Diagnosis and management of the antiphospholipid syndrome

S-hydroxychloroquine prevents the antiphospholipid thrombogenic complexes for antiphospholipid syndrome treatment

Clinically used in systemic lupus erythematosus (SLE), Hydroxychloroquine (HCQ) exerts antithrombotic effects by inhibiting anti-β2-glycoprotein I (anti-β2GPI) antibody binding to phospholipid bilayers. However, HCQ is a racemic mixture, with only one enantiomer offering therapeutic benefits, while the other may contribute to toxicity. The current study evaluated the thromboprophylactic efficacy of R-enantiomer Hydroxychloroquine (R-HCQ), S-enantiomer Hydroxychloroquine (S-HCQ), and racemic HCQ (Rac-HCQ), with a focus on their impact on APS-associated markers. Both in vitro and in vivo models were employed, with human umbilical vein endothelial cells (HUVECs) and mice immunized with human β2-glycoprotein I antibodies used to evaluate the formation of antiphospholipid thrombotic complexes and their modulation by HCQ enantiomers. S-HCQ significantly reduced β2GPI complex binding and restored the AnxA5 anticoagulant shield in vitro, demonstrating superior efficacy over R-HCQ in disrupting β2GPI/anti-β2GPI interactions and preventing endothelial dysfunction in APS models. Pretreatment of HUVECs with S-HCQ significantly attenuated the expression of proinflammatory cytokines (tumor necrosis factor-alpha, interleukin-6, interleukin-1 beta, and C-C motif ligand 2) and endothelial activation markers (intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin). S-HCQ alleviates endothelial dysfunction by reducing proinflammatory cytokines, endothelial activation markers, and NO production while downregulating iNOS expression, highlighting its potential to mitigate oxidative stress and thrombogenic activity in APS-related endothelial damage. In vivo, S-HCQ effectively reduced clot formation in the femoral veins of APS mouse models. Among the HCQ enantiomers tested, S-HCQ demonstrated superior efficacy in modulating inflammatory and angiogenic pathways, influencing the formation of antiphospholipid thrombotic complexes and mitigating thrombosis. These findings underscore the potential of S-HCQ as a therapeutic alternative for APS management.

Remnant cholesterol predicts risk of recurrent thrombosis beyond LDL-cholesterol in patients with antiphospholipid syndrome

BACKGROUND

Antiphospholipid syndrome (APS) is notably linked to thrombotic events, particularly cardiovascular disease (CVD). The role of remnant cholesterol (RC) in predicting CVD risk is established, yet its relationship with thrombotic risk in APS patients remains to be elucidated. This study aims to assess the association between RC and recurrent thrombotic risk in patients with APS.

METHODS

A prospective analysis was conducted based on a cohort of APS patients who met the 2006 Sydney revised classification criteria. Thrombotic risks associated with varying levels of RC were evaluated using Kaplan-Meier survival analysis and Cox proportional hazards regression models. Mendelian randomization (MR) was applied to examine the causal link between RC and different types of thrombotic events.

RESULTS

A total of 325 patients with APS were enrolled in this study. Over a median follow-up of 35 months, 51 patients experienced thrombotic events, including 24 venous, 19 arterial, and 16 microvascular incidents. Patients with RC levels above 0.60 mmol/L exhibited significantly higher risks, with multivariable-adjusted hazard ratio (and 95% confidence interval) for all-cause, venous, arterial thrombosis, and microvascular disease being 5.05 (2.23-11.41), 6.34 (1.71-23.54), 3.79 (1.00-14.32), and 4.36 (1.08-17.58), respectively. Notably, elevated RC remained a significant thrombotic risk factor even in patients with normal conventional lipid profiles. MR analysis revealed a significant causal association between RC and arterial thrombosis, but not venous thrombosis.

CONCLUSIONS

Elevated RC is linked to a substantial increase in the risk of thrombotic events in APS patients. These findings suggest that RC could be a valuable marker for thrombotic risk in this population and a potential target for therapeutic intervention.

Update on the Laboratory Diagnosis of Lupus Anticoagulant: Current Challenges and Clinical Involvement

Lupus anticoagulant (LAC) is a heterogeneous mix of autoimmune antibodies that prolongs phospholipid-dependent clotting assays. Its diagnosis can be a real challenge in the hemostasis laboratory. In this review, the author describes the main pitfalls affecting the preanalytical phase and how to proceed to reduce interferences. Because of the heterogeneity of these autoantibodies, two assays with different mechanism of action should be performed to detect the majority of LACs. The dilute Russell's viper venom test and the use of a reagent very sensitive to LAC derived from the activated partial thromboplastin time, using silica as the activator, are the most frequent techniques. The algorithms for LAC detection are reported here, and every laboratory is encouraged to introduce its own diagnostic procedure. Results should be expressed in ratio to reduce inter- and intravariability. In addition, the effect of anticoagulation in LAC assays and possible strategies for a correct diagnosis are provided.

Antiphospholipid syndrome in pregnancy: a comprehensive literature review

BACKGROUND

Antiphospholipid syndrome (APS) is an autoimmune disorder associated with thrombotic events and adverse obstetric outcomes, particularly in its obstetric form (OAPS). Affecting approximately 0.5% of the population, APS is a leading contributor to recurrent pregnancy loss (RPL), preeclampsia (PE), and fetal growth restriction ((FGR). Despite advancements in understanding its pathophysiology and management, optimal treatment strategies for APS in pregnancy remain challenging and require systematic evaluation. This review synthesizes current evidence on APS mechanisms, diagnostic criteria, and therapeutic interventions, with a focus on maternal and fetal outcomes in OAPS.

METHODS

A comprehensive search of PubMed, was conducted to identify studies exploring APS pathogenesis, diagnostic standards, and treatment efficacy in obstetric settings. Inclusion criteria prioritized randomized controlled trials, cohort studies, and systematic reviews with a clear focus on APS and pregnancy.

RESULTS

The review confirmed that APS current accepted pathogenesis is governed by a "two-hit" model, where antiphospholipid antibodies (aPLs) initiate endothelial damage, culminating in thrombosis and placental insufficiency. Epidemiological analysis underscores the prevalence and severity of APS in obstetric contexts, with lupus anticoagulant (LA) emerging as a significant predictor of adverse outcomes. Evidence supports the use of low-dose aspirin (LDA) and heparin to reduce miscarriage rates, while adjunctive treatments, such as hydroxychloroquine (HCQ), have shown promise in improving live birth rates and reducing preterm delivery in high-risk cases. Emerging therapies, including tumoral necrosis factor (TNF-alpha) inhibitors and nitric oxide modulators, may offer additional benefits in refractory cases.

CONCLUSION

APS remains a critical determinant of adverse pregnancy outcomes, necessitating precise diagnostic criteria and tailored management approaches. This systematic review emphasizes the importance of individualized therapeutic regimens to optimize maternal and fetal health in OAPS and highlights areas for future research, particularly regarding novel pharmacological approaches. Further studies are essential to refine treatment protocols and improve clinical guidelines for managing APS in pregnancy.

Antiphospholipid syndrome in pregnancy: A comprehensive review

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by the presence of antiphospholipid antibodies and is associated with thrombotic events and pregnancy complications. The classification and management of APS has evolved over time. The classification criteria for APS include laboratory, macrovascular, microvascular, obstetric, cardiac, and hematologic domains. Management focuses on prevention of thrombotic events and/or anticoagulation as the primary treatment for thrombosis. Postpartum and long-term thromboprophylaxis after delivery are recommended to reduce the risk of thrombotic events. Despite these recommendations, optimal anticoagulation agents and intensity of treatment are still topics of debate. Further research is needed to understand the pathophysiology of APS and improve its management during pregnancy. In this review, we discuss the classification and pathophysiology of APS. Current treatment options and clinical trials are also discussed.

Navigating antiphospholipid syndrome: from personalized therapies to cutting-edge research

APS is an autoimmune disorder characterized by thrombosis and pregnancy complications, primarily driven by aPLs such as LA, aCL and anti-β2 glycoprotein I (a-β2GPI). Despite advances in anticoagulation therapies, managing refractory APS cases remains challenging. Emerging therapies, including rituximab, eculizumab and HCQ, show potential in addressing the underlying mechanisms of APS. Additionally, research into genetic and environmental factors, particularly the gut microbiome's role through molecular mimicry, suggests new therapeutic pathways. Diagnostic advancements, such as the adjusted Global Antiphospholipid Syndrome Score (aGAPSS), metabolomic profiling and MRI, have improved risk stratification and early detection. Non-traditional biomarkers like anti-phosphatidylserine/prothrombin (aPS/PT) and anti-Domain I antibodies further enhance risk assessment. Future research should aim to validate these approaches, optimizing patient outcomes and minimizing long-term APS complications.

