Diagnostic biologique du syndrome des antiphospholipides : des critères à la pratique

[How to interpret and pursue a prolonged quick time or APTT]

The standard hemostasis workup [quick time (QT), and activated partial thrombin time (APTT)] is very commonly prescribed but its interpretation is often difficult for practitioners who are not specialized in hemostasis. Here, we review the principles of the diagnostic approach to these tests. Only a very basic knowledge of the coagulation cascade is necessary to identify which clotting factor tests to prescribe and to interpret the results. Deficiency in several clotting factors suggests liver dysfunction, disseminated intravascular coagulation (DIC) or vitamin K deficiency. If a single factor is deficient, we review the different causes of acquired deficiencies and briefly discuss the characteristics of the different congenital defects, which generally require specialized management. Lupus anticoagulant is a common and generally benign cause of prolonged APTT to be aware of, which is not related to a hemorrhagic risk. A good knowledge of the diagnostic approach to abnormal QT or APTT generally allows the resolution of the most common situations.

French National Diagnostic and Care Protocol for antiphospholipid syndrome in adults and children

Antiphospholipid syndrome (APS) is a chronic autoimmune disease involving vascular thrombosis and/or obstetric morbidity and persistent antibodies to phospholipids or certain phospholipid-associated proteins. It is a rare condition in adults and even rarer in children. The diagnosis of APS can be facilitated by the use of classification criteria based on a combination of clinical and biological features. APS may be rapidly progressive with multiple, often synchronous thromboses, resulting in life-threatening multiple organ failure. This form is known as "catastrophic antiphospholipid syndrome" (CAPS). It may be primary or associated with systemic lupus erythematosus (associated APS) and in very rare cases with other systemic autoimmune diseases. General practitioners and paediatricians may encounter APS in patients with one or more vascular thromboses. Because APS is so rare and difficult to diagnosis (risk of overdiagnosis) any suspected case should be confirmed rapidly and sometimes urgently by an APS specialist. First-line treatment of thrombotic events in APS includes heparin followed by long-term anticoagulation with a VKA, usually warfarin. Except in the specific case of stroke, anticoagulants should be started as early as possible. Any temporary discontinuation of anticoagulants is associated with a high risk of thrombosis in APS. A reference/competence centre specialised in autoimmune diseases must be urgently consulted for the therapeutic management of CAPS.

[Contribution of antiphosphatidylserine/prothrombin (anti-PS/PT) antibody detection in the diagnosis and management of antiphospholipid syndrome (APS)]

Antiphospholipid syndrome (APS) is an autoimmune disease and one of the most common causes of acquired thrombophilia. It is characterised by the occurrence of thrombotic or obstetric events associated with the presence of persistent antiphospholipid antibodies. The diagnosis can be challenging, particularly because some biological tests can be disturbed by anticoagulant treatment or inflammation. In the recent years, new antiphospholipid antibodies, including anti-phosphatidylserine/prothrombin antibodies (anti-PS/PT), have emerged but their clinical significance and causality remain uncertain. Biologically, several studies have found a strong correlation between the presence of lupus anticoagulant (LA) and anti-PS/PT antibodies. Clinically, the presence of anti-PS/PT antibodies is associated with an increased risk of thrombosis and obstetric complications. There is also an association with thrombocytopenia, suggesting that the presence of anti-PS/PT antibodies may be associated with more severe clinical APS. Among seronegative APS patients, 6-17% of patients are positive for anti-PS/PT antibodies. This might influence the therapeutic management of patients. This article aims to provide an update on contribution of anti-PS/PT antibodies detection for the diagnosis and management of APS.

Antiphospholipid antibodies in the obstetric antiphospholipid syndrome: Detection and antibodies profile at the Maternity and Neonatal Medicine Center of Monastir, Tunisia

PURPOSE

This study aimed to implement lupus anticoagulant (LAC) detection techniques according to the International Society on Thrombosis and Hemostasis (ISTH) recommendations, in the Biological Laboratory of the Maternity and Neonatal Medicine Center (Monastir, Tunisia) and to evaluate the profile and the prevalence of antiphospholipid antibodies (aPL) in the obstetric antiphospholipid syndrome (OAPS).

METHODS

We collected two groups: a "case group" (53 women who presented one or more obstetrical criteria of APS) and a "control group." LAC was detected following the four steps recommended by ISTH 2009. Anticardiolipin (aCL) and antibeta-2-glycoprotein I (aβ2GPI) antibodies testing were performed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

aPL were found in five patients: three patients with isolated LAC, one patient with isolated IgG aCL, and one patient with triple positivity (LAC, aCL IgM, aβ2GPI IgM). Concerning LAC, 13 (24.52%) of 53 patients had a screening step with at least one positive test. The mixing step was positive in four patients and then confirmed in the confirmatory test. Thus, the prevalence of LAC in our study group is 7.54%. Surprisingly, among these positive patients, one patient had an associated combined factor V (FV) and factor VIII (FVIII) deficiency.

