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Objective
To define the relationship of synovial B cells to clinical phenotypes at different stages of disease evolution and drug exposure in rheumatoid arthritis (RA).
Methods
Synovial biopsy specimens and demographic and clinical data were collected from 2 RA cohorts (n = 329), one of patients with untreated early RA (n = 165) and one of patient...
Contexts in source publication
Context 1
... total of 329 patients with RA were included in this study: 165 with untreated early RA (PEAC) and 164 with an inadequate response to TNFi (R4RA trial). Table 1 summarizes the patient characteristics. Both cohorts included patients with highly active RA (mean Disease Activity Score in 28 joints [DAS28] >5.1), with no differences in terms of disease activity (DAS28 and its components) and other clinical features, except for a higher prevalence of female patients, higher CRP levels, and higher proportion of ACPA positive patients in the cohort with established RA. ...Similar publications
Objectives
To determine the relationship between synovial versus skin transcriptional/histological profiles in patients with active psoriatic arthritis (PsA) and explore mechanistic links between diseased tissue pathology and clinical outcomes.
Methods
Twenty-seven active PsA patients were enrolled in an observational/open-label study and underwen...
Citations
... Like T cells, non-plasma B cells are numerous in synovial tissue from some patients with RA and largely absent in others. Patients with abundant synovial B cells are more likely to be seropositive and to have severe disease and erosions [11,24,26]. Synovial tissue that contains abundant B cells also tends to be rich in T cells and macrophages, so the presence of B cells in synovial tissue is a sign of highly inflamed tissue samples with marked leukocyte infiltration [11]. ...
Purpose of Review
Rheumatoid arthritis is one of the most common rheumatic and autoimmune diseases. While it can affect many different organ systems, RA primarily involves inflammation in the synovium, the tissue that lines joints. Patients with RA exhibit significant clinical heterogeneity in terms of presence or absence of autoantibodies, degree of permanent deformities, and most importantly, treatment response. These clinical characteristics point to heterogeneity in the cellular and molecular pathogenesis of RA, an area that several recent studies have begun to address.
Recent Findings
Single-cell RNA-sequencing initiatives and deeper focused studies have revealed several RA-associated cell populations in synovial tissues, including peripheral helper T cells, autoimmunity-associated B cells (ABCs), and NOTCH3⁺ sublining fibroblasts. Recent large transcriptional studies and translational clinical trials present frameworks to capture cellular and molecular heterogeneity in RA synovium. Technological developments, such as spatial transcriptomics and machine learning, promise to further elucidate the different types of RA synovitis and the biological mechanisms that characterize them, key elements of precision medicine to optimize patient care and outcomes in RA.
Summary
This review recaps the findings of those recent studies and puts our current knowledge and future challenges into scientific and clinical perspective.
... Rheumatoid arthritis (RA) is characterized by synovitis, which occurs primarily through B-cell infiltration (1). In the synovial joints, B cells and B-cell effector mechanisms are thought to trigger local autoantibody production (2), osteoclast formation and activation (3,4), and immune complexmediated inflammatory responses (5). ...
... CD20-positive cells, which reflect B cells, and CD138-positive cells, which reflect plasma cells, are found in the synovial membrane. T lymphocytes diffusely infiltrate around the follicles, and there are more CD 4-than CD8-positive cells (1,11). ...
A 58-year-old woman with rheumatoid arthritis was diagnosed with methotrexate-associated Hodgkin lymphoma. After receiving several chemotherapy regimens, she started nivolumab treatment. Two weeks later, she was hospitalized with worsening finger, wrist, and elbow joint pain. A synovial biopsy of the wrist joint showed villous synovial proliferation and linear infiltration of CD68-/CD3-positive T cells (with more CD8 than CD4 T cells) but no CD20-positive B cells or CD138-positive macrophages. These findings corresponded to synovitis associated with immune-related adverse events, which are induced mainly by T cells and are different from typical RA, in which B cells play a central role.
... Arthritis Research & Therapy (2023) 25:119 Background Clinical research on synovial tissue analysis in patients with chronic arthritis has increased in recent years. Interest is mainly focused on studying the early stages of the disease, not so much as a diagnostic tool [1], but on understanding pathogenic mechanisms and obtaining additional markers helpful for guiding therapeutic strategies [2][3][4][5][6][7]. ...
... Procedural feasibility was defined as the retrieval of histologically assessable tissue. Each biopsy was evaluated on H&E slides at a single cutting level to identify the fragments characterized by intact synovial tissue (IST, defined microscopically by the presence of characteristic vessels and stroma in the absence of artefactual changes) [5]. Biopsies were defined as gradable if containing a visible lining layer and a number of fragments displaying IST ≥ 4 [8]. ...
