Antigen-specific Fab profiling achieves molecular-resolution analysis of human autoantibody repertoires in rheumatoid arthritis.

The presence of autoantibodies is a defining feature of many autoimmune diseases. The number of unique autoantibody clones is conceivably limited by immune tolerance mechanisms, but unknown due to limitations of the currently applied technologies. Here, we introduce an autoantigen-specific liquid chromatography-mass spectrometry-based IgG1 Fab profiling approach using the anti-citrullinated protein antibody (ACPA) repertoire in rheumatoid arthritis (RA) as an example. We show that each patient harbors a unique and diverse ACPA IgG1 repertoire dominated by only a few antibody clones. In contrast to the total plasma IgG1 antibody repertoire, the ACPA IgG1 sub-repertoire is characterised by an expansion of antibodies that harbor one, two or even more Fab glycans, and different glycovariants of the same clone can be detected. Together, our data indicate that the autoantibody response in a prominent human autoimmune disease is complex, unique to each patient and dominated by a relatively low number of clones.

Biomaterial-based combinatorial approach of aescin-comprised zein-coated gelatin nanoparticles alleviates synovial inflammation in experimental inflammatory arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that mostly affects joints. Although RA therapy has made significant progress, difficulties including extensive medication metabolism and its quick clearance result in its inadequate bioavailability. The anti-inflammatory effect of zein was reported with other medications, but it has certain limitations. There are reports on the anti-oxidant and anti-inflammatory effect of aescin, which exhibits low bioavailability for the treatment of rheumatoid arthritis. Also, the combinatorial effect of zein with other effective drug delivery systems is still under investigation for the treatment of experimental collagen-induced rheumatoid arthritis. The focus of this study was to formulate and define the characteristics of zein-coated gelatin nanoparticles encapsulated with aescin (Ze@Aes-GNPs) and to assess and contrast the therapeutic effectiveness of Ze@Aes-GNPs towards collagen-induced RA in Wistar rats. Nanoprecipitation and the layer-by-layer coating process were used to fabricate Ze@Aes-GNPs and their hydrodynamic diameter was determined to be 182 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to further validate the size, shape, and surface morphology of Ze@Aes-GNPs. When tested against foreskin fibroblasts (BJ), these nanoparticles demonstrated significantly high cytocompatibility. Both Aes and Ze@Aes-GNPs were effective in treating arthritis, as shown by the decreased edoema, erythema, and swelling of the joints, between which Ze@Aes-GNPs were more effective. Further, it was demonstrated that Aes and Ze@Aes-GNPs reduced the levels of oxidative stress (articular elastase, lipid peroxidation, catalase, superoxide dismutase and nitric oxide) and inflammatory indicators (TNF-α, IL-1ß and myeloperoxidase). The histopathology findings further demonstrated that Ze@Aes-GNPs considerably reduced the infiltration of inflammatory cells at the ankle joint cartilage compared to Aes. Additionally, immunohistochemistry examination showed that treatment with Ze@Aes-GNPs suppressed the expression of pro-inflammatory markers (COX-2 and IL-6) while increasing the expression of SOD1. In summary, the experiments indicated that Aes and Ze@Aes-GNPs lowered the severity of arthritis, and critically, Ze@Aes-GNPs showed better effectiveness in comparison to Aes. This suppression of oxidative stress and inflammation was likely driven by Aes and Ze@Aes-GNPs.

Central sensitivity syndrome affects the disease activity index and treatment satisfaction in patients with rheumatoid arthritis.

