had received conventional synthetic DMARDs, corticosteroids, or non-steroidal anti-inflammatory drugs before (baseline) and after 1-year treatment with bDMARDs in a retrospective cohort study. Changes in rheumatologic conditions were compared between the two groups for low and high baseline IgG titres against Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans according to their median measurements.

RESULTS

Twenty-five patients with low anti-P. gingivalis IgG titres showed significantly greater decreases in changes in the Clinical Disease Activity Index and swollen joint count than 25 patients with high anti-P. gingivalis IgG titres (p = .04 for both). Bivariate and multivariate analyses revealed a significantly positive association of baseline anti-P. gingivalis IgG titres with Clinical Disease Activity Index changes (p = .02 and p = .002). However, post-treatment rheumatologic conditions were comparable between 25 patients each in the low and high baseline anti-A. actinomycetemcomitans IgG titre groups.

CONCLUSIONS

Baseline serum anti-P. gingivalis IgG titres are predictive of the clinical response to 1-year treatment with bDMARDs in RA patients.

Increased risk of periodontitis in patients with rheumatoid arthritis: A nationwide register study in Norway

AIM

To investigate the risk of periodontitis in rheumatoid arthritis (RA) patients in a nationwide register-based study.

MATERIALS AND METHODS

Patients and controls were defined using ICD-10 codes registered in the Norwegian Patient Registry (NPR), from 2011 to 2017. The 324,232 included subjects had at least one registered diagnostic code for RA (33,040 patients) or diagnostic codes for non-osteoporotic fractures or hip or knee replacement due to osteoarthritis (controls). The outcome was periodontitis, defined by codes for periodontal treatment from the Norwegian Control and Payment of Health Reimbursements Database (KUHR). Hazard ratios (HRs) were calculated for periodontitis in RA patients compared to controls. Generalized additive model in Cox regressions was estimated to visualize periodontitis occurrences as a function of number of RA visits.

RESULTS

The risk of periodontitis increased with increasing number of RA visits. RA patients having 10 or more visits during the 7-year period had a 50% increased risk of periodontitis compared to controls (HR = 1.48, 95% confidence interval [CI]: 1.39-1.59); also, in patients with assumed new RA, an even higher risk estimate was seen (HR = 1.82, 95% CI: 1.53-2.17).

CONCLUSIONS

In this register-based study in which periodontal treatment was used as a surrogate marker for periodontitis, we found an increased risk of periodontitis in RA patients, particularly those with active disease and new RA.

Tailored therapeutic decision of rheumatoid arthritis using proteomic strategies: how to start and when to stop?

Unpredictable treatment responses have been an obstacle for the successful management of rheumatoid arthritis. Although numerous serum proteins have been proposed, there is a lack of integrative survey to compare their relevance in predicting treatment outcomes in rheumatoid arthritis. Also, little is known about their applications in various treatment stages, such as dose modification, drug switching or withdrawal. Here we present an in-depth exploration of the potential usefulness of serum proteins in clinical decision-making and unveil the spectrum of immunopathology underlying responders to different drugs. Patients with robust autoimmunity and inflammation are more responsive to biological treatments and prone to relapse during treatment de-escalation. Moreover, the concentration changes of serum proteins at the beginning of the treatments possibly assist early recognition of treatment responders. With a better understanding of the relationship between the serum proteome and treatment responses, personalized medicine in rheumatoid arthritis will be more achievable in the near future.

Antibodies against Porphyromonas gingivalis in serum and saliva and their association with rheumatoid arthritis and periodontitis. Data from two rheumatoid arthritis cohorts in Sweden

Background

Periodontitis and oral pathogenic bacteria can contribute to the development of rheumatoid arthritis (RA). A connection between serum antibodies to Porphyromonas gingivalis (P. gingivalis) and RA has been established, but data on saliva antibodies to P. gingivalis in RA are lacking. We evaluated antibodies to P. gingivalis in serum and saliva in two Swedish RA studies as well as their association with RA, periodontitis, antibodies to citrullinated proteins (ACPA), and RA disease activity.

Methods

The SARA (secretory antibodies in RA) study includes 196 patients with RA and 101 healthy controls. The Karlskrona RA study includes 132 patients with RA ≥ 61 years of age, who underwent dental examination. Serum Immunoglobulin G (IgG) and Immunoglobulin A (IgA) antibodies and saliva IgA antibodies to the P. gingivalis-specific Arg-specific gingipain B (RgpB) were measured in patients with RA and controls.

Results

The level of saliva IgA anti-RgpB antibodies was significantly higher among patients with RA than among healthy controls in multivariate analysis adjusted for age, gender, smoking, and IgG ACPA (p = 0.022). Saliva IgA anti-RgpB antibodies were associated with RA disease activity in multivariate analysis (p = 0.036). Anti-RgpB antibodies were not associated with periodontitis or serum IgG ACPA.

Conclusion

Patients with RA had higher levels of saliva IgA anti-RgpB antibodies than healthy controls. Saliva IgA anti-RgpB antibodies may be associated with RA disease activity but were not associated with periodontitis or serum IgG ACPA. Our results indicate a local production of IgA anti-RgpB in the salivary glands that is not accompanied by systemic antibody production.

Gut Microbiota and Cardiovascular Disease: Evidence on the Metabolic and Inflammatory Background of a Complex Relationship

Several studies in recent years have demonstrated that gut microbiota-host interactions play an important role in human health and disease, including inflammatory and cardiovascular diseases. Dysbiosis has been linked to not only well-known inflammatory diseases, such as inflammatory bowel diseases, rheumatoid arthritis, and systemic lupus erythematous, but also to cardiovascular risk factors, such as atherosclerosis, hypertension, heart failure, chronic kidney disease, obesity, and type 2 diabetes mellitus. The ways the microbiota is involved in modulating cardiovascular risk are multiple and not only related to inflammatory mechanisms. Indeed, human and the gut microbiome cooperate as a metabolically active superorganism, and this affects host physiology through metabolic pathways. In turn, congestion of the splanchnic circulation associated with heart failure, edema of the intestinal wall, and altered function and permeability of the intestinal barrier result in the translocation of bacteria and their products into the systemic circulation, further enhancing the pro-inflammatory conditions underlying cardiovascular disorders. The aim of the present review is to describe the complex interplay between gut microbiota, its metabolites, and the development and evolution of cardiovascular diseases. We also discuss the possible interventions intended to modulate the gut microbiota to reduce cardiovascular risk.

The Role of the Oral Microbiome in the Development of Diseases

Periodontal disease (PD) is a complex and infectious illness that begins with a disruption of bacterial homeostasis. This disease induces a host inflammatory response, leading to damage of the soft and connective tooth-supporting tissues. Moreover, in advanced cases, it can contribute to tooth loss. The aetiological factors of PDs have been widely researched, but the pathogenesis of PD has still not been totally clarified. There are a number of factors that have an effect on the aetiology and pathogenesis of PD. It is purported that microbiological, genetic susceptibility and lifestyle can determine the development and severity of the disease. The human body’s defence response to the accumulation of plaque and its enzymes is known to be a major factor for PD. The oral cavity is colonised by a characteristic and complex microbiota that grows as diverse biofilms on all mucosal and dental surfaces. The aim of this review was to provide the latest updates in the literature regarding still-existing problems with PD and to highlight the role of the oral microbiome in periodontal health and disease. Better awareness and knowledge of the causes of dysbiosis, environmental risk factors and periodontal therapy can reduce the growing worldwide prevalence of PDs. The promotion of good oral hygiene, limiting smoking, alcohol consumption and exposure to stress and comprehensive treatment to decrease the pathogenicity of oral biofilm can help reduce PD as well as other diseases. Evidence linking disorders of the oral microbiome to various systemic diseases has increased the understanding of the importance of the oral microbiome in regulating many processes in the human body and, thus, its impact on the development of many diseases.

