Production and characterization of an Fv-clasp of rheumatoid factor, a low-affinity human autoantibody

Rheumatoid factor (RF) is an autoantibody against IgG that affects autoimmune diseases and inhibits the effectiveness of pharmaceuticals and diagnostic agents. Although RFs derived from various germline genes have been identified, little is known about their molecular recognition mechanisms. In this study, the Fv-clasp format was used to prepare YES8c, an RF. We developed an Escherichia coli secretion expression system capable of producing milligram-scale of YES8c Fv-clasp per 1 L of culture. Although YES8c is an autoantibody with very low affinity, the produced Fv-clasp maintained specific binding to IgG. Interestingly, the molecules prepared by E. coli secretion had a higher affinity than those prepared by refolding. In the structure of the YES8c-Fc complex, the N-terminus of the light chain is close to Fc; therefore, it is suggested that the addition of the N-terminal methionine may cause collisions with Fc, resulting in reduced affinity. Our findings suggest that the Fv-clasp, which provides sufficient stability and a high bacterial yield, is a useful format for studying RFs with very low affinity. Furthermore, the Fv-clasp produced from a secretion expression system, which can properly process the N-terminus, would be suitable for analysis of RFs in which the N-terminus may be involved in interactions.

Novel and unique rheumatoid factors cross-react with viral epitopes in COVID-19

Rheumatoid factors (RFs), polyreactive antibodies canonically known to bind two conformational epitopes of IgG Fc, are a hallmark of rheumatoid arthritis but also can arise in other inflammatory conditions and infections. Also, infections may contribute to the development of rheumatoid arthritis and other autoimmune diseases. Recently, RFs only in rheumatoid arthritis were found to bind novel linear IgG epitopes as well as thousands of other rheumatoid arthritis autoantigens. Specific epitopes recognized by infection-induced polyreactive RFs remain undefined but could provide insights into loss of immune tolerance. Here, we identified novel linear IgG epitopes bound by RFs in COVID-19 but not rheumatoid arthritis or other conditions. The main COVID-19 RF was polyreactive, binding two IgG and multiple viral peptides with a tripeptide motif, as well as IgG Fc and SARS-CoV-2 spike proteins. In contrast, a rheumatoid arthritis-specific RF recognized IgG Fc, but not tripeptide motif-containing peptides or spike. Thus, RFs have disease-specific IgG reactivity and distinct polyreactivities that reflect the broader immune response. Moreover, the polyreactivity of a virus-induced RF appears to be attributable to a very short peptide motif. These findings refine our understanding of RFs and provide new insights into how viral infections may contribute to autoimmunity.

Ultrasonographic characteristics of major salivary glands in anti-centromere antibody-positive primary Sjögren's syndrome

Purpose

To investigate salivary gland ultrasonography (SGUS) findings in primary Sjögren’s syndrome (pSS) patients positive for the anti-centromere antibody (ACA) and compare these with those in ACA-negative pSS patients.

Methods

We analyzed demographic, clinical, laboratory, and SGUS data of pSS patients who fulfilled the 2002 American-European Consensus Group classification criteria for pSS. SGUS findings of four major salivary glands (bilateral parotid and submandibular glands) were scored in five categories and compared between ACA-positive and ACA-negative pSS patients. Linear regression analysis was performed to elucidate the factors associated with SGUS score.

Results

In total, 121 pSS patients were enrolled (19, ACA-positive). The ACA-positive patients were older (67.0 vs 58.0 years, P = 0.028), whereas anti-Ro/SSA and anti-La/SSB positivity was more prevalent in the ACA-negative group (89.2% vs 21.1%, P < 0.001, and 47.1% vs 10.5%, P = 0.007, respectively). The total SGUS and hypoechoic area scores were lower in ACA-positive patients (16.0 vs 23.0, P = 0.027, and 4.0 vs 7.0, P = 0.004, respectively). In univariate regression analysis, being positive for unstimulated salivary flow rate (USFR < 1.5 ml/15 min), anti-Ro/SSA, and rheumatoid factor were positively associated whereas ACA positivity was negatively associated with the SGUS score. In multivariate regression analysis, being positive for USFR, anti-Ro/SSA, and rheumatoid factor showed significant association with the SGUS score.

Conclusions

ACA-positive pSS patients showed a lower SGUS score than ACA-negative patients, which was especially prominent in the hypoechoic area component.

Effect of celecoxib combined with glucosamine hydrochloride in promoting the functional recovery and decreasing the inflammatory factor levels in patients with knee osteoarthritis

To explore the role of celecoxib with glucosamine hydrochloride on functional recovery and reduction of inflammatory factors in patients with knee osteoarthritis. Altogether 128 patients with knee osteoarthritis in the middle and early stage admitted to our hospital from January 2018 to July 2019 were selected and grouped into the control group (CG) (celecoxib tablet therapy) and the combination group (ComG) (celecoxib combined with glucosamine hydrochloride therapy). Blood routine indexes and inflammatory factor levels before and after intervention, Lequesne score, VAS pain and adverse reactions of the two groups of patients before and after intervention were explored. Before intervention, there was no evident difference between the two groups in each index (P>0.05). After intervention, the blood routine index IgM rheumatoid factor, albumin/globulin, erythrocyte sedimentation rate and inflammatory factors TNF-α, IL-6, IL-1β, hs-CRP levels in the ComG were evidently better than those in the CG, while Lequesne score and VAS pain score were lower than those in the CG (P<0.01). The total incidence of adverse reactions in the ComG was evidently lower than that in the CG. Celecoxib combined with glucosamine hydrochloride is effective in the treatment of knee osteoarthritis and has little adverse reactions.

The Prevalence of Sjögren's Syndrome in Rheumatoid Arthritis Patients and Their Clinical Features

BACKGROUND

To estimate the prevalence of Sjögren's syndrome (SS) in patients with rheumatoid arthritis (RA) and to compare the clinical features of RA patients with and without SS.

METHODS

We conducted a retrospective study of RA patients who visited a rheumatology clinic in a tertiary referral hospital in Korea between May 20 and July 22, 2016. All patients fulfilled the classification criteria for RA, and the diagnosis of SS was made clinically by rheumatologists and according to the 2002 American-European Consensus Group (AECG), 2012 American College of Rheumatology (ACR), and 2016 ACR/European League Against Rheumatism (EULAR) classification criteria. The prevalence was estimated as the number of SS patients within the total number of RA patients. The disease activity and treatment pattern of RA were compared between patients with and without SS.

RESULTS

Among 827 RA patients, 72 patients (8.7%) were diagnosed with SS by a rheumatologist, though only 60 patients (7.3%) satisfied the 2002 AECG classification criteria for SS. Fifty-two patients (6.3%) and 56 patients (6.8%) fulfilled the 2012 ACR and 2016 ACR/EULAR classification criteria, respectively. The prevalence of SS in RA patients was 10.5%, 17.0%, and 67.6% in rheumatoid factor, antinuclear antibody (≥ 1:80), and anti-Ro antibody positive patients, respectively.

CONCLUSION

The prevalence of SS among RA patients was 8.7% according to rheumatologists' diagnosis. The presence of SS did not affect the treatment patterns of RA patients. However, the autoantibody profiles and demographics of RA patients with SS differed from those of patients without SS.

The Impact of Cigarette Smoking on Risk of Rheumatoid Arthritis: A Narrative Review

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation and subsequent proliferation of synovial tissues, which eventually leads to cartilage and bone destruction without effective treatments. Anti-citrullinated cyclic peptide/protein antibody (ACPA) and rheumatoid factor (RF) are two main characteristic autoantibodies found in RA patients and are associated with unfavorable disease outcomes. Although etiologies and causes of the disease have not been fully clarified yet, it is likely that interactive contributions of genetic and environmental factors play a main role in RA pathology. Previous works have demonstrated several genetic and environmental factors as risks of RA development and/or autoantibody productions. Among these, cigarette smoking and HLA-DRB1 are the well-established environmental and genetic risks, respectively. In this narrative review, we provide a recent update on genetic contributions to RA and the environmental risks of RA with a special focus on cigarette smoking and its impacts on RA pathology. We also describe gene–environmental interaction in RA pathogenesis with an emphasis on cigarette smoking and HLA-DRB1.

