Diagnosis and prognosis of early rheumatoid arthritis, with special emphasis on laboratory analysis

A Monovalent Fab Affinity-Capture and Elution Bridging Immunoassay Overcomes Rheumatoid Factor Interference while Accurately Detecting Antidrug Antibodies

BACKGROUND

Rheumatoid factor (RF) consists of autoantibodies that bind the fragment crystallizable (Fc) region of human immunoglobulin G (IgG) and present in sera of rheumatoid arthritis (RA) patients. Immunoassays to detect antidrug antibodies (ADA) in RA patient samples may experience interference due to RF binding and crosslinking Fc regions of the capture and detection antibody reagents. To overcome this interference, a novel Fab affinity-capture and elution (ACE)-bridging immunoassay (Fab ACE-Bridge) was developed with monovalent-recombinant Fab to avoid RF interference.

METHODS

ACE and ACE-Bridge assays were developed to detect ADA against a therapeutic monoclonal antibody using samples from healthy donors, psoriasis patients, and RA patients. The performance of these assays was compared to a novel Fab ACE-Bridge assay, in which monoclonal antibody was replaced with monovalent Fab.

RESULTS

High screening signals in the ACE and ACE-Bridge assays were detected in RA patient samples but not in samples from healthy donors or psoriasis patients. The high screening signals in RA samples did not inhibit to the expected extent in the confirmatory assay, a consistent feature of false-positive screening results. Further investigation revealed RF as the interferent affecting assay performance. Modification of the ACE-Bridge assay by using monovalent Fab eliminated RF interference while allowing for sensitive and drug-tolerant detection of authentic ADA.

CONCLUSIONS

RF interfered significantly in traditional ACE and ACE-Bridge assays. Implementation of a novel monovalent Fab ACE-Bridge assay overcame RF interference. The use of monovalent Fab is recommended for immunogenicity assays when assessing ADA in RA patient samples.

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.

Targeted antibody therapy and relevant novel biomarkers for precision medicine for rheumatoid arthritis

Over the past two decades, the management of rheumatoid arthritis (RA) has progressed remarkably, encompassing the development of new diagnostic tools and efficacious biological agents, such as monoclonal antibodies against inflammatory cytokines and surface markers on immune cells. In addition to the significant efficacy of these biological agents, biomarkers for RA are under consideration for their potential to classify heterogeneous patients into several groups based on clinical and immunological phenotypes for the prediction of clinical course and prognosis and the facilitation of appropriate and precise treatment with the appropriate therapeutic monoclonal antibodies. Biomarkers, particularly those for the prediction and monitoring of the responses to therapeutic monoclonal antibodies for RA, are in demand, with many approaches examined in recent years. In this article, we have summarized the background research on biomarkers and introduced recent topics in the field that enable the possible clinical applications of biomarkers, especially those related to pathogenic cytokines, to guide the treatment of RA.

Circulating serum interleukin-6, serum chitinase-3-like protein-1, and plasma vascular endothelial growth factor are not predictive for remission and radiographic progression in patients with early rheumatoid arthritis: post-hoc explorative and validation studies based on the CIMESTRA and OPERA trials

OBJECTIVE

To investigate serum interleukin-6 (IL-6), serum chitinase-3-like protein-1 (YKL-40), and plasma vascular endothelial growth factor (VEGF) as measures of disease activity and predictors of clinical remission and radiographic progression in two early rheumatoid arthritis (RA) randomized controlled trials (RCTs).

METHOD

Treatment-naïve patients with early RA (< 6 months' duration) and active disease, participating in two investigator-initiated RCTs, were treated according to a predefined treat-to-target algorithm aiming at inflammatory control, using methotrexate (MTX) + cyclosporine versus MTX + placebo (CIMESTRA study, n = 150, 5 year follow-up) or MTX + adalimumab versus MTX + placebo (OPERA study, n = 180, 2 year follow-up). The 28-joint Disease Activity Score (DAS28) and conventional radiography [bilateral hands and feet at baseline, 2 years and 5 years (only CIMESTRA)] were obtained at baseline and during follow-up. Serum IL-6, serum YKL-40, and plasma VEGF were measured in baseline blood samples and during follow-up. Hypotheses regarding the biomarkers' relation with DAS28 and ability to predict clinical remission (DAS28 < 2.6) and radiographic progression (change in total Sharp van der Heijde score ≥ 2) were generated in CIMESTRA and validated in OPERA, by Spearman's correlation and logistic regression analyses.

