Decrease of anti-cyclic citrullinated peptide antibodies and rheumatoid factor following anti-TNFalpha therapy (infliximab) in rheumatoid arthritis is associated with clinical improvement

Rheumatoid factors revisited in the age of biologic therapy

The discovery of RF has been instrumental in diagnosing and classifying RA. Various RF isotypes, including IgM-RF and IgA-RF, have been linked to disease severity and treatment responses. The role of RF in RA pathogenesis, primarily through the formation of immune complexes, also carries the potential to influence the response to different medications. Recent progress in biologic therapies has further elucidated the role of RF in RA management. Treatments such as rituximab, abatacept and tocilizumab have shown differential efficacy based on RF status, with RF-positive patients often exhibiting better responses. Recent research also suggests that TNF inhibitors (TNFi) lacking the IgG1-Fc fragment like certolizumab pegol (CZP) may offer advantages over TNFi with an IgG1-Fc fragment, in RF-positive patients by preventing immune complex formation. Since this early observation is predominantly derived from previous multicentre studies with heterogeneous populations and potentially varying RF measurement methods, prospective randomized studies directly addressing this issue are essential for a more thorough and reliable evaluation. This paper is a narrative review outlining the evolving understanding of RF in the context of biologic therapies, emphasizing the need for personalized treatment approaches based on serological profiles and underlying immune mechanisms.

The prevalence and risk factors of rheumatoid arthritis-associated interstitial lung disease: a systematic review and meta-analysis

BACKGROUND

Interstitial lung disease (ILD) is the most widespread and fatal pulmonary complication of rheumatoid arthritis (RA). Existing knowledge on the prevalence and risk factors of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is inconclusive. Therefore, we designed this review to address this gap.

MATERIALS AND METHODS

To find relevant observational studies discussing the prevalence and/or risk factors of RA-ILD, EMBASE, Web of Science, PubMed, and the Cochrane Library were explored. The pooled odds ratios (ORs) / hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated with a fixed/ random effects model. While subgroup analysis, meta-regression analysis and sensitivity analysis were carried out to determine the sources of heterogeneity, the I2 statistic was utilized to assess between-studies heterogeneity. Funnel plots and Egger's test were employed to assess publication bias. Following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, our review was conducted.

RESULTS

A total of 56 studies with 11,851 RA-ILD patients were included in this meta-analysis. The pooled prevalence of RA-ILD was 18.7% (95% CI 15.8-21.6) with significant heterogeneity (I2 = 96.4%). The prevalence of RA-ILD was found to be more likely as a result of several identified factors, including male sex (ORs = 1.92 95% CI 1.70-2.16), older age (WMDs = 6.89, 95% CI 3.10-10.67), having a smoking history (ORs =1.91, 95% CI 1.48-2.47), pulmonary comorbidities predicted (HRs = 2.08, 95% CI 1.89-2.30), longer RA duration (ORs = 1.03, 95% CI 1.01-1.05), older age of RA onset (WMDs =4.46, 95% CI 0.63-8.29), positive RF (HRs = 1.15, 95%CI 0.75-1.77; ORs = 2.11, 95%CI 1.65-2.68), positive ACPA (ORs = 2.11, 95%CI 1.65-2.68), higher ESR (ORs = 1.008, 95%CI 1.002-1.014), moderate and high DAS28 (≥3.2) (ORs = 1.87, 95%CI 1.36-2.58), rheumatoid nodules (ORs = 1.87, 95% CI 1.18-2.98), LEF use (ORs = 1.42, 95%CI 1.08-1.87) and steroid use (HRs= 1.70, 1.13-2.55). The use of biological agents was a protective factor (HRs = 0.77, 95% CI 0.69-0.87).

CONCLUSION(S)

The pooled prevalence of RA-ILD in our study was approximately 18.7%. Furthermore, we identified 13 risk factors for RA-ILD, including male sex, older age, having a smoking history, pulmonary comorbidities, older age of RA onset, longer RA duration, positive RF, positive ACPA, higher ESR, moderate and high DAS28 (≥3.2), rheumatoid nodules, LEF use and steroid use. Additionally, biological agents use was a protective factor.

Anti-citrullinated protein antibodies as biomarkers in rheumatoid arthritis

INTRODUCTION

The serological biomarker anti-citrullinated protein antibodies (ACPAs) may have several functions but is especially important for the diagnosis of rheumatoid arthritis (RA) along with clinical symptoms.

AREAS COVERED

This review provides an overview of ACPAs, which are useful in RA diagnostics and may improve our understanding of disease etiology. PubMed was searched with combinations of words related to antibodies recognizing epitopes containing the post-translationally modified amino acid citrulline in combination with rheumatoid arthritis; cyclic citrullinated peptide, CCP, anti-CCP, anti-citrullinated protein antibodies, ACPA, citrullination, peptide/protein arginine deiminase, PAD, filaggrin, vimentin, keratin, collagen, perinuclear factor, EBNA1, EBNA2, and others. From this search, we made a qualitative extract of publications relevant to the discovery, characterization, and clinical use of these antibodies in relation to RA. We highlight significant findings and identify areas for improvement.

EXPERT OPINION

ACPAs have high diagnostic sensitivity and specificity for RA and recognize citrullinated epitopes from several proteins. The best-performing single epitope originates from Epstein-Barr Virus nuclear antigen 2 and contains a central Cit-Gly motif, which is recognized by ACPAS when located in a flexible peptide structure. In addition, ACPAs may also have prognostic value, especially in relation to early treatment, although ACPAs' main function is to aid in the diagnosis of RA.

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.

Association Between Baseline Anti-cyclic Citrullinated Peptide Antibodies and 6-Month Clinical Response Following Abatacept or TNF Inhibitor Treatment: A Real-World Analysis of Biologic-Experienced Patients with RA

INTRODUCTION

Anti-cyclic citrullinated peptide (anti-CCP) antibodies are associated with poor prognosis in patients with rheumatoid arthritis (RA). Previous data from randomized controlled trials and clinical practice have shown anti-CCP-positive (+) patients had a better response to treatment with abatacept or tumor necrosis factor inhibitor (TNFi) treatment than those who were anti-CCP negative. This study assessed the association between baseline anti-CCP2 [a surrogate for anti-citrullinated protein antibody (ACPA)] concentration and 6-month treatment responses to abatacept or TNFi in patients with RA.

METHODS

This real-world analysis included biologic-experienced patients from CERTAIN (Comparative Effectiveness Registry to study Therapies for Arthritis and Inflammatory CoNditions) who initiated abatacept or TNFi, had prior biologic disease-modifying drug exposure and baseline anti-CCP2 concentration/serostatus and serum samples (baseline and 6 months). Baseline demographics and disease characteristics were compared. Change from baseline at 6 months in Clinical Disease Activity Index (CDAI) score and patient-reported outcomes [PROs: pain, fatigue, patient global assessment (PtGA), modified Health Assessment Questionnaire (mHAQ) score], by baseline anti-CCP2 quartile and binary cut-off (> 10-250 and > 250 U/ml), were evaluated separately in the abatacept and TNFi groups using a linear regression model adjusted for age, sex, CDAI/PROs, comorbidity index, and methotrexate use.

