Immune Rheumatoid Arthritis Research Articles

Target Role of Monocytes as Key Cells of Innate Immunity in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic, systemic, and inflammatory autoimmune condition characterized by synovitis, pannus formation (with adjacent bone erosion), and joint destruction. In the perpetuation of RA, fibroblast-like synoviocytes (FLSs), macrophages, B cells, and CD4+ T-cells-specifically Th1 and Th17 cells-play crucial roles. Additionally, dendritic cells, neutrophils, mast cells, and monocytes contribute to the disease progression. Monocytes, circulating cells primarily derived from the bone marrow, participate in RA pathogenesis. Notably, CCR2 interacts with CCL2, and CX3CR1 (expressed by monocytes) cooperates with CX3CL1 (produced by FLSs), facilitating the migration involved in RA. Canonical "classical" monocytes predominantly acquire the phenotype of an "intermediate" subset, which differentially expresses proinflammatory cytokines (IL-1β, IL-6, and TNF) and surface markers (CD14, CD16, HLA-DR, TLRs, and β1- and β2-integrins). However, classical monocytes have greater potential to differentiate into osteoclasts, which contribute to bone resorption in the inflammatory milieu; in RA, Th17 cells stimulate FLSs to produce RANKL, triggering osteoclastogenesis. This review aims to explore the monocyte heterogeneity, plasticity, antigenic expression, and their differentiation into macrophages and osteoclasts. Additionally, we investigate the monocyte migration into the synovium and the role of their cytokines in RA.

Analyzation of the Peripheral Blood Mononuclear Cells Atlas and Cell Communication of Rheumatoid Arthritis Patients Based on Single-Cell RNA-Seq.

Rheumatoid arthritis (RA) is a common chronic inflammatory autoimmune disease with a multifactorial etiology. Peripheral blood is the main channel of the immune system, and peripheral blood mononuclear cells (PBMCs) are the immune cells that initiate the autoimmune inflammatory process. However, there are few reports on the mechanisms of peripheral blood immunity in RA. ScRNA-seq was performed on four RA samples and integrated with single-cell transcriptome data from four healthy control samples downloaded from publicly available databases for analysis. A total of 52,073 cells were used for descending clustering analysis to map RA peripheral blood immune cells at single-cell resolution. Redimensional clustering analysis of four major immune cells (T cells, monocytes, B cells, and natural killer cells) revealed that double-negative T (DNT) cells were significantly altered in abundance and function. And a number of genes (including SOCS3, cAMP-responsive element modulator (CREM), B2M, MTFP1, RSRP1, and YWHAB) were specifically downregulated in DNT cells. RA T cells, especially DNT cells, exhibit significant metabolic defects and dysfunction, mainly in the form of inhibition of oxidative phosphorylation, ATP synthesis, and major histocompatibility complex (MHC)-I-mediated antigen presentation. In addition, cellular communication networks were established, and it was evident that RA is significantly attenuated in the number and intensity of cellular communication. Monocytes and T cells play key roles in the process of the immune inflammatory response through CCL and MHC-related pathways. This study describes the landscape of the peripheral blood immune system and cell communication in RA, characterizes the abundance of PBMCs, gene expression profiles, and changes in signaling pathways in RA patients, and identifies several key cell subpopulations (DNT and classic monocytes) and specific genes (SOCS3, CREM, B2M, MTFP1, RSRP1, and YWHAB). Meanwhile, we propose that classic monocytes in peripheral blood may migrate to sites of inflammation in synovial tissue under the chemotaxis of the chemokines CCL3 and CCL3L1, differentiate into macrophages, secrete proinflammatory cytokines, and thus participate in the inflammatory response. These findings provide new insights for the future elucidation of the peripheral blood immune mechanisms of RA and the search for new clinical therapeutic targets.