Treatment resistance of rheumatoid arthritis relates to infection of periodontal pathogenic bacteria: a case-control cross-sectional study

Recent studies have shown that periodontitis is associated with rheumatoid arthritis (RA) and periodontal bacteria, such as Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) are involved in the pathogenesis of RA via citrullinated proteins. Smoking has also been shown to be involved in the pathogenesis of RA; however, the extent of this involvement is still poorly understood. In addition, RA and polymyalgia rheumatica (PMR) are sometimes difficult to differentiate; however, the relationship between PMR and the factors from smoking and periodontal bacteria is unclear. The aim of this study was to clarify the relationship between periodontal pathogenic bacterial infections and smoking in patients with RA or PMR. This case–control study included 142 patients with untreated RA or PMR. This study evaluated the serum antibody titers against periodontal pathogenic bacterial antigens and an anti-citrullinated peptide antibody (ACPA). In patients with RA, the relationship between antibody titers and disease activity of RA and response after 3 months of treatment was also investigated. Additionally, the effects of smoking were evaluated. Although there was no significant difference in serum antibody titer against periodontal pathogenic bacteria between the ACPA-positive RA group and the ACPA-negative PMR group, we found an association between the elevated antibody titer against Pg and the degree of ACPA value, especially between negative group and high-value positive group (≥ 100 U/mL). The antibody titers against Aa and Pg did not differ depending on disease activity score 28 (DAS28) at baseline; however, patients with high antibody titers had poor RA therapeutic response as judged by DAS28 after 3 months. We could not find any association between smoking and any of these parameters. Periodontal pathogenic bacteria, especially Pg, are associated with elevated ACPA levels. Our findings suggest that Pg and Aa infections interfere with the therapeutic response of RA.

The Relationship Between Porphyromonas Gingivalis and Rheumatoid Arthritis: A Meta-Analysis

Rheumatoid arthritis (RA) is a systematical autoimmune disease, characterized by chronic synovial joint inflammation and hurt. Porphyromonas gingivalis(P. gingivalis) can cause life-threatening inflammatory immune responses in humans when the host pathogenic clearance machinery is disordered. Some epidemiological studies have reported that P. gingivalis exposure would increase the prevalence of RA. However, the results remain inconsistent. Therefore, a meta-analysis was done to systematically analyze the relationship between P. gingivalis exposure and the prevalence of rheumatoid arthritis. Database including Cochrane Library, Web of Science, PubMed, and EMBASE were searched for published epidemiological articles assessed the relationship between P. gingivalis and RA. Obtained studies were screened based on the predefined inclusion and exclusion criteria. The overall Odds Ratios (ORs) of incorporated articles were pooled by random-effect model with STATA 15.1 software. The literature search returned a total of 2057 studies. After exclusion, 28 articles were included and analyzed. The pooled ORs showed a significant increase in the risk of RA in individuals with P. gingivalis exposure (OR = 1.86; 95% CI: 1.43-2.43). Subgroup analysis revealed that pooled ORs from populations located in Europe (OR = 2.17; 95% CI: 1.46-3.22) and North America (OR = 2.50; 95% CI: 1.23-5.08) were significantly higher than that from population in Asia (OR = 1.11; 95% CI: 1.03-1.20). Substantial heterogeneity was observed but did not significantly influence the overall outcome. In conclusion, our results indicated P. gingivalis exposure was a risk factor in RA. Prompt diagnosis and management decisions on P. gingivalis antimicrobial therapy would prevent rheumatoid arthritis development and progression.

Pros and cons of causative association between periodontitis and rheumatoid arthritis

Research in recent decades has brought significant advancements in understanding of the molecular basis of the etiology of autoimmune diseases, including rheumatoid arthritis, a common systemic disease in which an inappropriate or inadequate immune response to environmental challenges leads to joint destruction. Recent studies have indicated that the classical viewpoint of the immunological processes underpinning the pathobiology of rheumatoid arthritis is restricted and needs to be expanded to include a more holistic and interdisciplinary approach incorporating bacteria-induced inflammatory reactions as an important pathway in rheumatoid arthritis etiology. Here, we discuss in detail data showing the clinical and molecular association of rheumatoid arthritis development with periodontal diseases. We also describe the unique role of periopathogens, which have been proposed to be crucial in the initiation and progression of this autoimmune pathological disorder.

Relation between anti-Porphyromonas gingivalis antibody titers and HLA-DRB1 neutral alleles in individuals with rheumatoid arthritis

OBJECTIVE

This study aimed to determine the relation between titres of anti-Porphyromonas gingivalis (P. gingivalis) antibody and rheumatoid arthritis (RA) HLA-DRB1 susceptibility region associated with shared epitope (SE) using the Gregersen's and de Vries's classification methods.

MATERIAL AND METHODS

In this cross-sectional study, results of immunoglobulin G1 (IgG1) and immunoglobulin G2 (IgG2) anti-P. gingivalis antibodies, anti-citrullinated protein antibodies (ACPA), diagnosis for RA, and periodontal disease (PD), and a genetic study of the HLA DRB1 region were obtained from 50 patients with RA and 50 control individuals.

RESULTS

Anti-P. gingivalis antibody levels and PD parameters were similar in control and RA groups. Anti-P. gingivalis antibodies were not associated with SE or ACPA. There was no association between ACPA and SE. However, de Vries' classification in RA patients revealed an association between the HLA DRB1 neutral alleles and higher titres of anti-P. gingivalis antibodies as follows: IgG1 anti-P. gingivalis ≥ 1:400 (p = .039); IgG2 anti-P. gingivalis ≥ 1:400 with neutral/neutral genotype (N/N), being exclusive for RA (p = .008); and IgG2 anti-P. gingivalis ≥ 1:200 and N/N (p = .016).

CONCLUSIONS

Although no association was found between SE and anti-P. gingivalis antibodies; according to the de Vries' classification, there was an existing association between HLA DRB1 neutral alleles, with high titres of IgG anti-P.gingivalis antibodies for RA, focussing on novel associations between P.gingivalis and RA.

Periodontitis and rheumatoid arthritis: What have we learned about their connection and their treatment?

Rheumatoid arthritis and periodontitis are chronic inflammatory diseases defined respectively by the destruction of the articular cartilage and tooth-supporting periodontal tissues. Although the epidemiologic evidence for an association between these two diseases is still scarce, there is emerging scientific information linking specific bacterial periodontal pathogens, such as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, in the citrullination process, leading to autoantibody formation and compromised immunotolerance of the susceptible patient to rheumatoid arthritis. In this review, we update the existing information on the evidence, not only regarding the epidemiologic association, but also the biologic mechanisms linking these two diseases. Finally, we review information emerging from intervention studies evaluating whether periodontal treatment could influence the initiation and progression of rheumatoid arthritis.

Multifaceted Impacts of Periodontal Pathogens in Disorders of the Intestinal Barrier

Periodontal disease, a common inflammatory disease, is considered a hazardous factor that contributes to the development of diseases of the digestive system as well as other systems. The bridge between periodontitis and systemic diseases is believed to be periodontal pathogens. The intestine, as part of the lower gastrointestinal tract, has a close connection with the oral cavity. Within the intestine, the intestinal barrier acts as a multifunctional system including microbial, mucous, physical and immune barrier. The intestinal barrier forms the body's first line of defense against external pathogens; its breakdown can lead to pathological changes in the gut and other organs or systems. Reports in the literature have described how oral periodontal pathogens and pathobiont-reactive immune cells can transmigrate to the intestinal mucosa, causing the destruction of intestinal barrier homeostasis. Such findings might lead to novel ideas for investigating the relationship between periodontal disease and other systemic diseases. This review summarizes studies on the effects of periodontal pathogens on the intestinal barrier, which might contribute to understanding the link between periodontitis and gastrointestinal diseases.

Progress in Oral Microbiome Related to Oral and Systemic Diseases: An Update

The human oral microbiome refers to an ecological community of symbiotic and pathogenic microorganisms found in the oral cavity. The oral cavity is an environment that provides various biological niches, such as the teeth, tongue, and oral mucosa. The oral cavity is the gateway between the external environment and the human body, maintaining oral homeostasis, protecting the mouth, and preventing disease. On the flip side, the oral microbiome also plays an important role in the triggering, development, and progression of oral and systemic diseases. In recent years, disease diagnosis through the analysis of the human oral microbiome has been realized with the recent development of innovative detection technology and is overwhelmingly promising compared to the previous era. It has been found that patients with oral and systemic diseases have variations in their oral microbiome compared to normal subjects. This narrative review provides insight into the pathophysiological role that the oral microbiome plays in influencing oral and systemic diseases and furthers the knowledge related to the oral microbiome produced over the past 30 years. A wide range of updates were provided with the latest knowledge of the oral microbiome to help researchers and clinicians in both academic and clinical aspects. The microbial community information can be utilized in non-invasive diagnosis and can help to develop a new paradigm in precision medicine, which will benefit human health in the era of post-metagenomics.

