Obstetric and vascular antiphospholipid syndrome: same antibodies but different diseases?

Bulk T-cell receptor sequencing confirms clonality in obstetric antiphospholipid syndrome and may as a potential biomarker

The heterogeneity of the T cell receptor (TCR) repertoire critically influences the autoimmune response in obstetric antiphospholipid syndrome (OAPS) and is intimately associated with the prophylaxis of autoimmune disorders. Investigating the TCR diversity patterns in patients with OAPS is thus of paramount clinical importance. This investigation procured peripheral blood specimens from 31 individuals with OAPS, 21 patients diagnosed with systemic lupus erythematosus (SLE), and 22 healthy controls (HC), proceeding with TCR repertoire sequencing. Concurrently, adverse pregnancy outcomes in the OAPS cohort were monitored and documented over an 18-month timeframe. We paid particular attention to disparities in V/J gene utilisation and the prevalence of shared clonotypes amongst OAPS patients and the comparative groups. When juxtaposed with observations from healthy controls and SLE patients, immune repertoire sequencing disclosed irregular T- and B-cell profiles and a contraction of diversity within the OAPS group. Marked variances were found in the genomic rearrangements of the V gene, J gene, and V/J combinations. Utilising a specialised TCRβ repertoire, we crafted a predictive model for OAPS classification with robust discriminative capability (AUC = 0.852). Our research unveils alterations in the TCR repertoire among OAPS patients for the first time, positing potential covert autoimmune underpinnings. These findings nominate the TCR repertoire as a prospective peripheral blood biomarker for the clinical diagnosis of OAPS and may offer valuable insights for advancing the understanding of OAPS immunologic mechanisms and prognostic outcomes.

Antiphospholipid antibodies and the risk of adverse pregnancy outcomes in patients with systemic lupus erythematosus: a systematic review and meta-analysis

OBJECTIVE

This article aims to evaluate the magnitude of adverse pregnancy outcomes (APOs) risks associated with different antiphospholipid antibody (aPL) profiles in women with systemic lupus erythematosus (SLE).

METHODS

Multiple databases were investigated to identify articles that explored the relationship between aPLs and APOs in SLE patients. A random effects model was used for calculating pooled odds ratios (OR). Stata version 15.0 was utilized to conduct the meta-analysis.

RESULTS

There were 5234 patients involved in 30 studies. Overall aPL was linked to an increased incidence of any kind of APOs, fetal loss, and preterm birth. Any kind of APOs and preterm delivery were more common in patients with lupus anticoagulant (LA) positive. Anticardiolipin antibody (aCL) was associated with an increased risk of any kind of APOs and fetal loss. The association between aCL-IgM and fetal loss was also significant. Patients with anti-beta2-glycoprotein1 antibody (antiβ2GP1) positivity had an increased risk of fetal loss.

CONCLUSIONS

Both LA and aCL were risk factors of APOs in patients with SLE. Not only ACL, particularly aCL-IgM, but antiβ2GP1 were associated with an increased risk of fetal loss, while LA appeared to indicate the risk of preterm birth.PROSPERO (CRD42023388122).

Obstetric antiphospholipid syndrome carries an increased lifetime risk for obstetric and thrombotic complications-a population-based study

Background

Antiphospholipid syndrome (APS) can present with either a thromboembolic event (thrombotic APS, TAPS) or an obstetric complication (obstetric APS, OAPS). Data on long-term complications in the different APS phenotypes are limited.

Objectives

We aimed to compare obstetric history, antiphospholipid antibody profiles, obstetric and thromboembolic complications, and pregnancy outcomes between TAPS and OAPS.

Methods

This retrospective cohort study included women who delivered singleton pregnancies between 1998 and 2020. One hundred sixteen thousand four hundred nine women were included, resulting in 320,455 deliveries. Among the included patients, 71 were diagnosed with APS, 49 were classified as OAPS, and 22 as TAPS. The demographics, obstetric, neonatal, and thrombotic outcomes were compared among TAPS, OAPS, and the general obstetric population.