Pierre Y, Skeith L. Non-criteria antiphospholipid antibody profiles and thrombotic outcomes in a cohort of patients with systemic lupus erythematosus

OBJECTIVES

Antiphospholipid syndrome (APS) is characterised by the presence of antiphospholipid antibodies (aPLs) and clinical outcomes of thrombosis and/or obstetric morbidity and is associated with systemic lupus erythematosus (SLE). IgG antiphosphatidylserine/prothrombin complex (aPS/PT), IgM aPS/PT and IgG anti-beta 2 glycoprotein 1-domain 1 (aβ2GP1-D1) are novel aPLs that have been associated with thrombosis; however, conclusive data are still lacking. It remains unclear how best to incorporate non-criteria autoantibodies into clinical decision-making. The aim of this study was to assess whether these novel aPLs were associated with an increased risk of thrombosis in patients with SLE.

METHODS

We evaluated 341 patients enrolled in the SouThern Alberta Registry for Lupus EryThematosus database with SLE by the American College of Rheumatology or Systemic Lupus International Collaborating Clinics classification criteria. Medical records were reviewed between March 2006 and January 2021 for thrombotic events and serology results for lupus anticoagulant, IgG anticardiolipin, IgG anti-beta 2 glycoprotein 1 (aβ2GP1), IgG aPS/PT, IgM aPS/PT and IgG aβ2GP1-D1.

RESULTS

Among 341 patients with SLE, 59 (17%) met the revised Sapporo lab criteria, and of those 29 (49%) had a major thrombotic event (OR 3.5, 95% CI 1.9 to 6.3). Among 142 patients who had at least one positive non-criteria autoantibody, 45 (32%) had a major thrombotic event (OR 1.6, 95% CI 0.97 to 2.6). In a univariate analysis, the IgG aPS/PT and IgG aβ2GP1-D1 were associated with major and all thrombotic events. In a multivariate analysis that controlled for age, sex, prednisone use, SLE disease activity (Systemic Lupus Erythematosus Disease Activity Index-2K and the revised Sapporo lab criteria, among the non-criteria aPLs, only IgG aPS/PT was associated with an increased risk of a major thrombosis (OR 2.2, 95% CI 1.1 to 4.5).

CONCLUSIONS

In our multivariate analysis, IgG aPS/PT was associated with a modestly increased risk of thrombotic events.

Obesity: Friend or Foe in Sjögren's Syndrome Patients?

BACKGROUND/OBJECTIVES

In Sjögren's syndrome, exocrine glands are destructed in an autoimmune-mediated process. Obesity is known to influence a wide range of diseases. This study aimed to examine whether obesity has an impact on the disease course of our patients with Sjögren's syndrome.

METHODS

Out of the regularly followed-up patients, 125 were grouped based on their body mass index (BMI). Below a BMI of 25, they were listed as "non-obese" (n = 45), whereas above a BMI of 25, they were categorized as "obese" (n = 80). Demographic, laboratory, and immunological parameters; Sjögren's syndrome disease activity index; certain extraglandular manifestations; and treatment modalities were compared using biostatistical methods.

RESULTS

Among the examined cardiovascular and cerebrovascular co-morbidities, type 2 diabetes and hypertension were significantly more frequent in the obese group. Considering the associated further autoimmune disorders and extraglandular manifestations, in our patients, there were no significant differences between the two groups. Among laboratory parameters, gamma glutamil transferase, alanine transaminase, hemoglobin, hematocrit, lymphocyte rate, triglyceride, and c3 and c4 complement levels were significantly higher in the obese group, while the proportion of rheumatoid factor positivity and the neutrophil granulocyte rate were significantly lower. Immunoglobulin G, A, and M levels did not differ significantly between the two subsets. Obese patients needed steroid therapy significantly less frequently; however, statin therapy was remarkably more frequent in that group. Furthermore, the European League Against Rheumatism (EULAR) Sjögren's syndrome disease activity index (ESSDAI) was significantly lower in the group of overweight patients.

CONCLUSIONS

Our results suggest that several immunological parameters of obese patients are more favorable compared to those with normal body weight. Behind that, we might suspect either the beneficial effect of statin therapy and/or the obesity paradox.

Branch Retinal Artery Occlusion as a Presentation of Seronegative Antiphospholipid Syndrome in Pregnancy

A 40-year-old gravida 7 para 4+2 lady who was 14 weeks pregnant presented with a three-day history of sudden-onset flashes of light associated with a superonasal visual field defect on her right eye. She had two prior miscarriages that occurred in the second and third trimesters. Previous serological tests for antiphospholipid syndrome (APS) were normal. No other comorbidities were reported. On examination, visual acuity for both eyes was 6/6 with normal intra-ocular pressure. There was an embolus lodged at the inferotemporal peripheral retinal artery of the right eye with adjacent pale and oedematous distal retina. This corresponded with a superonasal scotoma on the Humphrey 30-2 visual field test. Other examinations were unremarkable. The patient was referred to obstetrics, rheumatology, and neuro-medical teams for co-management. Full blood count, coagulation profile, auto-immune panel, and antiphospholipid serological screening test were normal. No abnormalities were seen on her electrocardiogram and echocardiogram. A magnetic resonance angiogram of the brain revealed significant bilateral internal carotid stenosis at C2 and C6 levels. However carotid artery assessment showed normal flow below the jawline. The patient was diagnosed with seronegative APS with right-eye inferotemporal branch retinal artery occlusion (BRAO). A multidisciplinary team monitored her pregnancy, and she was started on subcutaneous enoxaparin 40 mg twice a day and oral aspirin/glycine 100 mg/45 mg once daily. At 20 weeks of pregnancy, the Hollenhorst plaque disappeared, and the visual field defect started to improve. She went on to deliver a healthy child at 36+6 weeks. Post-partum, she has continued on oral aspirin 100 mg once daily. A carotid angiogram performed post-delivery showed no evidence of internal carotid artery stenosis or thrombosis. This case highlights the importance of recognizing BRAO as it can be the presentation of a previously unrecognized seronegative antiphospholipid syndrome. Early recognition of the correct diagnosis is vital to allow effective multidisciplinary management, especially when dealing with a patient in pregnancy.

Efficacy of the Hepcon system in reducing hemorrhagic and thrombotic complications in antiphospholipid syndrome patients undergoing cardiac surgery

INTRODUCTION

Patients with Antiphospholipid Syndrome (APS) undergoing cardiopulmonary bypass (CPB) surgery are at increased risk for thrombotic and hemorrhagic complications. Anticoagulation during CPB is typically monitored with activated clotting time (ACT) which may be falsely prolonged in patients with APS. The Hepcon Hemostasis Management System quantitatively determines the whole blood heparin concentration through heparin/protamine titration.

METHODS

This was a retrospective study of APS patients who underwent cardiac surgery requiring CPB at the Cleveland Clinic between April 2013, and July 2020. The primary endpoint was the composite rate of hemorrhagic or thromboembolic complications per surgical case in patients monitored by Hepcon versus patients monitored by ACT. Secondary endpoints were median volume of chest tube output and packed red blood cell (PRBC) transfusion within the first three post-operative days.

RESULTS

43 patients were included. 20 (47%) patients were monitored using Hepcon while 23 (53%) were monitored using ACT. For the primary endpoint of rate of thromboembolic or hemorrhagic complications per surgical case, there was no statistically significant difference between the Hepcon and ACT groups (HMS, 6/20 [30%]; ACT, 7/23 [30%]; p = >0.99). For the secondary endpoints, there was no statistically significant difference in median post-operative chest tube output (780 mL vs. 850 mL; p = 0.88) and median post-operative PRBC transfusion (1 unit vs. 0 unit; p = 0.28) between the Hepcon and ACT groups, respectively.

CONCLUSION

There was no difference in the composite outcome of thrombotic or hemorrhagic complications in patients monitored by Hepcon versus those monitored by ACT.

