Seronegative rheumatoid arthritis: pathogenetic and therapeutic aspects

Body mass index stratification enables cytokine-based prediction of ACPA status and Power-Doppler disease activity in rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis can be classified according to ACPA and RF status. ACPA status may be associated with other pathophysiological differences, e.g., the cytokines driving inflammation. Obesity influences the course of RA, likely involving leptin; the exact mechanisms are not completely understood. This study investigates BMI influence on RA cytokine profiles and the possibility of predicting ACPA status and disease activity measured by Power-Doppler sonography (PDS).

METHODS

Patients were examined using a multi-biomarker disease assay and PDS examination of wrists and MCP and PIP joints and stratified according to ACPA status and BMI, using prediction precision to determine BMI cutoff. Analysis was performed using elastic net regularization of logistic and multiple regression. We then attempted to predict ACPA status/PDS activity based on a bootstrap approach.

RESULTS

A total of 120 measurements from 95 patients were performed. ACPA status prediction peaked at BMI 26 kg/m2, with AUC 0.82. PDS activity prediction had a mean average error of < 1.6 PDS points for all groups. In obese patients, cytokine profiles appear to align in ACPA-positive and -negative patients, with leptin playing a greater role in predicting PDS activity, but with some remaining differences.

CONCLUSION

When stratified according to BMI, cytokine patterns can predict ACPA status and PDS activity in RA with a high degree of precision. This indicates that studies into the pathophysiology of RA should take BMI into account, to differentiate between disease- and obesity-associated phenomena. The underlying pathological processes of ACPA-negative and -positive RA appear different. Multi-cytokine evaluations may provide a deeper understanding of disease processes. Key Points • A multi-cytokine approach combined with ultrasonography and modern mathematical methods can contribute to a deeper understanding of the relationship between systemic and joint inflammation. • BMI influences cytokine profiles in rheumatoid arthritis and appears to "override" disease-specific processes. • Using cytokines only, and adjusting for BMI, it is possible to predict the ACPA status and joint inflammation with considerable precision.

Rheumatoid arthritis increases the risk of heart failure: results from the cross-sectional study in the US population and mendelian randomization analysis in the European population

Objective

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease. Among its various complications, heart failure (HF) has been recognized as the second leading cause of cardiovascular death in RA patients. The objective of this study was to investigate the relationship between RA and HF using epidemiological and genetic approaches.

Methods

The study included 37,736 participants from the 1999-2020 National Health and Nutrition Examination Survey. Associations between RA and HF in the US population were assessed with weighted multivariate logistic regression analysis. A two-sample Mendelian randomization (MR) analysis was employed to establish the causal relationship between the two variables. The primary analysis method utilized was inverse variance weighting (IVW). Additionally, horizontal pleiotropy and heterogeneity were assessed to account for potential confounding factors. In cases where multiple independent datasets were accessible during MR analysis, we combined the findings through a meta-analytical approach.

Results

In observational studies, the prevalence of HF in combination with RA reached 7.11% (95%CI 5.83 to 8.39). RA was positively associated with an increased prevalence of HF in the US population [odds ratio (OR):1.93, 95% confidence interval (CI):1.47-2.54, P < 0.0001]. In a MR analysis utilizing a meta-analytical approach to amalgamate the results of the IVW method, we identified a significant causal link between genetically predicted RA and a heightened risk of HF (OR = 1.083, 95% CI: 1.028-1.141; P = 0.003). However, this association was not deemed significant for seronegative RA (SRA) (OR = 1.028, 95% CI: 0.992-1.065; P = 0.126). These findings were consistent across sensitivity analyses and did not indicate any horizontal pleiotropy.

Conclusion

RA correlates with an elevated prevalence of HF within the US population. Furthermore, genetic evidence derived from European populations underscores a causal link between RA and the risk of HF. However this association was not significant in SRA.

Polyautoimmunity in Patients With Anticyclic Citrullinated Peptide Antibody-Positive and -Negative Rheumatoid Arthritis: a Nationwide Cohort Study From Denmark

OBJECTIVE

This study aimed to compare the prevalence and incidence of polyautoimmunity between anticyclic citrullinated peptide antibody (anti-CCP)-positive and anti-CCP-negative patients with rheumatoid arthritis (RA).

METHODS

In a nationwide register-based cohort study, patients with RA (disease duration ≤ 2 yrs) in the DANBIO rheumatology register with an available anti-CCP test in the Register of Laboratory Results for Research were identified. The polyautoimmunity outcome included 21 nonrheumatic autoimmune diseases identified by linkage between the Danish Patient Registry and Prescription Registry. The age- and sex-adjusted prevalence ratio (PR) was calculated by modified Poisson regression to estimate the prevalence at diagnosis in anti-CCP-positive vs anti-CCP-negative patients. The hazard ratio (HR) of polyautoimmunity within 5 years of entry into DANBIO was estimated in cause-specific Cox regression models.

RESULTS

The study included 5839 anti-CCP-positive and 3799 anti-CCP-negative patients with RA. At first visit, the prevalence of prespecified polyautoimmune diseases in the Danish registers was 11.1% and 11.9% in anti-CCP-positive and anti-CCP-negative patients, respectively (PR 0.93, 95% CI 0.84-1.05). The most frequent autoimmune diseases were autoimmune thyroid disease, inflammatory bowel disease, and type 1 diabetes mellitus. During a mean follow-up of 3.5 years, only a few (n = 210) patients developed polyautoimmunity (HR 0.6, 95% CI 0.46-0.79).

CONCLUSION

Polyautoimmunity as captured through the Danish National Patient Registry occurred in approximately 1 in 10 patients with RA at time of diagnosis regardless of anti-CCP status. In the years subsequent to the RA diagnosis, only a few and mainly anti-CCP-negative patients developed autoimmune disease.

Rheumatoid Arthritis and Risk of Depression in South Korea

Importance

Depression is among the most common comorbidities in rheumatoid arthritis (RA). There is a lack of data regarding the association of RA seropositivity and biologic agents with depression risk among individuals with RA.

Objective

To investigate the risk of depression following RA diagnosis among patients in South Korea.

Design, Setting, and Participants

This retrospective cohort study included 38 487 patients with RA and a comparison group of 192 435 individuals matched 1:5 for age, sex, and index date. Data were from the Korean National Health Insurance Service database. Participants were enrolled from 2010 to 2017 and were followed up until 2019. Participants who had previously been diagnosed with depression or were diagnosed with depression within 1 year after the index date were excluded. Statistical analysis was performed in May 2023.

Exposures

Seropositive RA (SPRA) was defined with the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes M05 and enrollment in the Korean Rare and Intractable Diseases program. Seronegative RA (SNRA) was defined with ICD-10 codes M06 (excluding M06.1 and M06.4) and a prescription of any disease-modifying antirheumatic drugs (DMARDs) for 270 days or more.

Main Outcomes and Measures

Newly diagnosed depression (ICD-10 codes F32 or F33).

Results

The mean (SD) age of the total study population was 54.6 (12.1) years, and 163 926 individuals (71.0%) were female. During a median (IQR) follow-up of 4.1 (2.4-6.2) years, 27 063 participants (20 641 controls and 6422 with RA) developed depression. Participants with RA had a 1.66-fold higher risk of depression compared with controls (adjusted hazard ratio [aHR], 1.66 [95% CI, 1.61-1.71]). The SPRA group (aHR, 1.64 [95% CI, 1.58-1.69]) and the SNRA group (aHR, 1.73 [95% CI, 1.65-1.81]) were associated with an increased risk of depression compared with controls. Patients with RA who used biologic or targeted synthetic DMARDs (aHR, 1.33 [95% CI, 1.20-1.47]) had a lower risk of depression compared with patients with RA who did not use these medications (aHR, 1.69 [95% CI, 1.64-1.74]).

Conclusions and Relevance

This nationwide cohort study found that both SPRA and SNRA were associated with a significantly higher risk of depression. These results suggest the importance of early screening and intervention for mental health in patients with RA.

Therapeutic advances in rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common immune mediated inflammatory diseases. People with rheumatoid arthritis present with pain, swelling, and stiffness that typically affects symmetrically distributed small and large joints. Without effective treatment, significant joint damage, disability, and work loss develop, owing to chronic inflammation of the joint lining (synovium). Over the past 25 years, the management of this condition has been revolutionized, resulting in substantially higher levels of disease remission and better long term outcomes. This improvement reflects a paradigm shift towards early and aggressive pharmacological intervention coupled with a proliferation in treatment choice, in turn related to enhanced pathobiological understanding and the advent of new drugs for rheumatoid arthritis. Following an overview of these developments from a historical perspective, and with a general audience in mind, this review focuses on newer, targeted treatments in an ever evolving landscape. The review highlights ongoing areas of debate and unmet need, including the proportion of patients with persistent, difficult-to-treat disease, despite recent advances. Also discussed are personalized, strategic approaches to individual patients, the role for imaging in clinical decision making, and the goal of sustained, drug free remission and disease prevention in the future.

