Potential role of bacterial infection in autoimmune diseases: a new aspect of molecular mimicry

Do vaccines cause epilepsy? Review of cases in the National Vaccine Injury Compensation Program

OBJECTIVE

The National Childhood Vaccine Injury Act of 1986 created the National Vaccine Injury Compensation Program (VICP), a no-fault alternative to the traditional tort system. Since 1988, the total compensation paid exceeds $5 billion. Although epilepsy is one of the leading reasons for filing a claim, there has been no review of the process and validity of the legal outcomes given current medical information. The objectives were to review the evolution of the VICP program in regard to vaccine-related epilepsy and assess the rationale behind decisions made by the court.

METHODS

Publicly available cases involving epilepsy claims in the VICP were searched through Westlaw and the US Court of Federal Claims websites. All published reports were reviewed for petitioner's theories supporting vaccine-induced epilepsy, respondent's counterarguments, the final decision regarding compensation, and the rationale underlying these decisions. The primary goal was to determine which factors went into decisions regarding whether vaccines caused epilepsy.

RESULTS

Since the first epilepsy case in 1989, there have been many changes in the program, including the removal of residual seizure disorder as a vaccine-related injury, publication of the Althen prongs, release of the acellular form of pertussis, and recognition that in genetic conditions the underlying genetic abnormality rather than the immunization causes epilepsy. We identified 532 unique cases with epilepsy: 105 with infantile spasms and 427 with epilepsy without infantile spasms. The petitioners' experts often espoused outdated, erroneous causation theories that lacked an acceptable medical or scientific foundation and were frequently criticized by the court.

SIGNIFICANCE

Despite the lack of epidemiological or mechanistic evidence indicating that childhood vaccines covered by the VICP result in or aggravate epilepsy, these cases continue to be adjudicated. After 35 years of intense litigation, it is time to reconsider whether epilepsy should continue to be a compensable vaccine-induced injury.

Lung microbiome: new insights into the pathogenesis of respiratory diseases

The lungs were long thought to be sterile until technical advances uncovered the presence of the lung microbial community. The microbiome of healthy lungs is mainly derived from the upper respiratory tract (URT) microbiome but also has its own characteristic flora. The selection mechanisms in the lung, including clearance by coughing, pulmonary macrophages, the oscillation of respiratory cilia, and bacterial inhibition by alveolar surfactant, keep the microbiome transient and mobile, which is different from the microbiome in other organs. The pulmonary bacteriome has been intensively studied recently, but relatively little research has focused on the mycobiome and virome. This up-to-date review retrospectively summarizes the lung microbiome's history, composition, and function. We focus on the interaction of the lung microbiome with the oropharynx and gut microbiome and emphasize the role it plays in the innate and adaptive immune responses. More importantly, we focus on multiple respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD), fibrosis, bronchiectasis, and pneumonia. The impact of the lung microbiome on coronavirus disease 2019 (COVID-19) and lung cancer has also been comprehensively studied. Furthermore, by summarizing the therapeutic potential of the lung microbiome in lung diseases and examining the shortcomings of the field, we propose an outlook of the direction of lung microbiome research.

The Differences in Clinical Manifestations and Prognosis of Infective Endocarditis Patients With Positive Serology to Antineutrophilic Cytoplasmic Antibody Compared to Negative Serology

Previous studies have established a relationship between bacterial proteins and autoimmune diseases through several mechanisms. Infective endocarditis is known for its immunological phenomena, and the presence of antineutrophil cytoplasmic antibodies (ANCA) antibodies has been previously demonstrated in several infectious diseases. This retrospective, comparative, and descriptive study examined the relationship between infective endocarditis and the presence of ANCA antibodies. Ninety infective endocarditis cases were included in the study and tested for ANCA antibodies. The prevalence of ANCA positivity was determined, along with the differences in characteristics and prognosis between infective endocarditis patients with positive and negative serology for ANCA antibodies. The results showed that the characteristics of endocarditis patients who underwent ANCA serology testing were similar to those who did not, except for a higher prevalence of central line and chronic kidney disease in patients with ANCA serology (6.7% compared to 1.1% and 25.6% compared to 12.9%, respectively). Of the 90 endocarditis patients tested for ANCA serology, 18% were ANCA-positive, consistent with other prospective studies. There were no statistically significant differences in the primary outcome, six-month and one-year mortality, between patients with positive and negative ANCA serology. Similarly, in the secondary outcomes of acute kidney injury, heart surgery, and days of hospitalization, there were no statistically significant differences between patients with positive and negative ANCA serology. However, there were statistically significant differences in certain characteristics between the two groups. Patients with positive ANCA serology were found to have a higher prevalence of Enterococcus involvement (29.4% compared to 9.6% with P-value 0.046) and Q fever (23.5% compared to 4.1% P-value 0.02%). In contrast, patients with negative ANCA serology had a higher prevalence of fever (73% compared to 41% P-value 0.033).