Porphyromonas gingivalis: where do we stand in our battle against this oral pathogen?

Periodontal diseases, such as gingivitis and periodontitis, are inflammatory diseases triggered by pathogenic bacteria that lead to damage of the soft tissue and bone supporting the teeth. Amongst the identified oral periodontopathogenic bacteria, Porphyromonas gingivalis is able to enhance oral dysbiosis, which is an imbalance in the beneficial commensal and periodontal pathogenic bacteria that induces chronic inflammation. Given the critical role of oral pathogenic bacteria like P. gingivalis in the pathogenesis of periodontitis, local and/or systemic antibacterial therapy has been suggested to treat this disease, especially in its severe or refractory forms. Nevertheless, the majority of the antibacterial agents currently used for the treatment of periodontal diseases are broad-spectrum, which harms beneficial bacterial species that are critical in health, inhibit the growth of pathogenic bacteria, contribute in protecting the periodontal tissues to damage and aid in its healing. Thus, the development of more effective and specific antibacterial agents is needed to control oral pathogens in a polymicrobial environment. The strategies for the development of novel antibacterial agents include natural product isolation as well as synthetic and semi-synthetic methodologies. This review presents an overview of the periodontal diseases gingivitis and periodontitis along with current antibacterial treatment options (i.e., classes of antibacterial agents and the mechanism(s) of resistance that hinder their usage) used in periodontal diseases that specifically target oral pathogens such as P. gingivalis. In addition, to help medicinal chemists gain a better understanding of potentially promising scaffolds, this review provides an in-depth coverage of the various families of small molecules that have been investigated as potential anti-P. gingivalis agents, including novel families of compounds, repositioned drugs, as well as natural products.

Probiotics and Amelioration of Rheumatoid Arthritis: Significant Roles of Lactobacillus casei and Lactobacillus acidophilus

Rheumatoid arthritis is a chronic autoimmune disorder that can lead to disability conditions with swollen joints, pain, stiffness, cartilage degradation, and osteoporosis. Genetic, epigenetic, sex-specific factors, smoking, air pollution, food, oral hygiene, periodontitis, Prevotella, and imbalance in the gastrointestinal microbiota are possible sources of the initiation or progression of rheumatoid arthritis, although the detailed mechanisms still need to be elucidated. Probiotics containing Lactobacillus spp. are commonly used as alleviating agents or food supplements to manage diarrhea, dysentery, develop immunity, and maintain general health. The mechanism of action of Lactobacillus spp. against rheumatoid arthritis is still not clearly known to date. In this narrative review, we recapitulate the findings of recent studies to understand the overall pathogenesis of rheumatoid arthritis and the roles of probiotics, particularly L. casei or L. acidophilus, in the management of rheumatoid arthritis in clinical and preclinical studies.

The pre-clinical phase of rheumatoid arthritis: From risk factors to prevention of arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease considered as a multistep process spanning from the interaction of genetic (e.g., shared epitope or non-HLA loci), environmental and behavioral risk factors (e.g., smoking) leading to breaking immune tolerance and autoimmune processes such as the production of autoantibodies (e.g., antibodies against citrullinated proteins ACPA or rheumatoid factors, RF), development of the first symptoms without clinical arthritis, and, finally, the manifestation of arthritis. Despite the typical joint involvement in established RA, the pathogenesis of the disease likely begins far from joint structures: in the lungs or periodontium in association with citrullination, intestinal microbiome, or adipose tissue, which supports normal findings in synovial tissue in ACPA+ patients with arthralgia. The presence of ACPA is detectable even years before the first manifestation of RA. The pre-clinical phase of RA is the period preceding clinically apparent RA with ACPA contributing to the symptoms without subclinical inflammation. While the combination of ACPA and RF increases the risk of progression to RA by up to 10 times, increasing numbers of novel autoantibodies are to be investigated to contribute to the increased risk and pathogenesis of RA. With growing knowledge about the course of RA, new aspiration emerges to cure and even prevent RA, shifting the "window of opportunity" to the pre-clinical phases of RA. The clinical definition of individuals at risk of developing RA (clinically suspect arthralgia, CSA) makes it possible to unify these at-risk individuals' clinical characteristics for "preventive" treatment in ongoing clinical trials using mostly biological or conventional synthetic disease-modifying drugs. However, the combination of symptoms, laboratory, and imaging biomarkers may be the best approach to select the correct target at-risk population. The current review aims to explore different phases of RA and discuss the potential of (non)pharmacological intervention aiming to prevent RA.

Periodontal inflammation and distinct inflammatory profiles in saliva and gingival crevicular fluid (GCF) compared with serum and joints in rheumatoid arthritis patients

BACKGROUND

The association of periodontitis and Porphyromonas gingivalis (Pg) with rheumatoid arthritis (RA) is incompletely understood. To gain further insights, we evaluated periodontal status, oral, serum and joint inflammatory profiles, and Pg biomarkers in RA patients.

METHODS

In this cross-sectional study, we evaluated 33 patients with predominantly untreated new-onset RA, 20 healthy individuals (HIs), and 20 non-RA chronic periodontitis patients. Thirteen mediators (IFN-γ, IL-10, IL-17A, IL-6, IL-8, CXCL10, TNF-α, CXCL13, IL-23, MMP-1, MMP-3, MMP-8, MMP-9) were measured in serum, synovial fluid, saliva and gingival crevicular fluid (GCF) by multiplex immunoassay. Serum Pg IgG antibodies and subgingival Pg DNA were determined.

RESULTS

Most RA patients (91%) received routine dental care; only one currently smoked. Ten (30.3%) had periodontal health, 13 (39.4%) had gingivitis, and 10 (30.3%) had periodontitis. Th1 and innate immune responses predominated in serum. Many mediators were concentrated in joints, particularly IL-6, IL-8, and CXCL10. However, salivary and GCF profiles were more restricted, emphasizing neutrophilic inflammation (IL-8, MMP-8) and MMP-9. Compared with HI, most RA patients, regardless of periodontal status, had significantly elevated oral fluid levels of these mediators, with suppression of GCF IL-10, a pattern similar to non-RA periodontitis patients. Pg antibodies or DNA however were primarily associated with clinical periodontitis.

CONCLUSIONS

Despite routine dental care, RA patients often had inflammation in oral fluids, but inflammatory profiles differed from serum and joints. Neutrophilic inflammatory profiles in oral fluids, regardless of periodontal status, suggests that gingival tissues are a common, and often unrecognized, site of extra-articular inflammation in RA.

Associations between serum antibodies to periodontal pathogens and preclinical phases of rheumatoid arthritis

OBJECTIVES

To examine whether serum antibodies against selected periodontal pathogens are associated with early symptoms of RA development in healthy individuals at risk of developing the disease.

METHODS

Within an ongoing study cohort of first-degree relatives of patients with RA (RA-FDRs), we selected four groups corresponding to specific preclinical phases of RA development (n = 201). (i) RA-FDR controls without signs and symptoms of arthritis nor RA-related autoimmunity (n = 51); (ii) RA-FDRs with RA-related autoimmunity (n = 51); (iii) RA-FDRs with inflammatory arthralgias without clinical arthritis (n = 51); and (iv) RA-FDRs who have presented at least one swollen joint ('unclassified arthritis') (n = 48). Groups were matched for smoking, age, sex and shared epitope status. The primary outcome was IgG serum levels against five selected periodontal pathogens and one commensal oral species assessed using validated-in-house ELISA assays. Associations between IgG measurements and preclinical phases of RA development were examined using Kruskal-Wallis or Mann-Whitney tests (α = 0.05).

RESULTS

None of the IgGs directed against individual periodontal pathogens significantly differed between the four groups of RA-FDRs. Further analyses of cumulated IgG levels into bacterial clusters representative of periodontal infections revealed significantly higher IgG titres against periodontopathogens in anti-citrullinated protein antibodies (ACPA)-positive RA-FDRs (P = 0.015). Current smoking displayed a marked trend towards reduced IgG titres against periodontopathogens.

CONCLUSION

Our results do not suggest an association between serum IgG titres against individual periodontal pathogens and specific preclinical phases of RA development. However, associations between cumulative IgG titres against periodontopathogens and the presence of ACPAs suggest a synergistic contribution of periodontopathogens to ACPA development.

