Antiphospholipid syndrome: an update

Stroke risk in multiple sclerosis: a critical appraisal of the literature

Observational studies suggest that the occurrence of stroke on multiple sclerosis (MS) patients is higher compared to the general population. MS is a heterogeneous disease that involves an interplay of genetic, environmental and immune factors. The occurrence of stroke is subject to a wide range of both modifiable and non-modifiable, short- and long-term risk factors. Both MS and stroke share common risk factors. The immune mechanisms that underlie stroke are similar to neurodegenerative diseases and are attributed to neuroinflammation. The inflammation in autoimmune diseases may, therefore, predispose to an increased risk for stroke or potentiate the effect of conventional stroke risk factors. There are, however, additional determinants that contribute to a higher risk and incidence of stroke in MS. Due to the challenges that are associated with their differential diagnosis, the objective is to present an overview of the factors that may contribute to increased susceptibility or occurrence of stroke in MSpatients by performing a review of the available to date literature. As both MS and stroke can individually detrimentally affect the quality of life of afflicted patients, the identification of factors that contribute to an increased risk for stroke in MS is crucial for the prompt implementation of preventative therapeutic measures to limit the additive burden that stroke imposes.

Anticardiolipin from Periodontitis Patients Impact Fetal Loss and Annexin V

Anticardiolipin antibodies, found at elevated serum concentrations in 15% to 20% of individuals with periodontitis, are associated with adverse pregnancy outcomes, thrombotic conditions, and accelerated atherosclerosis in autoimmune disease such as the antiphospholipid syndrome. Our previous studies demonstrated that antibodies raised in mice against Porphyromonas gingivalis caused fetal loss in a mouse pregnancy model due to anticardiolipin antibodies. Such antibodies are induced via molecular mimicry with the serum protein β2-glycoprotein 1 (β2GP1), the target antigen of anticardiolipin. Furthermore, human anticardiolipin IgG is associated with increased serum markers of vascular inflammation, and IgG purified from periodontitis subjects with elevated anticardiolipin stimulates inflammatory cytokine production by endothelial cells and a trophoblastic cell line. Activation of the trophoblastic cells by anticardiolipin occurs through Toll-like receptor 4. In the present study, we observed that IgG anticardiolipin from periodontitis subjects also causes fetal loss in mice. Displacement of the protective 2-dimensional lattice formed by annexin V on trophoblast surfaces by anticardiolipin, via its interaction with its target antigen β2GP1, leading to fibrin clot formation due to exposure of anionic phospholipids to plasma, is a plausible pathogenic mechanism explaining adverse obstetrical outcomes in antiphospholipid syndrome. Therefore, we assessed such interactions in periodontitis. We observed that anticardiolipin from periodontitis subjects competes for annexin V on an artificial phosphatidylserine monolayer, replicating a key activity of autoantibodies found in patients with antiphospholipid syndrome. In addition, we found that anticardiolipin from periodontitis subjects increases annexin V levels on the BeWo choriocarcinoma cell line, consistent with mobilization of annexin V to the cell surface to facilitate repair following membrane damage. The data indicate that sera and IgG from periodontitis subjects with elevated anticardiolipin levels may influence pregnancy outcomes due to interactions with annexin V.

Correlation between Osteoprotegerin Levels and Antiphospholipid Syndrome Parameters

OBJECTIVE

To identify the osteoprotegerin (OPG) correlates with antiphospholipid syndrome (APS) parameters.

METHODS

Our cohort included 40 patients with primary APS disease associated with systemic lupus erythematosus (SLE) (mean age, 43.7 years; 87% female). Data on cardiovascular risk factors and specific clinical events in APS were collected. Then we tested OPG and 10 criteria and noncriteria antiphospholipid antibodies (aPLs) on preserved specimens in all cases.

RESULTS

A total of 26 patients (65%) had high serum OPG levels. Patients with high OPG were mostly overweight. In patients with SLE, the OPG levels were associated with anti-double-stranded DNA (anti-dsDNA) and anti-Sm titers. However, we did not find significant correlations of the OPG with any of the 10 aPLs tested. Also, we found no relationship regarding venous APS events.

