The effect of etanercept on anti-cyclic citrullinated peptide antibodies and rheumatoid factor in patients with rheumatoid arthritis

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.

Prevalence and predictors of atlanto-axial subluxation in rheumatoid arthritis after 12-years' follow-up (ESPOIR Cohort)

OBJECTIVES

Anterior atlanto-axial subluxation (AAS), defined as an anterior atlanto-dental interval ≥3 mm, can occur in RA and carries a risk of severe neurological impairments. Our objective was to determine the prevalence and predictors of radiographic aAAS after 12 years' follow-up of patients with early polyarthritis.

METHODS

We studied patients enrolled in the early polyarthritis cohort ESPOIR (Study and Monitoring of Early Undifferentiated Arthritis) between 2002 and 2005 (at least two swollen joints for >6 weeks and <6 months, no other diagnosis than RA, and no previous exposure to glucocorticoids or DMARDs). All patients still in the cohort after 12 years had dynamic cervical-spine radiographs taken then read by two blinded observers. To evaluate how well combinations of tests performed at baseline and 10 years predicted aAAS after 12 years, univariate analysis and multiple logistic regression procedure were applied.

RESULTS

Of 323 patients followed for 12 years, 15 (4.6%; 95% CI 2.8, 6.4) had aAAS. Among baseline variables, only IgA RFs were associated (P < 0.05) with aAAS (sensitivity 60%, specificity 75%). Among data collected after 10 years, oral CS therapy during the 10-year interval, treatment by DMARDs, CRP (mg/dl) and positive tests for RFs were associated with aAAS after 12 years, but only CRP and RFs remained in a model of logistic regression (combination predicted aAAS with a sensitivity of 60% for a specificity of 90%).

CONCLUSION

In conclusion, the prevalence of aAAS after 12 years was 4.6% in the ESPOIR cohort, with no patients having severe aAAS. Although some factors were found to be statistically associated to AAS, the event is too rare to allow a clinical relevance.

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.

Association of tumor necrosis factor-alpha promoter region gene polymorphism at positions -308G/A, -857C/T, and -863C/A with etanercept response in Iraqi rheumatoid arthritis patients

Objectives

This study aims to evaluate the association between polymorphisms in the promoter region of the tumor necrosis factor-alpha (TNF-α) gene at locations -308G/A, -857C/T, and -863C/A with the tendency of being non-responder to etanercept.

Patients and methods

Between October 2020 and August 2021, a total of 80 patients (10 males, 70 females; mean age: 50 years; range, 30 to 72 years) with rheumatoid arthritis (RA) receiving etanercept for at least six months were included. The patients were divided into two groups responders and non-responders, based on their response after six months of continuous treatment. Following polymerase chain reaction amplification of the extracted deoxyribonucleic acid, sequencing by Sanger method was performed to identify the polymorphism at the TNF-α promoter region.

Results

In the responder group, the GG genotype of (-308G/A) and the AA genotype of (-863C/A) were both significantly present. The CC genotype of (-863C/A) was significantly present in the non-responders group. The CC of (-863C/A) SNP was the only genotype that appeared to increase the likelihood of being resistant to etanercept. The GG genotype of (-308G/A) was negatively correlated with the likelihood of being a non-responder. The (-857CC) and (-863CC) genotypes were significantly more prevalent in the non-responders group.

Conclusion

The presence of the (-863CC) genotype, alone or in combination with (-857CC), is linked to an increased likelihood of becoming a non-responder to etanercept. The GG genotype of -308G/A and the AA genotype of -863C/A significantly increase the likelihood of becoming responder to etanercept.

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.

Citrullination in the pathology of inflammatory and autoimmune disorders: recent advances and future perspectives

Numerous post-translational modifications (PTMs) govern the collective metabolism of a cell through altering the structure and functions of proteins. The action of the most prevalent PTMs, encompassing phosphorylation, methylation, acylations, ubiquitination and glycosylation is well documented. A less explored protein PTM, conversion of peptidylarginine to citrulline, is the subject of this review. The process of citrullination is catalysed by peptidylarginine deiminases (PADs), a family of conserved enzymes expressed in a variety of human tissues. Accumulating evidence suggest that citrullination plays a significant role in regulating cellular metabolism and gene expression by affecting a multitude of pathways and modulating the chromatin status. Here, we will discuss the biochemical nature of arginine citrullination, the enzymatic machinery behind it and also provide information on the pathological consequences of citrullination in the development of inflammatory diseases (rheumatoid arthritis, multiple sclerosis, psoriasis, systemic lupus erythematosus, periodontitis and COVID-19), cancer and thromboembolism. Finally, developments on inhibitors against protein citrullination and recent clinical trials providing a promising therapeutic approach to inflammatory disease by targeting citrullination are discussed.