Undervalued and novel roles of heterogeneous nuclear ribonucleoproteins in autoimmune diseases: Resurgence as potential biomarkers and targets

Autoimmune diseases are mainly characterized by the abnormal autoreactivity due to the loss of tolerance to specific autoantigens, though multiple pathways associated with the homeostasis of immune responses are involved in initiating or aggravating the conditions. The heterogeneous nuclear ribonucleoproteins (hnRNPs) are a major category of RNA-binding proteins ubiquitously expressed in a multitude of cells and have attracted great attentions especially with their distinctive roles in nucleic acid metabolisms and the pathogenesis in diseases like neurodegenerative disorders and cancers. Nevertheless, the interplay between hnRNPs and autoimmune disorders has not been fully elucidated. Virtually various family members of hnRNPs are increasingly identified as immune players and are pertinent to all kinds of immune-related processes including immune system development and innate or adaptive immune responses. Specifically, hnRNPs have been extensively recognized as autoantigens within and even beyond a myriad of autoimmune diseases, yet their diagnostic and prognostic values are seemingly underestimated. Molecular mimicry, epitope spreading and bystander activation may represent major putative mechanisms underlying the presence of autoantibodies to hnRNPs. Besides, hnRNPs play critical parts in regulating linchpin genes expressions that control genetic susceptibility, disease-linked functional pathways, or immune responses by interacting with other components particularly like microRNAs and long non-coding RNAs, thereby contributing to inflammation and autoimmunity as well as specific disease phenotypes. Therefore, comprehensive unraveling of the roles of hnRNPs is conducive to establishing potential biomarkers and developing better intervention strategies by targeting these hnRNPs in the corresponding disorders. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

Requirements for anti-aquaporin 5 autoantibody production in a mouse model

Several oral bacteria, including Prevotella melaninogenica (Pm), have aquaporin (AQP) proteins homologous to human AQP5, a major water channel protein targeted in Sjogren's syndrome. This study aimed to understand the antigenic characteristics that induce autoantibodies against an AQP5 "E" epitope (AQP5E) in a mouse model using C57BL/6 mice. Immunization with a PmE-L peptide derived from Pm AQP, which contains amino acid mismatches both at the B- and T-cell epitopes, efficiently induced anti-AQP5E autoantibodies accompanied by increased germinal center (GC) B and follicular helper T cells in the draining lymph nodes. However, PmE, a peptide lacking a T-cell epitope, and AQP5E-L, an AQP5-derived self-peptide, hardly induced either anti-AQP5E autoantibodies or GC responses. Surprisingly, OTII-AQP5E, a peptide that replaced the self T-cell epitope of AQP5E-L with an ovalbumin-derived foreign T-cell epitope, was not any better than AQP5E-L in the induction of anti-AQP5E autoantibodies and GC response, despite the substantial expansion of CD4+ T cells and production of anti-OTII-AQP5E antibodies. The complex of biotinylated PmE-L peptide and highly immunogenic streptavidin (SA) induced a strong extrafollicular B-cell response skewed toward the expansion of SA-specific B cells. However, the expansion of AQP5E-specific GC B cells was limited, resulting in the inefficient induction of anti-AQP5E autoantibodies. Collectively, our results have demonstrated that anti-AQP5E autoantibody production is only allowed when foreign B- and T-cell epitopes drive a strong GC response of AQP5E-specific B cells for affinity maturation. This study helps explain why cross-reactive anti-AQP5 autoantibodies are not produced during the immune response to Pm in most healthy people.

Mining Autoimmune-Disorder-Linked Molecular-Mimicry Candidates in Clostridioides difficile and Prospects of Mimic-Based Vaccine Design: An In Silico Approach

Molecular mimicry, a phenomenon in which microbial or environmental antigens resemble host antigens, has been proposed as a potential trigger for autoimmune responses. In this study, we employed a bioinformatics approach to investigate the role of molecular mimicry in Clostridioides difficile-caused infections and the induction of autoimmune disorders due to this phenomenon. Comparing proteomes of host and pathogen, we identified 23 proteins that exhibited significant sequence homology and were linked to autoimmune disorders. The disorders included rheumatoid arthritis, psoriasis, Alzheimer's disease, etc., while infections included viral and bacterial infections like HIV, HCV, and tuberculosis. The structure of the homologous proteins was superposed, and RMSD was calculated to find the maximum deviation, while accounting for rigid and flexible regions. Two sequence mimics (antigenic, non-allergenic, and immunogenic) of ≥10 amino acids from these proteins were used to design a vaccine construct to explore the possibility of eliciting an immune response. Docking analysis of the top vaccine construct C2 showed favorable interactions with HLA and TLR-4 receptor, indicating potential efficacy. The B-cell and T-helper cell activity was also simulated, showing promising results for effective immunization against C. difficile infections. This study highlights the potential of C. difficile to trigger autoimmunity through molecular mimicry and vaccine design based on sequence mimics that trigger a defensive response.