RESULTS

Included were 138 abatacept and 137 TNFi initiators who were anti-CCP2+. At baseline, there were significant differences between anti-CCP2 quartiles and mean CDAI, swollen joint count 28, C-reactive protein (CRP), Disease Activity Score 28 (CRP), rheumatoid factor (RF), mHAQ and physician global assessment among abatacept initiators, and in mean RF, mHAQ, and PtGA among TNFi initiators. Among abatacept (but not TNFi) initiators, CDAI numerically improved (p = 0.208) and PROs significantly improved (p < 0.05) with increasing baseline anti-CCP2.

CONCLUSIONS

In patients treated with abatacept, not TNFi, higher anti-CCP2 concentrations at baseline were associated with numerically greater improvements in CDAI and significant improvements in PROs after 6 months.

CLINICAL TRIAL NUMBER

NCT01625650.

Atypical phenotype and response of B cells in patients with seropositive rheumatoid arthritis

Patients with rheumatoid arthritis (RA) may be classified as seropositive or seronegative according to the presence of autoantibodies. An abnormal B cell phenotype and function could be one of the main components of the immunopathology of seropositive patients; however, there is little information regarding B cell defects in these patients. This study shows a broad characterization of the B cell phenotype and function in patients with seropositive RA. We focused mainly on the evaluation of subsets, the expression of modulatory molecules of cell activation (CD22, FcɣRIIb and FcµR), calcium mobilization, global tyrosine phosphorylation, expression of activation markers, cytokine and immunoglobulin (Ig) production, proliferation and the in-vitro generation of plasma cells. Increased frequency of CD27^- IgM^- IgD^- and CD21^- B cells was observed in patients with seropositive RA compared with healthy donors (HD). Decreased expression of CD22 was primarily found in memory B cells of patients with RA regardless of seropositivity. B cells from seropositive patients exhibited normal proliferation, calcium mobilization kinetics and global tyrosine phosphorylation, but showed an increased frequency of CD86⁺ B cells compared with HD. B cells of seropositive patients secrete less interleukin-10 after in-vitro activation and showed a decreased frequency of plasma cell differentiation and IgM production compared with HD. Our data indicate that patients with seropositive RA have an increased frequency of atypical B cell populations previously associated with chronic activation and antigen exposure. This may result in the observed low responsiveness of these cells in vitro.

Anti-cyclic citrullinated peptide antibody in the cerebrospinal fluid in patients with rheumatoid arthritis who have central nervous system involvement

Central nervous system (CNS) involvement, including encephalopathy, encephalitis, leptomeningitis, and pachymeningitis, in rheumatoid arthritis (RA) is rather rare. We report the case of a 61-year-old female with a history of RA in remission for 7 years, who presented with numbness, weakness of the left upper limb, dysarthria, and headache. Magnetic resonance imaging (MRI) of the brain showed meningeal enhancement in the frontal, parietal, and temporal lobes. Cerebrospinal fluid (CSF) examination detected high levels of both rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA), with a high ACPA-immunoglobulin G index (> 2.0). She was diagnosed with rheumatoid meningitis. Following combined therapy with oral prednisolone and intravenous infusion of cyclophosphamide, her symptoms promptly improved. After treatment, RF and ACPA levels in the CSF were reduced, and MRI showed improvement of the meningeal structures. This case, along with existing literature, suggests that the ACPA level in the CSF may serve as a useful marker for diagnosing of CNS involvement in RA, as well as an index of effectiveness of the associated treatment.

Anti-HLA Class II Antibodies Correlate with C-Reactive Protein Levels in Patients with Rheumatoid Arthritis Associated with Interstitial Lung Disease

The pathogenesis of Rheumatoid Arthritis (RA) is not fully understood, probably influenced by genetic and environmental factors. Interstitial Lung Disease (ILD) is an extra-articular manifestation of RA, which contributes significantly to morbidity and mortality. The identification of anti-HLA antibodies has been useful in the transplantation field; however, its contribution to autoimmune diseases as RA has not been fully studied. We aimed to determine the presence of anti-HLA antibodies in RA patients with and without ILD and its possible association with clinical and biochemical markers. One-hundred and forty-seven RA patients, of which 65 had ILD (RA-ILD group), were included. Sera samples for Anti-HLA Class II LABScreen panel-reactive antibodies (PRA) were analyzed. In both groups, women predominated, and lung function was worse in patients with ILD. The anti-CCP+ (UI/mL) was higher in the RA group in comparison to RA-ILD (p < 0.001). Expositional risk factors (tobacco smoking and biomass-burning smoke) were higher in RA-ILD patients. PRA+ was identified in ~25% RA-ILD patients, while ~29% in the RA group. The CRP levels have a positive correlation with the percentage of reactivity (%PRA, p = 0.02, r2 = 0.60) in the RA-ILD group. In conclusion, anti-HLA antibodies correlate with C-reactive protein levels in RA patients with ILD.

A predominant involvement of the triple seropositive patients and others with rheumatoid factor in the association of smoking with rheumatoid arthritis

The major environmental risk factor for rheumatoid arthritis (RA) is smoking, which according to a widely accepted model induces protein citrullination in the lungs, triggering the production of anti-citrullinated protein antibodies (ACPA) and RA development. Nevertheless, some research findings do not fit this model. Therefore, we obtained six independent cohorts with 2253 RA patients for a detailed analysis of the association between smoking and RA autoantibodies. Our results showed a predominant association of smoking with the concurrent presence of the three antibodies: rheumatoid factor (RF), ACPA and anti-carbamylated protein antibodies (ACarPA) (3 Ab vs. 0 Ab: OR = 1.99, p = 2.5 × 10^–8). Meta-analysis with previous data (4491 patients) confirmed the predominant association with the concurrent presence of the three antibodies (3 Ab vs. 0 Ab: OR = 2.00, p = 4.4 ×10^–16) and revealed that smoking was exclusively associated with the presence of RF in patients with one or two antibodies (RF⁺₁₊₂vs. RF⁻₀₊₁₊₂: OR = 1.32, p = 0.0002). In contrast, no specific association with ACPA or ACarPA was found. Therefore, these results showed the need to understand how smoking favors the concordance of RA specific antibodies and RF triggering, perhaps involving smoking-induced epitope spreading and other hypothesized mechanisms.

Association of Seropositivity and Mortality in Rheumatoid Arthritis and the Impact of Treatment With Disease-Modifying Antirheumatic Drugs: Results From a Real-World Study

OBJECTIVE

Seropositivity for anti-citrullinated protein antibody (ACPA)/rheumatoid factor (RF) in rheumatoid arthritis (RA) is associated with increased overall mortality; however, the association between antibody titers and mortality is not well established. Investigating relationships between antibody titers and mortality may clarify their role in RA pathogenesis. This study was undertaken to evaluate the association of antibody titers with mortality and its modification by disease-modifying antirheumatic drugs (DMARDs).

METHODS

Eligible patients with established RA were identified through administrative claims data linked to laboratory results (2005-2016). Patients were categorized by positivity status for ACPA, RF, or both. Patients were further divided into groups by autoantibody titers. DMARD-exposed patients were categorized into biologic DMARD (bDMARD) and conventional DMARD (cDMARD) subcohorts. Crude mortality rates/1,000 patient-years and Kaplan-Meier curves were compared between antibody categories. Adjusted Cox proportional hazards regression and sensitivity (propensity-matched patients) analyses were conducted.