Interleukin 26 Induces Macrophage IL-9 Expression in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is an autoimmune disease with chronic inflammation, bone erosion, and joint deformation. Synovial tissue in RA patients is full of proinflammatory cytokines and infiltrated immune cells, such as T help (Th) 9, Th17, macrophages, and osteoclasts. Recent reports emphasized a new member of the interleukin (IL)-10 family, IL-26, an inducer of IL-17A that is overexpressed in RA patients. Our previous works found that IL-26 inhibits osteoclastogenesis and conducts monocyte differentiation toward M1 macrophages. In this study, we aimed to clarify the effect of IL-26 on macrophages linking to Th9 and Th17 in IL-9 and IL-17 expression and downstream signal transduction. Murine and human macrophage cell lines and primary culture cells were used and stimulated by IL26. Cytokines expressions were evaluated by flow cytometry. Signal transduction and transcription factors expression were detected by Western blot and real time-PCR. Our results show that IL-26 and IL-9 colocalized in macrophage in RA synovium. IL-26 directly induces macrophage inflammatory cytokines IL-9 and IL-17A expression. IL-26 increases the IL-9 and IL-17A upstream mechanisms IRF4 and RelB expression. Moreover, the AKT-FoxO1 pathway is also activated by IL-26 in IL-9 and IL-17A expressing macrophage. Blockage of AKT phosphorylation enhances IL-26 stimulating IL-9-producing macrophage cells. In conclusion, our results support that IL-26 promotes IL-9- and IL-17-expressing macrophage and might initiate IL-9- and IL-17-related adaptive immunity in rheumatoid arthritis. Targeting IL-26 may a potential therapeutic strategy for rheumatoid arthritis or other IL-9 plus IL-17 dominant diseases.

Role of biochemical markers in rheumatoid arthritis

Rheumatoid arthritis is the most common chronic, progressive systemic inflammatory arthritis of unknown cause. It affects approximately 1-2% of the population worldwide. It is a form of autoimmune disease principally synovial tissues. As the pathophysiology involves affecting cell mediated immune response, adenosine deaminase may have a role in rheumatoid arthritis. As it involves bones and joints, it is likely that it alters the levels of Serum Calcium, Phosphorus and Magnesium as well as Alkaline Phosphatase which may be helpful in diagnosis or management of the disease. 1. To evaluate the role of serum adenosine deaminase (ADA) as a marker of cell mediated immunity in Rheumatoid Arthritis. 2. To estimate serum alkaline phosphatase, calcium, phosphorus and magnesium as prognostic markers of Rheumatoid arthritisA cross-sectional, case control study with convenient sampling was undertaken after Institutional Ethical Clearance & informed consent. 30 patients of Rheumatoid Arthritis presenting to the orthopaedic outpatient department of Owaisi Hospital and Research Centre, Hyderabad were taken as cases along with an equal number of age and sex matched controls from January 2021 to June 2021. ADA levels were estimated by colorimetric assay on ErbaChem 7 semiautoanalyser. Serum Alkaline phosphatase, Calcium, Phosphorus and Magnesium were estimated on Cobas C311 autoanalyzer. There was a significant increase in levels of Adenosine Deaminase, Alkaline Phosphatase and Serum Phosphorus, while the levels of Calcium and Magnesium were significantly reduced in rheumatoid arthritisADA as a marker of cell mediated immunity reflects monocyte / macrophage activity and was increased in our study suggesting immunological and inflammatory process in the pathogenesis of Rheumatoid Arthritis (R.A). It can be used as a non invasive marker of chronic inflammation and may provide additional information about disease prognosis.Increased levels of Alkaline Phosphatase and Phosphorus associated with low Calcium and Magnesium suggest increased bone resorption in R. A and are useful as markers of disease activity.

The N-Formyl Peptide Receptors and Rheumatoid Arthritis: A Dangerous Liaison or Confusing Relationship?

