Use of ultrasound-guided small joint biopsy to evaluate the histopathologic response to rheumatoid arthritis therapy: recommendations for application to clinical trials

The access route through the anatomical snuffbox in ultrasound-guided synovial biopsy of the wrist allows for a safe and effective collection of tissue samples in inflammatory arthritis

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.

Best practices for ultrasound-guided synovial biopsy in the United States

The target organ in many forms of inflammatory arthritis is the synovium. However, synovial tissue has historically been perceived as either difficult to obtain or of little practical value. Ultrasound-guided synovial biopsy [UGSB] is a safe and well-tolerated bedside procedure that is established in Europe and rapidly growing in popularity in the United States. The technique can be mastered by rheumatologists who are already experienced in ultrasound-guided procedures such as joint aspirations. The USGB procedure allows the proceduralist to access small, medium, and large joints and is inexpensive and less invasive compared to surgical alternatives. The relative ease of obtaining this tissue, along with recent research suggesting that synovium may have more clinical and investigational utility than previously thought, has led clinicians and researchers to a new appreciation of the role of synovial biopsy in both the clinical and research setting. In this manuscript, the authors present recommendations on best practices for ultrasound-guided synovial biopsy in the United States, based on our initial training with well-established experts overseas and our own subsequent collective experience in performing numerous synovial biopsies in the United States over the past 7 years for both clinical and research indications. We envision a future where UGSB is more frequently incorporated in the standard diagnostic workup of arthritis and drives novel research initiatives.

Contribution of pathogenic T helper 1 and 17 cells to bursitis and tenosynovitis in polymyalgia rheumatica

Background

Although polymyalgia rheumatica (PMR) is a very common rheumatic inflammatory disease, current insight into the pathobiology of PMR is limited and largely based on studies in blood. We investigated T helper 1 (T_H1) and T helper 17 (T_H17) cell responses in blood, synovial fluid and bursa tissue of patients with PMR.

Materials and methods

Blood samples were collected from 18 patients with new-onset PMR and 32 healthy controls. Synovial fluid was aspirated from the inflamed shoulder bursae or biceps tendon sheath of 13 patients. Ultrasound-guided biopsies of the subacromial-subdeltoid (SASD) bursa were obtained from 11 patients. T cells were examined by flow cytometry, immunohistochemistry and immunofluorescence staining.

Results

Besides an increase of T_H17 (CD4⁺IL-17⁺IFN-γ^-) cells and T cytotoxic 17 (T_C17; CD8⁺IL-17⁺IFN-γ^-) cells, no other major changes were noted in the circulating T cell compartment of patients with PMR. Absolute numbers of CD4⁺ and CD8⁺ T cells were similar in blood and synovial fluid of patients with PMR. Synovial fluid T cells showed an effector-memory (CD45RO⁺CCR7^-) phenotype. Percentages of T_H1 (CD4⁺IFN-γ⁺IL-17^-) cells and T_H1/T_H17 (CD4⁺IFN-γ⁺IL-17⁺) cells, but not T_H17 or T_C17 cells, were increased in the synovial fluid. Bursa tissue biopsies contained a small number of T cells, which were mostly CD8 negative. The majority of bursa tissue T cells produced IFN-γ but not IL-17. For comparison, B cells were scarcely detected in the bursa tissue.

Conclusion

Although the circulating T_H17 cell pool is expanded in patients with PMR, our findings indicate that T_H1 cells are involved in the inflammation of bursae and tendon sheaths in this condition. Our study points towards the T_H1 cell pathway as a potential target for therapy in PMR.

Promising role of polymeric nanoparticles in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory illness caused by an autoimmune disorder of synovial membrane resulting in synovial membrane dysfunction. The available treatment particularly focuses on inhibiting macrophage proliferation and reducing the generation of pro-inflammatory cytokines. However, therapeutic success of current treatment options at targeted site is limited; therefore, development of promising therapeutic strategy is the need of time that may provide better targeted delivery of drug with added safety. In development of precision medicine to manage RA, nanotechnology is a viable option to be considered. Recent research using nanoparticles for the treatment of RA, particularly polymeric nanoparticles, has been discussed in this article. Using polymeric nanoparticles as a therapeutic method has shown considerable promise of enhancing treatment success over standard medications used in routine. It is exclusively evident that the viability of using nanoparticles is mainly owed due to their biocompatibility, chemical stability, controlled drug release, and selective drug delivery to inflamed tissues in RA model animals. The current analysis focuses on the critical design characteristics of RA-targeted nanotechnology-based strategies in quest of better therapeutic strategies for RA, and to identify leading polymer as the most effective medications in RA therapy.

EULAR points to consider for minimal reporting requirements in synovial tissue research in rheumatology

BACKGROUND

Synovial tissue research has become widely developed in several rheumatology centres, however, large discrepancies exist in the way synovial tissue is handled and, more specifically, how data pertaining to biopsy procedure, quality check and experimental results are reported in the literature. This heterogeneity hampers the progress of research in this rapidly expanding field. In that context, under the umbrella of European Alliance of Associations for Rheumatology, we aimed at proposing points to consider (PtC) for minimal reporting requirements in synovial tissue research.