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.

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.

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.

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.

Detection of IL-37 in peripheral blood of patients with rheumatoid arthritis and its clinical significance

The study aimed to detect the expression level of interleukin-37 (IL-37) in patients with rheumatoid arthritis (RA) and explore its clinical significance. A total of 40 peripheral blood samples from active and stable RA patients were collected (40 patients with RA), and peripheral blood from 40 healthy volunteers was used as the control group. Peripheral blood serum and peripheral blood mononuclear cells (PBMCs) were isolated. The expression of IL-37 mRNA in PBMCs was detected by real-time fluorescence quantitative PCR. Serum levels of IL-37, rheumatoid factor (RF), and anticyclic citrullinated peptide antibody (CCP) were measured by enzyme-linked immunosorbent assay (ELISA). The results were then calculated and analyzed. The results showed that expression of IL-37 mRNA in the PBMCs of patients with RA was significantly higher than that in the control group ( P < 0.05). Expression of IL-37 mRNA in the PBMCs of the active period group was significantly higher than that in the stable period group ( P < 0.05). IL-37 levels in patients with RA were significantly higher than those of the control group ( P < 0.05). IL-37 levels in the active period group were also significantly higher than those of the stable period group ( P < 0.05). The comparative analysis of RF and anti-CCP antibody levels showed that IL-37 was positively correlated with RF and anti-CCP levels in patients with RA. In conclusion, the expression level of IL-37 in peripheral blood of RA patients was significantly higher than that of normal control group, and it was correlated with RF and CCP antibody levels, indicating that IL-37 plays an important role in the development of RA.

Anti-CCP-positive patients with RA have a higher 10-year probability of fracture evaluated by FRAX®: a registry study of RA with osteoporosis/fracture

Background

Positive anticyclic citrullinated peptide (anti-CCP+) is associated with bone loss in patients with rheumatoid arthritis (RA). However, whether overall positivity or specific levels of anti-CCP are associated with prevalent fracture or a 10-year probability of fracture remains unclear.

Methods

This interim analysis of an RA registry was conducted at Chang Gung Memorial Hospital in Kaohsiung (CGMHK) for RA-related osteoporosis/fracture. Consecutive patients with RA who had visited the rheumatology clinic at CGMHK since September 1, 2014, and fulfilled the classification criteria of RA were enrolled. The demographics, disease duration, Disease activity in 28 joints based on erythrocyte sedimentation rate (DAS28-ESR), lifestyle, evidence of previous fracture, risk factors of fracture in the Fracture Risk Assessment Tool (FRAX®), and FRAX® score of each participant were collected. Anti-CCP, rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and bone mineral density (BMD) were measured at enrollment. The patients were grouped by positivity or quartiles of anti-CCP level (I–IV).

Results

Five hundred twenty-one patients with RA were enrolled through May 31, 2016. In total, 359 (68.9%) patients were anti-CCP+. Compared with anti-CCP− patients, anti-CCP+ patients had a significantly higher DAS28-ESR (p = 0.0001) and 10-year probability of major (15.0 [18.9] vs. 12.0 [15.3], p = 0.0461) or hip (5.0 [9.2] vs. 3.6 [8.2], p = 0.0118) fracture, but a significantly lower BMD of the FN (p = 0.0196). The rates of osteoporosis and previous fracture were comparable. There were 130, 127, 132, and 132 patients in groups I–IV, respectively. The DAS28-ESR was significantly different (p = 0.0001) among the groups and correlated to anti-CCP levels. The BMD and 10-year probability of major (p = 0.0067) and hip (p = 0.0013) fracture among the groups were also different.

Conclusions

Anti-CCP+ RA patients had a higher 10-year probability of major or hip fracture, independent of anti-CCP levels, and a lower BMD of the FN than anti-CCP− patients.

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.

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.

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.