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by a progressive symmetric inflammation of the joints resulting in bone erosion and cartilage destruction with a progressive loss of function and joint deformity. An increased number of findings support the role of innate immunity in RA: many innate immune mechanisms are responsible for producing several cytokines and chemokines involved in RA pathogenesis, such as Tumor Necrosis Factor (TNF)-α, interleukin (IL)-6, and IL-1. Pattern recognition receptors (PRRs) play a crucial role in modulating the activity of the innate arm of the immune response. We focused our attention over the years on the expression and functions of a specific class of PRR, namely formyl peptide receptors (FPRs), which exert a key function in both sustaining and resolving the inflammatory response, depending on the context and/or the agonist. We performed a broad review of the data available in the literature on the role of FPRs and their ligands in RA. Furthermore, we queried a publicly available database collecting data from 90 RA patients with different clinic features to evaluate the possible association between FPRs and clinic-pathologic parameters of RA patients.

Microbial Influences of Mucosal Immunity in Rheumatoid Arthritis

This review will summarize recent data defining the relationship between rheumatoid arthritis (RA) and the microbiome at mucosal sites throughout the body. It will highlight what is known, what is speculated, and current knowledge gaps regarding the microbiome in RA. An extensive relationship between the microbiome and immune cell function can influence RA-related inflammation and T cell and B cell biology. Studies are beginning to characterize microbial changes in individuals who are at risk for RA, which is a critical element needed to understand the influence of the microbiome on RA pathogenesis. Expanding our understanding of the microbiome in RA beyond the bacteria at the gut and oral mucosae into the lung and urogenital surfaces, including viral and fungal components, and establishing the relationship across mucosal sites will be critical in future work. Importantly, approaches to manipulate the microbiome could lead to novel therapeutic and preventive strategies.

One year in review 2020: pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease influenced by both genetic, epigenetic and environmental factors. The discovery of new gene polymorphisms and their association with disease susceptibility have added new elements to better clarify RA pathogenesis. In the last year, important elements have been added to the current knowledge of mechanisms regulating innate and adaptive immunity in RA, leading to discovering new targets for the development of disease-modifying therapies. Thus, in this review we summarise the new insights resulting from a literature research data published in the last year.

Technical comment on "Synovial fibroblast-neutrophil interactions promote pathogenic adaptive immunity in rheumatoid arthritis".

Reassessment of citrullinome cargo in neutrophil extracellular traps confirms the presence of citrullinated peptides.

Indices of cell-mediated immunity in rheumatoid arthritis: the role of cytomegalovirus infection.

The pathogenesis of rheumatoid arthritis (RA) is driven by a combined action of genetic and environmental factors, which can upset the balance between the effector and regulatory components of the immune system. An important actor in maintaining such balance is T cells, especially regulatory T lymphocytes (Treg), but the mechanisms behind the functioning of T cell subpopulations and the roles of individual etiological factors in RA have not been fully elucidated. This study aimed to investigate the indices of cell-mediated immunity, especially T- and Treg cells, in RA patients depending on the disease activity and presence of cytomegalovirus (CMV) infection. The expression of membrane and intracellular molecular markers of lymphocytes was estimated by multicolor flow cytometry. The content of antibodies to CMV in blood plasma was measured by enzyme immunoassays. Patients with RA had reliably reduced numbers of cells with the phenotypes CD4+FOXP3+, CD4+CD25+FOXP3+ correlating with the stage of RA activity. RA patients with CMV infection showed a reduction in the number of regulatory T cells (Treg), CD3+ T lymphocytes, CD3+CD8+ cells in peripheral blood. At the same time, RA involved a rise in the level of B cells and CD4+CD25+ Т cells. The level of antibodies to CMV was observed to grow in line with RA activity. Thus, the data obtained suggest that the presence of CMV infection can significantly influence the state of individual lymphocyte subpopulations during RA development.

Restored and Enhanced Memory T Cell Immunity in Rheumatoid Arthritis After TNFα Blocker Treatment.