METHODS

Twenty-five members from 10 countries across Europe and USA met virtually to define the key areas needing evaluation and formulating the research questions to inform a systematic literature review (SLR). The results were presented during a second virtual meeting where PtC were formulated and agreed.

RESULTS

Study design, biopsy procedures, tissue handling, tissue quality control and tissue outcomes (imaging, DNA/RNA analysis and disaggregation) were identified as important aspects for the quality of synovial tissue research. The SLR interrogated four databases, retrieved 7654 abstracts and included 26 manuscripts. Three OPs and nine PtC were formulated covering the following areas: description of biopsy procedure, overarching clinical design, patient characteristics, tissue handling and processing, quality control, histopathology, transcriptomic analyses and single-cell technologies.

CONCLUSIONS

These PtC provide guidance on how research involving synovial tissue should be reported to ensure a better evaluation of results by readers, reviewers and the broader scientific community. We anticipate that these PtC will enable the field to progress in a robust and transparent manner over the coming years.

Impact of synovial biopsy procedures and disease-specific aspects on synovial tissue outcome: a systematic literature review informing the EULAR points to consider for the minimal reporting requirements in synovial tissue research in rheumatology

BACKGROUND

The aim of this work was to summarise the literature evaluating the impact of biopsy procedures, tissue handling, tissue quality and disease-specific aspects including joint biopsied and disease stage, on synovial tissue outcome.

METHODS

Two reviewers independently identified eligible studies according to the Patients, Intervention, Comparator and Outcome framework obtained for five research questions formulated during the first EULAR task force meeting to produce points to consider (PtC) for minimal reporting requirements in synovial tissue studies. The databases explored were Medline, Embase, CENTRAL and Cinhal. The risk of bias of each study was evaluated using an adapted version of the Joanna Briggs Institute checklist for analytical cross-sectional studies.

RESULTS

Of the 7654 records yielded, 75 full texts were assessed, leading to the inclusion of 26 manuscripts in the systematic literature review (SLR). Two papers assessed the impact of biopsy procedures on the quality and quantity of tissue retrieved alongside patient tolerability; six papers focused on synovial tissue variability. Four papers studied the impact of sample handling or randomisation and 14 assessed the impact of disease stage and state, namely early or established active rheumatoid arthritis and remission on histopathological and transcriptomic results.

CONCLUSIONS

This SLR informs the EULAR PtC for minimal reporting requirements in synovial tissue research in rheumatology. Characteristics related to the study design, population, sample handling, randomisation and analysis can affect the final synovial tissue outcome in the studies reviewed. Thus, accurate reporting of these factors is required in order to ensure the scientific validity of manuscripts describing synovial tissue outcomes.

Cellular and molecular diversity in Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a chronic systemic autoimmune disease. RA mainly affects synovial joints, with inflammation of the synovial membrane (synovitis), characterised by neo-angiogenesis, hyperplasia of lining layer, and immune cell infiltration that drive local inflammation and, if untreated, can lead to joint destruction and disability. In parallel to the well-known clinical heterogeneity, the underlying synovitis can also be significantly heterogeneous, both at cellular and molecular level, which can at least in part explain why despite the availability of highly effective treatment options, a large proportion of patients are resistant to some individual treatments. The assimilation of recent high-throughput data from analysis at the single-cell level with rigorous and high-quality clinical outcomes obtained from large randomised clinical trials support the definition of disease and treatment response endotypes. Looking ahead, the integration of histological and molecular signatures from the diseased tissue into clinical algorithms may help decision making in the management of patients with Rheumatoid Arthritis in clinical practice.

Ultrasound-Guided Synovial Biopsy: A Review

Ultrasound-guided synovial biopsy is a safe, well-tolerated, and effective method to collect good-quality synovial tissue from all types of joints for clinical and research purposes. Although synovial biopsy cannot be used to distinguish between types of inflammatory rheumatic disease, analysis of synovial tissue has led to remarkable advances in the understanding of the pathobiology of rheumatoid arthritis and other inflammatory rheumatic diseases. Synovitis is the hallmark of these diseases; hence, accessing the core of the pathological process, synovial tissue, provides an opportunity to gather information with potential diagnostic and prognostic utility.

Efficacy, Safety, and Sample Quality of Ultrasound-Guided Synovial Needle Biopsy in Clinical Practice and Research: A Prospective Observational Study

OBJECTIVE

To study the efficacy, tolerability, safety, and sampling variation of ultrasound (US)-guided synovial biopsies performed in clinical practice and research.

METHODS

We included all patients who had a US-guided synovial needle biopsy from November 2013 to January 2018. Patients were evaluated for procedure safety and tolerability. Usefulness of synovial biopsy was considered based on contribution for achieving the proposed aims. We analyzed samples for presence and quality of synovial tissue, synovitis score/grade, and pathotype. Variation across patients, samples, section levels, and sampling order was assessed.

