Anti-CCP antibodies measured at disease onset help identify seronegative rheumatoid arthritis and predict radiological and functional outcome

Factors associated with resolution of ultrasound subclinical synovitis in anti-CCP-positive individuals with musculoskeletal symptoms: a UK prospective cohort study

BACKGROUND

Subclinical synovitis occurs in a third of individuals at risk of rheumatoid arthritis. The objective of this study was to assess the reversibility of subclinical synovitis in individuals at risk of rheumatoid arthritis who are positive for anti-cyclic citrullinated peptide (CCP) antibody with musculoskeletal symptoms and investigate factors associated with its resolution within 12 months.

METHODS

We conducted a single-centre, prospective, cohort study in the UK, recruiting individuals aged 18 years or older who were anti-CCP-positive with a new non-specific musculoskeletal symptom but no clinical synovitis. Referrals were made through primary or secondary care. Participants attended a baseline visit, which included a clinical assessment, blood tests, patient questionnaires, and a musculoskeletal ultrasound scan (ie, of wrists and metacarpophalangeal, proximal interphalangeal, and metatarsophalangeal joints), and then follow-up visits every 3 months for the first year, with a repeat ultrasound scan every 12 months. Participants with subclinical synovitis (ie, grey scale ≥1 and power Doppler ≥1) in at least one joint at baseline were selected for this analysis. Investigation of good prognostic factors by 12 months was done first using univariable analysis to identify significant factors in participants with no missing data. Then receiver operating characteristic (ROC) curves were used to establish the optimal cutoffs for significant continuous variables. Finally, a modified Poisson regression approach was performed to identify the best prediction model and was adjusted for confounders, using data from all participants, with missing values imputed. This study is registered with ClinicalTrials.gov, NCT02012764.

FINDINGS

Between June 30, 2008, and Feb 24, 2020, 451 participants consented to participate in the CCP study and 122 (27%) individuals had subclinical synovitis at baseline, of whom 90 (74%) had data available at 12 months. Mean age was 54·1 years (SD 12·5), and 63 (70%) of 90 participants were women and 27 (30%) were men. Subclinical synovitis resolved in 43 (48%) of 90 participants, whereas subclinical synovitis persisted in 47 (52%) participants, 27 (57%) of whom developed clinical synovitis within 12 months. In the multivariable analysis, low anti-CCP titre (relative risk [RR] 1·52, 95% CI 1·04-2·22), negative rheumatoid factor (1·54, 0·92-2·58), subclinical synovitis in only one joint (1·62, 1·04-2·50), and an erythrocyte sedimentation rate of 15 mm/h or lower (1·82, 1·15-2·87) were predictors of subclinical synovitis resolution within 12 months (ie, good prognostic factors). ROC curve showed an area under the curve of 0·84 (95% CI 0·76-0·92; p<0·0001). Resolution occurred in seven (100%) of seven participants with all four factors present, and in only one (7%) of 14 participants with none of the factors present.

INTERPRETATION

In individuals who were anti-CCP-positive, subclinical synovitis disappeared in approximately half of the participants by 12 months and was associated with the presence of good prognostic factors. Subclinical synovitis should be interpreted in the context of these additional factors.

FUNDING

National Institute for Health Research Leeds Biomedical Research Centre.

Characterization and use of the ECV304 autoantigenic citrullinome to understand anti-citrullinated protein/peptide autoantibodies in rheumatoid arthritis

Background

Anti-citrullinated protein antibodies (ACPAs) are highly specific for rheumatoid arthritis (RA). In vivo, ACPAs target peptidyl-citrulline epitopes (cit-) in a variety of proteins (cit-prot-ACPAs) and derived peptides (cit-pept-ACPAs) generated via the peptidylarginine deiminase (PAD) isoenzymes. We aimed to identify a cell line with self-citrullination capacity, to describe its autoantigenic citrullinome, and to test it as a source of autocitrullinated proteins and peptides.

Methods

Human cell lines were screened for cit-proteins by Western blot. PAD isoenzymes were identified by RT-PCR. Autocitrullination of ECV304 was optimized, and the ECV304 autocitrullinomes immunoprecipitated by sera from three RA patients were characterized by mass spectrometry. Cit-pept-ACPAs were detected using anti-CCP2 ELISA and cit-prot-ACPAs, by an auto-cit-prot-ECV304 ELISA. Sera from 177 RA patients, 59 non-RA rheumatic disease patients and 25 non-disease controls were tested.

Results

Of the seven cell lines studied, only ECV304 simultaneously overexpressed PAD2 and PAD3 and its extracts reproducibly autocitrullinated self and non-self-proteins. Proteomic analysis of the cit-ECV304 products immunoprecipitated by RA sera, identified novel cit-targets: calreticulin, profilin 1, vinculin, new 14–3-3 protein family members, chaperones, and mitochondrial enzymes. The auto-cit-prot-ECV304 ELISA had a sensitivity of 50% and a specificity of 95% for RA diagnosis.

Conclusions

ECV304 cells overexpress two of the PAD isoenzymes capable of citrullinating self-proteins. These autocitrullinated cells constitute a basic and clinical research tool that enable the detection of cit-prot-ACPAs with high diagnostic specificity and allow the identification of the specific cit-proteins targeted by individual RA sera.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02698-2.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Anti-cyclic-citrullinated-protein-antibodies in psoriatic arthritis patients: how autoimmune dysregulation could affect clinical characteristics, retention rate of methotrexate monotherapy and first line biotechnological drug survival. A single center retrospective study

AIM

Occasional findings of anti-cyclic-citrullinated-protein-antibodies (anti-CCP) were rarely observed in psoriatic arthritis (PsA). The aim of our study is to evaluate whether the presence of anti-CCP can determine different clinical subsets and influence methotrexate monotherapy survival, and biotechnological drug retention rate.

METHODS

We conducted a retrospective study on PsA patients. All patients were required to fulfill the CASPAR criteria for PsA, and to present juxta-articular osteo-proliferative signs at X-ray. The exclusion criteria were age less than 18 years old, satisfaction of rheumatoid arthritis classification criteria, and seropositivity for rheumatoid factor. Clinical characteristics, anti-CCP titer, drug survival and comorbidities information were recorded for each patient. Statistical significance was set at p ⩽ 0.05.

RESULTS

Of 407 patients with PsA screened 113 were recruited. Twelve patients were anti-CCP positive. Methotrexate monotherapy survival was shorter in patients with anti-CCP (150 ± 48.3 weeks versus 535.3 ± 65.3 weeks; p = 0.026) [discontinuation risk hazard ratio (HR) = 2.389, 95% confidence interval (CI) 1.043, 5.473; p = 0.039] than those without. Significant shorter survival of first-line biotechnological drugs (b-DMARDs) was observed in the anti-CCP positive group than in that without (102.05 ± 24.4 weeks versus 271.6 ± 41.7 weeks; p = 0.005) with higher discontinuation risk (HR = 3.230, 95% CI 1.299, 8.028; p = 0.012). A significant higher rate of multi-failure (more than second-line b-DMARDs) was found in anti-CCP positive patients than in those without (50% versus 14%, p = 0.035).

CONCLUSION

Anti-CCP in PsA could be suggestive of more severe disease, with worse drug survival of both methotrexate monotherapy and first-line b-DMARDs, and higher chance to be b-DMARDs multi-failure. So, they can be considered for more intensive clinical management of these patients.

A new tool for early diagnosis of rheumatoid arthritis using combined biomarkers; synovial MAGE-1 mRNA and serum anti-CCP and RF

Introduction

rheumatoid arthritis (RA) is a common autoimmune disease with unknown etiology and pathogenesis. Biomarkers have the potential to aid in the clinical diagnosis of the disease, or to provide means of detecting early signs of the disease. Evaluating Melanoma associated antigen genes (MAGE-1) mRNA expression rate in synovial fluid cells and serum levels of anti-cyclic citrullinated peptides (anti-CCP) and rheumatoid factor (RF) for RA early diagnosis.

Methods

a total of 213 subjects were enrolled in the study, 135 RA patients and 78 normal subjects with traumatic knee joints (control group). Serum RF and anti-CCP were estimated quantitatively using ELISA. MAGE-1 mRNA expression rate was analyzed by RT-PCR.

Results

a significant increase in serum levels of RF IgM and anti-CCP in RA patients compared to the controls. A positively significant correlation was found between serum anti-CCP and RF IgM. The expression rate of MAGE-1 mRNA was 100% in RA patients versus the controls (0%). The specificity and the sensitivity of the three biomarkers was 100%.

