Independent association of anti-beta(2)-glycoprotein I antibodies with macrovascular disease and mortality in scleroderma patients

Serum Biomarkers in Connective Tissue Disease-Associated Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a life-threatening complication of connective tissue diseases (CTDs) characterised by increased pulmonary arterial pressure and pulmonary vascular resistance. CTD-PAH is the result of a complex interplay among endothelial dysfunction and vascular remodelling, autoimmunity and inflammatory changes, ultimately leading to right heart dysfunction and failure. Due to the non-specific nature of the early symptoms and the lack of consensus on screening strategies-except for systemic sclerosis, with a yearly transthoracic echocardiography as recommended-CTD-PAH is often diagnosed at an advanced stage, when the pulmonary vessels are irreversibly damaged. According to the current guidelines, right heart catheterisation is the gold standard for the diagnosis of PAH; however, this technique is invasive, and may not be available in non-referral centres. Hence, there is a need for non-invasive tools to improve the early diagnosis and disease monitoring of CTD-PAH. Novel serum biomarkers may be an effective solution to this issue, as their detection is non-invasive, has a low cost and is reproducible. Our review aims to describe some of the most promising circulating biomarkers of CTD-PAH, classified according to their role in the pathophysiology of the disease.

Endothelial Dysfunction in Systemic Lupus Erythematosus and Systemic Sclerosis: A Common Trigger for Different Microvascular Diseases

This review describes the complex interplay between inflammation, vasculopathy and fibrosis that involve the heart and peripheral small vessels, leading to endothelial stiffness, vascular damage, and early aging in patients with systemic lupus erythematosus and systemic sclerosis, which represents two different models of vascular dysfunction among systemic autoimmune diseases. In fact, despite the fact that diagnostic methods and therapies have been significantly improved in the last years, affected patients show an excess of cardiovascular mortality if compared with the general population. In addition, we provide a complete overview on the new techniques which are used for the evaluation of endothelial dysfunction in a preclinical phase, which could represent a new approach in the assessment of cardiovascular risk in these patients.

Association between systemic sclerosis and peripheral arterial disease: a nationwide observation retrospective claim records cohort study in Taiwan

OBJECTIVES

Recent studies have proposed associations between systemic sclerosis (SSc) and atherosclerosis and between SSc and cardiovascular disease. However, in Asia, no large-scale studies have focused on the association between peripheral arterial disease (PAD) and SSc.

SETTING

A nationwide observation retrospective cohort study.

PARTICIPANTS

The National Health Insurance Research Database was used for selecting patients diagnosed with SSc from 2000 to 2011. Patients diagnosed with PAD before the index date were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

The SSc cohort comprised 1106 patients with SSc, and the non-SSc cohort comprised 4424 matched controls. The Cox proportional hazards regression model was used for analysing the adjusted risk of PAD between the case and control patients.

RESULTS

The SSc cohort exhibited a significantly higher risk (HR=2.15, 95% CI=1.47 to 3.14) of PAD than did the non-SSc cohort. Patients with heart failure exhibited the highest risk of PAD (adjusted HR=2.10, 95% CI=1.20 to 3.70). Moreover, even without any comorbidities, the SSc cohort exhibited a significantly higher risk (adjusted HR=4.17 fold, 95% CI=1.98 to 8.77) of PAD than did the non-SSc cohort.

CONCLUSION

SSc is associated with a significantly high risk of PAD. Further studies are required to reduce the PAD risk among patients with SSc.

Antiphospholipid Antibodies in Inflammatory and Autoimmune Rheumatic and Musculoskeletal Diseases Beyond Lupus: A Systematic Review of the Available Evidence

Background

The diagnosis of antiphospholipid syndrome (APS) requires the presence of thrombosis and/or recurrent miscarriages along with one or more anti-phospholipid antibodies (aPL). The role of aPL has been largely investigated in systemic lupus erythematosus (SLE) with minimal data on other autoimmune rheumatic diseases. In this review, we aim to assess the prevalence of aPL in patients with inflammatory and autoimmune rheumatic and musculoskeletal diseases (RMDs) other than SLE, and their association with thrombosis.

Results

A total of 20 studies, including 3242 patients, measured aPL in different inflammatory and autoimmune RMDs. The overall median percentage of aPL-positive patients was 14.05% (from 0 to 57.5%). For systemic sclerosis (SSc) patients, the median positivity was 14.05% for aPL, with IgG aCL being detected in up to 35.48% of all SSc aPL-positive patients. Only six studies (30%) performed an antibody confirmation test after 12 weeks, with the median prevalence being 10.88% (from 0 to 29.79%). Only six studies also assessed the number of double or triple aPL-positive patients. A total of eight (40%) studies including 1071 patients investigated the association between aPL and thrombotic events, namely five for SSc, one for SS, one for ANCA associated vasculitides (AAV), and one for RA. A median of 18.75% (7.69–71.43%) of aPL-positive patients experienced an arterial event in comparison to a median of 13.66% (7.69–31.25%) who underwent venous thrombotic event. Taking into consideration only the studies that performed a confirmation test, a median value of 34.36% (12.9–71.43%) of aPL-positive patients underwent an arterial event and a median value of 16.32% (9.68–25%) of aPL-positive patients underwent a venous event.

