Different properties of ACPA and IgM-RF derived from a large dataset: further evidence of two distinct autoantibody systems

Different Clinical Relevance of Anti-Citrullinated Protein Antibodies in RA Patients

The objective of the study was to find a potential relationship between ACPAs and disease activity, bone destruction, and ACPA responses to various therapeutic regimens. The study included 232 patients with rheumatoid arthritis (RA); 90 patients had early RA, and 142 patients had an advanced stage of the disease. 77 (85.6%) patients with early RA were highly positive for anti-CCP, and 29 (70.7%) patients were highly positive for anti-MCV. A positive correlation was found between anti-MCV and DAS28 (r = 0.4; p = 0.04). As for advanced RA, 78 (80.4%) patients were high-positive for anti-CCP, and 70 (79.5%) were high-positive for anti-MCV. There was a positive correlation between anti-MCV concentration and SDAI (r = 0.4; p = 0.02), as well as CDAI (r = 0.4; p = 0.02). No significant correlations were found between the anti-CCP levels and activity indices, anti-CCP and acute-phase parameters in both early and advanced RA groups. Higher total Sharp scores (96.5 (65.0-122.0)) were found in pts highl-positive for anti-MCV (n = 79), compared to low-positive/negative (n = 27) patients (57.0 (31.0-88.0); p < 0.05). Anti-MCV levels dropped significantly in pts on rituximab and tocilizumab therapy at weeks 12 and 24 after initiation of treatment, while high anti-CCP concentration persisted throughout the treatment. Anti-MCV levels correlated with inflammatory activity and development of bone destruction and decreased in pts on treatment. Anti-CCP was less responsive and showed minor changes during treatment; therefore, its thorough monitoring was not feasible.

In Contrast to Anti-CCP, MMP-Degraded and Citrullinated Vimentin (VICM) Is Both a Diagnostic and a Treatment Response Biomarker

Protein citrullination and degradation by matrix metalloproteinases (MMP) plays a central role in the pathology of rheumatoid arthritis (RA). Autoantibodies are known to target citrullinated vimentin. The aim of this study was to investigate the relationship between the blood levels of MMP-degraded and citrullinated vimentin (VICM), as compared with the levels of MMP-degraded and non-citrullinated vimentin (VIM), and the standard anti-CCP biomarker in RA patients undergoing treatment. Thus, VIM, VICM and anti-CCP were quantified by ELISA in serum samples from baseline and week 8 of patients (n = 257) with RA, treated with either tocilizumab (8 mg/kg), methotrexate (7.5−15 mg/kg) or a placebo and compared with a reference cohort (n = 64). The three biomarkers were elevated in RA serum compared with the reference cohort: medians were 1.7 vs. 0.8 ng/mL (p < 0.05) for VIM; 7.5 vs. 0.7 ng/mL (p < 0.0001) for VICM; 57 vs. 4 RU/mL (p < 0.001) for anti-CCP. VICM was decreased in response to tocilizumab (2.9-fold, p < 0.0001) and to methotrexate (1.5-fold, p < 0.05) compared with the placebo, while anti-CCP was not. Serum VIM was also modulated by both drugs, although to a lesser degree. A high baseline level of VICM was predictive of a low disease activity response at week 8. In conclusion, VICM can differentiate between RA and healthy donors in a similar manner to anti-CCP; furthermore, VICM is also a pharmacodynamic marker.

Determining in which pre-arthritis stage HLA-shared epitope alleles and smoking exert their effect on the development of rheumatoid arthritis

OBJECTIVES

The human leukocyte antigen-shared epitope (HLA-SE) alleles and smoking are the most prominent genetic and environmental risk factors for rheumatoid arthritis (RA). However, at which pre-arthritis stage (asymptomatic/symptomatic) they exert their effect is unknown. We aimed to determine whether HLA-SE and smoking are involved in the onset of autoantibody positivity, symptoms (clinically suspect arthralgia (CSA)) and/or progression to clinical arthritis.

METHODS

We performed meta-analyses on results from the literature on associations of HLA-SE and smoking with anti-citrullinated protein antibodies (ACPAs) in the asymptomatic population. Next, we studied associations of HLA-SE and smoking with autoantibody positivity at CSA onset and with progression to clinical inflammatory arthritis (IA) during follow-up. Associations in ACPA-positive patients with CSA were validated in meta-analyses with other arthralgia cohorts. Analyses were repeated for rheumatoid factor (RF), anti-carbamylated protein antibodies (anti-CarP) and anti-acetylated protein antibodies (AAPA).

RESULTS

Meta-analyses showed that HLA-SE is not associated with ACPA positivity in the asymptomatic population (OR 1.06 (95% CI:0.69 to 1.64)), whereas smoking was associated (OR 1.37 (95% CI: 1.15 to 1.63)). At CSA onset, both HLA-SE and smoking associated with ACPA positivity (OR 2.08 (95% CI: 1.24 to 3.49), OR 2.41 (95% CI: 1.31 to 4.43)). During follow-up, HLA-SE associated with IA development (HR 1.86 (95% CI: 1.23 to 2.82)), in contrast to smoking. This was confirmed in meta-analyses in ACPA-positive arthralgia (HR 1.52 (95% CI: 1.08 to 2.15)). HLA-SE and smoking were not associated with RF, anti-CarP or AAPA-positivity at CSA onset. Longitudinally, AAPA associated with IA development independent from ACPA and RF (HR 1.79 (95% CI: 1.02 to 3.16)), anti-CarP did not.

