The role of anti-mutated citrullinated vimentin antibodies in the diagnosis of early rheumatoid arthritis

Risk Factors Analysis for the Development of Hypocomplementemia in Rheumatoid Arthritis Patients: A Single-Center Retrospective Study

Objective

The purpose of the research was to explore the possible risk factors for the development of hypocomplementemia (HC) in rheumatoid arthritis (RA) patients by analyzing their clinical and laboratory features.

Methods

This retrospective research contained 501 RA patients, divided into RA patients with HC (n=78) and RA patients without HC (n=423). Demographic characteristics and laboratory test results of RA patients were collected and analyzed, such as age, sex, anti-mutated citrullinated vimentin antibody (Anti-MCV), serum complements (C3, C4), immunoglobulins (IgA, IgG, IgM), hemoglobin (Hb), platelets (PLT) and erythrocyte sedimentation rate (ESR), etc. Spearman correlation was served as assessing the correlations of the levels of serum C3 and C4 with each index. Receiver operating characteristic (ROC) curves were served as assessing the diagnostic efficacy of each index for RA patients with HC. Furthermore, risk factors for the occurrence of HC in RA patients were analyzed by employing binary logistic regression of single and multiple factors.

Results

Compared RA patients with HC to without HC, the former were older and had a longer disease duration with increased levels of Anti-MCV, IgM and DAS28 and lower levels of Hb, PLT and ESR; Spearman correlation analysis verified the level of serum Anti-MCV was a negative correlation with C3 (r=-0.156); the area under the ROC curve (AUC) of PLT in diagnosing RA patients with HC was the largest at 0.65 (95% CI: 0.60-0.69); binary logistic regression analysis indicated that advanced age (>66 years), long disease duration (>62 months), high DAS28 value (>6.13), the levels of Anti-MCV>107.68IU/mL, IgM>1.54g/L, ESR≤69.00mm/h, Hb≤99.00g/L and PLT≤305.00×109/L were probable risk factors for the occurrence of HC in RA patients.

Conclusion

Age and disease duration, DAS28, Anti-MCV, IgM, ESR, Hb, and PLT are closely related to the development of HC in RA patients. Timely monitoring of these indicators can help to evaluate disease activity of RA patients and further improve their prognosis.

A study of the roles of some immunological biomarkers in the diagnosis of rheumatoid arthritis

Autoimmune rheumatoid arthritis (RA) is a systemic condition closely correlated with a variety of autoantibodies (Abs) that could be considered diagnostic and prognostic markers. The current research was designed to detect the diagnostic values for a number (n) of these auto-Abs in RA detection and to evaluate the accuracy of a combined diagnostic scheme. This prospective study was conducted between September 2021 and August 2022 and included 110 subjects with RA, 70 individuals with other autoimmune disorders as positive controls (PC), and 50 unrelated, apparently healthy individuals as healthy controls (HC). The eligibility criteria for all study groups were followed stringently. An enzyme-linked immunosorbent assay (ELISA) was employed to measure rheumatoid factors (RF), cyclic citrullinated peptide antibodies (CCP-Abs), mutated citrullinated vimentin antibodies (MCV-Abs), anti-perinuclear factor antibodies (APF-Abs), and anti-keratin antibodies (AKA). We calculated the specificity, sensitivity, and predictive values of all auto-Abs. Significantly higher levels of anti-CCP-Abs, anti-MCV-Abs, APF-Abs, and AKAs were reported in the RA patients compared to the HC and PC subjects. RF levels, however, were only statistically elevated when compared to the HC individuals. Anti-APF-Abs had a higher sensitivity rate (70.9%), and anti-CCP-Abs had a higher specificity rate (94.16%) compared to other auto-Abs, whereas the combined detection scheme revealed a higher sensitivity (81.81%) and excellent specificity (90.83%) compared to the two former auto-Abs. Anti-perinuclear factor-Ab was a highly sensitive test, and CCP-Ab was a surpassingly specific assay for identifying RA. Furthermore, the combined detection scheme is an essential serological approach for RA diagnosis and crucial in differentiating this disease from other autoimmune diseases, thus promoting early diagnosis and treatment.