RESULTS

Overall, 53,849 and 79,926 patients had evaluable ACPA and RF status, respectively. For both autoantibodies, mortality rates were significantly higher in seropositive versus seronegative patients (risk increase of 48.0% and 44.0% in ACPA- and RF-positive patients, respectively; P < 0.001 each). Mortality rates were greatest in patients with higher versus lower autoantibody titers (ACPA hazard ratio [HR] 1.60 [95% confidence interval (95% CI]) 1.45-1.76]; RF HR 1.78 [95% CI 1.66-1.91]). In cDMARD-exposed patients, HRs were higher in seropositive versus seronegative cohorts; in bDMARD-exposed patients, there was no difference in mortality by serostatus.

CONCLUSION

Elevated ACPA/RF titers were independently associated with increased mortality among patients with RA and persisted in patients treated with cDMARDs but not with bDMARDs.

Does immunological remission, defined as disappearance of autoantibodies, occur with current treatment strategies? A long-term follow-up study in rheumatoid arthritis patients who achieved sustained DMARD-free status

OBJECTIVES

Sustained disease-modifying antirheumatic drug (DMARD)-free status, the sustained absence of synovitis after cessation of DMARD therapy, is infrequent in autoantibody-positive rheumatoid arthritis (RA), but approximates cure (ie, disappearance of signs and symptoms). It was recently suggested that immunological remission, defined as disappearance of anti-citrullinated protein antibodies (ACPA) and rheumatoid factor (RF), underlies this outcome. Therefore, this long-term observational study determined if autoantibodies disappear in RA patients who achieved sustained DMARD-free remission.

METHODS

We studied 95 ACPA-positive and/or RF-positive RA patients who achieved DMARD-free remission after median 4.8 years and kept this status for the remaining follow-up (median 4.2 years). Additionally, 21 autoantibody-positive RA patients with a late flare, defined as recurrence of clinical synovitis after a DMARD-free status of ≥1 year, and 45 autoantibody-positive RA patients who were unable to stop DMARD therapy (during median 10 years) were studied. Anti-cyclic citrullinated peptide 2 (anti-CCP2) IgG, IgM and RF IgM levels were measured in 587 samples obtained at diagnosis, before and after achieving DMARD-free remission.

RESULTS

13% of anti-CCP2 IgG-positive RA patients had seroreverted when achieving remission. In RA patients with a flare and persistent disease this was 8% and 6%, respectively (p=0.63). For anti-CCP2 IgM and RF IgM, similar results were observed. Evaluating the estimated slope of serially measured levels revealed that RF levels decreased more in patients with than without remission (p<0.001); the course of anti-CCP2 levels was not different (p=0.66).

CONCLUSIONS

Sustained DMARD-free status in autoantibody-positive RA was not paralleled by an increased frequency of reversion to autoantibody negativity. This form of immunological remission may therefore not be a treatment target in patients with classified RA.

Autoantibodies as Diagnostic Markers and Mediator of Joint Inflammation in Arthritis

Rheumatoid arthritis is a systemic, polygenic, and multifactorial syndrome characterized by erosive polyarthritis, damage to joint architecture, and presence of autoantibodies against several self-structures in the serum and synovial fluid. These autoantibodies (anticitrullinated protein/peptide antibodies (ACPAs), rheumatoid factors (RF), anticollagen type II antibodies, antiglucose-6 phosphate isomerase antibodies, anticarbamylated protein antibodies, and antiacetylated protein antibodies) have different characteristics, diagnostic/prognostic value, and pathological significance in RA patients. Some of these antibodies are present in the patients' serum several years before the onset of clinical disease. Various genetic and environmental factors are associated with autoantibody production against different autoantigenic targets. Both the activating and inhibitory FcγRs and the activation of different complement cascades contribute to the downstream effector functions in the antibody-mediated disease pathology. Interplay between several molecules (cytokines, chemokines, proteases, and inflammatory mediators) culminates in causing damage to the articular cartilage and bones. In addition, autoantibodies are proven to be useful disease markers for RA, and different diagnostic tools are being developed for early diagnosis of the clinical disease. Recently, a direct link was proposed between the presence of autoantibodies and bone erosion as well as in the induction of pain. In this review, the diagnostic value of autoantibodies, their synthesis and function as a mediator of joint inflammation, and the significance of IgG-Fc glycosylation are discussed.

Soluble Lectin-like Oxidized Low-Density Lipoprotein Receptor 1 Predicts the Changes of Rheumatoid Factor Titers in Rheumatoid Arthritis

OBJECTIVE

The aim of this longitudinal study was to examine the clinical significance of soluble lectin-like oxidized low-density lipoprotein receptor 1 (sLOX-1) in patients with rheumatoid arthritis.

METHODS

We gathered demographic and clinical data for a large rheumatoid arthritis cohort at 3 time points. Blood samples were collected at each time point; the number of samples was 282 cases in 2012, 431 cases in 2013, and 500 cases in 2014. Plasma sLOX-1 was measured by enzyme-linked immunosorbent assay. Correlations between sLOX-1 and clinical data were analyzed. Predictive factors associated with changes in sLOX-1 and rheumatoid factor (RF) were analyzed by multivariate linear regression.

RESULTS

Plasma sLOX-1 level was significantly correlated with RF titer and other clinical parameters. The longitudinal analyses showed that changes in sLOX-1 were significantly correlated with changes in RF titers and with those at baseline. Multivariate linear regression analysis revealed that changes in RF and baseline RF were predictive factors for changes in sLOX-1. Conversely, the changes in RF were significantly correlated with the changes in sLOX-1 in all years. A stepwise regression analysis showed that the change in sLOX-1 was a predictive factor for the change in RF.

CONCLUSIONS

The change in sLOX-1 has predictive value for assessing the change in RF, indicating the usefulness of sLOX-1 in clinical practice.

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.

Laboratory Assessment of Patients with Suspected Rheumatic Musculoskeletal Diseases: Challenges and Pitfalls

Current patient care in rheumatology relies primarily on a combination of traditional clinical assessment and standard laboratory tests. Investigators seek to discover new biomarkers and novel technologies to boost the research in this field. Mechanistic biomarkers such as cytokines, cell types, antibodies, signaling molecules, are rooted in the mechanism underlying the disease and can guide the clinical management of the disease. Conversely, descriptive biomarkers are byproducts of the disease process, depict the state of a disease but are not involved in its pathogenesis. In this article, we reviewed the field of common laboratory biomarkers in rheumatology, highlighting both their descriptive or mechanistic value as well as their role in clinical practice.

Comparative Effectiveness of Abatacept Versus Tumor Necrosis Factor Inhibitors in Patients with Rheumatoid Arthritis Who Are Anti-CCP Positive in the United States Corrona Registry

Introduction

Anti-citrullinated protein antibodies (ACPAs) are highly specific serological biomarkers that are indicative of a poor prognosis in patients with rheumatoid arthritis (RA). The effectiveness of biologic disease-modifying antirheumatic drugs (bDMARDs) with different mechanisms of action may vary, based on patients’ serostatus. The aim of this study is to compare the effectiveness of abatacept versus tumor necrosis factor inhibitors (TNFis) in patients with RA who were anti-cyclic citrullinated peptide antibody positive (anti-CCP+).