The role of bacterial infections in rheumatoid arthritis development and novel therapeutic interventions: Focus on oral infections

BACKGROUND

Rheumatoid arthritis (RA) represents a primary public health challenge, which is a major source of pain, disability, and socioeconomic effects worldwide. Several factors contribute to its pathogenesis. Infections are an important concern in RA patients, which play a key role in mortality risk. Despite major advances in the clinical treatment of RA, long-term use of disease-modifying anti-rheumatic drugs can cause serious adverse effects. Therefore, effective strategies for developing novel prevention and RA-modifying therapeutic interventions are sorely needed.

OBJECTIVE

This review investigates the available evidence on the interplay between various bacterial infections, particularly oral infections and RA, and focuses on some potential interventions such as probiotics, photodynamic therapy, nanotechnology, and siRNA that can have therapeutic effects.

Plasma Proteomic Profile of Patients with Tick-Borne Encephalitis and Co-Infections

Despite the increasing number of patients suffering from tick-borne encephalitis (TBE), Lyme disease, and their co-infection, the mechanisms of the development of these diseases and their effects on the human body are still unknown. Therefore, the aim of this study was to evaluate the changes in the proteomic profile of human plasma induced by the development of TBE and to compare it with changes in TBE patients co-infected with other tick-borne pathogens. The results obtained by proteomic analysis using a nanoLC-Q Exactive HF mass spectrometer showed that the most highly elevated groups of proteins in the plasma of TBE patients with co-infection were involved in the pro-inflammatory response and protein degradation, while the antioxidant proteins and factors responsible for protein biosynthesis were mainly downregulated. These results were accompanied by enhanced GSH- and 4-HNE-protein adducts formation, observed in TBE and co-infected patients at a higher level than in the case of patients with only TBE. In conclusion, the differences in the proteomic profiles between patients with TBE and co-infected patients indicate that these diseases are significantly diverse and, consequently, require different treatment, which is particularly important for further research, including the development of novel diagnostics tools.

Mechanical model of steady-state and inflammatory conditions in patients with relapsing polychondritis: A review

Relapsing polychondritis (RP) is a multisystem inflammatory disorder, considered to associate with immune aberration.Increased T helper type-1 cell-related cytokines were reported in RP patients. mRNA expressions of a regulatory T cell cytokine interleukin (IL)-10 increased, whereas pro-inflammatory cytokines IL1β and IL6 mRNA expressions decreased in freshly isolated peripheral blood mononuclear cells of RP patients compared with those in healthy individuals. Upon in vitro stimulation with mitogen, IL10 mRNA expressions decreased, and IL1β and IL6 mRNA expressions increased in RP patients.This short-time dynamic change of gene expressions from anti-inflammatory to pro-inflammatory features of immune cells may be associated with the "relapsing" disease course of patients with RP. IL1β mRNA expressions of peripheral blood mononuclear cells exhibited positive correlations with serum matrix metalloproteinase (MMP)-3 concentrations in patients with respiratory involvement. Such positive correlation was not found in those without respiratory involvement.In a metagenomic analysis, an altered composition of gut microbes was found, suggesting that microbe metabolites such as short-chain fatty acids may affect T cell responses of the patients.In this review, the relationships among RP-related inflammatory molecules were summarized. The data support a hypothesis that the immune conditions are different between steady-state and inflammation in RP patients.

Why Should We Consider Potential Roles of Oral Bacteria in the Pathogenesis of Sjögren Syndrome?

Sjögren syndrome (SS) is a chronic autoimmune disorder that primarily targets the salivary and lacrimal glands. The pathology of these exocrine glands is characterized by periductal focal lymphocytic infiltrates, and both T cell-mediated tissue injury and autoantibodies that interfere with the secretion process underlie glandular hypofunction. In addition to these adaptive mechanisms, multiple innate immune pathways are dysregulated, particularly in the salivary gland epithelium. Our understanding of the pathogenetic mechanisms of SS has substantially improved during the past decade. In contrast to viral infection, bacterial infection has never been considered in the pathogenesis of SS. In this review, oral dysbiosis associated with SS and evidence for bacterial infection of the salivary glands in SS were reviewed. In addition, the potential contributions of bacterial infection to innate activation of ductal epithelial cells, plasmacytoid dendritic cells, and B cells and to the breach of tolerance via bystander activation of autoreactive T cells and molecular mimicry were discussed. The added roles of bacteria may extend our understanding of the pathogenetic mechanisms and therapeutic approaches for this autoimmune exocrinopathy.

