Association between anti-Porphyromonas gingivalis or anti-α-enolase antibody and severity of periodontitis or rheumatoid arthritis (RA) disease activity in RA

Molecular mimicry in the pathogenesis of autoimmune rheumatic diseases

Autoimmune rheumatic diseases (ARDs) are a heterogeneous group of conditions characterized by excessive and misdirected immune responses against the body's own musculoskeletal tissues. Their exact aetiology remains unclear, with genetic, demographic, behavioural and environmental factors implicated in disease onset. One prominent hypothesis for the initial breach of immune tolerance (leading to autoimmunity) is molecular mimicry, which describes structural or sequence similarities between human and microbial proteins (mimotopes). This similarity can lead to cross-reactive antibodies and T-cell receptors, resulting in an immune response against autoantigens. Both commensal microbes in the human microbiome and pathogens can trigger molecular mimicry, thereby potentially contributing to the onset of ARDs. In this review, we focus on the role of molecular mimicry in the onset of rheumatoid arthritis and systemic lupus erythematosus. Moreover, implications of molecular mimicry are also briefly discussed for ankylosing spondylitis, systemic sclerosis and myositis.

Immunological landscape of periodontitis and rheumatoid arthritis and their molecular crosstalk

BACKGROUND

The association between periodontitis (PT) and rheumatoid arthritis (RA) is well-established; however, the molecular mechanisms underlying this relationship remain poorly understood. This study aims to delineate shared genetic and molecular features between PT and RA to uncover potential common pathways involved in their pathogenesis.

METHODS

Gene expression data sets for PT and RA were retrieved from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) and co-expressed gene modules were identified using weighted gene co-expression network analysis (WGCNA) and the DESeq2 package. Enrichment analyses, including KEGG and Gene Ontology (GO) pathways, as well as immune cell infiltration profiling, were performed to explore shared biological pathways. A protein-protein interaction (PPI) network was constructed to pinpoint key genes linking PT and RA. Functional assays were conducted by overexpressing the identified core gene, PTPRC, in MH7A cells via lentiviral transfection, followed by cell viability (CCK-8), migration, and invasion assays. In addition, transcription factor enrichment and connectivity map (cMAP) analyses were employed to identify common transcriptional regulators and potential therapeutic targets for both conditions.

RESULTS

WGCNA and DESeq2 analyses revealed 154 shared DEGs between PT and RA, predominantly enriched in immune and inflammatory response pathways. PTPRC emerged as a pivotal shared gene, exhibiting significantly higher expression in PT patients compared to controls. In vitro assays confirmed that PTPRC overexpression enhanced fibroblast proliferation, migration, and invasion. Furthermore, transcription factor enrichment analysis and cMAP identified overlapping transcriptional regulators and potential pharmacological agents for both diseases.

CONCLUSIONS

This study provides novel insights into shared gene expression profiles and molecular mechanisms linking PT and RA, identifying PTPRC as a potential key regulator. These findings suggest that targeting PTPRC could offer therapeutic opportunities for RA driven by PT.

Systemic Factors Affecting Prognosis and Outcomes in Periodontal Disease

This review delves into the effects of autoimmune conditions like rheumatoid arthritis, inflammatory disorders such as irritable bowel syndrome, cardiovascular disease, diabetes, infectious ailments like human immunodeficiency virus, and their medications on periodontal therapy outcomes. It also explores the influence of hormones. Understanding these systemic factors is crucial for optimizing periodontal health and treatment efficacy. The review underscores the necessity of considering these variables in periodontal care. Other vital systemic factors are addressed elsewhere in this special edition.

Higher odds of periodontitis in systemic lupus erythematosus compared to controls and rheumatoid arthritis: a systematic review, meta-analysis and network meta-analysis

Introduction

Periodontitis as a comorbidity in systemic lupus erythematosus (SLE) is still not well recognized in the dental and rheumatology communities. A meta-analysis and network meta-analysis were thus performed to compare the (i) prevalence of periodontitis in SLE patients compared to those with rheumatoid arthritis (RA) and (ii) odds of developing periodontitis in controls, RA, and SLE.

Methods

Pooled prevalence of and odds ratio (OR) for periodontitis were compared using meta-analysis and network meta-analysis (NMA).

