Tolerance In Rheumatoid Arthritis Research Articles

A DNA origami device spatially controls CD95 signalling to induce immune tolerance in rheumatoid arthritis.

DNA origami is capable of spatially organizing molecules into sophisticated geometric patterns with nanometric precision. Here we describe a reconfigurable, two-dimensional DNA origami with geometrically patterned CD95 ligands that regulates immune cell signalling to alleviate rheumatoid arthritis. In response to pH changes, the device reversibly transforms from a closed to an open configuration, displaying a hexagonal pattern of CD95 ligands with ~10 nm intermolecular spacing, precisely mirroring the spatial arrangement of CD95 receptor clusters on the surface of immune cells. In a collagen-induced arthritis mouse model, DNA origami elicits robust and selective activation of CD95 death-inducing signalling in activated immune cells located in inflamed synovial tissues. Such localized immune tolerance ameliorates joint damage with no noticeable side effects. This device allows for the precise spatial control of cellular signalling, expanding our understanding of ligand-receptor interactions and is a promising platform for the development of pharmacological interventions targeting these interactions.

Comprehensive insights into rheumatoid arthritis: Pathophysiology, current therapies and herbal alternatives for effective disease management.

Rheumatoid arthritis is a chronic autoimmune inflammatory disease characterized by immune response overexpression, causing pain and swelling in the synovial joints. This condition is caused by auto-reactive antibodies that attack self-antigens due to their incapacity to distinguish between self and foreign molecules. Dysregulated activity within numerous signalling and immunological pathways supports the disease's development and progression, elevating its complexity. While current treatments provide some alleviation, their effectiveness is accompanied by a variety of adverse effects that are inherent in conventional medications. As a result, there is a deep-rooted necessity to investigate alternate therapeutic strategies capable of neutralizing these disadvantages. Medicinal herbs display a variety of potent bioactive phytochemicals that are effective in the complementary management of disease, thus generating an enormous potency for the researchers to delve deep into the development of novel phytomedicine against autoimmune diseases, although additional evidence and understanding are required in terms of their efficacy and pharmacodynamic mechanisms. This literature-based review highlights the dysregulation of immune tolerance in rheumatoid arthritis, analyses the pathophysiology, elucidates relevant signalling pathways involved, evaluates present and future therapy options and underscores the therapeutic attributes of a diverse array of medicinal herbs in addressing this severe disease.

Citrullination modulates antigen processing and presentation by revealing cryptic epitopes in rheumatoid arthritis

Cryptic peptides, hidden from the immune system under physiologic conditions, are revealed by changes to MHC class II processing and hypothesized to drive the loss of immune tolerance to self-antigens in autoimmunity. Rheumatoid arthritis (RA) is an autoimmune disease characterized by immune responses to citrullinated self-antigens, in which arginine residues are converted to citrullines. Here, we investigate the hypothesis that citrullination exposes cryptic peptides by modifying protein structure and proteolytic cleavage. We show that citrullination alters processing and presentation of autoantigens, resulting in the generation of a unique citrullination-dependent repertoire composed primarily of native sequences. This repertoire stimulates T cells from RA patients with anti-citrullinated protein antibodies more robustly than controls. The generation of this unique repertoire is achieved through altered protease cleavage and protein destabilization, rather than direct presentation of citrulline-containing epitopes, suggesting a novel paradigm for the role of protein citrullination in the breach of immune tolerance in RA.

C-terminal citrullinated peptide alters antigen-specific APC:T cell interactions leading to breach of immune tolerance

In rheumatoid arthritis, the emergence of anti-citrullinated autoimmunity is associated with HLA-antigen-T cell receptor complexes. The precise mechanisms underpinning this breach of tolerance are not well understood. Porphyromonas gingivalis expresses an enzyme capable of non-endogenous C-terminal citrullination with potential to generate citrullinated autoantigens. Here we document how C-terminal citrullination of ovalbumin peptide323-339 alters the interaction between antigen-presenting cells and OTII T cells to induce functional changes in responding T cells. These data reveal that C-terminal citrullination is sufficient to breach T cell peripheral tolerance in vivo and reveal the potential of C-terminal citrullination to lower the threshold for T cell activation. Finally, we demonstrate a role for the IL-2/STAT5/CD25 signalling axis in breach of tolerance. Together, our data identify a tractable mechanism and targetable pathways underpinning breach of tolerance in rheumatoid arthritis and provide new conceptual insight into the origins of anti-citrullinated autoimmunity.