AIM: Many rheumatoid arthritis (RA) patients prioritize pain improvement in treatment. As pain can result from various causes, including noninflammatory factors such as central sensitivity syndrome (CSS), we hypothesized that CSS might impact treatment satisfaction. In this cross-sectional study, we assessed the CSS effects on clinical disease activity and treatment satisfaction in RA patients. METHODS: In total, 220 consecutive RA patients receiving long-term follow-up were evaluated for clinical disease activity and treatment satisfaction. CSS was evaluated using the Central Sensitization Inventory (CSI). An overall score of ≥40 indicates the presence of CSS. We queried "How satisfied are you with your treatment?"; answers included (a) very satisfied, (b) satisfied, (c) not satisfied, or (d) very dissatisfied. For univariate analysis, we condensed these answers into "dissatisfied" or "satisfied." We also evaluated treatment satisfaction using the visual analog scale (VAS), with scores ranging from 0 mm (very dissatisfied) to 100 mm (very satisfied). RESULTS: Of the 220 patients, 17 (7.7%) were classified as having CSS. CSI score was significantly correlated with the clinical disease activity index (CDAI; r = .322, p < .01) and treatment satisfaction (r = -.336, p < .01). Regarding treatment satisfaction, univariate analysis revealed that patient global assessment (PtGA), pain VAS, Health Assessment Questionnaire-Disability Index (HAQ-DI), Disease Activity Score in 28 joints with C-reactive protein, CDAI, and CSI scores of patients who were satisfied with treatment differed significantly from those of dissatisfied patients. Multivariate analysis revealed that CSI, PtGA, and HAQ-DI scores were associated with treatment satisfaction. CONCLUSION: In RA patients, CSS may affect the disease activity index and reduce treatment satisfaction.

Accelerated biological aging as a potential risk factor for rheumatoid arthritis.

OBJECTS: Previous studies have suggested a potential correlation between rheumatoid arthritis (RA) and biological aging, but the intricate connections and mechanisms remain elusive. METHODS: In our study, we focused on two specific measures of biological age (PhenoAge and BioAge), which are derived from clinical biomarkers. The residuals of these measures, when compared to chronological age, are defined as biological age accelerations (BAAs). Utilizing the extensive UK Biobank dataset along with various genetic datasets, we conducted a thorough assessment of the relationship between BAAs and RA at both the individual and aggregate levels. RESULTS: Our observational studies revealed positive correlations between the two BAAs and the risk of developing both RA and seropositive RA. Furthermore, the genetic risk score (GRS) for PhenoAgeAccel was associated with an increased risk of RA and seropositive RA. Linkage disequilibrium score regression (LDSC) analysis further supported these findings, revealing a positive genetic correlation between PhenoAgeAccel and RA. PLACO analysis identified 38 lead pleiotropic single nucleotide polymorphisms linked to 301 genes, providing valuable insights into the potential mechanisms connecting PhenoAgeAccel and RA. CONCLUSION: In summary, our study has successfully revealed a positive correlation between accelerated biological aging, as measured by BAAs, and the susceptibility to RA.

Classification of rheumatoid arthritis: is it time to revise the criteria?

Classification criteria have been developed for rheumatoid arthritis (RA) and other rheumatic diseases in order to gather a homogeneous patient population for clinical studies and facilitate the timely implementation of therapeutic measures. Although classification criteria are not intended to be used for diagnosis, they are frequently used to support the diagnostic process in clinical practice, including clinical decision-making. The 2010 American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) classification criteria for RA are capable of identifying the majority of symptomatic patients with RA already in the earliest stages of the disease who are not yet showing radiographic changes. These patients will also profit from the early implementation of therapy with disease-modifying antirheumatic drugs (DMARDs). However, the risk of misclassification is higher as compared with the former 1987 ACR criteria, which were considerably less sensitive to the recognition of patients with early RA. Of note, the presence of rheumatoid factors (RFs) and anticitrullinated protein antibodies (ACPAs) has been attributed equal weight in the 2010 ACR/EULAR criteria and may contribute up to 50% of the score needed for being classified as RA. However, while ACPAs have been proven to be the most specific serological markers of RA, the specificity of RF is moderate, especially at lower titres. This may lead to the misclassification of RF-positive patients and, consequently, the unjustified implementation of DMARD therapy. Therefore, issues arise on how comprehensive the criteria should be and whether they should be updated and adapted to findings from the past two decades that might increase both their specificity and sensitivity.