Real-World Treatment Effectiveness of Disease-Modifying Antirheumatic Drugs by Serostatus Among Patients With Rheumatoid Arthritis

OBJECTIVE

The objective of this study was to compare the clinical effectiveness of biologic disease-modifying antirheumatic drugs (bDMARDs) or Janus kinase inhibitors (JAKi) among seropositive versus seronegative patients with rheumatoid arthritis (RA) in a real-world setting.

METHODS

We used Optum's deidentified Clinformatics Data Mart Database (January 1, 2004, to March 31, 2021) linked with outpatient laboratory test results. The study population was adult patients with RA who initiated a bDMARD or JAKi. The index date was the dispensing of the first-ever study drug. At least 1-year continuous enrollment before and after the index date was required. Disenrollment due to death after the index date was allowed. Serostatus was defined using laboratory test results or the International Classification of Diseases, 10th Revision code M05x or M06.0x any time prior to the index date. Treatment effectiveness was measured based on a claims-based composite endpoint at 1-year post index, including nonoccurrence of any of the following: addition of conventional synthetic DMARDs, addition of or switching to new bDMARDs/JAKi, initiation of glucocorticoids, increased glucocorticoid dose, or death. Log-binomial regression models were constructed to estimate the risk ratio (RR) with 95% confidence interval (CI) comparing seropositive patients with seronegative patients, adjusting for more than 60 baseline covariates.

RESULTS

We identified a total of 7813 seropositive patients and 4202 seronegative patients. The mean (±SD) age was 56.7 (±14.0) years; 77.9% were female. The risk of 1-year treatment effectiveness was 70.2% among seropositive patients and 69.8% among seronegative patients. The adjusted RR (95% CI) was 1.00 (0.98-1.02).

CONCLUSION

In this real-world cohort study, seropositive and seronegative patients with RA had similar 1-year treatment effectiveness after initiating a bDMARD/JAKi.

When Autoantibodies Are Missing: The Challenge of Seronegative Rheumatoid Arthritis

Seronegative rheumatoid arthritis (SNRA) is characterized by the absence of both rheumatoid factor (RF) and antibodies against the cyclic citrullinated protein (ACPA) in serum. However, the differences between the two forms of RA are more complex and have not yet been definitively characterized. Several lines of evidences support the idea that there are specific elements of the two forms, including genetic background, epidemiology, pathogenesis, severity of progression over time, and response to therapy. Clinical features that may differentiate SNRA from SPRA are also suggested by data obtained from classical radiology and newer imaging techniques. Although new evidence seems to provide additional help in differentiating the two forms of RA, their distinguishing features remain largely elusive. It should also be emphasized that the distinctive features of RA forms, if not properly recognized, can lead to the underdiagnosis of SNRA, potentially missing the period called the "window of opportunity" that is critical for early diagnosis, timely treatment, and better prognosis. This review aims to summarize the data provided in the scientific literature with the goal of helping clinicians diagnose SNRA as accurately as possible, with emphasis on the most recent findings available.

The Symptoms in Persons At Risk of Rheumatoid Arthritis (SPARRA) questionnaire: predicting clinical arthritis development

OBJECTIVE

There is a need to better define symptom characteristics associated with arthritis development in individuals at risk of rheumatoid arthritis (RA). We investigated whether reported symptoms in at-risk individuals could predict arthritis development and whether predictive symptoms differed between seropositive and seronegative at-risk individuals.

METHOD

At-risk individuals from four cohorts (Netherlands, UK, Sweden, and Switzerland) completed the Symptoms in Persons At Risk of Rheumatoid Arthritis (SPARRA) questionnaire. Participants had either (i) anti-citrullinated protein antibodies and/or rheumatoid factor, or (ii) relevant symptoms with or without RA antibodies. Follow up was ≥ 24 months or until clinical arthritis development. Stepwise forward selection created SPARRA prediction models for the combined group and for a seropositive subgroup.

RESULTS

Of 214 participants, the mean age was 50 years, 67% were female, and 27% (n = 58) developed clinical arthritis after a median time of 7 months. Four symptoms predicted arthritis development: self-reported joint swelling, joint pain moving from side to side (combined group only), feeling pins and needles in the joints, and often feeling fatigued (predicting non-arthritis).

CONCLUSION

Specific symptoms can provide useful information to estimate a person's RA risk. Differences in predictive symptoms between seropositive and seronegative at-risk individuals need to be further investigated. Future research is needed to determine whether changes in symptoms over time improve prediction and to determine the value of SPARRA in optimizing the selection of individuals who need to consult a rheumatologist.

Near-Infrared Imaging of Indocyanine Green Identifies Novel Routes of Lymphatic Drainage from Metacarpophalangeal Joints in Healthy Human Hands

Background: Collecting lymphatic vessel (CLV) dysfunction has been implicated in various diseases, including rheumatoid arthritis (RA). RA patients with active hand arthritis exhibit significantly reduced lymphatic clearance of the web spaces adjacent to the metacarpophalangeal (MCP) joints and a reduction in total and basilic-associated CLVs on the dorsal surface of the hand by near-infrared (NIR) imaging of indocyanine green (ICG). In this pilot study, we assessed direct lymphatic drainage from MCP joints and aimed to visualize the total lymphatic anatomy using novel dual-agent relaxation contrast magnetic resonance lymphography (DARC-MRL) in the upper extremity of healthy human subjects. Methods and Results: Two healthy male subjects >18 years old participated in the study. We performed NIR imaging along with conventional- or DARC-MRL following intradermal web space and intra-articular MCP joint injections. ICG (NIR) or gadolinium (Gd) (MRL) was administered to visualize the CLV anatomy of the upper extremity. Web space draining CLVs were associated with the cephalic side of the antecubital fossa, while MCP draining CLVs were localized to the basilic side of the forearm by near-infrared indocyanine green imaging. The DARC-MRL methods used in this study did not adequately nullify the contrast in the blood vessels, and limited Gd-filled CLVs were identified. Conclusion: MCP joints predominantly drain into basilic CLVs in the forearm, which may explain the reduction in basilic-associated CLVs in the hands of RA patients. Current DARC-MRL techniques show limited identification of healthy lymphatic structures, and further refinement in this technique is necessary. Clinical trial registration number: NCT04046146.

In silico analysis of serum miRNA profiles in seronegative and seropositive rheumatoid arthritis patients by small RNA sequencing

Rheumatoid arthritis (RA) is a refractory autoimmune disease, affecting about 1% of the world's population. RA is divided into seronegative RA and seropositive RA. However, biomarkers for discriminating between seronegative and seropositive RA have not been reported. In this study, we profiled serum miRNAs in seronegative RA patients (N-RA), seropositive RA patients (P-RA) and healthy controls (HC) by small RNA sequencing. Results indicated that compared with HC group, there were one up-regulated and four downregulated miRNAs in N-RA group (fold change ≥ 2 and P value < 0.05); compared with P-RA group, there were two up-regulated and four downregulated miRNAs in N-RA group; compared with HC group, there were three up-regulated and four downregulated miRNAs in P-RA group. Among them, the level of hsa-miR-362-5p in N-RA group was up-regulated compared with that in HC group and P-RA group, and the level of hsa-miR-6855-5p and hsa-miR-187-3p in P-RA group was upregulated compared with that in N-RA group and HC group. Validation by qPCR confirmed that serum hsa-miR-362-5p level was elevated in N-RA group. Subsequently, by analyzing the target genes using RNAhybrid, PITA, Miranda and TargetScan and functions of differential miRNAs utilizing Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), we found that the target genes and molecular pathways regulated by miRNAs in seronegative RA and seropositive RA were roughly the same, and miRNAs in these two diseases may participate in the occurrence and development of diseases by regulating the immune system. In conclusion, this study revealed the profiles of serum miRNAs in seronegative and seropositive RA patients for the first time, providing potential biomarkers and targets for the diagnosis and treatment of seronegative and seropositive RA.

High-frequency ultrasound in patients with seronegative rheumatoid arthritis

This study aimed to investigate the value of high-frequency ultrasound (HFUS) in differentiation of the seronegative rheumatoid arthritis (SNRA) and osteoarthritis (OA) and in the diagnosis of SNRA. 83 patients diagnosed with SNRA (SNRA group) and 40 diagnosed with OA (OA group) who received HFUS were retrospectively analyzed. The grayscale (GS) scores, power Doppler (PD) scores, and bone erosion (BE)scores were recorded, and added up to calculate the total scores of US variables. The correlations of the total scores of US variables with the 28-joint disease activity score (DAS28), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were analyzed. The diagnostic efficacy of the total scores of US variables for SNRA was assessed. In the SNRA group, the detection rate of abnormal US findings in the joints and tendons by GS and PD as well as BE was higher than those in the OA group. There were significant differences between the two groups in GS scores and PD scores of joints and tendons, and BE scores of joints (P < 0.05). In the SNRA group, the total scores of most US variables were positively correlated with CRP, ESR, and DAS28 (P < 0.05), while such correlations were not observed in the OA group (P > 0.05). Among different US variables, the diagnostic value of total PD scores of the joints was the highest for SNRA. HFUS could be used to differentiate SNRA from OA and make a diagnosis of SNRA based on joint and tendon synovial sheath assessment.