Conclusion

the high expression rate of MAGE-1 in synovial fluid cells of RA patients is encouraging its utilization as a diagnostic biomarker for RA. The combined use of MAGE-1 transcript in synovial fluid cells, serum RF and anti-CCP is recommended for improving early diagnostic ability of RA.

Use of a Citrullinated Peptide Panel for Detection of Anti-Citrullinated Protein Antibodies by Enzyme-Linked Immunosorbent Assay

Anti-citrullinated protein antibodies (ACPA)s are a hallmark of rheumatoid arthritis (RA) and are essential for serological diagnosis of RA.ACPAs are not specific for a single citrullinated target; in fact, several citrullinated ACPA target proteins have been described. As a consequence, ACPAs are primarily detected by enzyme-linked immunosorbent assays, where several citrullinated peptides are used as target antigens.This chapter focuses on the detection of ACPAs using a recently developed peptide panel in enzyme-linked immunosorbent assays.

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

BACKGROUND

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

OBJECTIVE

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

DATA SOURCES

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

STUDY SELECTION

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

RESULTS

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

LIMITATIONS

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

SUGGESTED RESEARCH PRIORITIES

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

CONCLUSIONS

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

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016042402.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Economic Evaluation of Anticyclic Citrullinated Peptide Positivity in Rheumatoid Arthritis

BACKGROUND

Anticyclic citrullinated peptide (anti-CCP) positivity may be a strong predictor of joint erosion and a potential biomarker for guiding treatment decisions for rheumatoid arthritis (RA). However, limited studies are currently available on the effect of anti-CCP positivity on health care utilization and/or medical costs of RA patients.

OBJECTIVE

To investigate short-term and long-term direct health care expenditures associated with anti-CCP positivity in newly diagnosed RA patients.

METHODS

A retrospective cohort study was conducted in adult RA patients within a U.S. integrated health care delivery system (January 1, 2007-June 30, 2015). Patients were required to have 2 RA diagnoses and treatment with a conventional or biologic disease-modifying antirheumatic drug (DMARD) within 12 months. The first RA diagnosis date was labeled as the index date, and patients were followed until they left the health plan, died, or reached the end of the study period. Patient demographics, anti-CCP results, comorbid conditions, and health care resource utilization during baseline (12 months before the index date) and follow-up periods were collected. Nationally recognized direct medical costs were assigned to health care utilization to calculate health care costs in 2015 U.S. dollars. The baseline differences between anti-CCP positivity and negativity and differences in censoring during follow-up were addressed using propensity scores. The mean differences in costs were estimated using recycled prediction methods.

RESULTS

2,448 newly diagnosed RA patients were identified and followed for a median of 3.7 years (range = 1-8 years). At baseline, 65.8% of patients were anti-CCP positive. Anti-CCP-positive patients had fewer comorbid conditions at baseline. During the first 12 months of follow-up, median (interquartile range) total health care expenditures for anti-CCP-positive and anti-CCP-negative patients were $6,200 ($3,563-$13,260) and $7,022 ($3,885-$12,995), respectively. After adjusting for baseline differences, total incremental mean cost associated with anti-CCP positivity during the first 12 months was estimated to be $2,163 per patient (P = 0.001). The annual incremental costs in anti-CCP-positive patients became progressively larger over time, from $2,163 during the first year to $5,062 during the fourth year. Anti-CCP positivity was associated with higher prescription, laboratory testing, and rheumatologist utilization. A higher percentage of anti-CCP-positive patients received 1 or more biologic DMARDs (11.6% for anti-CCP-positive vs. 5.7% for anti-CCP negative; P < 0.001) compared with anti-CCP-negative patients during the 12-month follow-up, which resulted in $2,499 in incremental prescription costs (P < 0.001). Total additional burden associated with anti-CCP positivity during the first 4 years was estimated to be $14,089 per patient.

CONCLUSIONS

In newly diagnosed RA patients, higher economic burden associated with anti-CCP positivity was mainly driven by prescription costs.

DISCLOSURES

This research and manuscript were funded by Bristol-Myers Squibb (BMS). Alemao and Connolly are employees and shareholders of BMS and participated in the design of the study, interpretation of the data, review/revision of the manuscript, and approval of the final version of the manuscript. An and Cheetham received a grant from BMS for this research. At the time of this study, An was employed by Western University of Health Sciences, and Cheetham was employed by Kaiser Permanente Southern California. Bider-Canfield, Kang, and Lin have nothing to disclose. Some study results were presented as a poster at the American College of Rheumatology Annual Meeting; November 5, 2017; San Diego, CA, and at the International Society for Pharmacoeconomics and Outcomes Research Meeting; May 19, 2018; Baltimore, MD.

Burning controversies in NETs and autoimmunity: The mysteries of cell death and autoimmune disease

The causes and mechanisms of autoimmune disease pose continuing challenges to the scientific community. Recent clues implicate a peculiar feature of neutrophils, their ability to release nuclear chromatin in the form of neutrophil extracellular traps (NETs), in the induction or progression of autoimmune disease. Efforts to define the beneficial versus detrimental effects of NET release have, as yet, only partially revealed mechanisms that guide this process. Evidence suggests that the process of NET release is highly regulated, but the details of regulation remain controversial and obscure. Without a better understanding of the factors that initiate and control NET formation, the judicious modification of neutrophil behaviour for medically useful purposes appears remote. We highlight gaps and inconsistencies in published work, which make NETs and their role in health and disease a puzzle that deserves more focused attention.

Mechanistic immunological based classification of rheumatoid arthritis

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

Human MHC-II with Shared Epitope Motifs Are Optimal Epstein-Barr Virus Glycoprotein 42 Ligands-Relation to Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disorder of unknown etiology, which is characterized by inflammation in the synovium and joint damage. Although the pathogenesis of RA remains to be determined, a combination of environmental (e.g., viral infections) and genetic factors influence disease onset. Especially genetic factors play a vital role in the onset of disease, as the heritability of RA is 50–60%, with the human leukocyte antigen (HLA) alleles accounting for at least 30% of the overall genetic risk. Some HLA-DR alleles encode a conserved sequence of amino acids, referred to as the shared epitope (SE) structure. By analyzing the structure of a HLA-DR molecule in complex with Epstein-Barr virus (EBV), the SE motif is suggested to play a vital role in the interaction of MHC II with the viral glycoprotein (gp) 42, an essential entry factor for EBV. EBV has been repeatedly linked to RA by several lines of evidence and, based on several findings, we suggest that EBV is able to induce the onset of RA in predisposed SE-positive individuals, by promoting entry of B-cells through direct contact between SE and gp42 in the entry complex.

Tocilizumab treatment leads to improvement in disease activity regardless of CCP status in rheumatoid arthritis

OBJECTIVE

Autoantibodies can be useful in predicting response to certain treatments in rheumatoid arthritis (RA). We aimed to evaluate initial response to tocilizumab (TCZ) by change in physician and patient-reported outcomes and laboratory parameters in a real-world cohort of patients with RA. We analyzed the data by autoantibody status to determine whether patients with seronegative RA had improved response to tocilizumab when compared to their seropositive counterparts.

METHODS

Data from the CORRONA RA registry were analyzed. Patients were included if they were started on TCZ and had data from a follow-up visit 4-8 months after initiation, as well as having information on serologic status. Serologic status was determined by presence of anti-cyclic citrullinated peptide (CCP) antibodies. Changes in disease activity measures from baseline to follow-up visit were evaluated.

RESULTS

Both CCP-negative and -positive groups had statistically significant improvement in physician-reported measurements (physician rating of disease activity and joint counts), patient-reported measures (disease activity, pain, and fatigue), and acute phase reactants after 4-8 months of treatment with tocilizumab. The magnitude of improvement, however, did not differ significantly by CCP status.

CONCLUSION

Tocilizumab led to statistically significant improvement in all patient- and physician-reported measures of disease activity evaluated in this cohort of patient with RA. The response to tocilizumab did not differ by CCP status.

Patient-reported Outcomes as Predictors of Change in Disease Activity and Disability in Early Rheumatoid Arthritis: Results from the Yorkshire Early Arthritis Register

OBJECTIVE

To assess patient-reported variables as predictors of change in disease activity and disability in early rheumatoid arthritis (RA).