Conclusions

Anti-phospholipid antibodies can be detected in up to a third of patients with inflammatory and autoimmune RMDs, especially in SSc. However, there was a large heterogeneity among the retrieved studies. Available data supporting a general screening for aPL in all inflammatory and autoimmune RMDs are still insufficient. Screening for aPL in selected scenarios (e.g., pregnancy planning) could be considered.

The Weight of IgA Anti-β2glycoprotein I in the Antiphospholipid Syndrome Pathogenesis: Closing the Gap of Seronegative Antiphospholipid Syndrome

The specific value of IgA Anti-β2glycoprotein I antibodies (aB2GP1) in the diagnosis and management of antiphospholipid syndrome (APS) is still controversial and a matter of active debate. The relevance of the IgA aB2GP1 isotype in the pathophysiology of APS has been increasingly studied in the last years. There is well know that subjects with multiple positive APS tests are at increased risk of thrombosis and/or miscarriage. However, these antibodies are not included in the 2006 APS classification criteria. Since 2010 the task force of the Galveston International Congress on APS recommends testing IgA aB2GP1 isotype in patients with APS clinical criteria in the absence of criteria antibodies. In this review, we summarize the molecular and clinical “state of the art” of the IgA aB2GP in the context of APS. We also discuss some of the characteristics that may help to evaluate the real value of the IgA aB2GP1 determination in basic research and clinical practice. The scientific community should be aware of the importance of clarifying the role of IgA aB2GP1 in the APS diagnosis.

Systemic sclerosis and risk of cardiovascular disease: A PRISMA-compliant systemic review and meta-analysis of cohort studies

BACKGROUND

Systemic sclerosis (SSc) is an autoimmune disorder leading to extensive fibrosis and microvascular injury. Macrovascular disease is well documented in other autoimmune rheumatic diseases such as systemic lupus erythematosus and rheumatoid arthritis. However, the link is unclear between SSc and macrovascular disease, particularly atherosclerotic cardiovascular disease (CVD). This meta-analysis aimed to investigate the association between SSc and CVD.

METHODS

A thorough literature search was conducted in the Cochrane, Embase, Medline, and PubMed to identify all cohort studies comparing the risk of CVD with and without SSc. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) of cardiovascular end points were calculated. The risk of bias of included studies was assessed by the Newcastle-Ottawa scale.

RESULTS

Seven cohort studies with a total of 14,813 study participants were included. In a comparison of SSc patients versus non-SSc controls, the pooled HR for cardiovascular disease was 2.36 (95% CI 1.97-2.81); for peripheral vascular disease was 5.27 (95%CI 4.27-6.51); for myocardial infarction was 2.36 (95% CI 1.71-3.25); and for stroke was 1.52 (95% CI 1.18-1.96).

CONCLUSION

This meta-analysis revealed that SSc was associated with an increased risk of CVD. Clinicians who manage patients with SSc should be aware of the increased cardiovascular burden and undertake preventive measures.

Systemic sclerosis is an independent risk factor for ischemic heart disease, especially in patients carrying certain antiphospholipid antibodies: A large cross-sectional study

BACKGROUND

A higher prevalence of ischemic heart disease (IHD) in patients with systemic sclerosis (SSc) was reported. However, contrasting findings were published concerning the role of SSc-related autoantibodies in IHD risk which remains controversial. The current study explored the link between SSc and IHD, impact of putative links on SSc mortality and the role of SSc-related and antiphospholipid autoantibodies in disease associated IHD.

METHODS

A large cohort study utilising the Clalit-Health-Service (CHS) database was conducted on 2431 SSc patients and 12,710 age- and sex matched controls. The proportion of IHD was compared between patients diagnosed with SSc and age- and gender-matched controls. The role of SSc-linked and antiphospholipid autoantibodies in disease associated IHD was assessed.

RESULTS

The prevalence rate of IHD was significantly higher in SSc than controls (20.4% vs 15.0%, p <0.001). At the multivariate analysis, SSc was an independent predictor of IHD with an OR of 1.91 (95%CI 1.57-2.31, p < 0.0001). SSc patients with IHD had a higher mortality rate with an HR of 2.67 (95%CI 2.03-3.53, p < 0.0001) than those without IHD. In SSc patients positivity for anti-beta2GPI (IgM-isotype) or anti-cardiolipin (aCL) (IgA-isotype) represented a risk factor for IHD with an OR 1.89 (95% 1.04-3.45, p = 0.0369) and OR of 3.72 (95% 1.25-11.11, p = 0.0184), respectively.