Evaluation of tenosynovitis in patients with seronegative rheumatoid arthritis using microvascular flow imaging

OBJECTIVES

The purpose of this research was investigate the potential use of MVFI (microvascular flow imaging) in the assessment of tenosynovitis in cases with SNRA (seronegative rheumatoid arthritis).

METHODS

Fifty-six SNRA cases and 20 HCs (healthy controls) were enrolled, and all of them were subjected to ultrasonographic examination of the compartments I-VI of the extensor tendons of the wrist, flexor carpi radialis and flexor tendons of the five digits. Each tendon synovial sheath was semi-quantitatively scored by GS (gray-scale) ultrasound, PD (power Doppler) ultrasound, and MVFI. The PD and MVFI scores for each tendon synovial sheath were added up for each patient to get the total scores. GS scores, PD scores, and MVFI scores of tendon synovial sheaths were compared between the two groups. The correlations of total PD scores and total MVFI scores with DAS28 (disease activity scores in 28 joints), ESR (erythrocyte sedimentation rate), and CRP (C-reactive protein) were analyzed.

RESULTS

(1) In the HC group (480 tendons), GS revealed abnormalities in 29 (6.04%) tendon synovial sheaths. The GS score was 1.03 ± 0.18 with the predominance of GS grade 1 (96.55%). In the SNRA group (1,344 tendons), GS detected abnormalities in 418 tendon synovial sheaths (31.10%). The GS score was 1.97 ± 0.53 with the predominance of GS grade 2 (71.77%). There were significant differences in the GS examination rate and grade for tenosynovitis between the two groups (P < 0.05). (2) In the SNRA group, involvement of the extensor carpi ulnaris in the 6^th dorsal compartment was the most common among all extensor tendons; the flexor tendon of the third digit was the most commonly affected among all flexor tendons. (3) In the HC group, the MVFI and PD scores were 0 for tendon synovial sheaths upon GS examination. In the SNRA group, the blood flow display rate of abnormal tendon synovial sheaths indicated by GS was 83.49% and 64.59% upon MVFI and PD, respectively. The results of the two imaging techniques were significantly different (P < 0.05). The blood flow grade of abnormal tendon synovial sheaths indicated by GS was significantly different between MVFI and PD (P < 0.05), which was higher upon MVFI than PD. (4) The total MVFI score and the total PD score in the SNRA group were correlated positively with CRP, ESR and DAS28 (P < 0.05).

CONCLUSION

MVFI is a more sensitive way in detection of blood flow in the tendon synovial sheaths of SNRA cases, which may be used in clinic to evaluate disease activity and tenosynovitis in SNRA cases.

Frequency and Predictors of Opioid Use in Rheumatoid Arthritis and Seronegative Spondyloarthropathy Patients

BACKGROUND

Pain is one of the most challenging symptoms in patients with rheumatoid arthritis (RA) and spondyloarthropathies (SpAs), and pain relief is one of the top priorities for improving health-related quality of life. When medication therapy does not significantly reduce pain, chronic opioid consumption becomes more prominent in such patients. This study aimed to evaluate the state of opioid use in RA and SpA patients.

METHODS

This cross-sectional study was performed on 316 patients with RA and spondyloarthropathies (SpAs) from January to March 2014. The convenience sampling method was used to select the participants, and by obtaining verbal consent, everyone was given 15 minutes to complete a checklist independently. Demographic and opioid use data were evaluated in terms of opioid use and its predictors. In this regard, univariate and multivariate logistic regressions were used to evaluate the predictors of opioid consumption in patients. All analyses were conducted using SPSS 21 and the significance level was set at P<0.05.

FINDINGS

About 9.5% of all participants, including 8.8% of RA and 22.6% of SpA cases, were opioid abusers. In the first step of the analysis, it was observed that opioid abuse was significantly higher in men, married participants, urban residents, patients with no biological therapy, and patients with a negative family history of addiction. The most prevalent ways of drug abuse were smoking and ingestion. The results of univariate logistic regression analysis revealed SpA and other factors significantly increase the chance of opioid abuse. Furthermore, multivariate logistic regression analysis showed male gender (OR=10.4) and negative family history of addiction (OR=3.19) significantly affected addiction in RA and SpA patients with a 95% confidence interval.

CONCLUSION

Lack of suitable responsiveness to medication therapy to relieve pain, inconsistent pain evaluation, and shame of asking direct questions about addiction in RA and SpA patients may lead to opioid consumption in some cases. Seronegative SpA may make patients more prone to addiction. However, in this study, male gender and no family history of addiction were related to opioid abuse.

Periodontitis in Italian patients with established rheumatoid arthritis: A cross-sectional study

OBJECTIVE

To assess the prevalence and severity of periodontitis (P) among Italian patients affected by rheumatoid arthritis (RA).

MATERIALS AND METHODS

A full-mouth periodontal examination and a rheumatologic examination were performed. RA disease activity was scored using the DAS28. Serum analyses investigated levels of rheumatoid factor, anti-citrullinated protein antibodies (ACPAs), C-reactive protein, erythrocyte sedimentation rate and fibrinogen. Information concerning smoking, body mass index and RA medical therapy was collected. Data were analysed by Student's t test, chi-square test, binary logistic regression and Spearman's rank.

RESULTS

This cross-sectional study included 120 subjects, 77 had both diseases while 43 only had RA. The number of teeth present was statistically lower in the RA-P compared to the RA group (p < .05). There were statistically more subjects seropositive for ACPAs in the RA-P group (62.3% vs. 32.6%, p < .05). RA-P patients had an adjusted OR = 2.9 of presenting a moderate-severe DAS28 score (DAS28 ≥ 3.2).

CONCLUSIONS

Higher prevalence of severe P was noted among RA subjects. The clinical severity of RA was strongly correlated with the clinical periodontal parameters, and RA subjects also affected by P had an OR of 2.9 for presenting with a moderate-severe RA (DAS28 score ≥ 3.2).

Disease mechanisms in preclinical rheumatoid arthritis: A narrative review

In the last decades, the concept of preclinical rheumatoid arthritis (RA) has become established. In fact, the discovery that disease mechanisms start years before the onset of clinical RA has been one of the major recent insights in the understanding of RA pathogenesis. In accordance with the complex nature of the disease, preclinical events extend over several sequential phases. In a genetically predisposed host, environmental factors will further increase susceptibility for incident RA. In the initial steps of preclinical disease, immune disturbance mechanisms take place outside the joint compartment, namely in mucosal surfaces, such as the lung, gums or gut. Herein, the persistent immunologic response to altered antigens will lead to breach of tolerance and trigger autoimmunity. In a second phase, the immune response matures and is amplified at a systemic level, with epitope spreading and widening of the autoantibody repertoire. Finally, the synovial and bone compartment are targeted by specific autoantibodies against modified antigens, initiating a local inflammatory response that will eventually culminate in clinically evident synovitis. In this review, we discuss the elaborate disease mechanisms in place during preclinical RA, providing a broad perspective in the light of current evidence.

Metabolomics in rheumatoid arthritis: Advances and review

Rheumatoid arthritis (RA) is an autoimmune disease accompanied by metabolic alterations. The metabolic profiles of patients with RA can be determined using targeted and non-targeted metabolomics technology. Metabolic changes in glucose, lipid, and amino acid levels are involved in glycolysis, the tricarboxylic acid cycle, the pentose phosphate pathway, the arachidonic acid metabolic pathway, and amino acid metabolism. These alterations in metabolic pathways and metabolites can fulfill bio-energetic requirements, promote cell proliferation, drive inflammatory mediator secretion, mediate leukocyte infiltration, induce joint destruction and muscle atrophy, and regulate cell proliferation, which may reflect the etiologies of RA. Differential metabolites can be used as biomarkers for the diagnosis, prognosis, and risk prediction, improving the specificity and accuracy of diagnostics and prognosis prediction. Additionally, metabolic changes associated with therapeutic responses can improve the understanding of drug mechanism. Metabolic homeostasis and regulation are new therapeutic strategies for RA. In this review, we provide a comprehensive overview of advances in metabolomics for RA.

Seronegative rheumatic arthritis has milder inflammation and bone erosion in an ultrasound study of disease-modifying anti-rheumatic drugs (DMARDs)-naïve Chinese cohort

Background

Compared with the seropositive rheumatic arthritis (sp-RA), seronegative rheumatic arthritis (sn-RA) lacks ultrasound (US) research. It is unknown whether sn-RA patients had more severe synovitis than sp-RA ones at the same level of swollen joint counts (SJCs). We designed the US study to find out the answers.

Methods

All cases satisfied the 2010 classification criteria, first diagnosed and disease-modifying anti-rheumatic drugs (DMARDs) naïve with the characteristics of abnormal swelling or pain in the wrist, proximal interphalangeal (PIPs), and metacarpophalangeal (MCPs) joints. Demographic data was collected. US examinations, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), visual analogue scale scores (VASs), patient global assessment (PGA), physician’s global assessment (PhGA), disease activity score of 28 joints (DAS28), and van der Heijde-modified Sharp score (vdHSS) were used to evaluate the disease activity among these groups. Anticitrullinated peptide antibody (ACPA), rheumatoid factor (RF) and SJCs were used to divide the patients into 3 groups, which were defined as follows: Group A, sp-RA (positive RF and/or ACPA) with SJC >10; Group B, sp-RA with SJC ≤10; and Group C, sn-RA (all negative RF and ACPA with SJC >10 due to the criteria).