RESULTS

A total of 64 US-guided synovial biopsies were performed (n = 52 in clinical practice, n = 12 in research). Patient tolerability (70% no/mild discomfort) was remarkably high. There was no significant aggravation of symptoms or US synovitis in the biopsied joint. Procedures were overall safe, with few minor, 2 moderate, and no major adverse events. Usefulness of US-guided synovial biopsies was high, both in clinical practice (37% direct diagnostic impact, 100% positive/95% negative predictive values for infection) and in research (92% success). Synovial tissue was retrieved in 88% of biopsies, with a median of 75% gradable samples. There was significant variation in sample quality and synovitis features across patients and samples, but not between different section levels. Samples collected later in the procedure had a lower frequency of synovial tissue and were poorly concordant in pathotype with those collected earlier.

CONCLUSION

US-guided synovial needle biopsy is an effective, safe, and well-tolerated means to collect good quality synovial tissue for clinical and research purposes. Samples collected for different aims should be retrieved in parallel, rather than sequentially.

Transforming clinical trials in rheumatology: towards patient-centric precision medicine

Despite the success of targeted therapies in the treatment of inflammatory arthritides, the lack of predictive biomarkers drives a 'trial and error' approach to treatment allocation, leading to variable and/or unsatisfactory responses. In-depth characterization of the synovial tissue in rheumatoid arthritis, as well as psoriatic arthritis and spondyloarthritis, is bringing new insights into the diverse cellular and molecular features of these diseases and their potential links with different clinical and treatment-response phenotypes. Such progress raises the tantalizing prospect of improving response rates by matching the use of specific agents to the cognate target pathways that might drive particular disease subtypes in specific patient groups. Innovative patient-centric, molecular pathology-driven clinical trial approaches are needed to achieve this goal. Whilst progress is clearly being made, it is important to emphasize that this field is still in its infancy and there are a number of potential barriers to realizing the premise of patient-centric clinical trials.

A Pauci-Immune Synovial Pathotype Predicts Inadequate Response to TNFα-Blockade in Rheumatoid Arthritis Patients

Objectives: To assess whether the histopathological features of the synovium before starting treatment with the TNFi certolizumab-pegol could predict clinical outcome and examine the modulation of histopathology by treatment. Methods: Thirty-seven RA patients fulfilling UK NICE guidelines for biologic therapy were enrolled at Barts Health NHS trust and underwent synovial sampling of an actively inflamed joint using ultrasound-guided needle biopsy before commencing certolizumab-pegol and after 12-weeks. At 12-weeks, patients were categorized as responders if they had a DAS28 fall >1.2. A minimum of 6 samples was collected for histological analysis. Based on H&E and immunohistochemistry (IHC) staining for CD3 (T cells), CD20 (B cells), CD138 (plasma cells), and CD68 (macrophages) patients were categorized into three distinct synovial pathotypes (lympho-myeloid, diffuse-myeloid, and pauci-immune). Results: At baseline, as per inclusion criteria, DAS28 mean was 6.4 ± 0.9. 94.6% of the synovial tissue was retrieved from the wrist or a metacarpophalangeal joint. Histological pathotypes were distributed as follows: 58% lympho-myeloid, 19.4% diffuse-myeloid, and 22.6% pauci-immune. Patients with a pauci-immune pathotype had lower levels of CRP but higher VAS fatigue compared to lympho- and diffuse-myeloid. Based on DAS28 fall >1.2, 67.6% of patients were deemed as responders and 32.4% as non-responders. However, by categorizing patients according to the baseline synovial pathotype, we demonstrated that a significantly higher number of patients with a lympho-myeloid and diffuse-myeloid pathotype in comparison with pauci-immune pathotype [83.3% (15/18), 83.3 % (5/6) vs. 28.6% (2/7), p = 0.022) achieved clinical response to certolizumab-pegol. Furthermore, we observed a significantly higher level of post-treatment tender joint count and VAS scores for pain, fatigue and global health in pauci-immune in comparison with lympho- and diffuse-myeloid patients but no differences in the number of swollen joints, ESR and CRP. Finally, we confirmed a significant fall in the number of CD68+ sublining macrophages post-treatment in responders and a correlation between the reduction in the CD20+ B-cells score and the improvement in the DAS28 at 12-weeks. Conclusions: The analysis of the synovial histopathology may be a helpful tool to identify among clinically indistinguishable patients those with lower probability of response to TNFα-blockade.

B Cell Synovitis and Clinical Phenotypes in Rheumatoid Arthritis: Relationship to Disease Stages and Drug Exposure

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 patients with established RA with an inadequate response to tumor necrosis factor inhibitors (TNFi-IR; n = 164). Synovial tissue was subjected to hematoxylin and eosin and immunohistochemical staining and semiquantitative assessment for the degree of synovitis (on a scale of 0-9) and of CD20+ B cell infiltrate (on a scale of 0-4). B cell scores were validated by digital image analysis and B cell lineage-specific transcript analysis (RNA-Seq) in the early RA (n = 91) and TNFi-IR (n = 127) cohorts. Semiquantitative CD20 scores were used to classify patients as B cell rich (≥2) or B cell poor (<2).