Induction of Anti-Aquaporin 5 Autoantibody Production by Immunization with a Peptide Derived from the Aquaporin of Prevotella melaninogenica Leads to Reduced Salivary Flow in Mice

Sjögren's syndrome (SS) is an autoimmune disease characterized by dryness of the mouth and eyes. The glandular dysfunction in SS involves not only T cell-mediated destruction of the glands but also autoantibodies against the type 3 muscarinic acetylcholine receptor or aquaporin 5 (AQP5) that interfere with the secretion process. Studies on the breakage of tolerance and induction of autoantibodies to these autoantigens could benefit SS patients. To break tolerance, we utilized a PmE-L peptide derived from the AQP5-homologous aquaporin of Prevotella melaninogenica (PmAqp) that contained both a B cell "E" epitope and a T cell epitope. Repeated subcutaneous immunization of C57BL/6 mice with the PmE-L peptide efficiently induced the production of Abs against the "E" epitope of mouse/human AQP5 (AQP5E), and we aimed to characterize the antigen specificity, the sequences of AQP5E-specific B cell receptors, and salivary gland phenotypes of these mice. Sera containing anti-AQP5E IgG not only stained mouse Aqp5 expressed in the submandibular glands but also detected PmApq and PmE-L by immunoblotting, suggesting molecular mimicry. Characterization of the AQP5E-specific autoantibodies selected from the screening of phage display Ab libraries and mapping of the B cell receptor repertoires revealed that the AQP5E-specific B cells acquired the ability to bind to the Ag through cumulative somatic hypermutation. Importantly, animals with anti-AQP5E Abs had decreased salivary flow rates without immune cell infiltration into the salivary glands. This model will be useful for investigating the role of anti-AQP5 autoantibodies in glandular dysfunction in SS and testing new therapeutics targeting autoantibody production.

Diagnostic and Predictive Contribution of Autoantibodies Screening in a Large Series of Patients With Primary Immunodeficiencies

Objectives

To evaluate the diagnostic and predictive contribution of autoantibodies screening in patients with primary immunodeficiencies (PIDs).

Methods

In the present study, PID patients and healthy controls have been screened for 54 different autoantibodies. The results of autoantibodies screening in PID patients were correlated to the presence of autoimmune diseases.

Results

A total of 299 PID patients were included in this study with a predominance of antibody deficiencies (27.8%) followed by immunodeficiencies affecting cellular and humoral immunity (26.1%) and complement deficiencies (22.7%). Autoimmune manifestations were present in 82 (27.4%) patients. Autoimmune cytopenia (10.4%) was the most common autoimmune disease followed by gastrointestinal disorders (10.0%), rheumatologic diseases (3.7%), and endocrine disorders (3.3%). Autoantibodies were found in 32.4% of PID patients and 15.8% of healthy controls (P < 0.0005). Anti-nuclear antibodies (ANA) (10.0%), transglutaminase antibody (TGA) (8.4%), RBC antibodies (6.7%), anti-smooth muscle antibody (ASMA) (5.4%), and ASCA (5.0%) were the most common autoantibodies in our series. Sixty-seven out of the 82 patients with autoimmune manifestations (81.7%) were positive for one or more autoantibodies. Eleven out of the 14 patients (78.6%) with immune thrombocytopenia had positive platelet-bound IgM. The frequencies of ASCA and ANCA among patients with IBD were 47.4% and 21.0% respectively. All patients with celiac disease had TGA-IgA, while six out of the 11 patients with rheumatologic diseases had ANA (54.5%). Almost one third of patients (30/97) with positive autoantibodies had no autoimmune manifestations. ANA, rheumatoid factor, ASMA, anti-phospholipid antibodies and ANCA were often detected while specific AID was absent. Despite the low positive predictive value of TGA-IgA and ASCA for celiac disease and inflammatory bowel disease respectively, screening for these antibodies identified undiagnosed disease in four patients with positive TGA-IgA and two others with positive ASCA.

Conclusion

The present study provides valuable information about the frequency and the diagnostic/predictive value of a large panel of autoantibodies in PIDs. Given the frequent association of some AIDs with certain PIDs, screening for corresponding autoantibodies would be recommended. However, positivity for autoantibodies should be interpreted with caution in patients with PIDs due to their low positive predictive value.

Genomic characterization of four Escherichia coli strains isolated from oral lichen planus biopsies

Oral lichen planus (OLP) is a chronic T cell-mediated inflammatory disease that affects the mucus membrane of the oral cavity. We previously proposed a potential role of intracellular bacteria detected within OLP lesions in the pathogenesis of OLP and isolated four Escherichia coli strains from OLP tissues that were phylogenetically close to K-12 MG1655 strain. We sequenced the genomes of the four OLP-isolated E. coli strains and generated 6.71 Gbp of Illumina MiSeq data (166–195x coverage per strain). The size of the assembled draft genomes was 4.69 Mbp, with a GC content of 50.7%, in which 4360 to 4367 protein-coding sequences per strain were annotated. We also identified 368 virulence factors and 53 antibiotic resistance genes. Comparative genomics revealed that the OLP-isolated strains shared more pangenome orthologous groups with pathogenic strains than did the K-12 MG1655 strain, a derivative of K-12 strain isolated from human feces. Although the OLP-isolated strains did not have the major virulence factors (VFs) of the pathogenic strains, a number of VFs involved in adherence/invasion, colonization, or systemic infection were identified. The genomic characteristics of E. coli first isolated from the oral cavity would benefit future investigations on the pathogenic potential of these bacteria.