CONCLUSIONS

HLA-SE and smoking act at different stages: smoking confers risk for ACPA and symptom development, whereas HLA-SE mediates symptom and IA development. These data enhance the understanding of the timing of the key risk factors in the development of RA.

Objective and noninvasive biochemical markers in rheumatoid arthritis: where are we and where are we going?

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune disease that affects approximately 1% of the adult population. RA is multi-factorial, and as such our understanding of the molecular pathways involved in the disease is currently limited. An increasing number of studies have suggested that several molecular phenotypes (i.e. endotypes) of RA exist, and that different endotypes respond differently to various treatments. Biochemical markers may be an attractive means for achieving precision medicine, as they are objective and easily obtainable.

AREAS COVERED

We searched recent publications on biochemical markers in RA as either diagnostic or prognostic markers, or as markers of disease activity. Here, we provide a narrative overview of different classes of markers, such as autoantibodies, citrulline products, markers of tissue turnover and cytokines, that have been tested in clinical cohorts or trials including RA patients.

EXPERT OPINION

Although many biochemical markers have been identified and tested, few are currently being used in clinical practice. As more treatment options are becoming available, the need for precision medicine tools that can aid physicians and patients in choosing the right treatment is growing.

Marham-Mafasel decrease joint inflammation and IL-1β gene expression in rheumatoid arthritis animal model

Background

Rheumatoid arthritis (RA) is a systemic chronic disease with synovial membrane, tendon and articular tissue inflammation. Current treatments of RA have many side effects and are quite expensive. Today, new treatments procedures and inexpensive herbal drugs are developed. Marham‐Mafasel is mainly made out of two traditional herbs (Arnebia euchroma and Martricaria chamomilla).

Objective

In this study, for the first time, the impact of Marham‐Mafasel on joint inflammation, histopathological changes and IL‐1β gene expression was evaluated in RA animal model.

Methods

The RA was induced by a single s.c. injection of 0.1 ml Freund's complete adjuvant into the left hind footpad. In continuous, 15 RA male Wistar rats were used in three groups: I: Control; II: Treatment I (Piroxicam) and III: Treatment II (Marham‐Mafasel). The volume of the hind paw was measured every day from 0 to 19 using water changed volume approach. The inflammation in the joint was evaluated using histopathology assay and gene expression of IL‐1β was evaluated with use of Real‐Time PCR.

Results

Hind paw swelling of Marham‐Mafasel at days 10th and 19th was reduced compared with the control group (p < 0.05). There was no statistically difference in histological degrading and changes index in three groups (p ≥ 0.05). Relative expression of IL‐1β in Marham‐Mafasel group was significantly decreased compared with other groups.

Conclusion

The co‐administration of M. Chamomile and A. euchroma, called Marham‐Mafasel, decreases IL‐1β gene expression that leads to a reduction in inflammation in rheumatoid arthritis (RA) animal model.

Rheumatoid Factor: A Novel Determiner in Cancer History

Simple Summary

Rheumatoid factors are autoantibodies that characterize different autoimmune diseases, in particular rheumatoid arthritis, but that can also be found in the sera of the general healthy population. They have been mainly studied in the context of autoimmune diseases, but some evidence have suggested an association between their presence and the predisposition to develop cancer as well as a facilitation of cancer growth and progression in oncologic patients. In this review, for the first time we thus analyze and discuss the possible roles that these autoantibodies can assume in tumor history, from determiners of a heightened susceptibility of developing cancer to drivers of a reduced response to immunotherapies.

Abstract

The possible interplay between autoimmunity and cancer is a topic that still needs to be deeply explored. Rheumatoid factors are autoantibodies that are able to bind the constant regions (Fc) of immunoglobulins class G (IgGs). In physiological conditions, their production is a transient event aimed at contributing to the elimination of pathogens as well as limiting a redundant immune response by facilitating the clearance of antibodies and immune complexes. Their production can become persistent in case of different chronic infections or diseases, being for instance a fundamental marker for the diagnosis and prognosis of rheumatoid arthritis. Their presence is also associated with aging. Some studies highlighted how elevated levels of rheumatoid factors (RFs) in the blood of patients are correlated with an increased cancer risk, tumor recurrence, and load and with a reduced response to anti-tumor immunotherapies. In line with their physiological roles, RFs showed in different works the ability to impair in vitro anti-cancer immune responses and effector functions, suggesting their potential immunosuppressive activity in the context of tumor immunity. Thus, the aim of this review is to investigate the emerging role of RFs as determiners of cancer faith.