METHODS

Cases were recruited to the Yorkshire Early Arthritis Register (YEAR) between 1997 and 2009 (n = 1415). Predictors of the 28-joint Disease Activity Score (DAS28) and the Health Assessment Questionnaire-Disability Index (HAQ-DI) at baseline and change over 12 months were identified using multilevel models. Baseline predictors were sex, age, symptom duration, autoantibody status, pain and fatigue visual analog scales (VAS), duration of early morning stiffness (EMS), DAS28, and HAQ-DI.

RESULTS

Rates of change were slower in women than men: DAS28 fell by 0.19 and 0.17 units/month, and HAQ-DI by 0.028 and 0.023 units/month in men and women, respectively. Baseline pain and EMS had small effects on rates of change, whereas fatigue VAS was only associated with DAS28 and HAQ-DI at baseline. In patients recruited up to 2002, DAS28 reduced more quickly in those with greater pain at baseline (by 0.01 units/mo of DAS28 per cm pain VAS, p = 0.024); in patients recruited after 2002, the effect for pain was stronger (by 0.01 units/mo, p = 0.087). DAS28 reduction was greater with longer EMS. In both cohorts, fall in HAQ-DI (p = 0.006) was greater in patients with longer EMS duration, but pain and fatigue were not significant predictors of change in HAQ-DI.

CONCLUSION

Patient-reported fatigue, pain, and stiffness at baseline are of limited value for the prediction of RA change in disease activity (DAS28) and activity limitation (HAQ-DI).

Epitope Specificity of Anti-Citrullinated Protein Antibodies

Anti-citrullinated protein antibodies are primarily associated with a progressive course in the autoimmune disease rheumatoid arthritis, a disease with a chronic and inflammatory nature. These antibodies do not appear to have any strict dependency for reactivity except from the presence of the non-genetically encoded amino acid citrulline, which is the result of a posttranslational modification, catalyzed by calcium-dependent peptidylarginine deiminase enzymes. Nevertheless, several amino acids surrounding the citrulline residue notably influence antibody reactivity, especially with a central-Cit-Gly-motif being essential for antibody reactivity. Most importantly, these antibodies have been proposed to be divided into two groups, based on their ability to recognize multiple citrullinated peptides. Thus, an "overlapping" antibody group, which appears to recognize several citrullinated peptides, and a "non-overlapping" antibody group, which only recognizes a limited number of citrullinated peptides, have been proposed. Based on these findings, we suggest that antibodies recognizing several citrullinated targets, also referred to as cross-reactive antibodies, primarily are backbone-dependent, whereas less cross-reactive antibodies primarily depend on the side chains of the amino acids comprising the epitopes for stable antibody-antigen interactions, which reduces the degree of cross-reactivity significantly. Clarifying the reactivity pattern of anti-citrullinated protein antibodies may contribute to determining their true nature of origin.

Effect of early treatment on physical function in daily management of rheumatoid arthritis: a 5-year longitudinal study of rheumatoid arthritis patients in the National Database of Rheumatic Diseases in Japan

AIM

The purpose of this study was to assess 5-year changes in physical function and factors associated with improvement among patients with rheumatoid arthritis (RA) in daily clinical practice, focusing on the effect of treatments, including biologic agents, in the early stage of disease course.

METHODS

The National Database of Rheumatic Diseases by iR-net in Japan (NinJa) was searched for patients with disease duration ≤ 2 years and modified health assessment questionnaire (mHAQ) > 0 between 2004 and 2007, so that 510 patients were included in the final analysis. Multivariate-logistic regression analyses were used to identify predictors of 5-year mHAQ disability score improvement.

RESULTS

Median mHAQ score was 0.40 at baseline and decreased to a median 0.17 after 5 years. Seventy-four percent of the patients were treated with methotrexate (MTX) and 25% with biologic agents, with early use of biologic agents (within 2 years of RA onset) increasing over time. Multivariate analyses identified higher baseline Disease Activity Score of 28 joints - C-reactive protein and early use of MTX (within 1 year of RA onset) and of biologic agents (within 2 years) as significantly associated with improved mHAQ; odds ratios of the early treatment were 1.83 (P = 0.01) for MTX and 2.23 (P = 0.04) for biologic agents, respectively.

CONCLUSION

Five-year mHAQ improved in early RA patients in the NinJa database. In daily clinical management of RA, likewise in clinical trials, early administration of MTX or biologic agents is able to improve physical function outcome.

Association of a multibiomarker disease activity score at multiple time-points with radiographic progression in rheumatoid arthritis: results from the SWEFOT trial

OBJECTIVES

In rheumatoid arthritis (RA), predictive biomarkers for subsequent radiographic progression (RP) could improve therapeutic choices for individual patients. We previously showed that the multibiomarker disease activity (MBDA) score in patients with newly diagnosed RA identified patients at risk for RP. We evaluated the MBDA score at multiple time-points as a predictor of RP during 2 years of follow-up.

METHODS

A subset of patients with RA (N=220) from the Swedish Farmacotherapy (SWEFOT) trial were analysed for MBDA score, disease activity score of 28 joints (DAS28), C reactive protein (CRP) and erythrocyte sedimentation rate (ESR) at baseline (BL), month 3 and year 1, for predicting RP based on modified Sharp/van der Heijde scores at BL, year 1 and year 2.

RESULTS

Patients with persistently low MBDA (<30) scores or those with a decrease from moderate (30-44) to low MBDA scores, did not develop RP during 2 years of follow-up. The highest risk for RP during 2 years of follow-up (42%) was observed among patients with persistently high (>44) MBDA scores. Among methotrexate non-responders with a high MBDA score at BL or month 3, significantly more of those who received triple therapy had RP at year 2 compared with those who received antitumour necrosis factor therapy.

CONCLUSIONS

Measuring the MBDA score both before and during treatment in RA was useful for the assessment of individual patient risk for RP during 2 years of follow-up. In comparison with low CRP, ESR or DAS28, a low MBDA score at any time-point was associated with numerically lower proportions of RP.

TRIAL REGISTRATION NUMBER

NCT00764725.

Anti-CCP antibodies are not a marker of severity in established rheumatoid arthritis: a magnetic resonance imaging study

INTRODUCTION

The presence of anti-CCP is an important prognostic tool of rheumatoid arthritis (RA). But research is still ongoing on its relationship with disease activity and functional capacity.

OBJECTIVES

To study the relationship between anti-CCP and disease activity, functional capacity and structural damage indexes, by means of conventional radiography (CR) and magnetic resonance imaging (MRI), in cases of established RA.

METHODS

Cross-sectional study with RA patients with 1-10 disease duration. Participants underwent clinical evaluation with anti-CCP. Disease activity was assessed using the Clinical Disease Activity Index (CDAI), and functional capacity through the Health Assessment Questionnaire (HAQ). CR analysis was carried out by the Sharp van der Heijde index (SvdH), and MRI analysis by RAMRIS (Rheumatoid Arthritis Magnetic Resonance Image Scoring).

RESULTS

We evaluated 56 patients, with a median (IqR) age of 55 (47.5-60) years; 50 (89.3%) participants were female and 37 (66.1%) were positive for anti-CCP. Medians (IqR) of CDAI, HAQ, SvdH and RAMRIS were 14.75 (5.42-24.97) 1.06 (0.28-1.75), 2 (0-8) and 15 (7-35), respectively. There was no association between anti-CCP and CDAI, HAQ and SvdH and RAMRIS scores.

CONCLUSION

Our results have not established an association of anti-CCP with the severity of disease. To date, we cannot corroborate anti-CCP as a prognostic tool in patients with established RA.

Predictive value of autoantibodies from anti-CCP2, anti-MCV and anti-human citrullinated fibrinogen tests, in early rheumatoid arthritis patients with rapid radiographic progression at 1 year: results from the ESPOIR cohort

Objectives

We compared the ability of antibodies against cyclic citrullinated peptides (anti-CCP2), against mutated citrullinated vimentin (anti-MCV) and against citrullinated fibrinogen (AhFibA) to predict 1 year rapid radiographic progression (RRP; total Sharp score variation ≥5 points), in early rheumatoid arthritis (RA).