Results

A total of 139 cases were recruited. Fifty-six were Group A, 54 were Group B, and 29 were Group C. All indexes above and the total US scores were significantly lower in Group C than Group A (both groups with SJC >10) (ESR, CRP, VASs, PGA, PhGA, DAS28, vdHSS, US total score respectively: 58.8 vs. 37.5, P=0.009; 37.5 vs. 17.8, P=0.008; 61.7 vs. 52.8, P=0.032; 62.2 vs. 53.9, P=0.031; 59.8 vs. 48.3, P=0.029; 6.92 vs. 5.56, P=0.000; 61.7 vs. 44.5, P=0.023; 31.4 vs. 20.9, P=0.000). The difference of the total US scores above was mostly contributed by the symptoms of synovitis. The total US scores were prominently lower in Group C with the duration over 2 years (2–5 years, >5 years, respectively compared to <2 years: 16.3 vs. 27.4, P=0.044; 16.5 vs. 27.4, P=0.048), and vdHSS were remarkably higher in almost all groups with a duration of over 5 years. For the patients with a duration over 2 years, bone erosions occurred earlier in sp-RA than in sn-RA patients.

Conclusions

Sn-RA patients had milder synovitis than sp-RA ones at the same extent of disease activity. In addition, sn-RA had delayed progress of bone erosion than the sp-RA group.

Baseline Anti-Citrullinated Protein Antibody Status and Response to Abatacept or Non-TNFi Biologic/Targeted-Synthetic DMARDs: US Observational Study of Patients with RA

INTRODUCTION

Patients with rheumatoid arthritis (RA) may respond to treatments differently based on their underlying serology and biomarker status, but real-world data comparing treatment responses to abatacept versus other non-TNFi biologic or targeted-synthetic DMARDs by anti-citrullinated protein antibody (ACPA) status remain limited. We assessed the association between ACPA status and response to treatment in patients with RA.

METHODS

Adults from CorEvitas' RA Registry were identified who initiated abatacept, rituximab, tocilizumab, or tofacitinib, and had ACPA measured at/prior to treatment initiation and at the 6-month follow-up visit. Three cohorts were included: abatacept/rituximab (2006-2019), abatacept/tocilizumab (2010-2019), and abatacept/tofacitinib (2012-2019). Patient characteristics at initiation were compared by ACPA status (positive [+], anti-cyclic citrullinated peptide-2 [anti-CCP2] ≥ 20 U/ml; negative [-], anti-CCP2 < 20 U/ml). Outcomes over 6 months: changes in Clinical Disease Activity Index (CDAI), modified Health Assessment Questionnaire (mHAQ), patient global assessment (PGA) scores, and proportion of patients achieving a clinical response. Adjusted mean differences and odds ratios were estimated using mixed-effects linear regression models.

RESULTS

Overall, 982 abatacept, 246 rituximab, 404 tocilizumab, and 429 tofacitinib initiators were identified. ACPA+ (vs. ACPA-) patients had longer disease duration and more erosive disease. During most time periods adjusted mean changes in CDAI, mHAQ, and PGA scores and the proportion of patients achieving a clinical response were significantly higher for ACPA+ versus ACPA- patients initiating abatacept. Adjusted mean change in PGA score and patient fatigue were significantly higher for ACPA+ versus ACPA- patients initiating rituximab. No significant differences were seen by ACPA status for patients initiating tocilizumab or tofacitinib.

CONCLUSIONS

Patients who initiated abatacept or rituximab and were ACPA+ had a greater clinical response at 6-month follow-up post index compared to patients who were ACPA- treated with the same biologic.

Mechanisms underlying DMARD inefficacy in difficult-to-treat rheumatoid arthritis: a narrative review with systematic literature search

Management of RA patients has significantly improved over the past decades. However, a substantial proportion of patients is difficult-to-treat (D2T), remaining symptomatic after failing biological and/or targeted synthetic DMARDs. Multiple factors can contribute to D2T RA, including treatment non-adherence, comorbidities and co-existing mimicking diseases (e.g. fibromyalgia). Additionally, currently available biological and/or targeted synthetic DMARDs may be truly ineffective (‘true’ refractory RA) and/or lead to unacceptable side effects. In this narrative review based on a systematic literature search, an overview of underlying (immune) mechanisms is presented. Potential scenarios are discussed including the influence of different levels of gene expression and clinical characteristics. Although the exact underlying mechanisms remain largely unknown, the heterogeneity between individual patients supports the assumption that D2T RA is a syndrome involving different pathogenic mechanisms.

Functional Interactions Between lncRNAs/circRNAs and miRNAs: Insights Into Rheumatoid Arthritis

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases that affect synovitis, bone, cartilage, and joint. RA leads to bone and cartilage damage and extra-articular disorders. However, the pathogenesis of RA is still unclear, and the lack of effective early diagnosis and treatment causes severe disability, and ultimately, early death. Accumulating evidence revealed that the regulatory network that includes long non-coding RNAs (lncRNAs)/circular RNAs (circRNAs), micro RNAs (miRNAs), and messenger RNAs (mRNA) plays important roles in regulating the pathological and physiological processes in RA. lncRNAs/circRNAs act as the miRNA sponge and competitively bind to miRNA to regulate the expression mRNA in synovial tissue, FLS, and PBMC, participate in the regulation of proliferation, apoptosis, invasion, and inflammatory response. Thereby providing new strategies for its diagnosis and treatment. In this review, we comprehensively summarized the regulatory mechanisms of lncRNA/circRNA-miRNA-mRNA network and the potential roles of non-coding RNAs as biomarkers and therapeutic targets for the diagnosis and treatment of RA.

Human Carbamylome description identifies carbamylated α2-macroglobulin and Hemopexin as two novel autoantigens in early rheumatoid arthritis

OBJECTIVES

Anti-carbamylated protein antibodies (anti-CarPA) are present in rheumatoid arthritis (RA) sera and have been associated with erosive disease. The exact targets of anti-CarPA in vivo are currently not well known; we used a proteomic approach on serum and synovial fluid (SF) of RA patients to assess the human carbamylome and to identify carbamylated autoantigens as potential biomarkers in early RA.

METHODS

Mass spectrometry was performed on SF and serum from RA patients. Carbamylated proteins present in both sample types were selected as candidate autoantigens for the establishment of ELISAs. A cohort of early RA patients was tested for positivity for specific anti-CarPA.

RESULTS

Eleven novel carbamylated proteins were identified, and five were selected as potential autoantigens for detection of anti-CarPA. Among them, antibodies against carbamylated Hemopexin (anti-CaHPX) and Alpha-2-macroglobulin (anti-CaA2M) showed comparable diagnostic value to the established carbamylated fetal calf serum-based ELISA. A cohort of 189 early RA patients was studied. The combination of these new biomarkers with antibodies against citrullinated peptides and rheumatoid factor identified 89% of early RA patients in our cohort. There was little correlation between the tested biomarkers, and each one of the tested antigens could identify a different subset of seronegative RA patients. Anti-CaA2M positivity showed clinical potential, being associated with higher disease disability.

CONCLUSION

We highlight the detection of novel carbamylated autoantigens in vivo using a combined proteomic approach in SF and serum of RA patients. Anti-CaHPX and anti-CaA2M are promising clinical biomarkers, especially in seronegative RA.

Ex vivo Demonstration of Functional Deficiencies in Popliteal Lymphatic Vessels From TNF-Transgenic Mice With Inflammatory Arthritis

Background: Recent studies demonstrated lymphangiogenesis and expansion of draining lymph nodes during chronic inflammatory arthritis, and lymphatic dysfunction associated with collapse of draining lymph nodes in rheumatoid arthritis (RA) patients and TNF-transgenic (TNF-Tg) mice experiencing arthritic flare. As the intrinsic differences between lymphatic vessels afferent to healthy, expanding, and collapsed draining lymph nodes are unknown, we characterized the ex vivo behavior of popliteal lymphatic vessels (PLVs) from WT and TNF-Tg mice. We also interrogated the mechanisms of lymphatic dysfunction through inhibition of nitric oxide synthase (NOS). Methods: Popliteal lymph nodes (PLNs) in TNF-Tg mice were phenotyped as Expanding or Collapsed by in vivo ultrasound and age-matched to WT littermate controls. The PLVs were harvested and cannulated for ex vivo functional analysis over a relatively wide range of hydrostatic pressures (0.5-10 cmH2O) to quantify the end diastolic diameter (EDD), tone, amplitude (AMP), ejection fraction (EF), contraction frequency (FREQ), and fractional pump flow (FPF) with or without NOS inhibitors Data were analyzed using repeated measures two-way ANOVA with Bonferroni's post hoc test. Results: Real time videos of the cannulated PLVs demonstrated the predicted phenotypes of robust vs. weak contractions of the WT vs. TNF-Tg PLV, respectively. Quantitative analyses confirmed that TNF-Tg PLVs had significantly decreased AMP, EF, and FPF vs. WT (p < 0.05). EF and FPF were recovered by NOS inhibition, while the reduction in AMP was NOS independent. No differences in EDD, tone, or FREQ were observed between WT and TNF-Tg PLVs, nor between Expanding vs. Collapsed PLVs. Conclusion: These findings support the concept that chronic inflammatory arthritis leads to NOS dependent and independent draining lymphatic vessel dysfunction that exacerbates disease, and may trigger arthritic flare due to decreased egress of inflammatory cells and soluble factors from affected joints.