Background
A proof-of-concept study to evaluate the feasibility and safety of minimally invasive ultrasound (US)-guided synovial biopsy of the radiocarpal (RC) joint using the anatomical snuffbox as an access route.
Methods
Twenty consecutive patients with active chronic arthritis of the wrist underwent minimally invasive US-guided synovial biopsy of the RC joint using the anatomical snuffbox as the access route. Samples were retrieved from 3 predetermined biopsy target sites of the RC synovia (proximal, vault, and distal site), aiming for a minimum of 12 samples. The procedure’s feasibility was evaluated based on the number and histological quality of retrieved tissue fragments tested on pre-defined histometric parameters. The safety and tolerability of the procedure were assessed through 1-week and 1-month follow-up clinical evaluations.
Results
A median number of 17 fragments (≥ 1 mm diameter size at macroscopic evaluation) per procedure was processed for histopathology (range 9–24) and dedicated to the study. At the histopathologic evaluation, a gradable tissue (visible lining layer and ≥ 4 fragments with IST) was recognized in 19/20 biopsies (95%), and all pre-defined histometric parameters were judged applicable and successfully measured in 19/19 gradable biopsies. All three biopsy target sites showed sampling accessibility. The entire procedure was generally well tolerated. At the 1-month follow-up, no patients showed infectious complications.
Conclusions
The access route through the anatomical snuff box in US-guided synovial biopsies of the RC joint allows for a safe and targeted collection of adequate tissue samples. This modification of the traditional access route may allow easier, repeatable, and safer sampling of anatomically distinct areas of the wrist in the course of arthritis.
... pauci-immune, diffuse-myeloid, and lympho-myeloid [37]. Among these, lympho-myeloid synovium harbours a substantial number of infiltrating B and T cells and can be further divided into B cell-rich and B cell-poor based on the number of B cells and B cell-aggregates detected by immunohistochemistry [38]. It has been suggested that B cell-rich synovitis is associated with high disease activity [37]. ...
Memory B cells (MBCs) are an essential part of our immunological memory. They respond fast upon re-encountering pathogens and can differentiate into plasma cells that secrete protective antibodies. The focus of this review is on MBCs that lack, or express low levels of, CD21, hereafter referred to as CD21-/low. These cells are expanded in peripheral blood with age and during chronic inflammatory conditions such as viral infections, malaria, common variable immunodeficiency, and autoimmune diseases. CD21-/low MBCs have gained significant attention; they produce disease-specific antibodies/autoantibodies, and associate with key disease manifestations in some conditions. However, these cells can be divided into subsets based on classical B-cell and other markers, e.g., CD11c, FcRL4 and Tbet that, over the years, have become hallmarks to identify these cells. This has resulted in different names including age-associated, autoimmune-associated, atypical, tissue-like, tissue-resident, tissue-restricted, exhausted or simply CD21-/low B cells. It is however unclear whether the expanded ‘CD21-/low’ cells in one condition are equivalent to those in another, whether they express an identical gene signature and whether they have a similar function. Here, we will discuss these issues with the goal to understand whether the CD21-/low B cells are comparable in the different conditions.
... The adaptive immune response impacts RA pathogenesis via multiple pathways. The rich infiltration of the synovium by B cells is connected with higher disease activity and RF or ACPA seropositivity [35]. The latter directly contributes to the development of RA, as the autoantibodies could appear in serum even 10 years before the diagnosis of the disease, presumably preceding the appearance of inflammation. ...
Introduction
Rheumatoid arthritis (RA) is a chronic autoimmune disease that, even despite currently available treatment, seriously reduces the quality of life. The current speed of development of therapeutic agents against RA is not satisfactory. Moreover, many promising substances in the early stages of research do not reach the final phases of clinical trials. Models on which initial experiments are conducted do not fully reflect human pathogenesis. Overcoming this oversimplification might be a crucial step to accelerate studies on RA treatment.
Areas covered
The current approaches to produce novel models or to improve currently available models for the development of RA drugs have been discussed. Advantages and drawbacks of two- and three-dimensional cell cultures and animal models have been described based on recently published results of the most advanced studies. Moreover, approaches such as tissue engineering or organ-on-a-chip have been reviewed.