Anti-vimentin antibodies are associated with higher severity of Sjögren's disease

Vimentin is a ubiquitously present Type III intermediate filament protein, often targeted by autoimmune responses in multiple rheumatic disorders. Although previous studies have reported anti-vimentin antibodies in Sjögren's disease (SjD) patients, the clinical significance of such antibodies is unknown. To address this issue, the presence of anti-vimentin antibodies was determined in serum samples from a well-characterized cohort of primary SjD patients, non-SjD Sicca, and healthy controls. The occurrence of anti-vimentin antibodies and their association with different clinical features of the disease were evaluated. Anti-vimentin antibodies were detected in 24% of primary SjD patients, compared to 4% in non-SjD sicca patients and 3% in healthy controls. In primary SjD patients, higher levels of anti-vimentin antibodies were significantly associated with reduced saliva and tear flow and severe ocular surface damage indicators. The anti-vimentin antibody levels did not show significant associations with the presence or absence of other autoantibodies like ANA, RF, and anti-Ro/La. Our data suggest that the anti-vimentin antibody specificity arises in a subset of primary SjD patients and is associated with oral and ocular features of the disease. Anti-vimentin can potentially serve as a novel biomarker for evaluating the severity of salivary and lacrimal gland dysfunction in primary SjD.

Diagnostic value of anti-cyclic citrullinated peptide antibody combined with rheumatoid factor in rheumatoid arthritis in Asia: a meta-analysis

Objective

This meta-analysis explored the diagnostic value of anti-cyclic citrullinated peptide antibody (anti-CCP) and rheumatoid factor (RF) for rheumatoid arthritis (RA) in the Asian population.

Methods

Embase, Medline, Cochrane Library, Chinese Science and Technology Periodicals, China National Knowledge Infrastructure, and China Wanfang Databases were searched from 1 January 2000 to 1 February 2021 to collect studies on the combined detection of anti-CCP and RF for diagnosing RA. The sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (+LR), and negative likelihood ratio (−LR) were combined and analyzed. Summary receiver operating characteristic (SROC) curves were drawn.

Results

Twenty-four published papers were analyzed, including 21 combined in series and 8 combined in parallel. In the tandem analysis, the sensitivity = 0.64 [95% confidence interval (CI): 0.58–0.70], specificity = 0.97 (95%CI: 0.95–0.98), +LR = 19.70 (95%CI: 12.74–30.46), −LR = 0.37 (95%CI: 0.31–0.43), DOR = 53.43 (95%CI: 34.46–82.40), and area under the SROC curve = 0.89. In the parallel combination, the sensitivity = 0.87 (95%CI: 0.80–0.92), specificity = 0.76 (95%CI: 0.67–0.84), +LR = 3.68 (95%CI: 2.62–5.17), −LR = 0.17 (95%CI: 0.11–0.26), DOR = 21.56 (95%CI: 11.63–39.99), and area under the SROC curve = 0.89.

Conclusion

Anti-CCP and RF combined detection improves the diagnostic efficiency of RA, providing a potential strategy for early clinical screening in the Asian population.

This trial was retrospectively registered in the INPLASY/Research Registry (https: //inplasy.com/) with the registration number INPLASY202180106.

Immune cells in lens injury repair and fibrosis

Immune cells, both tissue resident immune cells and those immune cells recruited in response to wounding or degenerative conditions, are essential to both the maintenance and restoration of homeostasis in most tissues. These cells are typically provided to tissues by their closely associated vasculatures. However, the lens, like many of the tissues in the eye, are considered immune privileged sites because they have no associated vasculature. Such absence of immune cells was thought to protect the lens from inflammatory responses that would bring with them the danger of causing vision impairing opacities. However, it has now been shown, as occurs in other immune privileged sites in the eye, that novel pathways exist by which immune cells come to associate with the lens to protect it, maintain its homeostasis, and function in its regenerative repair. Here we review the discoveries that have revealed there are both innate and adaptive immune system responses to lens, and that, like most other tissues, the lens harbors a population of resident immune cells, which are the sentinels of danger or injury to a tissue. While resident and recruited immune cells are essential elements of lens homeostasis and repair, they also become the agents of disease, particularly as progenitors of pro-fibrogenic myofibroblasts. There still remains much to learn about the function of lens-associated immune cells in protection, repair and disease, the knowledge of which will provide new tools for maintaining the core functions of the lens in the visual system.

Circulating Vimentin Is Associated With Future Incidence of Stroke in a Population-Based Cohort Study

BACKGROUND AND PURPOSE

VIM (vimentin) is a cytoskeletal intermediate filament protein, which has been linked to atherosclerosis and thrombosis; both are important causes of stroke. We examined the relationship between circulating VIM and incidence of stroke, and if carotid plaque could modify the association in a prospective population-based cohort.