Antiphospholipid Syndrome and Catastrophic Antiphospholipid Syndrome: A Comprehensive Review of Pathogenesis, Clinical Features, and Management Strategies

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the presence of antiphospholipid antibodies (aPLs) that predispose individuals to thrombotic events and pregnancy-related complications. APS can occur as a primary condition or in association with other autoimmune diseases, most commonly systemic lupus erythematosus (SLE). Catastrophic APS (CAPS) is a rare, severe variant of APS, marked by rapid-onset, widespread thrombosis leading to multi-organ failure, often triggered by infections, surgical procedures, or cessation of anticoagulation therapy. Both APS and CAPS present significant clinical challenges due to their potential for severe morbidity and mortality. This comprehensive review aims to provide a detailed overview of the pathogenesis, clinical features, diagnostic criteria, and management strategies for APS and CAPS. The review highlights the immunological mechanisms underlying APS, including the role of aPLs, complement system activation, and endothelial cell dysfunction in developing thrombosis. It also outlines the clinical manifestations of APS, such as venous and arterial thrombosis, pregnancy morbidity, and neurological symptoms, along with the diagnostic criteria based on clinical and laboratory findings. The review delves into its pathogenesis, clinical presentation, and diagnostic challenges in the context of CAPS, emphasizing the need for immediate and intensive therapy to manage this life-threatening condition. Current management strategies for APS, including anticoagulant therapy, immunomodulatory treatments, and specific interventions for pregnancy-related complications, are discussed. The review highlights the importance of a multidisciplinary approach for CAPS, combining anticoagulation, high-dose corticosteroids, plasma exchange, and intravenous immunoglobulin. The review also addresses the prognosis and long-term outcomes for patients with APS and CAPS, underlining the necessity for ongoing monitoring and follow-up to prevent recurrent thrombotic events and manage chronic complications. Finally, future directions in research are explored, focusing on emerging therapies, biomarkers for early diagnosis, and the need for clinical trials to advance the understanding and treatment of these complex syndromes. By enhancing the understanding of APS and CAPS, this review aims to improve diagnosis, treatment, and patient care, ultimately leading to better health outcomes for those affected by these conditions.

Antiphospholipid Syndrome: Insights into Molecular Mechanisms and Clinical Manifestations

Antiphospholipid syndrome (APS) is a complex systemic autoimmune disorder characterized by a hypercoagulable state, leading to severe vascular thrombosis and obstetric complications. The 2023 ACR/EULAR guidelines have revolutionized the classification and understanding of APS, introducing broader diagnostic criteria that encompass previously overlooked cardiac, renal, and hematologic manifestations. Despite these advancements, diagnosing APS remains particularly challenging in seronegative patients, where traditional tests fail, yet clinical symptoms persist. Emerging non-criteria antiphospholipid antibodies offer promising new diagnostic and management avenues for these patients. Managing APS involves a strategic balance of cardiovascular risk mitigation and long-term anticoagulation therapy, though the use of direct oral anticoagulants remains contentious due to varying efficacy and safety profiles. This article delves into the intricate pathogenesis of APS, explores the latest classification criteria, and evaluates cutting-edge diagnostic tools and therapeutic strategies.

Interaction of antiphospholipid antibodies with endothelial cells in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease with arteriovenous thrombosis and recurrent miscarriages as the main clinical manifestations. Due to the complexity of its mechanisms and the diversity of its manifestations, its diagnosis and treatment remain challenging issues. Antiphospholipid antibodies (aPL) not only serve as crucial "biomarkers" in diagnosing APS but also act as the "culprits" of the disease. Endothelial cells (ECs), as one of the core target cells of aPL, bridge the gap between the molecular level of these antibodies and the tissue and organ level of pathological changes. A more in-depth exploration of the relationship between ECs and the pathogenesis of APS holds the potential for significant advancements in the precise diagnosis, classification, and therapy of APS. Many researchers have highlighted the vital involvement of ECs in APS and the underlying mechanisms governing their functionality. Through extensive in vitro and in vivo experiments, they have identified multiple aPL receptors on the EC membrane and various intracellular pathways. This article furnishes a comprehensive overview and summary of these receptors and signaling pathways, offering prospective targets for APS therapy.

Risk factors for thrombotic events in systemic lupus erythematosus patients with antiphospholipid antibodies: insights from morphometric measurements of carotid arteries

Objective

To identify the correlation between thrombosis and atherosclerosis in systemic lupus erythematosus (SLE) patients with antiphospholipid antibodies (aPLs) (SLE/aPLs) through high-resolution magnetic resonance imaging (HR-MRI) of the carotid artery.

Methods

A single-center, cross-sectional study was conducted. We collected consecutive patients with SLE/aPLs and healthy controls who underwent carotid HR-MRI examinations. The morphometric characteristics of the common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA), and carotid bulb (Sinus) were measured, and the differences in morphometric parameters between different groups were analyzed.

Results

A total of 144 carotid arteries were analyzed. Compared with the control group, the wall area, wall thickness (WT and WTmax), and normalized wall index of CCA, ICA, ECA, and Sinus were increased in patients with SLE/aPLs, and the total vascular area (TVA) of CCA, ICA, and Sinus, and the bifurcation angle (BIFA) of ICA-ECA were also increased. A negative lupus anticoagulant (LAC) (with or without positive anticardiolipin antibody (aCL) or anti-β2glycoprotein antibody (aβ2GPI)) contributed to illustrating lower increased TVA and thickened vessel walls of CCA and ICA in SLE/aPLs patients without thrombotic events. Logistic regression analysis showed that WTmaxSinus and WTmaxGlobal were independent risk factors for thrombotic events in SLE/aPLs patients. The receiver operator characteristic curve showed that the cut-off value of WTmaxSinus was 2.855 mm, and WTmaxGlobal was 3.370 mm.

Conclusion

HR-MRI ensures the complete and accurate measurement of carotid morphometric parameters. Compared with the control group, the carotid artery in patients with SLE/aPLs is mainly characterized by diffusely thickened vessel walls, and the patients with thrombotic events showed additional higher vascular area of CCA and ICA, and BIFA of ICA-ECA without significant change in lumen area. The carotid arteries of SLE/aPLs patients with thrombotic events exhibited significant vessel wall thickening in all segments except ECA compared to those without thrombotic events. LAC-negative and non-thrombotic events distinguish relatively early atherosclerosis in the carotid arteries in patients with SLE/aPLs. Patients with SLE/aPLs that possess circumscribed thickened carotid vessel walls (>3.370 mm), particularly thickened at the Sinus (>2.855 mm), may require management strategies for the risk of thrombotic events.

Antiphospholipid antibodies in patients with antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a rare systemic autoimmune disease characterized by recurrent pregnancy morbidity or thrombosis in combination with the persistent presence of antiphospholipid antibodies (aPLs) in plasma/serum. Antiphospholipid antibodies are a heterogeneous, overlapping group of autoantibodies, of which anti-β2-glycoprotein I (aβ2GPI), anticardiolipin (aCL) antibodies and antibodies that prolong plasma clotting time in tests in vitro known as lupus anticoagulant (LAC) are included in the laboratory criteria for the diagnosis of APS. The presence of LAC antibodies in plasma is indirectly determined by measuring the length of coagulation in two tests - activated partial thromboplastin time (aPTT) and diluted Russell's viper venom time (dRVVT). The concentration of aβ2GPI and aCL (immunglobulin G (IgG) and immunoglobulin M (IgM) isotypes) in serum is directly determined by solid-phase immunoassays, either by enzyme-linked immunosorbent assay (ELISA), fluoroimmunoassay (FIA), immunochemiluminescence (CLIA) or multiplex flow immunoassay (MFIA). For patient safety, it is extremely important to control all three phases of laboratory testing, i.e. preanalytical, analytical and postanalytical phase. Specialists in laboratory medicine must be aware of interferences in all three phases of laboratory testing, in order to minimize these interferences. The aim of this review was to show the current pathophysiological aspects of APS, the importance of determining aPLs-a in plasma/serum, with an emphasis on possible interferences that should be taken into account when interpreting laboratory findings.

Taipan snake venom time has high sensitivity for lupus anticoagulants in non-anticoagulated, triple positive antiphospholipid syndrome patients

INTRODUCTION

Dilute Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT) are the mainstay assays in lupus anticoagulant (LA) detection yet they have limitations, particularly in relation to interferences and specificity. The recently validated Taipan snake venom time (TSVT) screening with ecarin time (ET) confirmatory assays overcome many of those limitations due to the innate specificity engendered from direct prothrombin activation, and insensitivity to the effects of vitamin K antagonists (VKA). The present study aimed to further evidence diagnostic utility of TSVT/ET by performing them in samples from 116 nonanticoagulated patients with established triple-positive antiphospholipid syndrome (APS).