Predictors of quality of life, functional status, depression and fatigue in early arthritis: comparison between clinically suspect arthralgia, unclassified arthritis and rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is often preceded by symptomatic phases during which classification criteria are not fulfilled. The health burden of these "at-risk" stages is not well described. This study assessed health-related quality of life (HRQoL), function, fatigue and depression in newly presenting patients with clinically suspect arthralgia (CSA), unclassified arthritis (UA) or RA. METHODS: Cross-sectional analysis of baseline Patient-Reported Outcome Measures (PROMs) was conducted in patients from the Birmingham Early Arthritis Cohort. HRQoL, function, depression and fatigue at presentation were assessed using EQ-5D, HAQ-DI, PHQ-9 and FACIT-F. PROMs were compared across CSA, UA and RA and with population averages from the HSE with descriptive statistics. Multivariate linear regression assessed associations between PROMs and clinical and sociodemographic variables. RESULTS: Of 838 patients included in the analysis, 484 had RA, 200 had CSA and 154 had UA. Patients with RA reported worse outcomes for all PROMs than those with CSA or UA. However, "mean EQ-5D utilities were 0.65 (95%CI: 0.61 to 0.69) in CSA, 0.61 (0.56 to 0.66) in UA and 0.47 (0.44 to 0.50) in RA, which was lower than in general and older (≥ 65 years) background populations." In patients with CSA or UA, HRQoL was comparable to chronic conditions such as heart failure, severe COPD or mild angina. Higher BMI and older age (≥ 60 years) predicted worse depression (PHQ-9: -2.47 (-3.85 to -1.09), P < 0.001) and fatigue (FACIT-F: 5.05 (2.37 to 7.73), P < 0.001). Women were more likely to report worse function (HAQ-DI: 0.13 (0.03 to 0.21), P = 0.01) and fatigue (FACIT-F: -3.64 (-5.59 to -1.70), P < 0.001), and residents of more deprived areas experienced decreased function (HAQ-DI: 0.23 (0.10 to 0.36), P = 0.001), greater depression (PHQ-9: 1.89 (0.59 to 3.18), P = 0.004) and fatigue (FACIT-F: -2.60 (-5.11 to 0.09), P = 0.04). After adjustments for confounding factors, diagnostic category was not associated with PROMs, but disease activity and polypharmacy were associated with poorer performance across all PROMs. CONCLUSIONS: Patient-reported outcomes were associated with disease activity and sociodemographic characteristics. Patients presenting with RA reported a higher health burden than those with CSA or UA, however HRQoL in the pre-RA groups was significantly lower than population averages.

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

OBJECTIVE: This 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 (RA). METHODS: This report included 793 participants with untreated early RA from the randomised, longitudinal NORD-STAR trial, all of whom had their body mass index (BMI) assessed at baseline. Obesity was defined as BMI ≥30 kg/m2. All participants were randomised 1:1:1:1 to one of four treatment arms: active conventional treatment, certolizumab-pegol, abatacept and tocilizumab. Clinical and laboratory measurements were performed at baseline and at 8, 12, 24 and 48-week follow-up. The primary endpoint for this report was response to treatment based on Clinical Disease Activity Index (CDAI) and Simple Disease Activity Index (SDAI) remission and Disease Activity Score with 28 joints using C-reactive protein (DAS28-CRP) <2.6 stratified by BMI. RESULTS: Out of 793 people included in the present report, 161 (20%) had obesity at baseline. During follow-up, participants with baseline obesity had higher disease activity compared with those with lower BMI, despite having similar disease activity at baseline. In survival analyses, obesity was associated with a lower likelihood of achieving response to treatment during follow-up for up to 48 weeks (CDAI remission, HR 0.84, 95% CI 0.67 to 1.05; SDAI, HR 0.77, 95% CI 0.62 to 0.97; DAS28-CRP <2.6, HR 0.78, 95% CI 0.64 to 0.95). The effect of obesity on response to treatment was not influenced by the treatment arms. CONCLUSION: In people with untreated early RA followed up for up to 48 weeks, obesity was associated with a lower likelihood of good treatment response, irrespective of the type of randomised treatment received. TRIAL REGISTRATION NUMBER: NCT01491815.

