The role of citrullinated protein antibodies in predicting erosive disease in rheumatoid arthritis: a systematic literature review and meta-analysis

The peculiar features, diversity and impact of citrulline-reactive autoantibodies

Since entering the stage 25 years ago as a highly specific serological biomarker for rheumatoid arthritis, anti-citrullinated protein antibodies (ACPAs) have been a topic of extensive research. This hallmark B cell response arises years before disease onset, displays interpatient autoantigen variability, and is associated with poor clinical outcomes. Technological and scientific advances have revealed broad clonal diversity and intriguing features including high levels of somatic hypermutation, variable-domain N-linked glycosylation, hapten-like peptide interactions, and clone-specific multireactivity to citrullinated, carbamylated and acetylated epitopes. ACPAs have been found in different isotypes and subclasses, in both circulation and tissue, and are secreted by both plasmablasts and long-lived plasma cells. Notably, although some disease-promoting features have been reported, results now demonstrate that certain monoclonal ACPAs therapeutically block arthritis and inflammation in mouse models. A wealth of functional studies using patient-derived polyclonal and monoclonal antibodies have provided evidence for pathogenic and protective effects of ACPAs in the context of arthritis. To understand the roles of ACPAs, one needs to consider their immunological properties by incorporating different facets such as rheumatoid arthritis B cell biology, environmental triggers and chronic antigen exposure. The emerging picture points to a complex role of citrulline-reactive autoantibodies, in which the diversity and dynamics of antibody clones could determine clinical progression and manifestations.

Nipocalimab, an anti-FcRn monoclonal antibody, in participants with moderate to severe active rheumatoid arthritis and inadequate response or intolerance to anti-TNF therapy: results from the phase 2a IRIS-RA study

OBJECTIVES

To investigate the efficacy, safety, pharmacokinetics and pharmacodynamics of nipocalimab in participants with moderate to severe active rheumatoid arthritis (RA) and inadequate response or intolerance to ≥1 antitumour necrosis factor agent.

METHODS

In this phase 2a study, participants with RA seropositive for anticitrullinated protein antibodies (ACPA) or rheumatoid factors were randomised 3:2 to nipocalimab (15 mg/kg intravenously every 2 weeks) or placebo from Weeks 0 to 10. Efficacy endpoints (primary endpoint: change from baseline in Disease Activity Score 28 using C reactive protein (DAS28-CRP) at Week 12) and patient-reported outcomes (PROs) were assessed through Week 12. Safety, pharmacokinetics and pharmacodynamics were assessed through Week 18.

RESULTS

53 participants were enrolled (nipocalimab/placebo, n=33/20). Although the primary endpoint did not reach statistical significance for nipocalimab versus placebo, a numerically higher change from baseline in DAS28-CRP at Week 12 was observed (least squares mean (95% CI): -1.03 (-1.66 to -0.40) vs -0.58 (-1.24 to 0.07)), with numerically higher improvements in all secondary efficacy outcomes and PROs. Serious adverse events were reported in three participants (burn infection, infusion-related reaction and deep vein thrombosis). Nipocalimab significantly and reversibly reduced serum immunoglobulin G, ACPA and circulating immune complex levels but not serum inflammatory markers, including CRP. ACPA reduction was associated with DAS28-CRP remission and 50% response rate in American College of Rheumatology (ACR) criteria; participants with a higher baseline ACPA had greater clinical improvement.

CONCLUSIONS

Despite not achieving statistical significance in the primary endpoint, nipocalimab showed consistent, numerical efficacy benefits in participants with moderate to severe active RA, with greater benefit observed for participants with a higher baseline ACPA.

TRIAL REGISTRATION NUMBER

NCT04991753.

Correlation of Professional Antigen-Presenting Tbet+CD11c+ B Cells With Bone Destruction in Untreated Rheumatoid Arthritis

OBJECTIVE

Subsets of CD21-/low memory B cells (MBCs), including double-negative (DN, CD27-IgD-) and Tbet+CD11c+ cells, are expanded in chronic inflammatory diseases. In rheumatoid arthritis (RA), CD21-/low MBCs correlate with joint destruction. However, whether this is due to the Tbet+CD11c+ subset, its function and pathogenic contribution to RA are unknown. This study aims to investigate the association between CD21-/lowTbet+CD11c+ MBCs and joint destruction as well as other clinical parameters and to elucidate their functional properties in patients with untreated RA (uRA).

METHODS

Clinical observations were combined with flow cytometry (n = 36) and single-cell RNA sequencing (scRNA-seq) and V(D)J sequencing (n = 4) of peripheral blood (PB) MBCs from patients with uRA. The transcriptome of circulating Tbet+CD11c+ MBCs was compared with scRNA-seq data of synovial B cells. In vitro coculture of Tbet+CD11c+ B cells with T cells was used to assess costimulatory capacity.

RESULTS

CD21-/lowTbet+CD11c+ MBCs in PB correlated with bone destruction but no other clinical parameters analyzed. The Tbet+CD11c+ MBCs have undergone clonal expansion and express somatically mutated V genes. Gene expression analysis of these cells identified a unique signature of more than 150 up-regulated genes associated with antigen presentation functions, including B cell receptor activation and clathrin-mediated antigen internalization; regulation of actin filaments, endosomes, and lysosomes; antigen processing, loading, presentation, and costimulation; a transcriptome mirrored in their synovial tissue counterparts. In vitro, Tbet+CD11c+ B cells induced retinoic acid receptor-related orphan nuclear receptor γT expression in CD4+ T cells, thereby polarizing to Th17 cells, a T cell subset critical for osteoclastogenesis and associated with bone destruction.

CONCLUSION

This study suggests that Tbet+CD11c+ MBCs contribute to the pathogenesis of RA by promoting bone destruction through antigen presentation, T cell activation, and Th17 polarization.

In early rheumatoid arthritis, anticitrullinated peptide antibodies associate with low number of affected joints and rheumatoid factor associates with systemic inflammation

OBJECTIVES

To investigate how individual rheumatoid arthritis (RA) autoantibodies associate with individual signs and symptoms at the time of RA diagnosis.

METHODS

IgA, IgG, IgM rheumatoid factor (RF), antibodies against cyclic citrullinated peptide version 2 (anti-CCP2) and 16 individual antibodies against citrullinated protein (ACPA) reactivities were analysed centrally in baseline sera from 1600 patients with RA classified according to the 1987 American College of Rheumatology (ACR) criteria. These results were related to C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), number of swollen and tender joints (SJC and TJC), 28-joint disease activity scores (DAS28 and DAS28CRP), global disease activity evaluated by the patients and Health Assessment Questionnaire, all obtained at baseline.

RESULTS

Individually, all autoantibodies except immunoglobulin G (IgG) RF associated with low SJC and TJC and with high ESR. In IgM RF-negative patients, ACPA associated strictly with low number of swollen and tender joints. This association persisted in multiple regression and stratified analyses where IgM and IgA RF instead associated with inflammation expressed as ESR. Among subjects without any ACPA peptide reactivity, there was no association between RF isotypes and ESR. The effect of RF on ESR increased with the number of ACPA reactivities, especially for IgM RF. In patients fulfilling the 1987 ACR criteria without taking RF into account, associations between IgM RF and high ESR, as well as between ACPA and low joint counts, remained.

CONCLUSION

Whereas ACPA associate with low counts of affected joints in early RA, RF associates with elevated measures of systemic inflammation in an ACPA-dependent manner. This latter finding corroborates in vitro models of ACPA and RF in immune complex-induced inflammation. These phenotypic associations are independent of classification criteria.

Posttranslational modifications in psoriatic arthritis: A systematic literature review

BACKGROUND AND AIMS

Psoriatic arthritis (PsA) is an inflammatory complex condition. Posttranslational modifications influence almost all aspects of normal cell biology and pathogenesis. The aim of this systematic review was to collect all published evidence regarding posttranslational modifications in PsA, and the main outcome was to evaluate an association between disease outcomes and specific posttranslational modifications in PsA.

METHODS

A systematic electronic search was performed in Medline, PubMed, Cochrane, Virtual Health Library, and Embase databases. A total of 587 articles were identified; 59 were evaluated after removing duplicates and scanning, of which 47 were included. A descriptive analysis was conducted, with results grouped according to the type of posttranslational modification evaluated. The protocol was registered at the PROSPERO database.

RESULTS

Seven posttranslational modifications were identified: citrullination, carbamylation, phosphorylation, glycosylation, acetylation, methylation, and oxidative stress. Anti-citrullinated peptide and anti-carbamylated protein have been evaluated in rheumatoid arthritis. There is now information suggesting that these antibodies may be helpful in improving the diagnosis of PsA and that they may demonstrate a correlation with worse disease progression (erosions, polyarticular involvement, and poor treatment response). Glycosylation was associated with increased inflammation and phosphorylation products related to the expression of SIRT2 and pSTAT3 or the presence of Th17 and cytokine interleukin-22, suggesting a possible therapeutic target.

CONCLUSIONS

Posttranslational modifications often play a key role in modulating protein function in PsA and correlate with disease outcomes. Citrullination, carbamylation, phosphorylation, glycosylation, acetylation, methylation, and oxidative stress were identified as associated with diagnosis and prognosis.

Predicting Inflammatory Arthritis in At-Risk Persons: Development of Scores for Risk Stratification

BACKGROUND

Inflammatory arthritis (IA) is an immune-related condition defined by the presence of clinical synovitis. Its most common form is rheumatoid arthritis.

OBJECTIVE

To develop scores for predicting IA in at-risk persons using multidimensional biomarkers.

DESIGN

Prospective observational cohort study.

SETTING

Single-center, Leeds, United Kingdom.

PARTICIPANTS

Persons with new musculoskeletal symptoms, a positive test result for anticitrullinated protein antibodies, and no clinical synovitis and followed for 48 weeks or more or until IA occurred.

MEASUREMENTS

A simple score was developed using logistic regression, and a comprehensive score was developed using the least absolute shrinkage and selection operator Cox proportional hazards regression. Internal validation with bootstrapping was estimated, and a decision curve analysis was done.