CONCLUSIONS

Patients with SSc are at higher risk for developing IHD with an additional risk for the latter in those positive for aCL or anti-beta2GPI. A high degree of suspicion is needed during routine patient follow-up and pre-emptive screening should be considered.

Anti-phospholipid syndrome leading to digital ischaemia and rare organ complications in systemic sclerosis and related disorders

Antiphospholipid syndrome (APS) is an acquired, autoimmune thrombophilia that can occur as a primary disorder (with no associated disease) or secondary to infection, medication usage and autoimmune rheumatic diseases (ARDs). The association between APS and systemic lupus erythematosus (SLE) is well established, and practicing rheumatologists check for APS antibodies in the routine assessment of SLE, particularly if clinical features such as thrombotic events or pregnancy loss are present. APS secondary to systemic sclerosis (SSc)-related disorders is less widely recognised and easily overlooked. We describe 5 cases that highlight the varied breadth of clinical manifestations of APS in the context of SSc and related disorders. These cases range from uncomplicated Raynaud's phenomenon, digital ulceration/necrosis, critical digital ischaemia/gangrene and rare internal organ complications of APS in SSc-spectrum disorders. To our knowledge, our cases include the first reported case of secondary APS contributing to digital necrosis in the context of RACAND syndrome (Raynaud's phenomenon, anti-centromere antibodies and necrosis of the digits) and the first reported case of secondary APS in SSc causing posterior reversible encephalopathy syndrome (PRES). The case series is accompanied by a comprehensive review of the literature relevant to each case. Rheumatologists should be alert to the possibility of APS in SSc-spectrum disorders and should routinely check APS antibodies in all patients at diagnosis, and again later in the disease course if new features emerge that could indicate the presence of thrombotic events or other recognised APS manifestations. Key points • APS should be considered in all patients with digital ischaemic symptoms. • APS may be an important driver of SSc-related digital ulceration/necrosis. • Identification of SSc-associated APS opens up new therapeutic options for acute management and secondary prevention.

[Systemic sclerosis and macrovascular involvement: Status of the issue in 2019]

Systemic sclerosis (SSc) is a rare immune disease leading to fibrosis of the skin and internal organs. Microvasculopathy is a hallmark of SSc. However, some patients have severe macrovascular complications as affecting cerebral, cardiac or peripheral vessels. To date, macrovascular involvement in SSc remains a matter of debate. Many studies have shown an increased prevalence of macrovascular involvement in SSc in comparison with controlled subjects with similar cardiovascular risk factors. Various methods were used: ankle brachial pressure index, intima media thickness, imagery, coronary calcium score, pulse wave velocity, or flow mediated dilation. The pathophysiology of macrovascular involvement remains unknown and is probably multifactorial: accelerated atherosclerosis, endothelial dysfunction, or reflected wave of microvessel obliteration. The aim of this study was to perform a comprehensible review of the literature, through the study of different types of involved vessels. Results of the main studies are summarized in tables according to the method of investigation used.

Autoimmune connective tissue diseases and pregnancy

Autoimmune connective tissue-diseases are more frequent in women and deserve a multidisciplinary approach in which the dermatologist play a major role together with other physicians. Pregnancy in these patients has to be considered a high-risk situation, because of possible worsening of the mother's disease and increased morbility and mortality for the fetus; also, therapies have to be chosen carefully because some drugs cannot be used during pregnancy. For all these reasons, the decision to become pregnant needs to consider the type of disease, stage of disease, age and clinical condition, and requires a multidisciplinary approach. A correct counselling, a close monitoring, a specific approach based on the risks involved and the use of appropriate therapies are the keys to obtain optimal pregnancy outcomes.

Prevalence and Clinical Associations of Antiphospholipid Antibodies in Systemic Sclerosis: New Data From a French Cross-Sectional Study, Systematic Review, and Meta-Analysis

Objectives: Antiphospholipid antibodies (aPL) can be present in the sera of systemic sclerosis (SSc) patients. This study aimed to determine the prevalence of aPL in a cross-sectional study of SSc patients, to assess their clinical associations, to perform a systematic review of published reports and a meta-analysis to estimate the worldwide prevalence of aPL in SSc. Methods: Two-hundred and forty-nine SSc patients were consecutively tested once for lupus anticoagulant (LA), anticardiolipin (aCL), and anti-β2glycoprotein I (anti-β2GpI) antibodies. Clinical associations with aPL positivity were studied using a logistic regression model. A systematic review of the literature was carried out in PubMed and Embase. Meta-analysis was performed using number of aPL positive (at least one of the three antibodies positive) and negative patients. Meta-regression was used to study potential factors explaining the heterogeneity between studies. Results: In our cross-sectional study, aPL positivity was found in 16 patients (prevalence 6.4%; 95%CI [3.8-10.4]). In multivariate analysis, there was a significant association between aPL positivity and venous thrombosis (VT) (OR 6.25 [1.18-33.00]; p = 0.028) and miscarriage (OR 5.43; 95%CI [1.31-22.13]; p = 0.017). Twenty-four studies were included in the meta-analysis, representing a total population of 3036 SSc patients. The overall pooled prevalence of aPL in SSc was 14% (9-20) with a high degree of heterogeneity among studies. Conclusion: This study found a prevalence of aPL positivity in our SSc population of 6.4% (3.8-10.4) and an overall worldwide pooled prevalence of 14% (9-20). In our SSc population, aPL positivity was associated with VT and miscarriage. These data provide additional insights into the role of aPL in the vasculopathy observed in SSc.