METHODS

Samples were identified in three expert centres who performed dRVVT, APTT and solid phase antiphospholipid antibody assays with reagents from a variety of manufacturers. All samples additionally received TSVT/ET analysis using standardised reagents.

RESULTS

Ninety seven of 116 (83.6%) were dRVVT- and APTT-positive, 85/97 (87.6%) of which were TSVT/ET-positive, 9/116 (7.8%) were dRVVT-positive only, 6 of which were TSVT/ET-positive, and 10/116 (8.6%) were APTT-positive only, 5 of which were TSVT/ET-positive. 96/116 TSVT/ET-positivity returned a high sensitivity for LA of 82.8%. Low coefficients of determination revealed weak relationships between LA potency and anticardiolipin and anti-β2-glycoprotein I antibody titres for all three LA assays.

CONCLUSIONS

TSVT/ET has high sensitivity for the clinically significant LA found in triple positive APS patients. TSVT/ET can establish multiple LA assay positivity in nonanticoagulated patients negative for one of dRVVT or APTT, and is the only assay pairing insensitive to VKAs, the recommended anticoagulation for APS.

D-dimer and fibrinogen indicate ischemic risk in patients with atrial fibrillation after percutaneous coronary intervention

BACKGROUND

This study aimed to evaluate the association of antiphospholipid antibodies (aPL) and conventional markers of coagulation with ischemic and bleeding risk in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI).

METHODS

In this prospective two-center observational cohort study, patients with AF and an indication for oral anticoagulation (OAC) were enrolled after PCI. Blood was drawn on day 1-3 after PCI. Dilute Russell's viper venom time was used to determine lupus anticoagulant (LA) in OAC-free plasma. Anti-cardiolipin (aCL) IgG, IgM, and anti-β2-Glycoprotein 1 (aβ2GP1) IgG were analyzed by enzyme-linked immunosorbent assay (ELISA). Fibrinogen (FIB), d-dimer, and prothrombin fragment 1 and 2 (PF 1 + 2) were measured in citrated plasma. The primary ischemic outcome was time to major adverse cardiovascular events (MACE; death, myocardial infarction, or stroke) assessed at 6 months. Bleeding was defined according to International Society on Thrombosis and Haemostasis.

RESULTS

158 patients were enrolled between May 2020 and May 2021 on day 1-3 after PCI. The median age was 78 years (interquartile range [IQR] 72-82), 111 (70%) were male, and 39 (25%) presented with acute coronary syndrome. D-dimer was elevated in 74 (47%) patients, FIB was increased in 40 (25%) and PF1 + 2 in 68 (43%) patients. 32 (20%) patients had ≥ 1 antiphospholipid antibody elevated (aPL; LA: 19 [12%], aCL: 14 [9%], aβ2GP1: 2 [1%]). The presence of aPL was neither significantly associated with MACE (HR 1.46, 95% CI [0.39-5.49], p = 0.579), nor bleeding (HR 1.07 [0.30-3.84], p = 0.917). Elevated d-dimer was significantly associated with higher risk for MACE (HR 5.06 [1.09-23.41], p = 0.038) and major bleeding (HR 7.04 [1.58-31.47], p = 0.011). Elevated D-dimer increased the predictive capacity of HAS-BLED for major bleedings (HAS-BLED: AUC 0.71 [0.60-0.83] vs. HAS-BLED + d-dimer: AUC 0.79 [0.70-0.88]; p = 0.025). Increased levels of FIB were associated with higher risk for MACE (HR 3.65 [1.11-11.96], p = 0.033).

CONCLUSION

Biomarkers of coagulation might be suitable to assess ischemic and bleeding risk in patients with AF following PCI.

[Obstetric Antiphospholipid Syndrome: Insights on the Diagnosis, Treatment, and Hot Issues]

Obstetric antiphospholipid syndrome (OAPS) is an autoimmune disorder associated with various pathological pregnancies, such as recurrent miscarriage, stillbirth, severe pre-eclampsia and severe placental insufficiency. The persistent presence of antiphospholipid antibodies (aPLs) is the most important laboratory characteristic of OAPS. OAPS severely affects the reproductive health of women of childbearing age in China. Reports indicate that approximately 9.6% stillbirths, 11.5% severe pre-eclampsia, and 54% recurrent miscarriages are associated with OAPS or aPLs. However, the pathogenesis of OAPS remains unclear. Previously, thrombosis at the maternal-fetal interface (MFI) was considered the main mechanism of OAPS-related pathological pregnancies. Consequently, the use of low molecular weight heparin and aspirin throughout pregnancy was recommended to improve outcomes in OAPS patient. In recent years, many studies have found that thrombosis in MFI is uncommon, but various inflammatory factors are significantly increased in the MFI of OAPS patients. Based on these findings, some clinicians have started using anti-inflammatory treatments for OAPS, which have preliminarily improved the pregnancy outcomes. Nevertheless, there is no consensus on these second-line treatments of OAPS. Another troubling issue is the clinical diagnosis of OAPS. Similar to other autoimmune diseases, there are only classification criteria for OAPS, and clinical diagnosis of OAPS depends on the clinicians' experience. The present classification criteria of OAPS were established for clinical and basic research purposes, not for patient clinical management. In clinical practice, many patients with both positive aPLs and pathological pregnancy histories do not meet the strict OAPS criteria. This has led to widespread issues of incorrect diagnosis and treatment. Timely and accurate diagnosis of OAPS is crucial for effective treatment. In this article, we reviewed the epidemiological research progress on OAPS and summarized its classification principles, including: 1) the persistent presence of aPLs in circulation; 2) manifestations of OAPS, excluding other possible causes. For the first point, accurate assessment of aPLs is crucial; for the latter, previous studies regarded only placenta-related pregnancy complications as characteristic manifestations of OAPS. However, recent studies have indicated that adverse pregnancy outcomes related to trophoblast damage, such as recurrent miscarriage and stillbirth, also need to be considered in OAPS. We also discussed several key issues in the diagnosis and treatment of OAPS. First, we addressed the definition of non-standard OAPS and offered our opinion on defining non-standard OAPS within the framework of the 2023 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) APS criteria. Then, we discussed the advantages and disadvantages of different aPL testing methods, emphasizing that harmonizing results across platforms and establishing specific reference values are keys to resolving controversies in aPL testing results. We also introduced the application of non-criteria aPLs, especially anti-phosphatidylserine/prothrombin antibody (aPS/PT) and anti-β2 glycoprotein Ⅰ domain Ⅰ antibody (aβ2GPⅠDⅠ). Additionally, we discussed aPL-based OAPS risk classification strategies. Finally, we proposed potential treatment methods for refractory OAPS. The goal is to provide a reference for the clinical management of OAPS.

Cryo-EM structure and functional basis of prothrombin recognition by a type I antiprothrombin antiphospholipid antibody

ABSTRACT

Antiprothrombin antibodies are found in antiphospholipid patients, but how they interact with prothrombin remains elusive. Prothrombin adopts closed and open forms. We recently discovered type I and type II antibodies and proposed that type I recognizes the open form. In this study, we report the discovery and structural and functional characterization in human plasma of a type I antibody, POmAb (prothrombin open monoclonal antibody). Using surface plasmon resonance and single-molecule spectroscopy, we show that POmAb interacts with kringle-1 of prothrombin, shifting the equilibrium toward the open form. Using single-particle cryogenic electron microscopy (cryo-EM), we establish that the epitope targeted by POmAb is in kringle-1, comprising an extended binding interface centered at residues R90-Y93. The 3.2-Å cryo-EM structure of the complex reveals that the epitope overlaps with the position occupied by the protease domain of prothrombin in the closed state, explaining the exclusive binding of POmAb to the open form. In human plasma, POmAb prolongs phospholipid-initiated and diluted Russell's viper venom clotting time, which could be partly rescued by excess phospholipids, indicating POmAb is an anticoagulant but exerts a weak lupus anticoagulant effect. These studies reveal the structural basis of prothrombin recognition by a type I antiphospholipid antibody and uncover an exciting new strategy to achieve anticoagulation in human plasma.

Bibliometric analysis of the global trends in immune-related recurrent pregnancy loss research over the last two decades

PROBLEM

A comprehensive analysis was conducted to explore the scientific output on immune-related recurrent pregnancy loss (RPL) and its key aspects. Despite the lack of clear explanations for most RPL cases, immune factors were found to play a significant role.

