Thrombotic recurrences and bleeding events in APS vascular patients: a review from the literature and a comparison with the APS Piedmont Cohort

Whole blood transcriptome identifies interferon-regulated genes as key drivers in thrombotic primary antiphospholipid syndrome

OBJECTIVE

Pathogenesis of antiphospholipid syndrome (APS) isn't fully elucidated. We aimed to identify gene signatures characterizing thrombotic primary APS (thrPAPS) and subgroups at high risk for worse outcomes.

METHODS

We performed whole blood next-generation RNA-sequencing in 62 patients with thrPAPS and 29 age-/sex-matched healthy controls (HCs), followed by differential gene expression analysis (DGEA) and enrichment analysis. We trained models on transcriptomics data using machine learning.

RESULTS

DGEA of 12.306 genes revealed 34 deregulated genes in thrPAPS versus HCs; 33 were upregulated by at least 2-fold, and 14/33 were type I and II interferon-regulated genes (IRGs) as determined by interferome database. Machine learning applied to deregulated genes returned 79% accuracy to discriminate thrPAPS from HCs, which increased to 82% when only the most informative IRGs were analyzed. Comparison of thrPAPS subgroups versus HCs showed an increased presence of IRGs among upregulated genes in venous thrombosis (21/23, 91%), triple-antiphospholipid antibody (aPL) positive (30/50, 60%), and recurrent thrombosis (19/42, 45%) subgroups. Enrichment analysis of upregulated genes in triple-aPL positive patients revealed terms related to 'type I interferon signaling pathway' and 'innate immune response'. DGEA among thrPAPS subgroups revealed upregulated genes, including IRGs, in patients with venous versus arterial thrombosis (n = 11, 9 IRGs), triple-aPL versus non-triple aPL (n = 10, 9 IRGs), and recurrent versus non-recurrent thrombosis (n = 10, 3 IRGs).

CONCLUSION

Upregulated IRGs may better discriminate thrPAPS from HCs than all deregulated genes in peripheral blood. Taken together with DGEA data, IRGs are highly expressed in thrPAPS and high-risk subgroups of triple-aPL and recurrent thrombosis, with potential treatment implications.

"How we treat" clinical dilemmas in antiphospholipid syndrome: A case-based approach

Antiphospholipid syndrome (APS) is an autoimmune condition characterized by thrombosis (arterial, venous, and microvascular) and/or pregnancy morbidity occurring in subjects persistently positive for antiphospholipid antibodies (aPL). While the APS classification criteria are being currently updated to improve homogeneity in clinical research, patients who seek medical treatment often have a variety of laboratory and clinical characteristics that may not completely fulfill the classification criteria for overt APS. Those cases might represent a challenge in terms of treatment and overall management. We aim to present a collection of challenging scenarios of patients who tested positive for aPL and to discuss available literature to guide the therapeutic strategies.

Patterns of Recurrent Thrombosis in Primary Antiphospholipid Syndrome-Multicenter, Real-Life Long-Term Follow-Up

Background

Antiphospholipid syndrome (APS) is an acquired hypercoagulable condition associated with antiphospholipid antibody (aPL) presence. Data on re-thrombosis following APS-diagnosis are limited.

Methods

This is a retrospective analysis of new thrombotic events among primary APS (pAPS) patients followed for up to 15 years in three medical centers in Israel.