Utility of testing for third-generation anticyclic citrullinated peptide (anti-CCP3) antibodies in individuals who present with new musculoskeletal symptoms but have a negative second-generation anticyclic citrullinated peptide (anti-CCP2) antibody test.

OBJECTIVES: To investigate the role of third-generation anticyclic citrullinated peptide (anti-CCP3) antibodies in predicting progression to inflammatory arthritis (IA) in individuals with new musculoskeletal (MSK) symptoms and a negative second-generation anti-CCP antibody test (anti-CCP2-). METHODS: 469 anti-CCP2- individuals underwent baseline anti-CCP3 testing (QUANTA Lite CCP3; Inova Diagnostics) and received a post enrolment 12-month questionnaire. A rheumatologist confirmed or excluded diagnosis of IA. Univariable/multivariable analyses were performed to assess the value of anti-CCP3 in predicting IA development in these anti-CCP2- individuals. RESULTS: Only 16/469 (3.4%) anti-CCP2- individuals had a positive anti-CCP3 test. Of these 16 individuals, 4 developed IA. In addition, 61/469 (13.0%) anti-CCP2- individuals self-reported, to have developed, IA. Progression was confirmed in 43/61 of them (70.5%); of whom 30/43 (69.8%) and 13/43 (30.2%) were given a diagnosis of IA and rheumatoid arthritis (RA), respectively. In qualitative univariable analysis, anti-CCP3 positivity was associated with self-reported progression (p<0.01) and IA (p=0.03), but not with RA. Anti-CCP3 levels differed significantly between progressors and non-progressors (p<0.01) for all three categories. At the manufacturer's cut-off, OR for progression ranged from 2.4 (95% CI 0.5 to 18.6; RA) to 7.5 (95% CI 2.3 to 24.0; self-reported progression). Interestingly, when cut-offs for anti-CCP3 were optimised, lower values (≥5 units) significantly increased the OR for progression in all three categories. In multivariable analysis, anti-CCP3 positivity at the manufacturer's cut-off did not remain associated with IA progression, while this lower cut-off value (≥5 units) was associated with diagnosis of RA (p=0.02). CONCLUSIONS: Anti-CCP3 testing could improve the prediction of IA development in anti-CCP2- individuals with new MSK symptoms.

Comparison of active tuberculosis occurrence associated with Janus kinase inhibitors and biological DMARDs in rheumatoid arthritis.

OBJECTIVES: This study aimed to evaluate the risk of tuberculosis associated with the use of Janus kinase (JAK) inhibitors or biological disease-modifying antirheumatic drugs (bDMARDs) in patients diagnosed with rheumatoid arthritis (RA) in South Korea. METHODS: In this nationwide matched-cohort study, we retrospectively identified adult patients with new-onset RA from the National Health Insurance Service database who were prescribed bDMARDs or JAK inhibitors and recently underwent latent tuberculosis infection (LTBI) screening during 2012‒2021, and followed them up until the end of 2022 for the development of active tuberculosis. HRs were estimated using Cox proportional hazards regression in a propensity score-matched cohort. RESULTS: Among 16 760 matched patients with RA (3352 JAK inhibitor users and 13 408 bDMARD users), 18.8% received tuberculosis preventive therapy for LTBI. Overall, JAK inhibitor users had a significantly lower risk of tuberculosis than bDMARD users (HR (95% CI)=0.37 (0.22 to 0.62)). Among the patients treated for LTBI, patients with low treatment adherence had a significantly higher risk than those without LTBI (HR (95% CI)=2.78 (1.74 to 4.44)). Patients without LTBI and using JAK inhibitors had a significantly lower risk of tuberculosis across all ages and sexes compared with bDMARD users. CONCLUSION: Patients with RA using JAK inhibitors have a significantly lower risk of active tuberculosis than bDMARD users in South Korea; however, patients with RA having LTBI are equally at risk regardless of the treatment received (JAK inhibitor vs bDMARD). Therefore, vigilant tuberculosis monitoring, especially in patients with low adherence to tuberculosis preventive therapy, is essential.