METHOD OF STUDY

The study utilized a bibliometric approach, searching the Web of Science Core Collection database for relevant literature published between 2004 and 2023.

RESULTS

The collected dataset consisted of 2228 articles and reviews, revealing a consistent increase in publications and citations over the past two decades. The analysis identified the United States and China as the most productive countries in terms of RPL research. Among the institutions, Fudan University in China emerged as the top contributor, followed by Shanghai Jiaotong University. Kwak-kim J was the most prolific author, while Christiansen Ob had the highest number of co-citations. The top 25 co-cited references on diagnosis, treatment, and mechanisms formed the foundation of knowledge in this field. By examining keyword co-occurrence and co-citations, the study found that antiphospholipid syndrome and natural killer cells were the primary areas of focus in immune-related RPL research. Additionally, three emerging hotspots were identified: chronic endometritis, inflammation, and decidual macrophages. These aspects demonstrated increasing interest and research activity within the field of immune-related RPL.

CONCLUSIONS

Overall, this comprehensive bibliometric analysis provided valuable insights into the patterns, frontiers, and focal points of global scientific output related to immune-related RPL.

How We Interpret Thrombosis with Thrombocytopenia Syndrome?

Platelets play an important role in hemostasis, and a low platelet count usually increases the risk of bleeding. Conditions in which thrombosis occurs despite low platelet counts are referred to as thrombosis with thrombocytopenia syndrome, including heparin-induced thrombocytopenia, vaccine-induced immune thrombotic thrombocytopenia, paroxysmal nocturnal hemoglobinuria, antiphospholipid syndrome, thrombotic microangiopathy (TMA), and disseminated intravascular coagulation. TMA includes thrombotic thrombocytopenic purpura, Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (HUS), and atypical HUS. Patients with these pathologies present with thrombosis and consumptive thrombocytopenia associated with the activation of platelets and the coagulation system. Treatment varies from disease to disease, and many diseases have direct impacts on mortality and organ prognosis if therapeutic interventions are not promptly implemented. Underlying diseases and the results of physical examinations and general laboratory tests as part of a thorough workup for patients should promptly lead to therapeutic intervention before definitive diagnosis. For some diseases, the diagnosis and initial treatment must proceed in parallel. Utilization of not only laboratory tests but also various scoring systems is important for validating therapeutic interventions based on clinical information.

Low recurrent thrombosis rates in single positive antiphospholipid syndrome regardless of type of anticoagulation

Thrombotic antiphospholipid syndrome (TAPS) is characterized by thrombosis and persistently positive tests for antiphospholipid antibodies or lupus anticoagulant (LAC). Triple-positive APS has the highest risk of recurrent thrombosis, but no studies have focused on recurrent thrombosis in patients with single-positive TAPS. We conducted a retrospective cohort study of patients with single-positive TAPS diagnosed at Lifespan Health System, Rhode Island, to determine the rates and risk factors for recurrent thrombosis. Between January 2001 and April 2022, 128 patients were assessed who had single-positive APS (LAC = 98, aCL = 21, aβ2GPI = 9) and who had been followed for a total of 1453.8 patient-years (median follow-up 3.04 years). The initial antithrombotic regimen was warfarin in 44 %, a direct oral anticoagulant (DOAC) in 34 %, enoxaparin in 2 %, and no antithrombotic therapy or antiplatelet therapy only in 20 %. Recurrent thrombosis occurred in 16 (12.5 %) with a recurrent thrombosis rate of 3.08 per 100 patient-years. Systemic lupus erythematosus was the only variable significantly associated with recurrent thrombosis in a model adjusted for age, sex, body mass index, and type of positive APS test. All 16 patients with recurrent thrombosis were initially treated with warfarin, and, at the time of recurrent thrombosis, 13 patients remained on warfarin and three were off anticoagulation. In conclusion, the recurrent thrombosis rate in single-positive APS is low, and not all patients with a single-positive test may need indefinite anticoagulation with warfarin. Larger prospective studies are required to confirm this finding and establish optimal anticoagulation regimens for low-risk TAPS.

Prolongated Activated Partial Thromboplastin Time (aPTT) in Pediatric Patients before Surgery-Crying Wolf: Lupus (Anticoagulant) Does Not Always Threaten Children

A prolonged preoperatory aPTT in children is often the cause of a delay of scheduled surgeries and the repetition of multiple blood tests, with the consequent wasting of resources and significant discomfort for children and parents. The aim of this review is to analyze the situations in which an isolated prolongation of aPTT is found during preoperative evaluation in children, especially when it is due to the presence of antiphospholipid antibodies, providing the readers with the keys to interpret this situation and the possibility to correctly evaluate the hemorrhagic risk of a patient.

A Rare Case of Postpartum Paraplegia: A Case Report

In this case report, a 27-year-old woman who had pre-eclampsia in the past and had a cesarean section as a result of the condition presents with an uncommon and difficult form of postpartum paraplegia. She experienced bilateral lower limb paralysis and urine incontinence soon after the surgery, which quickly led to unconsciousness and required mechanical ventilator support and intensive care treatment. Comprehensive diagnostic testing, which included magnetic resonance imaging scans of the brain and spinal cord, identified signs typical of "Posterior Reversible Encephalopathy Syndrome (PRES)" and spinal cord infarction affecting segments C3 to D2. "Antiphospholipid Antibody Syndrome (APLA)" was identified by laboratory testing, highlighting the significance of taking a thorough approach to comprehending this uncommon clinical condition. Treatment included anticoagulant therapy, high-dose steroid therapy, and antihypertensive drugs, emphasizing the crucial importance of inter-disciplinary care in handling such complex situations. Even if the patient's symptoms have partially improved, their condition is still being closely monitored in the intensive care unit. In the context of postpartum neurological problems and the complex interplay between pre-eclampsia, spinal cord infarction, and related clinical symptoms, this case emphasizes the need for increased awareness and prompt management.

A Rare Case of Antiphospholipid Syndrome With Concomitant Antithrombin III Deficiency: A Case Report

Antithrombin (AT) deficiency and antiphospholipid syndrome (APS) are distinct but potentially overlapping disorders with significant implications for thrombosis. We present a case of a 28-year-old male with hereditary AT deficiency who subsequently developed primary APS. Despite the challenges of overlapping symptoms and anticoagulation therapy, a careful diagnostic approach revealed the coexistence of these rare conditions. The patient was successfully managed with long-term anticoagulation, hydroxychloroquine, and other supportive measures. This case underscores the importance of comprehensive laboratory testing, especially when managing patients with pre-existing anticoagulation needs.

Key Issues at the Forefront of Diagnosis and Testing for Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by antiphospholipid antibodies associated with thrombosis and pregnancy complications. Catastrophic APS is a severe form involving multiple organ systems with a high mortality rate. The pathogenesis involves antiphospholipid antibodies which target phospholipid-binding proteins and damage endothelial cells thus activating coagulation, triggering a pro-thrombotic state. Laboratory tests for antiphospholipid antibody detection include lupus anticoagulant testing in the coagulation laboratory and serological detection of anticardiolipin and anti-beta 2 glycoprotein I antibodies. Despite recent updates in the diagnostic criteria for APS the recent decades and our improved knowledge of this disease, there remain several key issues pertaining to diagnosis and testing with potential implications to patient management. Here we briefly review APS pathophysiology, strengths and weaknesses of classification criteria, laboratory challenges leading to test interpretation, and clinical management of this complex condition.

Determining Thrombogenicity: Using a Modified Thrombin Generation Assay to Detect the Level of Thrombotic Event Risk in Lupus Anticoagulant-Positive Patients

The aim of this study was to determine the thrombogenicity of lupus anticoagulant (LA) antibodies using a modified thrombin generation assay (TGA) with the addition of activated protein C (APC) in a group of 85 patients with LA-positive samples. Of these, 58 patients had clinical manifestations of antiphospholipid syndrome (APS) according to the Sydney criteria classification, i.e., each patient had thrombosis or foetal loss, and 27 patients did not show any clinical manifestations of APS. A comparison of the two groups' TGA results revealed statistically significant differences (Fisher's test p = 0.0016). The group of patients exhibiting clinical manifestations of APS showed higher thrombogenicity in 56.9% of patients, while the group of patients not yet exhibiting clinical manifestations of APS showed higher thrombogenicity in 25.9% of patients. There were no significant differences in the specificity of the TGA test between the groups of patients exhibiting similar clinical manifestations. Receiver operating characteristic curve analysis showed a more significant relationship (p = 0.0060) for TGA than for LA titre (p = 0.3387). These data suggest that the determination of LA thrombogenicity with the TGA assay leads to an increased prediction of the manifestation of a thromboembolic event. Our findings appear to be particularly relevant for the prediction of thrombotic events in patients with laboratory-expressed APS and no clinical manifestations.