Results

Among 312 primary-APS patients, 143 (46%) had new thrombotic event classified to three patterns: (1) Arterial—associated with heart valve disease (OR 7.24, 95% C.I. 2.26–24.6), hypertension (OR 3, 95% C.I. 1.44–6.25), elevated anti-B2-GPI IgM (OR 1.04, 95% C.I. 0.996–1.08), arterial thrombosis at presentation (OR 1.74 95% C.I. 0.992–3.26), and older age (41 vs. 34 years, p < 0.001). (2) Venous—linked with venous thrombosis at presentation (OR 12.9, 95% C.I. 5.27–31.6, p < 0.001), heart valve disease (OR 9.81 95% C.I. 1.82–52.9, p = 0.018), aGAPSS (OR 1.15 95% C.I. 1.02–1.29), and younger age (31 vs. 36.5 years, p = 0.001); and (3) Combined pattern—associated with heart valve disease (OR 40.5 95% C.I. 7.7–212) and pulmonary embolism (OR 7.47 95% C.I. 1.96–28.5). A 4th variant “the Breakthrough pattern” defined by re-thrombosis despite prophylactic therapy was observed in 100/143 (70%) patients and linked with heart valve disease (OR 8. 95% C.I. 2.43–26.3), venous thrombosis at presentation (OR 2.61 95% C.I. 1.47–4.66), leg ulcers (OR 12.2, 95% C.I. 1.4–107), hypertension (OR 1.99, 95% C.I. 0.92–4.34), and higher aGAPSS (OR 1.08, 95% C.I. 0.99–1.18).

Conclusion

In this real-life observation, re-thrombosis was common among pAPS patients including in those recommended to receive prophylactic therapy. Different patterns of recurrence were identified and linked with presenting symptoms, specific serological markers, APS manifestations, and comorbidities. Studies that will address interventions to prevent recurrences of APS-related events are needed.

What is the appropriate anticoagulation strategy for thrombotic antiphospholipid syndrome?

Antiphospholipid syndrome (APS) is an autoimmune prothrombotic disorder mediated by a heterogeneous group of autoantibodies collectively known as antiphospholipid antibodies (aPL). They include lupus anticoagulant (LA), IgG and IgM anticardiolipin antibodies (aCL) and anti-β2-glycoprotein I (anti-β2GPI) antibodies. It has been shown that those patients with all three aPL (triple positive) are at highest risk of both a first thrombotic event and of a recurrence, despite anticoagulation. In response to publication of a meta-analysis and a randomised controlled trial assessing the safety and efficacy of rivaroxaban versus warfarin in triple-positive APS with venous and/or arterial thrombosis, the Medicines and Healthcare Products Regulatory Agency (MHRA) and European Medicines Agency (EMA) issued recommendations that direct-acting oral anticoagulant (DOACs) should not be used for secondary prevention of thrombosis in all APS patients (although they did draw specific attention to the high risk of triple-positive patients). As there is less evidence for patients with single- or dual-positive patients with APS, this may be an over-interpretation of the data. In this review, we explore the available evidence on safety and efficacy of DOACs in thrombotic APS, the problem of detecting LA while on DOAC, and provide some practical guidance for managing this problem.

A challenging case of neuropsychiatric systematic lupus erythematosus with recurrent antiphospholipid- related stroke: A case report and literature review

Neuropsychiatic systematic lupus erythematosus (NPSLE) is a form of SLE involves the inflammation and/or thrombotic event in the nervous system. Patients with NPSLE are likely to have a positive antiphospholipid antibody (aPL), therefore are at higher risk of recurrent ischemic stroke. The management of NPSLE with aPLrelated stroke is rather different from the traditional ischemic stroke. One must treat it with anticoagulation and immunosuppressive therapy. The present case is a 47-yearold Taiwanese female with NPSLE and positive aPL, presented with a recurrent MCA ischemic stroke. Initial laboratory results showed significantly elevated levels of anti-ANA, anti-dsDNA, anti-cardiolipin, and decreased complement levels. Due to multiple contraindications for tPA, she was treated with antiplatelet, anticoagulation, steroid pulse therapy, and plasmapheresis during the hospitalization. Despite treatments, her stroke progressed to multi-focal lesions, involving the ACA, MCA, and basal ganglion. On follow up of her brain CT scan showed tissue edema and suspicious for subfalcine herniation. Responding to this clinical deterioration, we stopped warfarin and started mannitol. Eventually, her condition improved and was transferred to the rehabilitation program. Currently, there is no unified guideline regarding the secondary prevention of ischemic stroke in NPSLE with aPL patients. Additionally, previously reported use of steroid pulse therapy and plasmapheresis can potentially harm the patient. Clinicians must be cautious when treating such patient.