CONCLUSION

In APS, high OPG levels are not linked to serum aPL expression.

Acute ST-elevation myocardial infarction in a young patient with antiphospholipid syndrome

Acute coronary syndrome rarely occurs in young individuals and is seldomly associated with antiphospholipid syndrome. We report the case of a 26-year-old Hispanic man who presented with acute ST-elevation myocardial infarction and was treated with urgent percutaneous transluminal coronary angioplasty. He experienced stent thrombosis within 48 h of intervention and subsequently developed a left apical thrombus. Hypercoagulable state studies were obtained at admission and 12 weeks after the event establishing the diagnosis of antiphospholipid syndrome.

The Solitary Blue Toe: A Unique Presentation of Antiphospholipid Syndrome

Antiphospholipid syndrome is an autoimmune disease characterized by vascular thrombosis involving both the arterial and venous systems that can lead to tissue ischemia or end-organ damage. Much of the literature describes various symptoms at initial presentation, but isolated tissue ischemia manifesting as a solitary blue toe is unusual. We discuss a case of a 23-year-old man who presented to the emergency department with a solitary blue fourth digit with minimal erythema and edema, who was suffering from exquisite pain. Following an extensive workup, the patient was diagnosed with antiphospholipid syndrome with thrombi of the vasculature in their lower extremity. With therapeutic anticoagulation, the patient's symptoms subsided and amputation of the digit was prevented.

Antiphospholipid Antibodies Overlapping in Isolated Neurological Syndrome and Multiple Sclerosis: Neurobiological Insights and Diagnostic Challenges

Antiphospholipid syndrome (APS) is characterized by arterial and venous thrombosis, pregnancy morbidity and fetal loss caused by pathogenic autoantibodies directed against phospholipids (PL) and PL-cofactors. Isolated neurological APS may represent a significant diagnostic challenge, as epidemiological, clinical and neuroimaging features may overlap with those of multiple sclerosis (MS). In an open view, MS could be considered as an organ-specific anti-lipid (phospholipid and glycosphingolipid associated proteins) disease, in which autoreactive B cells and CD8+ T cells play a dominant role in its pathophysiology. In MS, diverse autoantibodies against the lipid-protein cofactors of the myelin sheath have been described, whose pathophysiologic role has not been fully elucidated. We carried out a review to select clinical studies addressing the prevalence of antiphospholipid (aPL) autoantibodies in the so-called MS-like syndrome. The reported prevalence ranged between 2% and 88%, particularly aCL and aβ2GPI, with predominant IgM isotype and suggesting worse MS prognosis. Secondarily, an updated summary of current knowledge on the pathophysiological mechanisms and events responsible for these conditions is presented. We draw attention to the clinical relevance of diagnosing isolated neurological APS. Prompt and accurate diagnosis and antiaggregant and anticoagulant treatment of APS could be vital to prevent or at least reduce APS-related morbidity and mortality.

Presence of Immune Complexes of IgG/IgM Bound to B2-glycoprotein I Is Associated With Non-criteria Clinical Manifestations in Patients With Antiphospholipid Syndrome

Background: Antiphospholipid syndrome (APS) is an acquired autoimmune disorder defined by the presence of both clinical (thromboembolic events or pregnancy morbidity) and laboratory (antiphospholipid antibodies, aPL) manifestations. Despite their importance, several clinical manifestations strongly associated with APS such as livedo reticularis (LR), thrombocytopenia, sicca-ophthalmic(sicca), heart, or neurological manifestations are not included in the APS clinical classification criteria. Circulating immune complexes (CIC) formed by Beta-2-glycoprotein I (B2GPI) and aPL (B2-CIC) have been described and their presence has been related with thrombotic events.

Methods: Cross-sectional and observational cohort study in APS patients with thrombotic symptomatology.

Setting and Participants: Fifty-seven patients from the University Hospital Center Bezanijska Kosa (Belgrade, Serbia) who met the APS classification criteria (35 with primary APS and 22 with APS associated to systemic lupus erythematosus). This study aimed to determine the prevalence of B2-CIC in APS patients and to evaluate their association with clinical manifestations of APS not included in the classification criteria.