Understanding the psychosocial determinants of effective disease management in rheumatoid arthritis to prevent persistently active disease: a qualitative study.

BACKGROUND: According to epidemiological studies, psychosocial factors are known to be associated with disease activity, physical activity, pain, functioning, treatment help-seeking, treatment waiting times and mortality in people with rheumatoid arthritis (RA). Limited qualitative inquiry into the psychosocial factors that add to RA disease burden and potential synergistic interactions with biological parameters makes it difficult to understand patients' perspectives from the existing literature. AIM: This study aimed to gather in-depth patient perspectives on psychosocial determinants that drive persistently active disease in RA, to help guide optimal patient care. METHODS: Patient research partners collaborated on the research design and materials. Semistructured interviews and focus groups were conducted online (in 2021) with patients purposively sampled from diverse ethnicities, primary languages, employment status and occupations. Data were analysed using inductive thematic analysis. RESULTS: 45 patients participated across 28 semistructured interviews and three focus groups. Six main themes on psychosocial determinants that may impact RA management were identified: (1) healthcare systems experiences, (2) patient education and health literacy, (3) employment and working conditions, (4) social and familial support, (5) socioeconomic (dis)advantages, and (6) life experiences and well-being practices. CONCLUSION: This study emphasises the importance of clinicians working closely with patients and taking a holistic approach to care that incorporates psychosocial factors into assessments, treatment plans and resources. There is an unmet need to understand the relationships between interconnected biopsychosocial factors, and how these may impact on RA management.

Development and validation of the rheumatoid arthritis scale among the system of quality of life instruments for chronic diseases QLICD-RA (V2.0).

Rheumatoid Arthritis is a more serious threatening to people and suitable for QOL measurement. A few specific QOL instruments are available without considering Chinese culture. The present study was aimed to develop and validate the Rheumatoid Arthritis Scale among the System of Quality of Life Instruments for Chronic Diseases (QLICD-RA V2.0). The data collected from 379 patients with RA was used to evaluate the psychometric properties of the scale. The reliability was evaluated by the internal consistency Cronbach's α, test-retest reliability Pearson correlation r and intra-class correlation (ICC). We evaluated the construct validity and criteria-related validity by correlation analysis and structural equation modeling. We compared the differences in scores of QLICD-RA before and after treatment and used the Standard Response Mean (SRM) to assess the responsiveness. The results showed that the internal consistency coefficient Cronbach's α values were greater than 0.70. The correlations r and ICCs were greater than 0.80. The correlation analysis and structural equation modeling confirmed good construct validity and criterion-related validity. The SRM ranges from 0.07 to 0.27 for significant domains/facets. It concluded that QLICD-RA (2.0) is a reliable and valid instrument to measure QOL among patients with RA.

CCR9+CD4+ T cells are associated with disease activity in patients with rheumatoid arthritis.

An increase in CD4+ T cells in the synovium is closely linked to the pathogenesis of rheumatoid arthritis (RA). We aimed to identify the possible causes of the elevated CD4+ T cell levels and to explore the factors influencing disease activity in RA. Fifty-five RA patients, including 28 with active RA (ARA), 27 with inactive RA, and 22 healthy controls, were recruited for this study. The proportion of CCR9+CD4+ T cells and the expression of chemokine receptor 9 (CCR9) on CD4+ T cells were analyzed by flow cytometry. Enzyme-linked immunosorbent assay and chemiluminescent immunoassay were used to evaluate interleukin (IL)-17A and IL-6 levels, respectively. The proportion of CCR9+CD4+ T cells and the expression of CCR9 on CD4+ T cells increased significantly in peripheral blood (PB) and synovial fluid (SF) in ARA compared to those in inactive RA. Furthermore, SF contained more CCR9+CD4+ T cells, IL-6, and IL-17A than PB in RA patients. Moreover, CD4+ T cells in the PB of patients with RA, especially ARA, expressed more CCR9 and secreted more IL-6 and IL-17A after activation. Here, we also demonstrated that both the percentage of CCR9+ cells in CD4+ T cells and the expression of CCR9 on circulating CD4+ T cells were positively correlated with erythrocyte sedimentation rate, hypersensitive C-reactive protein, rheumatoid factor, and anti-cyclic citrullinated peptide antibody. CCR9+CD4+ T cells are elevated in PB and SF, and are associated with disease activity in patients with RA.