Microbial Lipid A Remodeling Controls Cross-Presentation Efficiency and CD8 T Cell Priming by Modulating Dendritic Cell Function

The majority of Gram-negative bacteria elicit a potent immune response via recognition of lipid A expressed on the outer bacterial membrane by the host immune receptor Toll-like receptor 4 (TLR4). However, some Gram-negative bacteria evade detection by TLR4 or alter the outcome of TLR4 signaling by modification of lipid A species. Although the role of lipid A modifications on host innate immunity has been examined in some detail, it is currently unclear how lipid A remodeling influences host adaptive immunity. One prototypic Gram-negative bacterium that modifies its lipid A structure is Porphyromonas gingivalis, an anaerobic pathobiont that colonizes the human periodontium and induces chronic low-grade inflammation that is associated with periodontal disease as well as a number of systemic inflammatory disorders. P. gingivalis produces dephosphorylated and deacylated lipid A structures displaying altered activities at TLR4. Here, we explored the functional role of P. gingivalis lipid A modifications on TLR4-dependent innate and adaptive immune responses in mouse bone marrow-derived dendritic cells (BMDCs). We discovered that lipid A 4'-phosphate removal is required for P. gingivalis to evade BMDC-dependent proinflammatory cytokine responses and markedly limits the bacterium's capacity to induce beta interferon (IFN-β) production. In addition, lipid A 4'-phosphatase activity prevents canonical bacterium-induced delay in antigen degradation, which leads to inefficient antigen cross-presentation and a failure to cross-prime CD8 T cells specific for a P. gingivalis-associated antigen. We propose that lipid A modifications produced by this bacterium alter host TLR4-dependent adaptive immunity to establish chronic infections associated with a number of systemic inflammatory disorders.

Streptococcus species enriched in the oral cavity of patients with RA are a source of peptidoglycan-polysaccharide polymers that can induce arthritis in mice

OBJECTIVES

Analysis of oral dysbiosis in individuals sharing genetic and environmental risk factors with rheumatoid arthritis (RA) patients may illuminate how microbiota contribute to disease susceptibility. We studied the oral microbiota in a prospective cohort of patients with RA, first-degree relatives (FDR) and healthy controls (HC), then genomically and functionally characterised streptococcal species from each group to understand their potential contribution to RA development.

METHODS

After DNA extraction from tongue swabs, targeted 16S rRNA gene sequencing and statistical analysis, we defined a microbial dysbiosis score based on an operational taxonomic unit signature of disease. After selective culture from swabs, we identified streptococci by sequencing. We examined the ability of streptococcal cell walls (SCW) from isolates to induce cytokines from splenocytes and arthritis in ZAP-70-mutant SKG mice.

RESULTS

RA and FDR were more likely to have periodontitis symptoms. An oral microbial dysbiosis score discriminated RA and HC subjects and predicted similarity of FDR to RA. Streptococcaceae were major contributors to the score. We identified 10 out of 15 streptococcal isolates as S. parasalivarius sp. nov., a distinct sister species to S. salivarius. Tumour necrosis factor and interleukin 6 production in vitro differed in response to individual S. parasalivarius isolates, suggesting strain specific effects on innate immunity. Cytokine secretion was associated with the presence of proteins potentially involved in S. parasalivarius SCW synthesis. Systemic administration of SCW from RA and HC-associated S. parasalivarius strains induced similar chronic arthritis.

CONCLUSIONS

Dysbiosis-associated periodontal inflammation and barrier dysfunction may permit arthritogenic insoluble pro-inflammatory pathogen-associated molecules, like SCW, to reach synovial tissue.

Microbial Influences of Mucosal Immunity in Rheumatoid Arthritis

PURPOSE OF REVIEW

This review will summarize recent data defining the relationship between rheumatoid arthritis (RA) and the microbiome at mucosal sites throughout the body. It will highlight what is known, what is speculated, and current knowledge gaps regarding the microbiome in RA.

RECENT FINDINGS

An extensive relationship between the microbiome and immune cell function can influence RA-related inflammation and T cell and B cell biology. Studies are beginning to characterize microbial changes in individuals who are at risk for RA, which is a critical element needed to understand the influence of the microbiome on RA pathogenesis. Expanding our understanding of the microbiome in RA beyond the bacteria at the gut and oral mucosae into the lung and urogenital surfaces, including viral and fungal components, and establishing the relationship across mucosal sites will be critical in future work. Importantly, approaches to manipulate the microbiome could lead to novel therapeutic and preventive strategies.

Porphyromonas gingivalis and rheumatoid arthritis

PURPOSE OF REVIEW

To explore the pathogenic association between periodontal disease and rheumatoid arthritis focusing on the role of Porphyromonas gingivalis.

RECENT FINDINGS

In the last decades our knowledge about the pathogenesis of rheumatoid arthritis substantially changed. Several evidences demonstrated that the initial production of autoantibodies is not localized in the joint, rather in other immunological-active sites. A central role seems to be played by periodontal disease, in particular because of the ability of P. gingivalis to induce citrullination, the posttranslational modification leading to the production of anticitrullinated protein/peptide antibodies, the most sensitive and specific rheumatoid arthritis biomarker.

SUMMARY

The pathogenic role of P. gingivalis has been demonstrated in mouse models in which arthritis was either triggered or worsened in infected animals. P. gingivalis showed its detrimental role not only by inducing citrullination but also by means of other key mechanisms including induction of NETosis, osteoclastogenesis, and Th17 proinflammatory response leading to bone damage and systemic inflammation.

The microbiome and rheumatoid arthritis

Rheumatoid Arthritis (RA) is a severe, chronic autoimmune disease that affects 1% of the world's population. Familial risk contributes 50% of the risk of seropositive RA, with strongest risks seen in first-degree relatives. Smoking increases the risk of developing anti-citrullinated peptide antibody (ACPA)⁺ RA, particularly in individuals with high-risk RA-susceptibility alleles. Other contributory environmental risks including particulate exposure, periodontal disease, bronchiectasis, diet, obesity and the oral contraceptive impact respiratory, oral, intestinal and genital tract mucosal sites. Furthermore, the first signs of autoimmunity may appear at mucosal sites e.g. sputum ACPA-IgA and IgG. While oral and faecal dysbiosis are well described, there is no consistent single bacterial species that appears to drive RA. Animal and human data suggest a model in which multiple environmental influences impact mucosal immune function through the host genetics through enhanced mucosal permeability and the traffic of pro-inflammatory PAMPs and the amplification of autoimmune responses. In some cases, autoimmunity may be driven by cross-reactivity, or mimicry, to pathogen-specific antigens, particularly where the host immune system fails to support their rapid control and elimination.

Host-microbiota interactions in rheumatoid arthritis

The gut microbiota has been proposed to be an important environmental factor in the development of rheumatoid arthritis (RA). Here, we review a growing body of evidence from human and animal studies that supports the hypothesis that intestinal microbiota play a role in RA. Previous studies from we and others showed an altered composition of the microbiota in early RA patients. A recent study demonstrated that Prevotella species are dominant in the intestine of patients in the preclinical stages of RA. In addition, Prevotella-dominated microbiota isolated from RA patients contributes to the development of Th17 cell-dependent arthritis in SKG mice. Moreover, it was reported that periodontal bacteria correlates with the pathogenesis of RA. In this review, we discuss the link between oral bacteria and the development of arthritis. However, many questions remain to be elucidated in terms of molecular mechanisms for the involvement of intestinal and oral microbiota in RA pathogenesis.

Microbes living in the gut and mouth have been implicated in the development of rheumatoid arthritis (RA) and treatments that promote the growth of healthier bacterial communities may help weaken this autoimmune disease. Yuichi Maeda and Kiyoshi Takeda from Osaka University, Japan, review data from mice and humans linking RA to altered microbial compositions in the gut. They focus on a particular bacterium called Prevotella copri, which is found at much higher numbers in the gastrointestinal tracts of people with newly diagnosed RA than in those without the disease. Certain mouth-dwelling bacteria may also help exacerbate RA through the induction of antibodies directed against the host. The exact molecular mechanism by which gut and oral microbes contribute to RA remains unclear.

