Untreated Rheumatoid Arthritis Research Articles

JAK inhibitors attenuate hyperactivation of nonswitched memory B cells in rheumatoid arthritis patients in remission

ObjectiveTo investigate the distribution and activation of B-cell subpopulations in rheumatoid arthritis (RA) patients treated with Janus kinase inhibitors (JAKis) and to analyze their correlation with disease remission.MethodsPeripheral blood samples were collected from 23 adult healthy controls and 58 RA patients, 31 of whom were treated with JAKis and assessed during a 24-month follow-up. The number of peripheral B-cell subpopulations (including naive B cells, nonswitched memory B (NSMB) cells, switched memory B cells, and double-negative B cells), their activation, and phosphorylation of SYK and AKT upon B-cell receptor (BCR) stimulation in each population were analyzed by flow cytometry.ResultsCompared with that in healthy controls, the frequency of NSMB cells was significantly lower in new-onset untreated RA patients. However, expression of CD40, CD80, CD95, CD21low and pAKT significantly increased in these NSMB cells. Additionally, the number of NSMB cells correlated negatively with DAS28-ESR and IgG and IgA levels in these patients; expression of CD80, CD95 and CD21low on NSMB cells correlated positively with DAS28-ESR and IgG and IgA levels. After treatment with JAKis, the serum IgG concentration significantly decreased in RA patients in remission, but CD40, CD95 and pAKT levels in NSMB cells significantly decreased.ConclusionRA patients present different B-cell subpopulations, in which the frequency of NSMB cells is negatively associated with disease activity. However, treatment with JAKis can inhibit activation of NSMB cells, restore the balance of kinase phosphorylation, and facilitate disease remission in RA patients.

Correlation of Professional Antigen-Presenting Tbet+CD11c+ B Cells With Bone Destruction in Untreated Rheumatoid Arthritis.

Subsets of CD21-/low memory B cells (MBCs), including double-negative (DN, CD27-IgD-) and Tbet+CD11c+ cells, are expanded in chronic inflammatory diseases. In rheumatoid arthritis (RA), CD21-/low MBCs correlate with joint destruction. However, whether this is due to the Tbet+CD11c+ subset, its function and pathogenic contribution to RA are unknown. This study aims to investigate the association between CD21-/lowTbet+CD11c+ MBCs and joint destruction as well as other clinical parameters and to elucidate their functional properties in patients with untreated RA (uRA). Clinical observations were combined with flow cytometry (n = 36) and single-cell RNA sequencing (scRNA-seq) and V(D)J sequencing (n = 4) of peripheral blood (PB) MBCs from patients with uRA. The transcriptome of circulating Tbet+CD11c+ MBCs was compared with scRNA-seq data of synovial B cells. In vitro coculture of Tbet+CD11c+ B cells with T cells was used to assess costimulatory capacity. CD21-/lowTbet+CD11c+ MBCs in PB correlated with bone destruction but no other clinical parameters analyzed. The Tbet+CD11c+ MBCs have undergone clonal expansion and express somatically mutated V genes. Gene expression analysis of these cells identified a unique signature of more than 150 up-regulated genes associated with antigen presentation functions, including B cell receptor activation and clathrin-mediated antigen internalization; regulation of actin filaments, endosomes, and lysosomes; antigen processing, loading, presentation, and costimulation; a transcriptome mirrored in their synovial tissue counterparts. In vitro, Tbet+CD11c+ B cells induced retinoic acid receptor-related orphan nuclear receptor γT expression in CD4+ T cells, thereby polarizing to Th17 cells, a T cell subset critical for osteoclastogenesis and associated with bone destruction. This study suggests that Tbet+CD11c+ MBCs contribute to the pathogenesis of RA by promoting bone destruction through antigen presentation, T cell activation, and Th17 polarization.

Assessing sleep-related breathing disorders among newly diagnosed rheumatoid and psoriatic arthritis patients: a cross-sectional study.