RESULTS

Semiquantitative B cell scores correlated with digital image analysis quantitative measurements and B cell lineage-specific transcripts. B cell-rich synovitis was present in 35% of patients in the early RA cohort and 47.7% of patients in the TNFi-IR cohort (P = 0.025). B cell-rich patients showed higher levels of disease activity and seropositivity for rheumatoid factor and anti-citrullinated protein antibody in early RA but not in established RA, while significantly higher histologic synovitis scores in B cell-rich patients were demonstrated in both cohorts.

CONCLUSION

We describe a robust semiquantitative histologic B cell score that closely replicates the quantification of B cells by digital or molecular analyses. Our findings indicate an ongoing B cell-rich synovitis, which does not seem to be captured by standard clinimetric assessment, in a larger proportion of patients with established RA than early RA.

Multiparameter Analysis Identifies Heterogeneity in Knee Osteoarthritis Synovial Responses

OBJECTIVE

Synovial membrane inflammation is common in osteoarthritis (OA) and increases cartilage injury. However, synovial fluid and histology studies suggest that OA inflammatory responses are not homogeneous. Greater understanding of these responses may provide new insights into OA disease mechanisms. We undertook this study to develop a novel multiparameter approach to phenotype synovial responses in knee OA.

METHODS

Cell composition and soluble protein production were measured by flow cytometry and multiplex enzyme-linked immunosorbent assay in synovium collected from OA patients undergoing knee replacement surgery (n = 35).

RESULTS

Testing disaggregation conditions showed that aggressive digestion improved synovial cell yield and mesenchymal staining by flow cytometry, but it negatively impacted CD4+ T cell and CD56+ natural killer cell staining. Less aggressive digestion preserved these markers and showed highly variable T cell infiltration (range 0-43%; n = 32). Correlation analysis identified mesenchymal subpopulations associated with different nonmesenchymal populations, including macrophages and T cells (CD45+CD11b+HLA-DR+ myeloid cells with PDPN+CD73+CD90-CD34- mesenchymal cells [r = 0.65, P < 0.0001]; and CD45+CD3+ T cells with PDPN+CD73+CD90+CD34+ mesenchymal cells [r = 0.50, P = 0.003]). Interleukin-6 (IL-6) measured by flow cytometry strongly correlated with IL-6 released by ex vivo culture of synovial tissue (r = 0.59, P = 0.0012) and was highest in mesenchymal cells coexpressing CD90 and CD34. IL-6, IL-8, complement factor D, and IL-10 release correlated positively with tissue cellularity (P = 0.0042, P = 0.018, P = 0.0012, and P = 0.038, respectively). Additionally, increased CD8+ T cell numbers correlated with retinol binding protein 4 (P = 0.033). Finally, combining flow cytometry and multiplex data identified patient clusters with different types of inflammatory responses.

CONCLUSION

We used a novel approach to analyze OA synovium, identifying patient-specific inflammatory clusters. Our findings indicate that phenotyping synovial inflammation may provide new insights into OA patient heterogeneity and biomarker development.

Levels of CXCL13 and sICAM-1 correlate with disease activity score in patients with rheumatoid arthritis treated with tocilizumab

Background

Tocilizumab (TCZ), a humanized monoclonal antibody against the interleukin-6 receptor, has been proven to be a safe and effective treatment for rheumatoid arthritis (RA). Because RA is a heterogenous disease and patient response to treatments can vary, identifying characteristics that predict which patients are more likely to respond to TCZ is important for optimal patient care. Serum levels of C-X-C motif chemokine ligand 13 (CXCL13) and soluble intercellular adhesion molecule-1 (sICAM-1) have been associated with response to TCZ in patients with RA.

Objectives

To evaluate the association of CXCL13 and sICAM-1 with disease activity and response to TCZ in patients with early RA and those with inadequate response to disease-modifying antirheumatic drugs (DMARD-IR).

Methods

Baseline and week 24 serum CXCL13 and sICAM-1 levels were measured using available patient samples from the FUNCTION (early RA) and LITHE (DMARD-IR) trials. Correlations between CXCL13 and sICAM-1 levels and Disease Activity Score in 28 joints calculated with erythrocyte sedimentation rate (DAS28-ESR) at baseline and between change in CXCL13 and sICAM-1 and change in DAS28-ESR at week 24 were estimated. CXCL13 and sICAM-1 changes from baseline to week 24 were compared between treatment arms. The effects of TCZ treatment and baseline DAS28-ESR, CXCL13 and sICAM-1 levels on DAS28-ESR remission and 50% improvement per the American College of Rheumatology (ACR50) response at week 24 were determined.