METHODS

This prospective study was based on the Malmö Diet and Cancer Cohort. A total of 4688 participants (39.7% men; mean age, 57.6 years) were examined and blood samples were collected between 1991 and 1994. Incidence of stroke was followed up to 2018. Cox' proportional hazards regression was used to assess the relationship between VIM and stroke.

RESULTS

During a mean follow-up of 22.0 years, a total of 528 subjects were diagnosed with stroke, among which 434 were ischemic stroke. Participants in the highest quartile (vs 1^st quartile) had 1.34× higher risk of total stroke (95% CI, 1.03-1.74) and 1.47× higher of ischemic stroke (95% CI, 1.10-1.98) after adjustment for potential confounders. A significant interaction was found between carotid plaque and VIM with respect to incidence of both total stroke and ischemic stroke (P=0.041 and 0.011, respectively). After stratifying by carotid plaque, high VIM had stronger association with stroke in participants with carotid plaque, especially for the risk of ischemic stroke (adjusted hazard ratio,1.66 [95% CI, 1.23-2.25] for quartile 4 versus quartile 1 to 3).

CONCLUSIONS

VIM is positively associated with the incidence of stroke, especially in individuals with carotid plaque. Further studies are needed to confirm the observed associations.

Evaluation of autoantibodies against vimentin and α-enolase in rheumatoid arthritis patients

Introduction

Rheumatoid arthritis (RA) is categorized as an autoimmune disease with a frequency of 0.2–1% worldwide. It is reported that various autoantibodies are produced in the RA population, particularly against citrullinated peptides. Among various candidate markers for RA diagnosis, the citrullinated proteins have the highest specificity and sensitivity for both diagnosis and prognosis of RA. Anti-mutated citrullinated vimentin and α-enolase constitute a new class of autoantibodies for early detection of RA.

Material and methods

45 serum samples and 19 synovial fluid (SF) specimens collected from RA patients were considered for American College of Rheumatology criteria and 20 serum samples and 10 SF specimens were provided from healthy subjects as a control group. To assess the quantity of anti-citrullinated protein antibodies (ACPA), anti-mutated citrullinated vimentin (MCV) and anti-α-enolase in the serum and SF of RA patients were determined by the enzyme-linked immunosorbent assay (ELISA) method. For the evaluation of disease activity and joint destruction, we used the Disease Activity Score of 28 joints based on erythrocyte sedimentation rate (ESR) Disease Activity Score 28 (DAS28). Furthermore, to measure the molecular weight of vimentin and α-enolase, electrophoresis on 10% SDS-PAGE was performed as described before.

Results

The anti-α-enolase level among serum samples from RA patients was significantly higher than in healthy subjects (4.49 ±0.20 ng/ml vs. 0.76 ±0.12 ng/ml) (p < 0.001). There was a direct relation between α-enolase quantity and (rheumatoid factor) RF and C-reactive protein (CRP) levels. The mean ESR value in positive and negative ACPA patients was 38.2 ±22.6 mm/h and 9.2 ±5.8 mm/h respectively (p < 0.0001). The mean DAS28-ESR was 3.3. The level of anti-MCV in the serum of RA patients (244.6 ±53.3 U/ml) was higher than in serum of the healthy group (148.73 ±71.8) (p < 0.0001). The level of anti-MCV in the SF of patients was 687.5 ±148.4 U/ml.

Conclusions

In conclusion, both autoantibodies against MCV and α-enolase are two important markers that increase in serum and SF of RA patients and are specific for diagnosis of RA disease.

An Overview of the Intrinsic Role of Citrullination in Autoimmune Disorders

A protein undergoes many types of posttranslation modification. Citrullination is one of these modifications, where an arginine amino acid is converted to a citrulline amino acid. This process depends on catalytic enzymes such as peptidylarginine deiminase enzymes (PADs). This modification leads to a charge shift, which affects the protein structure, protein-protein interactions, and hydrogen bond formation, and it may cause protein denaturation. The irreversible citrullination reaction is not limited to a specific protein, cell, or tissue. It can target a wide range of proteins in the cell membrane, cytoplasm, nucleus, and mitochondria. Citrullination is a normal reaction during cell death. Apoptosis is normally accompanied with a clearance process via scavenger cells. A defect in the clearance system either in terms of efficiency or capacity may occur due to massive cell death, which may result in the accumulation and leakage of PAD enzymes and the citrullinated peptide from the necrotized cell which could be recognized by the immune system, where the immunological tolerance will be avoided and the autoimmune disorders will be subsequently triggered. The induction of autoimmune responses, autoantibody production, and cytokines involved in the major autoimmune diseases will be discussed.