Expert opinion
The cell cultures and animal models used to date appear to be of limited value due to the complexity of the processes involved in RA. Current models in RA research should take into account the heterogeneity of patients in terms of disease subtypes, course, and activity. Several advanced models and tools using human cells and tissues have been developed, including three-dimensional tissues, liquid bioreactors, and more complex joint-on-a-chip devices. Human-based cell and tissue models and high-throughput readouts (omics), which have been supported by epidemiological studies, provide the basis for changing the direction of RA research. This may increase knowledge of the molecular mechanisms leading to disease development, to help identify new biomarkers for early detection, and to develop preventive strategies and more effective treatments.
... Even considering misdiagnosis, laboratory pitfalls and the expanding landscape of new autoantibodies, yet there clearly are individuals who are phenotypically indistinguishable from seropositive rheumatoid arthritis but lack detectable autoimmune responses. Despite the scarcity of specific studies, the genetic, environmental, and immunopathological background of true seronegative rheumatoid arthritis might at least in part diverge from that of autoantibody-positive disease [166], with predominance of macrophagic rather than lymphocytic pathways also at the primary site of inflammation, that is the synovial membrane [167,168]. In these patients, diagnosis and disease monitoring are purely on a clinical basis, with consequent delays in treatment institution and unfavorable outcomes [169]. ...
Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.
... Synovial B-cell infiltr the other hand, is a highly variable occurrence that is found in up to 40% of patien ing from complete absence to dense distribution within organized infiltrates [17 recent study discovered a considerable increase in B-cell synovitis in patients w stage treatment-resistant RA. As a result, it is being investigated as a possible s prognostic and predictive biomarkers in RA [175]. Furthermore, autoantibodies the synovium rather than in the peripheral blood and are class-switched during gression of RA, implying that the local synovial environment plays an importan the creation and maturation of autoantibody-producing B cells [176,177]. ...
... A recent study discovered a considerable increase in B-cell synovitis in patients with end-stage treatment-resistant RA. As a result, it is being investigated as a possible source of prognostic and predictive biomarkers in RA [175]. Furthermore, autoantibodies form in the synovium rather than in the peripheral blood and are class-switched during the progression of RA, implying that the local synovial environment plays an important role in the creation and maturation of autoantibody-producing B cells [176,177]. ...
Rheumatoid arthritis (RA) is an inflammatory disease that begins with a loss of tolerance to modified self-antigens and immune system abnormalities, eventually leading to synovitis and bone and cartilage degradation. Reactive oxygen species (ROS) are commonly used as destructive or modifying agents of cellular components or they act as signaling molecules in the immune system. During the development of RA, a hypoxic and inflammatory situation in the synovium maintains ROS generation, which can be sustained by increased DNA damage and malfunctioning mitochondria in a feedback loop. Oxidative stress caused by abundant ROS production has also been shown to be associated with synovitis in RA. The goal of this review is to examine the functions of ROS and related molecular mechanisms in diverse cells in the synovial microenvironment of RA. The strategies relying on regulating ROS to treat RA are also reviewed.
... The use of administrative data has well-known limitations but it also some advantages, including the possibility of analyzing large, unselected cohorts of patients treated according to the current clinical practice [36]. We acknowledge the fact that patients' administration of bDMARDS may have been biased according to local clinical practice, however, the drug prescriptions were in line with current and past guidelines [3,[17][18][19][20][21], taking in consideration that reliable biomarkers for drug allocation to patients are still lacking [37,38]. The results of these kinds of studies can thus complement those coming from registry and clinical trials. ...
Biological disease-modifying anti-rheumatic drugs (bDMARDs) are widely used for the management of rheumatoid arthritis, although their benefits are counterweight by an increased risk of infections. In the present study, we used administrative data to compare the risk of severe infections among different classes of bDMARDs. A retrospective cohort study was conducted using Administrative Health Databases of the Piedmont Region, Italy. Relevant data were obtained from: (1) the inhabitants registry, (2) hospital discharge records, and (3) the co-payment exemption registry and (4) drug claims registry. Fine and Gray competing risk models were fitted to evaluate the association between the use of different types of bDMARDs and occurrence of severe infection accounting for treatment interruption as competing risk. A total of 1780 new users of bDMARDs were identified. Among them, 50 hospitalizations for infection occurred during the study period. The use of Tocilizumab was associated with an increased risk of infection, compared to tumor necrosis factor (TNF) inhibitor drugs (sub-distribution hazard ratios-sHR: 2.510; 95% CI: 1.279-4.926), whereas no difference in the risk of severe infection was found for abatacept (sHR: 0.584; 95% CI: 0.234-1.457). bDMARDs treatment is generally safe in clinical practice with slight but important differences among classes. The increased risk of infection associated with tocilizumab use should be taken into account when balancing the risk and benefits of starting a treatment with this drug.
