Anti-cyclic citrullinated peptide revised criteria for the classification of rheumatoid arthritis

Preclinical evaluation and pilot clinical study of [18F]AlF-NOTA-FAPI-04 for PET imaging of rheumatoid arthritis

PURPOSE

Fibroblast-like synoviocytes (FLSs) are key effector cells in the inflamed joints of patients with rheumatoid arthritis (RA). Previous studies have suggested that fibroblast activation protein (FAP) is highly expressed in RA-derived FLSs and is a specific marker of activated RA FLSs. In this study, we developed aluminum-[¹⁸F]-labeled 1,4,7-triazacyclononane-N,N',N″-triacetic acid-conjugated FAP inhibitor 04 ([¹⁸F]AlF-NOTA-FAPI-04) to image RA-FLSs in vitro and arthritic joints in collagen-induced arthritis (CIA) mice and RA patients.

METHODS

RA FLSs and NIH3T3 cells transfected with FAP were used to perform in vitro-binding studies. Biodistribution was conducted in normal DBA1 mice. Collagen-induced arthritis (CIA) models with different arthritis scores were subjected to [¹⁸F]AlF-NOTA-FAPI-04 and ¹⁸F-FDG PET imaging. Histological examinations were performed to evaluate FAP expression and Cy3 dye-labeled FAPI-04(Cy3-FAPI-04) uptake. Blocking studies with excess unlabeled FAPI-04 in CIA mice and NIH3T3 xenografts in immunocompromised mice were used to evaluate the binding specificity of [¹⁸F]AlF-NOTA-FAPI-04. Additionally, [¹⁸F]AlF-NOTA-FAPI-04 PET imaging was performed on two RA patients.

RESULTS

The binding of [¹⁸F]AlF-NOTA-FAPI-04 increased significantly in RA FLSs and NIH3T3 cells overexpressing FAP compared to their parental controls (^FAP-GFP-NIH3T3 vs. ^GFP-NIH3T3, 2.40 ± 0.078 vs. 0.297 ± 0.05% AD/10⁵ cells; RA FLSs vs. OA FLSs, 1.54 ± 0.064 vs. 0.343 ± 0.056% AD/10⁵ cells). Compared to ¹⁸F-FDG imaging, [18F]AlF-NOTA-FAPI-04 showed high uptake in inflamed joints in the early stage of arthritis, which was positively correlated with the arthritic scores (Pearson r=0.834, P<0.001). In addition, the binding of [¹⁸F]AlF-NOTA-FAPI-04 to cells with high FAP expression and the uptake of [¹⁸F]AlF-NOTA-FAPI-04 in arthritic joints both could be blocked by excessive unlabeled FAPI-04. Fluorescent staining showed that the intensity of Cy3-FAPI-04 binding to FAP increased accordingly as the expression of FAP protein increased in cells and tissue sections. Furthermore, the uptake of [¹⁸F]AlF-NOTA-FAPI-04 in ^FAP-GFP-NIH3T3 xenografts was significantly higher than that in ^GFP-NIH3T3 xenograft (35.44 ± 4.27 vs 7.92 ± 1.83% ID/mL). Finally, [¹⁸F]AlF-NOTA-FAPI-04 PET/CT imaging in RA patients revealed nonphysiologically high tracer uptake in the synovium of arthritic joints.

CONCLUSION

[¹⁸F]AlF-NOTA-FAPI-04 is a promising radiotracer for imaging RA FLSs and could potentially complement the current noninvasive diagnostic parameters.

Isopsoralen ameliorates rheumatoid arthritis by targeting MIF

BACKGROUND

Isopsoralen (IPRN), one of the active ingredients of Psoralea corylifolia Linn, has anti-inflammatory properties. We attempted to investigate the inhibitory effects of IPRN on rheumatoid arthritis (RA) and characterize its potential mechanism.

METHODS

RA fibroblast-like synoviocytes (FLSs) and mice with collagen-induced arthritis (CIA) were used as in vitro and in vivo models to analyze the antiarthritic effect of IPRN. Histological analysis of the inflamed joints from mice with CIA was performed using microcomputed tomography (micro-CT) and hematoxylin-eosin (HE) staining. RNA sequencing (RNA-Seq), network pharmacology analysis, molecular docking, drug affinity responsive target stability (DARTS) assay, and cellular thermal shift assay (CETSA) were performed to evaluate the targets of IPRN.

