Antiphospholipid antibodies and atherosclerosis: Insights from Rheumatoid arthritis – A five-year follow-up study

Cardiovascular Risk Assessment in Rheumatoid Arthritis: Accelerated Atherosclerosis, New Biomarkers, and the Effects of Biological Therapy

Rheumatoid arthritis (RA), one of the most common of the chronic inflammatory autoimmune diseases (CIADs), is recognized as an independent cardiovascular risk factor. Traditional risk factors such as smoking, arterial hypertension, dyslipidemia, insulin resistance, and obesity are frequently found in RA. Given the increased risk of mortality and morbidity associated with cardiovascular disease (CVD) in RA patients, screening for risk factors is important. Moreover, there is a need to identify potential predictors of subclinical atherosclerosis. Recent studies have shown that markers such as serum homocysteine, asymmetric dimethylarginine, or carotid intima-media thickness (cIMT) are correlated with cardiovascular risk. Although RA presents a cardiovascular risk comparable to that of diabetes, it is not managed as well in terms of acute cardiovascular events. The introduction of biological therapy has opened new perspectives in the understanding of this pathology, confirming the involvement and importance of the inflammatory markers, cytokines, and the immune system. In addition to effects in inducing remission and slowing disease progression, most biologics have demonstrated efficacy in reducing the risk of major cardiovascular events. Some studies have also been conducted in patients without RA, with similar results. However, early detection of atherosclerosis and the use of targeted therapies are the cornerstone for reducing cardiovascular risk in RA patients.

Accelerated atherosclerosis in premenopausal women with rheumatoid arthritis - 15-year follow-up

Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with increased mortality and morbidity due to the higher cardiovascular risk in these patients. Traditional risk factors are not the only answer for the accelerated atherosclerosis. In a long-term prospective study, we investigated the relationship between asymptomatic atherosclerosis and traditional risk factors and inflammatory markers in patients with RA and matched healthy controls. We studied the laboratory test results, the concentrations of inflammatory mediators, matrix metalloproteases (MMP), and inflammation markers in a total of 70 (60 at follow-up) premenopausal healthy women with RA and 40 (34 at follow-up) matched controls. We used the B-mode ultrasound imaging of carotid arteries for the detection of asymptomatic atherosclerosis. Correlation with different factors was evaluated. Statistically significant higher values of inflammatory markers such as selective adhesion molecules ICAM and VCAM, interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and MMP-3 in the patients group were found in the follow-up study. More plaques were found in the patients group (42.4% vs. 12.9%; p=0.005), as compared with the controls group. The patients had also higher values of cIMT (p=0.001). Using bivariate regression analysis only VCAM was found as a prognostic factor for plaque occurrence (r= 0. 341, p=0.016), but not for cIMT (r= -0.130, p=0.327) in premenopausal female patients with RA after the follow-up. Therefore, asymptomatic atherosclerosis is accelerated in premenopausal women with RA. The results of our follow-up study showed the association between inflammation and accelerated atherosclerosis. Furthermore, VCAM was found to have a statistically significant correlation with plaque occurrence in these patients.

Beta-2-glycoprotein-I IgA antibodies predict coronary plaque progression in rheumatoid arthritis

OBJECTIVES

To evaluate whether anti-Beta-2-Glycoprotein-I (anti-β2GPI) IgA antibodies associate with progression of coronary atherosclerosis and cardiovascular disease (CVD) events in rheumatoid arthritis (RA).

METHODS

One hundred-fifty patients underwent plaque evaluation (total, non-calcified, mixed and calcified) with coronary computed tomography angiography; 101 were re-imaged within 6.9±0.3 years to assess progression. The Framingham-D'Agostino score assessed cardiovascular risk. Coronary artery calcium (CAC) and segment involvement score quantified plaque burden.

RESULTS

Anti-β2GPI IgA were seen in 45 (30%) patients. Despite no link to baseline plaque burden, anti-β2GPI IgA associated with segment involvement score increase (adjusted-RR=1.64 [95%CI 1.02-2.63]), CAC change (adjusted-β=0.33 [95%CI 0.002-0.656]) and developing new extensive or obstructive plaque at follow-up (adjusted-OR=4.24 [95%CI 1.30-13.87]). Adding anti-β2GPI IgA to logistic regression models with conventional risk factors predicting plaque progression outcomes increased Area under the receiver-operator curve and improved Net Reclassification and Integrated Discrimination Improvement indices (all P<0.05). In per-segment analyses, anti-β2GPI IgA predicted mixed plaque formation (adjusted-OR=3.20 [95%CI 1.01-10.09]) and lower likelihood of transition of mixed to calcified plaque (adjusted-OR=0.19 [95%CI 0.04-0.96]). Anti-β2GPI IgA moderated the effect of C-reactive protein on CAC change such that C-reactive protein associated with CAC change (β=0.26 [95%CI 0.14-0.38]) and CVD risk (adjusted-HR=1.89 [95%CI 1.02-3.51]) only in anti-β2GPI IgA positive patients.