Association between anti-Porphyromonas gingivalis antibody, anti-citrullinated protein antibodies, and rheumatoid arthritis : A meta-analysis

OBJECTIVE

The aim of this study was to determine the relationship between anti-Porphyromonas gingivalis (anti-P. gingivalis) antibody levels and rheumatoid arthritis (RA) and its correlation with anti-citrullinated protein antibodies (ACPA).

METHODS

We performed a meta-analysis of studies comparing (a) anti-P. gingivalis antibody levels in RA patients and healthy controls and (b) the correlation coefficients between the anti-P. gingivalis antibody levels and ACPA in RA patients.

RESULTS

The study included 14 articles with 3829 RA patients and 1239 controls. Our meta-analysis showed that anti-P. gingivalis antibody levels were significantly higher in the RA group than in the control group (standardized mean difference [SMD] = 0.630, 95% CI = 0.272-0.989, p = 0.001). Subgroup analysis revealed that RA patients had significantly elevated anti-P. gingivalis antibody levels compared with healthy controls, but not compared with the non-RA control group and also not between different sample sizes. Anti-P. gingivalis antibody levels were significantly higher in the RA group than in the control group in the age-/sex-matched population, but not in the unmatched population. Anti-P. gingivalis antibody levels were significantly higher in the ACPA-positive group than in the ACPA-negative group (SMD = 0.322, 95% CI = 0.164-0.480, p = 6.4 × 10^-5). Meta-analysis of the correlation coefficients showed a significant positive correlation between anti-P. gingivalis antibody levels and ACPA (correlation coefficient = 0.147, 95% CI = 0.033-0.258, p = 0.012).

CONCLUSION

Our meta-analysis demonstrated that anti-P. gingivalis antibody levels were significantly higher in patients with RA and they were positively correlated with ACPA.

Role of good oral hygiene on clinical evolution of rheumatoid arthritis: a randomized study nested in the ESPOIR cohort

Objective

There is a relationship between RA and periodontal disease. We aimed to investigate if a good oral hygiene could improve activity of RA.

Methods

The patients with RA according to ACR/EULAR 2010 criteria and included in the French early arthritis ESPOIR cohort were included in a randomized nested study into: (i) intervention group: general recommendations of good oral hygiene including teeth brushing, daily antiseptic mouthwash and twice a year scaling; and (ii) control group: no intervention. The primary end point was the delta DAS28-ESR.

Results

Four hundred and seventy-two patients were randomized (238 in intervention and 234 in control). 92/238 from the intervention group accepted the procedure and 81 had a first visit to the dentist. 56% of patients had periodontal disease at baseline. Duration of RA was 9.0±0.7 years. Baseline DAS28-ESR was 2.7±1.3. After a median duration of 24 months, delta DAS28-ESR was −0.17±1.29 and −0.09±1.28 in intervention and control groups, respectively (mean difference (complier average causal effect): −0.37 (95% CI −1.12, 0.37), P = 0.33). In the intervention group, there was a significant decrease of the bacteria involved in the red complex: Porphyromonas gingivalis (P = 0.002), Tannerella forsythia (P = 0.002) and Treponema denticola (P = 0.019). The patients with baseline periodontal disease and those who became negative for one red complex bacterium had a slightly more important decrease of DAS28-ESR.

Conclusion

Oral hygiene instruction together with regular scaling and polishing of the teeth significantly decreased the load of periodontal pathogens but did not decrease RA activity. This intervention should be tested in patients with earlier RA and more active disease.

Trial registration

ClinicalTrials.gov, http://clinicaltrials.gov, NCT01831648.

Rheumatoid Arthritis-Associated Mechanisms of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology characterized by immune-mediated damage of synovial joints and antibodies to citrullinated antigens. Periodontal disease, a bacterial-induced inflammatory disease of the periodontium, is commonly observed in RA and has implicated periodontal pathogens as potential triggers of the disease. In particular, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans have gained interest as microbial candidates involved in RA pathogenesis by inducing the production of citrullinated antigens. Here, we will discuss the clinical and mechanistic evidence surrounding the role of these periodontal bacteria in RA pathogenesis, which highlights a key area for the treatment and preventive interventions in RA.

The Influence of Porphyromonas Gingivalis Bacterium Causing Periodontal Disease on the Pathogenesis of Rheumatoid Arthritis: Systematic Review of Literature

Periodontal pathologies are highly widespread throughout the world. Epidemiological studies have shown that as much as 1% of the population is suffering from periodontal disease. In recent years, there has been a growing number of studies linking these diseases with autoimmune diseases, especially with rheumatoid arthritis. This literature review evaluates changes in the relationship between periodontal pathologies caused by the bacterium Porphyromonas gingivalis and rheumatoid arthritis. The systematic review of the literature was performed according to the PRISMA analysis protocol. The review was performed with articles from the PubMed database. Searched articles were not older than 5 years. Only full texts and research performed with people were selected. A total of 56 results were received. A review and analysis of their full texts have been carried out and 10 articles were selected according to the established criteria. They were analyzed and results were presented. The results obtained from the literature were based on the influence of Porphyromonas gingivalis on the pathogenesis of rheumatoid arthritis. In the literature, the activity of this bacterium is explained by the analysis of its enzyme peptidylarginine deiminase and its principle of action. Studies have also been found to prove the presence of Porphyromonas gingivalis not only in the oral cavity but its DNA is also found in synovial fluid and plasma. In the researched articles, direct links between Porphyromonas gingivalis and rheumatoid arthritis have led doctors to draw attention to patients' oral hygiene and the condition of parodentium, as this may be the cause of autoimmune lesions. Treatment of periodontal disease will not only help maintain a healthy oral cavity but prevent the spread of bacteria to the surrounding tissues.

Infliximab Induced a Dissociated Response of Severe Periodontal Biomarkers in Rheumatoid Arthritis Patients

OBJECTIVE

Rheumatoid arthritis and periodontal disease are associated together, but the effect of therapy provided for one disease to the second one remained under-investigated. This study investigated effect of infliximab therapy used to treat rheumatoid arthritis (RA) on various biomarkers of periodontal disease (PD) severity including serologies of Porphyromonas gingivalis and Prevotella intermedia and matrix metalloproteinase 3.

METHODS

Seventy nine RA patients were enrolled at the time to start infliximab therapy and the 28 joint disease activity score (DAS28), anti-cyclic citrullinated petides 2nd generation (anti-CCP2), anti-P. gingivalis antibody, and Matrix metalloproteinase 3 (MMP-3) were monitored before and at 6 months of infliximab therapy. Joint damage and severe periodontal disease were assessed at baseline. Anti-CCP2, anti-P. gingivalis antibody, and MMP-3 were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

At baseline, anti-CCP2 titers were associated with anti-P. gingivalis lipopolysaccharide (LPS)-specific antibodies titers (p < 0.05). Anti-P. gingivalis antibodies were not significantly correlated with clinical, biological, or destruction parameters of RA disease. At 6 months of infliximab therapy, MMP-3 level decreased (from 119 ± 103 ng/mL to 62.44 ± 52 ng/mL; p < 0.0001), whereas P. gingivalis antibody levels remained at the same level. DAS28 and inflammation markers C-reactive protein (CRP) and Erythrocyte sedimentation rate (ESR) also decreased significantly during infliximab therapy (p < 0.05) as anti-CCP2 levels (p < 0.001). Only high MMP-3 level at baseline was associated with infliximab efficacy (p < 0.01).

CONCLUSION

MMP-3 level can be a useful marker of the efficacy of infliximab in RA patients. The treatment did not affect anti-P. gingivalis antibodies.