RESULTS

IPRN ameliorated the inflammatory phenotype of RA FLSs by inhibiting their cytokine production, migration, invasion, and proangiogenic ability. IPRN also significantly reduced the severity of CIA in mice by decreasing paw thickness, arthritis score, bone damage, and serum inflammatory cytokine levels. A mechanistic study demonstrated that macrophage migration inhibitory factor (MIF), a key protein in the inflammatory process, was the specific target by which IPRN exerted its anti-inflammatory effects in RA FLSs.

CONCLUSION

Our study demonstrates the antiarthritic effect of IPRN, which suggests the therapeutic potential of IPRN in RA.

Is ACPA positivity the main driver for rheumatoid arthritis treatment? Pros and cons

Rheumatoid Arthritis (RA) is an autoimmune chronic disease that is characterized by the positivity of various antibodies, the most specific being autoantibodies against citrullinated antigens (ACPA). Despite ACPA are not arthritogenic by themselves, ACPA positive individuals have high risk of RA development and ACPA positivity is associated with severe erosive phenotype and higher mortality rate compared to seronegative RA. Moreover, ACPA status is associated with favorable response to biologics targeting pathways involving autoantibody producing cells as B lymphocytes. In the current review we have discussed the pros and cons on the available scientific evidences, regarding the diagnostic, prognostic and management implications of ACPAs in RA.

Establishment of a decision tree model for diagnosis of early rheumatoid arthritis by proteomic fingerprinting

AIM

The objective of this study was to identify proteomic biomarkers specific for rheumatoid arthritis (RA) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in combination with weak cationic exchange (WCX) magnetic beads.

METHODS

Serum samples from 50 patients with RA and 110 disease controls (50 SLE and 60 SS) and 51 healthy individuals were analyzed. The samples were randomly divided into a training set or test set to develop a diagnostic model for RA.

RESULTS

A total of 83 protein peaks were identified to be related with RA, in which four of the peaks with mass-charge ratio (m/z) at 8133.85, 5844.60, 13 541.3 and 14 029.0 were selected to establish a model for diagnosis of RA. This classification model could separate patients with RA from diseased and healthy controls with sensitivity of 84.0% and specificity of 92.5%, and its accuracy was confirmed in the blind testing set with high sensitivity and specificity of 80.0% and 93.3%, respectively.

CONCLUSIONS

This study suggested that potential serum biomarkers for RA diagnosis could be discovered by MALDI-TOF-MS. The classification tree model set up in this study might be used as a novel diagnostic tool for RA.

The challenge of using the rheumatoid arthritis diagnostic criteria in clinical practice

The new 2010 ACR/EULAR (American College of Rheumatology/European League Against Rheumatism) criteria of Rheumatoid Arthritis recently published, have been released to classify and identify patients with early RA who could benefit from early therapy. They recommend anti-citrullinated protein antibody (ACPA) testing as an alternative criterion to Rheumatoid Factor (RF) and ACPA that were introduced together with the other classic criteria in a scoring system. We previously criticized these new criteria because of unavailable specificity and sensibility in the first paper, and the use of ACPA as dichotomous criterion (presence/absent) and alternatives to rheumatoid factor. Our previous work promoted discussion and fostered new research on this issue. By the light of new data, in an effort to improve clinical reasoning, we suggest a more practical probabilistic point of view. In this regard, we analyze the sensitivity and specificity of the diagnostic studies that evaluate the performance of the 2010 classification criteria. Then, we compare the old and the new classification criteria. Subsequently, we describe the use of likelihood ratios applied to the classification criteria and different cutoff levels of ACPA for decision-making in different setting. Moreover, we define some properties of likelihood ratios and their use for diagnosing or excluding rheumatoid arthritis. We want to share this kind of knowledge within the scientific community because we believe that it can help general practitioners and specialists to recognize early arthritis patients implementing a more efficient probabilistic clinical reasoning.

Validation of the 2010-ACR/EULAR -classification criteria using newly EULAR-defined erosion for rheumatoid arthritis on the very early arthritis community-based (VErA) cohort

OBJECTIVE

To validate the 2010-ACR/EULAR criteria for rheumatoid arthritis (RA), taking into account the recent EULAR definition of "erosive disease", on the 310 patients comprising the very early arthritis cohort (VErA).