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 comparative safety of tumor necrosis factor inhibitors in rheumatoid arthritis: a meta-analysis update of 44 trials

OBJECTIVE

The study objective was to evaluate and update the safety data from randomized controlled trials of tumor necrosis factor inhibitors in patients treated for rheumatoid arthritis.

METHODS

A systematic literature search was conducted from 1990 to May 2013. All studies included were randomized, double-blind, controlled trials of patients with rheumatoid arthritis that evaluated adalimumab, certolizumab pegol, etanercept, golimumab, or infliximab treatment. The serious adverse events and discontinuation rates were abstracted, and risk estimates were calculated by Peto odds ratios (ORs).

RESULTS

Forty-four randomized controlled trials involving 11,700 subjects receiving tumor necrosis factor inhibitors and 5901 subjects receiving placebo or traditional disease-modifying antirheumatic drugs were included. Tumor necrosis factor inhibitor treatment as a group was associated with a higher risk of serious infection (OR, 1.42; 95% confidence interval [CI], 1.13-1.78) and treatment discontinuation due to adverse events (OR, 1.23; 95% CI, 1.06-1.43) compared with placebo and traditional disease-modifying antirheumatic drug treatments. Specifically, patients taking adalimumab, certolizumab pegol, and infliximab had an increased risk of serious infection (OR, 1.69, 1.98, and 1.63, respectively) and showed an increased risk of discontinuation due to adverse events (OR, 1.38, 1.67, and 2.04, respectively). In contrast, patients taking etanercept had a decreased risk of discontinuation due to adverse events (OR, 0.72; 95% CI, 0.55-0.93). Although ORs for malignancy varied across the different tumor necrosis factor inhibitors, none reached statistical significance.

CONCLUSIONS

These meta-analysis updates of the comparative safety of tumor necrosis factor inhibitors suggest a higher risk of serious infection associated with adalimumab, certolizumab pegol, and infliximab, which seems to contribute to higher rates of discontinuation. In contrast, etanercept use showed a lower rate of discontinuation. These data may help guide clinical comparative decision making in the management of rheumatoid arthritis.

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.

Restoration of peripheral blood natural killer and B cell levels in patients affected by rheumatoid and psoriatic arthritis during etanercept treatment

Etanercept (ETN) is an anti-tumour necrosis factor (TNF)-α agent used in rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Few studies focused on the effects of anti-TNF-α on peripheral blood cells. We aimed to evaluate peripheral blood cells in RA and PsA patients during ETN treatment and to explore their relationships with disease activity. RA (n = 82) and PsA (n = 32) patients who started ETN were included into the study and evaluated prospectively before the beginning of ETN therapy and after 14, 22, 54 and 102 weeks. Patients were studied in terms of disease activity score on 28 joints (DAS28), clinical response and laboratory findings. Natural killer (NK) cells, B cells and T cells were characterized by immunophenotyping. Both the RA and the PsA patients showed reduced NK and B cell count before ETN treatment compared with controls. A negative correlation was demonstrated between DAS28 and B cell count in RA patients at baseline. Sustained significant increase of NK and B cells up to normal levels was observed in RA and PsA patients along ETN treatment. Increase of NK cell count was associated with a good-moderate clinical response to ETN in both RA and PsA patients. During ETN treatment peripheral blood NK and B cells levels were restored in RA and PsA patients. Correlations between NK and B cells with disease activity were observed, suggesting that those effects could be mediated by ETN treatment.

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.

Rheumatoid factors: clinical applications

Rheumatoid factors are antibodies directed against the Fc region of immunoglobulin G. First detected in patients with rheumatoid arthritis 70 years ago, they can also be found in patients with other autoimmune and nonautoimmune conditions, as well as in healthy subjects. Rheumatoid factors form part of the workup for the differential diagnosis of arthropathies. In clinical practice, it is recommended to measure anti-cyclic citrullinated peptide antibodies and rheumatoid factors together because anti-cyclic citrullinated peptide antibodies alone are only moderately sensitive, and the combination of the two markers improves diagnostic accuracy, especially in the case of early rheumatoid arthritis. Furthermore, different rheumatoid factor isotypes alone or in combination can be helpful when managing rheumatoid arthritis patients, from the time of diagnosis until deciding on the choice of therapeutic strategy.

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.