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

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

Beyond the antibodies: serum metabolomic profiling of myasthenia gravis

INTRODUCTION

Myasthenia gravis (MG) is a chronic, potentially debilitating autoimmune disease characterized by weakness and rapid fatigue of the voluntary muscles that worsens on exertion. Left untreated, MG symptoms may cause significant morbidity or even death. To date, no robust biological marker is available to follow the course of the disease. Therefore, new diagnostic approaches and biological markers are essential not only for improved diagnosis of the disease but for improved outcomes.

OBJECTIVES

The present study applied a two-control, multi-label metabolomics profiling approach as a potential strategy for the identification of biomarkers unique to myasthenia gravis (MG).

METHODS

Metabolic analyses using acid- and dansyl-labelled serum from seropositive MG (n = 46), rheumatoid arthritis (RA) (n = 23) and healthy controls (HC) (n = 49) were performed on samples from adult patients presenting to the University of Alberta Hospital neuromuscular and rheumatology clinics. Comparisons between patients with MG vs. HC, and RA vs. HC were made using univariate and multivariate statistics.

RESULTS

Serum biomarker patterns were statistically significantly different between groups. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) models exhibited considerable distinction between all groups. Metabolites were then filtered to remove peak pairs common to both disease cohorts. Combined metabolite panels revealed clear separation between MG and HC for both library-matched (AUROC: 0.92 ± 0.03) and highest AUC patients (AUROC: 0.94 ± 0.05).

CONCLUSION

In patients presenting to the clinic with seropositive MG, metabolomic profiling is capable of distinguishing patients with disease from those without. These results provide an important first step towards a potential biomarker for improving MG identification.

Dose-response associations between metabolic indexes and the risk of comorbid type 2 diabetes mellitus among rheumatoid arthritis patients from Northern China: a case-control study

OBJECTIVE

To investigate whether there were any differences in the patterns of metabolic abnormalities between patients with rheumatoid arthritis (RA) with comorbid type 2 diabetes mellitus (T2DM) and other populations, and to plot the dose-response relationships between metabolic indexes and the risk of comorbid T2DM among patients with RA.

DESIGN AND SETTING

This is a retrospective case-control study using electronic medical records (EMRs). Patients with RA and/or T2DM or controls who were admitted to the First Affiliated Hospital of China Medical University between April 2008 and December 2016 were retrospectively recruited through the EMR system. After age-matching and sex-matching, 261 controls, 274 patients with T2DM, 276 patients with RA and 151 patients with RA+T2DM were eventually recruited.

RESULTS

Patients with RA+T2DM exhibited higher levels of systolic blood pressure (SBP), fasting plasma glucose (FPG) and triglyceride (TG) than the RA only patients. Moreover, the proportions of impaired fasting glucose (IFG), and total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) dyslipidaemia in the RA+T2DM group were higher than those in the RA alone group (for IFG: 28.48% vs 18.84%, p=0.02; for TC: 25.17% vs 15.22%, p=0.01; for LDL-C: 25.83% vs 17.03%; p=0.03). Rheumatoid factor (RF) positivity and IFG were independent risk indicators for comorbid T2DM among patients with RA (for RF positivity: OR=0.45; 95% CI: 0.29 to 0.69; p<0.001; for IFG: OR=1.70; 95% CI: 1.04 to 2.76; p=0.03).

CONCLUSION

Linear dose-response associations between SBP, TC, TG and the risk of comorbid T2DM among patients with RA were observed, whereas a non-linear dose-response association between FPG and the risk of comorbid T2DM was found. Patients with RA+T2DM were more likely to exhibit metabolic abnormalities than RA only patients. Patients with RA+T2DM with metabolic abnormalities deserve more attention from rheumatologists and endocrinologists.

Immunoglobulin G structure and rheumatoid factor epitopes

Antibodies are important for immunity and exist in several classes (IgM, IgD, IgA, IgG, IgE). They are composed of symmetric dimeric molecules with two antigen binding regions (Fab) and a constant part (Fc), usually depicted as Y-shaped molecules. Rheumatoid factors found in patients with rheumatoid arthritis are autoantibodies binding to IgG and paradoxically appear to circulate in blood alongside with their antigen (IgG) without reacting with it. Here, it is shown that rheumatoid factors do not react with native IgG in solution, and that their epitopes only become accessible upon certain physico-chemical treatments (e.g. heat treatment at 57 °C), by physical adsorption on a hydrophobic surface or by antigen binding. Moreover, chemical cross-linking in combination with mass spectrometry showed that the native state of IgG is a compact (closed) form and that the Fab parts of IgG shield the Fc region and thereby control access of rheumatoid factors and presumably also some effector functions. It can be inferred that antibody binding to pathogen surfaces induces a conformational change, which exposes the Fc part with its effector sites and rheumatoid factor epitopes. This has strong implications for understanding antibody structure and physiology and necessitates a conceptual reformulation of IgG models.

Serological profile of asymptomatic HCV positive patients with low level of cryoglobulins

Clinical spectrum of hepatitis C virus (HCV)-related cryoglobulinemia varies from an asymptomatic presentation to severe vasculitis and lymphoma. A recent study in HCV-negative patients suggests that low cryoglobulins (CGs) levels are responsible for severe renal and neurological complications. The aim of this study was to identify a panel of serological biomarkers associated with low levels of CGs in HCV-positive patients. We studied a population of 79 untreated patients with chronic HCV infection: 13 naïve patients without CGs; 28 patients with asymptomatic mixed cryoglobulinemia (MC) and low levels of CGs (16/28 with polyclonal type III and 12/28 with microheterogeneous type III CGs); 38 patients with symptomatic MC and high levels of type II CGs. Serum samples were collected and examined for rheumatoid factor (RF) IgG and IgM, free light chains (FLCs) and C3 and C4 complement components. We found that RF-IgG and IgM, free k chains and k+λ were increased while C4 component was reduced, both in symptomatic and asymptomatic patients. Our results suggest that, even in absence of MC symptoms, the low levels of CGs may represent a trigger of activation for immune system in course of HCV infection. The identification of a correlated biomarkers panel could improve the clinical management of these patients and pave the way for target treatment strategies. © 2018 BioFactors, 45(3):318-325, 2019.

Falsely elevated thyroglobulin and calcitonin due to rheumatoid factor in non-relapsing thyroid carcinoma: A case report

RATIONALE

Thyroglobulin (Tg) is an accurate indicator of clinical outcome after total thyroidectomy in patients with differentiated thyroid carcinoma. Usually, Tg levels agree with whole body scan. However, in some patient, discordant results were found, often because of Tg immunoassay interference. Several reports indicated that 2-site immunoassay interference with heterophile antibodies (HAb) can lead to misinterpretation of the laboratory test result.

PATIENT CONCERNS

We report a case of a 46-year-old woman referred to our endocrine clinic for markedly increased calcitonin (CT) without the associated clinical picture. The measurement was repeated with the same patient sample on a different analytical platform and the result was an undetectable CT level. The measurement of Tg was repeated on 3 different analytical platforms using chemiluminescence and electrochemiluminescence immunoassays and the results were different on each platform. HAb blocking tubes resulted in a different level of both CT and Tg, suggesting the presence of a heterophile substance in the serum sample. Further characterization showed reactivity to several animal species antibodies and an elevated level of the rheumatoid factor (RF).

DIAGNOSES

She was diagnosed as papillary thyroid carcinoma.

INTERVENTIONS

She had undergone thyroidectomy with lymph node dissection and radioactive therapy.

OUTCOMES

She was found not to have recurrence despite a high serum Tg level.

LESSONS

Our report illustrates a rare case of falsely elevated tumor markers levels due to assay interference caused by RF. This finding pointed out the importance of close communication between the clinician and laboratory staff in order to bring to light discordance between laboratory test results and clinical picture and avoid unnecessary diagnostic procedures and overtreatment.

Extracellular vesicles are associated with the systemic inflammation of patients with seropositive rheumatoid arthritis

Patients with rheumatoid arthritis (RA) and autoantibodies, such as rheumatoid factor and those against cyclic citrullinated peptides, are designated as seropositive and have a more severe disease with worse prognosis than seronegative RA patients. Understanding the factors that participate in systemic inflammation, in addition to articular commitment, would allow better treatment approaches for prevention of RA comorbidities and disease reactivation. We evaluated whether monocyte subsets and extracellular vesicles (EVs) could contribute to this phenomenon. Seropositive patients had higher levels of proinflammatory cytokines than those of seronegative patients and healthy controls (HCs); however, this systemic inflammatory profile was unrelated to disease activity. High frequencies of circulating EVs positive for IgG, IgM, CD41a, and citrulline, together with altered counts and receptor expression of intermediate monocytes, were associated with systemic inflammation in seropositive patients; these alterations were not observed in seronegative patients, which seem to be more similar to HCs. Additionally, the EVs from seropositive patients were able to activate mononuclear phagocytes in vitro, and induced proinflammatory cytokines that were comparable to the inflammatory response observed at the systemic level in seropositive RA patients; therefore, all of these factors may contribute to the greater disease severity that has been described in these patients.