Robust interferon signature and suppressed tissue repair gene expression in synovial tissue from patients with postinfectious, Borrelia burgdorferi-induced Lyme arthritis

In most patients with Lyme arthritis (LA), antibiotic therapy results in Borrelia burgdorferi pathogen elimination, tissue repair, and return to homeostasis. However, despite spirochetal killing, some patients develop proliferative synovitis, characterised by synovial hyperplasia, inflammation, vascular damage, and fibrosis that persists for months to several years after antibiotic treatment, called postinfectious LA. In this study, we characterised the transcriptomes of postinfectious LA patients' synovial tissue, the target tissue of the immune response. High-throughput RNA sequencing to a depth of ~30 million reads per sample was used to profile gene expression in synovial tissue from 14 patients with postinfectious LA, compared with eight patients with other types of chronic inflammatory arthritis and five with minimally inflammatory osteoarthritis (OA). Synovium from postinfectious LA and other inflammatory arthritides shared gene signatures associated with antigen presentation, innate immune responses, and cell-mediated immune activation, whereas these responses were diminished in OA synovium. Unique to postinfectious LA was a particularly robust interferon-gamma (IFNγ) signature. Moreover, this heightened IFNγ signature inversely correlated with expression of genes involved in repair of damaged tissue, including genes associated with stromal cell proliferation and differentiation, neovascularisation, and extracellular matrix synthesis, which were markedly suppressed in postinfectious LA. Transcriptional observations were confirmed by cytokine profiling, histologic analyses, and clinical correlations. We propose that in patients with postinfectious LA, overexpression of IFNγ in synovium prevents appropriate repair of tissue damaged by B. burgdorferi infection, blocking return to tissue homeostasis long after completion of antibiotic therapy and resolution of active infection.

An orally administered oral pathobiont and commensal have comparable and innocuous systemic effects in germ-free mice

BACKGROUND AND OBJECTIVES

We recently proposed a novel mechanism linking periodontitis and systemic diseases, in which orally administered Porphyromonas gingivalis affects gut microbiota composition and subsequently leads to systemic inflammation. However, the mechanism by which P. gingivalis generates systemic effects from the gut is unknown.

MATERIAL AND METHODS

Six-week-old germ-free mice were orally administered with either an oral pathobiont P. gingivalis or an oral commensal Lactobacillus salivarius twice a week for 5 weeks. Control mice were administered with vehicle only. Alveolar bone resorption was evaluated histologically. The expression profile of various genes was analyzed in gingival tissue, liver, small intestine and large intestine using real-time polymerase chain reaction. Sera were analyzed for antibody, endotoxin and interleukin (IL)-6 levels. Antibody levels were also analyzed for culture supernatant of cells from mesenteric lymph nodes and spleens. A proportion of T-helper 17 and Treg in the cells from mesenteric lymph nodes and spleens was analyzed by flow cytometry. The level of IL-6 and IL-17 in the cell culture supernatants was analyzed by enzyme-linked immunosorbent assay.

RESULTS

P. gingivalis administration did not induce alveolar bone resorption. Although P. gingivalis elicited systemic antibody response in germ-free mice, unlike in specific pathogen-free mice, P. gingivalis did not induce an inflammatory response in gingiva, liver and intestinal tissue, or alter the proportion of T-helper 17 and Treg. However, IL-6 and IL-17 productions were significantly elevated and tended to be elevated, respectively, in the cells from mesenteric lymph nodes of P. gingivalis-administered mice. Interestingly, the expression of IL-10 and tight junction protein in the gingiva and intestine, respectively, was significantly upregulated in P. gingivalis-treated mice. Administration of L. salivarius elicited almost similar effects as P. gingivalis.

CONCLUSION

The oral pathobiont P. gingivalis did not induce any detectable pathogenic changes or any major host responses when administered to germ-free mice. There may be indirect mechanisms for gut-mediated systemic effects by P. gingivalis.

Papel de la Porphyromonas gingivalis en la patogenicidad de la Artritis Reumatoide: revisión de la literatura

Introducción: la evidencia cientí ca sobre la Artritis Reumatoide (AR) y la Enfermedad Periodontal (EP) se ha orientado hacia la presencia del periodontopatógeno Porphyromonas gingivalis (P.g). Se ha establecido, a partir de diferentes estudios, su relación con el proceso de citrulinación y producción de anticuerpos antipéptidos citrulinados. Actualmente, hay una heterogénea evidencia cientí ca con nuevos aportes y variabilidad de hallazgos entre las dos enfermedades, pero los estudios en humanos son los que más generan interés. Objetivo: revisar evidencia cientí ca sobre estudios clínicos relacionados con la patogenicidad de la Enfermedad Periodontal y Porphyromonas gingivalis en la Artritis Reumatoide. Metodología: por medio de una búsqueda se identi caron las publicaciones realizadas con los tópicos de nidos y te- niendo en cuenta el análisis de contenido de estudios clínicos. Se revisó en el período de 2012-2016, los términos de búsqueda empleados fueron: rheumatoid arthritis y Porphyromonas gingivalis, con una lectura inicial basada en títulos y resúmenes, se excluyeron revisiones, reporte de casos, estudios in vitro y en animales. Resultados: después de realizar la búsqueda en tres bases de datos (PubMed, Lilacs y Embase), se encontraron 166 artículos, de los cuales 140 fueron rechazados y 25 fueron incluidos, pues describían estudios clínicos entre AR y P.g. La mayoría mostró una investigación de tipo cuantitativo, determinando la presencia de P.g en los pacientes con AR. Es clara la presencia de anticuerpos de P.g en suero y se ha reportado poca presencia en líquido sinovial, se ha identi cado ADN bacteriano en pacientes con AR y enfermedad periodontal. Nueva evidencia sugiere asociaciones con otros patógenos y detección en artritis de aparición temprana. 

Aggravation of collagen-induced arthritis by orally administered Porphyromonas gingivalis through modulation of the gut microbiota and gut immune system

Porhyromonas gingivalis, a causative bacterium of periodontitis, is implicated in the etiology of rheumatoid arthritis (RA), mainly because of expressing peptidyl arginine deiminase (PAD) that generates RA-related autoantigens. However, compared with other periodontopathic bacteria, the precise role of P. gingivalis in RA is largely unknown. We found that orally administered P. gingivalis changed the gut microbiome with concomitant elevation of serum endotoxin and inflammatory markers, and impairment of the gut barrier function. Based on findings showing a relationship between gut microbiota and RA, we investigated whether the change of gut microbiota induced by P. gingivalis and Prevotella intermedia, another periodontopathic bacterium without PAD, is associated with collagen-induced arthritis (CIA). DBA/1J mice were orally administered with or without bacteria followed by induction of CIA. P. gingivalis, but not P. intermedia, administration significantly aggravated arthritis with increased interleukin-17 levels in sera and culture supernatants, increased Th17 cell proportions among mesenteric lymphocytes, and a significant change in the gut microbiome. However, P. gingivalis administration did not elevate the level of anti-citrullinated protein antibody. These results suggest a unique role of P. gingivalis in the link between periodontitis and RA by affecting the gut immune system and the gut microbiota composition.

Autoimmune Arthritides, Rheumatoid Arthritis, Psoriatic Arthritis, or Peripheral Spondyloarthritis Following Lyme Disease

OBJECTIVE

To describe systemic autoimmune joint diseases that develop following Lyme disease, and to compare their clinical features with those of Lyme arthritis (LA).

METHODS

We reviewed records of all adult patients referred to our LA clinic over a 13-year period, in whom we had diagnosed a systemic autoimmune joint disease following Lyme disease. For comparison, records of patients enrolled in our LA cohort over the most recent 2-year period were analyzed. Levels of IgG antibodies to Borrelia burgdorferi and to 3 Lyme disease-associated autoantigens were measured.

RESULTS

We identified 30 patients who had developed a new-onset systemic autoimmune joint disorder a median of 4 months after Lyme disease (usually manifested by erythema migrans [EM]). Fifteen had rheumatoid arthritis (RA), 13 had psoriatic arthritis (PsA), and 2 had peripheral spondyloarthritis (SpA). The 30 patients typically had polyarthritis, and those with PsA or SpA often had previous psoriasis, axial involvement, or enthesitis. In the comparison group of 43 patients with LA, the usual clinical picture was monoarticular knee arthritis, without prior EM. Most of the patients with systemic autoimmune joint disorders were positive for B burgdorferi IgG antibodies, as detected by enzyme-linked immunosorbent assay, but had significantly lower titers and lower frequencies of Lyme disease-associated autoantibodies than patients with LA. Prior to our evaluation, these patients had often received additional antibiotics for presumed LA, without benefit. We prescribed antiinflammatory agents, most commonly disease-modifying antirheumatic drugs, resulting in improvement.

CONCLUSION

Systemic autoimmune joint diseases (i.e., RA, PsA, SpA) may follow Lyme disease. Development of polyarthritis after antibiotic-treated EM, previous psoriasis, or low-titer B burgdorferi antibodies may provide insight into the correct diagnosis.