Methods

Abatacept or TNFi initiators with anti-CCP+ status (≥ 20 U/ml) at or prior to treatment initiation were identified from a large observational US cohort (1 December 2005–31 August 2016). Using propensity score matching (1:1), stratified by prior TNFi use (0, 1 and ≥ 2), effectiveness at 6 months after initiation was evaluated. Primary outcome was mean change in Clinical Disease Activity Index (CDAI) score. Secondary outcomes included achievement of remission (CDAI ≤ 2.8), low disease activity/remission (CDAI ≤ 10), modified American College of Rheumatology 20/50/70 responses and mean change in modified Health Assessment Questionnaire score.

Results

After propensity score matching, the baseline characteristics between 330 pairs of abatacept and TNFi initiators (biologic naïve, n = 97; TNFi experienced, n = 233) were well balanced with absolute value standardized differences of ≤ 0.1. Both overall, and in the biologic-naïve cohort, there were no significant differences in mean change in CDAI score at 6 months. However, in the TNFi-experienced cohort, there was a significantly greater improvement in CDAI score at 6 months with abatacept versus TNFi initiators (p = 0.033). Secondary outcomes showed similar trends.

Conclusions

Improvements in clinical disease activity were seen in anti-CCP+ abatacept and TNFi initiators. TNFi-experienced anti-CCP+ patients with RA had more improvement in disease activity with abatacept versus TNFis, whereas outcomes were similar between treatments in the overall population and in biologic-naïve patients.

Trial Registration

ClinicalTrials.gov identifier: NCT01625650.

Funding

This study is sponsored by Corrona, LLC and funded by Bristol-Myers Squibb. Bristol-Myers Squibb funded the publication of this manuscript.

Electronic supplementary material

The online version of this article (10.1007/s40744-019-0149-3) contains supplementary material, which is available to authorized users.

Bortezomib in antibody-mediated autoimmune diseases (TAVAB): study protocol for a unicentric, non-randomised, non-placebo controlled trial

INTRODUCTION

The clinical characteristics of autoantibody-mediated autoimmune diseases are diverse. Yet, medical treatment and the associated complications are similar, that is, the occurrence of long-term side effects and the problem that a significant proportion of patients are non-responders. Therefore, new therapeutic options are needed. Bortezomib, a proteasome inhibitor, is effective in the treatment of multiple myeloma and data from experimental models and case reports suggest an effect in the treatment of autoantibody-mediated autoimmunity. In our study, we will determine the effect of bortezomib treatment on a shared surrogate parameter for clinical efficacy, namely change in autoantibody levels, which we chose as primary parameter.

METHODS AND ANALYSIS

We designed a phase IIa trial with altogether n=18 treatment-refractory patients suffering from myasthenia gravis, systemic lupus erythematosus and rheumatoid arthritis that will be treated with bortezomib add-on to pre-existing therapy. Primary endpoint is the change in autoantibody levels 6 months after therapy. Secondary endpoints include concomitant medication, disease-specific clinical scores and measures of quality of life and activities of daily living.

ETHICS AND DISSEMINATION

Safety parameters include neurophysiological and clinical signs of peripheral neuropathy as well as potential central nervous system side effects determined by olfactory and neuropsychological testing. The study has been approved by the local ethical committee and first participants have already been enrolled. This proof of concept study will contribute to improve our understanding of plasma cell-specific treatment approaches by assessing its safety and efficacy in reducing serum levels of antibodies known to mediate autoimmune disorders.We plan to publish the final results of our study in a peer reviewed journal and to present our findings at international conferences.

TRIAL REGISTRATION NUMBER

NCT02102594.

Inflammatory arthritis and crystal arthropathy: Current concepts of skin and systemic manifestations

Systemic inflammatory disorders frequently involve the skin, and when cutaneous disease develops, such dermatologic manifestations may represent the initial sign of disease and may also provide valuable prognostic information about the underlying disorder. Familiarity with the various skin manifestations of systemic disease is therefore paramount and increases the likelihood of accurate diagnosis, which may facilitate the implementation of an appropriate treatment strategy. An improvement in quality of life and a reduction in the degree of morbidity may also be a realized benefit of accurate recognition of these skin signs. With this context in mind, this review highlights the salient clinical features and unique dermatologic manifestations of rheumatoid arthritis, adult-onset Still's disease, and the crystal arthropathy, gout.

Association of MTHFR C677T and A1298C gene polymorphisms with methotrexate efficiency and toxicity in Algerian rheumatoid arthritis patients

Methotrexate (MTX) is the most used drug in rheumatoid arthritis (RA) treatment. However, it shows variability in clinical response, which is explained by an association with genetic polymorphisms. This study aimed to elucidate the role of the two gene polymorphism C677T and A1298C of the methylenetetrahydrofolate reductase (MTHFR) in response to MTX in Algerian RA patients. Study included 54 early RA patient treated with MTX for one year. MTX efficiency and toxicity were evaluated at 6 and 12 months respectively and the two gene polymorphisms were genotyped. No association was found between A1298C polymorphism and MTX toxicity. However, T allele of the C677T polymorphism was associated with the occurrence of MTX adverse effects (p = 0,019, OR: 3,63, 95% CI [1,12 - 12,80]). No association was found between C677T polymorphism and MTX efficiency, while A allele of the A1298C polymorphism was associated with good and moderate response (p = 0,02, OR = 3,28, 95% CI: [1,11– 9,42]). The study of RA biological markers kinetics showed that MTX did not affect antibodies rate unlike inflammatory markers. Our study suggests that MTHFR C677T and A1298C genotyping are associated to MTX toxicity and efficiency, respectively, in RA patients. This offers new perspectives in the personalization of RA treatment in Algeria.

The Clinical Application of Anti-CCP in Rheumatoid Arthritis and Other Rheumatic Diseases

Rheumatoid arthritis (RA) is a common rheumatic disease in Caucasians and in other ethnic groups. Diagnosis is mainly based on clinical features. Before 1998, the only serological laboratory test that could contribute to the diagnosis was that for rheumatoid factor (RF). The disease activity markers for the evaluation of clinical symptoms or treatment outcome were the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). As a matter of fact, the diagnosis of early RA is quite impossible, as the clinical criteria are insufficient at the beginning stage of the disease. In 1998, Schelleken reported that a high percentage of RA patients had a specific antibody that could interact with a synthetic peptide which contained the amino acid citrulline. The high specificity (98%) for RA of this new serological marker, anti-cyclic citrullinated antibody (anti-CCP antibody), can be detected early in RA, before the typical clinical features appear. The presence or absence of this antibody can easily distinguish other rheumatic diseases from RA. Additionally, the titer of anti-CCP can be used to predict the prognosis and treatment outcome after DMARDs or biological therapy. Therefore, with improvement of sensitivity, the anti-CCP antibody will be widely used as a routine laboratory test in the clinical practice for RA.

Tumor necrosis factor-α blockade treatment decreased CD154 (CD40-ligand) expression in rheumatoid arthritis

Contexts

CD154 (commonly referred to as CD40-ligand) is a critical T cell factor that participates in the pathogenesis of autoimmune and is over-expressed in rheumatoid arthritis (RA). TNF-α blockade treatment had dramatic efficacy in RA.

Objective

To investigate whether TNF-α blockade treatment can inhibit CD154 expression in RA.

Methods

Blood samples were collected from 33 patients with rheumatoid arthritis before and 3 months after TNF-α blockade treatment. Clinical serological data determined by standard assays and T cell CD154 expression levels determined by flow cytometry were statistically analyzed for these two time points.