METHODS

2010-criteria performances were tested by first strictly applying its three items successively: ≥ 1 clinical synovitis/another disease(s)/score ≥ 6/10), then the typical erosion grid without obtaining a score of ≥ 6 to diagnose RA. We tested successively: no erosion (S1), ≥ 1 erosion(s) (S2), EULAR-defined erosive disease (S3). Two gold standards were used: expert diagnosis at six years and EULAR erosive disease at two years.

RESULTS

At inclusion, median age was 52 years; median RA duration 4.2 months. 2010-ACR/EULAR criteria, including EULAR-defined erosive disease applied at baseline, classified comparable numbers of patients as the 1987 criteria (P=0.27). Using expert diagnosis at six years, more patients were classified as RA with S2 than 1987-ACR criteria (P<0.04). In contrast, sensitivity and specificity indicated that 2010-ACR/EULAR-S3 criteria performed slightly but not significantly better than 1987-ACR criteria. On ROC curves, a score ≥ 6 correctly classified RA. When EULAR-defined erosion at two years was the gold standard, the 1987-ACR, the 2010-S1, -S2 and -S3 criteria performed comparably.

CONCLUSIONS

Using the very early community-based, conservatively treated VErA cohort, the strict application of 2010-ACR/EULAR criteria using the new EULAR definition of erosive disease or not performed slightly but not significantly better than the 1987-ACR criteria.

Low-field magnetic resonance imaging or combined ultrasonography and anti-cyclic citrullinated peptide antibody improve correct classification of individuals as established rheumatoid arthritis: results of a population-based, cross-sectional study

BACKGROUND

The aim of the present study was to evaluate the accuracy of two approaches using magnetic resonance imaging (MRI) or combined ultrasonography (US) and anti-cyclic citrullinated peptide antibody (ACPA) for diagnosis and classification of individuals with established rheumatoid arthritis (RA).

METHODS

In 53 individuals from a population-based, cross-sectional study, historic fulfilment of the American College of Rheumatology (ACR) 1987 criteria ("classification") or RA diagnosed by a rheumatologist ("diagnosis") were used as standard references. The sensitivity, specificity and Area under Curve for Receiver Operating Characteristics curves (ROC-area: (sensitivity + specificity)/2) were calculated for "current fulfilment of the ACR 1987 criteria" (list format), "adapted ACR 1987 criteria" (list format, substituting IgM rheumatoid factor with ACPA and clinical joint swelling and erosions on radiography with synovitis and erosions detected by US on a semi-quantitative scale), and RA MRI scoring System (RAMRIS) scores on low-field MRI in the unilateral hand.

RESULTS

For the ACR 1987 criteria the ROC-area was 75% (sensitivity/specificity = 50%/100%) (with "classification" as standard reference) and 69% (44%/94%) (with "diagnosis" as standard reference), while for the adapted ACR 1987 criteria it was 86% (75%/97%) (classification) and 82% (72%/91%) (diagnosis). For RAMRIS synovitis score in metacarpophalangeal (MCP) joints only (cut-off ≥5), the ROC-area (sensitivity/specificity) was 78% (62%/94%) (classification) and 85% (69%/100%) (diagnosis), while for the total synovitis score of MCP joints plus wrist (cut-off ≥10) it was 78% (62%/94%) (both classification and diagnosis).

CONCLUSIONS

Compared with the ACR 1987 criteria, low-field MRI alone or adapted criteria incorporating US and ACPA increased the correct classification and diagnosis of RA.

Soft tissue swellings in the foot: rheumatoid nodulosis

Background rheumatoid nodulosis is a rare disease characterised by multiple subcutaneous nodules, a high titre of rheumatoid factor, radiologically detectable cystic bone lesions, but with none or few of the systemic manifestations or joint activity of rheumatoid disease. Histopathologically, nodulosis is the same as the nodules found in rheumatoid arthritis. It is considered to be a benign variant of rheumatoid arthritis. A 69 year old male presents with multiple subcutaneous nodules on the feet. This case study highlights the benefits of ultrasound in establishing a correct diagnosis and management. Although rare, rheumatoid nodulosis is a consideration in the differential diagnoses of soft tissue swellings in the feet.

Diagnosis of lumbar spinal stenosis: an updated systematic review of the accuracy of diagnostic tests

STUDY DESIGN

Systematic review of diagnostic studies.

OBJECTIVE

To update our previous systematic review on the diagnostic accuracy of tests used to diagnose lumbar spinal stenosis.