Association Between Serum Antibodies to Periodontal Bacteria and Rheumatoid Factor in the Third National Health and Nutrition Examination Survey

OBJECTIVE

Alterations in the microbiome, including the periodontal microbiome, may be a risk factor for rheumatoid arthritis (RA). Most studies that have analyzed this association are relatively small, focus primarily on a single periodontal pathogen (Porphyromonas gingivalis), and are not population based. This study was undertaken to investigate the association between elevated serum levels of IgG antibodies to 19 periodontal species and the prevalence of rheumatoid factor (RF) in a large nationally representative sample of adults.

METHODS

The Third National Health and Nutrition Examination Survey (NHANES-III) is a cross-sectional sample of the noninstitutionalized US population (n = 33,994). Our study population included all dentate participants who were 60 years and older, did not have RA as defined by a modified version of the American College of Rheumatology 1987 criteria, and had complete data for both serum IgG antibodies against periodontal bacteria and serum RF antibody titer (n = 2,461).

RESULTS

Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) summarizing the relationship between the 19 periodontal serum IgG antibodies and RF seropositivity ranged from 0.53 (95% CI 0.29-0.97) to 1.27 (95% CI 0.79-2.06), and 17 of the 19 observed ORs were <1.0. The ORs for RF seropositivity among participants with elevated Prevotella intermedia (0.53 [95% CI 0.29-0.97]) and Capnocytophaga ochracea (0.54 [0.31-0.95]) IgG levels were statistically significant.

CONCLUSION

Our findings indicate that elevated levels of IgG antibodies to periodontal bacteria are mostly unassociated with RF seropositivity in the nationally representative NHANES-III. Elevated levels of antibodies to P intermedia and C ochracea are associated with lower odds of RF seropositivity.

Two rheumatoid arthritis-specific autoantigens correlate microbial immunity with autoimmune responses in joints

In rheumatoid arthritis (RA), immunological triggers at mucosal sites, such as the gut microbiota, may promote autoimmunity that affects joints. Here, we used discovery-based proteomics to detect HLA-DR-presented peptides in synovia or peripheral blood mononuclear cells and identified 2 autoantigens, N-acetylglucosamine-6-sulfatase (GNS) and filamin A (FLNA), as targets of T and B cell responses in 52% and 56% of RA patients, respectively. Both GNS and FLNA were highly expressed in synovia. GNS appeared to be citrullinated, and GNS antibody values correlated with anti-citrullinated protein antibody (ACPA) levels. FLNA did not show the same results. The HLA-DR-presented GNS peptide has marked sequence homology with epitopes from sulfatase proteins of the Prevotella sp. and Parabacteroides sp., whereas the HLA-DR-presented FLNA peptide has homology with epitopes from proteins of the Prevotella sp. and Butyricimonas sp., another gut commensal. Patients with T cell reactivity with each self-peptide also had responses to the corresponding microbial peptides, and the levels were directly correlated. Furthermore, HLA-DR molecules encoded by shared-epitope (SE) alleles were predicted to bind these self- and microbial peptides strongly, and these responses were more common in RA patients with SE alleles. Thus, sequence homology between T cell epitopes of 2 self-proteins and a related order of gut microbes may provide a link between mucosal and joint immunity in patients with RA.

Evidence of the Immune Relevance of Prevotella copri, a Gut Microbe, in Patients With Rheumatoid Arthritis

OBJECTIVE

Prevotella copri, an intestinal microbe, may overexpand in stool samples from patients with new-onset rheumatoid arthritis (RA), but it is not yet clear whether the organism has immune relevance in RA pathogenesis.

METHODS

HLA-DR-presented peptides (T cell epitopes) from P copri were sought directly in the patients' synovial tissue or peripheral blood mononuclear cell (PBMC) samples using tandem mass spectrometry. The antigenicity of peptides or their source proteins was examined in samples from the RA patients or comparison groups. T cell reactivity was determined by enzyme-linked immunospot assay; antibody responses were measured by enzyme-linked immunosorbent assay, and cytokine/chemokine determinations were made by bead-based assays. Serum and synovial fluid samples were examined for 16S ribosomal DNA for P copri using nested polymerase chain reaction analysis.

RESULTS

In PBMCs, we identified an HLA-DR-presented peptide from a 27-kd protein of P copri (Pc-p27), which stimulated Th1 responses in 42% of patients with new-onset RA. In both new-onset RA patients and chronic RA patients, 1 subgroup had IgA antibody responses to either Pc-p27 or the whole organism, which correlated with Th17 cytokine responses and frequent anti-citrullinated protein antibodies (ACPAs). The other subgroup had IgG P copri antibodies, which were associated with Prevotella DNA in synovial fluid, P copri-specific Th1 responses, and less frequent ACPAs. In contrast, P copri antibody responses were rarely found in patients with other rheumatic diseases or in healthy controls.

CONCLUSION

Subgroups of RA patients have differential IgG or IgA immune reactivity with P copri, which appears to be specific for this disease. These observations provide evidence that P copri is immune-relevant in RA pathogenesis.

Decision Making in the Treatment of Patients With Rheumatoid Arthritis and Periodontitis: Scientific Evidence and Clinical Experience

Focused Clinical Question: What are the key considerations for coordination of care for a patient with rheumatoid arthritis (RA) and chronic periodontitis (CP), and what are the clinical implications of RA on periodontal health? Summary: Both RA and CP involve hyper-immune response and osseous destruction. However, despite emerging evidence that RA and CP may have common etiologies and patients with RA have increased risk of CP, periodontal evaluation and treatment remain largely similar for patients with and without RA. More fully assessing inflammatory burden in patients with RA and CP may allow practitioners to more accurately assess the risk profile of a patient for RA and periodontal disease progression and to better evaluate adequate end points to periodontal therapy. Furthermore, coordination of care for patients with RA and CP with their rheumatologist or treating physician could allow for advanced screening and prophylactic care that may prevent disease development or progression. Conclusion: For patients with RA and CP, evaluation of their rheumatoid disease activity score and periodontal inflamed surface area score, rather than traditional periodontal clinical measurements, along with additional biologic sampling methods may be appropriate measures to more accurately assess inflammatory burden in these susceptible patients.

Periodontitis is associated with rheumatoid arthritis: a study with longstanding rheumatoid arthritis patients in Korea

BACKGROUND/AIMS

A cross-sectional study was undertaken to investigate the association between severity of periodontitis and clinical manifestation of rheumatoid arthritis (RA).

METHODS

Two hundred sixty-four RA patients and 88 age- and sex-matched controls underwent dental exam. Additionally, clinical manifestations including disease activity and anti-citrullinated protein antibodies were evaluated in RA patients.

RESULTS

The prevalence of moderate or severe periodontitis was higher in RA patients compared to controls (63.6% vs 34.1%, p < 0.001). In markers of periodontal inflammation, bleeding on probing was correlated with disease activity score 28 (r = 0.128, p = 0.041), RA disease duration (r = 0.211, p = 0.001), erythrocyte sedimentation rate (ESR; r = 0.141, p = 0.023), anti-cyclic citrullinated peptide antibody (r = 0.183, p = 0.009), and anti-citrullinated α-enolase peptide-1 antibody (r = 0.143, p = 0.025). Gingival index was correlated with RA duration (r = 0.262, p < 0.001), ESR (r = 0.162, p = 0.009), anti-cyclic citrullinated peptide antibody (r = 0.203, p = 0.004) and anti-citrullinated α-enolase peptide-1 antibody (r = 0.225, p < 0.001). Periodontal structural damage represented by probing pocket depth and clinical attachment level were less in RA patients with human leukocyte antigen (HLA)-DRB1 shared epitope compared than those without shared epitope (p = 0.005 and p =0.006, respectively).

CONCLUSIONS

The prevalence of moderate or severe periodontitis was increased in RA patients compared to controls. Periodontal inflammation was correlated with RA disease duration, ESR, and anti-citrullinated protein antibodies. Periodontal structural damage was less in RA patients with HLA-DRB1 shared epitope.

Serum antibody levels against Porphyromonas gingivalis in patients with and without rheumatoid arthritis - a systematic review and meta-analysis

OBJECTIVES

Since the peptidyl arginine deiminase of Porphyromonas gingivalis is able to citrullinate peptides and proteins, various studies have suggested the species as a possible link between periodontal disease (PD) and rheumatoid arthritis (RA). This systematic review including meta-analysis was aimed to evaluate whether differences in terms of antibody titers against P. gingivalis exist between RA patients and systemically healthy individuals with and without PD.