Prevalence of auto-antibodies associated to pulmonary arterial hypertension in scleroderma - A review

The prevalence of auto-antibodies associated to pulmonary arterial hypertension in scleroderma patients was reviewed, based on reports cited in two major scientific databases. Data were collected on the following types of antibodies: antinuclear, anti-double-stranded DNA, anticentromere, anti-CENP-A, anti-CENP-B, anti-bicaudal D2, anti-nucleolar, anti-Scl-70 (anti-topoisomerase I), anti-topoisomerase II α, anti-RNP, anti-U1RNP, anti-U3RNP, anti-RNA polymerase III, anti-Th/To, anti-histone, antiphospholipid, anti-PmScl, anti-Sm, anti SSA (anti-Ro),anti SSB (La), anti-Ro52 (TRIM 21), anti-Ku, anti-B23, anti-RuvBL1, anti-RuvBL2, anti-fibrin bound tissue plasminogen activator, anti-endothelial cell, anti-phosphatidylserine-prothrombin complex, anti-endothelin-1 type A receptor, anti-angiotensin II type 1 receptor, anti‑carbonic anhydrase II, anti-fibroblast, anti-cyclic citrullinated peptide, anti-4-sulfated N-Acetyl-lactosamine, class I and II anti-human leukocyte antigen. Auto-antibodies were shown by different authors to be associated to this condition, with different prevalence values for each type of auto-antibody. Antinuclear antibodies, anti-centromere antibodies, antiphospholipid antibodies, anti-U3 RNP antibodies and anti-Th/To antibodies would appear to show a particularly important prevalence in scleroderma patients with pulmonary hypertension, appearing in about 8/10 (antinuclear), 1/ 2 (anti-centromere, anti-phospholipid), and 1/4 (anti-U3RNP, anti-Th/To) of patients. The available evidence points in the direction of a strong association between auto-immune mechanisms and pulmonary hypertension in the setting of scleroderma.

IgA anti-β2 glycoprotein I antibodies: Experience from a large center

OBJECTIVE

IgG and IgM antibodies directed at β2-glycoprotein I are included in the classification criteria for the antiphospholipid syndrome (APS) while the IgA antibodies against β2-glycoprotein I (IgA aβ2GPI) are not. Conflicting data about the significance of IgA aβ2GPI and APS manifestation can be found and more studies are necessary in order to define the diagnostic value of IgA aβ2GPI. In the present article, we investigated the possible role of IgA aβ2GPI as marker of APS.

METHODS

A cohort of 314 patients with APS and systemic autoimmune disease was investigated for the presence of IgA aβ2GPI and its association with clinical manifestation of APS.

RESULTS

Eighty-nine patients presented IgA aβ2GPI, 68 cases associated with others antiphospholipid antibodies (aPL) and in 21 cases being the only aPL present. In primary APS IgA aβ2GPI are highly coincidental with other aPL (92,2%) while most of the isolated IgA aβ2GPI were present in the SLE group (16/21). No association between IgA aβ2GPI and APS manifestations: thrombosis and pregnancy morbidity was found, while a positive association between IgA aβ2GPI and the presence of anti-nDNA, anti-RNP, anti-Sm, anti-SSA, anti-SSB antibodies was encountered.

CONCLUSION

Our study does not show association between IgA aβ2GPI and APS manifestations and does not support the inclusion of IgA aβ2GPI as a classification criteria for APS.

Clinical relevance of antiphospholipid antibodies in systemic sclerosis: A systematic review and meta-analysis

OBJECTIVE

To evaluate the clinical relevance of antiphospholipid antibodies (aPL) in systemic sclerosis (SSc).

METHODS

A systematic search of EMBASE and PubMed databases from January 1983 to July 2016 was carried out according to PRISMA guidelines whereas Peto׳s odds ratio (OR) for rare events was used for the meta-analysis.