Methods

We analysed 566 patients from the ESPOIR cohort with early RA fulfilling the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria at year 1. We assayed the 3 anticitrullinated peptide antibodies (ACPA) tests on baseline sera. We compared the performance of these 3 ACPA tests to predict first-year RRP, by comparing areas under the receiver operating characteristic curves (ROCs). We assessed the 1 year RRP risk by ACPA titres. We used a logistic multivariate regression to analyse RRP risk in terms either of ACPA positivity or titre: high (>3 times the N cut-off) and low (1 to 3N).

Results

145 patients displayed RRP. Areas under the ROCs were similar (0.60) for the 3 tests. High ACPA titres were associated with 1 year RRP, whatever the test was, and with similar ORs. Low+ anti-MCV titres were not associated with 1-year RRP, whereas low+ anti-CCP2 titres (p=0.0226) and low+ AhFibA titres (p=0.0332) were significantly associated. In multivariate analysis, 1 year RRP was associated with anti-CCP2 positivity (p<0.0001), AhFibA positivity (p<0.0001) and high anti-MCV titres (p<0.0001).

Conclusions

Anti-CCP2 antibodies and AhFibA were predictive of 1 year RRP in early RA whatever their titre was, whereas only high anti-MCV antibody titres were predictive, potentially making them more discriminant to predict 1 year RRP risk.

Anticarbamylated protein antibodies are associated with long-term disability and increased disease activity in patients with early inflammatory arthritis: results from the Norfolk Arthritis Register

Objectives

Anticarbamylated protein (anti-CarP) antibodies are a novel family of autoantibodies recently identified in patients with inflammatory arthritis. The aim of this study was to investigate their association with long-term outcomes of disability and disease activity over 20 years’ follow-up in a cohort of patients with inflammatory polyarthritis (IP).

Methods

Norfolk Arthritis Register recruited adults with recent-onset swelling of ≥2 joints for ≥4 weeks from 1990 to 2009. At baseline, Health Assessment Questionnaire (HAQ) and 28 joint disease activity scores (DAS28) were obtained, and C reactive protein, rheumatoid factor (RF), anticitrullinated protein antibodies (ACPA) and anti-CarP antibodies were measured. Further HAQ scores and DAS28 were obtained at regular intervals over 20 years. Generalised estimating equations were used to test the association between anti-CarP antibody status and longitudinal HAQ and DAS28 scores; adjusting for age, gender, smoking status, year of inclusion and ACPA status. Analyses were repeated in subgroups stratified by ACPA status. The relative association of RF, ACPA and anti-CarP antibodies with HAQ and DAS28 scores was investigated using a random effects model.

Results

1995 patients were included; 1310 (66%) were female. Anti-CarP antibodies were significantly associated with more disability and higher disease activity, HAQ multivariate β-coefficient (95% CI) 0.12 (0.02 to 0.21), and these associations remained significant in the ACPA-negative subgroups. The associations of RF, ACPA and anti-CarP antibodies were found to be additive in the random effects model.

Conclusions

Anti-CarP antibodies are associated with increased disability and higher disease activity in patients with IP. Our results suggest that measurement of anti-CarP antibodies may be useful in identifying ACPA-negative patients with worse long-term outcomes. Further, anti-CarP antibody status provided additional information about RF and ACPA.

Anti-CCP antibodies are not a marker of severity in established rheumatoid arthritis: a magnetic resonance imaging study

INTRODUCTION

The presence of anti-CCP is an important prognostic tool of rheumatoid arthritis (RA). But research is still ongoing on its relationship with disease activity and functional capacity.

OBJECTIVES

To study the relationship between anti-CCP and disease activity, functional capacity and structural damage indexes, by means of conventional radiography (CR) and magnetic resonance imaging (MRI), in cases of established RA.

METHODS

Cross-sectional study with RA patients with 1-10 years of disease duration. Participants underwent clinical evaluation with anti-CCP. Disease activity was assessed using the Clinical Disease Activity Index (CDAI), and functional capacity through the Health Assessment Questionnaire (HAQ). CR analysis was carried out by the Sharp van der Heijde index (SvdH), and MRI analysis by RAMRIS (Rheumatoid Arthritis Magnetic Resonance Image Scoring).

RESULTS

We evaluated 56 patients, with a median (IqR) age of 55 (47.5-60.0) years; 50 (89.3%) participants were female and 37 (66.1%) were positive for anti-CCP. Medians (IqR) of CDAI, HAQ, SvdH and RAMRIS were 14.75 (5.42-24.97) 1.06 (0.28-1.75), 2 (0-8) and 15 (7-35), respectively. There was no association between anti-CCP and CDAI, HAQ and SvdH and RAMRIS scores.

CONCLUSION

Our results have not established an association of anti-CCP with the severity of disease. To date, we cannot corroborate anti-CCP as a prognostic tool in patients with established RA.

ACPA-positive primary Sjögren's syndrome: true primary or rheumatoid arthritis-associated Sjögren's syndrome?

Objectives

Anticyclic citrullinated protein antibodies (ACPA) are highly specific of rheumatoid arthritis (RA). However, they have also been detected in 5–10% of primary Sjögren's syndrome (pSS). We compared ACPA-positive and negative patients with pSS and assessed the risk of evolution to RA.

Patients and methods

ACPA-positive and negative patients with pSS were included in this study. For ACPA-positive patients, clinical and radiological re-evaluation was systematically performed after at least 5 years of follow-up. Diagnosis was reassessed at the end of the follow-up to identify patients that developed RA according to the American College of Rheumatology 1987 classification criteria.

Results

At inclusion in the cohort 16 patients with pSS were ACPA positive and 278 were ACPA negative. ACPA-positive patients, had more frequently arthritis (43.7% vs 12.2%; p=0.003) but not arthralgias. They also had more frequent lung involvement (25% vs 8.1%; p=0.05). After median follow-up of 8 (5–10) years, 7/16 (43.8%) patients developed RA including 5 (31.25%) with typical RA erosions. Elevation of acute phase reactants at inclusion was the only parameter associated with progression to erosive RA.

Conclusions

Median term follow-up of ACPA-positive patients with pSS showed that almost half of them developed RA, particularly in the presence of elevation of acute phase reactants. These results support the usefulness of a close radiological monitoring of these patients for early detection of erosive change not to delay initiation of effective treatment. Indeed, number of these patients with ACPA-positive pSS may actually have RA and associated SS.

Associations of rheumatoid factor and anti-citrullinated peptide antibody with disease progression and treatment outcomes in patients with rheumatoid arthritis

The objective of this study was to investigate the association of rheumatoid factor (RF) and anti-citrullinated peptide antibodies (ACPA) status with disease progression and treatment outcomes in patients with rheumatoid arthritis (RA). A total of 276 adult patients who fulfilled the American College of Rheumatology 1987 classification criteria for RA were recruited from the Rheumatology clinic, Siriraj Hospital, from January 2011 to December 2012. Demographic, clinical, and laboratory data were collected at baseline and every 3 months up to 1 year of follow-up. RF and ACPA were measured at baseline. Radiography of the hands and feet was performed at baseline and 1 year. Patients with RF+/ACPA+ had significantly more severe disease activity and impaired functional status than those who had RF-/ACPA-. Although they received more aggressive treatment with methotrexate and combination of non-biologic, disease-modifying antirheumatic drug than other groups, fewer patients in this group achieved remission at 1 year of follow-up, especially when compared to RF-/ACPA- group (12 vs. 18 %). For radiographic erosion, patients with the presence of either RF or ACPA had a higher proportion of hand erosion than seronegative patients at baseline (77, 73, 83, and 32 %, p < 0.001 for RF+/ACPA+, RF+/ACPA-, RF-/ACPA+, and RF-/ACPA-, respectively). After 1 year of follow-up, patients who developed new erosion at the hands were more prevalent in RF+/ACPA+ (32 %) and RF+/ACPA- (33 %) groups. However, "newly developed" feet erosion was most common in RF+/ACPA- group (40 %) than in other groups. Patients with positive either RF or ACPA or both have more severe and aggressive disease that requires intensive treatment to improve outcomes.

Meta-analysis: diagnostic accuracy of anti-cyclic citrullinated peptide antibody for juvenile idiopathic arthritis

OBJECTIVE

To estimate the diagnostic accuracy of the anti-CCP test in JIA and to evaluate factors associated with higher accuracy.

METHODS

Two investigators performed an extensive search of the literature published between January 2000 and January 2014. The included articles were assessed by the Quality Assessment of Diagnostic Accuracy Studies tool. The meta-analysis was performed using a summary ROC (SROC) curve and a bivariate random-effect model to estimate sensitivity and specificity across studies.