Results

The percentage of CD154 expression on gated CD4+ T cells of PBMCs from RA patients after 3 months TNF-α blockade treatment was significantly lower than before treatment (2.94 ± 3.21% vs. 7.21 ± 5.64%; p = 0.0001). The disease activity and anti-CCP antibody levels were also significantly reduced after TNF-α blockade treatment. The CD154 expression levels were positively correlated with disease activity index DAS28, and CRP. The post-stimulated CD154 expression percentage of purified CD4+ T cells between baseline and after TNF-α blockade treatment was not significantly different (p = 0.221). Baseline CD154 levels were positively correlated with treatment-induced changes in DAS28 (p = 0.014; r2 = 0.187).

Conclusions

TNF-α blockade treatment significantly decreased the CD154 expression on CD4+ T cells, disease activity and anti-CCP antibody simultaneously in RA patients. However TNF-α blockade did not impair T cell capacity to express CD154 after stimulation. These results suggest that decreased CD154 expression after TNF-α blockade may be due to decreased RA disease activity but not direct inhibition of CD154 responsiveness of T cells.

Transcriptional profiling of leukocytes from rheumatoid arthritis patients before and after anti-tumor necrosis factor therapy: A comparison of anti-nuclear antibody positive and negative subsets

Anti-nuclear antibodies (ANAs) may be induced in patients with rheumatoid arthritis (RA) receiving anti-tumor necrosis factor (TNF) therapy with TNF inhibitors (TNFi), etanercept, infliximab or adalimumab. In the present study, 11 patients who were TNFi drug naive were started on TNFi at a time of high disease activity. Of these, all cases were positive for rheumatoid factor and 9 cases tested were positive for anti-citrullinated peptide (anti-CCP) antibodies prior to TNFi treatment. Peripheral blood mononuclear cells (PBMCs) and serum were collected from all patients before and after TNFi therapy. Serum was assayed for ANAs over time. Total cellular RNA was extracted from PBMCs and assessed using Illumina arrays. Gene expression profiles were examined for alterations in key effector pathways. After 3 or more months on TNFi, 6 patients converted to ANA-positivity. Analysis of transcripts from patients with RA who converted to ANA-positivity after 3 months on TNFi identified complex gene expression profiles that reflected a reduction in cell adhesion, cell stress and lipid metabolism transcripts. In summary, unique transcriptional profiles in PBMCs from patients with RA were observed after TNFi therapy. This pilot study suggests that transcriptional profiling is a precise method of measuring the impact of TNFi therapies and reveals novel pathways that likely influence the immune response.

Effectiveness and safety of tocilizumab in achieving clinical and functional remission, and sustaining efficacy in biologics-naive patients with rheumatoid arthritis: The FIRST Bio study

OBJECTIVE

To evaluate effectiveness and safety of tocilizumab (TCZ) in biologic-naive Japanese patients with rheumatoid arthritis (RA) in real-world settings, and to analyze the relationship between disease duration and clinical outcomes.

METHODS

The FIRST Bio study was a postmarketing surveillance study of intravenous TCZ in biologics-naive patients who had a prior inadequate response or were intolerant to ≥1 conventional synthetic disease-modifying antirheumatic drug (csDMARD). Effectiveness, safety, and concomitant csDMARD administration were assessed.

RESULTS

Of the 839 patients analyzed, 72.3% completed 52 weeks of treatment. The Clinical Disease Activity Index (CDAI) remission rate at week 52 was 36.8%. Contributing factors for CDAI remission were younger age, early disease stage, and no comorbidities. Health Assessment Questionnaire Disability Index ≤0.5 was achieved in 65.1% of patients, and was significantly associated with disease duration. Discontinuation of concomitant methotrexate (MTX) and glucocorticoids (GCs) was possible in 19.3% and 34.1% of patients, respectively, without decreasing remission rate. The incidence (events/100 patient-years) of serious adverse events was 18.09, the most common being infection.

CONCLUSION

These data validate the importance of TCZ treatment in the early stages of RA in biologic-naive patients to achieve increased effectiveness. The safety profile of TCZ was reconfirmed. Furthermore, TCZ therapy may allow discontinuation of concomitant MTX and GCs without affecting remission.

A Contra Capture Protein Array Platform for Studying Post-translationally Modified (PTM) Auto-antigenomes

Aberrant modifications of proteins occur during disease development and elicit disease-specific antibody responses. We have developed a protein array platform that enables the modification of many proteins in parallel and assesses their immunogenicity without the need to express, purify, and modify proteins individually. We used anticitrullinated protein antibodies (ACPAs) in rheumatoid arthritis (RA) as a model modification and profiled antibody responses to ∼190 citrullinated proteins in 20 RA patients. We observed unique antibody reactivity patterns in both clinical anticyclic citrullinated peptide assay positive (CCP+) and CCP- RA patients. At individual antigen levels, we detected antibodies against known citrullinated autoantigens and discovered and validated five novel antibodies against specific citrullinated antigens (osteopontin (SPP1), flap endonuclease (FEN1), insulin like growth factor binding protein 6 (IGFBP6), insulin like growth factor I (IGF1) and stanniocalcin-2 (STC2)) in RA patients. We also demonstrated the utility of our innovative array platform in the identification of immune-dominant epitope(s) for citrullinated antigens. We believe our platform will promote the study of post-translationally modified antigens at a breadth that has not been achieved before, by both identifying novel autoantigens and investigating their roles in disease development. The developed platforms can potentially be used to study many autoimmune disease-relevant modifications and their immunogenicity.

Anti-citrullinated peptide antibodies and their value for predicting responses to biologic agents: a review

Anti-citrullinated peptide antibodies (ACPAs) play an important pathogenic role both at the onset and during the disease course. These antibodies precede the clinical appearance of rheumatoid arthritis (RA) and are associated with a less favorable prognosis, both clinically and radiologically. The objective of this work was to conduct a comprehensive review of studies published through September 2015 of ACPAs' role as a predictor of the therapeutic response to the biological agents in RA patients. The review also includes summary of the biology and detection of ACPAs as well as ACPAs in relation to joint disease and CV disease and the possible role of seroconversion. The reviews of studies examining TNF inhibitors and tocilizumab yielded negative results. In the case of rituximab, the data indicated a greater probability of clinical benefit in ACPA(+) patients versus ACPA(-) patients, as has been previously described for rheumatoid factor. Nonetheless, the effect is discreet and heterogeneous. Another drug that may have greater effectiveness in ACPA(+) patients is abatacept. Some studies have suggested that the drug is more efficient in ACPA(+) patients and that those patients show greater drug retention. In a subanalysis of the AMPLE trial, patients with very high ACPA titers who were treated with abatacept had a statistically significant response compared to patients with lower titers. In summary, the available studies suggest that the presence of or high titers of ACPA may predict a better response to rituximab and/or abatacept. Evidence regarding TNFi and tocilizumab is lacking. However, there is a lack of studies with appropriate designs to demonstrate that some drugs are superior to others for ACPA(+) patients.

Therapeutic implications of autoantibodies in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterised by the presence of autoantibodies. Their value for diagnostic/prognostic purposes has been well established. In contrast, their role in established disease and their associations with disease activity is less clear. Moreover, as evidence is accumulating that these autoantibodies are causally involved in certain key aspects of the disease, such as the initiation and perpetuation of joint inflammation or join destruction, autoantibodies in RA can no longer be regarded as mere epiphenomena, but are integral elements of the pathophysiology of RA.