Acute myocardial infarction in a patient positive for lupus anticoagulant: a case report

Background

Autoimmune diseases, such as systemic lupus erythematosus (SLE), are associated with thrombosis and atherosclerosis. Presence of lupus anticoagulant is an independent risk factor for atherosclerotic diseases.

Case presentation

A 56-year-old man with past history of hypertension, and cerebral infarction was admitted to our hospital owing to acute chest pain. He was diagnosed with acute myocardial infarction based on his symptoms and electrocardiogram results, which demonstrated ST elevation in the precordial leads. Coronary angiography images revealed total occlusion at the proximal site of the left anterior descending artery. A drug-eluting stent was deployed, which successfully recovered coronary blood flow. The patient had fever of unknown cause when he was 30 years old; on admission, he presented with a low-grade fever and reddish exanthema affecting both cheeks. Based on his physical signs as well as elevated antinuclear antibodies (anti-double-stranded DNA), decreased lymphocytes, and a positive direct Coombs test, he was diagnosed with SLE. Owing to a positive lupus anticoagulant test, he was also suspected to have antiphospholipid syndrome (APS). Triple antithrombotic therapy, including dual antiplatelet therapy with aspirin and clopidogrel during coronary stenting and single anticoagulation therapy with warfarin, was initiated.

Conclusions

Careful diagnosis of autoimmune diseases should be performed in patients with thrombosis and atherosclerosis. Moreover, risk factors for coronary artery disease should be strictly controlled in patients with APS.

The treatment of anti-phospholipid syndrome: A comprehensive clinical approach

Anti-phospholipid syndrome (APS) is an acquired pro-thrombotic autoimmune disease that predisposes to thrombotic events and/or obstetric complications, in the persistent presence of anti-phospholipid antibodies (aPL). Life long moderate-intensity anticoagulation is the option of choice for aPL-positive patients with a previous thrombosis; critical issues concern the management of those with a history of arterial event due to the high rate of recurrence. Alternatives comprise anti-platelet agents and high-intensity anticoagulation. Low dose aspirin (LDASA) and low molecular weight heparin provide the mainstay of the treatment of obstetric APS, allowing a birth rate in 70% of cases. The management of refractory APS, thrombotic as well as obstetric, is highly debated, but an increasing burden of evidence points towards the beneficial effects of multiple treatments. Similarly, a management envisaging multiple drugs (anticoagulation, steroids, plasma exchange and/or intravenous immunoglobulins) is the most effective approach in catastrophic APS. Asymptomatic aPL carriers are at higher risk of thrombotic and obstetric complications compared to the general population, thus potentially benefitting of a pharmacological intervention. LDASA and hydroxychloroquine can be considered as options, in particular in case of high risk aPL profile, concomitant cardiovascular risk factors or associated autoimmune disease. APS is apparently a simple condition, but its multifaceted nature requires a complex and tailored treatment.

Incidence of thromboembolic events in asymptomatic carriers of IgA anti ß2 glycoprotein-I antibodies

BACKGROUND

The antiphospholipid syndrome (APS) is defined by simultaneous presence of vascular clinical events and antiphospholipid antibodies (aPL). The aPL considered as diagnostics are lupus anticoagulant and antibodies anticardiolipin (aCL) and anti-ß2 glycoprotein-I (aB2GP1). During recent years, IgA aB2GP1 antibodies have been associated with thrombotic events both in patients positive, and mainly negative for other aPL, however its value as a pro-thrombotic risk-factor in asymptomatic patients has not been well defined.

OBJECTIVE

To test the role of IgA anti B2GP1 as a risk factor for the development of APS-events (thrombosis or pregnancy morbidity) in asymptomatic population with a 5-year follow-up.

METHODS

244 patients isolated positive for anti-beta2-glycoprotein I IgA (Group-1 study) and 221 negative patients (Group-2 control) were studied. All the patients were negative for IgG and IgM aCL.