Meta-analysis: compared with anti-CCP and rheumatoid factor, could anti-MCV be the next biomarker in the rheumatoid arthritis classification criteria?

Background

Previous reviews of the diagnosis for rheumatoid arthritis (RA) have not compared anti-mutated citrullinated vimentin (MCV) with anti-cyclic citrullinated peptide (CCP) and rheumatoid factor (RF) in respect of sensitivity, specificity and the area under the curve (AUC) against disease controls for differential diagnosis. This meta-analysis aims to evaluate the value of anti-MCV in the diagnosis for RA, the combined sensitivity of anti-MCV and anti-CCP, and certain clinical characteristics related to the performance of anti-MCV.

Methods

Medline, Embase, Cochrane Library and Web of Science were searched for articles published up to 25 August 2018. A total of 33 studies including 6044 RA patients and 5094 healthy or disease controls achieved inclusive criteria. QUADAS-2 was applied to evaluate the quality of the included studies. The bivariate random effects model was employed in primary data synthesis to evaluate the diagnostic performance.

Results

The sensitivity of anti-MCV, anti-CCP and RF in RA diagnosis against a disease control group was 0.71, 0.71, 0.77, with the specificity of 0.89, 0.95, 0.73, and the AUC of the SROC of 0.89, 0.95, 0.82, respectively. The predesign of the primary study and diagnostic criteria were statistically significant as sources of heterogeneity. Anti-MCV and anti-CCP tests demonstrated a sensitivity of 0.77 when performed in parallel, with a sensitivity of 0.60 when performed in series; whereas, the combination of anti-MCV and RF presented a sensitivity of 0.64 when used in series.

Conclusions

Anti-MCV demonstrates comparable diagnostic value to anti-CCP and RF, thus it can be an effective diagnostic marker for RA and may be written into the next authoritative criteria.

Diagnostic accuracy of anti-MCV and anti-CCP antibodies in rheumatoid arthritis: A meta-analysis

OBJECTIVE

The purpose of this study was to compare the diagnostic performance of anti-mutated citrullinated vimentin (anti-MCV) and anti-cyclic citrullinated peptide (anti-CCP) antibodies in rheumatoid arthritis (RA).

METHODS

We searched the Medline, Embase, and Cochrane library databases and performed two meta-analyses on the diagnostic accuracy of anti-MCV and anti-CCP in patients with RA compared to healthy controls.

RESULTS

We identified 12 studies that included a total of 2003 RA patients and 831 healthy controls for the meta-analysis. The pooled sensitivity and specificity of anti-MCV were 68.6% [95% confidence interval (CI) 66.6-79.7] and 94.2% (95% CI 92.4-96.7) and those of anti-CCP were 61.7% (95% CI 59.5-63.8) and 97.1% (95% CI 96.7-98.1), respectively. Anti-MCV PLR, NLR, and DOR were 12.99 (95% CI 8.013-21.27), 0.297 (95% CI 0.238-0.369), and 47.78 (95% CI 28.59-79.84), and those for anti-CCP were 16.71 (95% CI 11.42-24.47), 0.378 (95% CI 0.325-0.439), and 54.20 (95% CI 31.65-92.82), respectively. The AUC of anti-MCV was 0.886, and its Q* index was 0.817, indicating modest accuracy, while the AUC of anti-CCP was 0.946, and its Q* index was 0.885. The sensitivity of anti-MCV was significantly higher than that of anti-CCP in the diagnosis of RA (difference 0.069, 95% CI 0.039-0.098, p < 0.0001), but the specificity of anti-MCV was lower than that of anti-CCP (difference -0.029, 95% CI -0.051 to -0.006, p = 0.012). The Q* index of anti-MCV was significantly lower than that of anti-CCP (difference -0.068, 95% CI -0.070 to -0.065, p < 0.0001).

CONCLUSION

Our meta-analysis demonstrates that anti-MCV is more sensitive but less specific, and has lower diagnostic accuracy than anti-CCP in RA, although anti-MCV and anti-CCP showed comparable high PLRs.

A new look at rheumatology in China--opportunities and challenges

In the past two decades, Chinese rheumatology has developed rapidly in terms of both clinical practice and basic research. Many rheumatology departments and divisions have been established, creating positions for more residents to join rheumatology practices. Numerous studies of rheumatic diseases have been published in recent years by Chinese rheumatologists and immunologists, supported by government funding that has dramatically increased over the past few years. These studies are focused mainly on epidemiology, mechanisms, early diagnosis and interventions of rheumatic diseases. Increasing numbers of national and international scientific activities in China, including research collaborations, education programmes and conferences have greatly helped the development of rheumatology. In this APLAR series article, the major, high-impact studies and latest developments in Chinese rheumatology are reviewed.