RESULTS

The pooled prevalence of participants positive for IgG and IgM anticardiolipin (aCL) antibodies was higher in SSc than controls (12.8% vs 1.6% and 7.8% vs 0.6%; p < 0.0001 for both) as was that of IgG and IgM anti-beta-2-glycoprotein-I antibodies (aβ₂GPI) (6.1% vs 0.58%, p < 0.0001; 3.5% vs 0.3%, p = 0.001). The pooled prevalence of pulmonary arterial hypertension (PAH) was more common in SSc positive than negative patients for aCL (IgG/IgM combined) (26.5% vs 10.9%, p < 0.0001) whereas the pooled prevalence of renal disease (RD) was more common in IgG aCL positive than negative patients (36.3% vs 10.9%, p = 0.02). The pooled prevalence of thrombosis was higher in IgG aCL, IgM aCL, and IgM aβ₂GPI positive than negative SSc patients (12.6% vs 1.4%, p < 0.0001), (15.1% vs 2.7%, p = 0.002) and (15% vs 0.78%, p = 0.009), respectively. The pooled prevalence of digital infarction/ischemia (DI) was higher in IgG aCL and IgM positive than negative SSc (52.8% vs 39.8%, p = 0.002) and (68.1% vs 29%, p = 0.07).

CONCLUSIONS

A strong relationship exists between aCL and aβ₂GPI of IgG/IgM isotype and SSc; patients positive for these antibodies are more likely to suffer from PAH, RD, thrombosis, and DI. However, data expressed as frequency of aPL positive patients rather than average antibody titers preclude further insight into the relevance of these assumptions.

Nonthrombotic proliferative vasculopathy associated with antiphospholipid antibodies: A case report and literature review

A 20-year-old man presented with recurrent hemoptysis for seven months. A small subpleural nodule in his right lower lobe was found and excised surgically. Based on the presence of antiphospholipid antibodies (aPL) and vascular wall hypertrophy without vasculitis or an intraluminal thrombus, nonthrombotic proliferative vasculopathy (NTPV) affecting pulmonary arteries was diagnosed. Recently, aPL have been postulated to directly induce the proliferation of vascular cells in the intima and media, leading to NTPV. We review 5 cases of NTPV-associated aPL with critical ischemia in the lower extremities and gastrointestinal infarction. NTPV-associated aPL might be distinct from classic antiphospholipid syndrome and should be considered in aPL-positive patients who present with vascular occlusions of medium-sized vessels in the absence of atherosclerotic risk factors and systemic or local inflammation.

Raynaud's phenomenon

Raynaud's phenomenon (RP) is a major cause of pain and disability in patients with autoimmune connective tissue diseases (CTDs), particularly systemic sclerosis (SSc). The clinician must perform a comprehensive clinical assessment in patients with RP to differentiate between primary (idiopathic) and secondary RP, in particular (for rheumatologists), secondary to an autoimmune CTD, as both the prognosis and treatment may differ significantly. Key investigations are nailfold capillaroscopy and testing for autoantibodies (in particular, those associated with SSc). Patients with RP and either abnormal nailfold capillaroscopy or an SSc-specific antibody (and especially with both) have a high risk of transitioning to an autoimmune CTD. Both nailfold capillaroscopy and autoantibody specificity may help the clinician in predicting organ-based complications. The management of CTD-associated RP requires a multifaceted approach to treatment, including patient education and conservative ('non-drug') measures. Patients with CTD-associated RP often require pharmacological treatment, which in the first instance is usually a calcium channel blocker, although other agents can be used. There is an increasing tendency to use phosphodiesterase type 5 inhibitors early in the treatment of CTD-associated RP. Oral therapies are commonly associated with side effects (often due to systemic vasodilation) that may result in failure of dose escalation and/or permanent discontinuation. Intravenous prostanoid therapy and surgery (e.g., botulinum toxin injection and digital sympathectomy) can be considered in severe RP. Patients with CTD-associated RP can develop a number of ischaemic digital complications (primarily ulcers and critical ischaemia), which may be associated with significant tissue loss. Future research is required to increase the understanding of the pathogenesis and natural history of RP (to drive therapeutic advances), and to explore/develop drug therapies, including those that target the mechanisms mediating cold-induced vasoconstriction, and locally acting therapies free of systemic side effects.

[Large vessels vasculopathy in systemic sclerosis]

Vasculopathy in systemic sclerosis is a severe, in many cases irreversible, manifestation that can lead to amputation. While the classical clinical manifestations of the disease have to do with the involvement of microcirculation, proximal vessels of upper and lower limbs can also be affected. This involvement of large vessels may be related to systemic sclerosis, vasculitis or atherosclerotic, and the differential diagnosis is not easy. To conduct a proper and early diagnosis, it is essential to start prompt appropriate treatment. In this review, we examine the involvement of large vessels in scleroderma, an understudied manifestation with important prognostic and therapeutic implications.

Differential assay reactivity of immunglobulin A anti-ß2 glycoprotein I antibodies: implications for the clinical interpretation of antiphospholipid antibody testing

OBJECTIVE

The routine measurement of IgA anticardiolipin (aCL) and IgA anti-β₂ glycoprotein I (anti-β₂ GPI) antibodies remain controversial despite several studies demonstrating an association with thromboembolic disease in patients with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). This controversy may be a contributing factor for the current under use of IgA antiphospholipid antibodies. We aimed to investigate the nature of discrepant IgA anti-β₂ GPI reactivity to help define the diagnostic value of IgA antiphospholipid antibodies.