Results

Forty-three observational studies involving 7,800 SLE patients, 49,388 RA patients, and 766,323 controls were included in this meta-analysis. The pooled prevalence of periodontitis in SLE patients (67.0%, 95% confidence interval [CI] 57.0-77.0%) was comparable to that of RA (65%, 95% CI 55.0-75.0%) (p>0.05). Compared to controls, patients with SLE (OR=2.64, 95% CI 1.24-5.62, p<0.01) and RA (OR=1.81, 95% CI 1.25-2.64, p<0.01) were more likely to have periodontitis. Indirect comparisons through the NMA demonstrated that the odds of having periodontitis in SLE was 1.49 times higher compared to RA (OR=1.49, 95% CI 1.09-2.05, p<0.05).

Discussion

Given that RA is the autoimmune disease classically associated with periodontal disease, the higher odds of having periodontitis in SLE are striking. These results highlight the importance of addressing the dental health needs of patients with SLE.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/ identifier CRD42021272876.

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.

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.

Impacts of Porphyromonas gingivalis periodontitis on rheumatoid arthritis autoimmunity

In RA patients' synovial sites, citrullinated RA-related antigens such as type II collagens, fibrin (ogen), vimentin, and α-enolase could be targeted by ACCPAs. Since ACCPA production can be initiated a long time before RA sign appearance, primary auto-immunization against these citrullinated proteins can be originated from extra-articular sites. It has been shown that there is a significant association between P. gingivalis periodontitis, anti- P. gingivalis antibodies, and RA. P. gingivalis gingipains (Rgp, Kgp) can degrade proteins such as fibrin and α-enolase into some peptides in the form of Arg in the C-terminal which is converted to citrulline by PPAD. Also, PPAD can citrullinate type II collagen and vimentins (SA antigen). P. gingivalis induces inflammation and chemoattraction of immune cells such as neutrophils and macrophages through the increase of C5a (gingipain C5 convertase-like activity) and SCFA secretion. Besides, this microorganism stimulates anoikis, a special type of apoptosis, and NETosis, an antimicrobial form of neutrophil death, leading to the release of PAD1-4, α-enolase, and vimentin from apoptotic cells into the periodontal site. In addition, gingipains can degrade macrophages CD14 and decrease their ability in apoptotic cell removal. Gingipains also can cleave IgGs in the Fc region and transform them into rheumatoid factor (RF) antigens. In the present study, the effects of P. gingivalis on rheumatoid arthritis autoimmune response have been reviewed, which could attract practical insight both in bench and clinic.

The role of IL-31 and IL-34 in the diagnosis and treatment of chronic periodontitis

This study was devoted to demonstrating the role of IL-31 and IL-34 in the diagnosis and treatment of chronic periodontitis (CP). From the results, we found that the IL-31 and IL-34 levels were significantly increased in GCF and serum of CP patients compared with healthy controls or obese patients. Meanwhile, the area under the curve results further verified the diagnostic potential of IL-31 and IL-34 in terms of discriminating CP from obese patients at the GCF and serum levels. Finally, after 1 year of continuous treatment, we found that IL-31 and IL-34 levels were decreased in CP, suggesting their potential as biomarkers in CP treatment response. Monitoring GCF and serum levels of IL-31 and IL-34 contributed to CP detection and treatment response.

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.

Gut Microbial Antigenic Mimicry in Autoimmunity

The gut microbiota plays a major role in the developmental biology and homeostasis of cells belonging to the adaptive and innate arms of the immune system. Alterations in its composition, which are known to be regulated by both genetic and environmental factors, can either promote or suppress the pathogenic processes underlying the development of various autoimmune diseases, including inflammatory bowel disease, multiple sclerosis, systemic lupus erythematosus, type 1 diabetes and rheumatoid arthritis, to just name a few. Cross-recognition of gut microbial antigens by autoreactive T cells as well as gut microbe-driven alterations in the activation and homeostasis of effector and regulatory T cells have been implicated in this process. Here, we summarize our current understanding of the positive and negative associations between alterations in the composition of the gut microbiota and the development of various autoimmune disorders, with a special emphasis on antigenic mimicry.

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.

Effects of nonsurgical periodontal therapy in patients with rheumatoid arthritis: a prospective before and after study

Background

periodontal therapy has been suggested to have systemic effects. However, studies of periodontal therapy in rheumatoid arthritis patients have produced controversial results.

Aim

To compare the effects of nonsurgical periodontal therapy on biochemical markers of rheumatoid arthritis and periodontal parameters in patients with and without rheumatoid arthritis.

Methods

a prospective before-and-after study was conducted that included 21 participants without and 29 participants with rheumatoid arthritis. Periodontal parameters, Porphyromonas gingivalis detection, C-reactive protein, rheumatoid factor and anti-citrullinated protein antibodies were measured at baseline and three months after nonsurgical periodontal therapy and the changes were statistically assessed.