This cross-sectional study aimed to determine the prevalence and risk factors for sleep-related breathing disorders (SRBD) in newly diagnosed, untreated rheumatoid arthritis (RA) and psoriatic arthritis (PsA) patients, and to develop a screening algorithm for early detection. We evaluated newly diagnosed RA or PsA patients using the Epworth Sleepiness Scale (ESS) questionnaire, cardiorespiratory polygraphy (RPG), and clinical and laboratory assessments. Sleep apnea syndrome (SAS) was diagnosed based on pathological RPG findings excessive daytime sleepiness, defined as ESS score above 10. The study included 39 patients (22 RA, 17 PsA) and 23 controls. In RPG, SRBD was identified in 38.5% of arthritis patients compared to 39.1% of controls (p = 1.00), with male gender (p = .004) and age (p < .001) identified as risk factors. Excessive daytime sleepiness was noted in 36.4% of RA patients, 17.6% of PsA patients, and 21.7% of controls. Of the 24 patients diagnosed with SRBD, 41.6% met the criteria for SAS. SAS prevalence was 31.8% among RA patients, 0% in PsA patients, and 13% in controls. A significant association was observed between excessive daytime sleepiness and SRBD (p = .036). Our findings reveal a high prevalence of SRBD in newly diagnosed, untreated RA and PsA patients in ESS and RPG, with excessive daytime sleepiness being a reliable predictor of SRBD. Patients with RA exhibited a higher predisposition to SAS. We therefore suggest incorporating ESS and RPG as screening tools in RA or PsA for early detection and management of SRBD.

CD14+ Dendritic-Shaped Cells Functioning as Dendritic Cells in Rheumatoid Arthritis Synovial Tissues.

We previously reported that CD14+ dendritic-shaped cells exhibit a dendritic morphology, engage in pseudo-emperipolesis with lymphocytes, and express CD90 in the perivascular areas of rheumatoid arthritis (RA) synovial tissues. However, it remains unclear whether these CD14highCD90intermediate(int) cells function as dendritic cells. In this study, we investigated the dendritic cell-differentiation potential of CD14highCD90int cells. The localization and number of CD14highCD90int cells in RA synovial tissues and peripheral blood were examined. The dendritic cell-differentiation potential of CD14highCD90int cells was examined by measuring interleukin-6 and tumor necrosis factor-α levels in the supernatant and CD83 and human leukocyte antigen (HLA)-DR expression in the cells after induction of dendritic cell differentiation. Synovial cells were co-cultured with lymphocytes, and the activation of these cells was examined. CD14highCD90int cells were abundant in RA synovial tissues, including the sublining layer and the pannus areas. Patients with untreated and active RA had significantly higher percentages of CD14highCD90int cells in the peripheral blood and synovial tissues. In RA synovial cells, inflammatory cytokine levels increased with dendritic cell-differentiation culture, but CD83 and HLA-DR expression were significantly increased in the CD14highCD90int cell group. When co-cultured with lymphocytes, cell numbers and inflammatory cytokine levels significantly increased in both groups of synovial cells after dendritic cell induction. CD14+ cells migrate and spread from the circulating blood to RA synovial tissues while expressing CD90, and CD14highCD90int cells in contact with lymphocytes differentiate into HLA-DR+ dendritic cells, which contribute to chronic inflammation in RA.

Synovial fibroblast gene expression is associated with sensory nerve growth and pain in rheumatoid arthritis.

It has been presumed that rheumatoid arthritis (RA) joint pain is related to inflammation in the synovium; however, recent studies reveal that pain scores in patients do not correlate with synovial inflammation. We developed a machine-learning approach (graph-based gene expression module identification or GbGMI) to identify an 815-gene expression module associated with pain in synovial biopsy samples from patients with established RA who had limited synovial inflammation at arthroplasty. We then validated this finding in an independent cohort of synovial biopsy samples from patients who had early untreated RA with little inflammation. Single-cell RNA sequencing analyses indicated that most of these 815 genes were most robustly expressed by lining layer synovial fibroblasts. Receptor-ligand interaction analysis predicted cross-talk between human lining layer fibroblasts and human dorsal root ganglion neurons expressing calcitonin gene-related peptide (CGRP+). Both RA synovial fibroblast culture supernatant and netrin-4, which is abundantly expressed by lining fibroblasts and was within the GbGMI-identified pain-associated gene module, increased the branching of pain-sensitive murine CGRP+ dorsal root ganglion neurons in vitro. Imaging of solvent-cleared synovial tissue with little inflammation from humans with RA revealed CGRP+ pain-sensing neurons encasing blood vessels growing into synovial hypertrophic papilla. Together, these findings support a model whereby synovial lining fibroblasts express genes associated with pain that enhance the growth of pain-sensing neurons into regions of synovial hypertrophy in RA.