RESULTS

Of 455 participants, 32.5% (148 of 455) developed IA, and 15.4% (70 of 455) developed it within 1 year. The simple score identified 249 low-risk participants with a false negative rate of 5% (and 206 high-risk participants with a false-positive rate of 72%). The comprehensive score identified 119 high-risk participants with a false-positive rate of 29% (and 336 low-risk participants with a false-negative rate of 19%); 40% of high-risk participants developed IA within 1 year and 71% within 5 years.

LIMITATIONS

External validation is required. Recruitment occurred over 13 years, with lower rates of IA in later years. There was geographic variation in laboratory testing and recruitment availability.

CONCLUSION

The simple score identified persons at low risk for IA who were less likely to need secondary care. The comprehensive score identified high-risk persons who could benefit from risk stratification and preventive measures. Both scores may be useful in clinical care and should also be useful in clinical trials.

PRIMARY FUNDING SOURCE

National Institute for Health and Care Research Leeds Biomedical Research Centre.

Prediction of Erosive Disease Development by Antimitochondrial Antibodies in Rheumatoid Arthritis

OBJECTIVE

Mitochondria are found in the extracellular space in rheumatoid arthritis (RA). However, whether mitochondria are a source of autoantigens in RA has not been carefully addressed. Thus, we undertook this study to investigate the presence and significance of antimitochondrial antibodies (AMAs) in patients with RA.

METHODS

AMAs were measured in serum samples from 3 cross-sectional cohorts of RA patients (n = 95, n = 192, and n = 117) and healthy individuals (n = 38, n = 72, and n = 50) using a flow cytometry-based assay. Further, AMAs were detected using an anti-mitofusin-1 (anti-MFN-1) IgG enzyme-linked immunosorbent assay and Western blot analysis. A longitudinal inception cohort, followed up for a median of 8 years, was used to study disease progression.

RESULTS

AMA levels were elevated in RA patients from all 3 cohorts as compared to healthy individuals (P < 0.001, P < 0.05, and P < 0.01), with a range of 14-26% positivity. Levels of anti-MFN-1 antibodies correlated with AMA levels (r = 0.31, P = 0.006) and were elevated in RA patients as compared to healthy individuals (P < 0.001). The presence of AMAs was associated with erosive disease (P < 0.05) and interstitial lung disease (P < 0.01). Further, AMA levels were found to predict erosive disease (odds ratio [OR] 4.59, P = 0.006) and joint space narrowing (OR 3.08, P = 0.02) independent of anti-citrullinated protein antibodies. Finally, anti-MFN-1 antibodies identified seronegative patients developing erosive disease (OR 9.33; P = 0.02).

CONCLUSION

Our findings demonstrate the presence of novel autoantibodies targeting mitochondria in the setting of RA. AMAs were used to stratify patients based on disease phenotype and to predict development of erosive disease, including in patients with seronegative disease. Our results highlight the essential role of mitochondria in the pathogenesis of RA and suggest a possible benefit of therapies targeting mitochondrial-mediated inflammation and clearance in these patients.

Serum Autoantibody Biomarkers for Management of Rheumatoid Arthritis Disease

Rheumatoid arthritis (RA) is a systemic chronic autoimmune inflammatory disease that is characterized by the destruction of bone and production of autoantibodies such as rheumatoid factor (RF) and anticitrullinated protein antibodies (ACPAs). The high prevalence of this disease and the need of affordable tools for its early detection led us to prepare the first electrochemical immunoplatform for the simultaneous determination of four RA biomarkers, the autoantibodies: RF, anti-peptidyl-arginine deiminase enzyme (anti-PAD4), anti-cyclic citrullinated peptide (anti-CCP), and anti-citrullinated vimentin (anti-MCV). Functionalized magnetic beads (MBs) were used to immobilize the specific antigens, and sandwich-type immunoassays were implemented for the amperometric detection of the four autoantibodies, using the horseradish peroxidase (HRP)/H₂O₂/hydroquinone (HQ) system. The immunoplatform was applied to the determination of the biomarkers in human serum of twenty-two patients diagnosed with RA and four healthy individuals, and the results were validated against ELISA tests and the certified values.

[Autoimmune diagnostics in nephrology and rheumatology]

Autoimmune diagnostics plays a central role in the detection of various acute and/or chronic diseases in both nephrology and rheumatology, which are associated with high morbidity and mortality if left untreated or not detected in time. Patients are threatened with significant limitations in everyday skills and quality of life due to loss of kidney function and dialysis, immobilizing and destructive joint processes or also significant damage of organ systems. In all of these autoimmune diseases, early diagnosis and treatment is of central importance for the further course and prognosis of disease.Antibodies play an essential role in the pathogenesis of autoimmune diseases. Antibodies are either directed against organ or tissue-specific antigens, such as in primary membranous glomerulonephritis or Goodpasture's syndrome, or they lead to a systemic disease such as systemic lupus erythematosus (SLE) or rheumatoid arthritis.Knowledge of the sensitivity and specificity of antibodies is crucial for the interpretation of antibody diagnostics results. Antibody detection can precede the clinical onset of the disease, and antibody titers often reflect disease activity. However, there are also false positive results. Detection of antibodies in the absence of disease symptoms often leads to uncertainty and unnecessary further diagnostics. Therefore, an unfounded "antibody screening" is not recommended.A rational antibody diagnostics is an integral part of the diagnostics and during treatment of nephrological and rheumatological diseases like glomerulonephrititis, pulmorenal syndrome, SLE and other collagenosis, thrombotic microangiopathy (HUS/TTP) and rheumatoid arthritis.

The Role of Autoantibody Testing in Modern Personalized Medicine

Personalized medicine (PM) aims individualized approach to prevention, diagnosis, and treatment. Precision Medicine applies the paradigm of PM by defining groups of individuals with akin characteristics. Often the two terms have been used interchangeably. The quest for PM has been advancing for centuries as traditional nosology classification defines groups of clinical conditions with relatively similar prognoses and treatment options. However, any individual is characterized by a unique set of multiple characteristics and therefore the achievement of PM implies the determination of myriad demographic, epidemiological, clinical, laboratory, and imaging parameters. The accelerated identification of numerous biological variables associated with diverse health conditions contributes to the fulfillment of one of the pre-requisites for PM. The advent of multiplex analytical platforms contributes to the determination of thousands of biological parameters using minute amounts of serum or other biological matrixes. Finally, big data analysis and machine learning contribute to the processing and integration of the multiplexed data at the individual level, allowing for the personalized definition of susceptibility, diagnosis, prognosis, prevention, and treatment. Autoantibodies are traditional biomarkers for autoimmune diseases and can contribute to PM in many aspects, including identification of individuals at risk, early diagnosis, disease sub-phenotyping, definition of prognosis, and treatment, as well as monitoring disease activity. Herein we address how autoantibodies can promote PM in autoimmune diseases using the examples of systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, Sjögren syndrome, systemic sclerosis, idiopathic inflammatory myopathies, autoimmune hepatitis, primary biliary cholangitis, and autoimmune neurologic diseases.

Signal inhibitory receptor on leukocytes-1 regulates the formation of the neutrophil extracellular trap in rheumatoid arthritis

BACKGROUND

Neutrophil extracellular trap (NET) has been demonstrated to play important roles in the pathogenesis and progression of rheumatoid arthritis (RA). Emerging evidence indicates that ligation of signal inhibitory receptor on leukocytes-1 (SIRL-1) can dampen Fc receptor-induced reactive oxygen species (ROS) production in primary human neutrophils by reducing extracellular signal-regulated kinase (ERK) activation. The current study aimed to determine the regulatory effects of SIRL-1 on the NET formation and ROS production by comparing RA patients and healthy controls (HC).

METHODS

Multiple assays were employed to detect the expression level of SIRL-1, including immunohistochemical staining, quantitative reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry. Peripheral blood neutrophils from both HC and RA patients were freshly isolated. The NET formation was assessed spontaneously before and after exposure to serum samples from HC and RA patients, respectively. The quantification of NET formation was determined by fluorescence microscopy and Spectra Max M5 fluorescent plate reader. The ROS production was examined by flow cytometry.

RESULTS

The expression level of SIRL-1 in peripheral blood neutrophils was decreased in RA, comparing to HC. The RA-originated neutrophils showed higher levels of ROS production and NET formation. Ligation of SIRL-1 to neutrophils suppressed ROS production and NET formation. Stimulation of neutrophils with severe anti-cyclic citrullinated peptides (CCP) induced NET formation, which could be inhibited by application of SIRL-1 ligation.

CONCLUSION

The current study identified SIRL-1 differentially expressed in neutrophils between RA and HC. Ligation of SIRL-1 inhibited ROS production and NET formation. Downregulation of SIRL-1 showed correlation with upregulation of NET formation in RA. These findings showed the regulation of SIRL-1 on NET formation and provided a potential therapeutic target for RA.

Long noncoding and micro-RNA expression in a model of articular chondrocyte degeneration induced by stromal cell-derived factor-1

Background

Gene regulatory network analysis has found that long noncoding ribonucleic acids (lncRNAs) are strongly associated with the pathogenesis of osteoarthritis.

Objectives

To determine the differential expression of lncRNAs and microRNAs (miRNAs) in normal chondrocytes and those from a model of articular chondrocyte degeneration.

Methods

Chondrocytes were cultured from cartilage obtained from patients diagnosed with osteoarthritis of the knee. Stromal cell-derived factor-1 (SDF-1) was used to induce their degeneration. Total RNA was extracted, analyzed, amplified, labeled, and hybridized on a chip to determine expression. The set of enriched differentially expressed miRNAs was analyzed by gene ontology and the Kyoto Encyclopedia of Genes and Genomes to describe the functional properties of the key biological processes and pathways. We conducted a bioinformatics analysis using Cytoscape to elucidate the interactions between miRNAs and proteins.

Results

We found that the expression of 186 lncRNAs was significantly different in the model of chondrocyte degeneration, in which 88 lncRNAs were upregulated, and 98 were downregulated. Expression of 684 miRNAs was significantly different. Analysis of the protein-protein interaction (PPI) network indicated that the genes for CXCL10, ISG15, MYC, MX1, OASL, IFIT1, RSAD2, MX2, IFI44L, and BST2 are the top 10 core genes, identifying the most important functional modules to elucidate the differential expression of miRNAs.