Autoimmune diseases and their genetic link to bronchiectasis: insights from a genetic correlation and Mendelian randomization study.

Background: Previous studies have demonstrated that autoimmune diseases are closely associated with bronchiectasis (BE). However, the causal effects between autoimmune diseases and BE remain elusive. Methods: All summary-level data were obtained from large-scale Genome-Wide Association Studies (GWAS). The univariate Mendelian randomization (UVMR) was utilized to investigate the genetic causal correlation (rg) of 12 autoimmune diseases and bronchiectasis, The Multivariable Mendelian Randomization (MVMR) method was used to explore the effects of the confounding factors. Further investigation was conducted to identify potential intermediate factors using mediation analysis. Finally, the linkage disequilibrium score regression (LDSC) method was used to identify genetic correlations among complex traits. A series of sensitivity analyses was performed to validate the robustness of the results. Results: The LDSC analysis revealed significant genetic correlations between BE and Crohn's disease (CD) (rg = 0.220, P = 0.037), rheumatoid arthritis (RA) (rg = 0.210, P = 0.021), and ulcerative colitis (UC) (rg = 0.247, P = 0.023). However, no genetic correlation was found with other autoimmune diseases (P > 0.05). The results of the primary IVW analysis suggested that for every SD increase in RA, there was a 10.3% increase in the incidence of BE (odds ratio [OR] = 1.103, 95% confidence interval [CI] 1.055-1.154, P = 1.75×10-5, FDR = 5.25×10-5). Furthermore, for every standard deviation (SD) increase in celiac disease (CeD), the incidence of BE reduced by 5.1% (OR = 0.949, 95% CI 0.902-0.999, P = 0.044, FDR = 0.044). We also observed suggestive evidence corresponding to a 3% increase in BE incidence with T1DM (OR = 1.033, 95% CI 1.001-1.066, P = 0.042, FDR = 0.063). Furthermore, MVMR analysis showed that RA was an independent risk factor for BE, whereas mediator MR analysis did not identify any mediating factors. The sensitivity analyses corroborated the robustness of these findings. Conclusion: LDSC analysis revealed significant genetic correlations between several autoimmune diseases and BE, and further MVMR analysis showed that RA is an independent risk factor for BE.

Hydroxychloroquine-induced hyperpigmentation of the skin and bull's-eye maculopathy in rheumatic patients: a case report and literature review.

Hydroxychloroquine (HCQ) is used as a traditional disease-modifying antirheumatic drugs (DMARDs), for the treatment of autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). However, it can cause serious adverse reactions, including hyperpigmentation of the skin and bull's-eye macular lesions. Here, we present a case of HCQ-induced hyperpigmentation of the skin and bull's-eye macular lesions in a patient who received HCQ for RA. A 65-year-old female patient developed blurred vision and hyperpigmentation of multiple areas of skin over the body for one month after 3 years of HCQ treatment for RA. Based on clinical presentation, ophthalmological examination and dermatopathological biopsy, a diagnosis of drug-induced cutaneous hyperpigmentation and bullous maculopathy of the right eye was made. After discontinuation of HCQ and treatment with iguratimod tablets, the hyperpigmentation of the patient 's skin was gradually reduced, and the symptoms of blurred vision were not significantly improved. We also reviewed the available literature on HCQ-induced cutaneous hyperpigmentation and bull's-eye macular lesions and described the clinical features of HCQ-induced cutaneous hyperpigmentation and bull's-eye macular lesions. In conclusion, clinicians should be aware of early cutaneous symptoms and HCQ-associated ophthalmotoxicity in patients with rheumatic diseases on HCQ sulphate and should actively monitor patients, have them undergo regular ophthalmological examinations and give appropriate treatment to prevent exacerbation of symptoms.