TNFα inhibitors have shaped the landscape of rheumatoid arthritis (RA) therapy with high clinical efficiency. However, their impact on T cell recall responses is not well-elucidated. We aimed to analyze the immune profiles of memory T cells in RA patients undergoing TNFα inhibitor Golimumab (GM) treatment. Frequencies of peripheral T cell subsets and cytokine expression profiles in memory T cells (TM) upon PMA/Ionomycine stimulation were determined by flow cytometry. Antigen-specific CD8 T cell immunity was analyzed through stimulating PBMCs with CMV-EBV-Flu (CEF) viral peptide pool and subsequent intracellular IFNγ staining. Both peripheral CD8 and CD4 T cells from GM treated patients had a shift pattern characterized by an enlarged effector TM and a reduced central TM cell population when compared to GM untreated group. An increase in the frequencies of TNFα+, IL-2+, and IL-17+ CD8 TM cells was observed whereas only TNFα+CD4 TM cells increased in GM treated patients. Moreover, GM treated patients contained more peripheral IFNγ-producing CD8 T cells specific to CEF viral peptides. Together, these results show a distinct T cell subset pattern and enhanced memory T cell immunity upon GM treatment, suggesting an immunoregulatory effect of TNF inhibitor Golimumab on peripheral memory T cell responses.

Impact of synthetic and biological immunomodulatory therapy on the duration of 17DD yellow fever vaccine-induced immunity in rheumatoid arthritis

BackgroundThe 17DD-yellow fever (YF) vaccine induces a long-lasting protective immunity, resulting from humoral and cellular immunological memory. The treatment of rheumatoid arthritis (RA) patients with disease-modifying anti-rheumatic drugs (DMARD) may affect pre-existing 17DD-vaccine protective immunity and increase the risk of acquiring YF infection. Our goal was to determine whether DMARD would affect the duration of YF-specific protective immunity in RA patients.MethodsA total of 122 RA patients, previously immunized with the 17DD-YF vaccine (1–5, 5–9, and ≥ 10 years) and currently under DMARD therapy, were enrolled in the present investigation. Immunomodulatory therapy encompasses the use of conventional synthetic DMARD alone (csDMARD) or combines with biological DMARD (cs+bDMARD). A total of 226 healthy subjects were recruited as a control group (CONT). Neutralizing antibody responses were measured by a plaque-reduction neutralization test (PRNT), and cellular immunity was evaluated by an in vitro 17DD-YF-specific peripheral blood lymphoproliferative assay.ResultsThe data demonstrated that csDMARD therapy did not affect the duration of protective immunity induced by the 17DD-YF vaccine compared to that of CONT, as both presented a significant time-dependent decline at 10 years after vaccination. Conversely, cs+bDMARD therapy induced a premature depletion in the main determinants of the vaccine protective response, with diminished PRNT seropositivity levels between 5 and 9 years and impaired effector memory in CD8+ T cells as early as 1–5 years after 17DD-YF vaccination.ConclusionsThese findings could support changing the vaccination schedule of this population, with the possibility of a planned booster dose upon the suspension of bDMARD in cases where this is allowed, even before 10 years following 17DD-YF vaccination. The benefit of a planned booster dose should be evaluated in further studies.Trial registrationRBR-946bv5. Date of registration: March 05, 2018. Retrospectively registered

ACPA mediates the interplay between innate and adaptive immunity in rheumatoid arthritis.

The production of anti-citrullinated peptide antibodies (ACPAs) requires the participation of both innate immunity and adaptive immunity. On the one hand, activated innate immunity is able to produce citrullinated auto-antigens that fuel autoimmunity and provide an inflammatory environment that facilitates the breach of self-tolerance, proliferation of self-reactive T/B cells and the production of ACPAs. On the other hand, after their production by plasma B cells, ACPAs are also able to interact with innate immunity to exacerbate the manifestation and chronicity of rheumatoid arthritis (RA). This article discusses the roles of citrullinated peptides and ACPA played in innate immunity and autoimmunity. In addition, we emphasise the relationships between environmental factors and innate immunity, as well as the pathogenic function of ACPAs per se. In doing so, we hope to provide fundamental knowledge of RA pathogenesis and reveal potential therapeutic targets in RA treatment.