Results

OAPS patients had an increased risk of thrombotic events compared with the general obstetric population (odds ratio [OR] 18.0; 95% CI, 8.7-37.2). In pregnancies following the diagnosis of APS, despite standard antithrombotic treatment, OAPS patients exhibited an elevated risk of placenta-related and neonatal complications compared with the general obstetric population (late fetal loss [adjusted OR {aOR}, 15.3; 95% CI, 0.5-27.5], stillbirth [aOR, 5.9; 95% CI, 2.2-15.4], placental abruption [aOR, 4.8; 95% CI, 1.5-15.3], preeclampsia [aOR, 4.4; 95% CI, 2.5-7.7], fetal growth restriction [aOR, 4.3; 95% CI, 8.5-27.5], small for gestational age neonate [aOR, 4.0; 95% CI, 2.4-6.6], and low Apgar scores [Apgar'1: aOR, 2.6; 95% CI, 1.3-10.4; Apgar'5: aOR, 3.7; 95% CI, 1.3-10.4]). TAPS patients exhibited increased risk of preeclampsia (aOR, 3.1; 95% CI, 1.2-8).

Conclusion

OAPS patients exhibit a heightened risk of thrombotic events compared with the general obstetric population. Despite treatment, OAPS and TAPS still presented obstetric complications. These findings, after confirmation in prospective studies, need to be taken into consideration when planning the treatment approach for these patients.

Loss of opportunities in the diagnosis and treatment of primary obstetric antiphospholipid syndrome (POAPS): from theory to reality

OBJECTIVES

(I) To identify and measure the clinical consequences of a delayed diagnosis in patients with primary obstetric antiphospholipid syndrome (POAPS), in terms of time and events associated to antiphospholipid syndrome (APS), and (II) to evaluate the impact of their treatment status on perinatal outcomes, before and after diagnosis.

METHODS

This retrospective multicentre study included 99 POAPS women who were separated in two groups of timelines based on their diagnostic status: group 1: women who met the clinical criteria for POAPS; group 2: included the same patients from group 1 since they meet the laboratory criteria for APS. In group 1, we assessed the following variables: obstetric events, thrombotic events and time (years) to diagnosis of APS. We also compared perinatal outcomes between patients in group 1 vs. group 2. Women in group 2 were treated with standard of care for POAPS. Simple and multivariable logistic regression analyses were performed.

RESULTS

Regarding the impact of the delay on diagnosis, a total of 87 APS-related events were recorded: 46 miscarriages, 32 foetal losses and 9 premature deliveries before the 34th week due to preeclampsia, and one thrombosis. The estimated rate of preventable events was 20.58 per year/100 patients. The mean diagnostic delay time was 4.27 years. When we compared both groups during pregnancy, we found that patients in group 1 (no treatment) had a higher association with pregnancy losses [OR = 6.71 (95% CI: 3.59-12.55), p < 0.0001].

CONCLUSION

Our findings emphasize the negative impact of POAPS underdiagnosis on patient health and the critical importance of a timely intervention to improve pregnancy outcomes. Key Points •Our study shows the relevance of underdiagnosis on primary obstetric antiphospholipid syndrome (POAPS). •These patients presented a high risk of APS-related events with each passing year. •Shorter diagnostic delay time was observed in the reference centres.

Arterial stiffness tested by pulse wave velocity and augmentation index for cardiovascular risk stratification in antiphospholipid syndrome

OBJECTIVES

Cardiovascular disease is a major cause of morbidity and mortality in Antiphospholipid syndrome (APS). Arterial stiffness (ArS) has emerged as a predictor of future cardiovascular events in the general population. We aimed to assess ArS in patients with thrombotic APS versus diabetes mellitus (DM) and healthy controls (HC) and identify predictors of increased ArS in APS.