COVID-19 vaccination in autoimmune diseases (COVAD) study: vaccine safety and tolerance in rheumatoid arthritis.

The COVID-19 vaccination in autoimmune diseases (COVAD) study aimed to assess short-term COVID-19 vaccination-related adverse events (AEs) in RA patients. An online self-reported questionnaire (March-December 2021) was used to capture data related to COVID-19 vaccination-related AEs in RA, other autoimmune rheumatic diseases (AIRDs) (excluding RA and inflammatory myositis), non-rheumatic autoimmune diseases (nrAIDs) and healthy controls (HCs). Descriptive and multivariable regression analyses were performed. Of the 9462 complete respondents, 14.2% (n = 1347) had been diagnosed with RA; they had a mean (s.d.) age of 50.7 (13.7) years, 74.2% were women and 49.3% were Caucasian. In total, 76.9% and 4.2% of patients with RA reported minor and major AEs, respectively. Patients with active and inactive RA had similar AE and hospitalization frequencies. Overall, AEs were reported more frequently by BNT162b2 and mRNA-1273 recipients and less frequently by BBV152 recipients compared with the rest. Major AE and hospitalization frequencies were similar across recipients of different vaccines. Patients receiving methotrexate and hydroxychloroquine reported fewer minor AEs than those patients not on them. Compared with HCs and patients with other AIRDs, patients with RA reported similar total AEs, overall minor AEs, and hospitalizations. Compared with nrAIDs, patients with RA reported lower frequencies of overall AEs, minor AEs (both odds ratio [OR] = 0.7; 95% CI: 0.5, 0.9), and injection site pain (OR = 0.6; 95% CI: 0.5, 0.8) with similar major AE and hospitalization frequencies. Despite the differences in AE frequency across different COVID-19 vaccines, all were well tolerated in patients with RA and were comparable to HCs, providing reassurance as to the safety of COVID-19 vaccination.

Citrullination modulates MHC class II antigen processing and presentation by revealing cryptic epitopes

Abstract Cryptic peptides, hidden from the immune system under physiologic conditions, are revealed by changes to MHC class II processing and can facilitate loss of tolerance to self-antigens. Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by immune responses to citrullinated self-antigens, in which arginine residues are converted to citrullines; however, the initiating events in RA remain poorly understood. We investigated the hypothesis that citrullination exposes cryptic epitopes by modifying protein structure and proteolysis in a manner sufficient to activate a previously ignorant repertoire of self-reactive T cells. We first utilized in vitro proteolytic mapping to define the effect of citrullination on four well-defined RA autoantigens-. We then used a natural antigen processing assay to elucidate the molecular mechanisms of citrullination-modulated processing and evaluated autoantigen-specific T cell responses against the unique peptide repertoire. We show that citrullination alters MHC class II processing and presentation of RA autoantigens, resulting in the destruction of dominant epitopes and the generation and presentation of cryptic epitopes, composed primarily of native peptide sequences. The citrullination-dependent repertoire stimulates T cells from RA patients with anti-citrullinated protein antibodies more robustly than the native repertoire and control T cells. The generation of this unique repertoire is achieved through altered protease affinity and protein destabilization, rather than direct presentation of citrulline-containing epitopes, suggesting a novel paradigm for the role of protein citrullination in the breach of immune tolerance in RA. Supported by a grant from the Rheumatology Research Foundation and by the Luke Evnin and Deann Wright Fellowship

Restoring immunological tolerance in established experimental arthritis by combinatorial citrullinated peptides and immunomodulatory signals