RESULTS

Baseline IL-6, YKL-40, and VEGF correlated significantly with DAS28 in CIMESTRA (r = 0.50, r = 0.36, r = 0.36, respectively, all p < 0.01) and these results were confirmed in OPERA patients (r = 0.52, p < 0.01; r = 0.18, p = 0.01; r = 0.23, p = 0.002, respectively). None of the biomarkers (absolute values or change) was predictive of clinical remission or radiographic progression at 2 or 5 years in either study.

CONCLUSION

Serum IL-6, serum YKL-40, and plasma VEGF were significantly correlated with DAS28 at baseline, but did not have consistent predictive value for clinical remission or radiographic progression in two early RA RCTs.

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

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

Current and future trends in biomarker discovery and development of companion diagnostics for arthritis

Musculoskeletal diseases such as rheumatoid arthritis are complex multifactorial disorders that are chronic in nature and debilitating for patients. A number of drug families are available to clinicians to manage these disorders but few tests exist to target these to the most responsive patients. As a consequence, drug failure and switching to drugs with alternate modes of action is common. In parallel, a limited number of laboratory tests are available which measure biological indicators or 'biomarkers' of disease activity, autoimmune status, or joint damage. There is a growing awareness that assimilating the fields of drug selection and diagnostic tests into 'companion diagnostics' could greatly advance disease management and improve outcomes for patients. This review aims to highlight: the current applications of biomarkers in rheumatology with particular focus on companion diagnostics; developments in the fields of proteomics, genomics, microbiomics, imaging and bioinformatics and how integration of these technologies into clinical practice could support therapeutic decisions.

Predictive value of autoantibody testing for validating self-reported diagnoses of rheumatoid arthritis in the Women's Health Initiative

Rheumatoid arthritis (RA) research using large databases is limited by insufficient case validity. Of 161,808 postmenopausal women in the Women's Health Initiative, 15,691 (10.2%) reported having RA, far higher than the expected 1% population prevalence. Since chart review for confirmation of an RA diagnosis is impractical in large cohort studies, the current study (2009-2011) tested the ability of baseline serum measurements of rheumatoid factor and anti-cyclic citrullinated peptide antibodies, second-generation assay (anti-CCP2), to identify physician-validated RA among the chart-review study participants with self-reported RA (n = 286). Anti-CCP2 positivity had the highest positive predictive value (PPV) (80.0%), and rheumatoid factor positivity the lowest (44.6%). Together, use of disease-modifying antirheumatic drugs and anti-CCP2 positivity increased PPV to 100% but excluded all seronegative cases (approximately 15% of all RA cases). Case definitions inclusive of seronegative cases had PPVs between 59.6% and 63.6%. False-negative results were minimized in these test definitions, as evidenced by negative predictive values of approximately 90%. Serological measurements, particularly measurement of anti-CCP2, improved the test characteristics of RA case definitions in the Women's Health Initiative.

Relations of serum COMP to cardiovascular risk factors and endothelial function in patients with rheumatoid arthritis treated with methotrexate and TNF-α inhibitors

OBJECTIVE

To examine whether serum level of cartilage oligomeric matrix protein (S-COMP) is related to methotrexate (MTX) or to MTX and tumor necrosis factor-α (TNF-α) combination treatment for rheumatoid arthritis (RA); and to investigate whether S-COMP is related to cardiovascular risk factors including endothelial dysfunction and level of anticitrullinated protein antibodies (ACPA) in patients with RA.

METHODS

Clinical and laboratory measures, including S-COMP and reactive hyperemic index (RHI), were examined in 55 consecutive patients with RA starting with either MTX (n = 34) or MTX and anti-TNF-α treatment (n = 21) at baseline, and after 6 weeks and 6 months.