A rare concurrent incidence of adult-onset acute disseminated encephalomyelitis and antiphospholipid antibody syndrome: A case report

INTRODUCTION

Acute disseminated encephalomyelitis (ADEM) is a demyelinating immune-mediated condition of the central nervous system, whereas antiphospholipid antibody syndrome (APLA) is an autoimmune disorder accompanied by thrombosis and pregnancy-related problems. We present a unique case of a 30-year-old female with ADEM coexisting with APLA, highlighting the importance of early identification and specialized care.

PRESENTATION OF CASE

We present a case of a 30-year-old woman with a history of hypertension, multiple miscarriages, and non-compliance with medication, who presented with altered consciousness and weakness in all four limbs. Laboratory tests revealed positive anti-cardiolipin and lupus anticoagulant antibodies, confirming APLA. A neurological examination revealed increased limb tone, heightened reflexes, and extensor plantar responses. MRI revealed confluent white matter lesions that were consistent with ADEM. The patient received prompt treatment with intravenous methylprednisolone and then received oral prednisone, leading to a rapid improvement in neurological status.

DISCUSSION

The intricate interaction between ADEM and APLA remains enigmatic. The plausible connection between "molecular mimicry" and weakened blood-brain barrier, substantiated by antiphospholipid antibodies, may help explain their concurrent occurrence.

CONCLUSION

This case highlights the significance of early diagnosis and management of the rare and complex coexistence of ADEM and APLA to attain optimal outcomes, as well as the significance of careful examination for simultaneous autoimmune markers in individuals presenting with neurological disturbances.

Triple-positive antiphospholipid syndrome does not guarantee positivity in each lupus anticoagulant assay

BACKGROUND

Triple positivity for all 3 criteria antiphospholipid antibodies confers high risk of symptom development in carriers, and recurrence in antiphospholipid syndrome (APS). Most triple-positivity studies report lupus anticoagulant (LA) testing as positive without distinguishing between positivity with dilute Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT) and single-assay positivity or only perform dRVVT. Single LA assay repertoires remain in use in some centers, which risks missing some triple positives. Positivity with both assays may identify higher risk.

OBJECTIVES

The aim of this study is to investigate the frequency of single LA assay positivity in triple-positive patients.

METHODS

Three hundred forty-two triple-positive profiles from nonanticoagulated patients (237 APS, 45 systemic lupus erythematosus without APS symptoms, and 60 nonclinical criteria) were identified from laboratory databases and assessed for LA positivity by dRVVT and/or APTT.

RESULTS

Seventy-three of 237 (30.8%) APS samples were LA-positive with 1 assay, 40/237 (16.9%) by dRVVT only, and 33/237 (13.9%) with APTT only. Nineteen of 45 (42.2%) were LA-positive with 1 assay in the systemic lupus erythematosus cohort; 12/45 (26.7%) with dRVVT only and 7/45 (15.5%) with APTT only. Thirty-three of 60 (55.0%) were LA-positive with 1 assay in the nonclinical criteria cohort; 24/60 (40.0%) with dRVVT only and 9/60 (15.0%) with APTT only. The most common solid-phase assay profile was elevated immunoglobulin G aCL and aβ2GPI.

CONCLUSION

Up to 55.0% of triple-positive samples were positive in 1 LA assay, representing significant potential for misdiagnosis and inappropriate management via single LA assay repertoires.

Anti-phospholipid autoantibodies in human diseases

Anti-phospholipid autoantibodies are a group of antibodies that can specifically bind to anionic phospholipids and phospholipid protein complexes. Recent studies have reported elevated serum anti-phospholipid autoantibody levels in patients with antiphospholipid syndrome, systemic lupus erythematosus, rheumatoid arthritis, metabolic disorders, malaria, SARS-CoV-2 infection, obstetric diseases and cardiovascular diseases. However, the underlying mechanisms of anti-phospholipid autoantibodies in disease pathogenesis remain largely unclear. Emerging evidence indicate that anti-phospholipid autoantibodies modulate NETs formation, monocyte activation, blockade of apoptotic cell phagocytosis in macrophages, complement activation, dendritic cell activation and vascular endothelial cell activation. Herein, we provide an update on recent advances in elucidating the effector mechanisms of anti-phospholipid autoantibodies in the pathogenesis of various diseases, which may facilitate the development of potential therapeutic targets for the treatment of anti-phospholipid autoantibody-related disorders.

Endothelial Progenitor Cells in Autoimmune Disorders

Circulating endothelial progenitor cells (EPCs) were first described in 1997 by Asahara et al. as "putative endothelial cells" from human peripheral blood. The study of endothelial progenitors is also intensifying in several pathologies associated with endothelial damage, including diabetes, myocardial infarction, sepsis, pulmonary arterial hypertension, obstructive bronchopneumopathy and transplantation. EPCs have been studied in several autoimmune diseases with endothelial involvement such as systemic lupus erythematosus, thrombotic thrombocytopenic purpura, antineutrophil cytoplasmic antibodies, vasculitis, rheumatoid arthritis, Goujerot-Sjögren and antiphospholipid syndrome. Factors involved in endothelial damage are due to overexpression of pro-inflammatory cytokines and/or autoantibodies. Management of these pathologies, particularly the long-term use of glucocorticoids and methotrexate, promote atherosclerosis. A lack of standardized assessment of the number and function of EPCs represents a serious challenge for the use of EPCs as prognostic markers of cardiovascular diseases (CVD). The objective of this review was to describe EPCs, their properties and their involvement in several autoimmune diseases.

SAMD1 attenuates antiphospholipid syndrome-induced pregnancy complications

OBJECTIVE

This study was intended to investigate the effect of SAMD1 on antiphospholipid syndrome (APS)-induced pregnancy complications in mice.

METHODS

The mRNA and protein expression of SAMD1 in APS patients and healthy controls was detected by qRT-PCR and western blot. Anti-B2 GPI and ACA levels were tested by ELISA, MMP-9, iNOS, ICAM-1 and MCP-1 mRNA and protein levels determined by qRT-PCR and western blot, cellular senescence detected by β-galactosidase staining, cell proliferation ability detected by CCK-8 assay, cell viability detected by trypan blue staining, cell mobility detected by Transwell, and cell angiogenesis ability detected by matrigel tube formation assay. An APS pregnant mouse model was constructed, and the embryo absorption rate was calculated.

RESULTS

SAMD1 expression was low in serum of APS patients, which was correlated with the history of thrombosis and the number of adverse pregnancies. Anti-B2 GPI and ACA levels were increased in APS. The expressions of MMP-9, iNOS, ICAM-1, and MCP-1 were also significantly upregulated in HUVECs treated with APS serum. APS promoted HUVEC senescence and inhibited cell proliferation, migration and angiogenesis. Overexpression of SAMD1 reversed the above results. Experiments on the APS pregnant mouse model confirmed that overexpression of SAMD1 reduced the rate of fetal loss.

CONCLUSION

SAMD1 may reduce APS-induced embryo loss by regulating cellular senescence, proliferation, migration, and angiogenesis.

The pathogenesis of obstetric APS: a 2023 update

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by the persistent presence of antibodies directed against phospholipids and phospholipid-binding proteins that are associated with thrombosis and pregnancy-related morbidity. The latter includes fetal deaths, premature birth and maternal complications. In the early 1990s, a distinct set of autoantibodies, termed collectively antiphospholipid antibodies (aPL), were identified as the causative agents of this disorder. Subsequently histological analyses of the placenta from APS pregnancies revealed various abnormalities, including inflammation at maternal-fetal interface and poor placentation manifested by reduced trophoblast invasion and limited uterine spiral artery remodeling. Further preclinical investigations identified the molecular targets of aPL and the downstream intracellular pathways of key placental cell types. While these discoveries suggest potential therapeutics for this disorder, definitive clinical trials have not been completed. This concise review focuses on the recent developments in the field of basic and translational research pursuing novel mechanisms underlying obstetric APS.

Should we be targeting type 1 interferons in antiphospholipid syndrome?