RESULTS

The bivariate meta-analysis yielded a pooled sensitivity and specificity of 10% (95% confidence interval (CI): 6.0%-15.0%) and 99.0% (95% CI: 98.0%-100.0%). The area under the SROC curve was 0.96. Sensitivity estimates were highly heterogeneous, which was partially explained by the higher sensitivity in the rheumatoid factor-positive polyarthritis (RF+ PA) subtype (48.0%; 95% CI: 31.0%-65.0%) than in the other subtypes (17.0%; 95% CI: 14.0%-20.0%) and the higher sensitivity of the Inova assay (17.0%; 95% CI: 14.0%-20.%%) than the other assays (0.05%; 95% CI: 2.0%-11.0%).

CONCLUSIONS

Anti-CCP antibody test has a high specificity for the diagnosis of JIA. The sensitivity of this test is low and varies across populations but is higher in RF+ PA than in other JIA subtypes.

Rheumatoid factor and anti-citrullinated protein antibody positivity, but not level, are associated with increased mortality in patients with rheumatoid arthritis: results from two large independent cohorts

Introduction

This study aimed to investigate rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) status and levels as predictors of mortality in two large cohorts of patients with early inflammatory arthritis (EIA).

Methods

Data from the Norfolk Arthritis Register (NOAR) and Leiden Early Arthritis Clinic (EAC) cohorts were used. At baseline, patients had demographic data and smoking status recorded; RF, ACPA and inflammatory markers were measured in the local laboratories. Patients were flagged with national death registers until death or censor date. Antibody status was stratified as negative, low or high positive by RF and ACPA levels individually. In addition, patients were grouped as seronegative, RF positive, ACPA positive or double antibody (RF and ACPA) positive. Cox regression models explored associations between antibody status and mortality adjusting for age, sex, smoking status, inflammatory markers and year of enrolment.

Results

A total of 4962 patients were included, 64% were female. Median age at onset was 56 (NOAR) and 54 (EAC) years. In NOAR and EAC respectively, 35% and 42% of patients were ACPA/RF positive. When antibody status was stratified as negative, low or high positive, there were no consistent findings between the two cohorts. Double antibody positivity was associated with excess mortality in both cohorts compared to seronegative patients: NOAR and EAC respective adjusted HR (95% confidence interval) 1.35 (1.09 to 1.68) and 1.58 (1.16 to 2.15).

Conclusions

Patients with EIA who are seropositive for both RF and ACPA have increased mortality compared to those who are single positive or seronegative. Antibody level in seropositive patients was not consistently associated with excess mortality.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-014-0483-3) contains supplementary material, which is available to authorized users.

Arthritis and bone loss: a hen and egg story

PURPOSE OF REVIEW

In this review, we will discuss the relation between bone loss and inflammation in rheumatoid arthritis.

RECENT FINDINGS

We highlight recent discoveries on the pathomechanisms of bone loss in rheumatoid arthritis and challenge traditional concepts by suggesting that bone loss may precede inflammation.

SUMMARY

During the clinical course of rheumatoid arthritis, inflammation is the key trigger for progressive local and systemic bone damage. Inflammatory cytokines induce the expression of molecules supporting the differentiation of osteoclasts, which are the primary bone-resorbing cells. However, bone loss can be observed in patients with recent-onset rheumatoid arthritis, suggesting that the start of the destructive phase of disease may be much earlier than previously expected. Recent data suggest that bone loss already starts during the autoimmune phase of the disease long before inflammation starts. Antibodies against citrullinated proteins thereby seem to be an important trigger for bone loss in the preclinical disease phase of rheumatoid arthritis. Although traditional concepts preferred a 'hen-egg' concept with inflammation coming first, later triggering bone loss, new data suggest an alternative 'egg-hen' concept, where bone loss arises before the clinical disease onset and may be important for priming of the joint for susceptibility to chronic inflammation.

Health Assessment Questionnaire disability progression in early rheumatoid arthritis: systematic review and analysis of two inception cohorts

Objective

The Health Assessment Questionnaire is widely used for patients with inflammatory polyarthritis (IP) and its subset, rheumatoid arthritis (RA). In this study, we evaluated the progression of HAQ scores in RA (i) by systematically reviewing the published literature on the methods used to assess changes in functional disability over time and (ii) to study in detail HAQ progression in two large prospective observational studies from the UK.

Methods

Data from two large inception cohorts, ERAS and NOAR, were studied to determine trajectories of HAQ progression over time by applying latent class growth models (LCGMs) to each dataset separately. Age, sex, baseline DAS28, symptom duration, rheumatoid factor, fulfilment of the 1987 ACR criteria and socio-economic status (SES) were included as potential predictors of HAQ trajectory subgroup membership.

Results

The literature search identified 49 studies showing that HAQ progression has mainly been based on average changes in the total study population. In the HAQ progression study, a LCGM with four HAQ trajectory subgroups was selected as providing the best fit in both cohorts. In both the cohorts, older age, female sex, longer symptom duration, fulfilment of the 1987 ACR criteria, higher DAS28 and lower SES were associated with increased likelihood of membership of subgroups with worse HAQ progression.

Conclusion

Four distinct HAQ trajectory subgroups were derived from the ERAS and NOAR cohorts. The fact that the subgroups identified were nearly identical supports their validity. Identifying distinct groups of patients who are at risk of poor functional outcome may help to target therapy to those who are most likely to benefit.

Pretreatment multi-biomarker disease activity score and radiographic progression in early RA: results from the SWEFOT trial

Objectives

Prediction of radiographic progression (RP) in early rheumatoid arthritis (eRA) would be very useful for optimal choice among available therapies. We evaluated a multi-biomarker disease activity (MBDA) score, based on 12 serum biomarkers as a baseline predictor for 1-year RP in eRA.

Methods

Baseline disease activity score based on erythrocyte sedimentation rate (DAS28-ESR), disease activity score based on C-reactive protein (DAS28-CRP), CRP, MBDA scores and DAS28-ESR at 3 months were analysed for 235 patients with eRA from the Swedish Farmacotherapy (SWEFOT) clinical trial. RP was defined as an increase in the Van der Heijde-modified Sharp score by more than five points over 1 year. Associations between baseline disease activity measures, the MBDA score, and 1-year RP were evaluated using univariate and multivariate logistic regression, adjusted for potential confounders.

Results

Among 235 patients with eRA, 5 had low and 29 moderate MBDA scores at baseline. None of the former and only one of the latter group (3.4%) had RP during 1 year, while the proportion of patients with RP among those with high MBDA score was 20.9% (p=0.021). Among patients with low/moderate CRP, moderate DAS28-CRP or moderate DAS28-ESR at baseline, progression occurred in 14%, 15%, 14% and 15%, respectively. MBDA score was an independent predictor of RP as a continuous (OR=1.05, 95% CI 1.02 to 1.08) and dichotomised variable (high versus low/moderate, OR=3.86, 95% CI 1.04 to 14.26).

Conclusions

In patients with eRA, the MBDA score at baseline was a strong independent predictor of 1-year RP. These results suggest that when choosing initial treatment in eRA the MBDA test may be clinically useful to identify a subgroup of patients at low risk of RP.

Trial registration number

WHO database at the Karolinska Institute: CT20080004; and clinicaltrials.gov: NCT00764725.

Resistin in inflammatory and degenerative rheumatologic diseases. Relationship between resistin and rheumatoid arthritis disease progression

AIMS OF THE STUDY

To assess and compare resistin levels in the serum and synovial fluid of patients with rheumatoid arthritis (RA; an inflammatory rheumatologic disease) and osteoarthritis (OA; a degenerative rheumatologic disease) and to study the relationship between resistin levels and prognostic factors of RA disease progression.

PATIENTS AND METHODS

This study included a total of 50 patients: 25 with RA and 25 with OA. Full case history was documented for all patients and all underwent a thorough clinical examination and laboratory testing. Body mass index (BMI) values were also calculated. Radiographs were made of OA patients' knees and RA patients' hands. Disease Activity Score 28 (DAS28) was calculated for RA patients. Serum and synovial fluid samples were obtained from the effused knees of all patients and tested for resistin level.

RESULTS

Serum resistin levels were higher in RA patients than in those with OA (p < 0.01). Synovial fluid resistin levels were also higher in RA than OA patients (p < 0.001). While serum resistin levels correlated with Larsen score and total leukocyte count (TLC), synovial fluid resistin levels correlated with rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) levels in addition to Larsen score and TLC.