Results

In general, both groups presented statistically significant improvement in periodontal parameters (p<0.05). There was an increase in the counts of P. gingivalis in both groups at three months. In addition, there was a reduction in levels of anti-citrullinated protein antibodies and rheumatoid factor in participants with rheumatoid arthritis. In contrast, C-reactive protein levels increased in both groups but were higher in the rheumatoid arthritis group. Periodontal parameters in rheumatoid arthritis participants under disease-modifying antirheumatic drugs presented a slightly higher improvement (p <0.05).

Conclusions

Nonsurgical periodontal therapy has similar improvements in periodontal parameters in patients with and without rheumatoid arthritis. In addition, nonsurgical periodontal therapy may benefit serum levels of anti-citrullinated protein antibodies and rheumatoid factors in patients with rheumatoid arthritis. NCT04658615.

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

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

Evaluation of systemic lupus erythematosus disease activity using anti-α-enolase antibody and RDW

The objective of the study was to investigate the value of anti-α-enolase antibody (Ab) combined with RDW in evaluating the activity of systemic lupus erythematosus (SLE). Levels of serum anti-α-enolase Ab and RDW were detected in 193 SLE patients and 98 healthy controls by ELISA and automatic blood cell counter (XN9000), respectively. Furthermore, the correlation between anti-α-enolase Ab and RDW in evaluating the activity of SLE was evaluated by correlation analysis. The level of anti-α-enolase Ab (9.16 ± 0.44 ng/mL in stable group and 10.26 ± 0.36 ng/mL in activity group) was significantly higher than that in the healthy control (7.05 ± 0.27 ng/mL). The level of RDW (12.92% ± 1.23% in stable group and 13.57% ± 2.12% in activity group) was significantly higher than that in the healthy control (12.46% ± 0.61%). The levels of anti-α-enolase Ab or RDW in SLE patients were positively correlated with SLEDAI-2 K score (r= 0.75, r = 0.73), respectively. Compared with the anti-α-enolase Ab (AUC: 78.0%) or RDW (AUC:80.0%) alone, anti-α-enolase Ab combined with RDW (AUC: 81.0%) had the best of the effectiveness of evaluating activity of SLE. These data suggested that combined anti-α-enolase Ab with RDW might be good biomarker to predict the activity of SLE in clinical.

Rheumatoid arthritis risk in periodontitis patients: A systematic review and meta-analysis

OBJECTIVE

Many clinical studies have been carried out to investigate the relationship between periodontitis and rheumatoid arthritis (RA). Owing to limited evidence and inconsistent findings among these studies, it is unclear whether periodontitis would increase the risk for RA. This meta-analysis was performed to evaluate whether periodontitis represents a risk factor for RA.

METHODS

PubMed, Cochrane Library, Embase, Web of Science, and Wanfang were searched for eligible studies that compared periodontitis patients with controls. A pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to assess the association between periodontitis and RA.

RESULTS

Thirteen studies including a total of 706611 periodontitis patients and 349983 control subjects were included. The pooled OR of RA risk between periodontitis and controls was (OR: 1.69; 95% CI: 1.31-2.17; P<0.0001), indicating that the patients in periodontitis group had a 69% greater risk for RA than people in control group. When stratified by disease type, the pooled results showed periodontitis represents a risk factor for incident RA (OR=1.70, 95%CI: 0.75-3.85, P<0.001) and mixed RA (OR=1.61, 95%CI: 1.26-2.06; P<0.001). When stratified by disease duration, the pooled results showed periodontitis represents a risk factor for RA disease duration>5 years (OR=2.88, 95%CI: 0.66-12.62, P=0.018), disease duration<5 years (OR=2.59, 95%CI: 0.83-8.11, P<0.001), mixed disease duration (OR=1.53; 95%CI: 1.05-2.22, P<0.001).

CONCLUSION

Our meta-analysis revealed an increased risk of RA in patients with periodontitis compared to healthy controls. Moreover, when stratified by disease type, there was a higher risk between incident RA and periodontitis. When stratified by disease duration, the patients with periodontitis might be more closely associated with the RA patients with disease duration >5 years.