Conclusions

These data may provide new insights into the molecular mechanisms of chondrocyte degeneration in osteoarthritis, and the identification of lncRNAs and miRNAs may provide potential targets for the differential diagnosis and therapy of osteoarthritis.

The Clinical Impact of Seropositivity on Treatment Response in Patients with Rheumatoid Arthritis Treated with Etanercept: A Real-World Iraqi Experience

Purpose

To assess the clinical impact of rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA)’s seropositivity on treatment response in patients with rheumatoid arthritis (RA) treated with etanercept.

Patients and Methods

A retrospective analysis of patients with RA registered in Baghdad Teaching Hospital Registry from May 2012 to August 2019 was conducted. Patients aged ≥18 years, meeting the ACR/EULAR 2010 criteria for RA, being treated with etanercept, and followed up at ≥1 year after etanercept initiation were included; patients who received any other biologics for RA were excluded. Patients were classified as seropositive (RF- and ACPA-positive), seronegative (RF- and ACPA-negative), RF-positive, RF-negative, ACPA-positive, and ACPA-negative. The primary outcomes included Clinical Disease Activity Index (CDAI) and Disease Activity Score 28 (DAS28) which were measured at one year after treatment initiation.

Results

At baseline, a total of 1318 (88.3%) patients were seropositive; 1122 (75.2%) and 1054 (70.6%) patients were RF- and ACPA-positive, respectively. Baseline mean CDAI scores were significantly (P = 0.001) higher among seropositive patients compared with seronegative patients. The baseline mean DAS28 score was also significantly higher in ACPA-positive group compared with the ACPA-negative group (P = 0.021). At baseline, the number of patients who had high CDAI scores was significantly higher among the seropositive, RF-positive, and ACPA-positive groups (P = 0.001, P = 0.001, and P = 0.002, respectively). After one year of treatment with etanercept, among seropositive versus seronegative and ACPA-positive versus ACPA-negative groups, there was a significant improvement in terms of the mean CDAI score (P = 0.004 and P = 0.017, respectively) and CDAI response (P = 0.011 and P = 0.048, respectively). At one year, the proportion of patients among the seropositive versus seronegative group who reached remission were 566 (42.9%) versus 78 (44.6%) and 642 (47.3%) versus 83 (47.4%), for CDAI and DAS28 response, respectively.

Conclusion

The results imply that seropositivity and ACPA-positivity may influence the treatment response in patients with RA, who were treated with etanercept.

Molecular Dynamics Study of Citrullinated Proteins Associated with the Development of Rheumatoid Arthritis

Biological activity regulation by protein post-translational modification (PTM) is critical for cell function, development, differentiation, and survival. Dysregulation of PTM proteins is present in various pathological conditions, including rheumatoid arthritis (RA). RA is a systemic autoimmune disease that primarily affects joints, and there are three main types of protein PTMs associated with the development of this disease, namely, glycosylation, citrullination, and carbamylation. Glycosylation is important for the processing and presentation of antigen fragments on the cell surface and can modulate immunoglobulin activity. The citrullination of autoantigens is closely associated with RA, as evidenced by the presence of antibodies specific to citrullinated proteins in the serum of patients. Carbamylation and dysregulation have recently been associated with RA development in humans.In this study, we performed an overview analysis of proteins with post-translational modifications associated with the development of RA adverted in peer-reviewed scientific papers for the past 20 years. As a result of the search, a list of target proteins and corresponding amino acid sequences with PTM in RA was formed. Structural characteristics of the listed modified proteins were extracted from the Protein Data Bank. Then, molecular dynamics experiments of intact protein structures and corresponding structures with PTMs were performed regarding structures in the list announced in the ProtDB service. This study aimed to conduct a molecular dynamics study of intact proteins and proteins, including post-translational modification and protein citrullination, likely associated with RA development. We observed another exhibition of the fundamental physics concept, symmetry, at the submolecular level, unveiled as the autonomous repetitions of outside the protein structural motif performance globule corresponding to those in the whole protein molecule.

Anti-citrullinated Protein Antibody Generation, Pathogenesis, Clinical Application, and Prospects

Anti-citrullinated protein antibodies (ACPAs) are autoantibodies commonly observed in patients with rheumatoid arthritis (RA). Currently, most of the mechanisms of ACPA formation and bone destruction are well-understood, however, some unknown mechanisms still exist. There have been many new advances in ACPA-related clinical applications and targeted therapies. However, the existence of different ACPA subtypes is a limitation of targeted therapy. Herein, we present an overview of the process of ACPA generation, the underlying pathogenesis, and relevant clinical application and prospects.

Peptides Bearing Multiple Post-Translational Modifications as Antigenic Targets for Severe Rheumatoid Arthritis Patients

Rheumatoid arthritis (RA) is characterized by the presence of autoantibodies that are of paramount importance for the diagnosis and prognosis of the disease and have been implicated in its pathogenesis. Proteins resulting from post-translational modifications (PTMs) are capable of triggering autoimmune responses important for the development of RA. In this work, we investigate serum antibody reactivity in patients with an established RA against a panel of chimeric peptides derived from fibrin and filaggrin proteins and bearing from one to three PTMs (citrullination, carbamylation and acetylation) by home-designed ELISA tests (anti-AMPA autoantibodies). The role of anti-AMPAs as biomarkers linked to the presence of a more severe RA phenotype (erosive disease with radiological structural damage) and to the presence of interstitial lung disease (ILD), a severe extra-articular manifestation in RA patients entailing a high mortality, was also analyzed. In general, the association with the clinical phenotype of RA was confirmed with the different autoantibodies, and especially for IgA and IgM isotypes. The prevalence of severe joint damage was only statistically significant for the IgG isotype when working with the peptide bearing three PTMs. Furthermore, the median titers were significantly higher in patients with RA-ILD, a finding not observed for the IgG isotype when working with the single- and double-modified peptides.

Peptidylarginine Deiminase 2 in Host Immunity: Current Insights and Perspectives

Peptidylarginine deiminases (PADs) are a group of enzymes that catalyze post-translational modifications of proteins by converting arginine residues into citrullines. Among the five members of the PAD family, PAD2 and PAD4 are the most frequently studied because of their abundant expression in immune cells. An increasing number of studies have identified PAD2 as an essential factor in the pathogenesis of many diseases. The successes of preclinical research targeting PAD2 highlights the therapeutic potential of PAD2 inhibition, particularly in sepsis and autoimmune diseases. However, the underlying mechanisms by which PAD2 mediates host immunity remain largely unknown. In this review, we will discuss the role of PAD2 in different types of cell death signaling pathways and the related immune disorders contrasted with functions of PAD4, providing novel therapeutic strategies for PAD2-associated pathology.

Identification of a Novel Serological Marker in Seronegative Rheumatoid Arthritis Using the Peptide Library Approach

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation mainly affecting the joints leading to cartilage and bone destruction. The definition of seropositive or seronegative RA is based on the presence or absence of rheumatoid factor (RF) and anti-citrullinated peptide antibodies (ACPAs). Other autoantibodies have been identified in the last decade such as antibodies directed against carbamylated antigens, peptidyl-arginine deiminase type 4 and v-Raf murine sarcoma viral oncogene homologue B. In order to identify relevant autoantigens, we screened a random peptide library (RPL) with pooled IgGs obtained from 50 patients with seronegative RA. Patients’ sera were then used in an ELISA test to identify the most frequently recognized peptide among those obtained by screening the RPL. Sera from age- and sex-matched healthy subjects were used as controls. We identified a specific peptide (RA-peptide) recognized by RA patients’ sera, but not by healthy subjects or by patients with other immune-mediated diseases. The majority of sera from seronegative and seropositive RA patients (73.8% and 63.6% respectively) contained IgG antibodies directed against the RA-peptide. Interestingly, this peptide shares homology with some self-antigens, such as Protein-tyrosine kinase 2 beta, B cell scaffold protein, Liprin-alfa1 and Cytotoxic T lymphocyte protein 4. Affinity purified anti-RA-peptide antibodies were able to cross react with these autoantigens. In conclusion, we identified a peptide that is recognized by seropositive and, most importantly, by seronegative RA patients’ sera, but not by healthy subjects, conferring to this epitope a high degree of specificity. This peptide shares also homology with other autoantigens which can be recognized by autoantibodies present in seronegative RA sera. These newly identified autoantibodies, although present also in a percentage of seropositive RA patients, may be considered as novel serum biomarkers for seronegative RA, which lacks the presence of RF and/or ACPAs.

Treatment journey in rheumatoid arthritis with biosimilars: from better access to good disease control through cost savings and prevention of nocebo effects

Early diagnosis and treatment of rheumatoid arthritis (RA) are of critical importance to halt the progression of the disease. Optimal use of advanced imaging techniques or biomarkers may facilitate early diagnosis of RA. Even though many disease-modifying anti-rheumatic drugs (DMARDs) are available for RA treatment, biological DMARDs (bDMARDs) offer expanding therapeutic options and good outcomes in patients with RA who do not have a sufficient response to conventional synthetic DMARDs. However, high costs of bDMARDs have limited patient access to optimised disease management and increased the cost burden for healthcare systems. The advent of biosimilars led to significant cost savings driven by price competition among the reference products, which could be beneficial for healthcare systems. Healthcare provider (HCP)–patient communication and informed shared decision-making are crucial to prevent the occurrence of a nocebo effect, which results from negative perceptions that patients may have and could lead to less effective outcomes. Research has demonstrated that effective communication between HCPs and patients utilising positive framing can improve acceptance by patients to be initiated on or switched to a biosimilar and can help to integrate biosimilars into routine clinical practice to maximise benefits for patients with RA.