METHODS

ArS was evaluated by carotid-femoral pulse wave velocity (cfPWV) and augmentation index normalized to 75 beats/min (AIx@75) using the SphygmoCor device. Participants also underwent carotid/femoral ultrasound for atherosclerotic plaque detection. We used linear regression to compare ArS measures among groups and assess ArS determinants in the APS group.

RESULTS

We included 110 patients with APS (70.9% female, mean age 45.4 years), 110 DM patients and 110 HC, all age/sex matched. After adjustment for age, sex, cardiovascular risk factors and plaque presence, APS patients exhibited similar cfPWV [β = -0.142 (95% CI -0.514, 0.230), p = 0.454] but increased AIx@75 [β = 4.525 (95% CI 1.372, 7.677), p = 0.005] compared with HC and lower cfPWV (p < 0.001) but similar AIx@75 (p = 0.193) versus DM patients. In the APS group, cfPWV was independently associated with age [β = 0.056 (95% CI 0.034, 0.078), p < 0.001], mean arterial pressure (MAP) [β = 0.070 (95% CI 0.043, 0.097), p < 0.001], atherosclerotic femoral plaques [β = 0.732 (95% CI 0.053, 1.411), p = 0.035] and anti-β2-glycoprotein I IgM positivity [β = 0.696 (95% CI 0.201, 1.191), p = 0.006]. AIx@75 was associated with age [β = 0.334 (95% CI 0.117, 0.551), p = 0.003], female sex [β = 7.447 (95% CI 2.312, 12.581), p = 0.005] and MAP [β = 0.425 (95% CI 0.187, 0.663), p = 0.001].

CONCLUSION

APS patients exhibit elevated AIx@75 vs HC and similar to DM patients, indicating enhanced arterial stiffening in APS. Given its prognostic value, ArS evaluation may help to improve cardiovascular risk stratification in APS.

Recurrent miscarriage and low-titer antiphospholipid antibodies

OBJECTIVE

To evaluate the clinical features and pregnancy outcomes in patients experiencing recurrent miscarriage (RM) with either low-titer or medium-high titer positivity of antiphospholipid antibodies (aPL).

METHODS

A retrospective review of medical records was conducted for patients with aPL positivity and recurrent miscarriage between 2018 and 2022. The clinical features, treatment strategies, outcomes were compared between the patients with low (n = 92) and medium (n = 32) titer of aPL.

RESULTS

A total of 118 patients, resulting in 124 obstetric episodes (pregnancies), with a mean age of 33. 15 ± 4.56 and 31.47 ± 4.41 years between the two groups. The low-titer group exhibited a higher frequency of anti-cardiolipin antibodies IgM (P < 0.001), whereas the medium-high titer group demonstrated a higher frequency of anti-β2-glycoprotein 1 antibodies IgG (P < 0.001) and IgM (P = 0.032). Moreover, the medium-high titer group displayed a significantly elevated erythrocyte sedimentation rate compared to the low-titer group (P < 0.05). In the low-titer group, 71 patients (77.2%) received appropriate treatment, resulting in 48 live births (67.6%) and 23 repeat abortions (32.4%). In the medium-high titer group, 29 patients (90.6%) received relevant treatment, leading to 23 live births (79.3%) and 6 repeat abortions (20.7%). No significant differences were observed in live births or maternal-fetal complications between the two groups (all P > 0.05).

CONCLUSION

Noteworthy distinctions in laboratory parameters were identified between the low-titer and medium-high titer groups. However, when appropriately treated, the fetal-maternal outcomes were comparable in both groups. Timely intervention by clinicians is imperative to enhance pregnancy outcomes in patients experiencing recurrent miscarriage with low levels of aPL. Key Points • This study challenges the conventional belief that only the higher antiphospholipid antibodies (aPL) titers directly correlated with worse pregnancy outcomes, which emphasized the importance of patients with low titer positive aPL-positive RM. • The results underscore the need for timely intervention in women with low titer aPL-positive RM, as it leads to favorable maternal-fetal outcomes.