Release of Antibodies and Cytokines from B Cells

Autoreactive B cells play a critical role in rheumatoid arthritis. These cells differentiate into long-living memory B cells and autoantibody-producing plasma cells and also present autoantigens to T cells to amplify misdirected immune responses. The therapeutic benefit of B-cell-deleting therapies suggests that B cells are emerging as important factors in the pathogenesis of RA. Aiming at evaluation of the function of B cells, which are usually derived from peripheral blood of RA patients and healthy donors, it is possible to conduct a series of experiments, such as in vitro assessment of antibody production and BCR-mediated cytokine release. These techniques can also be applied for in vivo application.

Synovial IL-21/TNF-producing CD4+ T cells induce joint destruction in rheumatoid arthritis by inducing matrix metalloproteinase production by fibroblast-like synoviocytes

Bone and cartilage destruction is one of the key manifestations of rheumatoid arthritis (RA). Although the role of T helper (Th)17 cells in these processes is clear, the role of IL-21-producing cells T cells has been neglected. We sought to investigate the role of IL-21 in RA by focusing on the functional characteristics of the main producers of this cytokine, synovial CD4+IL-21+ T cells. We show that the frequency of both synovial fluid (SF) CD4+IL-21+ or CD4+IL-21+TNF+ T cells in patients with RA was significantly higher compared with patients with psoriatic arthritis (PsA). The frequency of peripheral blood (PB) IL-21+CD4+ T cells in patients with RA positively correlated with disease activity score 28 (DAS28), serum anticyclic citrullinated peptide (anti-CCP) antibodies and IgM-rheumatoid factor (IgM-RF). IL-21 levels in RA SF were associated with matrix metalloproteinase (MMP)-1 and MMP-3. Related to this, IL-21 induced significantly the secretion of MMP-1 and MMP-3 in RA synovial biopsies. Sorted SF CD4+IL-21+ T cells significantly induced the release of MMP-1 and MMP-3 by fibroblast-like synoviocytes (FLS) compared with medium or CD4+IL-21- T cells in a coculture system. Neutralization of both IL-21 and TNF resulted in significantly less production of MMP by FLS. The results of this study indicate a new role for synovial CD4+IL-21+TNF+ T cells in promoting synovial inflammation/joint destruction in patients with RA. Importantly, IL-21 blockade in combination with anti-TNF might be an effective therapy in patients with RA by inhibiting MMP-induced inflammation/joint destruction.

Clinical Characteristics of Rheumatoid Arthritis Patients Achieving Functional Remission with Six Months of Biological DMARDs Treatment

Objective Although previous studies have reported the prognostic factors for functional remission, no reports have cited the predictive factors. Our aim was to study the predictive factors for functional remission, which is a treatment goal in rheumatoid arthritis (RA), after receiving biological disease-modifying antirheumatic drugs (bDMARDs) treatment for six months. Methods The study consisted of 333 RA patients treated with bDMARDs for six months. The following patient characteristics were investigated: age, gender, disease duration, type of bDMARDs, baseline steroid and methotrexate dosage, and levels of serum rheumatoid factor, matrix metalloprotease, anti-cyclic citrullinated peptides antibody, tumor necrosis factor-α, and interleukin-6. In our evaluation, we used the Simplified Disease Activity Index (SDAI) for RA disease activity, health assessment questionnaire disability index (HAQ-DI) for activity of daily living, Short Form (SF)-36 for quality of life, and Hamilton Depression Rating Scale (HAM-D) or Self-rating Depression Scale (SDS) to determine the patients' depression status. The subjects were divided into two groups: patients with HAQ-DI≤0.5 and HAQ-DI>0.5 at 6 months. Results A univariate analysis comparing a group of RA patients without functional remission (n=68) showed that the patients with functional remission (n=164) had the following in common compared with those without remission: younger age, shorter disease duration, lower baseline steroid dosage, lower SDAI, lower HAQ-DI, higher SF-36, and lower HAM-D. Only lower HAQ-DI scores and "mental health" score on the SF-36 were detected using a logistic regression analysis. Conclusion These findings suggested that RA patients with lower HAQ-DI and lower depression scores at baseline were more likely to achieve functional remission using bDMARDs treatment than those without these variables.

Increased Reactive Oxygen Species Formation and Oxidative Stress in Rheumatoid Arthritis

Background

Rheumatoid arthritis (RA) is an autoimmune inflammatory disorder. Highly reactive oxygen free radicals are believed to be involved in the pathogenesis of the disease. In this study, RA patients were sub-grouped depending upon the presence or absence of rheumatoid factor, disease activity score and disease duration. RA Patients (120) and healthy controls (53) were evaluated for the oxidant—antioxidant status by monitoring ROS production, biomarkers of lipid peroxidation, protein oxidation and DNA damage. The level of various enzymatic and non-enzymatic antioxidants was also monitored. Correlation analysis was also performed for analysing the association between ROS and various other parameters.

Methods

Intracellular ROS formation, lipid peroxidation (MDA level), protein oxidation (carbonyl level and thiol level) and DNA damage were detected in the blood of RA patients. Antioxidant status was evaluated by FRAP assay, DPPH reduction assay and enzymatic (SOD, catalase, GST, GR) and non-enzymatic (vitamin C and GSH) antioxidants.

Results

RA patients showed a higher ROS production, increased lipid peroxidation, protein oxidation and DNA damage. A significant decline in the ferric reducing ability, DPPH radical quenching ability and the levels of antioxidants has also been observed. Significant correlation has been found between ROS and various other parameters studied.

Conclusion

RA patients showed a marked increase in ROS formation, lipid peroxidation, protein oxidation, DNA damage and decrease in the activity of antioxidant defence system leading to oxidative stress which may contribute to tissue damage and hence to the chronicity of the disease.

The Elevated Secreted Immunoglobulin D Enhanced the Activation of Peripheral Blood Mononuclear Cells in Rheumatoid Arthritis

Immunoglobulin D (IgD) is a surface immunoglobulin that is expressed as either membrane IgD (mIgD) or secreted IgD (sIgD). Researchers have shown that sIgD is often elevated in patients with autoimmune diseases. The possible roles of sIgD on the function of peripheral blood mononuclear cells (PBMCs) in rheumatoid arthritis (RA) are still unclear. In this study, we compared the expression of sIgD, mIgD and IgD receptor (IgDR) in RA patients and healthy controls, and investigated the effect of sIgD on the function of PBMCs. We found that the levels of sIgD, mIgD and IgDR were significantly higher in RA patients compared with healthy controls. The concentrations of sIgD were positively correlated with soluble receptor activator of nuclear factor-κB ligand (sRANKL), rheumatoid factor (RF) and C-reactive protein (CRP) in RA patients. Strikingly, IgD could enhance the proliferation of PBMCs and induce IL-1α, IL-1β, TNF-α, IL-6 and IL-10 production from PBMCs. Moreover, the percentage of activated T cell subsets (CD4⁺CD69⁺, CD4⁺CD154⁺) and activated B cell subsets (CD19⁺CD23⁺, CD19⁺CD21⁺, CD19⁺IgD⁺ and CD19^-CD138⁺) were increased by IgD. The percentage of unactivated T cell subset (CD4⁺CD62L⁺) and immature B cell subset (CD19⁺IgM⁺IgD^-) were decreased by IgD in PBMCs. Furthermore, the expressions of IgDR on T and B cells were significantly increased by treatment with IgD. Our results demonstrate that IgD enhanced the activation of PBMCs, which may contribute to RA pathogenesis. Therefore, IgD could be a potential novel immunotherapeutic target for the management of RA.

Expression of Prostaglandin E2 Enzymes in the Synovium of Arthralgia Patients at Risk of Developing Rheumatoid Arthritis and in Early Arthritis Patients

Objective

Arthralgia may precede the development of synovial inflammation in autoantibody-positive individuals at risk of developing rheumatoid arthritis (RA). A major pathway involved in pain is the prostaglandin (PG) E₂ pathway. We investigated this pathway in the synovium of individuals with RA-specific autoantibodies and in early arthritis patients.