CONCLUSION

Resistin levels were found to be higher in the serum and synovial fluid of RA patients than in those with OA. This may suggest a role for resistin in inflammatory rheumatologic diseases. The observed statistically significant correlation between synovial fluid resistin levels and RF, ACPA and Larsen score may suggest that high synovial fluid resistin levels can be considered a poor prognostic factor for RA progression. However, further studies employing a larger cohort of patients are needed to confirm the relevance of resistin as a prognostic marker in RA patients.

Anticitrullinated protein antibodies and rheumatoid factor fluctuate in early inflammatory arthritis and do not predict clinical outcomes

OBJECTIVE

In inflammatory arthritis, rheumatoid factor (RF) and anticitrullinated protein antibodies (ACPA) are believed to be associated with more severe clinical outcomes. Our objective was to determine whether ACPA and RF remain stable in early inflammatory arthritis and whether their trajectories over time or baseline levels predicted clinical outcomes.

METHODS

The study population consisted of patients enrolled in the Canadian Early Arthritis Cohort Study with baseline and at least 12-month followup values of RF and ACPA. Primary outcomes were Disease Activity Score (DAS) remission and the presence of erosions at 12 and 24 months. Other objectives included swollen joint count, Health Assessment Questionnaire score, and DAS.

RESULTS

At baseline, 225/342 (66%) patients were ACPA-positive and 334/520 (64%) were RF-positive. At 24 months, 15/181 (8%) ACPA-positive patients became negative. A larger number of patients changed from ACPA-negative to positive: 13/123 (11%). For RF, fluctuations were more common: 67/240 (28%) reverted from positive to negative and 21/136 (18%) converted from negative to positive. RF and ACPA fluctuations did not predict disease outcomes. Patients who remained ACPA-positive throughout followup were more likely to have erosive disease (OR 3.86, 95% CI 1.68, 8.92).

CONCLUSION

RF and ACPA have the potential to revert and convert during the early course of disease. Fluctuations in RF and ACPA were not associated with clinical outcomes.

Palindromic Rheumatism with Positive Anticitrullinated Peptide/Protein Antibodies Is Not Synonymous with Rheumatoid Arthritis. A Longterm Followup Study

Objective.

To analyze longterm progression to rheumatoid arthritis (RA) and the predictive value of anticitrullinated peptide/protein antibodies (ACPA) in palindromic rheumatism (PR).

Methods.

We selected all patients in our clinic with PR who had at least 1 ACPA measurement. We included only patients with pure PR, defined as no evidence of associated rheumatic disease at the first serum ACPA measurement. Clinical characteristics, serum ACPA levels, duration of PR until serum ACPA measurement, and total followup time were recorded. The outcome variable was the definitive diagnosis of RA. The prognostic value of ACPA status in pure PR for a definite diagnosis of RA was analyzed by different statistical methods.

Results.

Seventy-one patients (54 women/17 men) with a PR diagnosis were included. Serum ACPA were positive in 52.1%. After a mean followup of 7.6 ± 4.7 years since the first ACPA measurement, 24 patients (33.8%) progressed to chronic disease: 22% RA, 5.6% systemic lupus erythematosus, and 5.6% other diseases. The positive likelihood ratio of ACPA status for RA was 1.45, and the area under the receiver-operating characteristic curve of ACPA titers was 0.60 (95% CI 0.45−0.75). Progression to RA was more frequently seen in ACPA-positive than in ACPA-negative patients (29.7% vs 14.7%), but the difference was not significant (hazard ratio 2.46, 95% CI 0.77−7.86). Mean ACPA levels of patients with pure PR did not differ significantly from those of patients who progressed to RA.

Conclusion.

ACPA are frequently found in the sera of patients with PR, and a significant proportion of these patients do not progress to RA in the long term.

The association of anti-CCP1 antibodies with disease activity score 28 (DAS-28) in rheumatoid arthritis

Background:

Rheumatoid arthritis (RA) is one of the most frequent autoimmune diseases in the world which affect about 1% of people. Measurement of the anti-CCP1 antibody titer in these patients is one of the new tests that is available in our country and in the multiple studies has been shown to be more specific than rheumatoid factor in the diagnosis of RA (97%). This test becomes positive in early stage of disease and it has a high predictive value. The aim of our study was to determine the relationship between anti-CCP1 antibody and disease activity score 28 (DAS-28) in patients with rheumatoid arthritis.

Materials and Methods:

A cross-sectional study was performed in 90 patients with RA for evaluating the relation between anti-CCP1 antibody titer and DAS-28, patients were selected by consecutive method; serum samples were collected from patients. Anti-CCP1 antibody was measured by the corresponding enzyme-linked immunosorbent assay. Additionally, erythrocyte sedimentation rates (ESR), rheumatoid factor (RF), DAS-28, visual analog scale (VAS) were determined in patients with RA. Statistical analysis performed with t-test and Pearson's correlations coefficient.

Results:

Anti-CCP1 level was associated with DAS-28 (P<0.001, r=0.35). The largest linear correlation was between anti-CCP1 antibody levels and VAS; it means that higher titers of anti-CCP1 antibody are associated with more painful joints in our patients. The average of DAS-28 in our positive and negative anti-CCP1 antibody patients was 5.07±1.1 and 3.5±1.5, respectively (P<0.05).

Conclusion:

There was moderate correlation between anti-CCP1 titer and DAS-28.

Anticitrullinated Protein Antibody, But Not Its Titer, Is a Predictor of Radiographic Progression and Disease Activity in Rheumatoid Arthritis

Objective.

To study the contribution of anticitrullinated protein antibody (ACPA), and especially of its titer, to radiographic progression and disease activity in rheumatoid arthritis (RA).

Methods.

Patients with RA (n = 396) who attended a Japanese clinic within 2 years after disease onset were divided into the following groups according to second-generation (ACPA-2) ACPA titer on their first visit: negative (0–4.4 U/ml; n = 115), low-positive (4.5–121 U/ml; n = 141), and high-positive (> 121 U/ml; n = 140). The ACPA-2-positive groups were further subdivided into lowest (4.5–32 U/ml), low (33–121 U/ml), high (122–277 U/ml), and highest (> 278 U/ml) quartiles. All patients were treated with disease-modifying antirheumatic drugs (DMARD) including methotrexate, but not biologics. Subsequent radiographic progression and disease activity for 2 years were prospectively evaluated using the van der Heijde-modified Sharp score (SHS) and 28-joint Disease Activity Score (DAS28).

Results.

After treatment with DMARD, the disease activity (including number of swollen joints, number of tender joints, duration of morning stiffness, DAS28-erythrocyte sedimentation rate, and DAS28-C-reactive protein) was significantly decreased in all patient groups. Disease activity and radiographic progression as revealed by the change in SHS remained relatively higher in the ACPA-2 low- and high-positive groups as compared with the ACPA-2-negative group. The relationship between the titer of ACPA-2 at baseline and subsequent radiographic progression was not exactly linear, and the extent of disease activity or radiographic progression was similar between ACPA-2 low- and high-positive groups and also between ACPA-2 lowest- and highest-positive quartile groups. The results were demonstrable in cumulative SHS probability plots, and also repeatable in seronegative patients, which indicated that the titer of ACPA-2 is not a predictor of disease activity or radiographic progression in RA, and ACPA-2-negative patients, especially those with < 3 U/ml, showed minimal radiographic progression.

Conclusion.

Presence of ACPA-2, but not its titer, at baseline is a predictor of radiographic progression or disease activity, where radiographic progression is minimal in ACPA-2-negative patients.

The future of rheumatoid arthritis and hand surgery - combining evolutionary pharmacology and surgical technique

Rheumatoid arthritis is a systemic autoimmune disease of uncertain aetiology, which is characterized primarily by synovial inflammation with secondary skeletal destructions.Rheumatoid Arthritis is diagnosed by the presence of four of the seven diagnostic criteria, defined by The American College of Rheumatology.Approximately half a million adults in the United Kingdom suffer from rheumatoid arthritis with an age prevalence between the second and fourth decades of life; annually approximately 20,000 new cases are diagnosed.The management of Rheumatoid Arthritis is complex; in the initial phase of the disease it primarily depends on pharmacological management. With disease progression, surgical input to correct deformity comes to play an increasingly important role. The treatment of this condition is also intimately coupled with input from both the occupational therapists and physiotherapy.