Neutrophil Extracellular Traps in Periodontitis

Neutrophils are key cells of the immune system and have a decisive role in fighting foreign pathogens in infectious diseases. Neutrophil extracellular traps (NETs) consist of a mesh of DNA enclosing antimicrobial peptides and histones that are released into extracellular space following neutrophil response to a wide range of stimuli, such as pathogens, host-derived mediators and drugs. Neutrophils can remain functional after NET formation and are important for periodontal homeostasis. Periodontitis is an inflammatory multifactorial disease caused by a dysbiosis state between the gingival microbiome and the immune response of the host. The pathogenesis of periodontitis includes an immune-inflammatory component in which impaired NET formation and/or elimination can be involved, contributing to an exacerbated inflammatory reaction and to the destruction of gingival tissue. In this review, we summarize the current knowledge about the role of NETs in the pathogenesis of periodontitis.

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.

Association between periodontitis and anti-citrullinated protein antibodies in rheumatoid arthritis patients: a cross-sectional study

AIM

The aim of this study was to evaluate the association between periodontal parameters related with the periodontal disease severity and the presence and levels of anti-citrullinated protein antibodies (ACPAs) in rheumatoid arthritis (RA) patients.

MATERIALS AND METHODS

This cross-sectional study included 164 RA patients. Socio-demographics and RA disease characteristics, including ELISA-detected ACPA (anti-CCP-2), were recorded. Exposure was assessed by periodontal parameters: plaque index (PI), bleeding on probing (BoP), probing pocket depth, and clinical attachment levels (CAL). Presence and levels of ACPAs (outcome) and exposure variables were compared by both parametric and non-parametric tests and associations were evaluated by adjusted odds ratio (OR).

RESULTS

A significant association was observed between the presence of anti-CCP antibodies and severity of periodontal outcomes such as the mean CAL (OR 1.483, p = 0.036), mean PI (OR 1.029, p = 0.012), and the number of pockets ≥ 5 mm (OR 1.021, p = 0.08). High anti-CCP antibodies levels were associated with mean CAL, mean PI, and number of pockets ≥ 5 mm with an OR of 1.593 (p = 0.043), 1.060 (p <  0.001), and 1.031 (p = 0.031), respectively. Furthermore, a significant increase of 4.45 U/mL in anti-CCP antibodies levels (p = 0.002) in RA patients was found for each pocket ≥ 5 mm after adjusting for age, gender, smoking, time of disease evolution, and RA activity.

CONCLUSIONS

In RA patients, the severity of periodontal conditions such as mean CAL, mean PI, and the number of pockets ≥ 5 mm were linearly associated with both the presence and levels of anti-CCP antibodies.

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.

Treponema denticola enolase contributes to the production of antibodies against ENO1 but not to the progression of periodontitis

Autoantibodies against alpha-enolase (ENO1) are often detected in various infectious and autoimmune diseases. Anti-ENO1 antibody titers were reported to be associated with the severity of periodontitis in patients with rheumatoid arthritis. Because the enolase of the periodontal pathogen Treponema denticola (TdEno) has the highest homology with ENO1 among the enolases of human-associated bacteria, we hypothesized that anti-ENO1 autoantibodies produced during the immune response to TdEno may contribute to the progression of periodontitis and tested it in human and mouse systems. In human subjects with healthy periodontium or chronic periodontitis, a strong positive correlation between the levels of anti-TdEno and anti-ENO1 antibodies was observed. In addition, the purified anti-TdEno antibodies recognized ENO1 as well as TdEno in a dot blot, confirming the cross-reactivity between TdEno and ENO1. However, anti-ENO1 antibody titers were not associated with the severity of periodontitis. To further investigate the role of TdEno in the production of anti-ENO1 antibodies and the progression of periodontitis, mice received an oral gavage of P. gingivalis alone, subcutaneous immunization with TdEno alone, or both P. gingivalis oral gavage and TdEno immunization. Immunization with TdEno induced not only anti-TdEno but also anti-mouse Eno1 (mEno1) antibodies and increased the expression of TNFα in the gingival tissues. However, alveolar bone loss was not increased by TdEno immunization. In conclusion, autoreactive anti-ENO1/mEno1 antibodies that are produced as byproducts during the antibody response to TdEno play a minimal role in the progression of periodontitis in the absence of rheumatoid arthritis.

Association between severity of periodontitis and clinical activity in rheumatoid arthritis patients: a case-control study

Background

A high prevalence of periodontitis has been reported in rheumatoid arthritis (RA) patients, although the strength of this association, its temporal link and the possible relationship between the severity of periodontitis and RA disease activity remain unclear. The objective of this work was to investigate whether periodontitis is associated with RA and whether periodontitis severity is linked to RA disease activity.