Methods

Nineteen autoantibody-positive individuals (IgM-rheumatoid factor and/or anti-cyclic citrullinated peptide antibodies) with arthralgia (n=15) and/or a positive family history of RA (n=8), who had been prospectively followed for at least 2 years, were included. In addition, we included early arthritis patients (disease-modifying antirheumatic drug naïve) who after 2 years follow up fulfilled classification criteria for RA (n=63), spondyloarthritis (SpA; n=14), or had unclassified arthritis (UA; n=27). In all subjects we assessed pain and performed synovial biopsy sampling by mini-arthroscopy at baseline. Tissue sections were examined by immunohistochemistry to detect and quantify PGE₂ pathway enzymes expression levels (mPGES-1; COX-1 and -2; 15-PGDH).

Results

In both study groups synovial expression of PGE₂ enzymes was not clearly related to pain sensation. Expression levels at baseline were not associated with the development of arthritis after follow up (6 out of 19 autoantibody-positive individuals). However, in early SpA patients the expression levels of mPGES-1 and COX-1 were significantly increased compared to RA and UA patients.

Conclusion

Pain in autoantibody-positive individuals without synovial inflammation who are at risk of developing RA and in early arthritis patients may be regulated by pathways other than the PGE₂ pathway or originate at sites other than the synovium. In contrast, in SpA, the PGE2 pathway may be inherently linked to the pathophysiology/etiology of the disease.

A predictive model for remission and low disease activity in patients with established rheumatoid arthritis receiving TNF blockers

The objective of this study was to identify predictors for remission or low disease activity (LDA) in established rheumatoid arthritis (RA) at 12 months of anti-TNF-α therapy. We have performed a prospective observational study in 90 consecutive patients with active RA receiving TNF-α inhibitors. Baseline and standard assessments were done every 3 months, including individual parameters (clinical and biological) and composite activity scores (28-joint disease activity score, DAS28). The primary outcome measure was DAS28-based EULAR response criteria. The multivariate logistic regression was used to analyze the association between disease activity and several RA baseline characteristics. Of the RA, 78.8 % was classified as good responders based on the EULAR-DAS28 criteria, 44.4 % RA achieving remission (DAS28 ≤ 2.6) and 34.4 %, LDA (DAS28 ≤ 3.2). Parameters associated with an increased likelihood of remission and LDA were initial DAS28-erythrocyte sedimentation rate ≤ 7 (odds ratio (OR) 3.3, 95 % confidence interval (CI) 2.03-5.81; OR 1.8, 95 % CI 1.09-6.68), Health Assessment Questionnaire Disability Index ≤  2 (OR 7.0, 95 % CI 1.56-31.91; OR 1.3, 95 % CI 1.03-5.79), C-reactive protein level ≤ 20 mg/l (OR 1.5, 95 % CI 0.29-8.22; OR 0.5, 95 % CI0.08-2.97), rheumatoid factor ≤ 20 IU/ml (OR 18.9, 95 % CI 10.79-38.36; OR 32.9, 95 % CI 4.03-269), anti-cyclic citrullinated peptide antibodies ≤ 40 IU/ml (OR 3.5, 95 % CI 0.67-18.19; OR 1.2, 95 % CI 1.02-1.59), concurrent prednisolone (OR 0.2, 95 % CI 0.05-0.36; OR 0.2, 95 % CI 0.06-0.63), methotrexate or leflunomide (OR 1.6, 95 % CI 1.2-13.53; OR 2.9, 95 % CI 1.20-4.36). A predictive matrix for remission and LDA in established active RA patients receiving TNF-α inhibitors was proposed. Further studies are necessary to confirm the value of such matrix in particular RA settings, leading to optimization of the use of anti-TNF-α therapy.

Dentofacial characteristics of patients with rheumatoid arthritis

OBJECTIVES

The aims of this study are to evaluate the dentofacial morphology of patients with rheumatoid arthritis (RA) and to compare the morphological data with those of healthy age- and sex-matched control subjects.

METHODS

Twenty-seven RA patients (mean age, 45.77 ± 8.64 years) and 25 healthy subjects (mean age, 44.80 ± 8.24 years) participated in this prospective study. Clinical and functional evaluations of the RA patients were assessed. The erythrocyte sedimentation rate, C-reactive protein level, rheumatoid factor level, and anti-citrullinated peptide antibodies (ACPA) titers of RA patients were determined, and DAS28 scores were calculated. Linear and angular measurements were performed on cephalometric tracings and condylar erosion was evaluated on lateral panoramic radiographs. Statistical comparison of the two groups was performed with an independent samples t test. Pearson correlation analysis was used to assess the relationship between the clinical and laboratory parameters.

RESULTS

Based on DAS28 scores, no patient with RA was in the remission period, 3 patients had low, 23 had medium, and 1 had high disease activity. Sixteen (59.26 %) patients with RA had positive ACPA titers. Lateral cephalometric radiographs revealed statistically significant difference between the two groups for the measurement of U1-NA (millimeter; p = 0.047), U1-NA (degrees; p = 0.031), L1-NB (degrees; p = 0.030), IMPA (L1-MP; p = 0.001), interincisal angle (U1-L1; degrees; p = 0.022) and midface length (Co-A; millimeter; p = 0.033). A significant positive linear correlation was found between disease duration time and DAS28 scores (r = 0.066, p = 0.040).

CONCLUSIONS

Dentoalveolar effects of RA on dentofacial morphology are more significant than the skeletal effects. Future studies with larger sample sizes are required to evaluate the exact effects of RA on dentofacial morphology.

CLINICAL RELEVANCE

Clinicians should consider the fact that RA-associated dentoalveolar changes can be observed and may affect the orthodontic treatment process.

Decreased recent thymus emigrant number in rheumatoid factor-negative polyarticular juvenile idiopathic arthritis

OBJECTIVES

To determine TCR excision circle (TREC) levels, a marker of recent thymic emigrants, in the peripheral lymphocyte pool of rheumatoid factor-negative (RFØ) polyarticular juvenile idiopathic arthritis (JIA) children.

METHODS

We studied TREC levels in peripheral blood mononuclear cells (PBMC) in 30 RFØ polyarticular JIA children with active disease and in 30 age- and gender-matched healthy controls. Signal-joint TREC concentration was determined by real-time quantitative-PCR as the number of TREC copies/microg PBMC DNA gauged by a standard curve with known number of TREC-containing plasmids.

RESULTS

TREC levels in PBMC were significantly lower in JIA (4.90 +/- 3.86 x 104 TRECs/microg DNA) as compared to controls (10.45 +/- 8.45 x 104 TRECs/microg DNA, p=0.001). There was an inverse correlation between age and TREC levels in healthy children (r=-0.438, p=0.016) but not in JIA. No clinical association was observed between TREC levels and disease activity and use of oral steroids and methotrexate.

CONCLUSIONS

The finding of decreased PBMC TREC levels in RFØ polyarticular JIA children is consistent with a low proportion of recent thymus emigrants. This may interfere with the equilibrium between populations of polyclonal and naïve T cells versus oligoclonal memory auto-reactive T cells and, therefore, may hinder the maintenance of immune tolerance in this disease.

[Observation on therapeutic effect of muscular needling combined with scarring moxibustion on active stage of rheumatoid arthritis]

OBJECTIVE

To observe the therapeutic effect of muscular needling combined with scarring moxibustion on active stage of rheumatoid arthritis (RA).

METHODS

Sixty cases of RA were randomly divided into a muscular needling group and a medication group, 30 cases in each group. The muscular needling group was treated by muscular needling on Quchi (LI 11), Sanyinjiao (SP 6), etc. combined with scarring moxibustion on Dazhui (GV 14), Zusanli (ST 36) etc., while the medication group was treated by oral administration of Diclofenac sodium and intramuscular injection of Methotrexate. The therapeutic effects, main symptoms and signs, erythrocyte sedimentation rate (ESR) and rheumatoid factor were observed in two groups before and after treatment.

RESULTS

The total effective rate of muscular needling group was 76.7%, and that of medication group was 73.3%, there was no significant difference between two groups (P > 0.05). The clinical symptoms, signs, and E8R of two groups were improved obviously compared with those before treatment (P < 0.01, P < 0.05), however there were no significant differences between the two groups after treatment (all P > 0.05). The adverse reactions of medication group were more eminent compared to the muscular needling group.

CONCLUSION

Muscular needling can obviously relieve the symptoms and signs of active stage rheumatoid arthritis and the effect is equivalent to oral administration of western medicine, the incidence of adverse reactions in the muscular needling group is obviously lower than that of western medication. Muscular needling is a safe and effective method for treatment of RA.