CONCLUSION

There is no single test and no algorithm that can detect all types of LAC. It seems that the recent 2020 ISTH algorithm allows a better detection of low activity LAC than the 2009 algorithm. In our study, the most frequently identified antiphospholipid antibodies were LAC more than aCL and aβ2GPI.

Recent Advances in Anticoagulant Treatment of Immune Thrombosis: A Focus on Direct Oral Anticoagulants in Heparin-Induced Thrombocytopenia and Anti-Phospholipid Syndrome

For more than 10 years, direct oral anticoagulants (DOACs) have been increasingly prescribed for the prevention and treatment of thrombotic events. However, their use in immunothrombotic disorders, namely heparin-induced thrombocytopenia (HIT) and antiphospholipid syndrome (APS), is still under investigation. The prothrombotic state resulting from the autoimmune mechanism, multicellular activation, and platelet count decrease, constitutes similarities between HIT and APS. Moreover, they both share the complexity of the biological diagnosis. Current treatment of HIT firstly relies on parenteral non-heparin therapies, but DOACs have been included in American and French guidelines for a few years, providing the advantage of limiting the need for treatment monitoring. In APS, vitamin K antagonists are conversely the main treatment (+/− anti-platelet agents), and the use of DOACs is either subject to precautionary recommendations or is not recommended in severe APS. While some randomized controlled trials have been conducted regarding the use of DOACs in APS, only retrospective studies have examined HIT. In addition, vaccine-induced immune thrombotic thrombocytopenia (VITT) is now a part of immunothrombotic disorders, and guidelines have been created concerning an anticoagulant strategy in this case. This literature review aims to summarize available data on HIT, APS, and VITT treatments and define the use of DOACs in therapeutic strategies.

Anti-Phosphatidylserine/Prothrombin Antibodies at Two Points: Correlation With Lupus Anticoagulant and Thrombotic Risk

Antibodies to phospholipids (aPL) and associated proteins are a hallmark in the diagnosis of anti-phospholipid syndrome (APS). Those included in the classification criteria are the lupus anticoagulant (LA) and the IgG and IgM isotypes of anticardiolipin (aCL) and anti-beta-2 glycoprotein I (β2GPI) antibodies. Non-classification criteria markers such as autoantibodies that recognize the phosphatidylserine/prothrombin (aPS/PT) complex have been proposed as biomarkers for APS. Studies of aPS/PT antibodies have shown a strong correlation to clinical manifestations and LA. We aimed to study the value and the persistence of aPS/PT IgG and IgM antibodies in a cohort of consecutive patients with clinical suspicion of APS and their utility as thrombotic risk markers. Our study, with 103 patients, demonstrates that persistently positive results for aPS/PT IgG antibodies were significantly associated with APS classification, thrombosis, triple aPL positivity, LA positive result, and the Global APS Score (GAPSS) > than 9 points (p < 0.01, for each condition). On the other hand, no association was seen with pregnancy morbidity (p = 0.56) and SLE (p = 0.07). Persistence of aPS/PT antibodies, defined according to the current laboratory classification criteria, likely improves the diagnosis and clinical assessment of patients with APS.

[COVID-19: Coagulopathy and thrombosis]

Le virus SARS-CoV-2 a provoqué une pandémie mondiale en quelques semaines, causant l’infection de plus de 20 millions de sujets. Près du 15 % des patients atteints de la maladie à coronavirus 2019 (COVID-19) et plus de 70 % des formes graves présentent des anomalies de coagulation. Cet état « d’hypercoagulabilité » incluant essentiellement une élévation marquée des D-Dimères est associé à un risque accru de décès. En outre, une proportion substantielle de patients atteints de COVID-19 sévère développent des complications thromboemboliques veineuses, incidence d’autant plus élevée que les patients sont admis en unités de soins intensifs ou en réanimation. Une meilleure compréhension de la physiopathologie de la COVID-19, en particulier des troubles de l’hémostase, permettra d’adapter des stratégies thérapeutiques, notamment anti-thrombotiques. La mise en évidence de ces anomalies doit être associée à une évaluation rigoureuse du risque thrombotique permettant la mise en place d’une stratégie anti-thrombotique adaptée. Nous passons en revue les caractéristiques des données biologiques de la « coagulopathie » associée à la COVID-19, l’incidence des événements thromboemboliques et leurs spécificités ainsi que les interventions thérapeutiques potentielles.