Systemic autoimmune diseases are characterized by increased production of type I interferon (IFN-1) and upregulation of IFN-1-inducible genes, suggesting an important role of the IFN-1 pathway in their pathogenesis. Recent studies have demonstrated increased IFN-1 expression in both primary and secondary antiphospholipid syndrome (APS), along with increased toll-like receptor type 9 activity and plasmacytoid dendritic cell function. The increasing knowledge of the association between IFN-1 and APS pathology may provide a rationale for conducting clinical trials to assess the efficacy of IFN-1-targeting drugs in reducing APS-related complications. In this narrative review, we summarize the current knowledge on the role of IFN-1 in APS pathogenesis, explore its clinical implications, and examine the existing evidence regarding therapeutic options that have been investigated to date.

Protection of β2GPI Deficient Mice from Thrombosis Reflects a Defect in PAR3-facilitated Platelet Activation

Background

Antibodies to β2-glycoprotein I (β2GPI) cause thrombosis in antiphospholipid syndrome, however the role of β2GPI itself in regulation of coagulation pathways in vivo is not well understood.

Methods

We developed β2GPI-deficient mice (Apoh -/- ) by deleting exon 2 and 3 of Apoh using CRISPR/Cas9 and compared the propensity of wild-type (WT) and Apoh -/- mice to develop thrombosis using rose bengal and FeCl 3 -induced carotid thrombosis, laser-induced cremaster arteriolar injury, and inferior vena cava (IVC) stasis models. We also compared tail bleeding times and assessed platelet activation in WT and Apoh -/- mice in the absence and presence of exogenous β2GPI.

Results

Compared to WT littermates, Apoh -/- mice demonstrated a prolonged time to occlusion of the carotid artery after exposure to rose bengal or FeCl 3 , and reduced platelet and fibrin accumulation in cremasteric arterioles after laser injury. Similarly, significantly smaller thrombi were retrieved from the IVC of Apoh -/- mice 48 hours after IVC occlusion. The activated partial thromboplastin time (aPTT) and prothrombin time, as well as aPTT reagent- and tissue factor-induced thrombin generation times using plasma from Apoh -/- and WT mice revealed no differences. However, we observed significant prolongation of tail bleeding in Apoh -/- mice, and reduced P-selectin expression and binding of fibrinogen to the activated α2bβ3 integrin on platelets from these mice after stimulation with low thrombin concentrations; these changes were reversed by exogenous β2GPI. An antibody to PAR3 blocked thrombin-induced activation of WT, but not Apoh -/- platelets, as well as the ability of β2GPI to restore the activation response of Apoh -/- platelets to thrombin. β2GPI deficiency did not affect platelet activation by a PAR4-activator peptide, or ADP.

Conclusions

In mice, β2GPI may mediate procoagulant activity by enhancing the ability of PAR3 to present thrombin to PAR4, promoting platelet activation at low thrombin concentrations.

Key Points

β2GPI deficient mice are protected from experimental arterial, venous, and microvascular thrombosis.β2GPI deficient mice display prolonged tail bleeding times and reduced PAR3-facilitated platelet activation by low concentrations of thrombin.

The therapeutic age of the neonatal Fc receptor

IgGs are essential soluble components of the adaptive immune response that evolved to protect the body from infection. Compared with other immunoglobulins, the role of IgGs is distinguished and enhanced by their high circulating levels, long half-life and ability to transfer from mother to offspring, properties that are conferred by interactions with neonatal Fc receptor (FcRn). FcRn binds to the Fc portion of IgGs in a pH-dependent manner and protects them from intracellular degradation. It also allows their transport across polarized cells that separate tissue compartments, such as the endothelium and epithelium. Further, it is becoming apparent that FcRn functions to potentiate cellular immune responses when IgGs, bound to their antigens, form IgG immune complexes. Besides the protective role of IgG, IgG autoantibodies are associated with numerous pathological conditions. As such, FcRn blockade is a novel and effective strategy to reduce circulating levels of pathogenic IgG autoantibodies and curtail IgG-mediated diseases, with several FcRn-blocking strategies on the path to therapeutic use. Here, we describe the current state of knowledge of FcRn-IgG immunobiology, with an emphasis on the functional and pathological aspects, and an overview of FcRn-targeted therapy development.

Olfactory reference plus Truman symptoms in one patient with Gilbert syndrome and antiphospholipid antibodies (Hughes disease) secondary to probable chronic Lyme neuroborreliosis

After reading an article in the journal, regarding affective disorders in patients with rare illnesses, the authors would like to discuss a case of non-affective psychosis, presenting with olfactory reference and Truman symptoms, in a patient with three unusual conditions: Gilbert disease, Hughes syndrome and Lyme neuroborreliosis.

Choice of anticoagulation in patients with low risk antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an acquired hypercoagulable state necessitating long-term anticoagulation for secondary thrombosis prevention. Anticoagulation guidelines are predominantly based on data in high risk, triple positive patients, and favor Vitamin K antagonists over other forms of anticoagulation. The efficacy of alternative anticoagulants for secondary thrombosis prevention in low risk, single and double positive APS remains uncertain. This study aimed to assess the incidence of recurrent thrombosis and major bleeding for patient with low risk APS on long-term anticoagulation. We performed a retrospective cohort study of patients who met revised criteria for thrombotic APS between January, 2001 and April, 2021 and received care through the Lifespan Health System. Primary outcomes included recurrent thrombosis and WHO Grades 3 and 4 major bleeding. A total of 190 patients were followed over a median duration of 3.1 years. At time of APS diagnosis, 89 patients were treated with warfarin and 59 patients with a direct oral anticoagulant (DOAC). There were similar rates of recurrent thrombosis in low risk patients on warfarin versus DOACs (adjusted IRR 6.91; 95% CI 0.90-53.40, p = 0.064). Major bleeding events only occurred in low risk patients on warfarin (n = 8, log-rank p = 0.13). In conclusion, despite the choice of anticoagulation, patients with low risk APS had similar rates of recurrent thrombosis suggesting DOACs may be a potential treatment option for this cohort. There was a non-significant increase in major bleeding rates in low risk patients on warfarin versus DOACs. Study limitations include a retrospective study design and small event numbers.

An update on the biologics for the treatment of antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by thrombosis and pregnancy morbidity with the persistent presence of antiphospholipid antibodies (aPLs). Although anticoagulation is the primary treatment for APS, it fails in approximately 20-30% of obstetric APS cases and more than 30% of thrombotic APS cases. Therefore, there is a need for new, targeted treatments beyond anticoagulants. Biologics, such as rituximab and eculizumab, have been recommended for refractory catastrophic APS. This review focuses on the recent advancements in the pathogenesis of APS and explores the potential of targeted treatments, including eculizumab, rituximab, belimumab, daratumumab, obinutuzumab, and anti-TNF-α antibodies, for APS management.

A Post-Pandemic Enigma: The Cardiovascular Impact of Post-Acute Sequelae of SARS-CoV-2

COVID-19 has become the first modern-day pandemic of historic proportion, affecting >600 million individuals worldwide and causing >6.5 million deaths. While acute infection has had devastating consequences, postacute sequelae of SARS-CoV-2 infection appears to be a pandemic of its own, impacting up to one-third of survivors and often causing symptoms suggestive of cardiovascular phenomena. This review will highlight the suspected pathophysiology of postacute sequelae of SARS-CoV-2, its influence on the cardiovascular system, and potential treatment strategies.

Bilateral pulmonary embolism associated with peripheral blood eosinophilia and positive antiphospholipid antibodies in a patient with cellulitis

Key Clinical Message

This report described the pathophysiology, diagnostic workup, and management of thrombosis possibly associated with peripheral blood eosinophilia and transient positive antiphospholipid antibodies in the setting of cellulitis.

Abstract

Peripheral blood eosinophilia is a risk factor for thrombosis and the presence of other prothrombotic factors such as antiphospholipid antibodies can potentiate that risk. The authors present a case of acute pulmonary embolism which developed at the peak of eosinophilia, later found to have transient positive antiphospholipid antibodies in a male patient with right lower limb cellulitis and a history of intravenous drug abuse. This report illustrates the pathophysiology, diagnosis workup, and therapeutic options of thrombosis possibly associated with peripheral blood eosinophilia and positive antiphospholipid antibodies, which include anticoagulants, corticosteroids, and immunosuppressants. Clinicians should be aware of this possible association which may guide the choice and duration of anticoagulants. Although direct oral anticoagulants are effective anticoagulants in various thromboembolic events, studies showed unfavorable outcomes for their use in antiphospholipid syndrome.