Results: B2-CIC prevalence in APS patients was 19.3%. The presence of thrombocytopenia (OR:5.7), livedo reticularis (OR:5.6), sicca (OR:12.6), and leukopenia (OR:5.6) was significantly higher in patients with B2-CIC than in the rest of APS patients. C3 and C4 complement factor levels were significantly lower in B2-CIC positive patients, which suggests a greater consumption of complement. Patients with quadruple aPL positivity (triple aPL-positivity plus the presence of B2-CIC) showed a higher prevalence of thrombocytopenia, leucopenia and LR than those with single/double aPL-positivity. No significant differences were found in the frequencies observed in patients with triple-only vs. single/double aPL-positivity. There were no significant differences between patients with primary APS and lupus-associated APS regarding the prevalence of B2-CIC and outcomes.

Conclusions: Presence of B2-CIC is strongly associated with several non-criteria clinical manifestations related to APS and to higher complement consumption. More studies are required to better understand the clinical significance of B2-CIC.

HIBISCUS: Hydroxychloroquine for the secondary prevention of thrombotic and obstetrical events in primary antiphospholipid syndrome

The relapse rate in antiphospholipid syndrome (APS) remains high, i.e. around 20%-21% at 5 years in thrombotic APS and 20-28% in obstetrical APS [2, 3]. Hydroxychloroquine (HCQ) appears as an additional therapy, as it possesses immunomodulatory and anti-thrombotic various effects [4-16]. Our group recently obtained the orphan designation of HCQ in antiphospholipid syndrome by the European Medicine Agency. Furthermore, the leaders of the project made the proposal of an international project, HIBISCUS, about the use of Hydroxychloroquine in secondary prevention of obstetrical and thrombotic events in primary APS. This study has been launched in several countries and at now, 53 centers from 16 countries participate to this international trial. This trial consists in two parts: a retrospective and a prospective study. The French part of the trial in thrombosis has been granted by the French Minister of Health in December 2015 (the academic trial independent of the pharmaceutical industry PHRC N PAPIRUS) and is coordinated by one of the members of the leading consortium of HIBISCUS.

Primary antiphospholipid syndrome and antiphospholipid syndrome associated to systemic lupus: Are they different entities?

Primary antiphospholipid syndrome (PAPS) and antiphospholipid syndrome associated to lupus (SAPS) have several overlapping characteristics. As systemic manifestations are also reported in patients with PAPS, and as a subgroup of PAPS patients could evaluate to a SAPS, the differentiation between the two types of APS could be performed based on the clinical experience of the medical teams and is related to a variety of clinical, biological, histological and genetic features. Several data are available in the literature with respect to the identification of distinctive features between these two entities. However, there are some limitation in the interpretation of results issued from studies performed prior to updated Sydney criteria. Based on recent data, a certain number of features more frequent in one type of APS as compared to the other could be distinguished. The major differentiation between these two entities is genetical. New genetic data allowing the identification of specific subgroups of APS are ongoing.

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.

A importância de reconhecer a síndrome antifosfolípide na medicina vascular

A síndrome antifosfolipíde (SAF) é uma doença autoimune sistêmica caracterizada por trombose arterial ou venosa recorrente e/ou morbidade gestacional e pela presença dos anticorpos antifosfolipídeos, podendo apresentar outras manifestações vasculares, como microangiopatia, arteriopatia crônica e SAF catastrófica. Determinados testes laboratoriais para a síndrome (por exemplo, o anticoagulante lúpico) podem sofrer interferência do uso de medicações anticoagulantes, dificultando o diagnóstico. A fisiopatologia da SAF é complexa, sendo enumerados no texto diversos mecanismos patogênicos relacionados à coagulação, ao endotélio e às plaquetas. Por fim, discutimos o tratamento da SAF de acordo com a presença e o tipo de manifestações clínicas, o uso dos anticoagulantes orais diretos e o manejo perioperatório de pacientes com SAF.