Methods

This case–control study included 187 patients diagnosed with RA and 157 control patients without inflammatory joint disease. RA disease activity and severity were evaluated by the Disease Activity Score 28, the Simplified Disease Activity Index, the Clinical Disease Activity Index, rheumatoid factor, anti-citrullinated protein antibody titers, the erythrocyte sedimentation rate, C-reactive protein, presence of extra-articular manifestations and type of RA therapy. Exposure severity was assessed by the following periodontal parameters: plaque index, bleeding on probing, probing pocket depth and clinical attachment levels. Sociodemographic variables and comorbidities were evaluated as confounding variables. Outcome and exposure variables were compared by both parametric and nonparametric tests, and possible associations were assessed through regression analysis with a calculation for the adjusted odds ratio (OR).

Results

A significant association was demonstrated between periodontitis and RA with an adjusted OR of 20.57 (95% CI 6.02–70.27, p < 0.001). Compared with controls, all parameters related to periodontal status (plaque index, bleeding on probing, probing pocket depth and clinical attachment levels) were significantly worse in RA patients (p < 0.001). Periodontitis severity was significantly associated with RA disease activity (p < 0.001), showing in an ordinal logistic regression model an association between periodontal severity and disease activity with an adjusted OR of 2.66 (95% CI 1.24–5.74, p = 0.012).

Conclusion

A significant association was demonstrated between periodontitis and RA, independent of other confounders. This association was more evident in patients with pronounced periodontal disease and higher RA disease activity.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1808-z) contains supplementary material, which is available to authorized users.

Periodontal pathogens and the association between periodontitis and rheumatoid arthritis in Korean adults

Purpose

Periodontitis and rheumatoid arthritis (RA) share a similar inflammatory pathogenesis. Porphyromonas gingivalis (Pg) can induce anticyclic-citrullinated peptide autoantibodies (anti-CCP antibodies), a key factor in the development of RA. This study aimed at evaluating the relationships between the 2 diseases and identifying the clinical implications thereof, with a focus on periodontal pathogens in Korean adults.

Methods

A total of 260 RA patients and 86 age- and sex-matched control patients without arthritis were enrolled in this prospective cross-sectional study. Periodontal indices and the prevalence and amount of periodontal pathogens were compared between the groups. Correlations between periodontal and RA indices were examined, as were correlations between 9 periodontal pathogens and RA indices.

Results

The RA group had significantly higher values than the control group for all investigated periodontal indices (P<0.05) except the number of teeth. The gingival index (GI) was correlated with the disease activity score 28 (DAS28) (r=0.125, P=0.049), RA disease duration (r=0.253, P<0.001), erythrocyte sedimentation rate (ESR) (r=0.162, P=0.010), and anti-CCP antibody titer (r=0.205, P=0.004). Probing pocket depth (PPD) was correlated with ESR (r=0.139, P=0.027) and anti-Pg antibody titer (r=0.203, P=0.001). Bleeding on probing (BOP) was correlated with DAS28 (r=0.137, P=0.030), RA disease duration (r=0.202, P=0.001), ESR (r=0.136, P=0.030), anti-Pg antibody titer (r=0.177, P=0.005), and anti-CCP antibody titer (r=0.188, P=0.007). Clinical attachment level (CAL) and periodontitis severity were correlated with anti-Pg antibody titer (the former r=0.201, P=0.002; the latter r=0.175, P=0.006). The quantity of Pg was positively correlated with the serum anti-Pg antibody titer (r=0.148, P=0.020).

Conclusions

The GI, BOP, and PPD showed positive relationships with several RA indices. The anti-Pg antibody titer had positive relationships with PPD, BOP, CAL, and periodontitis severity. Thus, increasing values of periodontal indices could be used as a risk indicator of disease development in RA patients, and an increasing anti-Pg antibody titer could be considered as a warning sign in RA patients suffering with periodontitis.

Distribution of Porphyromonas gingivalis fimA genotypes in patients affected by rheumatoid arthritis and periodontitis

OBJECTIVE

To determine and compare the distribution of Porphyromonas gingivalis fimA genotypes in patients affected by Rheumatoid arthritis (RA) and periodontitis (PE).

MATERIALS AND METHODS

This study involved 394 subjects divided into four groups, RA, PE, RA and PE and healthy subjects. PE was diagnosed by using clinical attachment loss (CAL) and probing depth (PD) indexes. Presence of P. gingivalis and its genotypes was identified by polymerase chain reaction in subgingival biofilm.

RESULTS

P. gingivalis was more frequent in patients with RA (82.69%), and fimA II genotype was the most frequent in all groups, especially in PE/RA (76.71%). There was statistical difference (p < .05) regarding the frequency of P. gingivalis genotypes such as fimA Ib, II and III.