Promoted tolerance is a coveted therapeutic approach for rheumatoid arthritis (RA), as current immunosuppressive treatments are not disease-specific, primarily targeting the inflammatory response and exerting debilitating side effects. The cellular and antigenic complexity of RA challenges the design of nanoparticle-based tolerogenic strategies to selectively and comprehensively ameliorate joint destruction and restore immune tolerance in RA. Herein, we aimed at exploring the therapeutic effects and tolerogenic mechanism of a novel “tolerogenic polypeptide vaccine” (TPvax), which carried a multiepitope citrullinated peptide (Cit-ME) and rapamycin (Rapa), in established experimental arthritis. A low dose Rapa helped to drive the generation of anti-inflammatory cytokines and tolerogenic dendritic cells (DCs), thereby providing an immunosuppressive microenvironment for tolerance induction. We demonstrated that TPvax enabled the synergism between Cit-ME and Rapa, which led to the upregulation of regulatory T cells (Treg), promotion of IL-10 secretion and reduction of pro-inflammatory cytokines and antibody titers. Importantly, we provided evidence of epitope spreading to citrullinated antigens in collagen-induced arthritis (CIA) and demonstrated that co-delivery of Cit-ME and Rapa promoted immune tolerance even during an ongoing inflammatory event. This work would shed light to the development of tolerogenic therapeutics as novel immunotherapies for RA.

Nanoemulsions Target to Ectopic Lymphoids in Inflamed Joints to Restore Immune Tolerance in Rheumatoid Arthritis.

Inducing immune tolerance through repeated administration of self-antigens is a promising strategy for treating rheumatoid arthritis (RA), and current research indicates that coadministration of immunomodulators can further orchestrate the tolerogenic response. However, most of the clinical trials based on tolerance induction have negligible therapeutic effects. Peripheral lymphoid organs play critical roles in immunotherapy. Here, we design an engineered nanoemulsion for targeted codelivery of self-antigens and an immunomodulator to ectopic lymphoid structures (ELSs) in inflamed joints of RA. Namely, a citrullinated multiepitope self-antigen (CitP) and rapamycin are incorporated into the nanoemulsions (NEs@CitP/Rapa), which are fabricated by a facial method using commercialized pharmaceutical excipients. After intravenous administration, the nanoemulsion shows satisfactory accumulation in the inflamed paws and provides enhanced anti-inflammatory effect in various experimental murine models of RA. Our study provides a promising targeting strategy to induce immune tolerance for the treatment of RA.

Autoantigens in rheumatoid arthritis and the potential for antigen-specific tolerising immunotherapy.

Autoimmune diseases, including rheumatoid arthritis, develop and persist due to impaired immune self-tolerance, which has evolved to regulate inflammatory responses to injury or infection. After diagnosis, patients rarely achieve drug-free remission, and although at-risk individuals can be identified with genotyping, antibody tests, and symptoms, rheumatoid arthritis cannot yet be successfully prevented. Precision medicine is increasingly offering solutions to diseases that were previously considered to be incurable, and immunotherapy has begun to achieve this aim in cancer. Comparatively, modulating autoantigen-specific immune responses with immunotherapy for the cure of autoimmune diseases is at a relatively immature stage. Current treatments using non-specific immune or inflammatory suppression increase susceptibility to infection, and are rarely curative. However, early stage clinical trials suggesting that immunotherapy might allow extended duration of remission and even prevention of progression to disease suggest modulating tolerance in rheumatoid arthritis could be a promising opportunity for therapy.