Inhibitory activity of FOXP3+ regulatory T cells reveals high specificity for displaying immune tolerance in remission state rheumatoid arthritis

Immune regulation status may indicate immunological remission in rheumatoid arthritis (RA). This cross-sectional study aimed to determine the Regulatory T cell (Treg) properties, together with 14 plasma cytokines levels between active RA and clinical remission patients. Peripheral blood (PB) Foxp3+ Treg was collected from RA patients for determination of Treg inhibitory activity using a co-culture system. Other PB T cell types and plasma cytokines were determined by flow-cytometry. The Treg results were analyzed according to the disease activity score-28 (DAS28). Then sensitivity and specificity were calculated for the indication of the remission status. The number and inhibitory activity of Treg are higher in the clinical remission as compared to the active RA (p value < 0.0001). Also, Treg: CD4+CD25+CD127+ cell ratio demonstrates the similar result (p value < 0.05). Treg inhibitory activity is inversely correlated with the DAS28. Specificity and positive likelihood ratio of inhibitory activity for indicating remission status are 92.31% (95% CI 63.97-99.81) and 11.14 (95% CI 1.67-74.14), respectively. Treg inhibitory activity is a promising prognostic marker and probably represents the immunological remission status in RA.

A comprehensive review on miR-146a molecular mechanisms in a wide spectrum of immune and non-immune inflammatory diseases

MicroRNAs (miRNAs) are single-strand endogenous and non-coding RNA molecules with a length of about 22 nucleotides, which regulate genes expression, through modulating the translation and stability of their target mRNAs. miR-146a is one of the most studied miRNAs, due to its central role in immune system homeostasis and control of the innate and acquired immune responses. Accordingly, abnormal expression or function of miR-146a results in the incidence and progression of immune and non-immune inflammatory diseases. Its deregulated expression pattern and inefficient function have been reported in a wide spectrum of these illnesses. Based on the existing evidence, this miRNA qualifies as an ideal biomarker for diagnosis, prognosis, and activity evaluation of immune and non-immune inflammatory disorders. Moreover, much attention has recently been paid to therapeutic potential of miR-146a and several researchers have assessed the effects of different drugs on expression and function of this miRNA at diverse experimental, animal, besides human levels, reporting motivating results in the treatment of the diseases. Here, in this comprehensive review, we provide an overview of miR-146a role in the pathogenesis and progression of several immune and non-immune inflammatory diseases such as Rheumatoid arthritis, Systemic lupus erythematosus, Inflammatory bowel disease, Multiple sclerosis, Psoriasis, Graves' disease, Atherosclerosis, Hepatitis, Chronic obstructive pulmonary disease, etc., discuss about its eligibility for being a desirable biomarker for these disorders, and also highlight its therapeutic potential. Understanding these mechanisms underlies the selecting and designing the proper therapeutic targets and medications, which eventually facilitate the treatment process.

Defining remission in rheumatoid arthritis: does it matter to the patient? A comparison of multi-dimensional remission criteria and patient reported outcomes

OBJECTIVES

In a cross-sectional study, we evaluated the prevalence of 'multi-dimensional remission' (MDR) and its component parameters, assessed using objective measures in a cohort of RA patients in treatment-induced DAS28-remission, and their relationship with patient-reported outcome measures. We sought to confirm the feasibility and face validity of the MDR construct, providing a platform for future longitudinal studies in which its clinical utility might be further established.

METHODS

605 patients were selected from an inflammatory arthritis register using DAS28(CRP)<2.6. Demographic, clinical and patients reported outcomes (PRO) data were collected. Ultrasound power doppler synovitis (n = 364) and T-cell subsets (n = 297) were also measured. Remission using clinical parameters was defined as: tender and swollen joint count (TJC/SJC) and CRP all ⩽1; ultrasound remission: total power doppler = 0 and T cell remission: positive normalized naïve T-cell frequency. MDR was defined as the achievement of all three dimensions.

RESULTS

Overall, only 53% (321/605) of the patients achieved clinical parameters, failures being mainly due to raised CRP (52%), TJC (28)>1 (37%) or SJC (28)>1 (16%). 211/364 (58%) of patients achieved ultrasound remission and 193/297 (65%) patients showed T-cell remission. Complete data were available for 231 patients. MDR was observed in only 35% and was associated with the best (lower) PRO scores (all P ⩽ 0.05 vs non-MDR) when compared with the other definitions of remission assessed. The MDR rate was similar in early and established RA patients on b-DMARDs; however, it was lower in established RA patients who received multiple cs-DMARDs (P = 0.011).

CONCLUSIONS

In this study, MDR, which may represent a state closer to normality, was found to occur in about a third of DAS28-remission patients and was associated with better patient-reported outcome measures. MDR could be a novel optimal treatment target, notably from a patient's perspective. The relevance of these findings needs further assessment.

Timing of Elevations of Autoantibody Isotypes Prior to Diagnosis of Rheumatoid Arthritis

OBJECTIVE

To evaluate patterns of elevations of isotypes of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs) pre-rheumatoid arthritis (RA) diagnosis and post-RA diagnosis.