Etanercept for the treatment of rheumatoid arthritis

BACKGROUND

Etanercept is a soluble tumour necrosis factor alpha-receptor disease-modifying anti-rheumatic drug (DMARD) for the treatment of rheumatoid arthritis (RA).

OBJECTIVES

The purpose of this review was to update the previous Cochrane systematic review published in 2003 assessing the benefits and harms of etanercept for the treatment of RA. In addition, we also evaluated the benefits and harms of etanercept plus DMARD compared with DMARD monotherapy in those people with RA who are partial responders to methotrexate (MTX) or any other traditional DMARD.

SEARCH METHODS

Five electronic databases were searched from 1966 to February 2003 with no language restriction. The search was updated to January 2012. Attempts were made to identify other studies by contact with experts, searching reference lists and searching trial registers.

SELECTION CRITERIA

All controlled trials (minimum 24 weeks' duration) comparing four possible combinations: 1) etanercept (10 mg or 25 mg twice weekly) plus a traditional DMARD (either MTX or sulphasalazine) versus a DMARD, 2) etanercept plus DMARD versus etanercept alone, 3) etanercept alone versus a DMARD or 4) etanercept versus placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias of the trials.

MAIN RESULTS

Three trials were included in the original version of the review. An additional six trials, giving a total of 2842 participants, were added to the 2012 update of the review. The trials were generally of moderate to low risk of bias, the majority funded by pharmaceutical companies. Follow-up ranged from six months to 36 months.BenefitAt six to 36 months the American College of Rheumatology (ACR) 50 response rate was statistically significantly improved with etanercept plus DMARD treatment when compared with a DMARD in those people who had an inadequate response to any traditional DMARD (risk ratio (RR) 2.0; 95% confidence interval (CI) 1.3 to 2.9, absolute treatment benefit (ATB) 38%; 95% CI 13% to 59%) and in those people who were partial responders to MTX (RR 11.7; 95% CI 1.7 to 82.5, ATB 36%). Similar results were observed when pooling data from all participants (responders or not) (ACR 50 response rates at 24 months: RR 1.9; 95% CI 1.3 to 2.8, ATB 29%; 36 months: RR 1.6; 95% CI 1.3 to 1.9, ATB 24%). Statistically significant improvement in physical function and a higher proportion of disease remission were observed in combination-treated participants compared with DMARDs alone ((mean difference (MD) -0.36; 95% CI -0.43 to -0.28 in a 0-3 scale) and (RR 1.92; 95% CI 1.60 to 2.31), respectively) in those people who had an inadequate response to any traditional DMARD. All changes in radiographic scores were statistically significantly less with combination treatment (etanercept plus DMARD) compared with MTX alone for all participants (responders or not) (Total Sharp Score (TSS) (scale = 0 to 448): MD -2.2, 95% CI -3.0 to -1.4; Erosion Score (ES) (scale = 0 to 280): MD -1.6; 95% CI -2.4 to -0.9; Joint Space Narrowing Score (JSNS) (scale = 0 to 168): MD -0.7; 95% CI -1.1 to -0.2), and with combination treatment compared with etanercept alone (TSS: MD -1.1; 95% CI -1.8 to -0.5; ES: MD -0.7; 95% CI -1.1 to -0.2; JSNS: MD -0.5, 95% CI -0.7 to -0.2). The estimate of irreversible physical disability over 10 years given the radiographic findings was 0.45 out of 3.0.When etanercept monotherapy was compared with DMARD monotherapy, there was generally no evidence of a difference in ACR50 response rates when etanercept 10 mg or 25 mg was used; at six months etanercept 25 mg was significantly more likely to achieve ACR50 than DMARD monotherapy but this difference was not found at 12, 24 or 36 months. TSS and ES radiographic scores were statistically significantly improved with etanercept 25 mg monotherapy compared with DMARD (TSS: MD -0.7; 95% CI -1.4 to 0.1; ES: MD -0.7; 95% CI -1.0 to -0.3) but there was no evidence of a statistically significant difference between etanercept 10 mg monotherapy and MTX.HarmsThere was no evidence of statistically significant differences in infections or serious infections between etanercept plus DMARD and DMARD alone at any point in time. Infection rates were higher in people receiving etanercept monotherapy compared with DMARD; however, there were no differences regarding serious infections. For those participants who had an inadequate response to DMARDs, the rate of total withdrawals was lower for the etanercept plus DMARD group compared with DMARD alone (RR 0.53; 95% CI 0.36 to 0.77, ATB 18%). No other statistically significant differences were observed in any of the assessed comparisons.