Low-dose Interleukin-2: Biology and therapeutic prospects in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic aggressive arthritis that is characterized with systemic inflammation response, the production of abnormal antibodies, and persistent synovitis. One of the key mechanisms underlying the pathogenesis of RA is the imbalance of CD4 + T lymphocyte subsets, from T helper (Th) 17 cells and regulatory T (Treg) cells to T follicular helper (Tfh) cells and T follicular regulatory (Tfr) cells, which can mediate autoimmune inflammatory response to promote the overproduction of cytokines and abnormal antibodies. Although the treatment of RA has greatly changed due to the discovery of biological agents such as anti-TNF, the remission of it is still not satisfactory, thus, it is urgently required new treatment to realize the sustained remission of RA via restoring the immune tolerance. Interleukin-2 (IL-2) has been discovered to be a pleiotropic cytokine to promote inflammatory response and maintain immune tolerance. Low-dose IL-2 therapy is a driver of the imbalance between autoimmunity and immune tolerance towards immune tolerance, which has been tried to treat various autoimmune diseases. Recent researches show that low-dose IL-2 is a promising treatment for RA. In this review, we summarize the advances understandings in the biology of IL-2 and highlight the impact of the IL-2 pathway on the balance of Th17/Treg and Tfh/Tfr aiming to investigate the role of IL-2-mediated immune tolerance in RA and discuss the application and the therapeutic prospect of low-dose IL-2 in the treatment of RA.

Rheumatoid arthritis patients display B-cell dysregulation already in the na\xefve repertoire consistent with defects in B-cell tolerance

B cells are postulated to be central in seropositive rheumatoid arthritis (RA). Here, we use exploratory mass cytometry (n = 23) and next-generation sequencing (n = 19) to study B-cell repertoire shifts in RA patients. Expression of several B-cell markers were significantly different in ACPA+ RA compared to healthy controls, including an increase in HLA-DR across subsets, CD22 in clusters of IgM+ B cells and CD11c in IgA+ memory. Moreover, both IgA+ and IgG+ double negative (IgD− CD27−) CD11c+ B cells were increased in ACPA+ RA, and there was a trend for elevation in a CXCR5/CCR6high transitional B-cell cluster. In the RA BCR repertoire, there were significant differences in subclass distribution and, notably, the frequency of VH with low somatic hypermutation (SHM) was strikingly higher, especially in IgG1 (p < 0.0001). Furthermore, both ACPA+ and ACPA− RA patients had significantly higher total serum IgA and IgM compared to controls, based on serology of larger cohorts (n = 3494 IgA; n = 397 IgM). The observed elevated Ig-levels, distortion in IgM+ B cells, increase in double negative B cells, change in B-cell markers, and elevation of unmutated IgG+ B cells suggests defects in B-cell tolerance in RA. This may represent an underlying cause of increased polyreactivity and autoimmunity in RA.

Tocilizumab: Efficacy and Tolerance in Rheumatoid Arthritis in Current Practice

Introduction: The aim of this study was to evaluate in “real life” the efficacy and the tolerance of Tocilizumab (TCZ) in the treatment of rheumatoid arthritis (RA).Materials and methods: A cross-sectional study including patients with RA patients treated with TCZ at the commended dose of 8 mg/kg/ 4 weeks. The therapeutic response was evaluated by the EULAR DAS 28 ‐CRP/ VS at month 3 and month 6 of treatment.Results: RA was in most cases severe (76,5 %), seropositive (88,2 %) and erosive (81,3 %). TCZ was prescribed as an alternative to a previous biotherapy in 23 % of the patients and in monotherapy in 76, 5 % of the patients. After treatment follow-up at 3 and 6 months, the different parameters observed were significantly improved including: VAS (visual analogue scale) pain (p=0,000), CRP (mg/L) p=0,000), ESR (mmH1) (p=0,000), DAS 28 CRP (p=0,000), and DAS 28 ESR (p=0,000). Apart from a worsening of renal function in a patient contraindicated continuation of tocilizumab, no serious side effects were noted.Conclusion: Our study confirmed the efficacy and tolerance of TCZ therapy in Moroccan patients suffering from RA.Keywords: rheumatoid arthritis, tocilizumab, efficacy, tolerance

An update on research advances in rheumatoid arthritis: from clinic to basic science

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterised by breach of self-tolerance and production of autoantibodies, particularly rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA). Many events can lead to loss of tolerance in RA and they include genetic, environmental and epigenetic factors as well as post-translational modifications. Current therapies in RA tend to treat symptoms or slow down the disease progression but no cure exists at the moment. This review provides a summary of the main recent research advances regarding new therapies in RA and new studies about the effect of genetic, environment and epigenetics in this autoimmune disease. Moreover, it summarises the present knowledge about the role of “new” autoantibodies in RA focussing on anti-carbamylated protein antibodies (anti-CarP), anti-hinge antibodies, anti-acetylated protein antibodies and anti-malondialdehyde-acetaldehyde adducts (MAA) antibody. Finally, a brief summary on the recent role of Fab N-glycosylation is reported.