Obesity is a risk factor for poor response to treatment in early rheumatoid arthritis: a NORD-STAR study

ObjectiveThis report from the NORD-STAR (Nordic Rheumatic Diseases Strategy Trials and Registries) trial aimed to determine if obesity is associated with response to conventional and biological antirheumatic treatment in early...

Rheumatoid Arthritis: Current and Emerging Paradigms of Diagnosis and Treatment

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by inflammation and damage to joints andtissues. While previous reviews exist, there still needs to be more in understanding risk factors, diagnostic methods, and treatmentoptions. This review aims to fill these gaps by providing a comprehensive overview of recent advancements in the field. To addressthe limitations of previous reviews, this article incorporates updated information on risk factors, including the influence ofenvironmental factors in industrialized nations. It highlights the significance of early RA diagnosis and emphasizes the utility ofdynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for effective disease management. Moreover, this reviewintroduces innovative nanotechnology-based treatment approaches for RA. It explores the potential of gold nanoparticles, carbonnanotubes, polymer-based nanomedicine, and nanoliposomes in targeting specific inflammatory sites and improving treatmenteffectiveness. This review aims to present an up-to-date and comprehensive analysis of RA, bridging gaps in previous literature byintroducing novel diagnostic techniques and exploring emerging treatment modalities. By synthesizing current knowledge andoutlining future research prospects, this review aims to advance the understanding and treatment of rheumatoid arthritis.Additionally, this review discusses the systemic complications associated with RA, such as rheumatoid vasculitis and Feltysyndrome. It also sheds light on the long-term consequences of untreated RA, including the potential need for joint replacementsurgery (arthroplasty) and splenectomy. By providing a comprehensive analysis of these aspects, this review aims to enhance theholistic understanding of RA and guide future research toward improved management and patient outcomes.

Disease activity drives transcriptomic heterogeneity in early untreated rheumatoid synovitis

ObjectivesTranscriptomic profiling of synovial tissue from patients with early, untreated rheumatoid arthritis (RA) was used to explore the ability of unbiased, data-driven approaches to define clinically relevant subgroups.MethodsRNASeq was performed...

Differential expression and correlation of immunoregulation related piRNA in rheumatoid arthritis.

Although PIWI-interacting RNAs (piRNAs) have recently been associated with germline development and many human diseases, their expression pattern and relationship in autoimmune diseases remain indistinct. This study aimed to investigate the presence and correlation of piRNAs in rheumatoid arthritis (RA). We first analyzed the expression profile of piRNAs using small RNA sequencing in peripheral leukocytes of three new-onset untreated RA patients and three healthy controls (HCs). We then selected piRNAs related to immunoregulation by bioinformatics analysis and verified them in 42 new-onset RA patients and 81 HCs by RT-qPCR. Furthermore, a receiver operating characteristic curve was generated to quantify the diagnostic performance of these piRNAs. A correlation analysis was conducted to observe the link between piRNA expression and RA clinical characteristics. A total of 15 upregulated and 9 downregulated piRNAs among 1,565 known piRNAs were identified in peripheral leukocytes of RA patients. Dysregulated piRNAs were enriched in numerous pathways related to immunity. After selection and validation, two immunoregulation piRNAs (piR-hsa-27620 and piR-hsa-27124) were significantly elevated in RA patients and have good abilities to distinguish patients from controls, which have the potential to serve as biomarkers. PIWI and other proteins implicated in the piRNA pathway were also associated with RA.