A Personalized Approach to Biological Therapy Using Prediction of Clinical Response Based on MRP8/14 Serum Complex Levels in Rheumatoid Arthritis Patients

Objectives

Measurement of MRP8/14 serum levels has shown potential in predicting clinical response to different biological agents in rheumatoid arthritis (RA). We aimed to develop a treatment algorithm based on a prediction score using MRP8/14 measurements and clinical parameters predictive for response to different biological agents.

Methods

Baseline serum levels of MRP8/14 were measured in 170 patients starting treatment with infliximab, adalimumab or rituximab. We used logistic regression analysis to develop a predictive score for clinical response at 16 weeks. MRP8/14 levels along with clinical variables at baseline were investigated. We also investigated how the predictive effect of MRP8/14 was modified by drug type. A treatment algorithm was developed based on categorizing the expected response per drug type as high, intermediate or low for each patient and optimal treatment was defined. Finally, we present the utility of using this treatment algorithm in clinical practice.

Results

The probability of response increased with higher baseline MRP8/14 complex levels (OR = 1.39), differentially between the TNF-blockers and rituximab (OR of interaction term = 0.78), and also increased with higher DAS28 at baseline (OR = 1.28). Rheumatoid factor positivity, functional disability (a higher HAQ), and previous use of a TNF-inhibitor decreased the probability of response. Based on the treatment algorithm 80 patients would have been recommended for anti-TNF treatment, 8 for rituximab, 13 for another biological treatment (other than TNFi or rituximab) and for 69 no recommendation was made. The predicted response rates matched the observed response in the cohort well. On group level the predicted response based on the algorithm resulted in a modest 10% higher response rate in our cohort with much higher differences in response probability in individual patients treated contrary to treatment recommendation.

Conclusions

Prediction of response using MRP8/14 levels along with clinical predictors has potential in personalizing treatment for RA patients starting biological anti-rheumatic treatment, and might increase cost-effectiveness.

Cross-reactive and pre-existing antibodies to therapeutic antibodies--Effects on treatment and immunogenicity

The potential for immunogenicity is an ever-present concern during the development of biopharmaceuticals. Therapeutic antibodies occasionally elicit an antibody response in patients, which can result in loss of response or adverse effects. However, antibodies that bind a drug are sometimes found in pre-treatment serum samples, with the amount depending on drug, assay, and patient population. This review summarizes published data on pre-existing antibodies to therapeutic antibodies, including rheumatoid factors, anti-allotype antibodies, anti-hinge antibodies, and anti-glycan antibodies. Unlike anti-idiotype antibodies elicited by the drug, pre-formed antibodies in general appear to have little consequences during treatment. In the few cases where (potential) clinical consequences were encountered, antibodies were characterized and found to bind a distinct, unusual epitope of the therapeutic. Immunogenicity testing strategies should therefore always include a proper level of antibody characterization, especially when pre-formed antibodies are present. This minimizes false-positives, particularly due to rheumatoid factors, and helps to judge the potential threat in case a genuine pre-dose antibody reactivity is identified.

Circulating anti-citrullinated peptide antibodies, cytokines and genotype as biomarkers of response to disease-modifying antirheumatic drug therapy in early rheumatoid arthritis

Background

To measure circulating anti-citrullinated peptide antibodies (ACPA) and cytokines pre- and 6 months post-therapy as a strategy to predict and optimize responses to traditional disease-modifying antirheumatic drugs (DMARDs) in early RA, which is an unmet need in developing countries.

Patients and methods

A cohort of 140 predominantly (88.5 %) black female South African patients with early RA was treated with synthetic DMARDs, mostly methotrexate (MTX) alone, or in combination with low-dose oral corticosteroids (CS). Circulating ACPA and a panel of circulating cytokines/chemokines/growth factors were measured at baseline and after 6 months of therapy in relation to disease activity and Shared Epitope (SE).

Results

Following 6 months of therapy, the median simplified disease activity index (SDAI) declined from a baseline of 41.4 to 16.0 (p = 0.0001) for the entire cohort, which was paralleled by significant falls in median serum ACPA levels (516.6 vs. 255.7 units/ml, p = <0.0001) and several of the circulating cytokines (IL-4, IL-7, IL-8, G-CSF, VEGF; p < 0.0010 – p < 0.0001) which were most evident in the subgroup of patients treated with a combination of MTX and CS. Although biomarker concentrations decreased most notably in the low-disease activity group post-therapy, no significant correlations between these biomarkers and disease activity were observed, Baseline ACPA levels, but not SDAI or cytokines, were significantly higher in the subgroup of risk allele-positive patients (561.1 vs. 331.9 units/ml, p < 0.05), while no associations with ACPA and a smoking history were evident.

Conclusions

The use of DMARDs in RA is associated with significant decreases in ACPA and cytokines which did not correlate with changes in SDAI, precluding the utility of serial measurement of these biomarkers to monitor early responses to therapy, but may have prognostic value.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-015-0587-1) contains supplementary material, which is available to authorized users.

The Role of Posttranslational Protein Modifications in Rheumatological Diseases: Focus on Rheumatoid Arthritis

The definition of posttranslational modification (PTM) encompasses a wide group of chemical reactions that allow modification and modulation of protein functions. The regulation of PTMs is crucial for the activity and survival of the cells. Dysregulation of PTMs has been observed in several pathological conditions, including rheumatoid arthritis (RA). RA is a systemic autoimmune disease primarily targeting the joints. The three PTMs mainly involved in this disease are glycosylation, citrullination, and carbamylation. Glycosylation is essential for antigen processing and presentation and can modulate immunoglobulin activity. Citrullination of self-antigens is strongly associated with RA, as demonstrated by the presence of antibodies directed to anti-citrullinated proteins in patients' sera. Carbamylation and its dysregulation have been recently associated with RA. Aim of this review is to illustrate the most significant alterations of these PTMs in RA and to evaluate their possible involvement in the pathogenesis of the disease.

Clinical parameters and biomarkers for anti-TNF treatment prognosis in rheumatoid arthritis patients

Tumor necrosis factor (TNF) plays a pivotal role in the pathogenesis of rheumatoid arthritis (RA). This finding has led to the development of TNF blockers for RA treatment. However, response to these therapies is heterogeneous with success in only two thirds of patient. Some clinical aspects useful in the attempt to predict the response to TNF inhibitors is the promptness and the magnitude of the response at the first weeks and a low basal disease activity, while comorbidities, tobacco, glucocorticoids treatment, and high basal radiological score correlate with a poorer response. The role of TNF promoter polymorphisms in clinical response to anti-TNF therapies is controversial. A correlation between the presence of high baseline titers of rheumatoid factor (RF) and decreased response to anti-TNF treatment has been reported. Most studies show decreased RF titers during anti-TNF treatment mainly in patients who responded to treatment. There is no consensus about the usefulness of basal anti-citrullinated protein antibodies (ACPA) levels, and a decrease in ACPA titers as predictor of clinical response to anti-TNF therapy. Despite some promising markers identified to fulfill this role, currently the predictive value of single markers seems not strong enough to predict treatment response in an individual RA patient.

A metaanalysis of the increased risk of rheumatoid arthritis-related pulmonary disease as a result of serum anticitrullinated protein antibody positivity

OBJECTIVE

An inconsistent association has been reported between the serum anticitrullinated protein antibodies (ACPA) level and rheumatoid arthritis (RA)-related pulmonary disease risk. We conducted a metaanalysis to reveal the association between them.