The prevalence and incidence of thrombotic primary antiphospholipid syndrome in adults aged 18-49 years: A population-based study in a mountain community in northern Italy

OBJECTIVE

To estimate prevalence and incidence of thrombotic Primary Antiphospholipid Syndrome (PAPS) in the general population aged 18-49 years.

METHODS

The study was carried out in Valtrompia, a valley in northern Italy, in 2011-2015. The identification of PAPS cases leveraged three integrated sources: 1) Rheumatology Unit at the University Hospital; 2) General Practitioners; 3) hospital discharge codes of patients admitted for thrombotic events.

RESULTS

Prevalence and incidence were estimated as 22.9 (95% C.I. 11.4-41.0) and 5.0 (2.6-8.7) cases per 100,000 individuals, respectively. The estimates were 28.3 and 4.8, and 17.2 and 5.1 in males and females, respectively. The type of disease onset was mainly of arterial type in men and venous in women.

CONCLUSIONS

Thrombotic PAPS was found to be a rare disease in this population-based study. Prevalence and incidence were not significantly different between males and females aged 18-49 years, but a different type of onset was observed.

Antiphospholipid syndrome pathogenesis in 2023: an update of new mechanisms or just a reconsideration of the old ones?

Antibodies against phospholipid (aPL)-binding proteins, in particular, beta 2 glycoprotein I (β2GPI), are diagnostic/classification and pathogenic antibodies in antiphospholipid syndrome (APS). β2GPI-aPL recognize their target on endothelium and trigger a pro-thrombotic phenotype which is amplified by circulating monocytes, platelets and neutrophils. Complement activation is required as supported by the lack of aPL-mediated effects in animal models when the complement cascade is blocked. The final result is a localized clot. A strong generalized inflammatory response is associated with catastrophic APS, the clinical variant characterized by systemic thrombotic microangiopathy. A two-hit hypothesis was suggested to explain why persistent aPL are associated with acute events only when a second hit allows antibody/complement binding by modulating β2GPI tissue presentation. β2GPI/β2GPI-aPL are also responsible for obstetric APS, being the molecule physiologically present in placental/decidual tissues. Additional mechanisms mediated by aPL with different characteristics have been reported, but their diagnostic/prognostic value is still a matter of research.

Pregnancy in antiphospholipid syndrome: what should a rheumatologist know?

This review focuses on the management of reproductive issues in women who have antiphospholipid syndrome (APS) or are carriers of antiphospholipid antibodies (aPL). The importance of aPL detection during preconception counselling relies on their pathogenic potential for placental insufficiency and related obstetric complications. The risk of adverse pregnancy outcomes can be minimized by individualized risk stratification and tailored treatment aimed at preventing placental insufficiency. Combination therapy of low-dose acetylsalicylic acid and heparin is the mainstay of prophylaxis during pregnancy; immunomodulation, especially with hydroxychloroquine, should be considered in refractory cases. Supplementary ultrasound surveillance is useful to detect fetal growth restriction and correctly tailor the time of delivery. The individual aPL profile must be considered in the stratification of thrombotic risk, such as during assisted reproduction techniques requiring hormonal ovarian stimulation or during the follow-up after pregnancy in order to prevent the first vascular event.

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.

Trophoblast Cell Function in the Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a complex thrombo-inflammatory autoimmune disease characterized by the presence of antiphospholipid antibodies (aPL). Women with APS are at high risk of recurrent early pregnancy loss as well as late obstetrical complications-premature birth due to placental insufficiency or severe preeclampsia. Accumulating evidence implies that vascular thrombosis is not the only pathogenic mechanism in obstetric APS, and that the direct negative effect of aPL on the placental cells, trophoblast, plays a major role. In this review, we summarize the current findings regarding the potential mechanisms involved in aPL-induced trophoblast dysfunction. Introduction on the APS and aPL is followed by an overview of the effects of aPL on trophoblast-survival, cell function and aPL internalization. Finally, the implication of several non-coding RNAs in pathogenesis of obstetric APS is discussed, with special emphasis of their possible role in trophoblast dysfunction and the associated mechanisms.