Production of autoantibodies against citrullinated antigens/peptides by human B cells

Autoantibodies against citrullinated protein Ags (ACPA) are associated with the development of rheumatoid arthritis (RA). This immune response against citrullinated protein Ags, which is thought to be facilitated by certain MHC HLA-DR alleles, is highly specific for this disease and has been speculated to be involved in the pathogenesis. We have previously studied cultures of B cells for the production of Abs against HLA Ags. The aim of the current study was to examine the role of B cells in the production of ACPA in patients with RA. Peripheral blood B cells from RA patients and healthy people were cultured with EL4-B5, a murine cell line expressing human CD40L, and with T cell factors to stimulate the in vitro production of Abs by B cells isolated from peripheral blood. ACPA were produced by cultured B cells from RA patients, as determined by reactivity to cyclic citrullinated peptide (CCP). The results showed that 22% of the healthy persons tested also had B cells that could produce ACPA. Patients with HLA-DR alleles carrying the RA-associated shared epitope appeared to have more B cells with autoimmune potential for CCP than those without such HLA alleles (odds ratio 8.1, p = 0.001). In healthy individuals, anti-CCP-producing B cells were also observed more frequently if the RA-associated MHC genes were present (odds ratio 8.0, p = 0.01). Analysis of B cells in cultures may shed light on the interaction of genetic and environmental factors in the development of RA.

Inflammation and autoantibody markers identify rheumatoid arthritis patients with enhanced clinical benefit following rituximab treatment

OBJECTIVE

Rituximab significantly improves the signs and symptoms of rheumatoid arthritis (RA) and slows the progression of joint damage. The aim of this study was to identify clinical characteristics and biomarkers that identify patients with RA in whom the clinical benefit of rituximab may be enhanced.

METHODS

The study group comprised 1,008 RA patients from 2 independent randomized placebo-controlled phase III clinical trials (REFLEX [Randomized Evaluation of Long-Term Efficacy of Rituximab in Rheumatoid Arthritis] and SERENE [Study Evaluating Rituximab's Efficacy in Methotrexate Inadequate Responders]). A novel threshold selection method was used to identify baseline candidate biomarkers present in at least 20% of patients that enriched for placebo-corrected American College of Rheumatology 50% improvement (ACR50 response; a high clinical efficacy bar) at week 24 after the first course of rituximab.

RESULTS

The presence of IgM rheumatoid factor (IgM-RF), IgG-RF, IgA-RF, and IgG anti-cyclic citrullinated peptide (anti-CCP) antibodies together with an elevated C-reactive protein (CRP) level were associated with enhanced placebo-corrected ACR50 response rates in the REFLEX patients with RA who had an inadequate response to anti-tumor necrosis factor therapies. These findings were independently replicated using samples from patients in SERENE who had an inadequate response to disease-modifying antirheumatic drug treatment. The combination of an elevated baseline CRP level together with an elevated level of any RF isotype and/or IgG anti-CCP antibodies was further associated with an enhanced benefit to rituximab.

CONCLUSION

The presence of any RF isotype and/or IgG anti-CCP autoantibodies together with an elevated CRP level identifies a subgroup of patients with RA in whom the benefit of rituximab treatment may be enhanced. Although the clinical benefit of rituximab was greater in the biomarker-positive population compared with the biomarker-negative population, the clinical benefit of rituximab compared with placebo was also clinically meaningful in the biomarker-negative population.

IgG glycosylation changes and MBL2 polymorphisms: associations with markers of systemic inflammation and joint destruction in rheumatoid arthritis

OBJECTIVE

To examine whether IgG glycosylation changes and MBL2 genotypes are associated with systemic inflammation and joint destruction in rheumatoid arthritis (RA).

METHODS

IgG N-glycan content was determined from serum in 118 patients with RA by high-throughput glycan analysis using normal-phase high-pressure liquid chromatography. MBL2 extended genotypes (YA/YA, YA/XA, XA/XA, YA/YO, XA/YO, YO/YO) were determined. Systemic inflammation was assessed by serum levels of C-reactive protein (CRP), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α). Joint destruction was assessed by total Sharp score (TSS) and alloplastic surgery records.

RESULTS

IgG hypogalactosylation was significantly correlated to IL-6 (Spearman's rho = 0.32, p < 0.001), CRP (Spearman's rho = 0.31, p < 0.001), TSS (Spearman's rho = 0.25, p = 0.01), and alloplastic replacement of joints (Spearman's rho = 0.18, p = 0.05). In multivariate analysis including age, CRP, anticitrullinated protein antibodies (ACPA), and other confounders, IgG hypogalactosylation was significantly associated with TSS (p = 0.014) and alloplastic joint replacement (OR 76.5, p = 0.041) in patients homozygous for the high expression MBL2 genotype YA/YA, but not in carriers of lower expression genotypes.

CONCLUSION

Decreased galactosylation of IgG correlated to markers of inflammation, i.e., IL-6 and CRP. Only in patients homozygous for high expression of the MBL2 genotype YA/YA was IgG hypogalactosylation associated with markers of joint destruction. Our results suggest that inflammation-associated decreased galactosylation of IgG combined with high expression MBL2 genotypes are involved in the pathophysiology of RA.

A comparative study on the diversity of clinical features between the sero-negative and sero-positive rheumatoid arthritis patients

To investigate the similarities and differences in clinical features between the sero-negative and sero-positive rheumatoid arthritis (RA) patients. Two hundred and sixty-two RA patients who fulfilled the 1987 ACR RA Classification Criteria were enrolled into this study. They were divided into sero-negative and sero-positive group depending on the presence or absence of rheumatoid factor (RF) and anti-cyclic citrullinate peptide (anti-CCP). The clinical features were compared between these two groups. Forty-six (17.6%) RA patients were classified as sero-negative group. The disease onset of sero-negative RA patients was later than that of sero-positive RA patients (52.4 ± 15.9 vs. 47.4 ± 15.5 years, P < 0.05). At the end of the first 2 years after disease onset, bone erosion shown in the hand X-ray occurred in 4 out of 24 (16.7%) patients with sero-negative RA. However, only 5.2% (5/97) patients with sero-positive RA developed bone erosion (P < 0.05). In the sero-positive RA patients, the titer of RF was correlated with swollen joint counts (SJC), tender joint counts (TJC), erythrocyte sedimentation rate (ESR), and disease activity score in 28 joints (DAS28) (P < 0.05), but anti-CCP was not. Sero-negative and sero-positive RA are probably two distinct disease subtypes driven by different mechanisms.

FoxP3 mRNA splice forms in synovial CD4+ T cells in rheumatoid arthritis and psoriatic arthritis

Our aim was to elucidate the relative amount of the different splice forms of FoxP3 mRNA in CD4+ T cells in peripheral blood (PB) compared to synovial fluid (SF) in RA and PsA patients. FoxP3 mRNA was measured using a quantitative real-time PCR method. CD4+ T cells were isolated from 17 paired samples of PB and SF from RA and PsA patients, and PB from 10 controls. FoxP3fl and FoxP3Δ2 mRNA was significantly increased (6.7 and 2.1-fold, respectively) in PB CD4+ T cells from RA patients compared to controls. FoxP3fl and Δ2 mRNA in SF CD4+ T cells was increased compared to controls in sero-negative RA and PsA, but not in sero-positive RA patients, who had a high FoxP3 expression in both PB and SF. The FoxP3Δ2Δ7 mRNA was barely detectable in patient samples, and not at all in healthy individuals. We provide evidence of an increased expression of FoxP3 splice forms in synovial CD4+ T cells from RA patients. A skewed, high expression profile of FoxP3, but not CTLA-4, in sero-negative RA and PsA, indicates that synovial CD4+ T cells may represent unique subsets of T cells which have been induced locally or selectively recruited to the joint.

How does age at onset influence the outcome of autoimmune diseases?

The age at onset refers to the time period at which an individual experiences the first symptoms of a disease. In autoimmune diseases (ADs), these symptoms can be subtle but are very relevant for diagnosis. They can appear during childhood, adulthood or late in life and may vary depending on the age at onset. Variables like mortality and morbidity and the role of genes will be reviewed with a focus on the major autoimmune disorders, namely, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), type 1 diabetes mellitus (T1D), Sjögren's syndrome, and autoimmune thyroiditis (AITD). Early age at onset is a worst prognostic factor for some ADs (i.e., SLE and T1D), while for others it does not have a significant influence on the course of disease (i.e., SS) or no unanimous consensus exists (i.e., RA and MS).