METHODS

An electronic search was performed in PubMed, ScienceDirect, and SpringerLink databases for studies published up to August 2013. The distributions of the serum ACPA level in cases and controls were obtained from eligible studies. The risk of RA-related pulmonary disease associated with serum ACPA positivity was estimated by OR and 95% CI. According to the heterogeneity results, a fixed-effects model or a random-effects model was used to calculate the pooled OR. Publication bias and sensitivity analyses were conducted.

RESULTS

Overall, 243 patients with RA-related pulmonary disease and 1442 RA controls were included in the metaanalysis. The results showed that the pooled OR was 2.621 (95% CI, 1.561-4.403, p < 0.001) for the increased risk of RA-related pulmonary disease due to the serum ACPA positivity. In the white population subgroup, an increased OR was 3.453 (95% CI 1.798-6.630, p < 0.001), whereas no association was found in the Asian population subgroup. Additionally, we further revealed that serum ACPA positivity indicated a higher risk for interstitial lung disease (ILD) and interstitial pulmonary fibrosis (IPF) among patients with RA (OR 4.679, 95% CI 2.071-10.572, p < 0.001). The heterogeneity, publication bias, and sensitivity analyses had no statistical significance in any group.

CONCLUSION

To our knowledge, this is the first metaanalysis to reveal that serum ACPA positivity is highly associated with the risk of RA-related pulmonary disease, particularly in RA-related ILD and IPF.

Autoantibodies to posttranslational modifications in rheumatoid arthritis

Autoantibodies have been associated with human pathologies for a long time, particularly with autoimmune diseases (AIDs). Rheumatoid factor (RF) is known since the late 1930s to be associated with rheumatoid arthritis (RA). The discovery of anticitrullinated protein antibodies in the last century has changed this and other posttranslational modifications (PTM) relevant to RA have since been described. Such PTM introduce neoepitopes in proteins that can generate novel autoantibody specificities. The recent recognition of these novel specificities in RA provides a unique opportunity to understand human B-cell development in vivo. In this paper, we will review the three of the main classes of PTMs already associated with RA: citrullination, carbamylation, and oxidation. With the advancement of research methodologies it should be expected that other autoantibodies against PTM proteins could be discovered in patients with autoimmune diseases. Many of such autoantibodies may provide significant biomarker potential.

Abatacept reduces levels of switched memory B cells, autoantibodies, and immunoglobulins in patients with rheumatoid arthritis

OBJECTIVE

Abatacept (ABA) is a chimeric molecule, able to block the CD28-mediated costimulatory pathway. To evaluate the hypothesis that, through this mechanism of action, ABA may down-modulate the immune responses of B lymphocytes in rheumatoid arthritis (RA), we investigated the serum levels of immunoglobulins (Ig), free light chains (FLC), anticitrullinated protein antibodies (ACPA), and rheumatoid factor (RF), as well as the number of B lymphocytes differentiated into post-switch memory cells in patients treated with ABA.

METHODS

The serum levels of Ig, FLC, different ACPA, RF isotypes, and the B cell phenotype were longitudinally evaluated in 30 patients with RA treated with ABA.

RESULTS

At baseline, the proportion of total and post-switch memory B cells was lower in RA than in healthy individuals. After 6 months of ABA treatment we observed significant reductions of serum levels of IgG, IgA, and IgM, as well as FLC, with a normalization in many patients who had initially abnormal values. A significant reduction of the titers of IgG- and IgA-ACPA, as well as of IgM-, IgA-, and IgG-RF was also observed. A decrease of autoantibodies below the upper limits of normal values was found in 2 of 26 patients (8%) initially seropositive for IgG-ACPA, 1 of 14 (7%) for IgA-ACPA, 5 of 22 (23%) for IgM-RF, 7 of 22 (30%) for IgA-RF, and 5 of 16 (31%) for IgG-RF. After treatment, the proportion of circulating post-switch memory B cells was also further significantly decreased.

CONCLUSION

ABA treatment in patients with RA can reduce signs of polyclonal B cell activation, inducing a trend toward normalization of serum levels of different classes of Ig and of FLC, decreasing titers of ACPA and RF, and percentages of post-switch memory B cells.

Anticyclic citrullinated peptide antibody and rheumatoid factor in south Tunisian patients with rheumatoid arthritis: association with disease activity and severity

OBJECTIVE

To explore relationships between immunological status, clinical features, radiographic damage, disease activity, and functional disability in Tunisian patients with rheumatoid arthritis (RA).

MATERIALS AND METHODS

The study was carried out in 112 patients with RA. Demographic characteristics, disease duration, disease activity score 28 (DAS28), the Health Assessment Questionnaire (HAQ), and the Sharp/van der Heijde score were collected. Anticyclic citrullinated peptide antibody (anti-CCP) and rheumatoid factor (RF) were performed.

RESULTS

We found that anti-CCP positivity was associated with longer disease duration (P = 0.001), presence of RF (P = 4.89 × 10(-8) ), and night pain positivity (P = 0.025). Patients with positive RF had more night pain and higher anti-CCP positivity (for all P ≤ 0.05). Anti-CCP titer was correlated with disease duration (P = 0.034) and Sharp total score (P = 1.2 × 10(-4) ). Moreover, there was a significant correlation between RF and anti-CCP antibodies titers (P = 0.011). Indeed, DAS28 correlated with HAQ (P = 1.8 × 10(-7) ) and morning stiffness duration (P = 0.045). In multivariate regression analysis, the main factors associated with anti-CCP titers were radiographic damage (P = 1.625 × 10(-4) ) and RF (P = 0.013). For DAS28, only HAQ (P = 2.9 × 10(-4) ) was associated.

CONCLUSION

These findings suggest that anti-CCP antibodies are associated with RF and more severe joint damage. Moreover, disease activity is associated with functional disability.

Predictors of response and remission in a large cohort of rheumatoid arthritis patients treated with tocilizumab in clinical practice

OBJECTIVE

The objective of this study was to identify predictors of response and remission to tocilizumab (TCZ) in RA patients seen in daily routine clinical practice.

METHODS

The efficacy of TCZ was evaluated after 12 and 24 weeks of treatment by the European League Against Rheumatism (EULAR) response criteria. Regression analysis was performed to study the association between remission or EULAR response and the following characteristics: gender, age, current smokers, prior cardiovascular disease (CVD), 28-joint disease activity score (DAS28), CRP, RF or ACPA positivity, combination therapy with DMARDs and TCZ as the first biological therapy or after failure of at least one biological therapy.

RESULTS

In total, 204 patients were included with a mean DAS28 score of 5.14. EULAR response and remission were obtained in 86.1% and 40% of patients, respectively, at week 24. In multiple regression analysis, a high baseline CRP level [odds ratio (OR) 4.454 (95% CI 1.446, 13.726)] was significantly associated with EULAR response at week 24 and, inversely, age >55 years [OR 0.285 (95% CI 0.086, 0.950)] and prior CVD [OR 0.305 (95% CI 0.113, 0.825)] were significantly associated with lower EULAR response at week 24. Older age was also associated with less remission at week 24 [OR 0.948 (95% CI 0.920, 0.978)]. No additional effectiveness was found when TCZ was used in combination with a DMARD or when patients were naive to biological agents.