Large joints are progressively involved in rheumatoid arthritis irrespective of rheumatoid factor status-results from the early rheumatoid arthritis study

This study aimed to examine the progression of large joint involvement from early to established RA in terms of range of movement (ROM) and time to joint surgery, according to the presence of rheumatoid factor (RF). We used a historical longitudinal cohort of early RA patients. Patients were deemed RF negative if all repeated assessments were negative. The rate of progression from normal to any loss of range of movement (ROM) from years 3 to 14 were modelled using generalized estimating equations, for elbows, wrists, hips, knees and ankle, adjusting for confounders. Time to joint surgery was analysed using multivariable Cox models. A total of 1458 patients were included (66% female, mean age 55 years) and 74% were RF-positive. The prevalence of any loss of ROM, from year 3 through to 14 was highest in the wrist followed by ankle, knee, elbow and hip. Odds of loss of ROM increased over time in all joint regions assessed, at around 7–13% per year from year 3 to 14. Time to surgery was similar according to RF-status for the wrist and ankle, but RF-positive cases had a lower hazard of surgery at the elbow (HR 0.37, 0.15–0.90), hip (HR 0.69, 0.48–0.99) and after 10 years at the knee (HR 0.41, 0.25–0.68). Large joints become progressively involved in RA, most frequently affecting the wrist followed by ankle, which is overlooked in composite disease activity indices. RF-negative and positive cases progressed similarly. Treat-to-target approaches should be followed irrespective of RF status.

Chronic Pain in Patients with Rheumatoid Arthritis

PURPOSE OF REVIEW

Chronic pain is highly prevalent in patients with rheumatoid arthritis (RA) and can cause various physical and psychological impairments. Unfortunately, the appropriate diagnosis of chronic pain syndromes in this population can be challenging because pain may be primary to RA-specific inflammation and/or secondary to other conditions, typically osteoarthritis (OA) and fibromyalgia (FM). This disparity further poses a clinical challenge, given that chronic pain can often be discordant or undetected with standard RA-specific surveillance strategies, including serological markers and imaging studies. In this review, we provide a robust exploration of chronic pain in the RA population with emphasis on epidemiology, mechanisms, and management strategies.

RECENT FINDINGS

Chronic pain associated with RA typically occurs in patients with anxiety, female sex, and elevated inflammatory status. Up to 50% of these patients are thought to have chronic pain despite appropriate inflammatory suppression, typically due to peripheral and central sensitization as well as secondary OA and FM. In addition to the standard-of-care management for OA and FM, patients with RA and chronic pain benefit from behavioral and psychological treatment options. Moreover, early and multimodal therapies, including non-pharmacological, pharmacological, interventional, and surgical strategies, exist, albeit with varying efficacy, to help suppress inflammation, provide necessary analgesia, and optimize functional outcomes. Overall, chronic pain in RA is a difficult entity for both patients and providers. Early diagnosis, improved understanding of its mechanisms, and initiation of early, targeted approaches to pain control may help to improve outcomes in this population.

Quantifying Potential Cost-Savings Through an Alternative Imaging-Based Diagnostic Process in Presumptive Seronegative Rheumatoid Arthritis

Background

Seronegative rheumatoid arthritis (SRA) is a condition that is not well understood and difficult to confirm by a conventional diagnostic process. We aimed to quantify the potential cost-savings of an alternative diagnostic process (ADP) imaging-based, for patients with presumptive SRA from everyday clinical practice.

Methods

We performed a retrospective analysis for patients with presumptive SRA who tested negative for both rheumatoid factor and anti-cyclic citrullinated peptide antibodies, through an ADP imaging-based, that is a standard clinical practice in our center. After we confirmed the diagnosis of SRA or reclassified patients in terms of another proper diagnosis, we estimate direct costs in two scenarios: a conventional and ADP. We compared the cost of RA treatment during the first year against the cost of the most misdiagnosed treatment (osteoarthritis) found after applying the ADP to determine potential cost-savings.

Results

We included 440 patients with a presumptive diagnosis of SRA. According to the imaging-based ADP, SRA was confirmed in 106/440 (24.1%), unspecified RA in 9/440 (2.0%), and osteoarthritis in 325/440 (73.9%) of those patients. Although the costs of conventional diagnosis per patient is lower than those of ADP ($59,20 USD vs $269,57 USD), we found a potential drug cost-savings of $1,570,775.20 US Dollars after 1 year of correct treatment.

Conclusion

An alternative diagnosis process, including X-rays, US and MRI imaging, and clinical and blood-test assessment, not only increased diagnostic certainty in patients referred for evaluation of presumptive SRA but also suggested a potential cost-savings in pharmacological treatments avoided in misdiagnosed patients.

Autoantibody Discovery, Assay Development and Adoption: Death Valley, the Sea of Survival and Beyond

Dating to the discovery of the Lupus Erythematosus (LE) cell in 1948, there has been a dramatic growth in the discovery of unique autoantibodies and their cognate targets, all of which has led to the availability and use of autoantibody testing for a broad spectrum of autoimmune diseases. Most studies of the sensitivity, specificity, commutability, and harmonization of autoantibody testing have focused on widely available, commercially developed and agency-certified autoantibody kits. However, this is only a small part of the spectrum of autoantibody tests that are provided through laboratories world-wide. This manuscript will review the wider spectrum of testing by exploring the innovation pathway that begins with autoantibody discovery followed by assessment of clinical relevance, accuracy, validation, and then consideration of regulatory requirements as an approved diagnostic test. Some tests are offered as "Research Use Only (RUO)", some as "Laboratory Developed Tests (LDT)", some enter Health Technology Assessment (HTA) pathways, while others are relegated to a "death valley" of autoantibody discovery and become "orphan" autoantibodies. Those that achieve regulatory approval are further threatened by the business world's "Darwinian Sea of Survival". As one example of the trappings of autoantibody progression or failure, it is reported that more than 200 different autoantibodies have been described in systemic lupus erythematosus (SLE), a small handful (~10%) of these have achieved regulatory approval and are widely available as commercial diagnostic kits, while a few others may be available as RUO or LDT assays. However, the vast majority (90%) are orphaned and languish in an autoantibody 'death valley'. This review proposes that it is important to keep an inventory of these "orphan autoantibodies" in 'death valley' because, with the increasing availability of multi-analyte arrays and artificial intelligence (MAAI), some can be rescued to achieve a useful role in clinical diagnostic especially in light of patient stratification and precision medicine.

The impact of seropositivity on the effectiveness of biologic anti-rheumatic agents: results from a collaboration of 16 registries

OBJECTIVES

RF and ACPA are used as diagnostic tools and their presence has been associated with clinical response to some biologic DMARDs (bDMARDs) in RA. This study compared the impact of seropositivity on drug discontinuation and effectiveness of bDMARDs in patients with RA, using head-to-head comparisons in a real-world setting.

METHODS

We conducted a pooled analysis of 16 observational RA registries. Inclusion criteria were a diagnosis of RA, initiation of treatment with rituximab (RTX), abatacept (ABA), tocilizumab (TCZ) or TNF inhibitors (TNFis) and available information on RF and/or ACPA status. Drug discontinuation was analysed using Cox regression, including drug, seropositivity, their interaction, adjusting for concomitant and past treatments and patient and disease characteristics and accounting for country and calendar year of bDMARD initiation. Effectiveness was analysed using the Clinical Disease Activity Index evolution over time.

RESULTS

Among the 27 583 eligible patients, the association of seropositivity with drug discontinuation differed across bDMARDs (P for interaction <0.001). The adjusted hazard ratios for seropositive compared with seronegative patients were 1.01 (95% CI 0.95, 1.07) for TNFis, 0.89 (0.78, 1.02)] for TCZ, 0.80 (0.72, 0.88) for ABA and 0.70 (0.59, 0.84) for RTX. Adjusted differences in remission and low disease activity rates between seropositive and seronegative patients followed the same pattern, with no difference in TNFis, a small difference in TCZ, a larger difference in ABA and the largest difference in RTX (Lundex remission difference +5.9%, low disease activity difference +11.6%).

CONCLUSION

Seropositivity was associated with increased effectiveness of non-TNFi bDMARDs, especially RTX and ABA, but not TNFis.