AUTHORS' CONCLUSIONS

Etanercept 25 mg administered subcutaneously twice weekly together with MTX was more efficacious than either etanercept or MTX monotherapy for ACR50 and it slowed joint radiographic progression after up to three years of treatment for all participants (responders or not). There was no evidence of a difference in the rates of infections between groups.

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.

Serological changes in the course of traditional and biological disease modifying therapy of rheumatoid arthritis

OBJECTIVE

To investigate changes of rheumatoid factor (RF) and antibodies against citrullinated peptides (ACPA) during therapy with disease modifying antirheumatic drugs.

METHODS

We obtained clinical and serological data of patients from the treatment start and after 6 months of therapy. With non-parametric tests, we analysed changes of ACPA and RF levels between the two visits and the influence of treatment response. Furthermore, we analysed potential influential factors as disease chronicity, different therapeutics and the trend over 18 months.

RESULTS

143 ACPA and RF positive patients were included. The median (25th/75th percentile) relative changes after 6 months were -35.6% (-63.3; -8.3) for RF and -15.2% (-40.0; 10.0) for ACPA (p<0.001 for both). Changes of RF levels were significantly greater than those seen for ACPA (p<0.001). The decrease of ACPA and RF was significantly higher in treatment responders (p=0.034 and p=0.01, respectively). Aside from changes in disease activity, only a short disease duration showed an independent effect on changes of RF levels (p=0.087).

CONCLUSIONS

ACPA and RF levels decreased significantly after 6 months of therapy. Reductions of both autoantibodies were closely linked to a reduction of disease activity. RF declined faster, to a larger extent and in greater numbers of patients than ACPA.

Serum anti-cyclic citrullinated peptide antibodies may predict disease activity in rheumatoid arthritis

To define the relationship between serum anti-cyclic citrullinated peptide antibodies (anti-CCP) and disease activity, and to construct a new disease activity index by using anti-CCP in rheumatoid arthritis (RA). One hundred and five RA patients were included. Disease activity based on DAS28-ESR and serum anti-CCP was measured. There was correlation between serum anti-CCP and DAS28-ESR. (R (2) = 0.71, P value < 0.01). New disease activity index was developed by replacing anti-CCP with ESR in DAS28-ESR. There was correlation between new model and DAS28-ESR. (R (2) = 0.91, P value < 0.01) The new composite index best cut-off values corresponding to DAS28-ESR values of 2.6, 3.2, and 5.1 were 3.21, 3.38, and 4.74, respectively. There was agreement between new model and DAS28-ESR for determination of patients in different disease activity categories. (Kappa = 0.71, P value < 0.01). The new disease activity index that applies serum anti-CCP may predict disease activity in RA.

The effectiveness of Echinacea extract or composite glucosamine, chondroitin and methyl sulfonyl methane supplements on acute and chronic rheumatoid arthritis rat model

The study aimed to investigate the effect of the oral administration for 15 days of either Echinacea (E) or genuphil (a composite of chondroitin sulphate, glucosamine and methyl sulfonyl methane [GCM]) nutraceutical supplements on female rat model of acute or chronic arthritis induced by bacterial outer membrane protein (OMP) from faecal flora of healthy and rheumatic humans. Anti-cyclic citrullinated peptide (anti-CCP2), C-reactive protein (CRP) and rheumatoid factor (RF) values increased ( p < 0.05) in both arthritic groups as compared to normal values. The rheumatic markers anti-CCP2, CRP and RF values decreased significantly in E- and GCM-treated groups compared to arthritic none-treated acute or chronic groups. The results of RF values of GCM-treated groups in acute and chronic models decreased exhibiting no statistical difference compared with the normal value. Histological examinations of the hind paw sections revealed moderate inflammation, oedema and mild proliferation of synovial cells in acute arthritic rats and more damage to cartilage and bone with severe inflammation in chronic ones. Echinacea acute treated group showed edema with proliferated synovial membrane and partial damage in cartilage and bone. While in the E -chronic treated group, rough edge with destructed cartilage and bone existed. However, the acute GCM group revealed mild cartilage damage. But the chronic GCM group showed mild synovial cells proliferation and revealed no inflammation with mild cartilage damage edge. Results demonstrated the OMP arthropathic property and through promising light on arthritis treatment using E- or GCM, with the advantage of GMC results over that of E -. The composite GCM is needed for further studies over the dose and duration to assess its preventive effects against the bacterial OMP arthrogenicity.