MATERIAL AND METHODS

Four sera selected from SLE/APS patients and positive for antiphospholipid antibodies but having discrepant IgA anti-β₂ GPI reactivity on two commercial assays were studied. IgA antibodies were affinity purified to investigate anti-β₂ GPI reactivity. Column wash through and eluent fractions were tested on both IgA anti-β₂ GPI assays. Results were normalized to total protein. Assay conjugates and standards from the discrepant assays were interchanged.

RESULTS

The diseased samples were strongly positive in one assay [144-388 IgA antiphospholipid (APL) units] and negative or weakly positive in another assay (9.9-53 APL units). IgA eluents from IgA anti-β₂ GPI positive samples reacted 10 times stronger on the reactive assay. When normalized to protein content, the eluents showed no cross-reactivity for IgG or IgM anti-β₂ GPI antibodies, confirming IgA isotype specificity. Conjugate interchange confirmed that both assays bound IgA anti-β₂ GPI antibodies, but the anti-IgA conjugate from the reactive assay was 4 times stronger, suggesting that its ability to detect IgA anti-β₂ GPI antibodies was partially dependent on the anti-IgA conjugate and calibration.

CONCLUSION

These results confirm not only the presence of IgA anti-β₂ GPI antibodies in the selected patient samples but also highlight an IgA conjugate issue for the unreactive assay, causing an underestimation of IgA anti-β₂ GPI. This finding may assist in the ongoing standardization efforts of APS antibody testing. In addition, conclusions from published clinical studies may need to be revised as some assays may understate IgA significance.

Association of anti phosphatidyl ethanolamine antibodies and low complement levels in systemic sclerosis patients--results of a cross-sectional study

Some systemic sclerosis (Ssc) patients express antiphospholipid antibodies and their percentage varies within studies in the literature. The particular role of these antibodies in clinical manifestations of Ssc is still unknown. The aim of the study was to examine an extended panel of antiphospholipid antibodies in Ssc patients who did not have any clinical features of antiphospholipid antibody syndrome. A cross-sectional study was designed and 36 consecutive patients with Ssc were recruited. A relatively high proportion of patients (14 patients - 38.9%) had antiphospholipid antibody presence. Most Ssc patients (11 patients - 30.6%) had IgM anti phosphatidyl ethanolamine antibodies. Serum IgM anti phosphatidyl ethanolamine antibodies, IgM anti prothrombin and IgG anti β2 glycoprotein 1 antibodies were associated with low complement levels in Ssc patients. In multivariate analysis, only serum IgM anti phosphatidyl ethanolamine antibodies concentration and serum IgG anti β2 glycoprotein 1 antibodies concentration were independently associated with hypocomplementemia after adjusting for age and gender. No other correlations with Ssc clinical characteristics were found. In conclusion, antiphospholipid antibodies are present in a large proportion of Ssc patients who do not have clinical features or a history of antiphospholipid antibodies. IgM anti phosphatidyl ethanolamine antibodies seem to be more frequent and the dominant antiphospholipid antibody type in the group recruited from the Romanian Ssc population.

Value of isolated IgA anti-β2 -glycoprotein I positivity in the diagnosis of the antiphospholipid syndrome

OBJECTIVE

To examine the prevalence of isolated IgA anti-β2 -glycoprotein I (anti-β2 GPI) positivity and the association of these antibodies, and a subgroup that bind specifically to domain IV/V of β2 GPI, with clinical manifestations of the antiphospholipid syndrome (APS) in 3 patient groups and to evaluate the pathogenicity of IgA anti-β2 GPI in a mouse model of thrombosis.

METHODS

Patients with systemic lupus erythematosus (SLE) from a multiethnic, multicenter cohort (LUpus in MInorities, NAture versus nurture [LUMINA]) (n = 558), patients with SLE from the Hopkins Lupus Cohort (n = 215), and serum samples referred to the Antiphospholipid Standardization Laboratory (APLS) (n = 5,098) were evaluated. IgA anti-β2 GPI titers and binding to domain IV/V of β2 GPI were examined by enzyme-linked immunosorbent assay (ELISA). CD1 mice were inoculated with purified IgA anti-β2 GPI antibodies, and surgical procedures and ELISAs were performed to evaluate thrombus development and tissue factor (TF) activity.

RESULTS

A total of 198 patients were found to be positive for IgA anti-β2 GPI isotype, and 57 patients were positive exclusively for IgA anti-β2 GPI antibodies. Of these, 13 of 23 patients (56.5%) in the LUMINA cohort, 17 of 17 patients (100%) in the Hopkins cohort, and 10 of 17 patients (58.9%) referred to APLS had at least one APS-related clinical manifestation. Fifty-four percent of all the IgA anti-β2 GPI-positive serum samples reacted with domain IV/V of anti-β2 GPI, and 77% of those had clinical features of APS. Isolated IgA anti-β2 GPI positivity was associated with an increased risk of arterial thrombosis (P < 0.001), venous thrombosis (P = 0.015), and all thrombosis (P < 0.001). The association between isolated IgA anti-β2 GPI and arterial thrombosis (P = 0.0003) and all thrombosis (P = 0.0003) remained significant after adjusting for other risk factors for thrombosis. In vivo mouse studies demonstrated that IgA anti-β2 GPI antibodies induced significantly larger thrombi and higher TF levels compared to controls.