Obesity and recurrent miscarriage: The interconnections between adipose tissue and the immune system

Currently, obesity is considered a global public health problem. It is the main risk factor for noncommunicable diseases and reproductive complications, such as recurrent miscarriage (RM). RM affects approximately 1% of couples of reproductive age, and recent studies suggest that its prevalence is increasing. Immunological abnormalities may be responsible for a significant number of cases of unexplained RM. Obesity is recognized as a chronic low-grade inflammatory condition. The accumulation of fat in obese adipose tissue promotes changes in the local and systemic immune response. Adipokines, exosomes, micro-RNAs, lipids, and other factors released or secreted by adipose tissue are responsible for the interconnection between obesity and the immune system. Obesity-induced dysregulation of the innate and acquired immune response is also involved in the immunopathology of pregnancy loss in patients with unexplained RM. Therefore, understanding the communication pathways between maternal adipose tissue and the immune response in women living with obesity and RM is an important objective. Thus, diagnostic tools and new immunomodulatory therapies may be proposed for the management of patients with concurrent obesity and RM.

Modulation of the activation of endothelial nitric oxide synthase and nitrosative stress biomarkers by aspirin triggered lipoxins: A possible mechanism of action of aspirin in the antiphospholipid syndrome

PROBLEM

Antiphospholipid syndrome (APS) is characterized by the clinical manifestation of vascular thrombosis (VT) or pregnancy morbidity (PM) and antiphospholipid antibodies (aPL) that can modify the nitric oxide production. Low-dose aspirin is used in the prevention and treatment of diverse alterations of pregnancy. One of the mechanisms of action of aspirin is to induce the production of aspirin-triggered-lipoxins (ATL). The aim of this study was to evaluate the modulatory effect of ATL over the activation of endothelial nitric oxide synthase (eNOS) and nitrosative stress biomarkers induced by aPL.

METHODS

We used polyclonal IgG and sera from women with aPL and PM/VT or VT only, and from women with PM only and positive for non-criteria aPL (SN-OAPS). In these sera, biomarkers of nitrosative stress (nitrites and nitrotyrosine) were measured. The protein expression of nitrotyrosine and the phosphorylation of eNOS (at Ser1177) were estimated in human umbilical vein endothelial cells (HUVECs) stimulated with polyclonal IgG with or without ATL.

RESULTS

Women with SN-OAPS showed increased circulating levels of nitrites and nitrotyrosine. Likewise, polyclonal IgG from either SN-OAPS or VT patients stimulated nitrotyrosine expression in HUVECs. ATL decreased the nitrotyrosine expression induced by polyclonal IgG from the SN-OAPS group. ATL also recovered the reduced eNOS phosphorylation at Ser1177 in HUVECs stimulated with polyclonal IgG from women with PM/VT or SN-OAPS.

CONCLUSIONS

Increased nitrosative stress present in serum of women with SN-OAPS is associated with IgG-mediated impaired endothelial NO synthesis in endothelial cells. ATL prevent these cellular changes.

High-throughput sequencing technology facilitates the discovery of novel biomarkers for antiphospholipid syndrome

Antiphospholipid syndrome (APS) is characterized by arterial and venous thrombosis and/or morbid pregnancy, accompanied by persistent antiphospholipid antibody (aPL) positivity. However, due to the complex pathogenesis of APS and the large individual differences in the expression of aPL profiles of patients, the problem of APS diagnosis, prognosis judgment, and risk assessment may not be solved only from the antibody level. It is necessary to use new technologies and multiple dimensions to explore novel APS biomarkers. The application of next-generation sequencing (NGS) technology in diseases with a high incidence of somatic mutations, such as genetic diseases and tumors, has been very mature. Thus, we try to know the research and application progress of APS by NGS technology from genome, transcriptome, epigenome and other aspects. This review will describe the related research of NGS technology in APS and provide more reference for the deep understanding of APS-related screening markers and disease pathogenesis.