Results

Overall, 458 patients from FUNCTION and 287 patients from LITHE were included. Correlation of baseline serum CXCL13 and sICAM-1 levels with DAS28-ESR was weak to moderate. CXCL13 and sICAM-1 levels decreased significantly at week 24 in TCZ-treated patients in both the early-RA and DMARD-IR populations. CXCL13 and sICAM-1 changes correlated moderately to weakly with DAS28-ESR changes at week 24 in both populations. The treatment regimen, but not baseline CXCL13 and sICAM-1 levels, had a significant effect on the likelihood of DAS28-ESR remission and ACR50 response.

Conclusions

Although CXCL13 and sICAM-1 are modestly associated with RA disease activity, they do not predict response to TCZ in all RA populations.

Six-month prospective trial in early and long-standing rheumatoid arthritis: evaluating disease activity in the wrist through sequential synovial histopathological analysis, RAMRIS magnetic resonance score and EULAR-OMERACT ultrasound score

Introduction

Standardised scoring systems for rheumatoid arthritis (RA) joint disease activity include Larsen score for radiographs, rheumatoid arthritis magnetic resonance imaging score (RAMRIS) for MRI and using the European League Against Rheumatisms-Outcome Measures in Rheumatology (EULAR-OMERACT) score for ultrasound (US) images. The aim of this prospective study was to investigate the relationship between histological synovitis and radiological synovitis, assessed by conventional X-ray, US and MRI of the wrist radiocarpal joint.

Methods

20 patients with treatment naive early RA (ERA) and 20 with long-standing RA (LRA) were enrolled in a 6-month prospective study. Patients with RA underwent US-guided synovial biopsy, X-ray and US of the wrist at enrolment and 6 months. MRI at baseline and also at 6 months for the ERA group, and scored with the RAMRIS system. X-ray was scored by Larsen score and US by the EULAR-OMERACT system. Synovial biopsy inflammation was determined by the Krenn score.

Results

In the ERA group at baseline, Krenn score was correlated strongly with both US combined score (r = 0.77 p < 0.001) and MRI synovitis score (r = 0.85 p < 0.001), while uncorrelated at 6 months. In the LRA group at baseline, these scores correlated strongly (r = 0.83, p < 0.001) to moderately (r = 0.61, p = 0.002), and persisted at 6 months for US score (r = 0.81 p < 0.001). For all patients with RA, change in Krenn score between baseline and 6 months was correlated with both change in US combined score (r = 0.65, p < 0.001) and change in MRI synovitis score (r = 0.50, p = 0.03).

Conclusion

The MRI RAMRIS synovitis score and EULAR-OMERACT US scoring system are sensitive measures of histological synovitis in LRA and ERA. After 6 months, this correlation persists in the established RA group, but not in the ERA group. Overall, decreases in MRI/US synovitis are associated with reductions in histological synovitis. The study validates the use of MRI RAMRIS and EULAR-OMERACT US scores as surrogate markers of histological synovitis in established RA and early untreated RA.

Clinical Applications of Synovial Biopsy

The synovial tissue is a primary target of multiple diseases characterized by different pathogenic mechanisms, including infective, deposition, neoplastic, and chronic immune-inflammatory pathologies. Synovial biopsy can have a relevant role in differential diagnosis of specific conditions in clinical practice, although its exploitation remains relatively limited. In particular, no validated synovial-tissue-derived biomarkers are currently available in the clinic to aid in the diagnosis and management in most frequent forms of chronic inflammatory arthropathies, namely rheumatoid arthritis (RA) and the spondyloarthritides (SpA). In this brief review, we will discuss the current spectrum of clinical applications of synovial biopsy in routine rheumatologic care and will provide an analysis of the perspectives for its potential exploitation in patients with chronic inflammatory arthritides.

Differential synovial tissue biomarkers among psoriatic arthritis and rheumatoid factor/anti-citrulline antibody-negative rheumatoid arthritis

Background

Differential diagnosis among psoriatic arthritis (PsA) and seronegative rheumatoid arthritis (Ab^neg RA) can be challenging particularly in the clinical setting of peripheral phenotype and autoantibodies seronegativity. The aim of the study was to identify synovial tissue (ST) biomarkers differentially expressed in PsA and Ab^neg RA and test their predictive value of therapeutic response.

Methods

Thirty-four PsA patients [12 DMARD naive and 22 non-responder to methotrexate (MTX-IR)] with peripheral joint involvement and 55 Ab^neg RA (27 DMARD naive and 28 MTX-IR) underwent US-guided ST biopsy and immunohistochemistry (IHC) for CD68⁺, CD3⁺, CD20⁺, CD21⁺, CD117⁺, and CD138⁺ cells. After study entry, each DMARD-naive patient started MTX therapy and was followed in an outpatient setting for at least 6 months to define the achievement of Minimal Disease Activity (PsA) and DAS remission (Ab^neg RA) status respectively. Each IR-MTX patient was treated according to EULAR recommendations.