Role of protein phosphatase magnesium-dependent 1A and anti-protein phosphatase magnesium-dependent 1A autoantibodies in ankylosing spondylitis

OBJECTIVE

Although ankylosing spondylitis (AS) is driven by immune-mediated processes, little is known about the presence and role of autoantibodies in this disease. This study was undertaken to investigate whether autoantibodies occur in and are involved in AS.

METHODS

We performed human protein microarray analysis of sera derived from patients with AS or other autoimmune disorders to identify autoantibodies associated specifically with AS, and identified autoantibody targeting of protein phosphatase magnesium-dependent 1A (PPM1A) in AS. We performed enzyme-linked immunosorbent assay (ELISA) analysis of sera from 2 independent AS cohorts to confirm autoantibody targeting of PPM1A, and to assess associations between levels of anti-PPM1A antibodies and AS disease severity or response to anti-tumor necrosis factor (anti-TNF) therapy (as measured by Bath AS Disease Activity Index [BASDAI] score). Levels of anti-PPM1A antibodies were also evaluated in sera from rats transgenic for HLA-B27 and human β2 -microglobulin. The expression of PPM1A was assessed by immunohistochemistry in synovial tissue samples from patients with AS, rheumatoid arthritis, or osteoarthritis. The role of PPM1A in osteoblast differentiation was investigated by gene knockdown and overexpression.

RESULTS

AS was associated with autoantibody targeting of PPM1A, and levels of anti-PPM1A autoantibodies were significantly higher in patients with more advanced sacroiliitis and correlated positively with BASDAI score after treatment with anti-TNF agents. The levels of anti-PPM1A autoantibodies were also higher in the sera of transgenic rats that are prone to develop spondyloarthritis than in those that are not. PPM1A was expressed in AS synovial tissue, and PPM1A overexpression promoted osteoblast differentiation, whereas PPM1A knockdown suppressed it.

CONCLUSION

Anti-PPM1A autoantibodies are present in AS, and our findings suggest that PPM1A may contribute to the pathogenic bone ankylosis characteristic of AS.

Clinical biomarkers and pathogenic-related cytokines in rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune disease with unknown etiology and pathogenesis. Although major therapeutic advances have been made in recent years, there is no cure for the disease. Current medications mainly reduce inflammation in order to relieve pain and slow joint damage, but many have potentially serious side effects. Therefore, to find specific biomarkers will benefit both RA patients to find relief from the disease and physicians to monitor the disease development. A number of biomarkers have been discovered and used clinically, and others are still under investigation. The autoantibodies, which are widely used in diagnosis and prognosis, novel biomarkers, which reflect clinical disease activity, and newly found biomarkers and pathogenic-related cytokines are discussed in this review.

Comparison of two assays to determine anti-citrullinated peptide antibodies in rheumatoid arthritis in relation to other chronic inflammatory rheumatic diseases: assaying anti-modified citrullinated vimentin antibodies adds value to second-generation anti-citrullinated cyclic peptides testing

Determination of anti-citrullinated peptide antibodies (ACPA) plays a relevant role in the diagnosis of rheumatoid arthritis (RA). To date, it is still unclear if the use of several tests for these autoantibodies in the same patient offers additional value as compared to performing only one test. Therefore, we evaluated the performance of using two assays for ACPA: second-generation anti-citrullinated cyclic peptides antibodies (anti-CCP2) and anti-mutated citrullinated vimentin (anti-MCV) antibodies for the diagnosis of RA. We compared three groups: RA (n = 142), chronic inflammatory disease (CIRD, n = 86), and clinically healthy subjects (CHS, n = 56) to evaluate sensitivity, specificity, predictive values, and likelihood ratios (LR) of these two assays for the presence of RA. A lower frequency of positivity for anti-CCP2 was found in RA (66.2%) as compared with anti-MCV (81.0%). When comparing RA versus other CIRD, sensitivity increased when both assays were performed. This strategy of testing both assays had high specificity and LR+. We conclude that adding the assay of anti-MCV antibodies to the determination of anti-CCP2 increases the sensitivity for detecting seropositive RA. Therefore, we propose the use of both assays in the initial screening of RA in longitudinal studies, including early onset of undifferentiated arthritis.