CONCLUSIONS

Distribution of P. gingivalis fimA II genotypes was different among groups, it could play a critical role in the presence of PE in RA patients.

No effects without causes: the Iron Dysregulation and Dormant Microbes hypothesis for chronic, inflammatory diseases

Since the successful conquest of many acute, communicable (infectious) diseases through the use of vaccines and antibiotics, the currently most prevalent diseases are chronic and progressive in nature, and are all accompanied by inflammation. These diseases include neurodegenerative (e.g. Alzheimer's, Parkinson's), vascular (e.g. atherosclerosis, pre-eclampsia, type 2 diabetes) and autoimmune (e.g. rheumatoid arthritis and multiple sclerosis) diseases that may appear to have little in common. In fact they all share significant features, in particular chronic inflammation and its attendant inflammatory cytokines. Such effects do not happen without underlying and initially 'external' causes, and it is of interest to seek these causes. Taking a systems approach, we argue that these causes include (i) stress-induced iron dysregulation, and (ii) its ability to awaken dormant, non-replicating microbes with which the host has become infected. Other external causes may be dietary. Such microbes are capable of shedding small, but functionally significant amounts of highly inflammagenic molecules such as lipopolysaccharide and lipoteichoic acid. Sequelae include significant coagulopathies, not least the recently discovered amyloidogenic clotting of blood, leading to cell death and the release of further inflammagens. The extensive evidence discussed here implies, as was found with ulcers, that almost all chronic, infectious diseases do in fact harbour a microbial component. What differs is simply the microbes and the anatomical location from and at which they exert damage. This analysis offers novel avenues for diagnosis and treatment.

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. 

Use of immunoproteomics to identify immunogenic proteins in a rat model of acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a common and life‑threatening clinical syndrome, and seeking biomarkers of ARDS has been an area of continuing research. The present study hypothesized that alterations to certain immunogenic substances occur in injured lungs and are able to specifically bind with corresponding proteins in the blood, and that these proteins may be readily detected. To investigate this hypothesis, a rat model of ARDS was established by cecal ligation and puncture surgery, and an immunoproteomics approach, using serum as the primary antibody in a western blot analysis, was used with the aim of identifying immunogenic proteins in the injured lungs. Ingenuity Pathway Analysis (IPA) was used for bioinformatics analysis, and mass spectrometric analysis was used to identify a total of 38 differentially expressed immunogenic proteins. Bioinformatics analysis revealed that the top canonical pathways in which the identified proteins may be involved were gluconeogenesis I, glycolysis I, choline degradation I, NADH repair and heme degradation. IPA Biomarker Filter analysis with the terms 'acute respiratory distress syndrome/acute lung injury' was used to screen 13 proteins as candidate biomarkers. These proteins were described as antigens, and suggested that paired antibodies may be detected in the plasma of patients at high risk of ARDS. Analysis of these identified proteins may provide novel insights into the potential pathological mechanisms of ARDS.

Salivary ammonia levels and Tannerella forsythia are associated with rheumatoid arthritis: A cross sectional study

The aim of this paper is to evaluate the relationship of salivary ammonium levels and the presence of bacteria with rheumatoid arthritis (RA) clinical disease activity in a cross-sectional study of Mexican patients. From a periodontal and disease activity standpoint, 132 consecutive RA patients fulfilling clinical criteria were evaluated. Ammonia levels (including peptidyl arginine deiminase activity) were evaluated by colorimetric assay and the presence of Porphyromonas gingivalis, Tannerella forsythia, and Prevotella intermedia was evaluated by polymerase chain reaction (PCR) technique. After a multivariate analysis, adjusting for clinical and serological parameters, a significant association was only observed between severe periodontitis and probing depth with high RA disease activity. Additionally, in contrast to P. gingivalis, the presence of T. forsythia was significantly associated with high disease RA activity even after multivariable adjustment analysis. There was also a significant increase in ammonium levels in the high RA activity group and a significant correlation between salivary ammonia and RA disease activity but not with autoantibody titers. Similarly, we observed a significant increase in the ammonium levels derived from the cultures of P. gingivalis and T. forsythia, with respect to P. intermedia and S. gordonii cultures, or even healthy donors. These results suggest that RA activity is associated with severe periodontitis, high salivary ammonium levels and the presence of T. forsythia.

Biomarkers to guide clinical therapeutics in rheumatology?