Results

At study entry, IHC analysis revealed that PsA patients had comparable levels of lining and sublining CD68⁺ and sublining CD21⁺, CD20⁺, and CD3⁺ cells than Ab^neg RA, despite the therapeutic regimen. Moreover, regardless of the therapeutic scheme, PsA patients showed higher IHC score of CD117⁺ cells (p = 0.0004 and p = 0.0005 for naive and MTX-IR patients respectively) compared to Ab^neg RA patients. Conversely, Ab^neg RA patients showed higher IHC score of CD138⁺ cells, irrespective to the therapeutic scheme (p = 0.04 and p = 0.002 for naive and MTX-IR patients respectively). Analyzing the response rate to the therapeutic scheme, naive PsA patients reaching MDA status at 6 months follow-up, showed, at the study entry, lower IHC score of CD3⁺ cells compared to PsA patients not reaching this outcome (p = 0.02); conversely, naive Ab^neg RA patients reaching DAS remission status at 6 months follow-up, showed, at the study entry, lower IHC score of sublining CD68⁺ cells compared to Ab^neg RA patients not reaching this outcome (p < 0.001).

Conclusions

CD117⁺ and CD138⁺ cells are differentially distributed among PsA and Ab^neg RA. Histological analysis of ST may help to solve the clinical overlap between the two diseases and provides prognostic data about the therapy success.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1898-7) contains supplementary material, which is available to authorized users.

Synovial Tissue Sampling in Rheumatological Practice-Past Developments and Future Perspectives

Synovial biopsies are performed in routine clinical care in order to refine diagnosis as well as within a research setting. Progress in the development of minimally invasive synovial sampling methods in the last century has accelerated and facilitated novel insights into disease pathogenesis. This review discusses the development of synovial biopsy techniques as well as examining the three currently most commonly used approaches: arthroscopic, blind needle biopsy and ultrasound guided approaches. It also highlights major research advances driven through synovial research and considers future developments.

Ultrasound-Guided Synovial Biopsies of Wrists, Metacarpophalangeal, Metatarsophalangeal, Interphalangeal Joints, and Tendon Sheaths

Ultrasound-guided synovial biopsy (UGSB) is a minimally-invasive procedure which allows quality synovial tissue retrieval. In this article, we will discuss overarching principles of the procedure performed in wrists, metacarpophalangeal (MCP), metatarsophalangeal (MTP), interphalangeal joints (IP), and tendon sheaths, including basic sonoanatomy, entry site and biopsy technique, as well as special considerations for each structure whenever relevant.

Significant association between joint ultrasonographic parameters and synovial inflammatory factors in rheumatoid arthritis

BACKGROUND

Ultrasonography (US) can directly demonstrate joint inflammation, including grayscale (GS) signs of synovial hypertrophy and power Doppler (PD) techniques to demonstrate increased blood flow and vascularization. Recently, echogenicity, especially hypoechoic synovium, has also been associated with local inflammatory activity. However, only a few studies have demonstrated correlation between histopathologic and immunopathologic evaluation and US findings. The aim of this study was to clarify whether joint US findings including synovial hypertrophy, vascularity, and echogenicity can accurately characterize synovial pathophysiology in patients with active rheumatoid arthritis (RA).

METHODS

A total of 44 patients with RA were included, both treated (n = 25) and untreated (n = 19) and scheduled for US examination of the knee joint with synovial fluid (SF) aspiration and two treated patients also underwent synovial biopsy. US images were quantitatively analyzed using grayscale assessment of synovial hypertrophy and PD for vascularity and echogenicity. Levels of nine SF cytokines and growth factors were also measured.

RESULTS

Both US synovial hypertrophy and PD vascularity significantly correlated with SF inflammatory cytokine levels such as IL-6, IL-8, IL-1β and IL-10 in untreated patients. Angiogenic factors, including vascular endothelial growth factor (VEGF), only correlated with PD vascularity. In the treated patients, the associations between synovial hypertrophy and any cytokines were diminished, although synovial vascularity and echogenicity correlated with IL-6 and VEGF (p < 0.05). Histopathologic analysis revealed that hypoechogenicity of the synovium correlated with marked infiltration of lymphocytes and hypervascularity.

CONCLUSIONS

We demonstrated the pathophysiological origins of US findings in the joint. The degree of US vascularity of the synovium correlated with local inflammatory cytokine levels and angiogenetic factors in patients with active RA. Synovial echogenicity, and not hypertrophy, correlated with inflammation, especially in treated patients with RA.

Standardisation of synovial biopsy analyses in rheumatic diseases: a consensus of the EULAR Synovitis and OMERACT Synovial Tissue Biopsy Groups

Background

The aim of this global collaboration was to develop a consensual set of items for the analysis of synovial biopsies in clinical practice and translational research through the EULAR Synovitis Study Group (ESSG) and OMERACT Synovial Tissue Biopsy Group.