The effect of parental consanguinity on the clinical and laboratory findings of rheumatoid arthritis

AIMS

We aimed to evaluate the frequency of consanguinity among the parents of patients with rheumatoid arthritis (RA) and the influence of parental consanguinity on several clinical and laboratory parameters which reflect the severity of the disease.

METHODS AND PATIENTS

The study population consisted of 265 patients with RA which were divided into two groups with respect to the presence or absence of consanguinity between their parents. The frequency of parental consanguinity was compared with the general population. The two groups were compared with respect to family history of RA, the age of onset, the age at which RA was diagnosed, duration of the disease, the presence of rheumatoid nodules, vasculitis, serositis and the need for orthopaedic surgery, amyloidosis, the presence and level of rheumatoid factor and anti-cyclic citrullinated peptide antibodies, erosive changes on radiographs, and the need for anti-tumour necrosis factor therapy.

RESULTS

Twenty-one patients (8%) had parents who were consanguineous, which was not more frequent compared with the general population (14%). The mean age of disease onset and the mean age at which RA was diagnosed were lower in patients with parental consanguinity, although the difference was not statistically significant. The other clinical and laboratory parameters were also not different between the two groups.

CONCLUSION

The present data suggests that parental consanguinity has no effect on disease severity, and the frequency of consanguinity is not increased among the parents of patients with RA. A possible exception is the earlier disease onset and age at diagnosis which needs to be confirmed by larger studies.

[Gene expression profile of the peripheral CD4(+)T cells in patients with RF(+) and RF(-) rheumatoid arthritis]

AIM

To explore the differences of the gene expression of CD4(+) lymphocytes between the RF(+) and RF(-) patients with rheumatoid arthritis.

METHODS

mRNA of all the CD4(+) lymphocytes samples were extracted and identified. Then they were labeled and hybridized to microarrays.

RESULTS

Hierarchical clustering analysis showed there were 55 differential expression genes between the RF(+) and RF(-) patients with rheumatoid arthritis.

CONCLUSION

There are differential expression genes between the RF(+) and RF(-) patients and these genes are related to immunoresponse.

Protective effects of Pycnogenol on carbon tetrachloride-induced hepatotoxicity in Sprague-Dawley rats

Oxidative damage is implicated in the pathogenesis of various liver injuries. In the present study the ability of Pycnogenol (PYC) as an antioxidant to protect against CCl4-induced oxidative stress and hepatotoxicity in rats was investigated. Four experimental groups of six rats each were constructed: a vehicle control group received the respective vehicles (distilled water and corn oil) only; a CCl4 group received a 14-day repeated intraperitoneal (i.p.) dose of distilled water and then a single oral dose of CCl4 at 1.25 ml/kg; and the CCl4&PYC 10 and CCl4&PYC 20 groups received a 14-day repeated i.p. dose of PYC 10 and 20 mg/kg, respectively, and then a single oral dose of CCl4 at 1.25 ml/kg. Hepatotoxicity was assessed 24 h after the CCl4 treatment by measurement of serum aminotransferase (AST) and alanine aminotransferase (ALT) activities, hepatic malondialdehyde (MDA) and glutathione (GSH) concentrations, and catalase, superoxide dismutase (SOD), and glutathione-S-transferase (GST) activities. The results were confirmed histopathologically. The single oral dose of CCl4 produced significantly elevated levels of serum AST and ALT activities. Histopathological examinations showed extensive liver injuries, characterized by extensive hepatocellular degeneration/necrosis, fatty changes, inflammatory cell infiltration, congestion, and sinusoidal dilatation. In addition, an increased MDA concentration and decreased GSH, catalase, SOD, and GST were observed in the hepatic tissues. On the contrary, PYC treatment prior to the administration of CCl4 significantly prevented the CCl4-induced hepatotoxicity, including the elevation of serum AST and ALT activities and histopathological hepatic lesions, in a dose-dependent manner. Moreover, MDA and GSH levels and catalase, SOD, and GST activities in hepatic tissues were not affected by administration of CCl4, indicating that the pretreatment of PYC efficiently protects against CCl4-induced oxidative damage in rats. The results indicate that PYC has a protective effect against acute hepatotoxicity induced by the administration of CCl4 in rats, and that the hepatoprotective effects of PYC may be due to both the inhibition of lipid peroxidation and the increase of antioxidant activity.

Interaction between smoking, the shared epitope, and anti-cyclic citrullinated peptide: a mixed picture in three large North American rheumatoid arthritis cohorts

OBJECTIVE

Recently, Swedish members of the Epidemiological Investigation of Rheumatoid Arthritis (EIRA) provided evidence that smoking may trigger RA-specific immune reactions to citrullinated protein in carriers of HLA-DR shared epitope alleles. In an effort to confirm this interaction between smoking and shared epitope alleles, we performed a case-only analysis of 3 North American RA cohorts.

METHODS

A total of 2,476 white patients with RA were studied, 1,105 from the North American Rheumatoid Arthritis Consortium (NARAC) family collection, 753 from the National Inception Cohort of Rheumatoid Arthritis Patients (Inception Cohort), and 618 from the Study of New Onset Rheumatoid Arthritis (SONORA). All patients were HLA-DRB1 typed, and tested for anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor. Information about smoking history was obtained by questionnaire.

RESULTS

A significant association was found between smoking and the presence of anti-CCP in the NARAC and the Inception Cohort, but not in the SONORA. The shared epitope alleles consistently correlated with anti-CCP in all 3 populations. Using multiple logistic regression analyses, shared epitope alleles were still the most significant risk factor for anti-CCP positivity. Weak evidence of gene-environment interaction between smoking and shared epitope alleles for anti-CCP formation was found only in the NARAC.

CONCLUSION

Unlike the EIRA data, we could not confirm a major gene-environment interaction for anti-CCP formation between shared epitope alleles and smoking in 3 North American RA cohorts. Our data indicate a need for further studies to address the full range of environmental factors other than smoking that may be associated with citrullination and RA.

Expression of CD22 on peripheral B cells in patients with rheumatoid arthritis: relation to CD5-positive B cells

B cells in patients with rheumatoid arthritis (RA) are hyperactivated. Although B cell receptor signal transduction may be affected by various response regulators, CD22 plays an important role as a response regulator of B cells. Therefore, we investigated and examined CD22 expression on peripheral blood B cells of patients with RA. Thirty-two RA patients and 16 controls were enrolled in this study, and CD22 expressions on B cells were analyzed by flow cytometry. In patients with RA, CD22(+) B cells significantly decreased in comparison to the controls (ratio: P < 0.05). However, there was no correlation between this decrease and the clinical data. Interestingly, CD5(+) CD22(-) B cells significantly increased in RA patients. The decrease in CD22(+) B cells and increased in CD5(+)CD22(-) B cells play critical roles in the pathogenesis of RA mediated by the activation of B cells.

Distinctive gene expression signatures in rheumatoid arthritis synovial tissue fibroblast cells: correlates with disease activity

Gene expression profiling of rheumatoid arthritis (RA) and osteoarthritis (OA) joint tissue samples provides a unique insight into the gene signatures involved in disease development and progression. Fibroblast-like synovial (FLS) cells were obtained from RA, OA and control trauma joint tissues (non-RA, non-OA) and RNA was analyzed by Affymetrix microarray. Thirty-four genes specific to RA and OA FLS cells were identified (P<0.05). HOXD10, HOXD11, HOXD13, CCL8 and LIM homeobox 2 were highly and exclusively expressed in RA and CLU, sarcoglycan-gamma, GPR64, POU3F3, peroxisome proliferative activated receptor-gamma and tripartite motif-containing 2 were expressed only in OA. The data also revealed expression heterogeneity for patients with the same disease. To address disease heterogeneity in RA FLS cells, we examined the effects of clinical disease parameters (Health Assessment Questionnaire (HAQ) score, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), rheumatoid factor (RF)) and drug therapies (methotrexate/prednisone) on RA FLS cell gene expression. Eight specific and unique correlations were identified: human leukocyte antigen (HLA)-DQA2 with HAQ score; Clec12A with RF; MAB21L2, SIAT7E, HAPLN1 and BAIAP2L1 with CRP level; RGMB and OSAP with ESR. Signature RA FLS cell gene expression profiles may provide insights into disease pathogenesis and have utility in diagnosis, prognosis and drug responsiveness.