PURPOSE OF REVIEW

The use of biomarkers in rheumatology can help identify disease risk, improve diagnosis and prognosis, target therapy, assess response to treatment, and further our understanding of the underlying pathogenesis of disease. Here, we discuss the recent advances in biomarkers for rheumatic disorders, existing impediments to progress in this field, and the potential of biomarkers to enable precision medicine and thereby transform rheumatology.

RECENT FINDINGS

Although significant challenges remain, progress continues to be made in biomarker discovery and development for rheumatic diseases. The use of next-generation technologies, including large-scale sequencing, proteomic technologies, metabolomic technologies, mass cytometry, and other single-cell analysis and multianalyte analysis technologies, has yielded a slew of new candidate biomarkers. Nevertheless, these biomarkers still require rigorous validation and have yet to make their way into clinical practice and therapeutic development. This review focuses on advances in the biomarker field in the last 12 months as well as the challenges that remain.

SUMMARY

Better biomarkers, ideally mechanistic ones, are needed to guide clinical decision making in rheumatology. Although the use of next-generation techniques for biomarker discovery is making headway, it is imperative that the roadblocks in our search for new biomarkers are overcome to enable identification of biomarkers with greater diagnostic and predictive utility. Identification of biomarkers with robust diagnostic and predictive utility would enable precision medicine in rheumatology.

Cross-Sectional Evaluation of Periodontal Status and Microbiologic and Rheumatoid Parameters in a Large Cohort of Patients With Rheumatoid Arthritis

BACKGROUND

This study evaluates periodontal conditions and microbiologic findings and their influence on rheumatologic disease parameters in patients with rheumatoid arthritis (RA).

METHODS

One hundred and sixty-eight patients with RA were included. A healthy control group (HC, n = 168) was composed according to age, sex, and smoking habits. Rheumatologic data (duration of illness, Disease Activity Score 28, rheumatic factor [RF], anti-cyclic citrullinated peptide [aCCP], medications) were extracted from patients' records. Dental examination included: 1) dental findings (decayed, missing, and/or filled adult teeth [DMF-T] index); 2) gingival inflammation (papillary bleeding index [PBI]); and 3) periodontal status (probing depth [PD], attachment loss [AL]). Periodontal condition was classified as healthy/mild, moderate, or severe periodontitis. Subgingival biofilm was analyzed regarding 11 periodontopathogenic bacteria. Statistical analyses included: 1) Kolmogorov-Smirnov test; 2) Mann-Whitney U test; 3) Pearson χ² test; 4) Kruskal-Wallis test; and 5) regression analysis; level of significance α = 5%.

RESULTS

Mean DMF-T was significantly higher in patients with RA (19.3 ± 4.8) than in HC group (16.9 ± 5.8), especially owing to number of missing teeth (RA = 6.0 ± 5.4, HC = 3.1 ± 3.3; P <0.01). Patients with RA had a significantly higher proportion of increased PD (P <0.01) and AL compared with HC group (P <0.01). Moderate to severe periodontitis was noted in 98% of patients with RA and 82% of the HC group (P <0.01). RF-positive patients with RA suffered from worse periodontal conditions than RF-negative patients (P = 0.01). Age, PBI, and presence of Treponema denticola (P <0.03) are related to periodontal condition in patients with RA. Although not statistically significant, Porphyromonas gingivalis and Fusobacterium nucleatum occur in higher concentrations more often in aCCP-positive patients with RA (P = 0.06).

CONCLUSIONS

Patients with RA had worse periodontal conditions than HC participants. Although a trend for higher F. nucleatum and P. gingivalis concentrations in aCCP-positive patients with RA was found, importance of periodontal pathogenic bacteria and rheumatoid parameters in the interrelationship between periodontitis and RA remains unclear.

NETosis as Source of Autoantigens in Rheumatoid Arthritis

In neutrophils (but also in eosinophils and in mast cells), different inflammatory stimuli induce histone deimination, chromatin decondensation, and NET formation. These web-like structures that trap and kill microbes contain DNA, cationic granule proteins, and antimicrobial peptides, but the most abundant proteins are core histones. Histones contained in NETs have been deiminated, and arginines are converted in citrullines. While deimination is a physiological process amplified in inflammatory conditions, only individuals carrying genetic predisposition to develop rheumatoid arthritis (RA) make antibodies to deiminated proteins. These antibodies, collectively identified as anti-citrullinated proteins/peptides antibodies (ACPA), react with different deiminated proteins and display partially overlapping specificities. In this paper, we will summarize current evidence supporting the role of NETosis as critical mechanism in the breach of tolerance to self-antigens and in supporting expansion and differentiation of autoreactive cells. In fact, several lines of evidence connect NETosis with RA: RA unstimulated synovial fluid neutrophils display enhanced NETosis; sera from RA patients with Felty's syndrome bind deiminated H3 and NETs; a high number of RA sera bind deiminated H4 contained in NETs; human monoclonal antibodies generated from RA synovial B cells decorate NETs and bind deiminated histones. In RA, NETs represent on one side an important source of autoantigens bearing posttranslational modifications and fueling the production of ACPA. On the other side, NETs deliver signals that maintain an inflammatory milieu and contribute to the expansion and differentiation of ACPA-producing B cells.