What is known about pediatric antiphospholipid syndrome?

INTRODUCTION

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by vascular thrombosis and/or pregnancy morbidity associated with the persistent presence of antiphospholipid antibodies (aPL) including lupus anticoagulant (LA), anticardiolipin antibodies (aCL), and anti-β2 glycoprotein I antibodies (aβ2GPI).

AREAS COVERED

APS is considered as the most common acquired hypercoagulation state of autoimmune origin in children. Unfortunately, data about incidence, prevalence, thrombosis risk and effective treatment in paediatric APS are limited and unmethodical. Expert commentary: This review summarizes recent clinical, laboratory and therapy characterization of paediatric APS and emphasizes the differences between paediatric and adult populations.

Hughes syndrome and epilepsy: when to test for antiphospholipid antibodies?

Epilepsy and seizures are reported among the neurological manifestations of antiphospholipid syndrome (APS) at a prevalence rate of approximately 8%, which is nearly 10 times the prevalence of epilepsy in the general population. The association of seizures with antiphospholipid antibodies (aPL) is even more significant in the presence of systemic lupus erythematosus (SLE). In this review, we discuss the epidemiological, pathophysiological, laboratory, clinical, and radiological aspects of this association, and derive suggestions on when to consider testing for aPL in epileptic patients and how to manage seizures secondary to APS based on literature data. Epilepsy due to APS should be considered in young patients presenting with seizures of unknown origin. Temporal lobe epilepsy seems to be particularly prevalent in APS patients. The pathogenesis is complex and may not only involve micro-thrombosis, but also a possible immune-mediated neuronal damage. Patients with seizures and positive aPL tend to develop thrombocytopenia and livedo racemosa more frequently compared with those without aPL. Magnetic resonance imaging (MRI) remains the imaging modality of choice in these patients. The presence of SLE and the presence of neurological symptoms significantly correlate with the presence of white matter changes on MRI. In contrast, the correlation between aPL positivity and the presence of white matter changes is very weak. Furthermore, MRI can be normal in more than 30–40% of neuropsychiatric lupus patients with or without aPL. aPL testing is recommended in young patients presenting with atypical seizures and multiple hyper-intensity lesions on brain MRI in the absence of other possible conditions. New MRI techniques can better understand the pathology of brain damage in neuro-APS. The therapeutic management of epileptic APS patients relies on anti-epileptic treatment and anticoagulant agents when there is evidence of a thrombotic event. In the absence of consensual recommendations, the decision of lifelong anticoagulation is discussed on a case-by-case basis. The anti-thrombotic benefit of hydroxychloroquine and statins is supported by several studies.

Antiphospholipid Antibodies: Their Origin and Development

Antiphospholipid antibodies (aPL) are a hallmark of the antiphospholipid syndrome (APS), which is the most commonly acquired thrombophilia. To date there is consensus that aPL cause the clinical manifestations of this potentially devastating disorder. However, there is good evidence that not all aPL are pathogenic. For instance, aPL associated with syphilis show no association with the manifestations of APS. While there has been intensive research on the pathogenetic role of aPL, comparably little is known about the origin and development of aPL. This review will summarize the current knowledge and understanding of the origin and development of aPL derived from animal and human studies.

Musculoskeletal manifestations of the antiphospholipid syndrome

The scope of clinical and laboratory manifestations of the antiphospholipid syndrome (APS) has increased dramatically since its discovery in 1983, where any organ system can be involved. Musculoskeletal complications are consistently reported in APS patients, not only causing morbidity and mortality, but also affecting their quality of life. We reviewed all English papers on APS involvement in the musculoskeletal system using Google Scholar and Pubmed; all reports are summarized in a table in this review. The spectrum of manifestations includes arthralgia/arthritis, avascular necrosis of bone, bone marrow necrosis, complex regional pain syndrome type-1, muscle infarction, non-traumatic fractures, and osteoporosis. Some of these manifestations were reported in good quality studies, some of which showed an association between aPL-positivity and the occurrence of these manifestations, while others were merely described in case reports.