Autoantibodies in inflammatory arthritis.

Rheumatoid arthritis (RA) is a systemic chronic inflammatory disease characterized by extensive synovitis resulting in erosions of articular cartilage and marginal bone with joint destruction. The lack of immunological tolerance in RA represents the first step toward the development of autoimmunity. Susceptible individuals, under the influence of environmental factors, such as tobacco smoke, and silica exposure, develop autoimmune phenomena that result in the presence of autoantibodies. HLA and non-HLA haplotypes play a major role in determining the development of specific autoantibodies differentiating anti-citrullinated antibodies (ACPA)-positive and negative RA patients. Rheumatoid factor (RF) and ACPA are the serological markers for RA, and during the preclinical immunological phase, autoantibody titers increase with a progressive spread of ACPA antigens repertoire. The presence of ACPA represents an independent risk factor for developing RA in patients with undifferentiated arthritis or arthralgia. Moreover, anti-CarP antibodies have been identified in patients with RA as well as in individuals before the onset of clinical symptoms of RA. Several autoantibodies mainly targeting post-translational modified proteins have been investigated as possible biomarkers to improve the early diagnosis, prognosis and response to therapy in RA patients. Psoriatic arthritis (PsA) is distinguished from RA by infrequent positivity for RF and ACPA, together with other distinctive clinical features. Actually, specific autoantibodies have not been described. Recently, anti-CarP antibodies have been reported in sera from PsA patients with active disease. Further investigations on autoantibodies showing high specificity and sensibility as well as relevant correlation with disease severity, progression, and response to therapy are awaited in inflammatory arthritides.

Antibodies to native and citrullinated RA33 (hnRNP A2/B1) challenge citrullination as the inciting principle underlying loss of tolerance in rheumatoid arthritis

BackgroundAnti-citrullinated protein antibodies (ACPAs) are the hallmark of rheumatoid arthritis (RA). Protein citrullination is believed to drive autoantigen selection in RA. Nonetheless, several autoantigens in RA are targeted as native...

Heat Shock Proteins as Target for the Induction of Antigen-Specific Tolerance in Rheumatoid Arthritis and other Chronic Inflammatory Diseases

The critical causative factor of chronic inflammatory diseases such as rheumatoid arthritis (RA) is the faulty regulation of self-tolerance. Despite good results in patients that do respond to potent immunosuppressive therapies, in most of the cases only partial responses are achieved leaving them unduly susceptible to risks, such as infections. More importantly, immunosuppressive measures do not alter the basic condition, so that disease returns when therapy is halted. Antigen-specific therapies may represent a better and more physiological approach for manipulating the immune response avoiding the generalized immune suppression in patients and possibly leading to a state of permanent disease remission. The selection of auto-antigens without necessarily being the initiator of disease and with the ability to induce regulatory T cells is crucial for the development of antigen-specific therapies. Heat Shock Proteins (HSPs) are up-regulated during inflammation and HSP-responses are immuno-dominant. HSP-derived peptides have proved to be able to produce a shift from a pro-inflammatory to a tolerogenic phenotype in pathogenic T cells and endogenous HSP have been shown to act as targets for anti-inflammatory Tregs that control disease without general immune suppression.

Gene, environment, microbiome and mucosal immune tolerance in rheumatoid arthritis.

RA is a complex multifactorial chronic disease that transitions through several stages. Multiple studies now support that there is a prolonged phase in early RA development during which there is serum elevation of RA-related autoantibodies including RF and ACPAs in the absence of clinically evident synovitis. This suggests that RA pathogenesis might originate in an extra-articular location, which we hypothesize is a mucosal site. In discussing this hypothesis, we will present herein the current understanding of mucosal immunology, including a discussion about the generation of autoimmune responses at these surfaces. We will also examine how other factors such as genes, microbes and other environmental toxins (including tobacco smoke) could influence the triggering of autoimmunity at mucosal sites and eventually systemic organ disease. We will also propose a research agenda to improve our understanding of the role of mucosal inflammation in the development of RA.