Unveiling the link between lactate metabolism and rheumatoid arthritis through integration of bioinformatics and machine learning.

Rheumatoid arthritis (RA) is a persistent autoimmune condition characterized by synovitis and joint damage. Recent findings suggest a potential link to abnormal lactate metabolism. This study aims to identify lactate metabolism-related genes (LMRGs) in RA and investigate their correlation with the molecular mechanisms of RA immunity. Data on the gene expression profiles of RA synovial tissue samples were acquired from the gene expression omnibus (GEO) database. The RA database was acquired by obtaining the common LMRDEGs, and selecting the gene collection through an SVM model. Conducting the functional enrichment analysis, followed by immuno-infiltration analysis and protein-protein interaction networks. The results revealed that as possible markers associated with lactate metabolism in RA, KCNN4 and SLC25A4 may be involved in regulating macrophage function in the immune response to RA, whereas GATA2 is involved in the immune mechanism of DC cells. In conclusion, this study utilized bioinformatics analysis and machine learning to identify biomarkers associated with lactate metabolism in RA and examined their relationship with immune cell infiltration. These findings offer novel perspectives on potential diagnostic and therapeutic targets for RA.

Macrophage-derived mir-100-5p orchestrates synovial proliferation and inflammation in rheumatoid arthritis through mTOR signaling.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by synovial inflammation, causing substantial disability and reducing life quality. While macrophages are widely appreciated as a master regulator in the inflammatory response of RA, the precise mechanisms underlying the regulation of proliferation and inflammation in RA-derived fibroblast-like synoviocytes (RA-FLS) remain elusive. Here, we provide extensive evidence to demonstrate that macrophage contributes to RA microenvironment remodeling by extracellular vesicles (sEVs) and downstream miR-100-5p/ mammalian target of rapamycin (mTOR) axis. RESULTS: We showed that bone marrow derived macrophage (BMDM) derived-sEVs (BMDM-sEVs) from collagen-induced arthritis (CIA) mice (cBMDM-sEVs) exhibited a notable increase in abundance compared with BMDM-sEVs from normal mice (nBMDM-sEVs). cBMDM-sEVs induced significant RA-FLS proliferation and potent inflammatory responses. Mechanistically, decreased levels of miR-100-5p were detected in cBMDM-sEVs compared with nBMDM-sEVs. miR-100-5p overexpression ameliorated RA-FLS proliferation and inflammation by targeting the mTOR pathway. Partial attenuation of the inflammatory effects induced by cBMDM-sEVs on RA-FLS was achieved through the introduction of an overexpression of miR-100-5p. CONCLUSIONS: Our work reveals the critical role of macrophages in exacerbating RA by facilitating the transfer of miR-100-5p-deficient sEVs to RA-FLS, and sheds light on novel disease mechanisms and provides potential therapeutic targets for RA interventions.

C-reactive protein lowers the serum level of IL-17, but not TNF-α, and decreases the incidence of collagen-induced arthritis in mice.