METHODS

Using the Department of Defense Serum Repository we identified 214 RA cases and 210 matched controls. Up to 3 pre-RA diagnosis and 1 post-RA diagnosis serum samples per subject were tested for RF and for IgA, IgG, and IgM ACPAs. The timing and trajectories of elevations of autoantibodies were evaluated.

RESULTS

Autoantibody levels were elevated in cases versus controls a mean of 17.9 years before RA diagnosis for IgG ACPA, 14.2 years for IgA-RF, 7.2 years for IgM-RF, 6.2 years for IgA ACPA, and 5.0 years for both IgM ACPA and IgG-RF (P < 0.01 for all comparisons). There were similar relationships for positive or negative autoantibody status, with cases first showing positivity for IgG ACPA 1.9 years pre-RA and for IgA-RF 1.7 years pre-RA, followed by the other isotypes. Only IgA ACPA positivity was significantly increased in post-RA diagnosis samples (19% 0-2 years pre-RA versus 39% >2 years post-RA diagnosis; P = 0.04). All autoantibody levels demonstrated an early initial elevation, a period of stability, then an increase immediately before RA diagnosis. A pre-RA endotype of early elevation of autoantibodies was associated with increased use of biologic therapy, and a higher prevalence of sicca symptoms and lung disease post-RA diagnosis.

CONCLUSION

Differences in patterns of elevations of autoantibody isotypes have implications for understanding the pathophysiology of RA development. These include understanding what factors drive initial autoantibody elevations compared to what factors (including mucosal) drive later increases in autoantibody levels and a transition to clinically apparent RA, and how pre-RA endotypes may influence post-RA diagnosis phenotypes.

Detection of anti-citrullinated protein antibody (ACPA) in saliva for rheumatoid arthritis using DBA mice infected with Porphyromonas gingivalis

OBJECTIVE

The anti-citrullinated protein antibody (ACPA), an autoantibody of rheumatoid arthritis (RA), is very specific in the diagnosis of RA and has been detected in early cases and several years before the onset of the disease. In this study, we focused on ACPA and examined whether it could be detected in saliva whether it is associated with periodontal disease.

DESIGN

Porphyromonas gingivalis (Pg) or Escherichia coli (Ec) was administered into the oral cavity of DBA/1JJmsSlc mice. The arthritis index was measured in foot bones, and collected saliva and serum. The amount of ACPA in serum and saliva was measured using ELISA, and antibodies in serum, saliva, and foot bones were detected and analysed by western blotting.

RESULT

Histopathological analysis of foot bones of the Pg/RA group detected greater inflammatory cell infiltration than in the RA group, and bone resorption was evident. Furthermore, ELISA results show that the amount of ACPA in serum was significantly higher in the Pg/RA group (P < 0.05), with a tendency to also increase in the saliva. In addition, western blotting results show a 55 kDa citrullinated protein in the serum and saliva of the RA and Pg/RA groups.

CONCLUSIONS

We conclude that Pg infection increases ACPA in the serum and is reflected in the saliva, and may be involved in the inflammatory progression of RA.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

An epidemiological analysis of osteoporotic characteristics in patients affected with rheumatoid arthritis in Kazakhstan

PURPOSE

We aimed to assess which of the major risk factors associated with rheumatoid arthritis (RA) severity are also associated with osteoporosis-related phenotypes (OP-RP) in the native population of Kazakhstan.

METHODS

Four hundred six RA patients (90.6% females) with 397 controls-unaffected first-degree relatives were recruited. Biochemical factors were recorded, and OP-RP were assessed using QCT scans and ultrasound densitometry (US) of the forearm to estimate cortical indices (CI), spongial bone mineral density (BMD_SPN), and US_T-scores.

RESULTS

In the RA affected female population, ~ 80% suffered from osteopenia or osteoporosis. All OP-RP were negatively correlated with age and female's sex, as expected, and thus accordingly adjusted, resulting in consistent, significantly [p = 0.016 (CI), p < 0.0001 (both BMD_SPN and US_T-scores)] lower OP-RP estimates in affected females. Using multiple regression analysis for OP-RP manifestations, only age and disease duration appeared consistently associated with all three studied phenotypes, while menopause status or years following the onset of menopause were also significant for BMD_SPN and US_T-scores. However, when disease duration was examined, we found that it was significantly dependent on morning stiffness, ESR, total cholesterol levels, weight, and menopause status, which explains 38.6% of the disease duration.

CONCLUSIONS

Approximately 80% of female RA patients suffer from osteoporosis or osteopenia in the study group, which appears from a young age. RA disease duration is the major risk factor for OP-RP deterioration, especially as assessed by BMD_SPNG, and US_T-scores. As a result, all OP-RP demonstrate significantly lower levels in comparison to sex- and age-matched unaffected individuals.

Conversion to seronegative status after abatacept treatment in patients with early and poor prognostic rheumatoid arthritis is associated with better radiographic outcomes and sustained remission: post hoc analysis of the AGREE study

Objective

To evaluate the effects of the T-cell costimulation blocker abatacept on anti-citrullinated protein antibodies (ACPA) and rheumatoid factor (RF) in early rheumatoid arthritis (RA), and associations between changes in serological status and clinical response.