RESULTS

S-COMP was similar in the 2 treatment regimens during followup. We found a positive relationship between S-COMP at baseline and the use of disease-modifying antirheumatic drugs the last year preceding the study (p = 0.001), and a negative relation to current use of systemic glucocorticosteroids (p = 0.044). The nonsignificant change in S-COMP between baseline and the 6-month followup was positively and independently related to change in ACPA level (p = 0.009). There was no significant association between RHI and level of S-COMP at baseline.

CONCLUSION

The cartilage turnover marker S-COMP did not change significantly after 6 months' treatment with MTX with or without a TNF-α inhibitor in patients with RA. The positive association between S-COMP and ACPA suggests that these factors might interact, and could both be contributors to an unknown link between inflammation and cartilage destruction in patients with RA. S-COMP was not related to endothelial function in patients with RA, or to other cardiovascular risk factors studied. Clinical Trials registration number NCT00902005.

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.

Genome-wide association study of determinants of anti-cyclic citrullinated peptide antibody titer in adults with rheumatoid arthritis

We carried out a genome-wide association study of genetic predictors of anti-cyclic citrullinated peptide antibody (anti-CCP) level in 531 self-reported non-Hispanic Caucasian Rheumatoid Arthritis (RA) patients enrolled in the Brigham Rheumatoid Arthritis Sequential Study (BRASS). For replication, we then analyzed 289 single nucleotide polymorphisms (SNPs) with P < 0.001 in BRASS in an independent population of 849 RA patients from the North American Rheumatoid Arthritis Consortium (NARAC). BRASS and NARAC samples were genotyped using the Affymetrix 100K and Illumina 550K platforms respectively. Association between SNPs and anti-CCP titer was tested using general linear models. The five most significant SNPs from BRASS all were within the major histocompatibility complex (MHC) region (P < or = 3.5 x 10(-6)). After controlling for the human leukocyte antigen shared epitope (HLA-SE), the top SNPs still yielded P values < 0.0002. In NARAC, a single SNP from the MHC region near BTNL2 and HLA-DRA, rs1980493 (r(2) = 0.85 with the top five SNPs from BRASS), was associated significantly with CCP titer (P = 6.1 x 10(-5)) even after adjustment for the HLA-SE (P = 0.0002). The top SNPs found in BRASS and NARAC had r(2) = 0.46 and 0.64, respectively, to HLA-DRB1 DR3 alleles. These results confirm that the most significant genome region affecting anti-CCP titers in RA is the MHC region. We identified a SNP in moderate linkage disequilibrium (LD) with HLA-DR3, which may influence anti-CCP titer independently of the HLA-SE.

Cartilage and Bone Biomarkers in Rheumatoid Arthritis: Prediction of 10-year Radiographic Progression

Objective.

As current predictors of joint destruction have low specificity, serological biomarkers reflecting bone and cartilage destruction have been proposed as tools in assessing prognosis of rheumatoid arthritis (RA). We examined whether serum concentrations of a panel of biomarkers could predict radiographic progression in patients with RA.

Methods.

A cohort of 238 patients with RA was followed longitudinally for 10 years with collection of clinical data and serum samples. These analyses focus on the 136 patients with radiographs of the hands available at baseline and at 5 and/or 10 years. Radiographs were scored according to the van der Heijde-modified Sharp score (SHS). Baseline sera were analyzed for receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), human cartilage glycoprotein-39 (YKL-40), C2C, collagen cross-linked C-telopeptide (CTX-I), and cartilage oligomeric matrix protein (COMP). Multivariate linear and logistic regression analyses were used to identify predictors of radiographic progression.

Results.

Baseline CTX-I levels were higher in progressors [0.41 ng/ml (interquartile range 0.31–0.75)] than in nonprogressors [0.32 ng/ml (IQR 0.21–0.49)], and were independently associated with 10-year change in radiographic damage score [ß = 16.4 (IQR 5.7–27.1)]. We found no association between radiographic progression and baseline serum levels of RANKL, OPG, C2C, YKL-40, or COMP.

Conclusion.