HLA-DRB1 shared epitope genotyping using the revised classification and its association with circulating autoantibodies, acute phase reactants, cytokines and clinical indices of disease activity in a cohort of South African rheumatoid arthritis patients

Introduction

The revised shared epitope (SE) concept in rheumatoid arthritis (RA) is based on the presence (S) or absence (X) of the SE RAA amino acid motif at positions 72 to 74 of the third hypervariable region of the various human leucocyte antigen (HLA)-DRB1 alleles. The purpose of this study was to investigate SE subtypes on the basis of the American College of Rheumatology 1987 revised criteria for the classification of RA in a cohort of South African RA patients (n = 143) and their association with clinical and circulating biomarkers of disease activity (autoantibodies, acute phase reactants and cytokines).

Methods

Genomic DNA was analysed using high-resolution recombinant sequence-specific oligonucleotide PCR typing of the HLA-DRB1 allele. Subtypes of the SE were classified according to the amino acids at positions 72 to 74 for the RAA sequence, and further sub-divided according to the amino acids at positions 70 and 71, which either contribute to (S2, S3P), or negate (S1, S3D) RA susceptibility. Disease activity was assessed on the basis of (1) Disease Activity Score in 28 joints using C-reactive protein (CRP), (2) rheumatoid factor (RF), (3) CRP and (4) serum amyloid A by nephelometry, anticyclic citrullinated peptide antibodies (aCCP) by an immunofluorometric procedure, and cytokines by multiplex bead array technology.

Results

Of the 143 RA patients, 81 (57%) were homozygous (SS) and 50 (35%) were heterozygous (SX) for the SE alleles with significant overexpression of S2 and S3P (respective odds ratios (ORs) 5.3 and 5.8; P < 0.0001), and 12 (8%) were classified as no SE allele (XX). Both the SS and SX groups showed a strong association with aCCP positivity (OR = 10.2 and P = 0.0010, OR = 9.2 and P = 0.0028, respectively) relative to the XX group. Clinical scores and concentrations of the other biomarkers of disease activity (RF, CRP and T helper cell type 1 (Th1), Th2, macrophage and fibroblast cytokines) were also generally higher in the SS group than in the SX and XX groups.

Conclusions

RA susceptibility alleles investigated according to revised criteria for the classification of RA were significantly increased in South African RA patients and strongly associated with aCCP in particular as well as with circulating cytokines and disease severity.

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.

Role of anti-citrullinated protein antibodies in diagnosis and prognosis of rheumatoid arthritis

Antibodies to citrullinated proteins/peptides (ACPAs) are the second serological marker to have recently been included in the 2010 ACR/EULAR Rheumatoid Arthritis (RA) Classification Criteria, which are focused on early diagnosis and therapy. This review discusses their history and some clinical aspects of ACPAs, focusing on the diagnostic utility of anti-cyclic citrullinated peptide (anti-CCP) antibodies as a marker of RA as compared to the widely used rheumatoid factor (RF). Simultaneously, this review aims to raise physician awareness and interest in anti-citrullinated vimentin antibody (anti-Sa/anti-MCV), another member of the ACPA family, which appears to have a better predictive value as a marker of RA than anti-CCP or RF and correlates closely with disease activity and therapeutic response among patients with RA.

Antibodies to a new viral citrullinated peptide, VCP2: fine specificity and correlation with anti-cyclic citrullinated peptide (CCP) and anti-VCP1 antibodies

Anti-citrullinated protein/peptide antibodies (ACPA) are a hallmark of rheumatoid arthritis (RA) and can be measured using different citrullinated substrates. In this paper we describe a new viral citrullinated peptide - VCP2 - derived from the Epstein-Barr virus-encoded protein EBNA-2 and analyse its potential as substrate for ACPA detection. Analysing sera from 100 RA patients and 306 controls, anti-VCP2 immunoglobulin (Ig)G were found in 66% of RA sera, IgM in 46% and IgA in 39%, compared with less than 3% of control sera. Anti-VCP2 IgG was associated with erosive arthritis, the presence of rheumatoid factor and anti-VCP1 and anti-cyclic citrullinated peptide (CCP) antibodies. Anti-VCP2 antibodies were detected in 1% and anti-VCP1 antibodies in 4% of CCP-negative RA sera; conversely, 3% of the VCP-negative sera were CCP-positive. Taken together, these data suggest that VCP2 could offer a valuable tool for ACPA detection. Inhibition assays showed that two non-overlapping epitopes - a citrulline-glycine stretch shared between VCP1 and VCP2 and the N-terminal portion of the VCP2 sequence - were targeted by anti-VCP2 antibodies. Moreover, in some RA sera that tested positive in CCP and VCP2 assays, preincubation with VCP2 inhibited binding to CCP, whereas in other sera the binding was unaffected. Thus, the reactivity with more than one ACPA substrate might be due in some RA patients to antibody populations with different specificities, and in others to cross-reactive antibody populations. Finally, affinity-purified anti-VCP2 antibodies immunoprecipitated deiminated Epstein-Barr virus nuclear antigen (EBNA-2) from an EBNA-2-transfected cell line, suggesting that viral sequences may be involved in the generation of the ACPA response.

The prevalence of rheumatoid factor isotypes and anti-cyclic citrullinated peptides in Malaysian rheumatoid arthritis patients

AIM

The purpose of this study is to compare the prevalence of rheumatoid factor (RF) isotypes and second generation anti-cyclic citrullinated peptides (anti-CCP) in Malaysian rheumatoid arthritis (RA) patients.

METHODS

In this cross-sectional study, 147 established RA patients from three ethnic groups were recruited from a major rheumatology clinic in Malaysia. Enzyme-linked immunosorbent assays (ELISA) for serum RF isotypes IgA, IgG and IgM as well as second-generation anti-CCP were performed and the prevalence of each auto-antibody was compared in the three ethnic groups.

RESULTS

The anti-CCP was the most prevalent auto-antibody in each of the ethnic groups, followed closely by RF IgM and RF IgG. Rheumatoid factor IgA was the least prevalent across all three ethnic groups. The anti-CCP-RF IgM combination provided the best test sensitivity. Seroprevalence of anti-CCP was strongly associated with the presence of each of the RF isotypes. The seroprevalence of RF and anti-CCP did not increase or decrease with advancing age, age at onset and disease duration.

CONCLUSION

When used alone, anti-CCP provides a diagnostic advantage over RF IgM on the basis of test sensitivity. Considering the high cost of the anti-CCP assay, step-wise serum testing with IgM RF followed by anti-CCP may provide a more economically sensible option to optimize test sensitivity for RA.

Prognostic Factors of Radiological Damage in Rheumatoid Arthritis: A 10-year Retrospective Study

Objective.

To describe the longterm clinical and radiological outcomes in rheumatoid arthritis (RA) in a cohort in northwestern Greece; and to investigate predictive factors of radiological damage at the 10-year followup in patients with RA.

Methods.

We studied the disease course and outcome of 144 patients with RA and radiographs of the hands and wrists available at baseline and at 10 years. Baseline measurements and time-averaged measures of swollen joint count (SJC) and inflammatory markers [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)] were tested in univariate analysis, and then those presenting a statistically significant association with either Larsen score at 10 years or annual progression rate were included in 2 logistic regression models in order to determine relevant independent prognostic factors.

Results.

A significant clinical improvement was noted, associated with a decrease of inflammatory markers along the timepoints. Larsen score and the number of erosive joints were increased. In the univariate analysis, both final Larsen score at 10 years and accelerated annual radiological progression rate were significantly associated with baseline radiographic measurements (Larsen score and number of erosive joints), the presence of autoantibodies [anticyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factor of IgA and IgM isotype], disease duration, and time-averaged measures of ESR, CRP, and SJC. In the logistic regression analysis, the baseline Larsen score, anti-CCP antibodies, and time-averaged CRP presented significant and independent associations with Larsen score at 10 years. An accelerated annual radiological progression rate was also predicted by baseline Larsen score and time-averaged measures of SJC and CRP.

Conclusion.

Despite clinical improvement, the radiologic progression of RA continues over time, because of the underlying inflammatory process. Baseline radiographic damage, anti-CCP antibodies, and time-averaged CRP constitute the main predictive factors of poor radiologic outcome in the long term.