Methods

Post hoc analysis of the phase III AGREE study in methotrexate (MTX)-naïve patients with early RA and poor prognostic factors. Patients were randomised to abatacept (~10 mg/kg intravenously according to weight range) or placebo, plus MTX over 12 months followed by open-label abatacept plus MTX for 12 months. Autoantibody titres were determined by ELISA at baseline and months 6 and 12 (double-blind phase). Conversion to seronegative status and its association with clinical response were assessed at months 6 and 12.

Results

Abatacept plus MTX was associated with a greater decrease in ACPA (but not RF) titres and higher rates of both ACPA and RF conversion to seronegative status versus MTX alone. More patients converting to ACPA seronegative status receiving abatacept plus MTX achieved remission according to Disease Activity Score in 28 joints (C-reactive protein) or Clinical Disease Activity Index than patients who remained ACPA seropositive. Patients who converted to ACPA seronegative status treated with abatacept plus MTX had a greater probability of achieving sustained remission and less radiographic progression than MTX alone or patients who remained ACPA seropositive (either treatment).

Conclusions

Treatment with abatacept plus MTX was more likely to induce conversion to ACPA/RF seronegative status in patients with early, erosive RA. Conversion to ACPA seronegative status was associated with better clinical and radiographic outcomes.

Trial registration number

NCT00122382

Cost-Effectiveness Analysis of Abatacept Compared with Adalimumab on Background Methotrexate in Biologic-Naive Adult Patients with Rheumatoid Arthritis and Poor Prognosis

OBJECTIVES

To assess cost effectiveness of abatacept versus adalimumab, each administered with methotrexate, in treating patients with rheumatoid arthritis (RA) stratified according to baseline anticitrullinated protein antibody (ACPA) levels (marker of poor prognosis in RA).

METHODS

A payer-perspective cost-effectiveness model simulated disease progression in patients with RA who had previously failed conventional disease-modifying antirheumatic drugs and were starting biologic therapy. Patients commenced treatment with abatacept or adalimumab plus methotrexate and were evaluated after 6 months. Therapy continuation was based on the European League Against Rheumatism treatment response; disease progression was based on the Health Assessment Questionnaire Disability Index score. These score changes were used to estimate health state utilities and direct medical costs. Quality-adjusted life-years (QALYs) and incremental cost per QALY gained were calculated by baseline ACPA groups (Q1, 28-234 AU/ml; Q2, 235-609 AU/ml; Q3, 613-1045 AU/ml; and Q4, 1060-4894 AU/ml). Scenario analysis and one-way and probabilistic sensitivity analyses were used to evaluate robustness of model assumptions.

RESULTS

Abatacept resulted in QALY gain versus adalimumab in ACPA Q1, Q3, and Q4; between-treatment difference (difference: Q1, -0.115 Q2, -0.009 Q3, 0.045; and Q4, 0.279). Total lifetime discounted cost was higher for abatacept versus adalimumab in most quartiles (Q2, £77,612 vs. £77,546; Q3, £74,441 vs. £73,263; and Q4, £78,428 vs. £76,696) because of longer time on treatment. Incremental cost per QALY for abatacept (vs. adalimumab) was the lowest in the high ACPA titer group (Q4, £6200/QALY), followed by the next lowest titer group (Q3, £26,272/QALY).

CONCLUSIONS

Abatacept is a cost effective alternative to adalimumab in patients with RA with high ACPA levels.

Rheumatoid factor is correlated with disease activity and inflammatory markers in antineutrophil cytoplasmic antibody-associated vasculitis

BACKGROUND

Some patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) also have positivity of rheumatoid factor (RF). However, the clinical significance of this occurrence remains unknown in AAV patients. The aim of this study was to clarify an association between the presence of RF and clinical features in patients with AAV.

RESULTS

Forty-seven patients diagnosed with AAV who were not complicated with RA were enrolled in this study. We compared clinical manifestations of AAV between an RF-positive subset (n = 29) and an RF-negative subset (n = 18). The Birmingham Vasculitis Activity Score (BVAS) was higher (P = 0.026) in the RF-positive subset than in the RF-negative subset. The levels of CRP and ESR were higher in the RF-positive patients (P = 0.020 and P = 0.007, respectively) compared to the RF-negative subset. IgM-RF titers were significantly correlated with the BVAS (r = 0.50, P = 0.0004). In addition, the IgM-RF titers had significant correlations with the levels of CRP (r = 0.41, P = 0.004), ESR (r = 0.39, P = 0.016), IgM (r = 0.36, P = 0.016) and IgG (r = 0.37, P = 0.015). The frequency of commencement of dialysis therapy, usage of mechanical ventilation and mortality were higher in the RF-positive subset than in the RF-negative subset.

CONCLUSIONS

In patients with AAV, RF titers were significantly correlated with disease activity and the levels of inflammatory markers. The presence of RF could be a poor prognostic factor in patients with AAV.