Cy3-tilmanocept labeling of macrophages in joints of mice with antibody-induced arthritis and synovium of human patients with rheumatoid arthritis

γ-Tilmanocept (^99m Tc-tilmanocept) is a receptor-directed, radiolabeled tracer that is FDA-approved for guiding sentinel lymph node biopsy. Tilmanocept binds the C-type lectin mannose receptor (MR, CD206) on macrophages. In this study, nonradioactive, fluorescently-labeled Cy3-tilmanocept was used to detect CD206⁺ mononuclear cells in the cartilage of mice with antibody-induced arthritis and in the synovial fluid and tissue of human subjects with rheumatoid arthritis (RA) for comparison with osteoarthritis (OA), and healthy volunteer (HV) controls. Murine arthritis was induced by injection of monoclonal anti-cartilage antibody followed by injection of Escherichia coli lipopolysaccharide. Post-arthritis development (7-11 days), the mice were injected intravenously with Cy3-tilmanocept followed by in vivo and ex vivo epifluorescence imaging. Two-photon imaging, immunofluorescence, and immunohistochemistry were used to identify articular and synovial macrophages (CD206, F4/80, and Cy3-tilmanocept binding) in murine tissues. Cy3-tilmanocept epifluorescence was present in arthritic knees and elbows of murine tissues; no radiographic changes were noted in the skeletons. However, inflammatory arthritic changes were apparent by histopathology and immunohistochemistry (F4/80), immunofluorescence (CD206) and Cy3-tilmanocept binding. In human RA synovial fluid, Cy3-tilmanocept staining correlated with CD206⁺ /CD16⁺ cells; negligible labeling was observed in OA samples. Cy3-tilmanocept colocalized with CD206 and staining was significantly higher in RA synovial tissue compared to OA or HV. Our results demonstrate that imaging with Cy3-tilmanocept can detect in vivo inflammatory, CD206⁺ macrophages in an early arthritis animal model and in human RA patients. These data establish a novel tool for preclinical research of early arthritis and have implications for early RA detection and monitoring of therapeutic efficacy in humans.

Influence of prognosis factors on the prescription of targeted treatments in rheumatoid arthritis: A Delphi survey

OBJECTIVES

To explore current evidence on the management of poor prognostic factors in rheumatoid arthritis (RA) and to investigate whether this evidence is taken into account by clinicians when deciding on treatment in daily clinical practice.

METHODS

We performed a systematic literature review (SLR) to analyse the effects of currently available biologic disease-modifying antirheumatic drugs (bDMARDs) and Janus kinase inhibitors (JAKi) on the classically accepted poor prognostic factors of RA. All randomized controlled trials reporting subgroup analyses about effects on prognostic factors were identified and synthesized. In a second phase, a two-round Delphi survey was carried out to contrast the SLR results with the grade of agreement of a large group of rheumatologists about the effectiveness of each drug class on each prognostic factor.

RESULTS

According to the Delphi results, the only prognostic factor that significantly influenced the selection of treatment was the presence of interstitial lung disease (ILD), being the preferred treatment in this scenario abatacept or rituximab. The rest of the poor prognostic factors (including high disease activity at baseline, disability as measured by the Health Assessment Questionnaire index, seropositivity, elevated acute-phase reactants, and evidence of erosions based on plain radiography or ultrasonography) did not seem to significantly influence rheumatologists when choosing a treatment. The results of the SLR results did not show solid evidence regarding the use of any specific therapy in the management of patients with specific poor factors, except in the case of RA-ILD, although the data in the literature in this regard are not free of bias.

CONCLUSIONS

The only prognostic factor that seems to significantly influence the selection of treatment is the presence of RA-ILD.

Prognostic Factors for Radiographic Progression in Patients with Seronegative Rheumatoid Arthritis

(1) Background: It has long been suggested that seronegative rheumatoid arthritis (RA) represents a clinical entity quite distinct from that of seropositive. However, analytical studies of seronegative RA dedicated to clinical outcomes regarding radiographic progression and related risk factors are scarce. The aim of this study is to evaluate radiographic outcome and prognostic factors for radiographic progression in patients with seronegative rheumatoid arthritis. (2) Methods: Subjects included RA patients reported as seronegative for both rheumatoid factor and anti-citrullinated protein antibody, who were treated at Jeju National University Hospital in South Korea between 2003 and 2016, including follow-up of at least 2 years. All patients fulfilled 1987 ACA or 2010 ACR/EULAR RA criteria. Radiographic progression was measured by yearly change in the Sharp van der Heijde (SvdH) score during follow-up periods. Medical records, laboratory and radiographic data were retrospectively analyzed, and linear regression analysis was performed to evaluate prognostic factors for radiographic progression in patients with seronegative rheumatoid arthritis. (3) Results: In total, 116 patients with seronegative RA were observed and 43 (37.1%) patients demonstrated radiographic damage during follow-up period. Mean age at diagnosis was 48 years and 86 (74.1%) patients were female. Symptom duration at diagnosis was 1.3 years and mean follow-up duration was 5.2 years. Patients with radiographic damage at diagnosis were 14 (12.1%) and mean SvdH score was 6.8 at diagnosis. Radiographic damage and SvdH at diagnosis significantly correlated with radiographic progression in patients with seronegative RA after adjusting age, sex, symptom duration, number of active synovitis, and CRP at diagnosis (β-coefficient 6.5 ± 1.84; p = 0.001 and β-coefficient 0.12 ± 0.02; p < 0.001, respectively). (4) Conclusions: This study determined that radiographic damage and SvdH at diagnosis were predictive factors in progression of radiographic damage in patients with seronegative rheumatoid arthritis. A large comparative study dedicated to this issue in seronegative RA is required.

Serum 14-3-3η is a Marker that Complements Current Biomarkers for the Diagnosis of RA: Evidence from a Meta-analysis

OBJECTIVE

To systematically evaluate the diagnostic value of 14-3-3η protein for rheumatoid arthritis (RA).

METHOD

Searched PubMed, Web of Science, Embase and China Biology Medicine (CBM) databases comprehensively from inception to May 2020. The evaluation index were the pooled sensitivity, specificity, diagnosis odds ratio (DOR), positive likelihood ratio (PLR), negative likelihood ratio (NLR), as well as the area under the summary receiver operating characteristic (SROC) curves. Meta-Disc 1.4 and RevMan 5.3 were used to analyze all statistics. QUADAS-2 tool was applied to evaluate the quality of eligible studies. Subgroup analysis and meta-regression were used to explore the sources of heterogeneity.

RESULTS

Nine articles containing eleven records were eligible for this meta-analysis. The pooled sensitivity of 14-3-3η was 0.63 (95% CI: 0.60 to 0.66), the pooled specificity was 0.90 (95% CI: 0.88 to 0.91). The pooled PLR and NLR was 6.10 (95% CI: 4.67 to 7.96) and 0.40 (95% CI: 0.33 to 0.48), respectively. The pooled DOR was 15.90 (95% CI: 11.15 to 22.68), and the area under the curve (AUC) was 0.8696. Compared with a single indicator (rheumatoid factor or anti-citrullinated protein antibodies), adding 14-3-3η can bring incremental benefits to the diagnosis of RA. The results of subgroup analysis and meta-regression suggested that the two factors (ethnicity, early vs established RA) we analyzed might not be the source of heterogeneity (P value were 0.0979 and 0.4298, respectively) and there was no publication bias among these articles (P = .42).

CONCLUSION

Serum 14-3-3η protein is a supplementary biomarker in the diagnosis of RA.

Plasma acrolein level in rheumatoid arthritis increases independently of the disease characteristics

OBJECTIVE

This study aimed to clarify whether plasma acrolein level actually increases in rheumatoid arthritis (RA) patients, and to elucidate whether any relationship exists between the levels and the RA background variables.

METHODS

Plasma levels of protein-conjugated acrolein (PC-Acro) in 84 patients (RA group) and 298 normal individuals (Control group) were measured by enzyme-linked immunosorbent assay procedures. The data were statistically analyzed with Wilcoxon rank-sum test, multiple logistic regression analyses and Spearman's rank correlation coefficient.

RESULTS

The RA group showed significantly higher PC-Acro levels than the Control group (median [interquartile range]: 80.5 [63.2-105.2] and 65.9 [58.9-78.1] nmol/ml, respectively). Of background factors giving influence to PC-Acro level in the combination of the two groups, 'diagnosis of RA positive' indicated strong correlation to high PC-Acro level (odds ratio: 2.96; 95% confidence interval: 1.54-5.71). These increases of PC-Acro in the RA patients did not correlate to their disease duration and/or inflammatory variables: PC-Acro level could elevate even in early RA patients showing negative inflammatory findings.

CONCLUSION

Plasma levels of PC-Acro increased with RA, but the levels did not correlate with RA background variables. This report provides the basis for further studies of early diagnosis of RA as well as its pathogenesis.