RESULTS

During the follow-up, 45 patients (9.7%) had APS-events, 38 positive for IgA-aB2GP1 and 7 negative (15.6% vs 3.2%, p<0.001). The incidence rate of APS-events was 3.1% per year in IgA-aB2GP1 positive patients and 0.6% per year in the control group. Arterial thrombosis were the most frequent APS-events (N = 25, 55%) and were mainly observed in Group-1 patients (21 vs 4, p = 0.001). Multivariate analysis were shown as independent risk-factors for the development of APS-events, age, sex (men) and presence of IgA-aB2GP1 (odds ratio 5.25, 95% CI 2.24 to 12.32).

CONCLUSION

The presence of IgA-aB2GP1 in people with no history of APS-events is the main independent risk factor for the development of these types of events, mainly arterial thrombosis.

Anticoagulation withdrawal in antiphospholipid syndrome: a retrospective matched-control study

Background/Purpose

Long-term anticoagulation is the standard treatment for thrombotic antiphospholipid syndrome (APS). However, in daily practice, the question of withdrawing anticoagulation may arise, without any evidence-based recommendations. This study aimed to assess outcomes in APS patients after anticoagulation withdrawal.

Methods

Thrombotic APS patients followed in our centre, whose anticoagulation was withdrawn after APS diagnosis, were retrospectively selected, and were match-controlled with patients under anticoagulation, based on sex, age, APS clinical phenotype and disease duration.

Results

Thirty cases with anticoagulation withdrawal were included. Median follow-up was 51 months (12–124). The risk of thrombotic relapse was higher in cases compared to controls (7.3% versus 1.5% patient-year ( p = 0.01); hazard ratio 4.8; 95% confidence interval (1.4–16.7)). Male gender, anti-β2GP1 and triple positivity at inclusion were predictive factors for thrombotic relapse. Conversely, aspirin prescription was a protective factor against relapses. Persistence of LA, anti-β2GP1 and triple positivity over time were associated with a higher risk of thrombosis and aPL disappearance with a lower risk.

Conclusion

In our study, anticoagulation withdrawal was associated with an increased risk of thrombotic relapse. Our findings emphasize the influence of anti-β2GP1 and triple positivity persistence over time on the risk of relapse and the benefit of aspirin prescription when anticoagulation has been withdrawn.

Dimerized Domain V of Beta2-Glycoprotein I Is Sufficient to Upregulate Procoagulant Activity in PMA-Treated U937 Monocytes and Require Intact Residues in Two Phospholipid-Binding Loops

Upregulation of the procoagulant activity of monocytes by antibodies to beta2- glycoprotein I (β2GPI) is one of the mechanisms contributing to thrombosis in antiphospholipid syndrome. Current knowledge about receptors responsible for the upregulation of procoagulant activity by β2GPI/anti-β2GPI complexes and their binding sites on β2GPI is far from complete. We quantified the procoagulant activity expressed by phorbol 12-myristate 13-acetate (PMA)- differentiated U937 cells by measuring clotting kinetics in human plasma exposed to stimulated cells. Cells stimulated with anti-β2GPI were compared to cells treated with dimerized domain V of β2GPI (β2GPI-DV) or point mutants of β2GPI-DV. We demonstrated that dimerized β2GPI-DV is sufficient to induce procoagulant activity in monocytes. Using site-directed mutagenesis, we determined that the phospholipid-binding interface on β2GPI is larger than previously thought and includes Lys308 in β2GPI-DV. Intact residues in two phospholipid-binding loops of β2GPI-DV were important for the potentiation of procoagulant activity. We did not detect a correlation between the ability of β2GPI-DV variants to bind ApoER2 and potentiation of the procoagulant activity of cells. The region on β2GPI inducing procoagulant activity in monocytes can now be narrowed down to β2GPI-DV. The ability of β2GPI-DV dimers to come close to cell membrane and attach to it is important for the stimulation of procoagulant activity.