SUMMARY OF BACKGROUND DATA

A wide range of clinical, radiological, and electrodiagnostic tests are used to diagnose lumbar spinal stenosis. An accurate diagnosis is vital, because lumbar spinal stenosis may require specific medical advice and treatment. Therefore, it is important to know the accuracy of these diagnostic tests currently available.

METHODS

A comprehensive literature search was conducted for original diagnostic studies on lumbar spinal stenosis, in which one or more diagnostic tests were evaluated with a reference standard, and diagnostic accuracy was reported or could be calculated. Our previous systematic review included studies up to March 2004; this review is current up to March 2011. Included studies were assessed for their methodological quality using the QUADAS tool. Study characteristics and reported diagnostic accuracy were extracted.

RESULTS

Twenty-two additional articles in addition to the 24 included in the previous review met the inclusion criteria. Combined, this resulted in 20 articles concerning imaging tests, 11 articles evaluating electrodiagnostic tests, and 15 articles evaluating clinical tests. Estimates of the diagnostic accuracy of the tests differed considerably.

CONCLUSION

There is a need for a consensus on criteria to define and classify lumbar spinal stenosis. At present, the most promising imaging test for lumbar spinal stenosis is magnetic resonance imaging, avoiding myelography because of its invasiveness and lack of superior accuracy. Electrodiagnostic studies showed no superior accuracy for conventional electrodiagnostic testing compared with magnetic resonance imaging. These tests should be considered in the context of those presenting symptoms with the highest diagnostic value, including radiating leg pain that is exacerbated while standing up, the absence of pain when seated, the improvement of symptoms when bending forward, and a wide-based gait.

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

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

Diagnostic value of anti-cyclic citrullinated peptide antibody for rheumatoid arthritis in a Chinese population: a meta-analysis

To use meta-analysis to determine the accuracy of anti-cyclic citrullinated peptide (CCP) antibody in diagnosis of patients with rheumatoid arthritis (RA) in a Chinese population, we searched MEDLINE and CNKI databases for studies published in English or Chinese between January 2000 and June 2010. Two investigators independently evaluated studies for inclusion, data extraction, and quality assessment. We used a random-effects model to combine estimates of sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), and diagnostic odds ratio (DOR). One hundred and eighteen studies met our inclusion criteria. All studies were of high quality. The summary estimates for anti-CCP antibody in the diagnosis of RA in a Chinese population were as follows: sensitivity 0.65 (95% confidence interval (CI) 0.65-0.66), specificity 0.95 (95% CI 0.95-0.96), positive likelihood ratio (LR+) 15.84 (95% CI 13.55-18.54), negative likelihood ratio (LR-) 0.33 (95% CI 0.31-0.35), and diagnostic odds ratio (DOR) 51.60 (95% CI 43.64-61.01). With high specificity and moderate sensitivity, anti-CCP antibody tests play an important role in conforming the diagnosis of RA in a Chinese population.

Diagnostic Accuracy of ACR/EULAR 2010 Criteria for Rheumatoid Arthritis in a 2-Year Cohort

Objective.

To evaluate the diagnostic accuracy of the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) and 1987 ACR criteria for rheumatoid arthritis (RA), and the respective role of the algorithm and scoring of the ACR/EULAR.

Methods.

In total, 270 patients with recent-onset arthritis of < 1 year duration were included prospectively between 1995 and 1997 and followed for 2 years. RA was defined as the combination, at completion of followup, of RA diagnosed by an office-based rheumatologist and treatment with a disease-modifying antirheumatic drug or glucocorticoid. We compared the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the criteria sets in the overall population, in the subgroup meeting the tree condition for ACR/EULAR scoring, and in the overall population classified according the full tree.

Results.

At baseline, 111 of the 270 patients had better alternative diagnoses and 16 had erosions typical for RA; of the 143 remaining patients, 52 had more than 6 ACR/EULAR 2010 points (indicating definite RA) and 91 had fewer than 6 points. After 2 years, 11/16 patients with erosions and 40/52 with more than 6 points had RA. 100 of the 270 patients met the reference standard for RA. Sensitivity, specificity, PPV, and NPV of the ACR/EULAR (full tree) were 51/100 (51%), 153/170 (90%), 51/68 (75.4%), and 153/202 (75.7%), respectively. Diagnostic accuracies of the ACR/EULAR score and ACR 1987 criteria were not statistically different.

Conclusion.

Much of the improvement of the ACR/EULAR criteria was ascribable to the use of exclusion criteria in the algorithm.