This longterm followup study of patients with RA indicates a relationship between elevated CTX-I levels in serum and subsequent joint destruction. This association was, however, weak, and our study does not support that serum CTX-I or any of the other tested biomarkers will serve as more useful prognostic markers than current predictors such as anti-cyclic citrullinated peptide, radiographic damage early in the disease course, and signs of inflammation.

Diagnostic imaging guideline for musculoskeletal complaints in adults-an evidence-based approach-part 2: upper extremity disorders

PURPOSE

To develop evidence-based diagnostic imaging practice guidelines to assist chiropractors and other primary care providers in decision making for the appropriate use of diagnostic imaging for upper extremity disorders.

METHODS

A comprehensive search of the English and French language literature was conducted using a combination of subject headings and keywords. The quality of the citations was assessed using the Quality of diagnostic accuracy studies (QUADAS), the Appraisal of Guidelines Research and Evaluation (AGREE), and the Stroke Prevention and Educational Awareness Diffusion (SPREAD) evaluation tools. The Referral Guidelines for Imaging (radiation protection 118) coordinated by the European Commission served as the initial template. The first draft was sent for an external review. A Delphi panel composed of international experts on the topic of musculoskeletal disorders in chiropractic radiology, clinical sciences, and research was invited to review and propose recommendations on the indications for diagnostic imaging. The guidelines were pilot tested and peer-reviewed by practicing chiropractors and by chiropractic and medical specialists. Recommendations were graded according to the strength of the evidence. Dissemination and implementation strategies are discussed.

RESULTS

Recommendations for diagnostic imaging guidelines of adult upper extremity disorders are provided, supported by over 126 primary and secondary citations. The overall quality of available literature is low, however. On average, 44 Delphi panelists completed 1 of 2 rounds, reaching over 88% agreement on all 32 recommendations. Peer review by specialists reflected high levels of agreement and perceived ease of use of guidelines and implementation feasibility.

CONCLUSIONS

The guidelines are intended to be used in conjunction with sound clinical judgment and experience and should be updated regularly. Future research is needed to validate their content.

Aromatase inhibitor-associated arthralgia syndrome

Aromatase inhibitors (AIs) are widely used as an adjuvant endocrine treatment in postmenopausal women with early-stage breast cancer. Clinical trials have assessed 5 years of AI therapy, either as an alternative to tamoxifen for primary adjuvant therapy of breast cancer, or after 5 years of adjuvant tamoxifen. Treatment of 2-3 years' duration after 2-3 years of tamoxifen has also been studied. AI therapy brings side effects related to estrogen deprivation, and this side effect profile differs in clinically relevant ways from that seen with tamoxifen. In particular, the selective estrogen receptor modulatory effects of tamoxifen contribute to menopausal symptoms, vaginal discharge, and the rare but worrisome risks of thromboembolism and uterine carcinoma. By contrast, the low levels of estrogen achieved with aromatase inhibition contribute to menopausal symptoms, vaginal dryness and sexual dysfunction, and accelerated bone demineralization with risk of osteoporosis and osteoporotic fracture. Clinical experience also suggests that AI therapy is associated with a novel musculoskeletal side effect consisting of an arthralgia syndrome. The actual incidence of AI-associated arthralgias or musculoskeletal symptoms is not known, though such symptoms are quite prevalent and appear more commonly with AI use than with tamoxifen. Arthralgias can be a reason for discontinuation of AI treatment. The possible mechanisms of AI-associated arthralgia are unclear. Estrogen deficiency causes bone loss, which in turn contributes to arthralgia. Less well-studied functions of estrogen include regulating immune cells and cytokines involved in bone remodeling, and modulating pain sensitivity at the level of the central nervous system. Arthralgia and arthritis have seldom been rigorously differentiated in clinical trials of AIs. Assessment of inflammatory and rheumatologic markers, as well as detailed evaluation of patient symptoms using appropriate quality-of-life instruments, may be warranted in order to understand both the symptoms and the etiology of the arthralgia syndrome. Treatment options for arthralgia (primarily non-steroidal anti-inflammatory drugs) are currently inadequate, but areas of active research include high-dose vitamin D and new-targeted therapies to inhibit bone loss.