The biosynthesis of C-reactive protein (CRP) in the liver is increased in inflammatory diseases including rheumatoid arthritis. Previously published data suggest a protective function of CRP in arthritis; however, the mechanism of action of CRP remains undefined. The aim of this study was to evaluate the effects of human CRP on the development of collagen-induced arthritis (CIA) in mice which is an animal model of autoimmune inflammatory arthritis. Two CRP species were employed: wild-type CRP which binds to aggregated IgG at acidic pH and a CRP mutant which binds to aggregated IgG at physiological pH. Ten CRP injections were given on alternate days during the development of CIA. Both wild-type and mutant CRP reduced the incidence of CIA, that is, reduced the number of mice developing CIA; however, CRP did not affect the severity of the disease in arthritic mice. The serum levels of IL-17, IL-6, TNF-α, IL-10, IL-2 and IL-1ß were measured: both wild-type and mutant CRP decreased the level of IL-17 and IL-6 but not of TNF-α, IL-10, IL-2 and IL-1ß. These data suggest that CRP recognizes and binds to immune complexes, although it was not clear whether CRP functioned in its native pentameric or in its structurally altered pentameric form in the CIA model. Consequently, ligand-complexed CRP, through an as-yet undefined mechanism, directly or indirectly, inhibits the production of IL-17 and eventually protects against the initiation of the development of arthritis. The data also suggest that IL-17, not TNF-α, is critical for the development of autoimmune inflammatory arthritis.

Abatacept increases T cell exhaustion in early RA individuals who carry HLA risk alleles.

Exhausted CD8 T cells (TEX) are associated with worse outcome in cancer yet better outcome in autoimmunity. Building on our past findings of increased TIGIT+KLRG1+ TEX with teplizumab therapy in type 1 diabetes (T1D), in the absence of treatment we found that the frequency of TIGIT+KLRG1+ TEX is stable within an individual but differs across individuals in both T1D and healthy control (HC) cohorts. This TIGIT+KLRG1+ CD8 TEX population shares an exhaustion-associated EOMES gene signature in HC, T1D, rheumatoid arthritis (RA), and cancer subjects, expresses multiple inhibitory receptors, and is hyporesponsive in vitro, together suggesting co-expression of TIGIT and KLRG1 may broadly define human peripheral exhausted cells. In HC and RA subjects, lower levels of EOMES transcriptional modules and frequency of TIGIT+KLRG1+ TEX were associated with RA HLA risk alleles (DR0401, 0404, 0405, 0408, 1001) even when considering disease status and cytomegalovirus (CMV) seropositivity. Moreover, the frequency of TIGIT+KLRG1+ TEX was significantly increased in RA HLA risk but not non-risk subjects treated with abatacept (CTLA4Ig). The DR4 association and selective modulation with abatacept suggests that therapeutic modulation of TEX may be more effective in DR4 subjects and TEX may be indirectly influenced by cellular interactions that are blocked by abatacept.

Exploring the Correlation between Interleukin-17A Promoter Polymorphism at its -197 G/A and Rheumatoid Arthritis: Impact on Disease Severity and Activity.

T helper 17 (Th17) cells have been reported to be the most powerful factor in autoimmune disorder pathogenesis, which points to the Th17 master cytokine, interleukin (IL)-17A, as the crucial mediator. We aimed to determine the impact of IL-17A polymorphism in the -197 G/A promoter region on level of IL-17 and intensity of rheumatoid arthritis (RA) disease symptoms. This case-control study was conducted at the Department of Clinical Rheumatology of Aswan university Hospital and included 35 people suffering RA and 30 volunteer controls, matched for age and sex. Rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibodies, erythrocyte sedimentation rate (ESR), serum IL-17, and C-reactive protein (CRP) were measured in the RA patient group. Restriction fragment length polymorphism (RFLP) was conducted by polymerase chain reaction (PCR) amplicon obtained by IL-17A -197 G /A primers. Of the 35 RA patients, RF was positive in 33 (94.29%) and anti-CCP antibodies in 25 (71.43%), CRP in 31 (88.57%). Of the 35 RA patients, 5 (14.29%) patients carried the G/G genotype, 18 (51.43%) G/A and 12 (34.29%) A/A. IL-17 serum level was significantly greater in the more active RA (DAS28 >5.1) group than the less active (DAS28 ≤5.1) group. Of the RA patients carrying wild type G/G genotype, 60% had more active disease (DAS 28> 5.1), as compared to those with lower activity (DAS 28 ≤5.1), 40% carried the wild type G/G genotype. In conclusion, the study findings imply that IL-17A gene polymorphism is connected to RA clinical severity rather than with RA susceptibility.