CONCLUSION

Anti-β2GPI IgA addition to clinical risk models improved prediction accuracy of CAC, plaque progression and transition to extensive/obstructive disease. They associated with new high-risk mixed plaques and delayed healing to calcified lesions. Anti-β2GPI IgA further modified the effect of inflammation on plaque progression and CVD events.

Immunoglobulin A Isotype of Antiphospholipid Antibodies Does Not Provide Added Value for the Diagnosis of Antiphospholipid Syndrome in a Chinese Population

Objective

Antiphospholipid syndrome (APS) is characterized by the presence of anti-phospholipid (aPL) antibodies. However, the relationship between the immunoglobulin (Ig) A isotype of aPL positivity and its clinical utility in APS diagnosis is controversial. Presently, we determine the clinical utility of IgA-aPL from consecutive patients in a large cohort from the Chinese population and patients with APS whose aPL profiles were obtained.

Methods

The detection of anticardiolipin (aCL) and anti-β₂ glycoprotein-Ⅰ (aβ₂GPⅠ) antibodies of the IgA/IgG/IgM isotype by paramagnetic particle chemiluminescent immunoassay was carried out in sera from 7293 subjects. 153 primary APS (PAPS) patients and 59 patients with secondary APS (SAPS) were included in this study.

Results

In total, 1,082 out of 7,293 (2.55%) subjects had a positive IgA-aPL test, and the prevalence of isolated IgA-aPL was 0.29% (21/7,293) in the general population. The prevalence of IgA-aPL in the PAPS patients was 12.42% (19/153); however, only one patient (0.65%) presented with isolated IgA-aPL. Fifty (25.9%) of the SAPS had IgA-aPL, none of whom lacked IgG/IgM-aPL. The combination of the IgA isotype and the IgG/IgM isotype did not increase the diagnostic performance when compared with the IgG/IgM isotype of aCL or aβ₂GPⅠ, respectively. IgA-aPL was not associated with clinical manifestation in patients with APS.

Conclusion

Isolated IgA-aPL is rare in the general population as well as in patients with APS. Whether in the laboratory or in clinical practice, the presence of IgA-aPL does not provide added value for the diagnosis of APS in the Chinese population.

Association between antiphospholipid antibodies and arterial thrombosis in patients with rheumatoid arthritis

OBJECTIVES

Antiphospholipid antibodies (aPL) are present in a proportion of patients with rheumatoid arthritis but their clinical significance remains unclear. We investigated the association between aPL and thrombotic events in rheumatoid arthritis patients.

METHODS

In this cross-sectional study, aPL profiles were evaluated in 376 rheumatoid arthritis patients in accordance with the standard guidelines. Clinical and radiographic data were retrospectively collected.

RESULTS

aPL were identified in 39 patients (10.4%). Lupus anticoagulant was the most common subtype (n = 25, 6.6%); anti-cardiolipin antibodies and anti-β₂ glycoprotein I antibodies were detected in six and 12 patients (1.6% and 3.2%), respectively. Compared to the aPL-negative group, aPL-positive patients included more male patients (41.0% vs. 15.4%, P < 0.001) and more smokers (41.0% vs. 16.0%, P = 0.001). There was no difference between the two groups in age, disease duration and body mass index, or the frequency of diabetes, hypertension or dyslipidaemia. Of note, arterial thromboses were more common in the aPL-positive than the aPL-negative group (12.8% vs. 2.1%, P = 0.004), whereas the frequency of venous thrombosis did not differ between the two groups (0.0% vs. 0.9%, P = 1.000). On multivariate regression analysis, aPL, age, hypertension, dyslipidaemia and baseline C-reactive protein level were independently associated with arterial thrombotic events (all P values < 0.05).

CONCLUSION

aPL was found in a subset of rheumatoid arthritis patients, who were more often smokers, and aPL was independently associated with development of arterial thrombosis. This result suggests that aPL may contribute to an increased risk of arterial thrombosis in rheumatoid arthritis patients.

Increased carotid intima-media thickness in rheumatoid arthritis: an update meta-analysis

This study aims to derive a more precise estimation on carotid intima-media thickness (CIMT) level in patients with rheumatoid arthritis (RA) and related factors. Studies published from January 1, 1982 to December 31, 2014 in English, which comparing CIMT between RA group and control group were searched in PubMed, Embase, and Cochrane Library databases. Heterogeneity test was performed, and publication bias was evaluated. Stata software 12.0 was used to perform the meta-analysis. Two-thousand one hundred sixty-three articles were obtained after searching databases, and 47 studies were finally included in the meta-analysis. The result of the analysis in random effect model showed that RA group had significantly higher CIMT than control group, with the standardized mean difference (SMD) of 1.04 and 95% CI (0.81,1.27). To evaluate the stability of our results, sensitivity analyses were performed, and the results showed no significant change when any one study was excluded. Subgroup analyses showed that region, race, age, BMI, and disease duration were associated with CIMT in RA patients. In summary, CIMT in RA patients is thicker than healthy controls, and it is influenced by region, race, age, BMI, and disease duration.