CONCLUSION

In daily practice we identified three predictors of a better response for TCZ therapy in RA: a younger age, a high baseline CRP level and no history of CVD.

Plasma level of neopterin as a marker of disease activity in treated rheumatoid arthritis patients: association with gender, disease activity and anti-CCP antibody

Immune system activation is known to be involved in the progression of rheumatoid arthritis (RA). The pro-inflammatory cytokine interferon-γ in various cells, including monocytes, induces neopterin production. Plasma level of neopterin has been measured in many autoimmune diseases and can be used as a marker of cellular immunity activation. In this study we measured the plasma level of neopterin in 418 treated RA patients and 398 age and sex matched healthy people by high pressure liquid chromatography (HPLC) method. Disease activity score was calculated in all patients by DAS-CRP method. Plasma level of neopterin was compared between RA and control groups. We also determined the association between neopterin level with gender and disease activity score in RA patients. Significantly higher level of neopterin was observed in RA patients compared to healthy controls. Moreover, there was higher neopterin level in male RA patients versus female patients. Plasma neopterin level was increased in patients with active disease and also was correlated with disease activity parameters. There was a significant correlation of plasma level of neopterin with age in both RA and control group and also age of onset and disease duration in RA patients. Anti-CCP positive patients had higher level of neopterin in comparison to anti-CCP negative patients and there was a significant correlation between neopterin level and anti-CCP titer. Our results indicated that neopterin is a sensitive marker for assaying background inflammation and disease activity score in RA patients and may be used as a marker for evaluation of therapy efficacy.

The effect of targeted rheumatoid arthritis therapies on anti-citrullinated protein autoantibody levels and B cell responses

Rheumatoid arthritis (RA) is a complex inflammatory disorder associated with synovitis and joint destruction that affects an estimated 1·3 million Americans and causes significant morbidity, a reduced life-span and lost work productivity. The use of biological therapies for the treatment of RA is costly, and the selection of therapies is still largely empirical and not guided by the underlying biological features of the disease in individual patients. The synovitis associated with RA is characterized by an influx of B and T cells, macrophages and neutrophils and the expansion of fibroblast-like synoviocytes, which form pannus and lead to cartilage and bone destruction. RA is associated with synovial production of rheumatoid factor (RF) and anti-citrullinated protein autoantibodies (ACPA) and with the production of inflammatory cytokines, including interleukin (IL)-1, IL-6, IL-17 and tumour necrosis factor (TNF)-α, which are targets for RA therapeutics. Recent ideas about the pathogenesis of RA emphasize a genetic predisposition to develop RA, a preclinical phase of disease that is associated with the production of ACPA and the development of symptomatic disease following inflammatory initiating events that are associated with expression of citrullinated epitopes in the joints of patients. However, we still have a limited understanding of the cytokine and intracellular pathways that regulate ACPA levels. In humans, therapy with biological agents affords a unique opportunity to better understand the cytokine and signalling pathways regulating ACPA levels and the impact of ACPA level changes on disease activity. In this study we summarize the effect of RA therapies on ACPA levels and B cell responses.

Cross-linking of IgGs bound on circulating neutrophils leads to an activation of endothelial cells: possible role of rheumatoid factors in rheumatoid arthritis-associated vascular dysfunction

BACKGROUND

Rheumatoid arthritis is characterized by the presence of circulating auto-antibodies, including rheumatoid factors, which recognize the Fc portion of IgGs. The neutrophil is the most abundant circulating leukocyte and it expresses high levels of FcγRs on its surface. The aim of the present study was to examine the capacity of circulating human neutrophils to be activated by rheumatoid factors and the consequences of these events on endothelium.

METHODS

Neutrophil-bound IgGs were cross-linked with anti-human IgGs to mimick the presence of circulating rheumatoid factors and FcγRs-dependent signalling events and functions were examined. The IgG and IgM composition of rheumatoid factors isolated from the serum of RA patients was characterized. Adhesion of neutrophils to endothelial cells was quantified in response to the addition of rheumatoid factors.

RESULTS

Cross-linking of IgGs bound on neutrophils leads to FcγRs-dependent tyrosine phosphorylation, mobilisation of intracellular calcium and the extracellular release of superoxide anions and lysozyme. Incubation of endothelial cells with the supernatant of activated neutrophils increases ICAM-1 expression and IL-8 production by endothelial cells. Finally, rheumatoid factors enhance neutrophil adhesion to endothelial cells.

CONCLUSIONS

Our results show that activation of neutrophils' FcγRs by rheumatoid factors could participate in rheumatoid arthritis-associated vascular damage.

Rheumatoid factor and response to TNF antagonists in rheumatoid arthritis: systematic review and meta-analysis of observational studies

OBJECTIVE

To systematically analyze literature with the aim of examining whether rheumatoid factor (RF) is a predictor of response to tumor necrosis factor (TNF) antagonists in rheumatoid arthritis (RA).

METHODS

A systematic review and meta-analysis of observational studies were conducted. All studies on the association of baseline RF (titer and/or status) and response to any TNF antagonists, or with enough information to estimate this association were included. Qualitative analysis and meta-analysis using random-effects approach by type of outcome response and RF test was performed. Risk of publication bias was also evaluated.

RESULTS

The systematic review included 18 studies of 4163 identified articles, involving 5703 patients with homogeneous baseline characteristics. The most common outcome to assess response was European League Against Rheumatism (EULAR) response criteria, normally merging good and moderate categories as response. The weighted mean difference (WMD) of baseline IgM RF titer in meta-analysis was higher in the non-responders group [-101.58 (95% CI -156.58,-46.59) I2=0.0]. Combined odds ratios (ORs) of positive IgM RF, positive IgA RF, and positive IgG RF to achieve good/moderate response were 1.08 (0.80, 1.47), I2=40.9%; 0.83 (0.39, 1.73), I2=39.8%, and 1.30 (0.48, 3.51), I2=62.9%, respectively. We did not find an association between a positive IgM RF and EULAR good response or remission.

CONCLUSIONS

This meta-analysis does not support baseline IgM RF titer as a predictor of response to TNF antagonists in RA. However, this conclusion is hampered by high heterogeneity in the studies included in this meta-analysis.

Higher levels of autoantibodies targeting mutated citrullinated vimentin in patients with psoriatic arthritis than in patients with psoriasis vulgaris

Antibodies against citrullinated proteins/peptides (ACPAs), and especially antibodies targeting mutated citrullinated vimentin (anti-MCVs), are novel biomarkers of rheumatoid arthritis (RA). Whereas ACPAs are specific and sensitive markers for RA, there have hardly been any reports relating to ACPAs in psoriatic arthritis (PsA) or in psoriasis without joint symptoms (PsO). The aim of the present study was to investigate the prevalence of anti-MCVs in PsA and PsO. Serum anti-MCV titers were measured in 46 PsA and 42 PsO patients and in 40 healthy controls by means of a commercial enzyme-linked immunosorbent assay. The potential correlations of the serum autoantibody levels with several clinical and laboratory parameters were examined. The anti-MCV levels in the PsA patients were significantly higher than those in the PsO group. Among the clinical variables, the presence of tender knee joints and nail psoriasis was significantly associated with anti-MCV positivity in the PsA patients. Higher anti-MCV titers in the PsO patients were associated with a more severe disease course and with the early onset of psoriatic skin symptoms. Our results suggest that anti-MCVs can be used as novel markers in the diagnosis of PsA and in a subset of PsO patients.