Rheumatoid arthritis.

It is difficult to determine from ancient writings, old human specimens, and from Art over the centuries, as to when Rheumatoid Arthritis first appeared. It may be a relatively modern condition, as it was reasonably well described in the seventeenth century. Augustin Jacob Landre-Beauvais (1772-1840), University of Paris is credited, with the first clear description of the disease in his thesis. In 1859 Sir Alfred Baring Garrod (1819-1907), the "father of rheumatology", gave the disease its current name which was finally adapted in Britain by the Ministry of Health in 1922. Some forms of Juvenile Arthritis are related to adult Rheumatoid Arthritis (aka Still's disease). If untreated Rheumatoid arthritis can result in severe destructive joint damage and often there are associated severe systemic complications. Disease modifying agents have benefited the disease management, but it was the discovery of the anti TNF-alpha agents in the 1990s, and subsequently many additional Biologic agents, which have greatly changed the clinical outcome in Rheumatoid Arthritis.

P114 Exploring micro-RNA content of circulating extracellular vesicles as biomarkers in early rheumatoid arthritis

Abstract Background/Aims Early diagnosis and prompt and effective intervention for people with immune-mediated inflammatory diseases (IMIDs) such as rheumatoid arthritis (RA) improves outcomes. Non-invasive biomarkers that reflect unique aspects of underlying biology could facilitate this. Extracellular vesicles (EVs) released by many cell types are abundantly present in body fluids where they contribute to intercellular signalling by transferring cargo including microRNAs (miRs) - themselves implicated in disease pathogenesis. We investigated whether serum EV miR expression (i) discriminates patients with newly presenting, untreated RA from those with an alternative IMID or none, (ii) predicts therapeutic response to first-line methotrexate (MTX) treatment amongst RA patients, or, in the same individuals (iii) exhibit dynamically altered expression in MTX-responders versus non-responders during treatment. Methods Using a validated protocol, serum EVs were isolated from 43 early RA patients. Identically isolated EV were available from sera of 23 newly presenting, untreated polymyalgia rheumatica (PMR, “IMID control”) patients and 12 “non-inflammatory control” patients (NICs) in whom significant inflammatory disease had been excluded. miRs were isolated and subject to NanoString sequencing (798 miRs). Following quality control, DESeq2 was first used to identify miRs uniquely deregulated in RA EVs at baseline. Within the early RA cohort, a baseline comparison between individuals who subsequently achieved clinical remission after 6 months treatment with MTX (DAS28-CRP&amp;lt;2.4 without having required systemic steroids in preceding 2 months) and those that did not, was also undertaken by partial least squared-discriminant analysis (PLS-DA) with 5-fold cross validation. Linear modelling was used to assess differences in dynamic EV miR expression between responders and non-responders. Multiple test correction was applied (false discovery rate; FDR). Results A signature of 28 miRs uniquely differentially expressed between early RA patients and NICs (i.e. not also between PMR and NICs) was identified, which was robust to MTC after correction for age and sex. Amongst those upregulated in RA were miR-337-3p, whose predicted target proteins include Jak2 and STAT3, and miR-144-3p, recently shown to mediate the expression of pro-inflammatory cytokines and chemokines by macrophages. Whilst EV miRs differentially expressed at baseline between RA patients who subsequently achieved early MTX-induced remission and those who did not were not robust to MTC, PLS-DA indicated their predictive potential. Finally, several miRs whose change in expression over the course of treatment differed significantly between responders and non-responders; namely miR-548ar-3p, miR-212-3p, miR-188-5p, miR-410-3p, and miR-338-5p amongst others, may offer insight into the mechanism of MTX’s therapeutic action. Conclusion Serum EV miRs are a possible source of clinically valuable biomarkers that may shed light on pathophysiology and/or mechanisms of MTX efficacy. Our findings highlight their potential as diagnostic and prognostic tools in early RA. Larger studies and validation in independent cohorts are warranted to pursue this potential, alongside mechanistic evaluation. Disclosure D. Maunder: None. P.M. Brown: None. B. Barron-Millar: None. D. Lendrem: None. N. Naamane: None. J. Macdonald: None. X. Wang: None. A.E. Anderson: None. A.W. Morgan: None. S.L. Mackie: Consultancies; Roche/Chugai, Sanofi, AbbVie and AstraZeneca. Honoraria; Pfizer, Vifor and UCB. Grants/research support; Vifor. R. Crossland: None. A.G. Pratt: Consultancies; Inflection Biosciences.