... Visualization of antibody binding was achieved by 30-min incubation with Dako EnVisionTM+ before completion by the addition of 3,3′-diaminobenzidine (DAB) + substrate chromogen for 10 s, followed by counterstaining with hematoxylin. Following IHC staining, sections underwent semiquantitative scoring (0-4), by a minimum of two assessors, to determine levels of CD20 + and CD79a + B cells, CD3 + T cells, CD138 + plasma cells and CD68 + lining (L) and sublining (SL) macrophages, adapted from a previously described score 43 and recently validated for CD20 44 . Hematoxylin-and-eosin-stained slides also underwent evaluation to determine the level of synovitis according to the Krenn synovitis score (0-9) 45 . ...
Patients with rheumatoid arthritis (RA) receive highly targeted biologic therapies without previous knowledge of target expression levels in the diseased tissue. Approximately 40% of patients do not respond to individual biologic therapies and 5–20% are refractory to all. In a biopsy-based, precision-medicine, randomized clinical trial in RA (R4RA; n = 164), patients with low/absent synovial B cell molecular signature had a lower response to rituximab (anti-CD20 monoclonal antibody) compared with that to tocilizumab (anti-IL6R monoclonal antibody) although the exact mechanisms of response/nonresponse remain to be established. Here, in-depth histological/molecular analyses of R4RA synovial biopsies identify humoral immune response gene signatures associated with response to rituximab and tocilizumab, and a stromal/fibroblast signature in patients refractory to all medications. Post-treatment changes in synovial gene expression and cell infiltration highlighted divergent effects of rituximab and tocilizumab relating to differing response/nonresponse mechanisms. Using ten-by-tenfold nested cross-validation, we developed machine learning algorithms predictive of response to rituximab (area under the curve (AUC) = 0.74), tocilizumab (AUC = 0.68) and, notably, multidrug resistance (AUC = 0.69). This study supports the notion that disease endotypes, driven by diverse molecular pathology pathways in the diseased tissue, determine diverse clinical and treatment–response phenotypes. It also highlights the importance of integration of molecular pathology signatures into clinical algorithms to optimize the future use of existing medications and inform the development of new drugs for refractory patients. Biomarker analysis of the phase 4 R4RA trial identifies pretreatment synovial biopsy features selectively associated with response to rituximab or tocilizumab, and leads to the development of models that might predict treatment benefit in patients with rheumatoid arthritis
... Thresholding was also used to segment lymphocyte nuclei and quantify synovial thickness on H&E-stained tissue sections, which correlated with clinical scores with reasonable success in synovial biopsies from patients with rheumatoid arthritis, osteoarthritis, and psoriatic arthritis [61]. Using thresholding techniques on stained tissue is still a common approach used in both clinical and preclinical settings [74] and can be a reliable measurement of tissue features, but it is highly sensitive to staining variation or other batch effects. In a similar approach, a classifier trained to segment nuclear and cytoplasmic/extracellular matrix (ECM) area (naïve Bayes model implemented in Visiopharm [75]) was used to segment these areas in H&E-stained tissues from a murine model of inflammatory arthritis, which corresponded to histopathology scores [62,63]. ...
Histopathology is widely used to analyze clinical biopsy specimens and tissues from pre-clinical models of a variety of musculoskeletal conditions. Histological assessment relies on scoring systems that require expertise, time, and resources, which can lead to an analysis bottleneck. Recent advancements in digital imaging and image processing provide an opportunity to automate histological analyses by implementing advanced statistical models such as machine learning and deep learning, which would greatly benefit the musculoskeletal field. This review provides a high-level overview of machine learning applications, a general pipeline of tissue collection to model selection, and highlights the development of image analysis methods, including some machine learning applications, to solve musculoskeletal problems. We discuss the optimization steps for tissue processing, sectioning, staining, and imaging that are critical for the successful generalizability of an automated image analysis model. We also commenting on the considerations that should be taken into account during model selection and the considerable advances in the field of computer vision outside of histopathology, which can be leveraged for image analysis. Finally, we provide a historic perspective of the previously used histopathological image analysis applications for musculoskeletal diseases, and we contrast it with the advantages of implementing state-of-the-art computational pathology approaches. While some deep learning approaches have been used, there is a significant opportunity to expand the use of such approaches to solve musculoskeletal problems.