Antibodies to citrullinated protein antigens (ACPAs): clinical and pathophysiologic significance

Antibodies to citrullinated protein antigens (ACPAs) are highly specific for rheumatoid arthritis (RA) and are useful in the diagnosis of RA as well as the prediction of the course and outcomes of disease. Multiple methodologies exist for measuring ACPAs, including the widely available tests for anticyclic citrullinated peptide antibodies and for antibodies to mutated/modified citrullinated vimentin. These methodologies overall have similar diagnostic accuracies for RA, although there is some variability. The discovery of ACPAs and the biology of citrullination have also led to important advances in the understanding of the pathophysiology and development of RA, especially regarding the relationship between potential genetic and environmental risk factors for RA. Going forward, research into autoimmunity to citrullinated proteins may help identify the specific etiology of RA and provide approaches for the prediction of future risk of disease, and ultimately prevention of RA.

A systematic review of serum biomarkers anti-cyclic citrullinated Peptide and rheumatoid factor as tests for rheumatoid arthritis

This systematic review assesses the current status of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) tests in the diagnosis and prognosis of rheumatoid arthritis (RA). We reviewed publications on tests and biomarkers for early diagnosis of RA from English-language MEDLINE-indexed journals and non-MEDLINE-indexed sources. 85 publications were identified and reviewed, including 68 studies from MEDLINE and 17 non-MEDLINE sources. Anti-CCP2 assays provide improved sensitivity over anti-CCP assays and RF, but anti-CCP2 and RF assays in combination demonstrate a positive predictive value (PPV) nearing 100%, greater than the PPV of either of the tests alone. The combination also appears to be able to distinguish between patients whose disease course is expected to be more severe and both tests are incorporated in the 2010 ACR Rheumatoid Arthritis Classification Criteria. While the clinical value of anti-CCP tests has been established, differences in cut-off values, sensitivities and specificities exist between first-, second- and third-generation tests and harmonization efforts are under way. Anti-CCP and RF are clinically valuable biomarkers for the diagnosis and prognosis of RA patients. The combination of the two biomarkers in conjunction with other clinical measures is an important tool for the diagnosis and management of RA patients.

The presence of anti-citrullinated protein antibodies (ACPA) does not affect the clinical response to adalimumab in a group of RA patients with the tumor necrosis factor (TNF) α-308 G/G promoter polymorphism

The introduction of antitumor necrosis factor (TNF) agents has improved the outcome for many patients with rheumatoid arthritis (RA). To date, the only replicated genetic predictor of anti-TNF response is the -308 G > A single-nucleotide polymorphism in the TNF promoter region. The presence of the -308 TNF G/G genotype appears to be a marker of good response to anti-TNF treatment. Anti-citrullinated protein antibodies (ACPA) have been linked with erosive disease, and have been established as the single most reliable prognostic factor in clinical practice. To test the hypothesis that the ACPA status may affect the -308 G/G patients rate of response to TNF blockade, we prospectively investigated a group of 52 RA patients with the -308 G/G genotype who were ACPA (+) or ACPA (-). All patients were treated with adalimumab, and the clinical response was studied using the Disease Activity Score in 28 joints (DAS28) at 24 weeks of treatment. Over 85% of patients were DAS28 responders in both groups. No significant differences were found between patients from both groups, according to the DAS28 criteria of response at week 24 (p = 0.79). In conclusion, our findings suggest that the ACPA status does not affect the clinical response to anti-TNF therapy in -308 TNF G/G patients.

Decrease in immunoglobulin free light chains in patients with rheumatoid arthritis upon rituximab (anti-CD20) treatment correlates with decrease in disease activity

OBJECTIVES

Immunoglobulin (Ig) free light chains (FLCs) are short-lived B cell products that contribute to inflammation in several experimental disease models. In this study, FLC concentrations in inflamed joints of patients with rheumatoid arthritis (RA) as compared to patients with osteoarthritis were investigated. In addition, the relationship of FLCs and disease activity upon B cell depletion (rituximab) in patients with RA was studied.