The autoantibody rheumatoid factor may be an independent risk factor for ischaemic heart disease in men

BACKGROUND

Subjects with rheumatoid arthritis have an increased prevalence of ischaemic heart disease (IHD). This is most likely in those people with the autoantibody rheumatoid factor (RF). RF is strongly associated with rheumatoid arthritis (RA) but is also present in up to 15% of all adults.

OBJECTIVE

To determine whether RF might identify people in a general population who also share an increased likelihood of developing IHD.

METHODS

Subjects from the Hertfordshire Cohort Study were investigated for the presence of RF. Subjects completed a questionnaire and attended a clinic where a history of IHD was recorded (ECG, coronary artery bypass grafting, Rose chest pain). Associations between the presence of RF, antinuclear antibodies (ANA), anticardiolipin antibodies (ACA) and IHD in 567 men and 589 women were investigated and compared with traditional risk factors for IHD.

RESULTS

RF was associated with an increased likelihood of IHD in men (odds ratio (OR) = 3.1, 95% CI 1.7 to 5.4, p<0.001). This increased risk could not be explained by traditional risk factors for IHD (mutually adjusted OR for RF 2.9 (95% CI 1.6 to 5.3), p<0.001). There was no significant association between RF in women or between ANA or ACA with IHD in men or women.

CONCLUSION

This work suggests that RF is an independent risk factor for IHD in the general population. It lends support to the importance of inflammation in atherosclerosis and suggests that autoimmune processes may be involved. In addition, it raises the intriguing possibility that RF may have a direct role in the pathogenesis of IHD in some subjects.

Crystal structure of a human autoimmune complex between IgM rheumatoid factor RF61 and IgG1 Fc reveals a novel epitope and evidence for affinity maturation

Rheumatoid factors (RF) are autoantibodies that recognize epitopes in the Fc region of immunoglobulin (Ig) G and that correlate with the clinical severity of rheumatoid arthritis (RA). Here we report the X-ray crystallographic structure, at 3 A resolution, of a complex between the Fc region of human IgG1 and the Fab fragment of a monoclonal IgM RF (RF61), derived from an RA patient and with a relatively high affinity for IgG Fc. In the complex, two Fab fragments bind to each Fc at epitopes close to the C terminus, and each epitope comprises residues from both Cgamma3 domains. A central role in the unusually hydrophilic epitope is played by the side-chain of Arg355, accounting for the subclass specificity of RF61, which recognizes IgG1,-2, and -3 in preference to IgG4, in which the corresponding residue is Gln355. Compared with a previously determined complex of a lower affinity RF (RF-AN) bound to IgG4 Fc, in which only residues at the very edge of the antibody combining site were involved in binding, the epitope bound by RF61 is centered in classic fashion on the axis of the V(H):V(L) beta-barrel. The complementarity determining region-H3 loop plays a key role, forming a pocket in which Arg355 is bound by two salt-bridges. The antibody contacts also involve two somatically mutated V(H) residues, reinforcing the suggestion of a process of antigen-driven maturation and selection for IgG Fc during the generation of this RF autoantibody.

Antibody-induced arthritis: disease mechanisms and genes involved at the effector phase of arthritis

During the development of rheumatoid arthritis (RA) autoantibodies to IgG-Fc, citrullinated proteins, collagen type II (CII), glucose 6 phosphoisomerase (G6PI) and some other self-antigens appear. Of these, a pathogenic effect of the anti-CII and anti-G6PI antibodies is well demonstrated using animal models. These new antibody mediated arthritis models have proven to be very useful for studies involved in understanding the molecular pathways of the induction of arthritis in joints. Both the complement and FcgammaR systems have been found to play essential roles. Neutrophils and macrophages are important inflammatory cells and the secretion of tumour necrosis factor-alpha and IL-1beta is pathogenic. The identification of the genetic polymorphisms predisposing to arthritis is important for understanding the complexity of arthritis. Disease mechanisms and gene regions studied using the two antibody-induced arthritis mouse models (collagen antibody-induced arthritis and serum transfer-induced arthritis) are compared and discussed for their relevance in RA pathogenesis.

Iron Ions and Haeme Modulate the Binding Properties of Complement Subcomponent C1q and of Immunoglobulins

The complement system and circulating antibodies play a major role in the defence against infection. They act at the sites of inflammation, where the harsh microenvironment and the oxidative stress lead to the release of free iron ions and haeme. The aim of this study was to analyse the consequences of the exposure of C1q and immunoglobulins to iron ions or haeme. The changes in target recognition by C1q and in the rheumatoid factor activity of the immunoglobulins were investigated. The exposure of C1q to ferrous ions increased its binding to IgG and to IgM. In contrast, haeme inhibited C1q binding to all studied targets, especially to IgG1 and C-reactive protein. Thus, the haeme released as a result of tissue damage and oxidative stress may act as a negative feedback regulator of an inappropriate complement triggering as seen in ischaemia-reperfusion tissue injury. The results also show that iron ions and haeme were able to reveal rheumatoid factor activity of IgG. The modulation of the C1q-target binding as well as the revealing of rheumatoid factor activity of IgG by exposure to redox-active agents released at the sites of inflammation may have important consequences for the understanding of the immunopathological mechanisms of inflammatory and autoimmune diseases.

Clinical practice format for choosing a second-line disease modifying anti-rheumatic drug in early rheumatoid arthritis after failure of 6months' first-line DMARD therapy

BACKGROUND

The objective was to develop a clinical practice format for choosing a second-line disease-modifying anti-rheumatic drug (DMARD) after a 6-month course of a first-line DMARD in patients with early RA.

METHODS

A panel of 34 experts selected treatment option from various scenarios using the Thurstone pairwise method. The experts had to choose between two proposed DMARDs without proposing other options. The scenarios were obtained using the three items: DAS28, rheumatoid factor status and radiographic structural damage. A sample of 240 among 480 scenarios for each expert was taken at random. Responses given by at least 20% of the experts were considered pertinent.

RESULTS

Recommendations for choosing a second DMARD for early RA after failure of a 6-month course of a first-line DMARD were established according to 4 parameters: type of first-line DMARD, activity, RF status and radiographic joint damage. The results of this study suggest that in patients with early RA who fail a 6-month course of first-line DMARD therapy, the best options may be addition of corticosteroid when disease activity is moderate to high and switching to a biologic agent when further radiographic joint damage occurs, particularly in patients with positive tests for RF.

CONCLUSION

Although our scenarios did not include step-up (add instead of substitute) strategies, except for corticosteroids, we feel that the format presented here can optimise the management of patients with early RA seen in clinical practice.

Differential expression of rheumatoid factor-associated cross-reactive idiotypes in Iranian seropositive and seronegative patients with rheumatoid arthritis

INTRODUCTION

High levels of rheumatoid factors (RF) are detectable in serum of the majority of patients with rheumatoid arthritis (RA), but 5-10% of patients remain seronegative (SN). Despite clinical and genetic similarities between these two subsets of RA, it has been proposed that they may be regarded as distinct clinical entities.

METHODS

In the present study a panel of monoclonal antibodies (mAb) recognizing RF-associated cross-reactive idiotypes (CRI) linked to the VH1 (G8), VH4 (LC1), VK3b (17-109) and a mAb recognizing the VK3 subgroup (C7) of immunoglobulin variable region (IgV) gene products were used to quantitate the level of expression of these gene products in serum and synovial fluid of 35 seropositive (SP) and 8 SN RA patients by capture ELISA.

RESULTS

While the concentration and relative proportion of the IgV are recognized by the mAb G8, 17-109 and C7 were significantly higher in serum and synovial fluid of the SP RA, compared to the SN-RA patients (G8, p = 0.009; 17-109, p = 0.0001; C7, p = 0.001). The CRI recognized by the mAb LC1 was highly represented in serum and synovial fluid of the SN-RA patients. There have been no significant differences in the level of expression of these IgV gene products (other than the product recognized by C7 mAb in SP patients) between serum and synovial fluid of either group of patients.

CONCLUSION

Our results suggest that the expressed repertoire of Ig VH and VK genes in these two subsets of RA is differentially regulated and may be influenced by selective mechanisms leading to positive or negative selection of certain genes.

The pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is due to a combination of phagocytosis and anaphylaxis gone awry. Immune complexes create their havoc via Fc gamma III receptors that signal via the tyrosine phosphorylation immunoreceptor pathway. Anaphylatoxins, mainly C5a, signal via the MEK kinase cascade, and both engage in cross-talk via NF kappa B. Aspirin-III blocks signals sent by both: immune complexes via FCR, and anaphylatoxin via C5 receptors. Drugs that affect both pathways, for example anti-B cell monoclonal antibodies, such as rituximab, and anti-C5 monoclonal antibodies, such as pexelizumab are currently being investigated. We now appreciate that cytokines are important mediators of inflammation in RA but are downstream of the primary insults: immune complexes and anaphylatoxins. We can therefore begin to ask what the antigen or antigens might be that produce IgGs reactive to 7 S or 19 S rheumatoid factors. The primary antigens of RA could well be CPs, formed perhaps by oral bacteria. Once immunoglobulins become recognized by rheumatoid factors, immune complexes form, and these activate anaphylatoxins. Phagocytosis and anaphylaxis are the proximal events of RA.

Bone marrow transplantation as a strategy for the treatment of autoimmune hearing loss in MRL/Mp-lpr/lpr mice

Sensorineural hearing loss (SNHL) has been reported to develop as a main part of or in combination with systemic and organ-specific autoimmune diseases. The aim of the current study is to treat autoimmune SNHL in MRL/Mp-lpr/lpr (MRL/lpr) mice, a murine model of systemic autoimmune disease, using allogeneic bone marrow transplantation (BMT), which replaces recipient bone marrow cells with bone marrow cells from a non-autoimmune-prone donor. The results indicate that BMT can be used to treat SNHL; cochlear pathology, serum autoantibodies and lupus nephritis are ameliorated. Therefore, it is conceivable that the autoimmune SNHL in the MRL/lpr mice results not from defects in the cochlea, including the stria vascularis, but from defects in the bone marrow, and BMT would therefore provide a curative effect on inner ear autoimmune dysfunction associated with systemic autoimmune diseases.

Rheumatoid Factors: Good or Bad for You?

BACKGROUND

Rheumatoid factors (RFs) are autoantibodies associated with rheumatoid arthritis. They can be detected in normal individuals, although transiently. This dichotomy has led to questions about the origins and types of RFs. Recently it has been shown that B cells that produce RFs only do so when activated by two signals, one from engagement of the B-cell receptor and the other from recognition of a pathogen-associated molecular pattern through a Toll-like receptor (TLR). These autoantibodies thus link the innate and acquired immune responses.

OBJECTIVE

Through a review of the literature, an examination of the current knowledge of RF induction is presented. The focus is on a discussion of a beneficial or detrimental role for RFs in normal individuals and in those with chronic disease.

RESULTS

What makes RF 'good' in some cases and 'bad' in others may reflect the type of RF produced. Low-affinity polyreactive IgM RFs are probably beneficial as they aid in the clearance of immune complexes that are more efficiently cleared, and the RF B cell can act as an antigen-presenting cell and stimulate host defense. However, large amounts of high-affinity RFs found in patients with chronic disease may be harmful by participation in a vicious cycle of autoantibody production by stimulation of self lymphocytes, and/or deposition in blood vessels thus causing vasculitis.

CONCLUSIONS

Whether RFs are beneficial or detrimental depends on the context in which they are expressed, the type and amount of RF produced, whether the response is perpetuated by TLR ligation and whether other cells are stimulated either directly or indirectly by RF-positive B cells.

Positive relationship between melatonin receptor type 1B polymorphism and rheumatoid factor in rheumatoid arthritis patients in the Korean population

Melatonin is reported to be an anti-inflammatory agent. No genetic study concerning the association between melatonin and inflammatory disease has yet been reported. Here we performed a polymorphism study on the melatonin receptor type 1B (MTNR1B) in Korean rheumatoid arthritis (RA) patients and controls. The polymorphism of MTNR1B located in 3'-untranslated region (rs 1562444) was selected for its higher rate of heterozygosity among other single nucleotide polymorphisms (SNPs) in both MTNR1A and MTNR1B genes and investigated in RA patients (n = 173) and healthy controls (n = 195) by polymerase chain reaction-restriction fragment length polymorphism assay using NlaIII restriction enzyme. No statistically significant difference in either genotype distribution or allele frequency was observed between RA patients and controls. The genotype distributions and allele frequencies of rheumatoid factor negative [RF(-)] patients were similar to those of controls. However, statistical analysis of genotype revealed a significant association (chi2 = 6.42, P = 0.04) is present between RF(+) and MTNR1B SNP (rs 1562444). Although no statistically significant difference in allele frequency between RF(+) and controls was observed (chi2 = 2.75, P = 0.10), the results might suggest that MTNR1B SNP (rs 1562444) is associated with the presence of RF in RA. This is the first study, to our knowledge, to report a positive genetic relationship between melatonin and RA.

Supplementation of fish oil and olive oil in patients with rheumatoid arthritis

OBJECTIVE

This study evaluated whether supplementation with olive oil could improve clinical and laboratory parameters of disease activity in patients who had rheumatoid arthritis and were using fish oil supplements.

METHODS

Forty-three patients (34 female, 9 male; mean age = 49 +/- 19y) were investigated in a parallel randomized design. Patients were assigned to one of three groups. In addition to their usual medication, the first group (G1) received placebo (soy oil), the second group (G2) received fish oil omega-3 fatty acids (3 g/d), and the third group (G3) received fish oil omega-3 fatty acids (3 g/d) and 9.6 mL of olive oil. Disease activity was measured by clinical and laboratory indicators at the beginning of the study and after 12 and 24 wk. Patients' satisfaction in activities of daily living was also measured.

RESULTS

There was a statistically significant improvement (P < 0.05) in G2 and G3 in relation to G1 with respect to joint pain intensity, right and left handgrip strength after 12 and 24 wk, duration of morning stiffness, onset of fatigue, Ritchie's articular index for pain joints after 24 wk, ability to bend down to pick up clothing from the floor, and getting in and out of a car after 24 wk. G3, but not G2, in relation to G1 showed additional improvements with respect to duration of morning stiffness after 12 wk, patient global assessment after 12 and 24 wk, ability to turn faucets on and off after 24 wk, and rheumatoid factor after 24 wk. In addition, G3 showed a significant improvement in patient global assessment in relation to G2 after 12 wk.

CONCLUSIONS

Ingestion of fish oil omega-3 fatty acids relieved several clinical parameters used in the present study. However, patients showed a more precocious and accentuated improvement when fish oil supplements were used in combination with olive oil.

The polymorphisms of Th1 cell surface gene Tim-3 are associated in a Korean population with rheumatoid arthritis

The family of T-cell immunoglobulin domain and mucin domain (TIM) proteins is identified to be expressed on T cells. A member of TIM family, TIM-3 is selectively expressed on the surface of differentiated Th1 cells. TIM-3 might have an important role in the induction of autoimmune diseases by regulating macrophage activation and interacts with TIM-3 ligand to regulate Th1 responses. In the present study, we analyzed the association of the genotype and allele frequencies between rheumatoid arthritis (RA) patients and the controls without RA using large samples size at the -1516G>T, -574T>G and 4259G>T polymorphic sites of human Tim-3 gene. We further investigated the relationships between the genotypes of each single nucleotide polymorphisms (SNPs) and C-reactive protein (CRP) or rheumatoid factor (RF) levels in RA patients. The genotype and allele frequencies of the -574T>G (P = 0.001 and 0.001, respectively) as well as the 4259G>T (P = 0.001 ands 0.003, respectively) between RA patients and non-RA controls were significantly different. These results strongly suggest that -574T>G and 4259G>T polymorphism of the Tim-3 might be associated with susceptibility to RA.

Dyslipoproteinemia in patients with active rheumatoid arthritis: effects of disease activity, sex, and menopausal status on lipid profiles

OBJECTIVE

To investigate the lipid profiles in patients with active rheumatoid arthritis (RA) and to assess the relationship of inflammatory disease activity markers, sex, and menopausal status with lipid profiles.

METHODS

Three groups of patients with active RA (n = 184) were studied: men (n = 61, mean age 50.8 +/- 4.81 yrs), premenopausal women (n = 58, mean age 39.2 +/- 2.44 yrs), and postmenopausal women (n = 65, mean age 60.4 +/- 2.14 yrs), and healthy controls (n = 161): men (n = 65, mean age 50.9 +/- 3.42 yrs), premenopausal women (n = 47, mean age 40.3 +/- 1.66 yrs), and postmenopausal women (n = 49, mean age 61.3 +/- 3.16 yrs). We measured fasting plasma levels of total cholesterol (TC), triglyceride (TG), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), lipoprotein (a) [LP(a)], apolipoprotein A1 (apo A1), apolipoprotein B (apo B), and erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).