Prevention, Diagnostics and Treatment of Deep Vein Thrombosis. Russian Experts Consensus

The guidelines are developed in accordance with the requirements of the Ministry of Health of the Russian Federation by the all-Russian public organization «Association of Phlebologists of Russia» with participation of the Association of Cardiovascular Surgeons of Russia, the Russian Society of Surgeons, the Russian Society of Angiologists and Vascular Surgeons, the Association of Traumatologists and Orthopedists of Russia, the Association of Oncologists of Russia, the Russian Society of Clinical Oncology, Russian Society of Oncohematologists, Russian Society of Cardiology, Russian Society of Obstetricians and Gynecologists.

An Antiphospholipid Antibody Profile as a Biomarker for Thrombophilia in Systemic Lupus Erythematosus

Despite recent advances in treatment and significant improvements in prognosis, thrombosis remains the major cause of death in systemic lupus erythematosus (SLE). Antiphospholipid antibodies (aPL) are the main triggers of thrombosis in patients with SLE, with a frequency of approximately 30-40%. Lupus anticoagulant, anticardiolipin, and anti-β2-glycoprotein I antibodies, which are included in the criteria for antiphospholipid syndrome, and 'non-criteria' aPL such as anti-phosphatidylserine/prothrombin complex antibodies, are risk factors for thrombosis in patients with SLE. Multiple positivity for aPL is also associated with an increased risk of thrombosis, and scores calculated from aPL profiles can predict the risk of developing thrombosis. Although there is insufficient evidence for treatment, aPL-positive SLE patients should/may be treated with anticoagulants and/or low-dose aspirin as appropriate. This review summarises the evidence on the clinical significance of the aPL profile as a biomarker of thrombophilia in patients with SLE.

Hematological manifestations of antiphospholipid syndrome: Going beyond thrombosis

Thrombotic complications are a hallmark of antiphospholipid syndrome (APS). These vascular - arterial, venous, and/or small vessel - complications are well described and known to hematologists and healthcare providers caring for patients with this disease. In this review, we shed light on other hematological manifestations of the disease, including bleeding, thrombocytopenia, autoimmune hemolytic anemia, and thrombotic microangiopathy syndromes. While these manifestations are not bona fide clinical criteria for the diagnosis of APS, they frequently interact and contribute to the complexity of clinical management of APS.

A Comprehensive Review of Risk Factors for Venous Thromboembolism: From Epidemiology to Pathophysiology

Venous thromboembolism (VTE) is the third most common cause of death worldwide. The incidence of VTE varies according to different countries, ranging from 1-2 per 1000 person-years in Western Countries, while it is lower in Eastern Countries (<1 per 1000 person-years). Many risk factors have been identified in patients developing VTE, but the relative contribution of each risk factor to thrombotic risk, as well as pathogenetic mechanisms, have not been fully described. Herewith, we provide a comprehensive review of the most common risk factors for VTE, including male sex, diabetes, obesity, smoking, Factor V Leiden, Prothrombin G20210A Gene Mutation, Plasminogen Activator Inhibitor-1, oral contraceptives and hormonal replacement, long-haul flight, residual venous thrombosis, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, trauma and fractures, pregnancy, immobilization, antiphospholipid syndrome, surgery and cancer. Regarding the latter, the incidence of VTE seems highest in pancreatic, liver and non-small cells lung cancer (>70 per 1000 person-years) and lowest in breast, melanoma and prostate cancer (<20 per 1000 person-years). In this comprehensive review, we summarized the prevalence of different risk factors for VTE and the potential molecular mechanisms/pathogenetic mediators leading to VTE.

Variability among commercial batches of normal pooled plasma in lupus anticoagulant testing

INTRODUCTION

Lupus anticoagulant (LA) testing requires normal pooled plasma (NPP) in performing mixing studies and can be used for normalized ratios of clotting times (CTs). The aims were to demonstrate whether significant differences in clotting times between two batches of a same commercial NPP (CRYOcheck™) directly affect NPP-based cut-off values.

METHODS

Diluted Russell Viper venom time (DRVVT) and activated partial thromboplastin time (aPTT) were used for LA testing. Screening, mixing and confirm tests were performed with Stago® instruments and reagents. Two batches of commercial NPP (A1291 and A1301 from CRYOcheck™; frozen) were compared in the determination of cut-off values. Cut-off values were defined as 99th percentile values of 60 healthy donors and compared with Mann-Whitney U test.

RESULTS

Cut-off values obtained with the two NPP batches were significantly different for DRVVT (screen normalized ratio: 1.09 vs. 1.24, screen mix: 41.9 s vs. 38.9 s; index of circulating anticoagulant: 5.0 vs. 8.4; all had p-value <.001). On the contrary, no significant differences were observed for aPTT (screen normalized ratio: 1.32 vs. 1.34; p-value = .4068, screen mix: 37.8 s vs. 38.1 s; p-value = .1153) except for index of circulating anticoagulant: 9.6 versus 10.4 (p-value <.05).

CONCLUSION

This study demonstrates that differences between two commercial NPP batches produced by a same manufacturer influenced LA cut-off values used for mixing studies and normalized ratios. Adequate cut-off setting, taking into account NPP CTs, is important to provide accurate conclusion about the presence or absence of a LA and avoid potential clinical impact.

Inactivation of Yes-Associated Protein Mediates Trophoblast Dysfunction: A New Mechanism of Pregnancy Loss Associated with Anti-Phospholipid Antibodies?

Pregnancy morbidity induced by anti-phospholipid antibodies (aPL+/PM+) is mainly thought to arise from placental abnormalities. We attempted to investigate the effect of aPL on the activity of Yes-associated protein (YAP) in the trophoblast and how YAP regulated human trophoblasts function. Thus, HTR-8 cells were treated with IgG purified from aPL+/PM+ women or normal controls. We found that aPL+/PM+ IgG impacted YAP activity via abrogating YAP expression. Further investigation of the anti-β2GPI-IgG/β2GPI complex showed an inhibition of nuclear YAP level and translocation in a dose-dependent manner, which might be rescued by progesterone in HTR-8 cells. YAP overexpression or knockdown HTR-8 cells were established for the evaluation of cell function and related gene expression in vitro. Loss of YAP arrested cell cycles in the G2/M phase, accelerated cell apoptosis by increasing the ratio of Bax/Bcl2, and disrupted MMP2/9-mediated cell migration and angiogenesis tube formation by VEGF. These findings support a new mechanism of PM associated with aPL through which YAP inactivation induced by aPL perturbs the trophoblast cell cycle, apoptosis, migration, and angiogenesis, finally developing into pregnancy failure.

Anticardiolipin and/or anti-β2-glycoprotein-I antibodies are associated with adverse IVF outcomes

OBJECTIVE

The purpose of the study is to evaluate the effects of anticardiolipin (aCL) and/or anti-β2-glycoprotein-I (aβ2GPI) antibodies, namely antiphospholipid antibodies (aPL), on in vitro fertilization (IVF) outcomes.

MATERIALS AND METHODS

The study group comprised infertile women with aPL undergoing IVF-ET cycles. Controls were infertile women with tubal etiology without aPL. The impact of aPL on reproductive outcomes, such as oocyte quality, embryo quality, and implantation capacity, was compared between the study group and controls. Additionally, peripheral blood T cell subsets, such as T helper (Th)1, Th2, Th17, and T regulatory (Treg) cells and cytokines, were analyzed by the flow cytometry. Differences between the study group and controls were analyzed.

RESULTS

A total of 132 infertile women, including 44 women with aPL, and 88 controls were sequentially recruited for this study. Women with aPL had lower numbers of total and perfect/available embryos and lower rates of MII oocytes, blastocyst formation, perfect and available embryos, implantation, clinical pregnancy, and take-home baby. Additionally, imbalanced Th1/Th2 and Th17/Treg ratios, significantly higher levels of serum IL-2, TNF-α, IFN-γ, and IL-17A, and a significantly lower serum IL-4 were noticed in women with aPL compared to controls.

CONCLUSION

Women with aPL such as aCL and/or aβ2GPI antibodies were associated with adverse IVF outcomes. Early screening for aPL and appropriate consultation for couples undergoing IVF should be considered. In addition, underlying immunopathology and inflammatory immune mechanisms associated with aPL should be further explored.