Is It Necessary to Combine Detection of Anticitrullinated Protein Antibodies in the Diagnosis of Rheumatoid Arthritis?

Objective.

Antibodies against citrulline-containing epitopes, such as antiperinuclear factor (APF), antikeratin antibodies (AKA), antifilaggrin antibodies, and anticyclic citrullinated peptide (anti-CCP) antibodies, are specific in rheumatoid arthritis (RA). Detection of APF, AKA, and anti-CCP has been widely used in clinical practice. However, studies on combined detection of these anti citrullinated protein antibodies (ACPA) in the significance of diagnosing RA have been limited. We aimed to detect APF, AKA, and anti-CCP antibodies and to evaluate the significance of combined detection of these ACPA in RA.

Methods.

A total of 551 patients with arthritic disorders, 304 with RA and 247 with other rheumatic diseases, were selected at the Department of Rheumatology and Immunology during the past 2 years. AKA and APF were tested by indirect immunofluorescence assay. Anti-CCP was detected using the second-generation ELISA kit.

Results.

The sensitivities of anti-CCP, AKA, and APF tests for RA were 76.2%, 43.4%, and 34.5%, respectively, while the specificities were 96.0%, 98.4%, and 99.6%. The combination of anti-CCP, AKA, and APF positivity had the highest specificity (100%), but it yielded a low sensitivity (28.3%). When 2 of the 3 ACPA were positive, the sensitivity and specificity were 48.4% and 99.2%, respectively. When either anti-CCP or AKA or APF was positive, sensitivity increased to 77.3%, but specificity decreased to 94.7%.

Conclusion.

Anti-CCP was the most valuable marker in the diagnosis of RA, among the 3 ACPA. Combined detection of anti-CCP, AKA, and APF did not increase the diagnostic capability for RA.

Correlation of anti-cyclic citrullinated antibody with hand joint erosion score in rheumatoid arthritis patients

BACKGROUND/AIMS

To examine the correlation between radiological joint damage and serological parameters in early rheumatoid arthritis (RA).

METHODS

This retrospective study reviewed the records of 216 patients diagnosed with RA and classified them according to disease duration: group 1, </= 24 months; group 2, > 24 months; and group 3, all patients combined. The extent of joint damage was assessed from plain radiographs using a modified version of the Larsen method and compared among groups.

RESULTS

The mean radiographic joint damage score was significantly higher in patients who had established RA (10.1 points) compared with those who had early RA. In group 1, the inflammatory parameters, erythrocyte sedimentation rate, and C-reactive protein were positively correlated with the joint damage score, but rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibody were not. A subgroup analysis revealed that the anti-CCP positive patients in groups 1 and 2 had greater joint damage scores than did the anti-CCP negative patients, but no difference in RF was observed between subgroups. Anti-CCP positivity was not significantly correlated with joint damage sores in group 3.

CONCLUSIONS

Anti-CCP positivity was significantly correlated with more severe joint damage at diagnosis. A correlation was observed between the radiological joint damage score and inflammatory parameters in early and established RA, indicating that anti-CCP can serve as a diagnostic tool and predict structural joint damage. These findings suggest anti-CCP positive patients should receive aggressive therapeutic intervention.

Variation in eligibility criteria from studies of radiculopathy due to a herniated disc and of neurogenic claudication due to lumbar spinal stenosis: a structured literature review

STUDY DESIGN

A structured literature review.

SUMMARY OF THE BACKGROUND DATA

Widely recognized classification criteria for rheumatologic disorders have resulted in well-defined patient populations for clinical investigation.

OBJECTIVE

We sought to determine whether similar criteria were needed for back pain disorders by examining variability in eligibility criteria in published studies.

METHODS

Studies involving radiculopathy due to lumbar herniated disc (HD) and for neurogenic claudication due to lumbar spinal stenosis (LSS) were identified. Randomized controlled trials published between January 1, 2006 and October 1, 2008 in select peer reviewed journals were retrieved, their eligibility criteria were identified and categorized.

RESULTS

Twelve eligible HD studies were identified. Thirteen unique categories of eligibility criteria were identified with a mean of 3.9 (+/-2.0) and a range from 0 to 8 categories per study. More categories were present for studies that included nonsurgical (5.6 +/- 2.5) treatment for studies with only surgical treatment (2.6 +/- 1.7) P = 0.04). Seven LSS studies met eligibility criteria, and 9 unique categories were identified. A mean of 5.0 (+/-2.2) categories with a range from 2 to 7 was used per study.