PADI2 Polymorphisms Are Significantly Associated With Rheumatoid Arthritis, Autoantibodies Serologic Status and Joint Damage in Women from Southern Mexico

The enzymes of the family peptidylarginine deiminases (PADs) have an important role in the pathogenesis of rheumatoid arthritis (RA) due to their association with the anti-citrullinated protein antibodies (ACPA) production. To evaluate the association between single-nucleotide polymorphisms (SNPs) in the PADI2 gene and RA susceptibility, related clinical parameters, and the serologic status of autoantibodies in a women population with RA from southern Mexico, a case-control study was conducted (case n=229; control n=333). Sociodemographic characteristics were evaluated, along with clinical parameters, inflammation markers, the levels of ACPAs as anti-cyclic citrullinated peptides (anti-CCPs), anti-modified citrullinated vimentin (anti-MCV), and rheumatoid factor (RF). Genomic DNA was extracted from peripheral blood, and three SNPs of the PADI2 gene (rs1005753, rs2057094, and rs2235926) were performed by qPCR using TaqMan probes. The data analysis reveals that the carriers of the T allele for rs2057094 and rs2235926 presented an earlier onset of the disease (β= -3.26; p = 0.03 and β = -4.13; p = 0.015, respectively) while the carriers of the T allele for rs1005753 presented higher levels of anti-CCPs (β= 68.3; p = 0.015). Additionally, the T allele of rs2235926 was associated with a positive RF (OR = 2.90; p = 0.04), anti-MCV (OR = 2.92; p = 0.05), and with the serologic status anti-CCP+/anti-MCV+ (OR = 3.02; p = 0.03), and anti-CCP+/anti-MCV+/RF+ (OR = 3.79; p = 0.004). The haplotypes GTT (OR =1.52; p = 0.027) and TTT (OR = 1.32; p = 0.025) were associated with the presence of RA. In addition, in this study the haplotype TTT is linked to the presence of radiographic joint damage defined by a Sharp-van der Heijde score (SHS) ≥2 (OR = 1.97; p = 0.0021) and SHS ≥3 (OR = 1.94; p = 0.011). The haplotype TTT of SNPs rs1005753, rs2057094, and rs2235926 of the PADI2 gene confers genetic susceptibility to RA and radiographic joint damage in women from southern Mexico. The evidence reveals that SNPs of the PADI2 gene favors the presence of a positive serologic status in multiple autoantibodies and the clinical manifestations of RA at an early onset age.

Intensive therapy for moderate established rheumatoid arthritis: the TITRATE research programme

Background

Rheumatoid arthritis is a major inflammatory disorder and causes substantial disability. Treatment goals span minimising disease activity, achieving remission and decreasing disability. In active rheumatoid arthritis, intensive management achieves these goals. As many patients with established rheumatoid arthritis have moderate disease activity, the TITRATE (Treatment Intensities and Targets in Rheumatoid Arthritis ThErapy) programme assessed the benefits of intensive management.

Objectives

To (1) define how to deliver intensive therapy in moderate established rheumatoid arthritis; (2) establish its clinical effectiveness and cost-effectiveness in a trial; and (3) evaluate evidence supporting intensive management in observational studies and completed trials.

Design

Observational studies, secondary analyses of completed trials and systematic reviews assessed existing evidence about intensive management. Qualitative research, patient workshops and systematic reviews defined how to deliver it. The trial assessed its clinical effectiveness and cost-effectiveness in moderate established rheumatoid arthritis.

Setting

Observational studies (in three London centres) involved 3167 patients. These were supplemented by secondary analyses of three previously completed trials (in centres across all English regions), involving 668 patients. Qualitative studies assessed expectations (nine patients in four London centres) and experiences of intensive management (15 patients in 10 centres across England). The main clinical trial enrolled 335 patients with diverse socioeconomic deprivation and ethnicity (in 39 centres across all English regions).

Participants

Patients with established moderately active rheumatoid arthritis receiving conventional disease-modifying drugs.

Interventions

Intensive management used combinations of conventional disease-modifying drugs, biologics (particularly tumour necrosis factor inhibitors) and depot steroid injections; nurses saw patients monthly, adjusted treatment and provided supportive person-centred psychoeducation. Control patients received standard care.

Main outcome measures

Disease Activity Score for 28 joints based on the erythrocyte sedimentation rate (DAS28-ESR)-categorised patients (active to remission). Remission (DAS28-ESR < 2.60) was the treatment target. Other outcomes included fatigue (measured on a 100-mm visual analogue scale), disability (as measured on the Health Assessment Questionnaire), harms and resource use for economic assessments.

Results

Evaluation of existing evidence for intensive rheumatoid arthritis management showed the following. First, in observational studies, DAS28-ESR scores decreased over 10–20 years, whereas remissions and treatment intensities increased. Second, in systematic reviews of published trials, all intensive management strategies increased remissions. Finally, patients with high disability scores had fewer remissions. Qualitative studies of rheumatoid arthritis patients, workshops and systematic reviews helped develop an intensive management pathway. A 2-day training session for rheumatology practitioners explained its use, including motivational interviewing techniques and patient handbooks. The trial screened 459 patients and randomised 335 patients (168 patients received intensive management and 167 patients received standard care). A total of 303 patients provided 12-month outcome data. Intention-to-treat analysis showed intensive management increased DAS28-ESR 12-month remissions, compared with standard care (32% vs. 18%, odds ratio 2.17, 95% confidence interval 1.28 to 3.68; p = 0.004), and reduced fatigue [mean difference –18, 95% confidence interval –24 to –11 (scale 0–100); p < 0.001]. Disability (as measured on the Health Assessment Questionnaire) decreased when intensive management patients achieved remission (difference –0.40, 95% confidence interval –0.57 to –0.22) and these differences were considered clinically relevant. However, in all intensive management patients reductions in the Health Assessment Questionnaire scores were less marked (difference –0.1, 95% confidence interval –0.2 to 0.0). The numbers of serious adverse events (intensive management n = 15 vs. standard care n = 11) and other adverse events (intensive management n = 114 vs. standard care n = 151) were similar. Economic analysis showed that the base-case incremental cost-effectiveness ratio was £43,972 from NHS and Personal Social Services cost perspectives. The probability of meeting a willingness-to-pay threshold of £30,000 was 17%. The incremental cost-effectiveness ratio decreased to £29,363 after including patients’ personal costs and lost working time, corresponding to a 50% probability that intensive management is cost-effective at English willingness-to-pay thresholds. Analysing trial baseline predictors showed that remission predictors comprised baseline DAS28-ESR, disability scores and body mass index. A 6-month extension study (involving 95 intensive management patients) showed fewer remissions by 18 months, although more sustained remissions were more likley to persist. Qualitative research in trial completers showed that intensive management was acceptable and treatment support from specialist nurses was beneficial.

Limitations

The main limitations comprised (1) using single time point remissions rather than sustained responses, (2) uncertainty about benefits of different aspects of intensive management and differences in its delivery across centres, (3) doubts about optimal treatment of patients unresponsive to intensive management and (4) the lack of formal international definitions of ‘intensive management’.

Conclusion

The benefits of intensive management need to be set against its additional costs. These were relatively high. Not all patients benefited. Patients with high pretreatment physical disability or who were substantially overweight usually did not achieve remission.

Future work

Further research should (1) identify the most effective components of the intervention, (2) consider its most cost-effective delivery and (3) identify alternative strategies for patients not responding to intensive management.

Trial registration

Current Controlled Trials ISRCTN70160382.

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 9, No. 8. See the NIHR Journals Library website for further project information.

Osteoblast role in the pathogenesis of rheumatoid arthritis

In the pathogenesis of several rheumatic diseases, such as rheumatoid arthritis, spondyloarthritis, osteoarthritis, osteoporosis, alterations in osteoblast growth, differentiation and activity play a role. In particular, in rheumatoid arthritis bone homeostasis is perturbed: in addition to stimulating the pathologic bone resorption process performed by osteoclasts in course of rheumatoid arthritis, proinflammatory cytokines (such as Tumor Necrosis factor-α, Interleukin-1) can also inhibit osteoblast differentiation and function, resulting in net bone loss. Mouse models of rheumatoid arthritis showed that complete resolution of inflammation (with maximal reduction in the expression of pro-inflammatory factors) is crucial for bone healing, performed by osteoblasts activity. In fact, abnormal activity of factors and systems involved in osteoblast function in these patients has been described. A better understanding of the pathogenic mechanisms involved in osteoblast dysregulation could contribute to explain the generalized and focal articular bone loss found in rheumatoid arthritis. Nevertheless, these aspects have not been frequently and directly evaluated in studies. This review article is focused on analysis of the current knowledge about the role of osteoblast dysregulation occurring in rheumatoid arthritis: a better knowledge of these mechanisms could contribute to the realization of new therapeutic strategies.

Mitochondrial N-formyl methionine peptides associate with disease activity as well as contribute to neutrophil activation in patients with rheumatoid arthritis

OBJECTIVES

Literature suggests that neutrophils of patients with rheumatoid arthritis (RA) are primed to respond to N-formyl methionine group (formylated peptides). Animal models indicate that formylated peptides contribute to joint damage via neutrophil recruitment and inflammation in joints. Non-steroidal anti-inflammatory drugs are also known to inhibit formyl peptide-induced neutrophil activation. The predominant source of formylated peptides in sterile inflammatory conditions like RA is mitochondria, organelles with prokaryotic molecular signatures. However, there is no direct evidence of mitochondrial formyl peptides (mtNFPs) in the circulation of patients with RA and their potential role in neutrophil-mediated inflammation in RA, including their clinical significance.

METHODS

Levels of mtNFPs (total fMet, MT-ND6) were analyzed using ELISA in plasma and serum obtained from patients in 3 cross-sectional RA cohorts (n = 275), a longitudinal inception cohort (n = 192) followed for a median of 8 years, and age/gender-matched healthy controls (total n = 134). Neutrophil activation assays were done in the absence or presence of formyl peptide receptor 1 (FPR1) inhibitor cyclosporine H.

RESULTS

Elevated levels of total fMet were observed in the circulation of patients with RA as compared to healthy controls (p < 0.0001) associating with disease activity and could distinguish patients with the active disease from patients with inactive disease or patients in remission. Baseline levels of total fMet correlated with current and future joint involvement, respectively and predicted the development of rheumatoid nodules (OR = 1.2, p = 0.04). Further, total fMet levels improved the prognostic ability of ACPA in predicting erosive disease (OR of 7.9, p = 0.001). Total fMet levels correlated with markers of inflammation and neutrophil activation. Circulating mtNFPs induced neutrophil activation in vitro through FPR1-dependent mechanisms.

CONCLUSIONS

Circulating mtNFPs could be novel biomarkers of disease monitoring and prognosis for RA and in investigating neutrophil-mediated inflammation in RA. We propose, FPR1 as a novel therapeutic target for RA.