Single cell cloning and recombinant monoclonal antibodies generation from RA synovial B cells reveal frequent targeting of citrullinated histones of NETs

OBJECTIVES

Rheumatoid arthritis (RA) is characterised by breach of self-tolerance towards citrullinated antigens with generation of anti-citrullinated peptide/proteins antibodies (ACPA). Currently, the nature and source of citrullinated antigens driving the humoral autoimmune response within synovial ectopic lymphoid structures (ELS) is a crucial unknown aspect of RA pathogenesis. Here we characterised the autoreactive B-cell response of lesional B cells isolated from ELS+RA synovium.

METHODS

Single synovial tissue CD19+cells were Fluorescence Activated Cell Sorting (FACS)-sorted and VH/VL Ig genes cloned to generate recombinant monoclonal antibodies (rmAbs) from patients with ELS+/ACPA+RA.

RESULTS

RA-rmAbs immunoreactivity analysis provided the following key findings: (1) in a chIP-based array containing 300 autoantigens and in a 'citrullinome' multiplex assay, a strong reactivity against citrullinated histones H2A/H2B (citH2A/H2B) was observed in ∼40% of RA-rmAbs, followed by cit-fibrinogen and cit-vimentin; (2) anti-citH2A/H2B-reactive RA-rmAbs (but not anti-citH2A/H2B negative) selectively recognised neutrophil extracellular traps (NETs) from peripheral blood and/or RA joint neutrophils; (3) anti-citH2A/citH2B and anti-NET immunobinding was dependent on affinity maturation and was completely abrogated following reversion of hypermutated IgVH/VL genes to germline sequences; (4) ELS+ (not ELS-) RA synovial tissues engrafted into Severe Combined ImmunoDeficiency (SCID) mice released human anti-citH2A/citH2B and anti-NET antibodies in association with the intra-graft expression of CXCL13 and lymphotoxin (LT)-β, two master regulators of ELS.

CONCLUSION

We provided novel evidence that B cells differentiated within synovial ELS in the RA joints frequent target deiminated proteins which could be generated during NETosis of RA synovial neutrophils including histones. Thus, NETs could represent a source of citrullinated antigens fuelling the ACPA autoimmune response within the RA synovium.

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.

Hand to Mouth: A Systematic Review and Meta-Analysis of the Association between Rheumatoid Arthritis and Periodontitis

Background

Rheumatoid arthritis (RA) and periodontitis are both chronic inflammatory diseases, which demonstrate similarities in terms of mechanism, histopathology, and demography. An association between these conditions has been demonstrated previously but has been called into question more recently.

Methods

The published databases, such as MEDLINE, EMBASE, and PsycINFO, were searched using search terms related to RA and periodontitis. Articles were selected if they included data on the number of people with RA diagnosed with periodontitis (or periodontal disease parameters) compared to a control comparison group. Review articles, case reports, animal model studies, non-English language, and articles with unavailable abstracts were excluded. Data were extracted, critically appraised using the Downs and Black tool, and a random-effect Mantel–Haenszel meta-analysis was performed.

Results

Twenty-one papers met the eligibility criteria and provided data for the meta-analysis; 17 studies (including a total of 153,492 participants) comparing RA to healthy controls and 4 (including a total of 1378 participants) comparing RA to osteoarthritis (OA). There was a significantly increased risk of periodontitis in people with RA compared to healthy controls (relative risk: 1.13; 95% CI: 1.04, 1.23; p = 0.006; N = 153,277) with a significantly raised mean probing depth, risk of bleeding on probing (BOP), and absolute value of clinical attachment loss in those with RA. When comparing RA and OA, there was no significant difference in the prevalence of periodontitis; however, the risk of BOP was greater in OA than RA.

Conclusion

A significant association between RA and periodontitis is supported by the results of our systematic review and meta-analysis of studies comparing RA to healthy controls. In our meta-analysis, however, this is not replicated when comparing RA to OA controls.