Comment on "Synovial fibroblast-neutrophil interactions promote pathogenic adaptive immunity in rheumatoid arthritis".

Discrepancies on the role of citrullination in the induction of experimental arthritis by neutrophils extracellular traps.

Response to comment on "Synovial fibroblast-neutrophil interactions promote pathogenic adaptive immunity in rheumatoid arthritis".

The citrullinome cargo in neutrophil extracellular traps varies according to disease condition and stimulation conditions.

Modulation of the immune response in rheumatoid arthritis with strategically released rapamycin.

Rheumatoid arthritis (RA) is a chronic inflammatory disease, which is associated with symptoms, including synovial membrane inflammatory pain, joint synovitis and stiffness. However, there are no effective methods available to cure this disease. In the present study, rapamycin was used to modulate immunity in RA. To limit the cytotoxicity of rapamycin, rapamycin was loaded into well-characterized biocompatible nanoparticles. In vitro, rapamycin particles downregulated the activation of dendritic cell surface markers, including CD80+ and CD40+, upon interacting with macrophages. The rapamycin particles reduced the secretion of inflammatory cytokines, including interleukin (IL)-6, tumor necrosis factor (TNF) and IL-1β, which are characteristic of RA. In vivo, the rapamycin particles decreased the symptoms of RA in mice, and the production of inflammatory cytokines was associated with the occurrence of RA. The present study partially revealed the interactions between rapamycin and two types of immune cell in RA disease, and may potentially offer a solution to improve the treatment of RA.

Synovial fibroblast-neutrophil interactions promote pathogenic adaptive immunity in rheumatoid arthritis.

Rheumatoid arthritis (RA) is characterized by synovial joint inflammation and by development of pathogenic humoral and cellular autoimmunity to citrullinated proteins. Neutrophil extracellular traps (NETs) are a source of citrullinated autoantigens and activate RA synovial fibroblasts (FLS), cells crucial in joint damage. We investigated the molecular mechanisms by which NETs promote proinflammatory phenotypes in FLS, and whether these interactions generate pathogenic anti-citrulline adaptive immune responses. NETs containing citrullinated peptides are internalized by FLS through a RAGE-TLR9 pathway promoting FLS inflammatory phenotype and their upregulation of MHC class II. Once internalized, arthritogenic NET-peptides are loaded into FLS MHC class II and presented to Ag-specific T cells. HLADRB1*0401 transgenic mice immunized with mouse FLS loaded with NETs develop antibodies specific to citrullinated forms of relevant RA autoantigens implicated in RA pathogenesis as well as cartilage damage. These results implicate FLS as mediators in RA pathogenesis, through the internalization and presentation of NET citrullinated peptides to the adaptive immune system leading to pathogenic autoimmunity and cartilage damage.

Endothelial Dysfunction and Inflammation: Immunity in Rheumatoid Arthritis

Inflammation, as a feature of rheumatoid arthritis (RA), leads to the activation of endothelial cells (ECs). Activated ECs induce atherosclerosis through an increased expression of leukocyte adhesion molecules. Endothelial dysfunction (ED) is recognized as a failure of endothelial repair mechanisms. It is also an early preclinical marker of atherosclerosis and is commonly found in RA patients. RA is now established as an independent cardiovascular risk factor, while mechanistic determinants of ED in RA are still poorly understood. An expanding body of study has shown that EC at a site of RA is both active participant and regulator of inflammatory process. Over the last decade, a role for endothelial dysfunction in RA associated with cardiovascular disease (CVD) has been hypothesized. At the same time, several maintenance drugs targeting this phenomenon have been tested, which has promising results. Assessment of endothelial function may be a useful tool to identify and monitor RA patients.