Outcomes in rheumatoid arthritis patients treated with abatacept: a UK multi-centre observational study

BACKGROUND

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease that causes chronic synovitis, resulting in progressive joint destruction and functional disability and affects approximately 400,000 people in the UK. This real-world study aimed to describe the characteristics, treatment patterns and clinical outcomes of patients who received abatacept in UK clinical practice.

METHODS

This was a multi-centre, retrospective, observational study of patients with RA treated with abatacept at four UK centres between 01 January 2013 and 31 December 2017. Data were collected from medical records of each patient from the index date (date of first bDMARD initiation) until the most recent visit, death or end of study (31 December 2017).

RESULTS

In total, 213 patients were included in the study. Patients received up to eight lines of therapy (LOTs). Treatment with abatacept, or any other bDMARD, was associated with reductions in DAS28-ESR and DAS28-CRP scores at 6 and 12 months. The distribution of EULAR responses (good/moderate/no response) tended to be more favourable for patients when receiving abatacept than when receiving other bDMARDs (22.8%/41.3%/35.9% versus 16.6%/41.4%/42.1% at 6 months, and 27.9%/36.1%/36.1% versus 21.2%/34.5%/44.2% at 12 months). Patients receiving abatacept at LOT1 (n = 68) spent significantly longer on treatment compared with patients receiving other bDMARDs (53.4 vs. 17.4 months; p< 0.01); a similar trend was observed for LOT2. Among patients who discontinued after 6 months, a greater proportion experienced infection requiring antibiotics when receiving other bDMARDs compared to those receiving abatacept.

CONCLUSIONS

RA patients who received bDMARDs, including abatacept, experienced reduced disease activity. When receiving abatacept as first or second line of therapy, patients persisted with treatment significantly longer than those receiving other bDMARDs.

CTRP9 protects against MIA-induced inflammation and knee cartilage damage by deactivating the MAPK/NF-κB pathway in rats with osteoarthritis

C1q/TNF-related protein 9 (CTRP9), the closest paralog of adiponectin, has been reported to protect against inflammation-related diseases. However, its role in regulating osteoarthritis (OA) has not been fully elucidated. First, a rat model of OA was generated. Furthermore, rats with OA were injected with different doses of recombinant CTRP9 protein (rCTRP9), and the knee cartilage damage was evaluated. Finally, the phosphorylation of p38 and the secretion of matrix metalloproteinases (MMPs) were detected by Western blotting and enzyme-linked immunosorbent assay. Results revealed that CTRP9 was highly expressed in adipose tissue, followed by skeletal muscle and cartilage tissue, and less expressed in liver, kidney and lung. Moreover, the expression of CTRP9 significantly decreased in the monosodium iodoacetate (MIA) group in the knee cartilage and knee synovial fluid, and the contents of interleukin-1β (IL-1β) and IL-6 significantly increased in knee synovial fluid. In addition, rCTRP9 alleviated MIA-induced inflammation, oxidative stress and knee cartilage damage in a dose-dependent way. In addition, rCTRP9 could attenuate the expression of p38MAPK and p-p38 and suppress the expression of nuclear factor-kappa B (NF-κB), p65 and MMPs. Collectively, the results of the present study suggested that CTRP9 alleviates the inflammation of MIA-induced OA through deactivating p38MAPK and NF-κB signaling pathways in rats.

Clinical Utility and Cost Savings in Predicting Inadequate Response to Anti-TNF Therapies in Rheumatoid Arthritis

INTRODUCTION

The PrismRA® test identifies rheumatoid arthritis (RA) patients who are unlikely to respond to anti-tumor necrosis factor (anti-TNF) therapies. This study evaluated the clinical and financial outcomes of incorporating PrismRA into routine clinical care of RA patients.

METHODS

A decision-analytic model was created to evaluate clinical and economic outcomes in the 12-month period following first biologic treatment. Two treatment strategies were compared: (1) observed clinical decision-making based on a 175-patient cohort receiving an anti-TNF therapy as their first biologic after failure of conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and (2) modeled clinical decision-making of the same population using PrismRA results to inform first-line biologic treatment choice. Modeled costs include biologic drug pharmacy, non-biologic pharmacy, and total medical costs. The odds of inadequate response to anti-TNF therapies and various components of patient care were calculated based on PrismRA results.

RESULTS

Identifying predicted inadequate responders to anti-TNF therapies resulted in a modeled 38% increase in ACR50 response to first-line biologic therapies. The fraction of patients who achieved an ACR50 response to any therapy (TNFi and others) within the 12-month period was 33% higher in the PrismRA-stratified population than in the unstratified population (59 vs. 44%, respectively). When therapy prescriptions were modeled according to PrismRA results, cost savings were modeled for all financial variables: overall costs (4% decreased total, 19% decreased on ineffective treatments), total biologic drug pharmacy (4% total, 23% ineffective), non-biologic pharmacy (2% total, 19% ineffective), and medical costs (6% total, 19% ineffective). Female sex was the clinical metric that showed the greatest association with inadequate response to anti-TNF therapies (odds ratio 2.42, 95% confidence interval 1.20, 4.88).

CONCLUSIONS

If PrismRA is implemented into routine clinical care as modeled, predicting which RA patients will have an inadequate response to anti-TNF therapies could save > $7 million in overall ineffective healthcare costs per 1000 patients tested and increase targeted DMARD response rates in RA.

Risk factors for cervical spine instability in patients with rheumatoid arthritis

INTRODUCTION

Cervical spine (C-spine) instability is a unique and significant characteristic of rheumatoid arthritis (RA) because its occurrence is not rare and it can cause compressive cervical myelopathy, which may lead to serious neurologic sequelae. This study evaluated the prevalence and risk factors of C-spine instabilities in RA patients with a focus on anti-citrullinated protein antibody (ACPA) and biologic disease-modifying antirheumatic drug (DMARD) therapies.

METHODS

The presence of C-spine instabilities in 1114 patients with RA was evaluated using C-spine radiographies according to the defined metrics. Multivariable logistic regression analyses were performed to identify independent predictors of C-spine instability. The initiation of biologic DMARDs was assessed via a Kaplan-Meier analysis and compared using log-rank tests.

RESULTS

In total, 306 (27.5%) patients presented with C-spine instabilities. The most common type was atlantoaxial subluxation (AAS; n = 199 [17.9%]). Male sex, positivity for rheumatoid factor and ACPA, erosive change in the peripheral joints, and presence of osteoporosis were independently associated with C-spine instabilities (all P < 0.05). In particular, positivity for ACPA was the most powerful risk factor (odds ratio: 2.33 [95% confidence interval: 1.37, 3.96], P = 0.002), and it was closely associated with AAS. Patients with AAS were at a higher risk for early initiation of biologic DMARDs.

CONCLUSIONS

Positivity for ACPA was a significant risk factor for C-spine instability, and AAS was remarkably correlated to the early initiation of biologic DMARDs, a surrogate index of poor long-term outcomes. Key Points • The presence of antibodies against citrullinated proteins was a strong risk factor for C-spine instability in patients with rheumatoid arthritis. • Atlantoaxial subluxation was significantly associated with early initiation of biologic DMARDs, a surrogate index of poor long-term outcome.

A Neutrophil Activation Biomarker Panel in Prognosis and Monitoring of Patients With Rheumatoid Arthritis

OBJECTIVE

Exaggerated neutrophil activation and formation of neutrophil extracellular traps (NETs) are linked to inflammation and autoimmunity, including rheumatoid arthritis (RA). However, whether NETs are present in the circulation of RA patients and contribute to inflammation and disease progression has not been carefully addressed. We undertook this study to assess markers of neutrophil activation and NET formation in plasma samples, investigating whether they add clinical value in improving the determination of prognosis and monitoring in RA patients.

METHODS

Markers of neutrophil activation (calprotectin) and cell death (NETs) were analyzed, using enzyme-linked immunosorbent assay, in serum and plasma obtained from patients in 3 cross-sectional RA cohorts and sex-matched healthy controls. A longitudinal inception cohort (n = 247), seen for a median follow-up of 8 years, was used for predictive analyses.

RESULTS

Markers of neutrophil activation and cell death were increased in RA patients compared to healthy individuals (P < 0.0001). Calprotectin levels correlated with the Clinical Disease Activity Index (r = 0.53, P < 0.0001) and could be used to distinguish between patients with disease in remission and those with active disease, an observation not seen when examining C-reactive protein levels. A biomarker panel consisting of anti-citrullinated protein antibody and calprotectin could predict erosive disease (odds ratio [OR] 7.5, P < 0.0001) and joint space narrowing (OR 4.9, P = 0.001). NET levels were associated with markers of inflammation (P = 0.0002). Furthermore, NETs and a "neutrophil activation signature" biomarker panel had good predictive value in identifying patients who were developing extraarticular nodules (OR 5.6, P = 0.006).

CONCLUSION

Neutrophils undergo marked activation and cell death in RA. Neutrophil biomarkers can provide added clinical value in the monitoring and prognosis of RA patients and may allow for early preventive treatment intervention.

ACPA-positive versus ACPA-negative rheumatoid arthritis: two distinct erosive disease entities on radiography and ultrasonography

The objective of this study is to assess the prevalence, localization, and severity of bone erosions on radiography (RX) and ultrasonography (US) according to ACPA status in patients with rheumatoid arthritis (RA). 78 patients with ACPA-positive (ACPA+) RA and 30 patients with ACPA-negative (ACPA-) RA fulfilling the ACR 1987 and/or ACR/EULAR 2010 criteria were consecutively included. On RX, a modified Sharp erosion score (SHSe) was evaluated by two blinded readers and one adjudicator for discordant cases (number of eroded joints ≤ three). On US, erosions were scored on six bilateral joints (MCP2, 3, 5; MTP2, 3, 5) with a four-point scale to calculate the total US score for erosions (USSe). The mean total SHSe and USSe were 3.7 and 4.4 times higher in the ACPA+ group than in the ACPA- group, respectively (P < 0.001). On both RX and US, the most discriminating joint between the two groups was MTP5, especially in cases with bilateral erosion. Based on multivariate analyses, ACPA + status was associated with erosive RA on RX according to the EULAR 2013 definition criteria [OR 4.4 (95% CI 1.2-16.4)], and on US according to the following two definitions: the presence of at least two eroded joint facets [OR 3.7 (95% CI 1.4-9.9)] or at least one grade 2 joint facet erosion [OR 9.0 (95% CI 2.8-28.4)]. Compared to ACPA- RA, ACPA + RA is associated independently with more severe erosive disease on RX and US. Both US and RX bilateral erosions in MTP5 joints are highly discriminant for ACPA + RA patients (97.8% in US and 100% in RX).