Methods

Participants were consulted through a modified Delphi method. Three sequential rounds occurred over 12 months. Members were sent a written questionnaire containing items divided into two parts. Items were identified and formulated based on a scoping review. The first part of the questionnaire referred to synovial biopsies in clinical practice including five subsections, and the second part to translational research with six subsections. Every participant was asked to score each item on a 5-point Likert scale. Items with a median score above 3.5 and a ≥ 70% agreement were selected for the next round. The last round was conducted orally at EULAR in June 2017.

Results

Twenty-seven participants from 19 centers were contacted by email. Twenty participants from 17 centers answered. Response rates for next rounds were 100%. For the first part relating to clinical practice, 20/44 items (45.5%) were selected. For the second part relating to translational research, 18/43 items (41.9%) were selected for the final set.

Conclusions

We herein propose a consensual set of analysis items to be used for synovial biopsies conducted in clinical practice and translational research.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1762-1) contains supplementary material, which is available to authorized users.

Patient-reported outcomes and safety in patients undergoing synovial biopsy: comparison of ultrasound-guided needle biopsy, ultrasound-guided portal and forceps and arthroscopic-guided synovial biopsy techniques in five centres across Europe

Background

We present a European multicenter study, comparing safety data and patient-reported outcomes (PRO) from patients undergoing synovial biopsy using ultrasound-guided needle biopsy (US-NB), ultrasound-guided portal and forceps (US-P&F) or arthroscopic-guided (AG) procedures.

Objectives

To describe safety and PRO data on joint indices of pain, stiffness and swelling before and after biopsy, procedural discomfort, joint status compared with before biopsy and willingness to undergo a second biopsy for each technique and compare the three techniques. To evaluate the impact on PRO and safety data of corticosteroid therapy as part of the biopsy procedure and sequential biopsy procedures.

Methods

Data were collected on the day of biopsy and 7-14 days postprocedure. Joint pain, swelling and stiffness indices were recorded as 0-100  mm Visual Analogue Scale; qualitative outcome variables on five-point Likert scales. Groups were compared with linear regression, adjusting for disease activity, corticosteroid therapy and prebiopsy PRO value and accounting for repeated measurements.

Results

A total of 524 synovial biopsy procedures were documented (402 US-NB, 65 US-P&F and 57 AGSB). There were eight adverse events (1.5%) with no difference between biopsy methods (p=0.55). All PROs were improved 2  weeks postprocedure, and there were no differences in postbiopsy change in PROs between biopsy methods. Corticosteroid administration, whether intramuscular (n=62) or intra-articular (n=38), did not result in more adverse events (p=0.81) and was associated with reduction in postbiopsy swelling (p<0.01). Sequential biopsy procedures (n=103 patients) did not result in more adverse events (p=0.61) or worsening in PRO data.

Conclusion

Overall, our results do not suggest a significant difference in safety or patient tolerability between US-NB, US-P&F and AGSB sampling. Further, corticosteroid therapy as part of the biopsy procedure and sequential biopsies is safe and well tolerated in patients.

Role of chemokines in ectopic lymphoid structures formation in autoimmunity and cancer

Ectopic (or tertiary) lymphoid structures (ELS) are organized aggregates of lymphocytes resembling secondary lymphoid organs and developing in chronically inflamed nonlymphoid tissues during persistent infections, graft rejection, autoimmune conditions, and cancer. In this review, we will first depict the mechanisms regulating ELS generation, focusing on the role played by lymphoid chemokines. We will then characterize ELS forming in target organs during autoimmune conditions, here exemplified by rheumatoid arthritis, and cancer, highlighting the relevance of the tissue-specific factors. Finally, we will discuss the clinical significance of ELS and the therapeutic potential of their inhibition and/or enhancement depending on the disease considered.

Transcriptional Profiling of Synovial Macrophages Using Minimally Invasive Ultrasound-Guided Synovial Biopsies in Rheumatoid Arthritis

OBJECTIVE

Currently, there are no reliable biomarkers for predicting therapeutic response in patients with rheumatoid arthritis (RA). The synovium may unlock critical information for determining efficacy, since a reduction in the numbers of sublining synovial macrophages remains the most reproducible biomarker. Thus, a clinically actionable method for the collection of synovial tissue, which can be analyzed using high-throughput strategies, must become a reality. This study was undertaken to assess the feasibility of utilizing synovial biopsies as a precision medicine-based approach for patients with RA.

METHODS

Rheumatologists at 6 US academic sites were trained in minimally invasive ultrasound-guided synovial tissue biopsy. Biopsy specimens obtained from patients with RA and synovial tissue from patients with osteoarthritis (OA) were subjected to histologic analysis, fluorescence-activated cell sorting, and RNA sequencing (RNA-seq). An optimized protocol for digesting synovial tissue was developed to generate high-quality RNA-seq libraries from isolated macrophage populations. Associations were determined between macrophage transcriptional profiles and clinical parameters in RA patients.