Method for Specific Identification of the Emerging Zoonotic Pathogen Vibrio vulnificus Lineage 3 (Formerly Biotype 3)

Vibrio vulnificus is a zoonotic pathogen that is spreading worldwide due to global warming. Lineage 3 (L3; formerly biotype 3) includes the strains of the species with the unique ability to cause fish farm-linked outbreaks of septicemia. The L3 strains emerged recently and are particularly virulent and difficult to identify. Here, we describe a newly developed PCR method based on a comparative genomic study useful for both rapid identification and epidemiological studies of this interesting emerging group. The comparative genomic analysis also revealed the presence of a genetic duplication in the L3 strains that could be related to the unique ability of this lineage to produce septicemia outbreaks.

Examining pathogenic concepts of autoimmune hepatitis for cues to future investigations and interventions

BACKGROUND

Multiple pathogenic mechanisms have been implicated in autoimmune hepatitis, but they have not fully explained susceptibility, triggering events, and maintenance or escalation of the disease. Furthermore, they have not identified a critical defect that can be targeted. The goals of this review are to examine the diverse pathogenic mechanisms that have been considered in autoimmune hepatitis, indicate investigational opportunities to validate their contribution, and suggest interventions that might evolve to modify their impact. English abstracts were identified in PubMed by multiple search terms. Full length articles were selected for review, and secondary and tertiary bibliographies were developed. Genetic and epigenetic factors can affect susceptibility by influencing the expression of immune regulatory genes. Thymic dysfunction, possibly related to deficient production of programmed cell death protein-1, can allow autoreactive T cells to escape deletion, and alterations in the intestinal microbiome may help overcome immune tolerance and affect gender bias. Environmental factors may trigger the disease or induce epigenetic changes in gene function. Molecular mimicry, epitope spread, bystander activation, neo-antigen production, lymphocytic polyspecificity, and disturbances in immune inhibitory mechanisms may maintain or escalate the disease. Interventions that modify epigenetic effects on gene expression, alter intestinal dysbiosis, eliminate deleterious environmental factors, and target critical pathogenic mechanisms are therapeutic possibilities that might reduce risk, individualize management, and improve outcome. In conclusion, diverse pathogenic mechanisms have been implicated in autoimmune hepatitis, and they may identify a critical factor or sequence that can be validated and used to direct future management and preventive strategies.

Autoimmune manifestations of infections

PURPOSE OF REVIEW

To provide an update about the interactions between infections and autoimmune diseases (AIDs), from the molecular perspective to the clinical spectrum and the differentiation between infection and disease activity.

RECENT FINDINGS

Any kind of infection may modify the innate and adaptive immune response through the following mechanisms: molecular mimicry, superantigens, epitope spreading and B-cell activation. The consequence is the overproduction of antibodies shared with those found in AIDs. Viral infections, especially HIV and hepatitis C virus, can stimulate the production of antiphospholipid antibodies and confer an increased risk to develop antiphospholipid syndrome.

SUMMARY

The identification of risk factors to develop infections in patients with AIDs is remarkable to prevent them. These factors are the use of steroids and immunosuppressants, the involvement of a major organ (lungs, brain and kidney) and severe activity. Biomarkers to differentiate infection from disease activity are scarce, but the combination of procalcitonine and C-reactive protein seems to have higher specificity and sensibility to identify infections in patients with AIDs. Finally, the clinical judgment is the hallmark to differentiate between infections and disease activity.

Pathogenesis and treatment of autoimmune rheumatic diseases

PURPOSE OF REVIEW

Autoimmune diseases are of unknown origin, and they represent significant causes of morbidity and mortality. Here, we review new developments in the understanding of their pathogenesis that have led to development of well tolerated and effective treatments.

RECENT FINDINGS

In addition to the long-recognized genetic impact of the HLA locus, interferon regulatory factors, PTPN22, STAT4, and NOX have been implicated in pathogenesis of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Smoking, ultraviolet light, diet, and microbiota exert strong environmental influence on development of RA and SLE. Metabolism has been recognized as a critical integrator of genetic and environmental factors, and it controls immune cell differentiation both under physiological and pathological conditions.

SUMMARY

With the advent of high-throughput genetic, proteomic, and metabolomic technologies, the field of medicine has been shifting towards systems-based and personalized approaches to diagnose and treat common conditions, including rheumatic diseases. Regulatory checkpoints of metabolism and signal transduction, such as glucose utilization, mitochondrial electron transport, JAK, mTOR, and AMPK pathway activation, and production of pro-inflammatory cytokines IL-1, IL-6, and IL-17 have presented new targets for therapeutic intervention. This review amalgamates recent discoveries in genetics and metabolomics with immunological pathways of pathogenesis in rheumatic diseases.

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.

Diagnosis and Management of Rheumatoid Arthritis: A Review

IMPORTANCE

Rheumatoid arthritis (RA) occurs in about 5 per 1000 people and can lead to severe joint damage and disability. Significant progress has been made over the past 2 decades regarding understanding of disease pathophysiology, optimal outcome measures, and effective treatment strategies, including the recognition of the importance of diagnosing and treating RA early.