Tobacco-Derived Lipopolysaccharide, Not Microbial Translocation, as a Potential Contributor to the Pathogenesis of Rheumatoid Arthritis

Microbial lipopolysaccharides (LPS) have been implicated in the pathogenesis of rheumatoid arthritis (RA), possibly driving a systemic inflammatory response that may trigger the development and/or exacerbation of the disease. To explore the existence of this mechanism in African RA patients, we have measured systemic levels of LPS and its surrogate, LPS-binding protein (LBP), as well as those of intestinal fatty acid-binding protein (I-FABP), pulmonary surfactant protein D (SP-D), and cotinine in serum to identify possible origins of LPS, as well as associations of these biomarkers with rheumatoid factor (RF) and anticitrullinated peptide (aCCP) autoantibodies and the DAS 28-3 clinical disease severity score. A cohort of 40 disease-modifying antirheumatic drug-naïve, black South African RA patients rated by compound disease scores and 20 healthy subjects and 10 patients with chronic obstructive pulmonary disease (COPD) as controls were included in this study. Levels of the various biomarkers and autoantibodies were measured using a combination of ELISA and immunofluorimetric and immunoturbidometric procedures. LPS levels were lowest in the RA group compared to the healthy controls (p = 0.026) and COPD patients (p = 0.017), while LBP levels were also significantly lower in RA compared to the healthy individuals (p = 0.036). Levels of I-FABP and SP-D were comparable between all three groups. Categorisation of RA patients according to tobacco usage revealed the following significant positive correlations: LBP with C-reactive protein (p = 0.0137); a trend (p = 0.073) towards an association of LBP with the DAS 28-3 disease severity score; RF-IgG antibodies with both LPS and LBP (p = 0.033 and p = 0.041, respectively); aCCP-IgG antibodies with LPS (p = 0.044); and aCCP-IgG with RF-IgM autoantibodies (p = 0.0016). The findings of this study, several of them novel, imply that tobacco products, as opposed to microbial translocation, represent a potential source of LPS in this study cohort of RA patients, again underscoring the risks posed by tobacco usage for the development and severity of RA.

Inhibition of Long Non-coding RNA CTD-2574D22.4 Alleviates LPS-induced Apoptosis and Inflammatory Injury of Chondrocytes

Background:

Osteoarthritis (OA) is a common joint disease characterized by cartilage degeneration. Long non-coding RNAs (lncRNAs) have been associated with inflammatory diseases, including OA. Here, we investigated the potential molecular role of lncRNAs in OA pathogenesis.

Methods:

ATDC5 cells were treated with lipopolysaccharides (LPS), and qPCR was used to identify and determine expression of potential lncRNAs involved in LPS-induced chondrocyte injury. Cell viability, apoptosis, and expression of cartilage-related genes and inflammatory cytokines were assessed after CTD-2574D22.4 knockdown.

Results:

After LPS stimulation, CTD-2574D22.4 was found to be the second highest up-regulated gene, and the enhanced expression was validated in OA chondrocytes. Moreover, CTD-2574D22.4 inhibition significantly rescued cell viability, suppressed by LPS stress, and markedly attenuated LPS-induced apoptosis. The expression of cartilage-degrading enzymes MMP-13 and ADAMTS-5 were increased, while type II collagen was reduced after LPS treatment. This trend was largely reversed by CTD-2574D22.4 knockdown. Additionally, mRNA and protein levels of key inflammatory cytokines (TNF-a, IL-6, and IL-1β) were significantly elevated in the LPS group and partially relieved upon CTD-2574D22.4 knockdown.

Conclusion:

CTD2574D22.4 knockdown ameliorates LPS-induced cartilage injury by protecting chondrocytes from apoptosis via anti-inflammation and anti- cartilage-degrading pathways. Thus, CTD2574D22.4 might be a potential diagnostic and therapeutic target for OA.

LncRNA SNHG1 alleviates IL-1β-induced osteoarthritis by inhibiting miR-16-5p-mediated p38 MAPK and NF-κB signaling pathways

Long non-coding RNA (LncRNA) small nucleolar RNA host gene 1 (SNHG1) has been reported in the occurrence and development of several diseases, but its biological role and mechanism in osteoarthritis (OA) remain to be illuminated. In the present research, we aimed to investigate the effect of SNHG1 on IL-1β-induced OA and its molecular mechanism. Results revealed that SNHG1 decreased the expression of MMPs, ADAMTs, collagen, and aggrecan, and ameliorates IL-1β-induced metabolic dysfunction in normal human chondrocytes-keen. In addition, SNHG1 inhibited the expressions of pro-inflammatory cytokines in chondrocytes, including NO, PGE2, IL-6, TNF-α, i-NOS, and COX-2. Furthermore, luciferase reporter assay demonstrated that SNHG1 could directly interact with miR-16-5p and suppressed miR-16-5p expression and activity. What is more, miR-16-5p overexpression reversed SNHG1-inhibited aberrant catabolism and inflammation triggered by IL-1β stimulation. Finally, SNHG1 inhibits the expression of miR-16-5p-mediated factors involved in p38MAPK and NF-κB signaling pathways, including ERK1/2, p-p38 and p-p65. Taken together, the results of our studies illuminate that SNHG1 alleviates the inflammation of IL-1β-induced OA through the activation of miR-16-5p-mediated p38MAPK and NF-κB signaling pathway. It suggested that SNHG1 may serve as a potential target for OA diagnosis and treatment.

Cytokines (IL-15, IL-21, and IFN-γ) in rheumatoid arthritis: association with positivity to autoantibodies (RF, anti-CCP, anti-MCV, and anti-PADI4) and clinical activity

INTRODUCTION

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial membrane damage and autoantibody production. RA is a heterogeneous disease, where cytokines such as IL-15, IL-21, and IFN-γ have been associated. However, their association with the autoantibodies has not been clearly described. The aim of this study was to evaluate the relationship between the cytokines IL-15, IL-21, and IFN-γ with the autoantibodies (RF, anti-CCP, anti-MCV, and anti-PADI4) in RA and disease activity.

METHODOLOGY

This study included 153 RA patients and 80 control subjects (CS). The levels of IL-15, IL-21, IFN-γ, anti-CCP, anti-MCV, and anti-PADI4 were quantified by ELISA, whereas RF was quantified by turbidimetry. The disease activity was evaluated by the indices disease activity score 28-erythrocyte sedimentation rate (DAS28-ESR), clinical disease activity index (CDAI), and simple disease activity index (SDAI).

RESULTS

The serum levels of IL-15, IL-21, and IFN-γ, and autoantibodies were increased in RA patients, compared with CS (p < 0.05). A correlation was found between IL-21 and anti-CCP and anti-MCV (p < 0.05). According to RA evolution, RF, anti-CCP, and anti-MCV had higher levels in early RA. In addition, increased levels of IL-21 were observed in RA seropositive patients (RF/anti-CCP/anti-MCV). The higher levels of both cytokines and autoantibodies were observed in moderate activity, evaluated by the three indices.

CONCLUSIONS

Our results suggest that the increased soluble levels of IL-15, IL-21, and IFN-γ are involved in the inflammatory network in RA. However, IL-21 serum levels are associated with higher titers of autoantibodies (RF, anti-CCP, and anti-MCV) and IL-15 with moderate activity. Key Points • IL-15, IL-21, and IFN-y are associated with the immunopathology of RA, but not significantly with the evolution of the disease. • RF, anti-CCP, and anti-MCV had higher levels in early than established RA. • IL-21 has an association with RF, anti-CCP, and anti-MCVand, for this reason, could be proposed as a disease biomarker. • Patients with activity moderate of disease showed higher levels of RF, anti-CCP, anti-MCV, and IL-15.

How Autoantibodies Regulate Osteoclast Induced Bone Loss in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease, characterized by autoimmunity that triggers joint inflammation and tissue destruction. Traditional concepts of RA pathogenesis have strongly been focused on inflammation. However, more recent evidence suggests that autoimmunity per se modulates the disease and in particular bone destruction during the course of RA. RA-associated bone loss is caused by increased osteoclast differentiation and activity leading to rapid bone resorption. Autoimmunity in RA is based on autoantibodies such as rheumatoid factor (RF) and autoantibodies against citrullinated proteins (ACPA). These autoantibodies exert effector functions on immune cells and on bone resorbing osteoclasts, thereby facilitating bone loss. This review summarizes potential pathways involved in increased destruction of bone tissue in RA, particularly focusing on the direct and indirect actions of autoantibodies on osteoclast generation and function.

Post-Translational Modifications of Proteins: Novel Insights in the Autoimmune Response in Rheumatoid Arthritis

Post-translational modifications (PTM) are chemical changes mostly catalyzed by enzymes that recognize specific target sequences in specific proteins. These modifications play a key role in regulating the folding of proteins, their targeting to specific subcellular compartments, their interaction with ligands or other proteins, and eventually their immunogenic properties. Citrullination is the best characterized PTM in the field of rheumatology, with antibodies anticyclic citrullinated peptides being the gold standard for the diagnosis of rheumatoid arthritis (RA). In recent years, growing evidence supports not only that a wide range of proteins are subject to citrullination and can trigger an autoimmune response in RA, but also that several other PTMs such as carbamylation and acetylation occur in patients with this disease. This induces a wide spectrum of autoantibodies, as biomarkers, with different sensitivity and specificity for diagnosis, which may be linked to peculiar clinical manifestations and/or response to treatment. The purpose of this review article is to critically summarize the available literature on antibodies against post-translationally modified proteins, in particular antibodies against citrullinated proteins (ACPA) and antibodies against modified proteins (AMPA), and outline their diagnostic and prognostic role to be implemented in clinical practice for RA patients.

Assessing prognosis and prediction of treatment response in early rheumatoid arthritis: systematic reviews

BACKGROUND

Rheumatoid arthritis (RA) is a chronic, debilitating disease associated with reduced quality of life and substantial costs. It is unclear which tests and assessment tools allow the best assessment of prognosis in people with early RA and whether or not variables predict the response of patients to different drug treatments.