Only rheumatoid factor-positive subset of anti-citrullinated peptide/protein antibody-negative rheumatoid arthritis may seroconvert to anti-citrullinated peptide/protein antibody-positive

AIM

Anti-citrullinated peptide/protein antibody (ACPA) has been reported to occur in about 60% of patients with early rheumatoid arthritis (RA), and about 80% in patients with established RA. While ACPA seroconversion is possible, previous reports have shown that it rarely occurs. We retrospectively determined the proportion of patients who underwent ACPA seroconversion and described the clinical characteristics of these cases.

METHODS

ACPA-negative RA patients who had undergone ACPA assessment more than once with an interval of 3 months or longer were investigated for ACPA seroconversion. The clinical characteristics of seroconverted patients were assessed.

RESULTS

In 149 ACPA-negative RA patients, only eight patients (5.4%) converted to ACPA-positive during follow-up. We found that all eight of the seroconverted cases were positive for rheumatoid factor (RF) and showed bone erosions by X-ray. Of 56 ACPA-negative RF-positive RA patients, 14.3% of them seroconverted to ACPA-positive. None of the ACPA-negative RF-negative RA patients seroconverted to ACPA-positive.

CONCLUSION

The proportion of total RA patients who experienced seroconversion from ACPA-negative to ACPA-positive was 5.4%. When ACPA-negative RA patients were subdivided into RF-negative and RF-positive subsets, only the RF-positive subset seroconverted to ACPA-positive. These results imply that RF-negative and RF-positive patients are distinct subsets within ACPA-negative RA patients.

How does established rheumatoid arthritis develop, and are there possibilities for prevention?

Established rheumatoid arthritis (RA) is a chronic state with more or less joint damage and inflammation, which persists after a phase of early arthritis. Autoimmunity is the main determinant of persistence. Although the autoimmune response is already fully developed in the phase of early arthritis, targeted treatment within the first months produces better results than delayed treatment. Prevention of established RA currently depends on the success of remission-targeted treatment of early disease. Early recognition is aided by the new criteria for RA. Further improvement may be possible by even earlier recognition and treatment in the at-risk phase. This requires the improvement of prediction models and strategies, and more intervention studies. Such interventions should also be directed at modifiable risk factors such as smoking and obesity. The incidence of RA has declined for decades in parallel with the decrease of smoking rates; however, a recent increase has occurred that is associated with obesity.

Rheumatoid factor, not antibodies against citrullinated proteins, is associated with baseline disease activity in rheumatoid arthritis clinical trials

INTRODUCTION

Although the prognostic value of rheumatoid factor (RF) and autoantibodies against citrullinated proteins (ACPAs) in patients with rheumatoid arthritis (RA) is well established, their association with RA disease activity remains unclear. Here, we investigate this association in a large study using data from clinical trials.

METHODS

We used baseline data from four recent randomized controlled clinical trials of RA. We investigated individual and composite measures of disease activity. The relationship of RF and ACPAs with these measures was investigated by using stratified analysis (comparing four groups of patients according to the presence or absence of RF and ACPAs) and matched analysis (disease activity levels compared between patients negative and patients highly positive for one autoantibody who were matched for levels of the other autoantibody as well as for age, gender, and duration of RA).

RESULTS

A total of 2118 patients were analysed in the different cohorts. In the stratified analysis, RF(+) patients, regardless of ACPA status, had the highest levels of disease activity, whereas ACPA(+) patients had disease activity that was similar to or lower than that of ACPA(-) patients, both in the presence and in the absence of RF. When matched for ACPA levels, patients with highly positive RF had significantly higher disease activity for all composite indices compared with patients who were RF(-) (P = 0.0067), whereas ACPA-highly-positive and ACPA-negative patients matched for RF levels had similar disease activity, again even with the tendency toward lower disease activity for ACPA(+) patients (P = 0.054).

CONCLUSION

The data presented suggest that the presence of RF has a clear association with higher levels of disease activity but that the presence of ACPAs has not and even appears to be associated with lower disease activity.

Antibodies to IgG4 hinge can be found in rheumatoid arthritis patients during all stages of disease and may exacerbate chronic antibody-mediated inflammation

OBJECTIVE

In rheumatoid arthritis (RA), autoantibodies such as anti-citrullinated protein antibodies (ACPAs) develop in response to neoepitopes that are formed under conditions of chronic inflammation. These autoantibodies may subsequently be fragmented by inflammation-associated proteases, leading to the formation of F(ab')2 fragments. The hinge of F(ab')2 fragments can serve as a neoepitope, and so-called antihinge antibodies (AHAs) can be found in RA patients, which might modulate the function of (fragmented) autoantibodies. We undertook this study to investigate the presence and specificities of AHAs in different stages of RA and to study their function.

METHODS

The presence of AHAs was assessed by radioimmunoassay in healthy controls, blood donors who later developed RA, patients with arthralgia, patients with early RA, and patients with established RA. Specificity of the AHAs was analyzed with inhibition assays, and complement-activating ability was studied with a C4b deposition assay.