B cell receptor signaling-based index as a biomarker for the loss of peripheral immune tolerance in autoreactive B cells in rheumatoid arthritis.

This study examines the loss of peripherally induced B cell immune tolerance in Rheumatoid arthritis (RA) and establishes a novel signaling-based measure of activation in a subset of autoreactive B cells - the Induced tolerance status index (ITSI). Naturally occurring naïve autoreactive B cells can escape the “classical” tolerogenic mechanisms of clonal deletion and receptor editing, but remain peripherally tolerized through B cell receptor (BCR) signaling inhibition (postdevelopmental “receptor tuning” or anergy). ITSI is a statistical index that numerically determines the level of homology between activation patterns of BCR signaling intermediaries in B cells that are either tolerized or activated by auto antigen exposure, and thus quantifies the level of peripheral immune tolerance. The index is based on the logistic regression analysis of phosphorylation levels in a panel of BCR signaling proteins. Our results demonstrate a new approach to identifying autoreactive B cells based on their BCR signaling features.

A Mouse Model of Adoptive Immunotherapeutic Targeting of Autoimmune Arthritis Using Allo-Tolerogenic Dendritic Cells

ObjectiveTolerogenic dendritic cells (tDCs) are immunosuppressive cells with potent tolerogenic ability and are promising immunotherapeutic tools for treating rheumatoid arthritis (RA). However, it is currently unknown whether allogeneic tDCs (allo-tDCs) induce tolerance in RA, and whether the numbers of adoptively transferred allo-tDCs, or the requirement for pulsing with relevant auto-antigens are important.MethodstDCs were derived from bone marrow precursors of C57BL/B6 mice, which were induced in vitro by GM-CSF, IL-10 and TGF-β1. Collagen-induced arthritis (CIA) was modeled in D1 mice by immunization with type II collagen (CII) to test the therapeutic ability of allo-tDCs against CIA. Clinical and histopathologic scores, arthritic incidence, cytokine and anti-CII antibody secretion, and CD4+Th subsets were analyzed.ResultstDCs were characterized in vitro by a stable immature phonotype and a potent immunosuppressive ability. Following adoptive transfer of low doses (5×105) of CII-loaded allo-tDCs, a remarkable anti-arthritic activity, improved clinical scores and histological end-points were found. Serological levels of inflammatory cytokines and anti-CII antibodies were also significantly lower in CIA mice treated with CII-pulsed allo-tDCs as compared with allo-tDCs. Moreover, treatment with allo-tDCs altered the proportion of Treg/Th17 cells.ConclusionThese findings suggested that allo-tDCs, especially following antigen loading, reduced the severity of CIA in a dose-dependent manner. The dampening of CIA was associated with modulated cytokine secretion, Treg/Th17 polarization and inhibition of anti-CII secretion. This study highlights the potential therapeutic utility of allo-tDCs in autoimmune arthritis and should facilitate the future design of allo-tDC immunotherapeutic strategies against RA.

Tolerogenic dendritic cell therapy for rheumatoid arthritis: where are we now?

Dendritic cells with tolerogenic function (tolDC) have become a promising immunotherapeutic tool for reinstating immune tolerance in rheumatoid arthritis (RA) and other autoimmune diseases. The concept underpinning tolDC therapy is that it specifically targets the pathogenic autoimmune response while leaving protective immunity intact. Findings from human in-vitro and mouse in-vivo studies have been translated into the development of clinical grade tolDC for the treatment of autoimmune disorders. Recently, two tolDC trials in RA and type I diabetes have been carried out and other trials are in progress or are imminent. In this review, we provide an update on tolDC therapy, in particular in relation to the treatment of RA, and discuss the challenges and the future perspectives of this new experimental immunotherapy.