[Libman-Sacks endocarditis under apixaban in a patient with a high-risk profile venous antiphospholipid syndrome]

INTRODUCTION

Libman-Sacks endocarditis is a rare complication of antiphospholipid syndrome. Anti-vitamin K therapy is the standard treatment, although valvular replacement surgery may be required in some severe cases. In the latest EULAR recommendations, it is advised not to use direct oral anticoagulants in the management of antiphospholipid syndrome, especially of high-risk profile.

CASE REPORT

We present a case of a mitral Libman-Sacks endocarditis complicated with multiple strokes occurring in the setting of an antiphospholipid syndrome with triple positive antibody profile in a 63-year-old woman with multiple sclerosis. She was previously treated with apixaban for two years. Tinzaparin followed by prolonged warfarine treatment and two months of hydroxychloroquine resulted in valvular improvement.

CONCLUSION

To our knowledge, this is the first case of Libman-Sacks endocarditis occurring during apixaban therapy in a patient with antiphospholipid syndrome. This severe case highlights the inefficiency of direct oral anticoagulants to prevent thrombotic events in the antiphospholipid syndrome.

[Seronegative antiphospholipid syndrome: Myth or reality?]

The antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by thrombosis and/or obstetrical manifestations and the persistent presence, at least 12 weeks apart, of antiphospholipid antibodies (aPL) such as lupus anticoagulant (LA) and/or anticardiolipin antibodies (ACL) and/or anti-β2 glycoprotein I antibodies (aβ2GPI). The finding of patients with clinical profile highly suggestive of APS but who are negative for conventional biological criteria has led to the concept of seronegative APS. In the last few years, new antigen targets and methodological approaches have been employed to more clearly identify this syndrome in patients with thrombosis or obstetrical complications without conventional aPL. Although seronegative APS is still controversial, there is increasing recognition of the existence of this subgroup. However, clinical relevance of non conventional aPL need to be confirmed by efforts toward standardizing new biological tools and longitudinal studies involving large cohort of patients.

[Bilateral adrenal hemorrhage under apixaban in primary antiphospholipid syndrome]

INTRODUCTION

Adrenal hemorrhage is a classical but rare complication of antiphospholipid syndrome, revealing diagnosis in one third of the cases. Anti-vitamin K therapy is the standard treatment but direct oral anticoagulants are discussed as an alternative. In the latest recommendations, it is advised not to use direct oral anticoagulants in the setting of antiphospholipid syndrome.

CASE REPORT

We present a case of bilateral adrenal hemorrhage revealing primary antiphospholipid syndrome with triple positive antibody profile, in a 47-year-old man treated by apixaban for previous venous thromboembolism.

CONCLUSION

To our knowledge, it is the first case of adrenal hemorrhage occurring during apixaban treatment in a patient with antiphospholipid syndrome. This case illustrates the inefficacy of direct oral anticoagulants to prevent thrombotic events in antiphospholipid syndrome, in accordance with the latest recommendations.

[Which place of antiphosphatidylethanolamine antibodies research in seronegative antiphospholipid syndrome suspicion?]

PURPOSE

Antiphospholipid syndrome (APS) is a clinico-biological syndrome, which associates vascular injury and persisting antiphospholipid antibodies (aPL). Patients with clinical symptoms of APS but without aPL are defined as "seronegative APS" (SNAPS). The aim of this study was to evaluate antiphosphatidylethanolamine antibody (aPE) investigation in patients with SNAPS suspicion.

METHODS

This retrospective study was conducted in patients with SNAPS suspicion. A homemade enzyme-linked immunosorbent assay (ELISA) was used to search for aPE. The results of this homemade method were compared with those from a global screening ELISA.

RESULTS

Two hundred twenty-eight patients with SNAPS suspicion were included. Among them, 58.3% had a thrombotic event. The homemade ELISA found positive persisting aPE in 23 patients (10%): 15 with a thrombotic event, 6 with obstetrical morbidity and 2 with a combined event. The global screening ELISA was positive in only 11 of these 23 patients (47.8%).

CONCLUSION

These results suggest the implication of aPE in SNAPS.

[Hemorrhagic syndrome due to a heparin-like anticoagulant in a patient with systemic lupus erythematosus]

INTRODUCTION

In systemic lupus erythematosus, hemostasis disorders are mainly thrombotic, but more rarely hemorrhagic.

CASE REPORT

A 25-year-old man presented with a macrophagic activation syndrome revealing a systemic lupus erythematosus, secondarily complicated by a hemorrhagic syndrome ; biological investigations revealed an increase thrombin time and an activated partial thromboplastin time, normalized by protamin neutralization in vitro, thus confirming the presence of a heparin-like anticoagulant. The hemostasis balance normalized after the specific treatment of lupus.

CONCLUSION

This rare anomaly of hemostasis balance has been described in blood cancers and solid cancers. This is the first description of a case associated with an autoimmune connective tissue disorder such as lupus. After one year of follow-up, no diagnosis of blood or solid cancer was made.