An Overview of Thrombophilia and Associated Laboratory Testing

Venous thromboembolism, usually entailing deep vein thrombosis, pulmonary embolism, or both, is a complex and multifactorial disorder, in which a number of putative conditions interplay and finally contribute to propel the individual risk over a certain degree, so ultimately culminating in the development of venous occlusive disorders. Thrombophilia is commonly defined as a propensity to develop venous thromboembolism on the basis of an underlying hypercoagulable state attributable to inherited or acquired disorders of blood coagulation or fibrinolysis. The thrombophilic conditions are conventionally classified as inherited (or genetically determined) and acquired. The former include deficiencies of natural anticoagulants such as antithrombin, protein C, protein S, increased values of clotting factors (especially factor VIII), as well as prothrombotic polymorphisms in genes encoding for factor V (i.e., factor V Leiden) and prothrombin. The latter conditions mainly entail antiphospholipid antibody syndrome, malignancy, acquired elevations of coagulation factors or acquired reduction of natural inhibitors, or hyperhomocysteinemia. Deepened knowledge of all potential risk factors, as well as the clear understanding of their role in the pathophysiology of venous thrombosis, are both essential to help achieve a faster and more efficient diagnosis of this condition as well as a more effective prophylaxis of patients at higher risk and treatment of those with manifest disease.

Soluble analog of ApoER2 targeting beta2-glycoprotein I in immune complexes counteracts hypertension in lupus-prone mice with spontaneous antiphospholipid syndrome

Essentials (NZWxBXSB)F1 male mice develop antibodies beta2-glycoprotein I (β2GPI) and hypertension. A1-A1 is a soluble analogue of ApoE receptor 2 with a high affinity for β2GPI/antibody complexes. A1-A1 improved blood pressure and arterial elastance in (NZWxBXSB)F1 male mice. A1-A1 had no adverse effects on the hemodynamics of healthy mice.

SUMMARY

Background Antiphospholipid syndrome (APS) is diagnosed based on the presence of antiphospholipid antibodies and clinical thrombosis or fetal loss during pregnancy. Lupus-prone (NZWxBXSB)F1 male mice are the mouse model of spontaneous APS. They develop anti-β2GPI antibodies, microinfarcts and hypertension. ApoER2 is a receptor that contributes to anti-β2GPI-dependent thrombosis in APS by down-regulating endothelial nitric oxide synthase activation. Objectives A1-A1 is a small protein constructed from two identical ligand-binding modules from ApoER2, containing the binding site for β2GPI. We studied how treatment with A1-A1 affects the development of hypertension in (NZWxBXSB)F1 male mice. Methods We treated (NZWxBXSB)F1 male mice with A1-A1 for up to 4 weeks and examined changes in hemodynamics by left ventricular pressure-volume loop measurements. Results We observed improvements in blood pressure in the A1-A1 treated mice. A1-A1 prevented the deterioration of arterial elastance by decreasing systemic resistance and improving vessel compliance. We did not detect any adverse effects of the treatment in either male mice or in apparently healthy female (NZWxBXSB)F1 mice. Conclusions We demonstrated that A1-A1, which is a soluble analog of ApoER2 that binds pathological β2GPI/anti-β2GPI complexes, has a positive impact on hemodynamics in lupus-prone mice with spontaneous anti-β2GPI antibodies and hypertension.

Analytical and clinical comparison of different immunoassay systems for the detection of antiphospholipid antibodies

INTRODUCTION

We evaluated analytical and clinical performances of IgG and IgM anticardiolipin (aCL) antibodies and anti-β2-glycoprotein I (a-β2GpI) antibodies and upper limit reference ranges (99th percentiles) in comparison with manufacturer's cutoff values with different commercial methods.

METHODS

We assayed aCL and a-β2GpI in serum samples from 30 healthy individuals, 77 patients with antiphospholipid syndrome (APS) diagnosed according to the Sydney criteria, 51 patients with autoimmune diseases, eight patients with previous thrombotic events, six patients with other diseases, and 18 patients with infectious diseases, using ELISA Inova Diagnostics; EliA Phadia Laboratory Systems; CliA Zenit-RA; and CliA Bio-Flash.

RESULTS

Anticardiolipin and a-β2GpI IgG and IgM immunoassays showed good analytic performances with both 99th percentile and manufacturer's cutoff reference values. Our results showed fair to moderate agreement among assays. In-house cutoff values gave significantly better performances only for a-β2GpI IgG with all the immunoassays analyzed with the exception of Inova CliA Bio-Flash where we obtained the same performances with in-house and manufacturer's cutoffs.