Relatives without rheumatoid arthritis show reactivity to anti-citrullinated protein/peptide antibodies that are associated with arthritis-related traits: studies of the etiology of rheumatoid arthritis

OBJECTIVE

To examine reactivity to anti-citrullinated protein/peptide antibodies (ACPAs) and determine associations between ACPAs and other rheumatoid arthritis (RA)-related autoantibodies and clinically assessed swollen or tender joints in unaffected first-degree relatives of RA patients.

METHODS

Serum samples were obtained from first-degree relatives without RA according to the 1987 American College of Rheumatology (ACR) and the 2010 ACR/European League Against Rheumatism classification criteria. A bead-based assay was used to measure 16 separate ACPAs in sera from 111 antibody-positive first-degree relatives who were positive on at least 1 visit for any of 5 RA-related autoantibodies (rheumatoid factor [RF], anti-cyclic citrullinated peptide 2 [anti-CCP-2], and RF isotypes), and sera from 99 antibody-negative first-degree relatives who were never autoantibody positive. Cutoffs for positivity for each ACPA were determined using receiver operating characteristic curves derived from data on 200 RA patients and 98 blood donor controls, in which positivity for ≥9 ACPAs had 92% specificity and 62% sensitivity for RA. In first-degree relatives, ACPA reactivity was assessed, and associations between ACPAs (number positive, and positivity for ≥9 ACPAs) and RA-related characteristics were examined.

RESULTS

Fifty-seven percent of anti-CCP-2-positive first-degree relatives and 8% of anti-CCP-2- negative first-degree relatives were positive for ≥9 ACPAs. After adjusting for age, sex, ethnicity, and pack-years of smoking, an increasing number of ACPAs was directly associated with the presence of ≥1 tender joint on examination (odds ratio [OR] 1.18, 95% confidence interval [95% CI] 1.04-1.34), with the greatest risk of having ≥1 tender joint seen in first-degree relatives positive for ≥9 ACPAs (OR 5.00, 95% CI 1.37-18.18).

CONCLUSION

RA-free first-degree relatives (even those negative for RF and anti-CCP-2) demonstrate reactivity to multiple ACPAs, and the presence of an increasing number of ACPAs may be associated with signs of joint inflammation. Prospective evaluation of the relationship between these findings and the progression of classifiable RA is warranted.

Serum levels of calreticulin in correlation with disease activity in patients with rheumatoid arthritis

OBJECTIVE

The aim of our study was to investigate the contribution of serum calreticulin (CRT) in the assessment of disease activity in rheumatoid arthritis (RA).

METHODS

Serum CRT levels were measured by ELISA in 70 patients with established RA, 30 systemic lupus erythematosus (SLE), 25 other autoimmune diseases, 20 osteoarthritis (OA), and 35 of healthy controls (HC). Correlations of CRT serum levels with disease activity [Disease Activity Score for 28 joints (DAS28)], erythrocyte sedimentation rate(ESR) and C-reactive protein (CRP) were assessed. Serum CRT levels were also detected in RA patients whose RF, anti-CCP and anti- MCV antibodies were positive and negative.

RESULTS

Serum CRT levels in RA patients (4.817 ± 2.425 ng/ml) was significantly higher (P <0.05) compared with those in the serum of OA (3.574 ± 0.942 ng/ml), SLE (4.013 ± 1.536 ng/ml), other autoimmune diseases (3.882 ± 0.837 ng/ml) and HC (3.726 ± 0.627 ng/ml). Significant positive correlation of CRT with DAS28, ESR and CRP was found in RA patients. Furthermore, RA patients whose anti-CCP and anti-MCV antibodies were positive had higher levels of CRT (P < 0.01).

CONCLUSION

Serum CRT levels were increased in patients with RA compared with those controls. Moreover, a significant correlation was observed between serum CRT levels and disease activity in RA. It might be used as a potential biomarker for clinical diagnosis and provide additional information regarding disease activity along with the traditional indices such as ESR and CRP.

Evaluation of anti-mutated citrullinated vimentin antibodies, anti-cyclic citrullinated Peptide antibodies and rheumatoid factor in omani patients with rheumatoid arthritis

Rheumatoid factor (RF) is currently used in the diagnosis of rheumatoid arthritis (RA). The discovery of anticitrullinated protein autoantibodies has led to the development of various new tests, such as anti-cyclic citrullinated peptide (anti-CCP) antibodies, and anti-mutated citrullinated vimentin (anti-MCV) antibodies, to diagnose RA. The aims of this study were to determine the sensitivity and specificity of anti-MCV antibodies in comparison with anti-CCP antibodies and RF in Omani Arab patients with RA and compare our findings with published values from different ethnic groups. The sensitivity of anti-MCV antibodies was 72% with 87% specificity. For anti-CCP antibodies the sensitivity was 52% and the specificity was 97%. The sensitivity of RF was 57% with 94% specificity. Anti-CCP antibodies have higher diagnostic specificity and positive predictive value than RF and anti-MCV antibodies. Anti-MCV antibodies have the highest sensitivity when compared to anti-CCP antibodies and RF. Anti-MCV antibodies do not appear to be very useful in the diagnosis of RA. However, long-term study is required to find out whether anti-MCV antibodies can be used as predictive test for incidence of RA.