MATERIALS AND METHODS

The following focused question was addressed: Are the antibody titers against P. gingivalis of RA patients different from systemically healthy individuals with and without PD? A systematic data search was conducted in MEDLINE and EMBASE. The collected data underwent a meta-analysis to detect statistically significant differences in terms of antibody levels between the groups.

RESULTS

From 114 articles found by the search 13 articles met the inclusion criteria and provided data suitable for meta-analysis. After analyzing various levels of confinement the meta-analysis revealed a statistically significant higher antibody titer against P. gingivalis in patients suffering from RA in comparison with systemically and periodontally healthy controls (p < 0.01) and systemically healthy patients with PD (p < 0.01).

CONCLUSION

The present findings indicate that RA is often accompanied by the presence of an immune response against P. gingivalis.

CLINICAL RELEVANCE

The significantly higher antibody response to P. gingivalis in comparison to systemically healthy individuals supports the link between PD and RA by P. gingivalis. Screening of the regularly taken blood samples of RA patients for P. gingivalis antibodies may help to sensitize rheumatologists and RA patients for improving periodontal health.

Circulating secretory IgA antibodies against cyclic citrullinated peptides in early rheumatoid arthritis associate with inflammatory activity and smoking

Background

A possible association between mucosal immunization and inflammation, as well as the initiation and propagation of rheumatoid arthritis (RA), is attracting renewed interest. The aim of this study was to evaluate the possible occurrence and clinical correlations of circulating secretory immunoglobulin A (SIgA) antibodies against the second-generation cyclic citrullinated peptides (CCP) among patients with recent-onset RA followed prospectively over 3 years.

Methods

Baseline serum samples from 636 patients with recent-onset RA were analyzed for SIgA anti-CCP antibodies by using an enzyme-linked immunosorbent assay with a secondary antibody directed against secretory component. SIgA anti-CCP status at baseline was analyzed in relation to smoking, HLA-DRB1/shared epitope (SE), and the disease course over 3 years. Significant findings were evaluated in regression analysis that included age, sex, smoking, and SE.

Results

Seventeen percent of the patients tested positive for circulating SIgA anti-CCP, and the occurrence was confirmed by detection of secretory component in an affinity-purified IgA anti-CCP fraction. SIgA anti-CCP positivity at baseline was associated with slightly higher baseline erythrocyte sedimentation rate (ESR) (mean 38 vs. 31 mm/first hour, p = 0.004) and C-reactive protein (CRP) (mean 30 vs. 23 mg/L, p = 0.047). During follow-up, SIgA anti-CCP-positive patients had a higher mean AUC regarding ESR (adjusted p = 0.003), although there were no significant differences regarding CRP, tender and swollen joint counts, or radiological joint damage (median Larsen progression 1.0 vs. 1.0, p = 0.22). SIgA anti-CCP was associated significantly with smoking (79 % ever smokers among SIgA anti-CCP-positive patients vs. 59 % in SIgA anti-CCP-negative patients, adjusted OR 2.19, 95 % CI 1.01–4.37, p = 0.027) but not with carriage of the SE (80 % vs. 73 %, p = 0.62).

Conclusions

Circulating SIgA anti-CCP, which is present in a subgroup of patients with early RA, is not related to SE, but it is environmentally linked to cigarette smoking. This finding strengthens the hypothesis that immunization against citrullinated peptides and/or proteins may occur at mucosal surfaces of the airways. Analysis of SIgA antibodies in serum may be a convenient and more versatile means to investigate the “mucosal connection” in RA compared with analyses in mucosal fluid samples.

Understanding the role of cytokines in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease of unknown etiology. It is characterized by the presence of rheumatoid factor and anti-citrullinated peptide antibodies. Initial phase of RA involves the activation of both T and B cells. Cytokines have a crucial role in the pathophysiology of RA as pro-inflammatory cytokines such as TNFα, IL-1, IL-17 stimulates inflammation and degradation of bone and cartilage. There occurs an imbalance between the pro- and anti-inflammatory cytokine activities which leads to multisystem immune complications. There occurs a decline in the number of Treg cells which may also play an important role in pathophysiology of the disease. In RA patients, serum or plasma level of cytokines may indicate the severity of disease. Cytokine gene polymorphism could be used as markers of susceptibility and severity of RA. Anti-cytokine agents seem to emerge as potent drug molecules to treat RA. Many clinical trials are ongoing and several positive results have been obtained. There is a need to develop potential anti-cytokine agents that target numerous pathways involved in the pathogenesis of RA. This review article describes the effector functions of pro- and anti-inflammatory cytokines and the role of cytokine gene polymorphism in the pathogenesis of RA. Anti-cytokine agents that are currently available and those that are still in clinical trials have also been summarized.

Does Treatment of Periodontal Disease Influence Systemic Disease?

Periodontal diseases are the most common human diseases globally, with gingivitis affecting up to 90% and periodontitis affecting 50% of adults. Tooth enamel is the only nonshedding tissue in the human body. In the absence of proper oral hygiene measures, microbial biofilm (dental plaque) develops on the teeth to include more than 700 different bacterial species, along with viruses, fungi, archea, and parasites. With time, ecological imbalances promote the growth of selected commensal species that induce host inflammatory pathways resulting in tissue destruction, including ulceration of the periodontal epithelium.

Periodontal disease and subgingival microbiota as contributors for rheumatoid arthritis pathogenesis: modifiable risk factors?

PURPOSE OF REVIEW

Since the early 1900s, the role of periodontal disease in the pathogenesis of rheumatoid arthritis has been a matter of intense research. The last decade has witnessed many advances supporting a link between periodontitis, the presence of specific bacterial species (i.e. Porphyromonas gingivalis) and their effects in immune response. This review will examine available evidence on the individuals.

RECENT FINDINGS

Epidemiological studies have stressed the commonalities shared by periodontal disease and rheumatoid arthritis. Many groups have focused their attention toward understanding the periodontal microbiota and its alterations in states of health and disease. The presence of circulating antibodies against periodontopathic bacteria and associated inflammatory response has been found in both rheumatoid arthritis (RA) patients and individuals at-risk for disease development. Most recently, the periodontal microbiota of smokers and patients with RA has been elucidated, revealing profound changes in the bacterial communities compared with those of healthy controls. This has led to several small clinical trials of progressive disease treatment as adjuvant for disease-modifying therapy in RA.

SUMMARY

Smoking and periodontal disease are emerging risk factors for the development of RA. Epidemiological, clinical, and basic research has further strengthened this association, pointing toward changes in the oral microbiota as possible contributors to systemic inflammation and arthritis.

Anti-HmuY antibodies specifically recognize Porphyromonas gingivalis HmuY protein but not homologous proteins in other periodontopathogens

Given the emerging evidence of an association between periodontal infections and systemic conditions, the search for specific methods to detect the presence of P. gingivalis, a principal etiologic agent in chronic periodontitis, is of high importance. The aim of this study was to characterize antibodies raised against purified P. gingivalis HmuY protein and selected epitopes of the HmuY molecule. Since other periodontopathogens produce homologs of HmuY, we also aimed to characterize responses of antibodies raised against the HmuY protein or its epitopes to the closest homologous proteins from Prevotella intermedia and Tannerella forsythia. Rabbits were immunized with purified HmuY protein or three synthetic, KLH-conjugated peptides, derived from the P. gingivalis HmuY protein. The reactivity of anti-HmuY antibodies with purified proteins or bacteria was determined using Western blotting and ELISA assay. First, we found homologs of P. gingivalis HmuY in P. intermedia (PinO and PinA proteins) and T. forsythia (Tfo protein) and identified corrected nucleotide and amino acid sequences of Tfo. All proteins were overexpressed in E. coli and purified using ion-exchange chromatography, hydrophobic chromatography and gel filtration. We demonstrated that antibodies raised against P. gingivalis HmuY are highly specific to purified HmuY protein and HmuY attached to P. gingivalis cells. No reactivity between P. intermedia and T. forsythia or between purified HmuY homologs from these bacteria and anti-HmuY antibodies was detected. The results obtained in this study demonstrate that P. gingivalis HmuY protein may serve as an antigen for specific determination of serum antibodies raised against this bacterium.