OBSERVATIONS

Early diagnosis and treatment of RA can avert or substantially slow progression of joint damage in up to 90% of patients, thereby preventing irreversible disability. The development of novel instruments to measure disease activity and identify the presence or absence of remission have facilitated new treatment strategies to arrest RA before joints are damaged irreversibly. Outcomes have been improved by recognizing the benefits of early diagnosis and early therapy with disease-modifying antirheumatic drugs (DMARDs). The treatment target is remission or a state of at least low disease activity, which should be attained within 6 months. Methotrexate is first-line therapy and should be prescribed at an optimal dose of 25 mg weekly and in combination with glucocorticoids; 40% to 50% of patients reach remission or at least low disease activity with this regimen. If this treatment fails, sequential application of targeted therapies, such as biologic agents (eg, tumor necrosis factor [TNF] inhibitors) or Janus kinase inhibitors in combination with methotrexate, have allowed up to 75% of these patients to reach the treatment target over time. New therapies have been developed in response to new pathogenetic findings. The costs of some therapies are considerable, but these costs are decreasing with the advent of biosimilar drugs (drugs essentially identical to the original biologic drugs but usually available at lower cost).

CONCLUSIONS AND RELEVANCE

Scientific advances have improved therapies that prevent progression of irreversible joint damage in up to 90% of patients with RA. Early treatment with methotrexate plus glucocorticoids and subsequently with other DMARDs, such as inhibitors of TNF, IL-6, or Janus kinases, improves outcomes and prevents RA-related disability. A treat-to-target strategy aimed at reducing disease activity by at least 50% within 3 months and achieving remission or low disease activity within 6 months, with sequential drug treatment if needed, can prevent RA-related disability.

The Problem of Curcumin and Its Bioavailability: Could Its Gastrointestinal Influence Contribute to Its Overall Health-Enhancing Effects?

Curcumin, from the spice turmeric, exhibits anti-inflammatory, antioxidant, anticancer, antiviral, and neurotrophic activity and therefore holds promise as a therapeutic agent to prevent and treat several disorders. However, a major barrier to curcumin's clinical efficacy is its poor bioavailability. Efforts have therefore been dedicated to developing curcumin formulations with greater bioavailability and systemic tissue distribution. However, it is proposed in this review that curcumin's potential as a therapeutic agent may not solely rely on its bioavailability, but rather its medicinal benefits may also arise from its positive influence on gastrointestinal health and function. In this review, in vitro, animal, and human studies investigating the effects of curcumin on intestinal microbiota, intestinal permeability, gut inflammation and oxidative stress, anaphylactic response, and bacterial, parasitic, and fungal infections are summarized. It is argued that positive changes in these areas can have wide-ranging influences on both intestinal and extraintestinal diseases, and therefore presents as a possible mechanism behind curcumin's therapeutic efficacy.

Atopobium and Fusobacterium as novel candidates for sarcoidosis-associated microbiota

Sarcoidosis is a granulomatous disease that mainly affects the lung. A role of microbial factors in disease pathogenesis is assumed, but has not been investigated systematically in a large cohort.This cross-sectional study compared the lung microbiota of 71 patients with sarcoidosis, 15 patients with idiopathic pulmonary fibrosis (non-infectious controls) and 10 healthy controls (HCs). Next-generation sequencing of 16S DNA was used on bronchoalveolar lavage samples to characterise the microbial composition, which was analysed for diversity and indicator species. Host genotypes for 13 known sarcoidosis risk variants were determined and correlated with microbial parameters.The microbial composition differed significantly between sarcoidosis and HC samples (redundancy analysis ANOVA, p=0.025) and between radiographic Scadding types. Atopobium spp. was detected in 68% of sarcoidosis samples, but not in HC samples. Fusobacterium spp. was significantly more abundant in sarcoidosis samples compared with those from HCs. Mycobacteria were found in two of 71 sarcoidosis samples. Host-genotype analysis revealed an association of the rs2076530 (BTNL2) risk allele with a decrease in bacterial burden (p=0.002).Our results indicate Scadding type-dependent microbiota in sarcoidosis BAL samples. Atopobium spp. and Fusobacterium spp. were identified as sarcoidosis-associated bacteria, which may enable new insights into the pathogenesis and treatment of the disease.