RESULTS

Antibodies to IgG1 hinge, IgG2 hinge, and IgG4 hinge were detected in patients with established RA, with anti-IgG4 hinge antibodies being most specific (appearing in 1% of healthy controls, 3.8% of blood donors who later developed RA, 13% of arthralgia patients, 19% of early RA patients, and 16% of established RA patients). Anti-IgG4 hinge antibodies were subclass specific and were able to restore C4b deposition by IgG4 F(ab')2 fragments. In patients with arthralgia and patients with early RA, anti-IgG4 hinge antibodies were associated with rheumatoid factors and ACPAs.

CONCLUSION

Anti-IgG4 hinge antibodies are present in RA patients and have low sensitivity but high specificity for RA. Since a significant proportion of ACPAs can be of the IgG4 subclass, the formation of anti-IgG4 hinge antibodies may represent one mechanism of ACPA-mediated inflammation.

Big data and clinicians: a review on the state of the science

BACKGROUND

In the past few decades, medically related data collection saw a huge increase, referred to as big data. These huge datasets bring challenges in storage, processing, and analysis. In clinical medicine, big data is expected to play an important role in identifying causality of patient symptoms, in predicting hazards of disease incidence or reoccurrence, and in improving primary-care quality.

OBJECTIVE

The objective of this review was to provide an overview of the features of clinical big data, describe a few commonly employed computational algorithms, statistical methods, and software toolkits for data manipulation and analysis, and discuss the challenges and limitations in this realm.

METHODS

We conducted a literature review to identify studies on big data in medicine, especially clinical medicine. We used different combinations of keywords to search PubMed, Science Direct, Web of Knowledge, and Google Scholar for literature of interest from the past 10 years.

RESULTS

This paper reviewed studies that analyzed clinical big data and discussed issues related to storage and analysis of this type of data.

CONCLUSIONS

Big data is becoming a common feature of biological and clinical studies. Researchers who use clinical big data face multiple challenges, and the data itself has limitations. It is imperative that methodologies for data analysis keep pace with our ability to collect and store data.

Rheumatoid factors: clinical applications

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

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.

The role of B lymphocytes in the progression from autoimmunity to autoimmune disease

Autoimmunity, defined as the presence of autoreactive T and/or B lymphocytes in the periphery, is a frequent and probably even physiological condition. It is mainly caused by the fact that the central tolerance mechanisms, which are responsible for counter-selection of autoreactive lymphocytes, are not perfect and thus a limited number of these autoreactive cells can mature and enter the periphery. Nonetheless, autoreactive cells do not lead automatically to autoimmune disease as evidenced by a multitude of experimental and human data sets. Interestingly, the progression from autoimmunity to autoimmune disease is not only determined by the degree of central tolerance leakage and thus the amount of autoreactive lymphocytes in the periphery, but also by peripheral mechanism of activation and control of the autoreactive cells. In this review, we discuss the contribution of peripheral B lymphocytes in this process, ranging from activation of T cells and epitope spreading to control of the autoimmune process by regulatory mechanisms. We also discuss the parallels with the role of B cells in the induction and control of alloimmunity in the context of organ transplantation, as more precise knowledge of the pathogenic antigens and time of initiation of the immune response in allo- versus auto-immunity allows better dissection of the exact role of B cells. Since peripheral mechanisms may be easier to modulate than central tolerance, a more thorough understanding of the role of peripheral B cells in the progression from autoimmunity to autoimmune disease may open new avenues for treatment and prevention of autoimmune disorders.

Long-term stability of anti-cyclic citrullinated peptide antibody status in patients with early inflammatory polyarthritis

Introduction

The utility of reassessing anti-cyclic citrullinated peptide (anti-CCP) antibody status later in disease in patients presenting with early undifferentiated inflammatory polyarthritis, particularly in those who test negative for both anti-CCP and rheumatoid factor (RF) at baseline, remains unclear. We aimed therefore to determine the stability of CCP antibody status over time and the prognostic utility of repeated testing in subjects with early inflammatory polyarthritis (IP).

Methods

Anti-CCP and RF were measured at baseline and 5 years in 640 IP patients from the Norfolk Arthritis Register, a primary care-based inception cohort. The relation between change in anti-CCP status/titer and the presence of radiologic erosions, the extent of the Larsen score, and Health Assessment Questionnaire (HAQ) score by 5 years was investigated.

Results

With a cut-off of 5 U/ml, 28% subjects tested positive for anti-CCP antibodies, 29% for RF, and 21% for both at baseline. Nine (2%) anti-CCP-negative patients seroconverted to positive, and nine (4.6%) anti-CCP-positive individuals became negative between baseline and 5 years. In contrast, RF status changed in 17% of subjects. However, change in RF status was strongly linked to baseline anti-CCP status and was not independently associated with outcome. Ever positivity for anti-CCP antibodies by 5 years did not improve prediction of radiographic damage compared with baseline status alone (accuracy, 75% versus 74%). A higher baseline anti-CCP titer (but not change in anti-CCP titer) predicted worse radiologic damage at 5 years (P < 0.0001), even at levels below the cut-off for anti-CCP positivity. Thus, a titer of 2 to 5 U/ml was strongly associated with erosions by 5 years (odds ratio, 3.6 (1.5 to 8.3); P = 0.003).