The reporting quality of studies investigating the diagnostic accuracy of anti-CCP antibody in rheumatoid arthritis and its impact on diagnostic estimates

BACKGROUND

Recently anti-CCP testing has become popular in the diagnosis of rheumatoid arthritis (RA). However, the inadequate reporting of the relevant diagnostic studies may overestimate and bias the results, directing scientists into making false decisions. The aim of the present study was to evaluate the reporting quality of studies used anti-CCP2 for the diagnosis of RA and to explore the impact of reporting quality on pooled estimates of diagnostic measures.

METHODS

PubMed was searched for clinical studies investigated the diagnostic accuracy of anti-CCP. The studies were evaluated for their reporting quality according to STARD statement. The overall reporting quality and the differences between high and low quality studies were explored. The effect of reporting quality on pooled estimates of diagnostic accuracy was also examined.

RESULTS

The overall reporting quality was relatively good but there are some essential methodological aspects of the studies that are seldom reported making the assessment of study validity difficult. Comparing the quality of reporting in high versus low quality articles, significant differences were seen in a relatively large number of methodological items. Overall, the STARD score (high/low) has no effect on the pooled sensitivities and specificities. However, the reporting of specific STARD items (e.g. reporting sufficiently the methods used in calculating the measures of diagnostic accuracy and reporting of demographic and clinical characteristics/features of the study population) has an effect on sensitivity and specificity.

CONCLUSIONS

The reporting quality of the diagnostic studies needs further improvement since the study quality may bias the estimates of diagnostic accuracy.

Anti-microtubule organizing center with microtubule by autoimmune target test is also useful serological marker in rheumatoid arthritis evaluation

Seropositivity of rheumatoid factor (RF) or anti-cyclic citrullinated peptide antibody (anti-CCP) is one domain of scoring system in new American College of Rheumatology/European League against Rheumatism classification criteria for rheumatoid arthritis (RA). We investigated usefulness of antiperinuclear factor (APF) and autoantibody to microtubule organizing center with microtubule (anti-MTOC-MT), which was detected by autoimmune target (AIT) test, as serological markers for the diagnosis of early RA. The test results of 3,503 patients from the outpatient clinic of The Hospital for Rheumatic Diseases who underwent test for RF, APF, anti-CCP and anti-MTOC-MT simultaneously for the work-up of RA were analyzed. Four kinds of tests showed same results only in 53.1% (1,861/3,503) of all subjects. The kappa coefficient between each test was distributed from -0.011 to 0.622. The agreement was best between RF and anti-CCP (kappa coefficient: 0.622), but the agreement was poor between anti-MTOC-MT and other 3 tests (kappa coefficient: 0.007 to -0.025). In both of RF- and anti-CCP-negative patients, the patients who showed positive result for APF were 4.6% (160/3,503) and for anti-MTOC-MT were 13.2% (464/3,503). RF and anti-CCP positivity could not include all of APF and anti-MTOC-MT positivity. Anti-MTOC-MT detected by AIT test was independent serological marker, and it might be also helpful for the diagnosis of early RA. Therefore, the combined detection of all four serologic markers can be useful for the evaluation of suspected RA patients.

Mutated citrullinated vimentin antibodies in rheumatoid arthritis

Rheumatoid arthritis (RA) is the most common inflammatory systemic autoimmune disease, primarily affecting the peripheral joints. The past decade has been marked with revolutionary changes both in the therapeutic and diagnostic perspectives of RA. The discovery of an RA-specific citrullination-driven immune reaction gave a substantial contribution in the diagnostic approach to RA. Efforts directed towards the identification of the antigenic target specifically recognized by these autoantibodies resulted in the identification of vimentin in citrullinated form as the potential native antigen, among other proteins. Furthermore, it was found that the mutation of vimentin represents an independent trigger of antigenic properties, in addition to citrullination. As a result of this discovery, a commercial ELISA using mutated citrullinated vimentin (MCV) was developed. Increasingly, data now support the use of anti-MCV in RA diagnosis and prognosis for errosion. This review summarizes the research to date on the use of anti-MCV in RA diagnosis and prognosis and its potential use as a therapeutic marker. The pathologic role of these antibodies in RA disease is also discussed.