Interaction between endothelial cell-derived extracellular vesicles and monocytes: A potential link between vascular thrombosis and pregnancy-related morbidity in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease driven by a wide group of autoantibodies primarily directed against phospholipid-binding proteins (antiphospholipid antibodies). APS is defined by two main kinds of clinical manifestations: vascular thrombosis and pregnancy-related morbidity. In recent years, in vitro and in vivo assays, as well as the study of large groups of patients with APS, have led some authors to suggest that obstetric and vascular manifestations of the disease are probably the result of different pathogenic mechanisms. According to this hypothesis, the disease could be differentiated into two parallel entities: Vascular APS and obstetric APS. Thus, vascular APS is understood as an acquired thrombophilia in which a generalised phenomenon of endothelial activation and dysfunction (coupled with a triggering factor) causes thrombosis at any location. In contrast, obstetric APS seems to be due to an inflammatory phenomenon accompanied by trophoblast cell dysfunction. The recent approach to APS raises new issues; for instance, the mechanisms by which a single set of autoantibodies can lead to two different clinical entities are unclear. This review will address the monocyte, a cell with well-known roles in haemostasis and pregnancy, as a potential participant in vascular thrombosis and pregnancy-related morbidity in APS. We will discuss how in a steady state the monocyte-endothelial interaction occurs via extracellular vesicles (EVs), and how antiphospholipid antibodies, by inducing endothelial activation and dysfunction, may disturb this interaction to promote the release of monocyte-targeted procoagulant and inflammatory messages.

Immunology of pregnancy and reproductive health in autoimmune rheumatic diseases. Update from the 11th International Conference on Reproduction, Pregnancy and Rheumatic Diseases

Autoimmune rheumatic diseases (ARD) can affect women and men during fertile age, therefore reproductive health is a priority issue in rheumatology. Many topics need to be considered during preconception counselling: fertility, the impact of disease-related factors on pregnancy outcomes, the influence of pregnancy on disease activity, the compatibility of medications with pregnancy and breastfeeding. Risk stratification and individualized treatment approach elaborated by a multidisciplinary team minimize the risk of adverse pregnancy outcomes (APO). Research has been focused on identifying biomarkers that can be predictive of APO. Specifically, preeclampsia and hypertensive disorders of pregnancy tend to develop more frequently in women with ARD. Placental insufficiency can lead to intrauterine growth restriction and small-for-gestational age newborns. Such APO have been shown to be associated with maternal disease activity in different ARD. Therefore, a key message to be addressed to the woman wishing for a pregnancy and to her family is that treatment with compatible drugs is the best way to ensure maternal and fetal wellbeing. An increasing number of medications have entered the management of ARD, but data about their use in pregnancy and lactation are scarce. More information is needed for most biologic drugs and their biosimilars, and for the so-called small molecules, while there is sufficient evidence to recommend the use of TNF inhibitors if needed for keeping maternal disease under control. Other issues related to the reproductive journey have emerged as "unmet needs", such as sexual dysfunction, contraception, medically assisted reproduction techniques, long-term outcome of children, and they will be addressed in this review paper. Collaborative research has been instrumental to reach current knowledge and the future will bring novel insights thanks to pregnancy registries and prospective studies that have been established in several Countries and to their joint efforts in merging data.