METHODS

Synovial fluid (SF) and tissue from patients with RA were analysed for local presence of FLCs using ELISA and immunohistochemistry. In addition, FLC concentrations were measured (at baseline, 3 and 6 months after treatment) in 50 patients with RA with active disease who were treated with rituximab. Changes in FLCs were correlated to changes in disease activity and compared to alterations in IgM, IgG, IgA, IgM-rheumatoid factor (RF) and IgG-anti-citrullinated protein antibody (ACPA) concentrations.

RESULTS

FLCs were detected in synovial tissue from patients with RA, and high FLC concentrations were found in SF from inflamed joints, which positively correlate with serum FLC concentrations. Serum FLC concentrations significantly correlated with disease activity score using 28 joint counts, erythrocyte sedimentation rate (ESR) and C reactive protein, and changes in FLC correlated with clinical improvement after rituximab treatment. Moreover, effect of treatment on FLC concentrations discriminated clinical responders from non-responders, whereas IgM-RF and IgG-ACPA significantly decreased in both patient groups.

CONCLUSIONS

FLCs are abundantly present in inflamed joints and FLC levels correlate with disease activity. The correlation of FLC concentrations and disease activity indicates that FLCs may be relevant biomarkers for treatment response to rituximab in patients with RA and suggests that targeting FLC may be of importance in the therapy of RA.

Association of serum markers with improvement in clinical response measures after treatment with golimumab in patients with active rheumatoid arthritis despite receiving methotrexate: results from the GO-FORWARD study

Introduction

The goal of this study was to identify serum markers that are modulated by treatment with golimumab with or without methotrexate (MTX) and are associated with clinical response.

Methods

Sera were collected at weeks 0 and 4 from a total of 336 patients (training dataset, n = 100; test dataset, n = 236) from the GO-FORWARD study of patients with active rheumatoid arthritis despite MTX. Patients were randomly assigned to receive placebo plus MTX; golimumab, 100 mg plus placebo; golimumab, 50 mg plus MTX; or golimumab, 100 mg plus MTX. Subcutaneous injections were administered every 4 weeks. Samples were tested for select inflammatory, bone, and cartilage markers and for protein profiling using multianalyte profiles.

Results

Treatment with golimumab with or without MTX resulted in significant decreases in a variety of serum proteins at week 4 as compared with placebo plus MTX. The American College of Rheumatology (ACR) 20, ACR 50, and Disease Activity Score (DAS) 28 responders showed a distinct biomarker profile compared with nonresponding patients.

Conclusions

ACR 20 and ACR 50 responders among the golimumab/golimumab + MTX-treated patients had a distinct change from baseline to week 4 in serum protein profile as compared with nonresponders. Some of these changed markers were also associated with multiple clinical response measures and improvement in outcome measures in golimumab/golimumab + MTX-treated patients. Although the positive and negative predictive values of the panel of markers were modest, they were stronger than C-reactive protein alone in predicting clinical response to golimumab.

Trial registration

http://ClinicalTrials.gov identification number: NCT00264550.

The continuous measurement of anti-CCP-antibodies does not help to evaluate the disease activity in anti-CCP-antibody-positive patients with rheumatoid arthritis

Anti-cyclic citrullinated peptide antibody (CCP-AB) are used for diagnosis of rheumatoid arthritis (RA). It is still unknown if the extent of CCP-AB levels is useful to assess the disease activity or the individual follow-up as an individual activity parameter. We investigated 40 patients with a known RA who were positive for CCP-AB. Correlation between disease activity (DAS 28) and the amount of levels of CCP-AB in all patients over time as well as the individual follow-up were analysed. A weak correlation between CCP-AB and DAS 28 [r = 0.19; p = 0.001] was found. The individual correlation between CCP-AB titre and DAS 28 ranged between r = -1 and r = 1, so a strong positive and also a strong negative correlation was seen in single patients. In patients with erosive RA the correlation was significantly more positive than in patients with non-erosive RA. Because the correlation between CCP-AB levels and parameters of disease activity measured by DAS 28 is very low, we conclude for monitoring the disease activity to use simply and established parameters like morning stiffness, HAQ or ESR. The individual follow-up of the levels of CCP-AB is by the moment not useful for monitoring the disease activity.