CONCLUSIONS

By guidelines, all laboratories are strongly advised to validate/verify the manufacturer's cutoff values. We recommend establishing low-positive, medium-/high-positive, and high-positive CliA IgG aCL and a-β2GpI ranges in order to help clinicians in the diagnosis and treatment of APS.

Patients with antiphosholipid syndrome and thrombotic recurrences: A real world observation (the Piedmont cohort study)

BACKGROUND

Patients with antiphospholipid syndrome (APS) often have thrombotic recurrences, sometimes despite appropriate ongoing anticoagulant treatment. Identifying APS vascular patients at high risk for thrombotic recurrences is still an unsolved issue.

OBJECTIVES

To report the real-life experience of thrombotic recurrences in APS patients included in the Piedmont observational cohort study, and evaluate clinical and laboratory risk factors for thrombotic recurrences.

PATIENTS

A multi-centre observational study was performed by enrolling 177 patients with vascular APS (primary APS in 99 subjects (56%)); the median follow-up was five years (range 1-26 years).

RESULTS

The observed thrombotic recurrence rate was about 7.5/100 patient years in the first five years after the first thrombotic event. While the first recurrence often occurred (45%) in patients who were not on oral anticoagulant therapy (OAT), the second recurrence mainly occurred despite ongoing OAT (80%). However, due to the real-life observational nature of this study, treatment was based on the treating physician's judgement, and no structured therapeutic protocol was applied. Moreover, compliance with OAT was not available. No differences in antiphospholipid antibodies (aPL) profile were observed between patients with or without thrombotic recurrences, but a high risk aPL profile (Miyakis type 1 and 2a) was present in 96% of our patients, 26% of whom had triple positivity. Diabetes (p < 0.01, OR 10), inherited thrombophilia (p < 0.0078, OR 4) and OAT withdrawal were independent risk factors for recurrences.

CONCLUSIONS

With the limit of a real-life observational cohort study, the thrombotic recurrence rate in APS was as high as 7.5/100 patient years in the first five years after the first thrombotic event. OAT discontinuation, diabetes and inherited thrombophilia, when associated with a high-risk aPL profile, are risk factors for thrombotic recurrences.

Autoimmunity in 2013

The peer-reviewed publications in the field of autoimmunity published in 2013 represented a significant proportion of immunology articles and grew since the previous year to indicate that more immune-mediated phenomena may recognize an autoimmune mechanism and illustrated by osteoarthritis and atherosclerosis. As a result, our understanding of the mechanisms of autoimmunity is becoming the paradigm for translational research in which the progress in disease pathogenesis for both tolerance breakdown and inflammation perpetuation is rapidly followed by new treatment approaches and clinical management changes. The similarities across the autoimmune disease spectrum outnumber differences, particularly when treatments are compared. Indeed, the therapeutics of autoimmune diseases are based on a growing armamentarium that currently includes monoclonal antibodies and small molecules which act by targeting molecular markers or intracellular mediators with high specificity. Among the over 100 conditions considered as autoimmune, the common grounds are well illustrated by the data reported for systemic lupus erythematosus and rheumatoid arthritis or by the plethora of studies on Th17 cells and biomarkers, particularly serum autoantibodies. Further, we are particularly intrigued by studies on the genomics, epigenetics, and microRNA at different stages of disease development or on the safe and effective use of abatacept acting on the costimulation of T and B cells in rheumatoid arthritis. We are convinced that the data published in 2013 represent a promising background for future developments that will exponentially impact the work of laboratory and clinical scientists over the next years.