CONCLUSION

Isolated IgA anti-β2 GPI-positive titers may identify additional patients with clinical features of APS. Testing for these antibodies when other antiphospholipid tests are negative and APS is suspected is recommended. IgA anti-β2 GPI antibodies directed to domain IV/V of β2 GPI represent an important subgroup of clinically relevant antiphospholipids.

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.

[Critical limb ischemia in systemic sclerosis]

Vascular complications are common in systemic sclerosis (SSc). Critical limb ischemia leading to gangrene or amputation occurs in more than 10% of these patients and hence is a common emergency. This report highlights the different pathogenetic mechanisms leading to critical ischemic events and provides guidance for the diagnosis and therapy. Apart from SSc-associated vasculopathy and peripheral arterial disease, thromboembolic events and rarely also vasculitis may cause critical limb ischemia. An interdisciplinary approach to the diagnosis and therapy of these lesions is mandatory. Therapy goals are the prevention of further ischemia and, if possible, revascularization as well as optimal pain management.

IgA antibodies against β2 glycoprotein I in hemodialysis patients are an independent risk factor for mortality

Cardiovascular complications are the most important cause of death in patients on dialysis with end-stage renal disease. Antibodies reacting with β-glycoprotein I seem to play a pathogenic role in antiphospholipid syndrome and stroke and are involved in the origin of atherosclerosis. Here we evaluated the presence of anticardiolipin and anti-β-glycoprotein I antibodies together with other vascular risk factors and their relationship with mortality and cardiovascular morbidity in a cohort of 124 hemodialysis patients prospectively followed for 2 years. Of these, 41 patients were significantly positive for IgA anti-β-glycoprotein I, and the remaining had normal values. At 24 months, overall and cardiovascular mortality and thrombotic events were all significantly higher in patients with high anti-β-glycoprotein I antibodies. Multivariate analysis using Cox regression modeling found that age, hypoalbuminemia, use of dialysis catheters, and IgA β-glycoprotein I antibodies were independent risk factors for death. Thus, IgA antibodies to β-glycoprotein I are detrimental to the clinical outcome of hemodialysis patients.

Induction of anti-β2 -glycoprotein I autoantibodies in mice by protein H of Streptococcus pyogenes

BACKGROUND

The antiphospholipid syndrome (APS) is characterized by the persistent presence of anti-β(2) -glycoprotein I (β(2) -GPI) autoantibodies. β(2) -GPI can exist in two conformations. In plasma it is a circular protein, whereas it adopts a fish-hook conformation after binding to phospholipids. Only the latter conformation is recognized by patient antibodies. β(2) -GPI has been shown to interact with Streptococcus pyogenes.

OBJECTIVE

To evaluate the potential of S. pyogenes-derived proteins to induce anti-β(2) -GPI autoantibodies.

METHODS AND RESULTS

Four S. pyogenes surface proteins (M1 protein, protein H, streptococcal collagen-like protein A [SclA], and streptococcal collagen-like protein B [SclB]) were found to interact with β(2) -GPI. Only binding to protein H induces a conformational change in β(2) -GPI, thereby exposing a cryptic epitope for APS-related autoantibodies. Mice were injected with the four proteins. Only mice injected with protein H developed antibodies against the patient antibody-related epitope in domain I of β(2) -GPI. Patients with pharyngotonsillitis caused by S. pyogenes who developed anti-protein H antibodies also generated anti-β(2) -GPI antibodies.

CONCLUSIONS

Our study has demonstrated that a bacterial protein can induce a conformational change in β(2) -GPI, resulting in the formation of antiβ(2) -GPI autoantibodies. This constitutes a novel mechanism for the formation of anti-β(2) -GPI autoantibodies.

Cardiovascular disease in systemic sclerosis--an emerging association?

Microvascular disease is a prominent feature of systemic sclerosis (SSc) and leads to Raynaud's phenomenon, pulmonary arterial hypertension, and scleroderma renal crisis. The presence of macrovascular disease is less well established, and, in particular, it is not known whether the prevalence of coronary heart disease in SSc is increased. Furthermore, in terms of cardiac involvement in SSc, there remains conjecture about the relative contributions of atherosclerotic macrovascular disease and myocardial microvascular disease. In this review, we summarize the literature describing cardiovascular disease in SSc, discuss the pathophysiological mechanisms common to SSc and atherosclerosis, and review the surrogate markers of cardiovascular disease which have been examined in SSc. Proposed mediators of the vasculopathy of SSc which have also been implicated in atherosclerosis include endothelial dysfunction, a reduced number of circulating endothelial progenitor cells, and an increased number of microparticles. Excess cardiovascular risk in SSc is suggested by increased arterial stiffness and carotid intima thickening and reduced flow-mediated dilatation. Cohort studies of adequate size are required to resolve whether this translates into an increased incidence of cardiovascular events in patients with SSc.