CONCLUSION

Wide variation in the number and type of eligibility criteria from randomized clinical trials of well defined back pain syndromes was identified. These results support the need for developing and disseminating international classification criteria for these clinical conditions.

The use of citrullinated peptides and proteins for the diagnosis of rheumatoid arthritis

The presence or absence of antibodies to citrullinated peptides/proteins (ACPA) is an important parameter that helps a clinician set a diagnosis of early rheumatoid arthritis and, hence, initiate treatment. There are several commercial tests available to measure ACPA levels, although it can be difficult to decide what the best test for a given clinical question is. We analyzed literature data in which the diagnostic and other properties of various ACPA tests are compared. The results show that for diagnostic purposes the CCP2 test has the highest specificity, the highest sensitivity in stratified studies and the highest positive predictive value. For the prediction of future joint destruction the CCP2, MCV, and CCP3 tests may be used. The ability to predict the likelihood of not achieving sustained disease-modifying antirheumatic drug-free remission was highest for the CCP2 test. Finally, the levels of anti-CCP2 and anti-CCP3 (and possibly anti-mutated citrullinated vimentin) in rheumatoid arthritis patients are not significantly influenced by TNFalpha blocking agents.

Identification of undiagnosed inflammatory arthritis in a community health fair screen

OBJECTIVE

To identify individuals with undiagnosed inflammatory arthritis (IA) and rheumatoid arthritis (RA) in a community health fair screen, and to establish in a health fair setting the diagnostic accuracy of combinations of the Connective Tissue Disease Screening Questionnaire (CSQ) and autoantibody testing for IA.

METHODS

Screening for IA/RA was performed at health fair sites using a combination of the CSQ, joint examination, rheumatoid factor, and anti-cyclic citrullinated peptide (anti-CCP) antibody testing. IA was defined as > or =1 swollen joint suggestive of synovitis on joint examination by a trained clinician.

RESULTS

Six hundred one subjects were screened; 51.0% participated because of joint symptoms (pain, stiffness, or swelling). Eighty-four subjects (14.0%) had > or =1 swollen joint, designated as IA on joint examination. Of the 601 subjects screened, 9 (1.5%) had IA and met > or =4 of 7 American College of Rheumatology criteria for RA but had no prior diagnosis of RA, and 15 (2.5%) had IA and RF and/or anti-CCP positivity, suggesting early RA. The diagnostic accuracy of combinations of the CSQ and autoantibody testing for the identification of IA yielded maximal sensitivity, specificity, and positive and negative predictive values of 95.3%, 99.2%, 71.4%, and 97.7%, respectively.

CONCLUSION

Health fair screening may be an effective approach for the identification of individuals with undiagnosed IA/RA. A combination of the CSQ and autoantibody testing alone has clinically useful diagnostic accuracy for the detection of IA. Decisions regarding which methodology to use for future health fair IA/RA screening will depend on goals of screening and funding.

Anti-citrullinated peptide antibody assays and their role in the diagnosis of rheumatoid arthritis

Increasingly, assays for the detection of anti-citrullinated peptide antibodies (ACPA) are used in RA diagnosis. This review summarizes the biologic basis and development of ACPA assays, available ACPA assays and their performance characteristics, and diagnostic properties of ACPA alone and compared to rheumatoid factor (RF) in early RA. We also review correlations, precision, costs and cost-effectiveness, availability, stability and reproducibility of the available assays. Taken together, data indicate that ACPA has a higher specificity than RF for early RA, good predictive validity, high sensitivity, apparent cost-effectiveness and good stability and reproducibility. Given its superior performance characteristics and increasing availability, ACPA is emerging as the most useful single assay for the diagnosis of RA.

Changes Over Time in the Diagnosis of Rheumatoid Arthritis in a 10-year Cohort

Objective.

We assessed levels of agreement between a diagnosis of rheumatoid arthritis (RA) at inclusion in a recent-onset arthritis cohort, then 2 and 10 years later. Performance of American College of Rheumatology (ACR) criteria alone or combined with rheumatologist diagnosis, and of recent new criteria adding antibodies to cyclic citrullinated peptides (“anti-CCP-revised criteria”) to existing ACR criteria, was evaluated.

Methods.