Treatment of Thrombotic Antiphospholipid Syndrome: The Rationale of Current Management-An Insight into Future Approaches

Vascular thrombosis and pregnancy morbidity represent the clinical manifestations of antiphospholipid syndrome (APS), which is serologically characterized by the persistent positivity of antiphospholipid antibodies (aPL). Antiplatelet and anticoagulant agents currently provide the mainstay of APS treatment. However, the debate is still open: controversies involve the intensity and the duration of anticoagulation and the treatment of stroke and refractory cases. Unfortunately, the literature cannot provide definite answers to these controversial issues as it is flawed by many limitations, mainly due to the recruitment of patients not fulfilling laboratory and clinical criteria for APS. The recommended therapeutic management of different aPL-related clinical manifestations is hereby presented, with a critical appraisal of the evidence supporting such approaches. Cutting edge therapeutic strategies are also discussed, presenting the pioneer reports about the efficacy of novel pharmacological agents in APS. Thanks to a better understanding of aPL pathogenic mechanisms, new therapeutic targets will soon be explored. Much work is still to be done to unravel the most controversial issues about APS management: future studies are warranted to define the optimal management according to aPL risk profile and to assess the impact of a strict control of cardiovascular risk factors on disease control.

Systemic lupus erythematosus and thrombosis

Systemic Lupus Erythematosus (SLE) is an acquired, multiorgan, autoimmune disease. Clinical presentation is extremely variable and heterogeneous. It has been shown that SLE itself is an independent risk factor for developing both arterial and venous thrombotic events since SLE patients have an Odds Ratio (OR) for thrombosis that varies depending on the clinical and laboratory characteristics of each study cohort. The risk of developing a thrombotic event is higher in this setting than in the general population and may further increase when associated with other risk factors, or in the presence of inherited or acquired pro-thrombotic abnormalities, or trigger events. In particular, a striking increase in the number of thrombotic events was observed when SLE was associated with antiphospholipid antibodies (aPL). The presence of aPLs has been described in about 50% of SLE patients, while about 20% of antiphospholipid syndrome (APS) patients have SLE. While APS patients (with or without an autoimmune disease) have been widely studied in the last years, fewer studies are available for SLE patients and thrombosis in the absence of APS. Although the available literature undoubtedly shows that SLE patients have a greater prevalence of thrombotic events as compared to healthy subjects, it is difficult to obtain a definite result from these studies because in some cases the study cohort was too small, in others it is due to the varied characteristics of the study population, or because of the different (and very copious) laboratory assays and methods that were used. When an SLE patient develops a thrombotic event, it is of great clinical relevance since it is potentially life-threatening. Moreover, it worsens the quality of life and is a clinical challenge for the clinician.

Hydroxychloroquine as an anti-thrombotic in antiphospholipid syndrome

Elective therapeutic approaches are required since recurrent thrombosis remains a major challenge in the management of antiphospholipid syndrome (APS) despite an efficient anticoagulation. Several data suggest that hydroxychloroquine (HCQ) could play a role in the prevention of thrombosis. The goal of this review is to point out the different aspects that could suggest the usefulness and the efficacy of HCQ for the prevention of thrombosis relapse in APS. By Medline research we collected important data dealing with potential anti-thrombotic effects of HCQ. The mechanisms of action of HCQ, and clinical and experimental data in systemic lupus erythematosus (SLE) and APS are discussed. As HCQ reduces the risk of thrombosis in both SLE patients and animal models of APS (1-7), and possibly decreases the titre of aPL [8], its beneficial role as a potential antithrombotic could be suggested.

Bridging therapy in antiphospholipid syndrome and antiphospholipid antibodies carriers: case series and review of the literature

Peri-operative management of patients on warfarin involves assessing and balancing individual risks for thromboembolism and bleeding. The timing of warfarin withdrawal and a tailored pre/postoperative management (including the substitution of heparin in place of warfarin, the so-called bridging therapy) is critical in patients with prothrombotic conditions. The antiphospholipid syndrome (APS) is the most common cause of acquired thrombophilia. In this particular subset of patients, as the risk of thrombosis is higher than in general population, bridging therapy can represent a real challenge for treating physicians. Only few studies have been designed to address this topic. We aim to report our experience and to review the available literature in the peri-procedural management of APS and antiphospholipid antibody-positive patients, reporting adverse events and attempting to identify potential risk factor associated with thrombosis or bleeding complications.