Serum leptin and serum leptin/serum leptin receptor ratio imbalance in obese rheumatoid arthritis patients positive for anti-cyclic citrullinated peptide antibodies

IntroductionLeptin has a prominent role in the development and maintenance of acute and chronic inflammatory states such as rheumatoid arthritis (RA) and obesity. Nevertheless, the association of serum leptin (sLep) and soluble leptin receptor (sLepR) in RA pathogenesis has not been clarified. The purpose of this study was to evaluate the association of sLep, sLepR and leptin production indexes such as sLep/fat mass ratio with clinical activity and biomarkers and anti-cyclic citrullinated peptide (anti-CCP) antibodies in RA compared with body mass index (BMI) matched control subjects.MethodsWe included 64 RA patients and 66 controls matched for age, gender and BMI. Subjects were evaluated for BMI, fat mass distribution, sLep, sLepR, sLep/fat mass ratio and sLepR/fat mass ratio. Patients were evaluated for clinical activity and anti-CCP antibodies.ResultsWe found two or three fold increased sLep levels, sLep/sLepR ratio and sLep/fat mass ratio in obese anti-CCP positive RA patients vs. controls. Partial correlations showed that anti-CCP antibodies were correlated with sLep/fat mass ratio (partial r = 0.347, P = 0.033) after adjustment for age, subcutaneous adipose tissue and fat mass.ConclusionsIn preobese and obese RA patients there is and increased production of sLep according to anti-CCP positivity. This phenomenon suggests there is an additive effect of chronic inflammation resulting from RA and obesity in which leptin favors the humoral response against citrullinated proteins. In summary, the data observed in our study suggests sLep could be a surrogate marker of chronicity and humoral immunity in RA in the presence of obesity.

Adaptive immunity in rheumatoid arthritis

To describe recent progress concerning rheumatoid arthritis (RA)-associated autoantibodies, in particular antibodies to citrullinated proteins antigens. An increasingly diverse and RA-associated repertoire of antibodies has been defined over the last few years. These antibodies are preferentially, but not exclusively, reactive with posttranslationally modified antigens. Citrullinated antigens are the most common targets, but also other modifications including homocitrullination (carbamylation) are recognized. These antibodies display varying degrees of cross-reactivity, and both broadly cross-reactive and monoreactive antibodies are present. Progress, described in this review, has been made both concerning mechanisms behind the generation of these antibodies and concerning their effector functions. Several different triggering mechanisms are involved in forming an antibody repertoire that evolves before the onset of clinical disease, and where antibodies with different specificities may interact directly or indirectly with target organs in causing different arthritis-associated symptoms. The increasing understanding of the role of adaptive and specific immunity in RA creates opportunities for a new generation of interventions.

PW01-040 – Definition of polymorphism C3435T MDR1 gene in JIA

Juvenile idiopathic arthritis (JIA) is one of the most common rheumatic disease in children. Brug of choice is methotrexate (MTX) - cytostatic drug from the group of antimetabolites, folic acid antagonists. According to various authors, about 70% of patients receiving therapy with MTX are in remission for the disease. In 1988, MTX was approved FDA (Food and Drug Administration, USA) for the treatment of rheumatoid arthritis. Currently, MTX is the main drug in the treatment of JIA. Preferred therapeutic recommendations on the number of MTX based on a randomized, double-blind, placebo-controlled study conducted in 1992. MDR1-gene product - the P-glycoprotein (P-gp), the protein acts as a trans-membrane pump, and affects the activity of many drugs. Polymorphism in the gene MDR1, may affect the pharmacokinetics of many drugs, including anticancer drugs. According to the authors of Jinwei Chen (2011) in adult patients with rheumatoid arthritis (RA) in the Chinese population C3435T MDR1 gene polymorphism may be associated with susceptibility to RA, but may influence the effectiveness of antirheumatic therapy of RA, and CC genotype may be associated with immune rheumatoid arthritis (RRA).