Reduction of Proinflammatory Effector Functions Through Remodeling of Fatty Acid Metabolism in CD8+ T Cells From Rheumatoid Arthritis Patients.

Rheumatoid arthritis (RA) CD8+ T cells maintain their effector proinflammatory phenotype by changing their metabolism toward aerobic glycolysis. However, their massive energy and biosynthesis needs may require additional substrates other than glucose. Since systemic alterations in lipid metabolism have been reported in RA patients, we explored the role of fatty acid (FA) metabolism in CD8+ T cells to identify potential targets to curb their proinflammatory potential. The expression of FA metabolism-related genes was analyzed for total CD8+ T cells and CD8+ T cell subsets in the data of RA patients and healthy controls retrieved from the GEO database. Functional assays were performed using peripheral blood CD8+ T cells isolated from RA (n=31), psoriatic arthritis (n=26), and spondyloarthritis (n=21) patients receiving different therapies (disease-modifying antirheumatic drugs, biologics, and JAK inhibitors) and from healthy controls (n=14). We quantified the expression of FA transporters, lipid uptake, intracellular FA content, cytokine production, activation, proliferation, and capacity to inhibit tumor cell growth, either with or without FA metabolism inhibitors. The CD8+ T cell gene expression profile of FA metabolism-related genes was significantly different between untreated RA patients and healthy controls. RA patients who had a good clinical response after 6 months of methotrexate therapy had significantly increased expression of FA metabolism-related genes. Cell surface expression of the FA transporters FA binding protein 4 (FABP4) and G protein-coupled receptor 84 (GPR84) and FA uptake were higher in effector and memory CD8+ T cells from RA patients compared to those from healthy controls. In vitro blockade of FA metabolism significantly impaired CD8+ T cell effector functions. RA CD8+ T cells present an altered FA metabolism, which could provide potential therapeutic targets to control their proinflammatory profile, particularly therapies directed against the transport and oxidation of free FA.

Radiographic airway abnormalities in untreated early rheumatoid arthritis are associated with peripheral neutrophil activation

BackgroundThe role of the lung for the initiation and progression of rheumatoid arthritis (RA) is still unclear. Up to 10% of RA patients develop interstitial lung disease which remains a clinical challenge. Understanding early disease mechanisms is of great importance. The objective of this study was to determine whether there is an association between peripheral neutrophil phenotypes and presence of pulmonary abnormalities (PA) on chest high-resolution computed tomography (HRCT) in untreated early RA (ueRA).MethodsClinical data and blood were collected, and HRCT performed at diagnosis on 30 consecutive anti-citrullinated protein antibody (ACPA) and/or rheumatoid factor (RF) positive ueRA patients. HRCTs were evaluated for the presence of RA-associated parenchymal, airway and/or pleural abnormalities. Expression of phenotype markers on neutrophils were determined by flow cytometry. Levels of calprotectin, ACPA and RF were measured using immunoassays.ResultsThe frequency of having any PA was 60%. Airway abnormalities were present in 50%, parenchymal nodules in 43% and interstitial lung abnormalities (ILA) in 10%. Unsupervised multivariate data analysis showed clustering of any PA with neutrophil activation, parameters of inflammation and RF titres. In univariate analysis, the patients with PA displayed significantly increased CD11b and decreased CD62L expression on neutrophils (1.2-fold, p = 0.014; 0.8-fold, p = 0.012) indicating activation and significantly increased RF IgM titre and CRP (5.7-fold, p = 0.0025; 2.3-fold, p = 0.0035) as compared to no PA. Titres of RF, but not ACPA, correlated with expression of the neutrophil activation marker CD11b. A stratified analysis demonstrated that airway involvement was the PA subtype with the strongest association with neutrophil activation.ConclusionWe report a strong association between radiographic airway findings and activation of circulating neutrophils in early RA supporting a role of innate immunity and the lung at disease onset. Our results also indicate different contributions of RF and ACPA in the RA pathogenesis.