OBJECTIVE

To systematically review evidence on the use of selected tests and assessment tools in patients with early RA (1) in the evaluation of a prognosis (review 1) and (2) as predictive markers of treatment response (review 2).

DATA SOURCES

Electronic databases (e.g. MEDLINE, EMBASE, The Cochrane Library, Web of Science Conference Proceedings; searched to September 2016), registers, key websites, hand-searching of reference lists of included studies and key systematic reviews and contact with experts.

STUDY SELECTION

Review 1 - primary studies on the development, external validation and impact of clinical prediction models for selected outcomes in adult early RA patients. Review 2 - primary studies on the interaction between selected baseline covariates and treatment (conventional and biological disease-modifying antirheumatic drugs) on salient outcomes in adult early RA patients.

RESULTS

Review 1 - 22 model development studies and one combined model development/external validation study reporting 39 clinical prediction models were included. Five external validation studies evaluating eight clinical prediction models for radiographic joint damage were also included. c-statistics from internal validation ranged from 0.63 to 0.87 for radiographic progression (different definitions, six studies) and 0.78 to 0.82 for the Health Assessment Questionnaire (HAQ). Predictive performance in external validations varied considerably. Three models [(1) Active controlled Study of Patients receiving Infliximab for the treatment of Rheumatoid arthritis of Early onset (ASPIRE) C-reactive protein (ASPIRE CRP), (2) ASPIRE erythrocyte sedimentation rate (ASPIRE ESR) and (3) Behandelings Strategie (BeSt)] were externally validated using the same outcome definition in more than one population. Results of the random-effects meta-analysis suggested substantial uncertainty in the expected predictive performance of models in a new sample of patients. Review 2 - 12 studies were identified. Covariates examined included anti-citrullinated protein/peptide anti-body (ACPA) status, smoking status, erosions, rheumatoid factor status, C-reactive protein level, erythrocyte sedimentation rate, swollen joint count (SJC), body mass index and vascularity of synovium on power Doppler ultrasound (PDUS). Outcomes examined included erosions/radiographic progression, disease activity, physical function and Disease Activity Score-28 remission. There was statistical evidence to suggest that ACPA status, SJC and PDUS status at baseline may be treatment effect modifiers, but not necessarily that they are prognostic of response for all treatments. Most of the results were subject to considerable uncertainty and were not statistically significant.

LIMITATIONS

The meta-analysis in review 1 was limited by the availability of only a small number of external validation studies. Studies rarely investigated the interaction between predictors and treatment.

SUGGESTED RESEARCH PRIORITIES

Collaborative research (including the use of individual participant data) is needed to further develop and externally validate the clinical prediction models. The clinical prediction models should be validated with respect to individual treatments. Future assessments of treatment by covariate interactions should follow good statistical practice.

CONCLUSIONS

Review 1 - uncertainty remains over the optimal prediction model(s) for use in clinical practice. Review 2 - in general, there was insufficient evidence that the effect of treatment depended on baseline characteristics.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016042402.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Association of cumulative anti-cyclic citrullinated protein antibodies with radiographic progression in patients with rheumatoid arthritis

INTRODUCTION

Antibody against cyclic citrullinated protein (ACPA) is counted as one of the most important biomarkers in diagnosis, classification, and prognosis of rheumatoid arthritis (RA). We examined the evolution of ACPA during disease course and assess predictive value of time-weighted cumulative ACPA titer on radiographic progression in RA patients.

METHOD

A group of 734 patients with RA was followed longitudinally over 2 years, with annual measurements of ACPA. The cumulative titers of ACPA were calculated using the trapezoidal rule and were divided into three categories: negative, low-to-moderate, and high. Radiographs of the hands were scored with the modified Sharp score (SHS). Multivariable logistic regression models were performed to identify independent predictors over follow-up for individual patients with different combinations of risk factors. The effect size was computed by Cohen's d method.

RESULTS

The patients with radiographic progression had a higher SHS at baseline; and smoking status, diabetes, RF positivity, and use of biologic DMARDs were independently associated with radiographic progression (all P < 0.05). As for ACPA, reversion happened more commonly in men and was associated with younger onset age and lower titer at baseline, but it had no direct relevance to radiographic outcome. In multivariable regression analysis, only high cumulative or baseline titer of ACPA had a predictive power for rapid radiographic progression (all P < 0.05), and cumulative ACPA titer was superior in terms of statistical significance (Cohen's d, 0.637 versus 0.583).

CONCLUSIONS

High cumulative ACPA titer was independently associated with accelerated radiographic progression, especially with initiation of joint damage.

Early Peritoneal CC Chemokine Production Correlates with Divergent Inflammatory Phenotypes and Susceptibility to Experimental Arthritis in Mice

The inflammatory and autoimmune events preceding clinical symptoms in rheumatoid arthritis (RA) and other autoimmune diseases are difficult to study in human patients. Therefore, animal models that share immunologic and clinical features with human RA, such as pristane-induced arthritis (PIA), are valuable tools for assessing the primordial events related to arthritis susceptibility. PIA-resistant HIII and susceptible LIII mice were injected i.p. with pristane, and peritoneal lavage fluid was harvested in the early (7 days) and late (35 days) preclinical phases of PIA. Chemokine and cytokine levels were measured in lavage supernatant with ELISA, peritoneal inflammatory leukocytes were immunophenotyped by flow cytometry, and gene expression was determined by qRT-PCR. Leukocyte recruitment was quantitatively and qualitatively divergent in the peritoneum of HIII and LIII mice, with an early increase of CC chemokines (CCL2/CCL3/CCL5/CCL12/CCL22) in the susceptible LIII strain. Also, cytokines such as IL-12p40, IL-23, and IL-18 were elevated in LIII mice while IL-6 was increased in HIII animals. The results show that an early peritoneal CC chemokine response is an important feature of arthritis susceptibility and defines potential biomarkers in this model.

Osteoimmunology of Bone Loss in Inflammatory Rheumatic Diseases

Over the past two decades, the field of osteoimmunology has emerged in response to a range of evidence demonstrating the reciprocal relationship between the immune system and bone. In particular, localized bone loss, in the form of joint erosions and periarticular osteopenia, as well as systemic osteoporosis, caused by inflammatory rheumatic diseases including rheumatoid arthritis, the prototype of inflammatory arthritis has highlighted the importance of this interplay. Osteoclast-mediated resorption at the interface between synovium and bone is responsible for the joint erosion seen in patients suffering from inflammatory arthritis. Clinical studies have helped to validate the impact of several pathways on osteoclast formation and activity. Essentially, the expression of pro-inflammatory cytokines as well as Receptor Activator of Nuclear factor κB Ligand (RANKL) is, both directly and indirectly, increased by T cells, stimulating osteoclastogenesis and resorption through a crucial regulator of immunity, the Nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1). Furthermore, in rheumatoid arthritis, autoantibodies, which are accurate predictors both of the disease and associated structural damage, have been shown to stimulate the differentiation of osteoclasts, resulting in localized bone resorption. It is now also evident that osteoblast-mediated bone formation is impaired by inflammation both in joints and the skeleton in rheumatoid arthritis. This review summarizes the substantial progress that has been made in understanding the pathophysiology of bone loss in inflammatory rheumatic disease and highlights therapeutic targets potentially important for the cure or at least an alleviation of this destructive process.

Sequential Prodrug Strategy To Target and Eliminate ACPA-Selective Autoreactive B Cells

Autoreactive B cells are thought to play a pivotal role in many autoimmune diseases. Rheumatoid arthritis (RA) is an autoimmune disease affecting ∼1% of the Western population and is hallmarked by the presence of anticitrullinated proteins antibodies (ACPA) produced by autoreactive B cells. We intend to develop a method to target and selectively eliminate these autoreactive B cells using a sequential antigen prodrug targeting strategy. As ACPA-expressing B cells are thought to play essential roles in RA-disease pathogenesis, we used this B cell response as a prototype to analyze the feasibility to generate a construct consisting of a biologically silenced, that is, blocked, antigen connected to a cytotoxic prodrug. Blocking of the antigen is considered relevant as it is anticipated that circulating autoantibodies will otherwise clear the antigen-prodrug before it can reach the target cell. The antigen-prodrug can only bind to the autoantigen-specific B cell receptor (BCR) upon enzymatic removal of the blocking group in close proximity of the B cell surface. BCR binding ultimately induces antigen-specific cytotoxicity after internalization of the antigen. We have synthesized a cyclic citrullinated peptide (CCP) antigen suitable for BCR binding and demonstrated that binding by ACPA was impaired upon introduction of a carboxy-p-nitrobenzyl (CNBz) blocking group at the side chain of the citrulline residue. Enzymatic removal of the CNBz moiety by nitroreductase fully restored citrulline-specific recognition by both ACPA and ACPA-expressing B cells and showed targeted cell death of CCP-recognizing B cells only. These results mark an important step toward antigen-specific B cell targeting in general and more specifically in RA, as successful blocking and activation of citrullinated antigens forms the basis for subsequent use of such construct as a prodrug in the context of autoimmune diseases.

Bone erosions in rheumatoid arthritis: recent developments in pathogenesis and therapeutic implications

Bone erosions develop early in the course of rheumatoid arthritis (RA) and deteriorate progressively, causing joint damage and resulting in impaired functional capacity of patients. During the last years, considerable number of studies has increased our understanding of the pathogenetic mechanisms mediating the development of bone erosions in RA. Increased production of RANKL and other cytokines, dysregulation of innate immune mechanisms, autoantibodies specific to RA and alterations of microRNA expression stimulate differentiation and function of osteoclasts, which are responsible for the development of bone erosions. Besides, increased levels of cytokines, overproduction of antagonists of the canonical Wnt signaling pathway and deficient production of bone morphogenetic proteins result in impaired osteoblast differentiation and function, undermining the capacity of bone erosions to repair. Disease-modifying antirheumatic drugs, synthetic or biological, currently used in the treatment of RA, can halt the progression of bone erosions and may even lead to partial repair, although complete repair is unattainable. Targeting pathogenetic mechanisms participating in the erosive process may add to the therapeutic effect of DMARDs and help in the prevention or repair of bone erosions. However, more studies are still needed to confirm whether such therapeutic strategies are effective.