Blueberry Phenolics Reduce Gastrointestinal Infection of Patients with Cerebral Venous Thrombosis by Improving Depressant-Induced Autoimmune Disorder via miR-155-Mediated Brain-Derived Neurotrophic Factor

Cerebral venous thrombosis (CVT) often causes human depression, whereas depression-induced low immunity makes the patients susceptible to gastrointestinal infection. Blueberry possesses antidepressant properties which may improve autoimmunity and reduce gastrointestinal infection. Brain-derived neurotrophic factor (BDNF) performs antidepressant function and can be regulated by miR-155, which may be affected by blueberry. To explore the possible molecular mechanism, blueberry compounds were analyzed by high-performance liquid chromatography. Activity of compounds was tested by using HT22 cells. The present study tested 124 patients with CVT-induced mild-to-moderate depressive symptoms (Center for Epidemiologic Studies—Depression Scale [CES-D] ≥16) and gastrointestinal infection. Patients were randomly assigned to blueberry extract group (BG, received 10 mg blueberry extract daily) and placebo group (PG, received 10 mg placebo daily). After 3 months, depression, gastrointestinal infection and lipid profiles were investigated. Serum miR-155 and BDNF were measured using real-time quantitative polymerase chain reaction and or Western Blot. Blueberry treatment improved depressive symptoms and lipid profiles, and also reduced gastrointestinal infection in the BG group (P < 0.05) but those of the PG group (P = 1). These changes were paralleled by increase in serum levels of BDNF and miR-155 (P < 0.05). HPLC analysis showed that blueberry extracts were the main phenolic acids with 0.18, 0.85, 0.26, 0.72, 0.66, 0.4,1, and 1.92 mg/g of gentisic acid, chlorogenic acid, [2]-epicatechin, p-coumaric acid, benzoic acid, p-anisic acid, and quercetin in blueberry extracts, respectively. Phenolics in blueberry are possible causal agents in improving antidepressant activity and reducing gastrointestinal infection. Administration of blueberry increased BDNF expression and miR-155. Blueberry cannot affect BDNF level when miR-155 is overexpressed or inhibited. Phenolics from blueberry reduced gastrointestinal infection of patients with CVT by improving antidepressant activity via upregulation of miR-155-mediated BDNF.

Functional Epitopes for Anti-Aquaporin 5 Antibodies in Sjögren Syndrome

We recently reported the presence of anti-aquaporin 5 (AQP5) immunoglobulin G (IgG) in patients with primary Sjögren syndrome (SS) with a sensitivity of 0.73 and a specificity of 0.68. The aim of this study was to identify functional epitopes for the anti-AQP5 autoantibodies detected in control subjects and patients with SS. Recognition of epitopes by anti-AQP5 autoantibodies in sera ( n = 13 for control and n = 24 for SS) or purified IgG ( n = 1 for control and n = 3 for SS) was evaluated by indirect immunofluorescence (IIF) assay performed in the presence or absence of peptides corresponding to the second transmembrane helix and extracellular loops A, C, and E of AQP5. Functional epitopes were determined by measuring the effects of purified IgG and neutralizing peptides on transepithelial osmotic permeability (P_f^T) of MDCK cells expressing AQP5. In the IIF assay, 89% of SS samples were inhibited by at least 1 peptide, while only half of control samples were inhibited by any peptide. Overall, SS samples were inhibited by peptides corresponding to extracellular loops A, C, and E by 40% to 50%, whereas control samples were inhibited only by peptides corresponding to loop E by <20%. A cyclized peptide (E1) mimicking loop E was most frequently recognized and best differentiated between the SS and control samples. Incubation of MDCK-AQP5 cells with SS but not with control IgG, significantly decreased P_f^T, which was reversed by neutralization of IgG binding to any of the extracellular loops. In conclusion, the anti-AQP5 autoantibodies detected in control and SS groups showed differences in fine specificity to the functional epitopes of AQP5. The prevalent recognition of functional epitopes by anti-AQP5 autoantibodies from SS patients suggests that anti-AQP5 autoantibodies act as mediators of glandular hypofunction and are a potential therapeutic target in SS.

Induction of proteinase 3-anti-neutrophil cytoplasmic autoantibodies by proteinase 3-homologous bacterial protease in mice

Proteinase 3 (PR3) is the principal target of antineutrophil cytoplasmic autoantibodies (ANCA) associated with granulomatosis with polyangiitis. The aim of this study was to investigate whether bacterial PR3-homologous protease can induce autoantibodies to PR3 and ANCA-associated pathology in mice. Among the bacterial proteases that have greater than 30 % identity with PR3, a trypsin-like serine protease of Saccharomonospora viridis, a bacterium that causes hypersensitivity pneumonitis, was chosen. When the mice were immunized with the recombinant protease of S. viridis (SvPR), 75 % of NZBWF1 and 100 % of C57BL/6 mice developed high levels of autoantibodies to mouse PR3 (mPR3). The levels of antibodies to mPR3 had a strong positive correlation with those to SvPR. In addition, more than half of the mPR3-reactive sera (63 %) reacted to purified human PR3 (hPR3), and the levels of antibodies to hPR3 had a positive correlation with those to mPR3. The sera from the immunized mice strongly stained murine neutrophils in a C-ANCA pattern. Although granulomatous inflammation and signs of vasculitis were observed in several mice, they were attributable to the use of complete Freund's adjuvant in the immunization. Collectively, exposure to PR3-homologous bacterial protease could induce ANCA in mice, and this finding may provide a new insight into the triggering mechanisms for the production of PR3-ANCA.