77 - Lymphoid interstitial pneumonia in a patient with untreated rheumatoid arthritis

77 - Lymphoid interstitial pneumonia in a patient with untreated rheumatoid arthritis

Dynamics of circulating follicular helper T cell subsets and follicular regulatory T cells in rheumatoid arthritis patients according to HLA-DRB1 locus.

B cells, follicular helper T (Tfh) cells and follicular regulatory T (Tfr) cells are part of a circuit that may play a role in the development or progression of rheumatoid arthritis (RA). With the aim of providing further insight into this topic, here we evaluated the frequency of different subsets of Tfh and Tfr in untreated and long-term treated RA patients from a cohort of Argentina, and their potential association with particular human leukocyte antigen (HLA) class-II variants and disease activity. We observed that the frequency of total Tfh cells as well as of particular Tfh subsets and Tfr cells were increased in seropositive untreated RA patients. Interestingly, when analyzing paired samples, the frequency of Tfh cells was reduced in synovial fluid compared to peripheral blood, while Tfr cells levels were similar in both biological fluids. After treatment, a decrease in the CCR7loPD1hi Tfh subset and an increase in the frequency of Tfr cells was observed in blood. In comparison to healthy donors, seropositive patients with moderate and high disease activity exhibited higher frequency of Tfh cells while seropositive patients with low disease activity presented higher Tfr cell frequency. Finally, we observed that HLA-DRB1*09 presence correlated with higher frequency of Tfh and Tfr cells, while HLA-DRB1*04 was associated with increased Tfr cell frequency. Together, our results increase our knowledge about the dynamics of Tfh and Tfr cell subsets in RA, showing that this is altered after treatment.

The proportion and phenotypic changes of CD4+CD25−Foxp3+ T cells in patients with untreated rheumatoid arthritis

ObjectiveCD4+CD25+Foxp3+ regulatory T (Treg) cell-mediated immunosuppression is an essential mechanism of rheumatoid arthritis (RA). However, little is known regarding the specific role of CD4+CD25−Foxp3+ Treg cells in RA. This study aimed to investigate the frequency of circulating CD4+CD25−Foxp3+ Treg cells and their role in RA.MethodsSixty-one untreated RA patients and 40 healthy controls (HCs) were enrolled in this study. The proportion of CD4+CD25−Foxp3+ T cells and CD4+CD25+Foxp3+ Tregs; the levels of CTLA4, GITR, Helios, and ICOS; and the production of IL-17A, IFN-γ, and IL-10 were assessed by flow cytometry. The correlation of CD4+CD25–Foxp3+ T cells and CD4+CD25+Foxp3+ Tregs with the clinical indicators was conducted by Spearman correlation analysis.ResultsThe proportion of CD4+CD25–Foxp3+ T cells was elevated in RA and positively correlated with disease activity. CD4+CD25–Foxp3+ T cells expressed less Helios and produced more IFN-γ than conventional Tregs in RA. Additionally, the proportion of CD4+CD25–Foxp3+ T cells was positively correlated with DAS28 score, IgG titer, and anti-CCP titer.ConclusionsThese data indicate that CD4+CD25−Foxp3+ T cells in RA exhibit several different functional properties from conventional Tregs and are correlated with RA disease activity.