Using the Immunophenotype to Predict Response to Biologic Drugs in Rheumatoid Arthritis

Tumour necrosis factor (TNF)-α is a key mediator of inflammation in rheumatoid arthritis, and its discovery led to the development of highly successful anti-TNF therapy. Subsequently, other biologic drugs targeting immune pathways, namely interleukin-6 blockade, B cell depletion, and T cell co-stimulation blockade, have been developed. Not all patients respond to a biologic drug, leading to a knowledge gap between biologic therapies available and the confident prediction of response. So far, genetic studies have failed to uncover clinically informative biomarkers to predict response. Given that the targets of biologics are immune pathways, immunological study has become all the more pertinent. Furthermore, advances in single-cell technology have enabled the characterization of many leucocyte subsets. Studying the blood immunophenotype may therefore, define biomarker profiles relevant to each individual patient's disease and treatment outcome. This review summarises our current understanding of how immune biomarkers might be able to predict treatment response to biologic drugs.

[A systemic disease mimicking a rheumatoid arthritis]

INTRODUCTION

Rare systemic diseases such as amyloidosis can mimic inflammatory rheumatic diseases. Because of their poor prognosis, physicians should rule them out at the onset of inflammatory rheumatism. We report a case of AL amyloidosis misdiagnosed as rheumatoid arthritis.

CASE REPORT

A 71-year-old woman was referred for seronegative rheumatoid arthritis, resistant to three biologic therapies. She had an IgA lambda monoclonal gammopathy of undetermined significance (MGUS). The patient subsequently developed glomerular proteinuria. Abdominal fat and accessory salivary glands biopsies revealed amyloid light-chain (AL) amyloidosis. Treatment with bortezomib-cyclophosphamide-dexamethasone, led to complete hematologic, renal and rheumatologic remission. Ten months after treatment interruption, the patient had an articular and hematologic relapse.

CONCLUSION

Amyloid light-chain amyloidosis arthropathy is probably underdiagnosed. A review of amyloid arthropathy associated with multiple myeloma found that 33% of patients had been misdiagnosed with rheumatoid arthritis.

Mucosa-Environment Interactions in the Pathogenesis of Rheumatoid Arthritis

Mucosal surfaces play a central role in the pathogenesis of rheumatoid arthritis (RA). Several risk factors, such as cigarette smoking, environmental pollution, and periodontitis interact with the host at the mucosal level, triggering immune system activation. Moreover, the alteration of microbiota homeostasis is gaining increased attention for its involvement in the disease pathogenesis, modulating the immune cell response at a local and subsequently at a systemic level. Currently, the onset of the clinical manifest arthritis is thought to be the last step of a series of pathogenic events lasting years. The positivity for anti-citrullinated protein antibodies (ACPAs) and rheumatoid factor (RF), in absence of symptoms, characterizes a preclinical phase of RA-namely systemic autoimmune phase- which is at high risk for disease progression. Several immune abnormalities, such as local ACPA production, increased T cell polarization towards a pro-inflammatory phenotype, and innate immune cell activation can be documented in at-risk subjects. Many of these abnormalities are direct consequences of the interaction between the environment and the host, which takes place at the mucosal level. The purpose of this review is to describe the humoral and cellular immune abnormalities detected in subjects at risk of RA, highlighting their origin from the mucosa-environment interaction.

Differing X-ray patterns in seronegative and seropositive rheumatoid arthritis

INTRODUCTION

Anti-citrullinated protein antibody (ACPA) and rheumatoid factor (RF) status are important predictors for rheumatoid arthritis (RA) erosivity. Qualitative differences on hand/feet radiographs have been described, indicating more carpal fusion in seronegative RA. This study explores these differences further using the total Sharp/van der Heijde score (TSS), digital X-ray radiogrammetry (DXR), and qualitative description.

METHODS AND MATERIALS

Matched seronegative (ACPA negative, RF negative, snRA) and seropositive (ACPA, RF > 3xULN, spRA) were examined. TSS scores both for erosions and joint space narrowing (JSN) were registered separately and compared for both groups. Joint compartments and single joints were compared, using a heat map. The degree of carpal fusion was quantified 0-5. DXR measurements (bone mineral density, cortical thickness, bone width, metacarpal index) were determined for each hand separately. Finally, selected radiographs were examined unblinded to search for non-quantifiable differences.

RESULTS

A total of 56 snRA and 57 spRA patients were examined. spRA patients had more erosions and joint space narrowing. Erosion load differed significantly between spRA and snRA in the foot and metacarpophalangeal joint, but not in the wrist or proximal interphalangeal joint compartments. Intracompartmental differences were greater in spRA. JSN scores were greater in spRA, in all compartments except wrist. Carpal fusion and DXR scores did not differ between the groups. The qualitative comparison showed that snRA patients displayed periarticular ossifications, carpal shortening, and sparing of the CMC joints, whereas spRA patients had more CMC damage and less shortening.

CONCLUSION

X-ray manifestations in snRA and spRA are qualitatively and quantitatively different. This suggests pathophysiological differences between the two forms. Key Points • Seronegative and seropositive RA display qualitatively and quantitatively different X-ray patterns, suggesting differences in the underlying pathophysiological process. This is the first time that this has been shown in a systematic, quantitative fashion.

Association of Baseline Peptidylarginine Deiminase 4 Autoantibodies With Favorable Response to Treatment Escalation in Rheumatoid Arthritis

OBJECTIVE

To determine if the baseline presence of autoantibodies to peptidylarginine deiminase 4 (PAD4) predicts therapeutic response to biologic and conventional disease-modifying antirheumatic drugs (DMARDs) in patients with rheumatoid arthritis (RA) in whom methotrexate (MTX) monotherapy was unsuccessful.

METHODS

Baseline serum from 282 RA patients in whom MTX monotherapy was unsuccessful was screened for the presence of anti-PAD4 antibodies by immunoprecipitation. Clinical response to either triple DMARD (MTX, sulfasalazine, and hydroxychloroquine) or MTX/etanercept combination therapy was determined at 24 and 48 weeks post-treatment initiation. Disease activity was measured using the Disease Activity Score 28-joint assessment (DAS28), and erosive disease was quantified using the Sharp/van der Heijde scoring method. Generalized estimating equations (GEEs) were used to model the clinical responses to treatment in patients with and those without baseline anti-PAD4 antibodies.

RESULTS

Anti-PAD4 antibody positivity was associated with male sex, a history of never smoking, and anti-citrullinated protein antibodies. At baseline, patients with anti-PAD4 antibodies had longer disease duration and significantly more radiographic joint damage than anti-PAD4-negative patients, but did not differ in disease activity according to the DAS28. In unadjusted analyses and multivariable GEE models, patients with anti-PAD4 antibodies exhibited greater improvements in DAS28 (adjusted P = 0.02 and P = 0.008, respectively) and less radiographic progression (adjusted P = 0.01 and P = 0.002, respectively) compared to anti-PAD antibody-negative patients, independent of treatment received.

CONCLUSION

Although anti-PAD4 antibodies were associated with worse baseline radiographic joint damage, suggesting a history of active or undiagnosed disease, treatment escalation therapy was more effective in reducing disease activity and slowing the progression of joint damage in this patient subset.

Power-Doppler perfusion phenotype in RA patients is dependent on anti-citrullinated peptide antibody status, not on rheumatoid factor

It is not known whether there are any consistent non-serological differences between seropositive and seronegative rheumatoid arthritis, and if any, whether they depend upon rheumatoid factor (RF), anti-citrullinated peptide antibodies (ACPA), or both. In a pilot study, we showed that the two forms could be differentiated using power-Doppler sonography (PDS), and that the difference is ACPA dependent. This extended study explored whether the previous findings could be confirmed. 103 patients 51 ACPA positive (ACPA +), 52 ACPA negative (ACPA -) with active wrist arthritis were examined using PDS. By means of a temporal image series, pulsatility was evaluated over a 3-5-s period, maximum and minimum perfusion signal were determined using a computer program counting the number of coloured pixels for each frame. Maxima (P_max) and minima (P_min) were determined, and the standardized peak-to-peak amplitude sA was calculated (sA = (P_max - P_min)/P_max). This parameter was then compared for ACPA + and ACPA- patients. In addition, a multivariate regression was performed, to determine which factors influence sA. sA differed significantly between ACPA + and ACPA- patients [20% (13-26) vs. 41% (32-57), p < 0. 0001]. In the multivariate analysis, age (t = 2.5, p = 0.02) and ACPA status (t = - 4.8, p < 0.0001) were independent predictors of sA. PDS perfusion patterns are different in seropositive and seronegative RA. The difference appears to be ACPA, not RF dependent. This suggests that the underlying pathophysiological process is different in ACPA-positive and ACPA-negative RA.

What are the dominant cytokines in early rheumatoid arthritis?

Purpose of review

Rheumatoid arthritis is a systemic disease of evolving immune dysregulation that culminates in joint destruction and disability. The principle by which pro-inflammatory cytokines may be therapeutically targeted to abrogate disease is well established, but has yet to translate into reliable cures for patients. Emerging insights into cytokine-mediated pathobiology during rheumatoid arthritis development are reviewed, and their implications for future treatment strategies considered.

Recent findings

Accumulating data highlight cytokine perturbations before the clinical onset of rheumatoid arthritis. Some of these have now been linked to the arthritogenic activation of autoantibodies and associated pain and bone destruction in affected joints. These observations suggest cytokines may trigger the transition from systemic immunity to arthritis. Cytokine exposure could furthermore ‘prime’ synovial stromal cells to perpetuate a dominant pro-inflammatory environment. By facilitating cross-talk between infiltrating immune cells and even sustaining ectopic lymphoid structure development in some cases, cytokine interplay ultimately underpins the failure of arthritis to resolve.