Different forms of alpha-1 antitrypsin and neutrophil activation mediated by human anti-PR3 IgG antibodies

BACKGROUND

One of characteristic findings in granulomatosis with polyangiitis (GPA) is the presence of proteinase-3 (anti-PR3) specific antibodies. These antibodies can cause neutrophil activation, degranulation and generation of reactive oxygen species (ROS). Each of these inflammatory events can be suppressed by circulating alpha-1 antitrypsin (A1AT). A1AT is an acute phase protein increasing during inflammation, however, it may circulate as an inactive polymeric protein. The aim was to analyze how different types of A1AT can affect anti-PR3 mediated neutrophil activation.

METHODS

Granulocytes were obtained from the blood of healthy volunteers and purified by density gradient centrifugation. Effects of A1AT on IgG anti-PR3-mediated neutrophil activation were evaluated by stimulation of the cells with native IgG anti-PR3 antibodies in the presence of native or polymerized A1AT. Analyses of selected proinflammatory genes expression were performed using quantitative real-time. Flow cytometry was used to study the cell membrane PR3, its binding by anti-PR3 IgG, and production of ROS at presence A1AT. Neutrophil elastase complexes with A1AT were measured by ELISA.

RESULTS

Native A1AT inhibited formation of the immune complex of PR3 with anti-PR3 and anti-PR3-mediated neutrophil activation/ROS production. Protective effect of polymerized A1AT against these events was diminished at least fivefold.

CONCLUSIONS

Native A1AT can prevent pivotal events of neutrophils' activation by anti-PR3 IgG, the main autoantibody in anti-PR3 dependent vasculitis. Inhibitory properties of polymerized A1AT, decreased plausibly due to a loss of anti-protease function, can explain more severe course of the disease in subjects with deficiency of A1AT.

Identification and molecular docking analysis of active ingredients with medicinal properties from edible Baccaurea sapida

Underutilized plant species has started changing the conception of plants by expanding the use well beyond from foods and fibers to rich source of medicinally important secondary metabolites. Bioactive compounds from natural sources are gaining importance as potential drug candidates towards many inflammatory conditions like Rheumatoid Arthritis (RA). The focus of the present study has been centred to reveal the anti-inflammatory potential of an underutilized fruits of B. sapida. Further efforts towards its medicinal significance may provide relieve from symptoms of RA by reducing the side effects that are observed in available medications. Total 10 compounds in fruit crude methanol extract were identified and quantified by LC-MS/MS analysis followed by the agar well diffusion method for their anti microbial activity. Among all studied micro organism S. aureus was found to surmount the inflammation in RA through domain B of surface protein A (Staphylococcal surface protein A). Identified compounds (having anti-inflammatory properties) were scrutinized for their toxicity and quantitative structure-activity relationship (QSAR) using lazer toxicity and Molinspiration servers respectively. Further, docking studies have been carried out between domain B and studied compounds using AutoDock. Out of 6 anti-inflammtory compounds, quercetin has been identified as the most potent compound in reference to its inhibitory constant (47.01) and binding energy (-5.90 kcal/mol) to bacterial protein. Our data suggest that methanol extract of B. sapida fruit posses medicinally significant anti-inflammatory compounds and thus justifies the use of this fruit as folklore medicine for preventing inflammation related diseases.

Dichotomous roles for externalized cardiolipin in extracellular signaling: Promotion of phagocytosis and attenuation of innate immunity

Among the distinct molecular signatures present in the mitochondrion is the tetra-acylated anionic phospholipid cardiolipin, a lipid also present in primordial, single-cell bacterial ancestors of mitochondria and multiple bacterial species today. Cardiolipin is normally localized to the inner mitochondrial membrane; however, when cardiolipin becomes externalized to the surface of dysregulated mitochondria, it promotes inflammasome activation and stimulates the elimination of damaged or nonfunctional mitochondria by mitophagy. Given the immunogenicity of mitochondrial and bacterial membranes that are released during sterile and pathogen-induced trauma, we hypothesized that cardiolipins might function as "eat me" signals for professional phagocytes. In experiments with macrophage cell lines and primary macrophages, we found that membranes with mitochondrial or bacterial cardiolipins on their surface were engulfed through phagocytosis, which depended on the scavenger receptor CD36. Distinct from this process, the copresentation of cardiolipin with the Toll-like receptor 4 (TLR4) agonist lipopolysaccharide dampened TLR4-stimulated production of cytokines. These data suggest that externalized, extracellular cardiolipins play a dual role in host-host and host-pathogen interactions by promoting phagocytosis and attenuating inflammatory immune responses.

Pathophysiological Relationship between Infections and Systemic Vasculitis

The development of autoimmune disorders requires a combination of genetic, immunological, and environmental factors. Infectious agents, such as viruses and bacteria, can trigger autoimmunity through different mechanisms, and for systemic vasculitis in particular, microbial agents have been suggested to be involved in its pathogenesis. Although the exact mechanisms have not been fully elucidated, different theories have been postulated. This review considers the role of infections in the etiology of primary vasculitis, emphasizing their related immunological events.