Conclusions

Repeated testing of anti-CCP antibodies or RF in patients with IP does not improve prognostic value and should not be recommended in routine clinical practice.

Changes in proliferation kinetics of T cells: a new predictive cellular biomarkers for early rheumatoid arthritis?

OBJECTIVE

It has been demonstrated that early treatment of rheumatoid arthritis (RA) patients prevents further joint damage and disability, but biomarkers enabling early RA to be distinguished within the undifferentiated arthritis (UA) cohort are still being sought.

PURPOSE

The aim of the research was to study the pathomechanism of initiation and progression of UA→RA and to find such new predictive biomarkers on the basis of functional studies of the immune system.

METHODS

55 patients with UA were enrolled into the study and followed up for 2 years. The dynamic parameters of proliferation of the peripheral blood CD4+ T cells were recorded at the UA stage. During the follow-up study, standard diagnostic procedures were performed to make the final diagnosis. Comparison of the CD4+ T cell proliferation parameters in the UA-RA and UA-non-RA patients was conducted after the final diagnosis was established.

RESULTS

Our studies showed that the G0-G1 transition time, the cell cycle duration, the number of cell divisions per dividing CD4+ cells and the percentage of dividing CD4+ T cells differed significantly between UA-RA and UA-non-RA patients. Moreover, these proliferation parameters achieved higher specificity and sensitivity in the detection of early RA within UA patients compared to the routine serological tests available.

CONCLUSION

The proliferation parameters of CD4+ T cells reflect central pathophysiological changes in RA and can be used as new biomarkers for early RA diagnosis, which would enable the international rheumatology recommendation to be achieved concerning the early diagnosis and treatment of RA patients.

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.

Levels of anti-citrullinated protein antibodies and IgM rheumatoid factor are not associated with outcome in early arthritis patients: a cohort study

Introduction

To investigate whether baseline levels of anti-citrullinated protein antibody (ACPA) or IgM rheumatoid factor (IgM-RF) and changes in the year thereafter are associated with disease activity, functional and radiographic outcome in early arthritis patients, and provide additional information over baseline autoantibody status.

Methods

In 545 early arthritis patients ACPA and IgM-RF levels, disease activity (DAS28), the Health Assessment Questionnaire (HAQ) and Sharp/Van der Heijde Score (SHS) were assessed annually. Baseline status, levels and first-year changes of the autoantibodies were associated with these measures at the two-year follow-up and sub-analysed according to autoantibody status.

Results

The mean age was 52.7 years, 69% was female, at baseline 56% was ACPA positive, 47% IgM-RF positive. At the two-year follow-up the mean DAS28 was 2.88, and the median HAQ and SHS were 0.38 and 1, respectively. At one year, ACPA and IgM-RF levels had decreased by 31% and 56%, respectively. A switch from negative to positive occurred in 2% for ACPA and 3% for IgM-RF. Positive ACPA and RF status were both associated with SHS at two years (P < 0.001), but baseline levels only showed a minor correlation of ACPA with DAS28 and HAQ at two years. Level changes were not associated with the outcome parameters.

Conclusions

Baseline levels and first-year changes of ACPA and IgM-RF are hardly associated with outcome after two years. Seroconversion seldom occurs. Therefore, it does not appear useful to repeat ACPA or IgM-RF measurements.

Clinical approaches to early inflammatory arthritis

Several advances have been made in the understanding of the pathogenesis, as well as in the clinical evaluation and treatment, of early inflammatory arthritis. The presence of anti-citrullinated protein antibodies (ACPAs) has emerged as a major new biomarker for use in clinical practice. The presence of ACPAs can be used to divide patients with early arthritis into subsets that are phenotypically similar but have varying pathogenetic and prognostic features. Although the detection of ACPAs is a major development in the diagnosis and prognosis of rheumatoid arthritis (RA), prediction of the outcome of arthritis at the individual level can still be much improved. For patients diagnosed with RA, and who have active polyarthritis, treatment is not dependent on the assessment of prognostic factors, as these patients are best treated with combination therapy; over 40% of these patients achieve remission with such treatment. In patients who present with oligoarthritis, however, management should be based on the assessment of prognostic factors. The success of early treatment of inflammatory arthritis and the recognition of a measurable preclinical phase of RA offer hope that treating the disease before it becomes clinically active might be possible.

Anticitrullinated protein/peptide antibodies and rheumatoid factors: two distinct autoantibody systems

In a previous issue of Arthritis Research and Therapy, Ursum and colleagues report the relative stabilities of anticitrullinated protein/peptide antibodies (ACPAs) and IgM rheumatoid factors during the course of rheumatoid arthritis and their differential correlation with markers of the acute-phase response. These findings add to a growing body of evidence highlighting the distinct nature of these two autoantibody systems and the role of ACPAs as a disease-specific marker of rheumatoid arthritis.