'Non-criteria' aPL tests: report of a task force and preconference workshop at the 13th International Congress on Antiphospholipid Antibodies, Galveston, TX, USA, April 2010

Abstract: Current classification criteria for definite APS recommend the use of one or more of three positive standardized laboratory assays, including anticardiolipin antibodies (aCL), lupus anticoagulant (LA), and antibodies directed to β(2)glycoprotein I (anti-β(2)GPI) to detect antiphospholipid antibodies (aPL) in the presence of at least one of the two major clinical manifestations (i.e., thrombosis or pregnancy morbidity) of the syndrome. Several other autoantibodies shown to be directed to phospholipids and/or their complexes with phospholipids and/or to proteins of the coagulation cascade, as well as a mechanistic test for resistance to annexin A5 anticoagulant activity, have been proposed to be relevant to APS. A task force of worldwide scientists in the field discussed and analyzed critical questions related to 'non-criteria' aPL tests in an evidence-based manner during the 13th International Congress on Antiphospholipid Antibodies (APLA 2010, 13-16 April 2010, Galveston, Texas, USA). This report summarizes the findings, conclusions, and recommendations of this task force.

Digital ischemic loss in systemic sclerosis

Digital ischemic loss is a cause of significant morbidity in patients with systemic sclerosis (SSc). Microvascular disease with intimal proliferation and luminal narrowing of small digital arteries, as well as macrovascular disease with narrowing or occlusion of larger digital arteries, contribute to the perfusion defects involved in digital ischemic loss. Immediate clinical evaluation and treatment are mandatory at the onset of critical digital ischemia to prevent digital loss. Hospitalization for medical therapies including intravenous prostacyclin therapy should be considered for all SSc patients who present with critical digital ischemia. Surgical interventions are typically reserved for patients who fail medical therapies and for those with late stage, necrotic tissue. This paper summarizes the current knowledge regarding the risk factors, pathogenesis, evaluation, and treatment of digital ischemic loss in SSc.

IgA anti-beta2-glycoprotein I autoantibodies are associated with an increased risk of thromboembolic events in patients with systemic lupus erythematosus

BACKGROUND

The clinical utility of testing for antiphospholipid antibodies (aPL) of IgA isotype remains controversial.

METHODOLOGY/PRINCIPAL FINDINGS

To address this issue, we reasoned that if IgA aPL contribute to the clinical manifestations of the antiphospholipid syndrome, then an association with thromboembolic events should manifest in patients whose only aPL is of IgA isotype. We performed a retrospective chart review of 56 patients (31 with systemic lupus erythematosus [SLE] and 25 without SLE) whose only positive aPL was IgA anti-beta2-glycoprotein I (isolated IgA anti-beta2GPI) and compared their clinical features with 56 individually matched control patients without any aPL. Patients with isolated IgA anti-beta2GPI had a significantly increased number of thromboembolic events, as compared to controls. When patients were stratified into those with and without SLE, the association between isolated IgA anti-beta2GPI and thromboembolic events persisted for patients with SLE, but was lost for those without SLE. Titers of IgA anti-beta2GPI were significantly higher in SLE patients who suffered a thromboembolic event. Among patients with isolated IgA anti-beta2GPI, there was an increased prevalence of diseases or morbidities involving organs of mucosal immunity (i.e., gastrointestinal system, pulmonary system, and skin).

CONCLUSIONS/SIGNIFICANCE

The presence of isolated IgA anti-beta2GPI is associated with an increased risk of thromboembolic events, especially among patients with SLE. IgA anti-beta2GPI is associated with an increased prevalence of morbidities involving organs of mucosal immunity.

The burden and measurement of cardiovascular disease in SSc

The prognosis for patients with systemic sclerosis (SSc) has improved in the past three decades, with fewer patients succumbing to renal-crisis-related death. While pulmonary fibrosis and hypertension are currently the most frequent causes of death, there is evidence that cardiovascular disease will have an important role in the long-term prognosis of SSc in the future. Ischemia-reperfusion injury and endothelial dysfunction are cardinal features of SSc, and may predispose a patient to microvascular disease and atherosclerosis. In order to alleviate the cardiovascular burden in patients with SSc, it is important to detect endothelial dysfunction, microvascular flow disturbance and atherosclerosis. Noninvasive techniques that evaluate flow-mediated dilatation and arterial pulse waves (endothelial function measurements), microvascular blood flow (measurement of the microcirculation), carotid intima-media thickness and left ventricular hypertrophy (detection of atherosclerosis) are recommended. In addition, these measurements will facilitate trials of therapeutic strategies that, in addition to controlling conventional risk factors, prevent and treat cardiovascular disease in patients with SSc.