Functional Role of Novel Anthranilic Acid Derivatives as Anti-inflammatory Agents

Abstract: Background: The discovery of new cyclooxygenase (COX) inhibitors with high efficacy and safety would be a great achievement in developing anti-inflammatory drugs. This study evaluated the anti-inflammatory activity and the expected side effect of two synthesized anthranilic acid derivatives (JS-3 and JS-4). Materials and Methods: The COX selectivity of compounds was assessed in a whole blood assay. The results were confirmed by molecular docking studies. In vivo anti-inflammatory activity was tested in complete Freund’s adjuvant (CFA)-induced rheumatoid arthritis (RA) in rats. The safety profile was determined by administering a dose three times the therapeutic dose. Results: In vitro COX-2 selectivity of JS-4 was higher than JS-3 (13.70 vs. 5.56). Docking studies supported the higher selectivity of both derivatives against COX-2 than mefenamic acid. Treatment of CFA-arthritic rats with both compounds showed significant (P < 0.01) decreases in paw volume, paw thickness, arthritic index, and inflammatory parameters such as rheumatoid factor, interleukin (IL)-1β, IL-6, prostaglandin (PG) E2, PGI2, and TXB2 compared to untreated RA animals. JS-3 and JS-4 improved synovial joint histopathology and protected against RA-induced pathological changes: splenomegaly, thymomegaly, and cardiomyopathy. Both derivatives produced minimal effects on liver and renal functions, without any ulcerogenic effects. Conclusion: These results suggest that JS-4 is a potential and safe candidate for managing RA without renal, liver, gastrointestinal, or cardiovascular toxicity. Keywords: Cyclooxygenase inhibitors, Anthranilic acid derivatives, Mefenamic acid, Rheumatoid arthritis, Anti-inflammatory, Safety evaluation, Molecular docking.

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

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

Integrated single cell and spatial transcriptomics reveal autoreactive differentiated B cells in joints of early rheumatoid arthritis

B cells play a significant role in established Rheumatoid Arthritis (RA). However, it is unclear to what extent differentiated B cells are present in joint tissue already at the onset of disease. Here, we studied synovial biopsies (n = 8) captured from untreated patients at time of diagnosis. 3414 index-sorted B cells underwent RNA sequencing and paired tissue pieces were subjected to spatial transcriptomics (n = 4). We performed extensive bioinformatics analyses to dissect the local B cell composition. Select plasma cell immunoglobulin sequences were expressed as monoclonal antibodies and tested by ELISA. Memory and plasma cells were found irrespective of autoantibody status of the patients. Double negative memory B cells were prominent, but did not display a distinct transcriptional profile. The tissue architecture implicate both local B cell maturation via T cell help and plasma cell survival niches with a strong CXCL12–CXCR4 axis. The immunoglobulin sequence analyses revealed clonality between the memory B and plasma cell pools further supporting local maturation. One of the plasma cell-derived antibodies displayed citrulline autoreactivity, demonstrating local autoreactive plasma cell differentiation in joint biopsies captured from untreated early RA. Hence, plasma cell niches are not a consequence of chronic inflammation, but are already present at the time of diagnosis.

Altered Transcriptional Regulation of Glycolysis in Circulating CD8+ T Cells of Rheumatoid Arthritis Patients.

Peripheral T lymphocytes of rheumatoid arthritis (RA) patients show pathological changes in their metabolic pathways, especially glycolysis. These changes may drive the increased proliferation and tissue invasiveness of RA T cells. In order to study the transcriptional regulation underlying these alterations, we analysed publicly available RNA sequencing data from circulating T lymphocyte subsets of healthy individuals, untreated RA patients, and patients undergoing treatment for RA. Differential co-expression networks were created using sample-wise edge weights from an analysis called “linear interpolation to obtain network estimates for single sample” (lionessR), and annotated using the Gene Transcription Regulation Database (GTRD). Genes with high centrality scores were identified. CD8+ effector memory cells (Tem) and CD8+CD45RA+ effector memory cells (Temra) showed large changes in the transcriptional regulation of glycolysis in untreated RA. PFKFB3 and GAPDH were differentially regulated and had high centrality scores in CD8+ Tem cells. PFKFB3 downregulation may be due to HIF1A post transcriptional inhibition. Tocilizumab treatment partially reversed the RA-associated differential expression of several metabolic and regulatory genes. MYC was upregulated and had high centrality scores in RA CD8+ Temra cells; however, its glycolysis targets were unaltered. The upregulation of the PI3K-AKT and mTOR pathways may explain MYC upregulation.