In total, 270 patients with recent-onset arthritis of less than 1 year duration were included between 1995 and 1997 and followed for 2 years. A diagnosis was recorded by an office-based rheumatologist (OBR) at inclusion, then 2 years later. In 2007, a questionnaire was sent to each rheumatologist to collect the final diagnosis, which was considered the reference.

Results.

Final diagnosis was available for 164 patients: 57 had RA. Agreement was low (κ = 0.27) between the baseline and final diagnoses, and substantial (κ = 0.69) between the 2-year and final diagnoses. Anti-CCP-revised criteria had sensitivity of 65% to 81% and specificity of 55% to 75%. Sensitivity and specificity of ACR criteria were 57.9% (44.1%–70.9%) and 74.8% (65.5%–82.7%) at inclusion, 80.7% (70.5%–90.0%) and 63.6% (54.5%–72.7%) at 2 years. The combination OBR diagnosis/ACR criteria after 2 years showed considerably increased specificity (87% vs 64%) and slightly decreased sensitivity (77% vs 81%).

Conclusion.

ACR criteria for RA showed poor performance even at 2 years. The absence of exclusion criteria may explain the lack of specificity, which improved when combined with the OBR diagnosis. Adding anti-CCP criteria to the existing criteria could help in diagnosing RA.

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.

Early inflammatory arthritis versus rheumatoid arthritis

PURPOSE OF REVIEW

Rheumatoid arthritis (RA) has started to be perceived as a potentially curable condition with early, aggressive use of disease-modifying antirheumatic drugs. We review the pathophysiological concepts of RA development, the technological advances used to estimate the individual risk of progression to RA, and the impact of antirheumatic therapy for patients presenting with early inflammatory arthritis.

RECENT FINDINGS

The finding of a strong gene-environment interaction has modified our concepts of RA pathogenesis and opened new opportunities for disease prevention and therapeutic interventions. Anticyclic citrullinated antibodies and prediction rules have improved our ability to estimate the risk of progression to RA in individual patients presenting with early inflammatory arthritis. In patients at high risk of developing RA, results from trials suggest that treating these patients with potent antirheumatic therapies may slow the progression from early inflammatory arthritis to definite RA and inhibit the progression of joint damage.

SUMMARY

Early inflammatory arthritis is a critical period of the disease, during which therapy may have a durable effect and change the natural course of the condition. Physicians need to assess the individual risk of progression to RA in patients presenting with early inflammatory arthritis and consider initiating early disease-modifying antirheumatic drug therapy in patients at high risk of developing RA.

Comparative performance analysis of 4 different anti-citrullinated protein assays in the diagnosis of rheumatoid arthritis

OBJECTIVE

To evaluate the diagnostic performances of 2 recently developed assays, third-generation anti-cyclic citrullinated peptide (anti-CCP3) and anti-mutated citrullinated vimentin (anti-MCV), in comparison to conventional second-generation anti-cyclic citrullinated peptide (anti-CCP2) assay; and to assess a novel fully automated, random-access AxSYM anti-CCP assay for early diagnosis of rheumatoid arthritis (RA).

METHODS

A cohort of 176 patients was enrolled in our study; 93 were diagnosed as having RA. The non-RA group consisted of 83 patients including 38 with systemic lupus erythematosus, 17 with primary Sjögren's syndrome, 11 with osteoarthritis, and 17 healthy controls. All were tested for presence of anti-CCP2, anti-CCP3, AxSYM anti-CCP, anti-MCV, and rheumatoid factor (RF)-IgM according to the manufacturers' instructions.

RESULTS

Diagnostic performance of the assays revealed the highest area under the curve for the novel AxSYM anti-CCP [89.1; 95% confidence interval (CI) 84.3-93.8], followed by anti-CCP3 (86.7; 95% CI 81.6-91.9), anti-CCP2 (82; 95% CI 75.8-88.3), and anti-MCV (71.9; 95% CI 64.4-79.5). The sensitivities and specificities were 60.2% and 98.8% for anti-CCP2, 61.3% and 97.6% for anti-CCP3, 80.6% and 84.3% for AxSYM anti-CCP, 49.8% and 91.6% for anti-MCV, and 67.8% and 91.6% for RF-IgM, respectively.

CONCLUSION

At cutoff of 5 U/ml, AxSYM anti-CCP emerged as a highly sensitive first-line early diagnostic tool for RA, with the greatest discrimination power, above 16 U/ml, in case of positive result. Using a single easily performed automated assay at 2 determined decision limits we were able to diagnose 81% of cases of RA and missing only 1.2%.