Curcumin for the Management of Periodontitis and Early ACPA-Positive Rheumatoid Arthritis: Killing Two Birds with One Stone

We propose curcumin as a preventive measure to avoid/manage periodontitis (PD), and as a natural immunosuppressant for rheumatoid arthritis (RA). PD, mainly caused by Porphyromonas gingivalis forming biofilm and leading to tooth decay, is a major public health issue and a risk factor for the development of RA in humans. P. gingivalis is able to trigger experimental autoimmune arthritis in animal models and in humans can induce citrullinated peptides, which not only are a source of anti-citrullinated antibodies (ACPAs), but also participate in autoreactive responses and disease development. Curcumin appears to have efficient anti-bacterial activity against P. gingivalis infection and biofilm formation. In addition to antibacterial, anti-oxidant, and anti-inflammatory action, curcumin exerts unique immunosuppressant properties via the inhibition of Th17 pro-inflammatory responses and promotion of regulatory T cells, thus suppressing autoimmunity. We introduce curcumin as a natural product for the management of both PD and RA-related autoreactivity, possibly also as a preventive measure in early RA or individuals at high risk to develop RA.

The Role of Autoantibodies in Bone Metabolism and Bone Loss

Many autoimmune diseases are associated with deranged bone metabolism. The resulting localized or systemic bone loss can compromise the quality of life of patients by causing local bone deformities or fragility fractures. There is emerging evidence that antibodies have a direct impact on key players of bone homeostasis, in particular osteoclasts. Clinical and pre-clinical studies provide insight into the function of autoantibodies related to Rheumatoid Arthritis (rheumatoid factor, anti-citrullinated protein antibodies, and anti-carbamylated protein antibodies) and their inflammation-independent interaction with bone cells. Furthermore, we summarize the current knowledge about neutralizing antibodies to the antiresorptive protein osteoprotegerin, which have been described in patients with Coeliac Disease, Rheumatoid Arthritis, and Spondyloarthritis.

Interleukin-6 and IgA-rheumatoid factor are crucial for baseline erosiveness, and anti-citrullinated peptide antibodies for radiographic progression in early rheumatoid arthritis treated according to a treat-to-target strategy

OBJECTIVES

To define baseline clinical and immunological characteristics [anti-citrullinated peptide antibodies (ACPAs), immunoglobulin M (IgM)- and IgA-rheumatoid factor (RF), and interleukin-6 (IL-6) levels] involved in determining baseline erosiveness, outcome, and radiographic progression among seropositive and seronegative early rheumatoid arthritis (ERA) patients.

METHOD

The 408 ERA patients enrolled in the study were monitored every 3 months according to the treat-to-target strategy. At baseline and after 12 months, hand and foot radiographs were evaluated using the Sharp/van der Heijde erosion score.

RESULTS

At diagnosis, seronegative patients were older and had higher Disease Activity Scores (DASs) than seropositive patients. A higher risk of erosiveness at baseline was conferred by IgA-RF positivity and IL-6 plasma levels ≥7.6 pg/mL, particularly when simultaneously present. In multivariate analysis, disease duration and IL-6 plasma levels ≥7.6 pg/mL arose as independent variables associated with presence of erosions at onset. Radiographic progression at 1 year follow-up, which occurred in 11.1% of ERA patients, was predicted by ACPA positivity, together with higher age at diagnosis. Despite similar percentages of good European League Against Rheumatism response, DAS and Boolean remission being observed over time among seropositive and seronegative patients and between erosive and non-erosive subjects, ERA patients who were erosive at onset, IgA-RF seropositive, and simultaneously having high baseline IL-6 plasma levels (≥7.6 pg/mL) were treated to a greater extent with tumour necrosis factor blockers after 12 months.

CONCLUSION

IgA-RF positivity and IL-6 plasma levels are crucial for baseline erosiveness, while ACPA positivity represents the strongest risk factor for developing radiographic progression in ERA.

Effects of denosumab on bone metabolism and bone mineral density with anti-TNF inhibitors, tocilizumab, or abatacept in osteoporosis with rheumatoid arthritis

Introduction

The aim of this 18-month retrospective study was to evaluate the differences in outcomes of denosumab with tumor necrosis factor (TNF) inhibitors (TNFis), tocilizumab (TCZ), or abatacept (ABT) treatment in osteoporosis (OP) patients with rheumatoid arthritis (RA).

Patients and methods

Patients were divided into TNFis-treated (TNF group; 44 cases), TCZ-treated (TCZ group; 8 cases), or ABT-treated (ABT group; 14 cases) groups. We measured serum bone-specific alkaline phosphatase (BAP) and tartrate-resistant acid phosphatase 5b (TRACP-5b) at baseline and every 3 months for 18 months and assessed bone mineral density (BMD) of the lumbar 1–4 vertebrae (L-BMD) and total hip BMD (H-BMD) at baseline and every 6 months for 18 months.

Results

There were no significant differences in the percent changes in BAP, TRACP-5b, or L-BMD among the groups. The percent change in H-BMD was significantly increased in the TCZ group at 12 months or at 12 and 18 months, compared with that in the ABT group or TNF group, respectively. The percent change in L-BMD was significantly increased at 12 months in the TCZ and TNF groups, and at 18 months in all the 3 groups compared with pretreatment levels, whereas the percent change in H-BMD was significantly higher at 6, 12, and 18 months in the TCZ group, at 12 and 18 months in the TNF group, and at 18 months in the ABT group, compared with pretreatment levels.

Conclusion

Our findings suggest that TCZ might be more useful than TNF or ABT in light of the observed H-BMD increases with denosumab therapy for OP patients with RA.

Comparative evaluation of treatment patterns and healthcare utilization of newly-diagnosed rheumatoid arthritis patients by anti-cyclic citrullinated peptide antibody status

BACKGROUND

Anti-cyclic citrullinated peptide (CCP) antibody positivity is an established diagnostic factor for severe disease activity and joint damage and a prognostic factor for aggressive disease in rheumatoid arthritis (RA).

OBJECTIVE

To compare RA-related treatment, healthcare utilization, and joint erosion between anti-CCP-positive and anti-CCP-negative RA patients.

METHODS

Newly-diagnosed RA patients were identified from the Henry Ford Health System database between January 1, 2009 and December 31, 2014; the date of the first RA diagnosis within the study period was the index date. Baseline anti-CCP test was used to categorize patients as anti-CCP-positive or anti-CCP-negative, and outcomes were evaluated in the 6 months post-index.

RESULTS

There were 217 anti-CCP-positive and 191 anti-CCP-negative RA patients included in the study. A higher proportion of anti-CCP-positive patients were initiated on RA treatment than anti-CCP-negative patients (70.5% vs 23.0%; p < .0001). More anti-CCP-positive patients received methotrexate (73.2% vs 56.8%; p = .0374), while more anti-CCP-negative patients received hydroxychloroquine (31.8% vs 13.1%; p = .0037) in first-line therapy. A higher proportion of anti-CCP-negative patients were tested for rheumatoid factor (RF) and erythrocyte sedimentation rate (ESR). Of those tested, there were more positive test results in the anti-CCP-positive cohort compared to the anti-CCP-negative cohort (RF: 84.4% vs 18.2%, p < .0001; C-reactive protein [CRP]: 69.7% vs 48.3%, p = .0008; and ESR: 89.5% vs 53.9%, p < .0001). Outpatient utilization predominated, with more anti-CCP-positive patients having any outpatient physician office visit (96.3% vs 77.5%, p < .0001) and a higher mean number of visits (5.3 vs 2.5, p < .0001) than anti-CCP-negative patients. Among anti-CCP-positive (n = 113) and anti-CCP-negative (n = 58) patients with imaging results, more anti-CCP-positive patients had joint erosion compared to anti-CCP-negative patients (18.6% vs 8.6%; p = .0858); however, statistical significance was not reached.

CONCLUSION

RA patients with positive anti-CCP antibodies had higher degrees of inflammation and disease activity as indicated by laboratory results, which likely contributed to their higher rates of healthcare utilization, joint erosion, and proportions of RA treatment.

Anti-mutated citrullinated vimentin antibodies in antiphospholipid syndrome: diagnostic value and relationship with clinical features

Antiphospholipid antibodies (aPLs) are a heterogeneous group of autoantibodies essential for the diagnosis of antiphospholipid syndrome (APS) but do not predict clinical manifestations or disease progression. Hence, the co-presence of other antibodies may prove useful. Autoimmunity directed toward vimentin and other citrullinated peptides was established in rheumatoid arthritis (RA) and in other autoimmune conditions including systemic lupus erythematosus (SLE). We have previously described the presence of autoantibodies directed against vimentin/cardiolipin complex in patients with antiphospholipid syndrome (APS), but there are no data on the role of citrullinated vimentin in APS. Thus, we evaluated the prevalence and clinical significance of anti-MCV in APS patients. The study group consisted of 79 unselected outpatients with APS. Control groups included 25 patients with SLE, 30 patients with RA, and 20 healthy subjects age- and sex-matched. To detect anti-MCV, anti-vimentin, anti-vimentin/cardiolipin, and anti-CCP2 antibodies, commercial or homemade enzyme-linked immunosorbent assays (ELISA) were performed. Anti-MCV antibodies were found in a high percentage of APS patients (26.6%). A significant correlation between anti-MCV and anti-vimentin/cardiolipin serum levels was observed (p = 0.029). Moreover, vimentin reactivity was increased by its citrullination or conjugation with cardiolipin (p = 0.01 and p < 0.001, respectively). Interestingly, anti-MCV was found associated with the presence of arthritis (p = 0.011) and anti-vimentin/cardiolipin was highly specific for the presence of arterial or venous thrombosis in APS (p = 0.003 and p = 0.002, respectively). The detection of additional autoantibodies may contribute to clinical assessment of APS patients. Citrullination may occur in APS and play a role in the pathogenesis of this condition.

KEY POINTS

•Anti-MCV antibodies can be found in APS patients and are associated with the presence of arthritis. •Anti-vimentin/cardiolipin is strongly associated with the presence of thrombosis (both arterial and venous). •Citrullination occurs in APS, participate in disease pathogenesis, and influence clinical picture.