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.

Association of anti-modified citrullinated vimentin with subclinical atherosclerosis in early rheumatoid arthritis compared with anti-cyclic citrullinated peptide

OBJECTIVE

To investigate anti-modified citrullinated vimentin (anti-MCV) in early rheumatoid arthritis (RA), including correlation with disease activity and cardiovascular risk factors, compared with anti-cyclic citrullinated peptides (anti-CCP3).

METHODS

Anti-MCV and anti-CCP3 concentrations were measured in 100 patients with early RA and 100 healthy controls at baseline to determine sensitivity and specificity. Patients received methotrexate (MTX) 0.2 mg/kg/week plus prednisone 10 mg/day. Anti-MCV, anti-CCP3, rheumatoid factor (RF), Disease Activity Score for 28 joints (DAS-28), lipid profile, erythrocyte sedimentation rate (ESR), high-sensitivity C-reactive protein assay (hsCRP), homeostasis model assessment for insulin resistance (HOMA-IR) index, tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and carotid intima-media thickness (cIMT) were measured before and after 12 months of treatment.

RESULTS

The sensitivity and specificity for anti-MCV antibody were 75% and 90%, respectively, and for anti-CCP3 antibody 71% and 96%. Serum anti-MCV and serum anti-CCP3 levels at baseline were positively correlated with hsCRP, IL-6, HOMA-IR index, serum RF levels (p < 0.001), and cIMT (p < 0.05). Serum anti-MCV was positively correlated with serum anti-CCP3 levels. There were significant positive correlations between the percentage of changes of anti-MCV levels versus changes in DAS-28, ESR, hsCRP, atherogenic ratios (TC/HDL-C and LDL-C/HDL-C), apolipoprotein A-I, IL-6, TNF-α, HOMA-IR index, and cIMT. These correlations were not found between changes in anti-CCP3 levels compared to clinical, laboratory, and radiological variables.

CONCLUSION

Anti-MCV was as sensitive as anti-CCP3 in diagnosing early RA. Anti-MCV testing appears to be useful for monitoring associated subclinical atherosclerosis in early RA.

The relevance of citrullinated vimentin in the production of antibodies against citrullinated proteins and the pathogenesis of rheumatoid arthritis

Antibodies against citrullinated proteins (ACPAs) are highly specific for RA. Since the discovery of these antibodies, several of studies that focused on the presence and identity of citrullinated proteins in the joints of RA patients have been carried out. The best-known antigens that bind ACPAs are citrullinated filaggrin, Type II collagen (CII), α-enolase, fibrinogen and vimentin. This review compares citrullinated filaggrin, CII, α-enolase and fibrinogen with vimentin in their contribution to ACPA triggering, and gives an overview of the literature in which the role of citrullinated and non-citrullinated vimentin in the onset of ACPA production and the pathogenesis of RA is discussed.

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.

Growing Trend of China’s Contribution to the Field of Rheumatology 2000–2009: A Survey of Chinese Rheumatology Research

Objective.

In the past decade, rheumatology in China has achieved great advances. However, scientific publications on rheumatology in the 3 major regions of China — Mainland (ML), Hong Kong (HK), and Taiwan (TW) — are unknown. We assessed the performance of rheumatology research in China from 2000 to 2009.

Methods.

Twenty-two journals included in the rheumatology category of the Journal Citation Reports database were selected. We analyzed the following measures for 2000–2009: (1) total number of articles originating from ML, HK, and TW; (2) impact factor (IF) of those articles; (3) total number of citations and average number of citations per article; and (4) number of articles about clinical trials, randomized controlled trials (RCT), and case reports. We also noted the total number of articles from the 3 regions published in 10 top-ranking journals.

Results.

There were 788 articles for the 3 regions of China, including 259 from ML, 372 from TW, and 157 from HK, with a positive trend between the years 2000 to 2009. From 2006 on, published articles from ML exceeded those from HK, and in 2008, published articles from ML exceeded those from TW. HK had the highest average IF and highest average citations of each article compared with articles from ML and TW. TW published the most RCT, clinical trials, and case reports, as well as the most articles in the 10 top-ranking journals in the last decade, followed by ML and HK.

Conclusion.

Chinese contributions to the field of rheumatology have increased rapidly since 2000, particularly from ML. HK had the highest quality research output according to average IF and average citations per article.

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.