Summary

Successful therapeutic stratification will depend upon an increasingly sophisticated appreciation of how dominant players amongst cytokine networks vary across time and anatomical space during incipient rheumatoid arthritis. The prize of sustained remission for all patients justifies the considerable effort required to achieve this understanding.

Mechanistic immunological based classification of rheumatoid arthritis

The classical autoimmunity paradigm in rheumatoid arthritis (RA) is strongly supported by immunogenetics suggesting follicular helper T-cell responses driving high titre specific autoantibodies that pre-dates disease onset. Using the immunological disease continuum model of inflammation against self with "pure" adaptive and innate immune disease at opposite boundaries, we propose a novel immune mechanistic classification describing the heterogeneity within RA. Mutations or SNPs in autoinflammatory genes including MEFV and NOD2 are linked to seronegative RA phenotypes including some so called palindromic RA cases. However, just as innate and adaptive immunity are closely functionally integrated, some ACPA+ RA cases have superimposed "autoinflammatory" features including abrupt onset attacks, severe attacks, self-limiting attacks, relevant autoinflammatory mutations or SNPs and therapeutic responses to autoinflammatory pathway therapies including colchicine and IL-1 pathway blockade. An emergent feature from this classification that non-destructive RA phenotypes, both innate and adaptive, have disease epicentres situated in the extracapsular tissues. This mixed innate and adaptive immunopathogenesis may be the key to understanding severe disease flares, resistant disease subsets that are unresponsive to standard therapy and for therapies that target the autoinflammatory component of disease that are not currently considered by expert therapeutic recommendations.

Targeting lymphatic function as a novel therapeutic intervention for rheumatoid arthritis

Although clinical outcomes for patients with rheumatoid arthritis (RA) have greatly improved with the use of biologic and conventional DMARDs, approximately 40% of patients do not achieve primary clinical outcomes in randomized trials, and only a small proportion achieve lasting remission. Over the past decade, studies in murine models point to the critical role of the lymphatic system in the pathogenesis and therapy of inflammatory-erosive arthritis, presumably by the removal of catabolic factors, cytokines and inflammatory cells from the inflamed synovium. Murine studies demonstrate that lymphatic drainage increases at the onset of inflammatory-erosive arthritis but, as inflammation progresses to a more chronic phase, lymphatic clearance declines and both structural and cellular changes are observed in the draining lymph node. Specifically, chronic damage to the lymphatic vessel from persistent inflammation results in loss of lymphatic vessel contraction followed by lymph node collapse, reduced lymphatic drainage, and ultimately severe synovitis and joint erosion. Notably, clinical pilot studies in patients with RA report lymph node changes following treatment, and thus draining lymphatic vessels and nodes could represent a potential biomarker of arthritis activity and response to therapy. Most importantly, targeting lymphatics represents an innovative strategy for therapeutic intervention for RA.

Early detection of rheumatoid arthritis in rats and humans with 99mTc-3PRGD2 scintigraphy: imaging synovial neoangiogenesis

OBJECTIVES

To validate 99mTc-labeled arginylglycylaspartic acid (99mTc-3PRGD2) scintigraphy as a means to image synovial neoangiogenesis in joints afflicted by rheumatoid arthritis and to investigate its potential in the early detection and management of rheumatoid arthritis.

METHODS

Rheumatoid arthritis and osteoarthritis were generated in Sprague Dawley rats by type II collagen immunization and papain injection, respectively. Rats were imaged with 99mTc-3PRGD2 and 99mTc- methyl diphosphonate (99mTc MDP). X-ray images were also obtained and assessed by a radiologist. Immunohistochemistry of αvβ3 and CD31confirmed the onset of synovial neoangiogenesis. The effect of bevacizumab on rheumatoid arthritis was followed with 99mTc-3PRGD2 scintigraphy. A patient with rheumatoid arthritis and a healthy volunteer were scanned with 99mTc-3PRGD2.

RESULTS

Two weeks after immunization, a significant increase in 99mTc-3PRGD2 was observed in the joints of the rheumatoid arthritis model though uptake in osteoarthritis model and untreated controls was low. 99mTc-MDP whole body scans failed to distinguish early rheumatoid arthritis joints from healthy controls. The expression of αvβ3 and CD31was significantly higher in the joints of rheumatoid arthritis rats compared to normal controls. In serial 99mTc-3PRGD2 scintigraphy studies, 99mTc-3PRGD2 uptake increased in parallel with disease progression. Bevacizumab anti-angiogenetic therapy both improved the symptoms of the rheumatoid arthritis rats and significantly decreased 99mTc-3PRGD2 uptake. Significantly higher 99mTc-3PRGD2 accumulation was also observed in rheumatoid arthritis joints in the patient.

CONCLUSIONS

Our findings indicate that 99mTc-3PRGD2 scintigraphy could detect early rheumatoid arthritis by imaging the associated synovial neoangiogenesis, and may be useful in disease management.

Components of treatment delay in rheumatoid arthritis differ according to autoantibody status: validation of a single-centre observation using national audit data

Objective. To determine whether time to treatment following symptom onset differs between RA patients according to autoantibody status.

Methods. A single-centre retrospective analysis of a UK early RA inception cohort was first undertaken to identify those components of the patient journey that differed by serological subtype. Data from a UK national audit of early inflammatory arthritis patients was accessed to replicate the key finding.

Results. A total of 173 RA patients were diagnosed over a 31-month period, of whom 80 (46%) were ACPA/RF double-seropositive (ACPA⁺/RF⁺), 53 (31%) ACPA⁻/RF⁻, 17 (10%) ACPA⁺/RF⁻ and 23 (13%) RF⁺/ACPA⁻. Overall, ACPA⁺/RF⁺ patients experienced significantly longer symptom duration before DMARD initiation. This was accounted for by delays in their presentation to primary care following symptom onset—a finding that was robustly confirmed in an independent dataset of 2192 UK early RA patients. In contrast, ACPA⁻/RF⁻ patients were significantly more likely to experience delays in DMARD initiation after presenting to secondary care.

Conclusion. Causes of treatment delays in early RA differ according to patients’ autoantibody status. More insidious symptom onset and/or distinct health-seeking behaviours among ACPA⁺/RF⁺ patients may contribute to late presentations in primary care, whereas ACPA⁻/RF⁻ patients experience delayed diagnosis and treatment in secondary care. These observations inform the research agenda, potentially influencing the design of service delivery for early arthritis patients.

Vasculitic central retinal vein occlusion: The presenting sign of seronegative rheumatoid arthritis

PURPOSE

To report the case of a patient who presented with a vasculitic central retinal vein occlusion (CRVO), which was the result of an undiagnosed systemic inflammatory condition, seronegative rheumatoid arthritis (RA).

OBSERVATIONS

The patient presented with reduced vision in the left eye and polyarthralgia. Fundoscopic examination revealed a central retinal vein occlusion (CRVO) with concurrent evidence of vasculitis. Work-up for polyarthralgia included comprehensive serologic testing for connective tissue disease, including Vectra® disease activity (DA) testing. Results of these studies confirmed the diagnosis of seronegative rheumatoid arthritis (RA). Systemic steroid therapy was initiated with subsequent anatomic and visual improvement.

CONCLUSIONS AND IMPORTANCE

We hypothesize that the systemic inflammation-a hallmark of RA-led to the development of a vasculitic CRVO and, thus, the retinal manifestations served as the disease marker that prompted thorough work-up of the patient's disease, even in the face of initial seronegativity. This case serves as a reminder that, in the setting of CRVO and polyarthralgia, systemic inflammatory conditions must be considered as the underlying etiology. Further, this case report highlights our evolving understanding of the role that serologic markers play in the diagnosis and monitoring of RA.

Long-term outcomes of destructive seronegative (rheumatoid) arthritis - description of four clinical cases

Background

Seronegative rheumatoid arthritis is associated with a milder course of progression compared to seropositive disease. However, long-term follow-up data of the clinical course of seronegative rheumatoid arthritis are sparse. Here we describe four cases with a rare disease entity of aggressive destructive seronegative (rheumatoid) arthritis with 20-35 years of follow-up.

Case presentation

The four cases are women with an initial presentation of seronegative rheumatoid arthritis in 1980-1996 and have received disease-modifying anti-rheumatic drugs since the diagnosis. In all cases, the condition has been refractory to treatments and evolved into a severe disease with destructions of the wrists, sub-talar and ankle joints, as well as large joints but not small joints of fingers and toes. All cases are negative with regard to rheumatoid factor, anti-cyclic citrullinated peptide antibodies and antibodies against carbamylated proteins.

Conclusions

This report adds to the existing literature, making the reader aware of this sub-type of inflammatory arthritis which despite being seronegative, can have devastating disease consequences. The report highlights the need for further research into this field in order to better understand this disease sub-type, the pathogenesis, disease course and outcomes.