RESULTS

Male RA patients had significantly higher apo B/apo A1 and LP(a) and lower HDL-C than male controls. Female RA patients had significantly higher TC, LDL-C, and LP(a) than female controls. Premenopausal RA patients had significantly higher LDL-C, TC/HDL-C, LDL-C/HDL-C, and apo B/apo A1 and lower TG and HDL-C than premenopausal controls. Postmenopausal RA women had significantly higher TG and LP(a) and lower TC than postmenopausal controls. Female RA patients had higher HDL-C, apo A1, and TC/HDL-C and lower apo B/apo A1 than male RA patients. Postmenopausal RA patients had significantly higher TC, TG, TC/HDL-C, apo B, LP(a), and LDL-C/HDL-C than premenopausal RA patients. CRP correlated positively with TC/HDL-C, LDL-C/HDL-C, and apo B/apo A1 and negatively with HDL-C in male RA patients. In female RA patients CRP had positive correlation with TC/HDL-C and LDL-C/HDL-C and negative correlation with HDL-C.

CONCLUSION

These findings suggest that patients with active RA have altered lipid profiles and that disease activity, sex, and menopausal status affect lipid profiles, and these would be expected to change the pattern of atherosclerotic events in RA.

Infective endocarditis: improving the diagnostic yield

INTRODUCTION

Isolating aetiological agents in patients with infective endocarditis (IE) remains problematical. We postulated that the high local incidence of culture-negative IE resulted from antibiotic exposure prior to blood cultures and that a structured delay in therapy in the subacute presentation would improve the diagnostic yield.

AIM

We aimed to prospectively observe the diagnostic approach and give an overview of supplementary laboratory tests.

STUDY DESIGN

Patients with suspected IE were enrolled into this analytical observational study and followed up for six months (n = 92). We compared the diagnostic yield and outcome in cases where antibiotics were withheld for 72 hours, with those cases who received early antimicrobials, despite being deemed safe for delayed therapy.

RESULTS

Definitive diagnoses (definite or excluded IE) were made in 92.8% of patients where antibiotics were delayed, compared to 60% of patients who received empirical treatment (p = 0.08). The mortality rates were 18.4% and 30.0% (p = 0.18). Twenty-three of 26 patients with definite culture-negative IE received antibiotics during the 48 hours preceding cultures, compared to eight of 21 culture-positive patients (P < 0.001). Screening for atypical bacteria did not improve the yield. C-reactive protein (CRP) had a sensitivity of 97.0% (negative predictive value 87.5%), whereas a positive rheumatoid factor (RF) had a specificity of 93.8% (positive predictive value 91.7%).

CONCLUSIONS

We observed tendencies towards a greater diagnostic yield and lower mortality where antibiotics were initially withheld. Antibiotic prior to blood cultures were an important cause of culture-negative IE. A normal CRP proved useful in excluding IE; a positive RF strongly favoured IE.

Antibodies against cyclic citrullinated peptide and IgA rheumatoid factor predict the development of rheumatoid arthritis

OBJECTIVE

To evaluate the prevalence and predictive value of anti-cyclic citrullinated peptide (anti-CCP) antibodies in individuals who subsequently developed rheumatoid arthritis (RA) and to determine the relationship to rheumatoid factor (RF) of any isotype.

METHODS

A case-control study was nested within the Northern Sweden Health and Disease Study and the Maternity cohorts of Northern Sweden. Patients with RA were identified among blood donors whose samples had been taken years before the onset of symptoms. Control subjects matched for age, sex, date of sampling, and residential area were selected randomly from the same cohorts. Anti-CCP antibody and RFs were determined using enzyme immunoassays.

RESULTS

Eighty-three individuals with RA were identified as having donated blood before presenting with any symptoms of joint disease (median 2.5 years [interquartile range 1.1-4.7] before RA). In samples obtained before the onset of RA, the prevalence of autoantibodies was 33.7% for anti-CCP, 16.9% for IgG-RF, 19.3% for IgM-RF, and 33.7% for IgA-RF (all highly significant compared with controls). The sensitivities for detecting these autoantibodies >1.5 years and </=1.5 years before the appearance of any RA symptoms were 25% and 52% for anti-CCP, 15% and 30% for IgM-RF, 12% and 27% for IgG-RF, and 29% and 39% for IgA-RF. In conditional logistic regression models, anti-CCP antibody and IgA-RF were found to be significant predictors of RA.

CONCLUSION

Anti-CCP antibody and RFs of all isotypes predated the onset of RA by several years. The presence of anti-CCP and IgA-RF predicted the development of RA, with anti-CCP antibody having the highest predictive value. This indicates that citrullination and the production of anti-CCP and RF autoantibodies are early processes in RA.

Rheumatoid factor-like IgM in Plasmodium berghei (Apicomplexa: Haemosporida) infections of BALB/c mice

Groups of female BALB/c mice infected by intravenous injection with 50 erythrocytes containing Plasmodium berghei Vincke et Lips, 1948 were sacrificed on days 3 through 12 after infection. Rheumatoid factor-like IgM (RF-IgM) and parasite-specific IgG levels were determined by enzyme-linked immunosorbent assay in serum specimens and in culture medium removed from spleen cell cultures established at sacrifice. All four mouse IgG subisotypes were recognized by RF-IgM molecules induced by Plasmodium berghei infection, and in this regard, the parasite-induced RF-IgM response resembled that induced by lipopolysaccharide polyclonal activation. Plasmodium berghei infection resulted in a biphasic RF-IgM response, with infected animals demonstrating significantly increased levels of RF-IgM early in the infection and significantly decreased levels late in the infection, compared to uninfected control mice. The decreased levels of RF-IgM observed late in infection correlated with increasing parasitaemia levels, and were primarily due to a decrease in RF-IgM specific for mouse IgG2a. Late infection levels of RF-IgM specific for IgGI, IgG2b, and IgG3 were not significantly different from those of control animals.

Classification of juvenile idiopathic arthritis: should family history be included in the criteria?

OBJECTIVE

(i) To determine the efficacy of the Durban classification for children with juvenile idiopathic arthritis (JIA) where < 5 joints were involved at onset (with systemic arthritis excluded) by determining the proportion of the cohort that proved to be "unclassifiable"; (ii) to define reasons for cases being "unclassifiable," particularly regarding family history; and (iii) to compare the efficacy of a proposed hierarchical system (an unofficial modification of the Durban classification) with the Durban classification, where family history details are included as descriptors, rather than as classification criteria.

METHODS

Charts were reviewed of 50 children with fewer than 5 joints involved at presentation for JIA, followed for at least 12 months, with systemic arthritis excluded. Cases were classified according to the EULAR criteria, the Durban criteria, and by a proposed "modified Durban" classification subject to hierarchy, with exclusions in the following order: systemic arthritis, rheumatoid factor (RF) positive arthritis, psoriasis or a combination of dactylitis and psoriatic nail changes (psoriatic arthritis), and HLA-B27 positive arthritis (enthesitis related arthritis), with the remainder of children being classified as having either RF negative polyarthritis or RF negative oligoarthritis, depending on number of joints involved, with additional information noted as descriptors. The "modified Durban" classification was proposed only to stimulate discussion among clinicians.

RESULTS

Of 50 children, 56% were "unclassifiable" by the Durban classification, mainly because of inadequate family history despite appropriate questioning. Using the proposed "modified Durban" classification, 2% were "unclassifiable." Family history was classified as inadequate for the following reasons: The parents did not know family history; the child or parent was adopted; the father was unknown or parent died early; parents never attended; extended family had lost communication with parents; or a relative was considered to have psoriasis, but not confirmed by dermatologists. Other reasons for "unclassifiable" included: dermatologists unable to confirm psoriasis; family history of inflammatory bowel disease and sacroiliitis but B27 status unknown; proband B27 negative but family history of B27-related disease; family history of psoriasis, but patient had insufficient criteria for psoriatic arthritis and therefore excluded from oligoarthritis, psoriatic arthritis and other groups.

CONCLUSION

(i) The Durban classification showed poor efficacy for JIA where < 5 joints were involved at onset, with more than half the cases being "unclassifiable". (ii) The most common reason was that appropriate family history was not available despite being sought by the clinician. (iii) A proposed hierarchical system, an unofficial modification of the Durban classification, showed good efficacy, with only one of 50 cases being "unclassifiable."