Therapeutic potential of folic acid supplementation for cardiovascular disease prevention through homocysteine lowering and blockade in rheumatoid arthritis patients

Rheumatoid arthritis (RA) is a chronic inflammatory disease that preferentially affects joints, and characterized by an approximately two-fold increased risk of cardiovascular diseases compared with the general population. Beyond classical cardiovascular risk factors, systemic inflammatory markers are primarily involved. Hence, anti-inflammatory strategies such as homocysteine-lowering interventions are warranted. Indeed, hyperhomocysteinemia is commonly found in RA patients as a result of both genetic and non-genetic factors including older age, male gender, disease-specific features and disease-modifying antirheumatic drugs. Most importantly in the pathophysiology of hyperhomocysteinemia and its related cardiovascular diseases in RA, there is a bi-directional link between immuno-inflammatory activation and hyperhomocysteinemia. As such, chronic immune activation causes B vitamins (including folic acid) depletion and subsequent hyperhomocysteinemia. In turn, hyperhomocysteinemia may perpetrate immuno-inflammatory stimulation via nuclear factor ƙappa B enhancement. This chronic immune activation is a key determinant of hyperhomocysteinemia-related cardiovascular diseases in RA patients. Folate, a homocysteine-lowering therapy could prove valuable for cardiovascular disease prevention in RA patients in the near future with respect to homocysteine reduction along with blockade of subsequent oxidative stress, lipid peroxidation, and endothelial dysfunction. Thus, large scale and long term homocysteine-lowering clinical trials would be helpful to clarify the association between hyperhomocysteinemia and cardiovascular diseases in RA patients and to definitely state conditions surrounding folic acid supplementation. This article reviews direct and indirect evidence for cardiovascular disease prevention with folic acid supplementation in RA patients.

Clinical significance of IgA anti-cardiolipin and IgA anti-β2glycoprotein I antibodies

IgA antiphospholipid antibodies (aPL) are not currently recognized as formal laboratory criteria for the Antiphospholipid Syndrome (APS). This is mainly due to methodological issues (different study designs, use of various non-standardized IgA assays). However, there are experimental data showing the pathogenic role of IgA anti-cardiolipin antibodies (aCL) and IgA anti-β2glycoprotein I antibodies (anti-β2GPI). Isolated IgA aCL are not very common, therefore their testing could be useful in the case of strong suspicion of APS but negative results for other aPL tests. IgA anti-β2GPI seem to be the most prevalent isotype in patients with Systemic Lupus Erythematosus (SLE), with a significant association with thrombotic events. Such a clinical relevance has been recently recognized by the inclusion of these autoantibodies among the aPL tests in the novel SLICC classification criteria for SLE. Emerging interest has been raised by IgA anti-β2GPI against domain 4/5 as a novel subgroup of clinically relevant aPL.

Evidence on the pathogenic role of auto-antibodies in acute cardiovascular diseases

Atherothrombosis is the major determinant of acute ischaemic cardiovascular events, such as myocardial infarction and stroke. Inflammatory processes have been linked to all phases of atherogenesis In particular, the identification of autoimmunity mediators in the complex microenvironment of chronic inflammation has become the focus of attention in both early and advanced atherogenic processes. Auto-antibodies against self-molecules or new epitopes generated by oxidative processes infiltrate atherosclerotic plaques and were shown to modulate the activity of immune cells by binding various types of receptors. However, despite mounting evidence for a pathophysiological role of autoantibodies in atherothrombosis, the clinical relevance for circulating autoantibodies in cardiovascular outcomes is still debated. This review aims at illustrating the mechanisms by which different types of autoantibodies might either promote or repress atherothrombosis and to discuss the clinical studies assessing the role of auto-antibodies as prognostic biomarkers of plaque vulnerability.

The clinical relevance of IgA anticardiolipin and IgA anti-β2 glycoprotein I antiphospholipid antibodies: a systematic review

The antiphospholipid syndrome (APS) is diagnosed in patients with thromboembolic events and/or pregnancy loss in the presence of persistent laboratory evidence for antiphospholipid antibodies (aPL). Diagnostic tests for the detection of antiphospholipid antibodies include laboratory assays that detect anticardiolipin antibodies, lupus anticoagulants, and anti-β(2)-glycoprotein I antibodies. Most studies on aPL have mainly focused on the estimation of the IgG and IgM isotypes, with only a few studies reporting on the pathogenic significance of IgA aPL. In this review we aimed to summarize and analyze the evidence published in the literature on the prevalence and the clinical significance of IgA aPL.