RESULTS

Patients with RA reported minimal adverse effects in response to synovial biopsy. Comparable RNA quality was observed from synovial tissue and isolated macrophages between patients with RA and patients with OA. Whole tissue samples from patients with RA demonstrated a high degree of transcriptional heterogeneity. In contrast, the transcriptional profile of isolated RA synovial macrophages highlighted different subpopulations of patients and identified 6 novel transcriptional modules that were associated with disease activity and therapy.

CONCLUSION

Performance of synovial tissue biopsies by rheumatologists in the US is feasible and generates high-quality samples for research. Through the use of cutting-edge technologies to analyze synovial biopsy specimens in conjunction with corresponding clinical information, a precision medicine-based approach for patients with RA is attainable.

A Multicenter Retrospective Analysis Evaluating Performance of Synovial Biopsy Techniques in Patients With Inflammatory Arthritis: Arthroscopic Versus Ultrasound-Guided Versus Blind Needle Biopsy

OBJECTIVE

To evaluate whether the choice of synovial biopsy technique (arthroscopy, blind needle [BN] biopsy, ultrasound [US]-guided portal and forceps [P&F], or US-guided needle biopsy [NB]) translates to significant variation in synovial tissue quality and quantity, with the aim of informing recommendations for the choice of synovial sampling technique within clinical trials.

METHODS

In total, 159 procedures from 5 academic rheumatology centers were evaluated. Hematoxylin and eosin-stained, paraffin-embedded synovial tissue sections from patients with inflammatory arthritis were assessed in order to determine the proportion of graded synovial fragments, total area of graded synovial tissue, and synovitis score per procedure. RNA quantity (μg of RNA) and quality (RNA integrity number) per procedure were also assessed in the synovial samples.

RESULTS

In this study, 84 of the 159 procedures performed on large joints at baseline (25 arthroscopic, 35 US-P&F, 11 US-NB, and 13 BN biopsies), 41 of the 159 procedures performed on small joints at baseline (11 US-P&F, 20 US-NB, and 10 BN biopsies), and 34 sequential biopsy procedures were evaluated. Compared to all other techniques evaluated in the small and large joints, fewer small joint BN biopsies and a significantly lower proportion of large joint BN biopsies yielded graded synovial tissue. No significant difference in either the proportion of graded tissue samples or total graded synovial tissue area between the US-NB and arthroscopic large joint procedures was demonstrated. Among the sequential biopsy procedures evaluated (small joint US-NB, large joint arthroscopy, US-P&F biopsy, and BN biopsy), no significant difference in the proportion of graded synovial tissue or total graded synovial tissue area was demonstrated. All procedures yielded RNA of significant quality and quantity for subsequent transcriptomic analysis.

CONCLUSION

These data support the integration of US-guided methods along with arthroscopic biopsy for clinical trial protocols in which sequential sampling of synovium from the large and small joints is needed for both histologic and molecular analysis. BN biopsy may be considered if graded synovial tissue is not required for subsequent analyses.

The Relationship Between Synovial Pathobiology and Magnetic Resonance Imaging Abnormalities in Rheumatoid Arthritis: A Systematic Review

Objective.

Magnetic resonance imaging (MRI) has been increasingly recognized as a critical tool for the assessment of patients with rheumatoid arthritis (RA) and is able to reliably identify synovitis, bone marrow edema, bone erosion, and joint space narrowing (JSN)/cartilage loss. Understanding the exact relationship between each MRI feature and local synovial pathobiology is critical to dissect disease pathogenesis as well as develop future predictive models.

Methods.

A systematic review was performed of the current published literature examining the relationship between MRI abnormalities and synovial pathobiology in patients with RA.

Results.

Eighteen studies were identified; most focused on validation of MRI as a tool to detect and quantify synovitis, with a significant relationship demonstrated. Additionally, from the limited data available, a critical role seems likely for synovial pathways, at least in driving joint damage. However, there was a lack of data examining the relationship between synovial pathobiology and bone marrow abnormalities and JSN.

Conclusion.

Although understanding the interrelationship of these disease biomarkers offers the potential to enhance the predictive validity of modern imaging with concomitant synovial pathobiological analysis, further studies integrating MRI with synovial tissue analysis in well-controlled cohorts at distinct disease stages before and after therapeutic intervention are required to achieve this.

Rheumatoid arthritis

Rheumatoid arthritis is a chronic inflammatory joint disease, which can cause cartilage and bone damage as well as disability. Early diagnosis is key to optimal therapeutic success, particularly in patients with well-characterised risk factors for poor outcomes such as high disease activity, presence of autoantibodies, and early joint damage. Treatment algorithms involve measuring disease activity with composite indices, applying a treatment-to-target strategy, and use of conventional, biological, and newz non-biological disease-modifying antirheumatic drugs. After the treatment target of stringent remission (or at least low disease activity) is maintained, dose reduction should be attempted. Although the prospects for most patients are now favourable, many still do not respond to current therapies. Accordingly, new therapies are urgently required. In this Seminar, we describe current insights into genetics and aetiology, pathophysiology, epidemiology, assessment, therapeutic agents, and treatment strategies together with unmet needs of patients with rheumatoid arthritis.