Clinical phenotype, treatment strategy and pregnancy outcome of non-criteria obstetric antiphospholipid syndrome

PROBLEM

To illustrate the clinical features, treatment strategy, and pregnancy outcome of patients with obstetric antiphospholipid syndrome (OAPS), non-criteria obstetric antiphospholipid syndrome (NC-OAPS) METHOD OF STUDY: A single-center nested case-control study was designed. Patients with a diagnosis of OAPS and NC-OAPS were enrolled. The medical history, coagulation status, and antibody profile data were collected. Patients were given standard anticoagulation therapy with or without glucocorticoids (GC) and/or hydroxychloroquine (HCQ) during pregnancy and were observed for their pregnancy outcome.

RESULTS

A total of 47 patients with OAPS and 120 patients with NC-OAPS were finally included, of whom 55 patients met the clinical criteria (subgroup C) and 65 met the laboratory criteria (subgroup L). Pregnancy morbidity showed significant differences: gravida, pregnancy loss in OAPS versus NC-OAPS. The coagulation function was not significantly different between OAPS and NC-OAPS groups, while TT and FIB were significantly higher in the subgroup C. Thromboelastography (TEG) results showed a significantly lower ANGEL in the NC-OAPS group, a higher ANGEL and lower EPL, LY30 in the subgroup L. No differences between groups were observed in treatment strategy. The pregnancy outcomes were not significantly different between NC-OAPS and OAPS groups.

CONCLUSIONS

Clinical and laboratory differences were found between OAPS and NC-OAPS groups in this study. Patients in different subgroups of NC-OAPS could be identified with different clinical phenotypes. A relatively hypercoagulable status existed in the OAPS group compared to NC-OAPS, and also in the subgroup L.

Antiphospholipid Syndrome in Pregnancy: New and Old Pathogenetic Mechanisms

The antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized, according to the Sydney criteria, by the persistent presence of autoantibodies directed against phospholipid-binding proteins associated with thrombosis and/or obstetrical complications. The most frequent complications in obstetric antiphospholipid syndrome are recurrent pregnancy losses and premature birth due to placental insufficiency or severe preeclampsia. In recent years, vascular APS (VAPS) and obstetric APS (OAPS) have been described as two different clinical entities. In VAPS, antiphospholipid antibodies (aPL) interfere with the mechanisms of coagulation cascade and the 'two hit hypothesis' has been suggested to explain why aPL positivity does not always lead to thrombosis. OAPS seems to involve additional mechanisms, such as the direct action of anti-β2 glycoprotein-I on trophoblast cells that can lead to a direct placental functional damage. Furthermore, new actors seem to play a role in the pathogenesis of OAPS, including extracellular vesicles, micro-RNAs and the release of neutrophil extracellular traps. The aim of this review is to investigate the state-of-the-art antiphospholipid syndrome pathogenesis in pregnancy, in order to provide a comprehensive overview of both old and new pathogenetic mechanisms involved in this complex disease.

Beta 2 glycoprotein I and neutrophil extracellular traps: Potential bridge between innate and adaptive immunity in anti-phospholipid syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by recurrent vascular thrombosis and miscarriages in the absence of known causes. Antibodies against phospholipid-binding proteins (aPL) are pathogenic players in both clotting and pregnancy APS manifestations. There is sound evidence that antibodies specific for beta2 glycoprotein I (β2GPI) trigger thrombotic and pregnancy complications by interacting with the molecule on the membranes of different cell types of the coagulation cascade, and in placenta tissues. In addition to the humoral response against β2GPI, both peripheral and tissue CD4⁺ β2GPI-specific T cells have been reported in primary APS as well as in systemic lupus erythematosus (SLE)-associated APS. While adaptive immunity plays a clear role in APS, it is still debated whether innate immunity is involved as well. Acute systemic inflammation does not seem to be present in the syndrome, however, there is sound evidence that complement activation is crucial in animal models and can be found also in patients. Furthermore, neutrophil extracellular traps (NETs) have been documented in arterial and venous thrombi with different etiology, including clots in APS models. Keeping in mind that β2GPI is a pleiotropic glycoprotein, acting as scavenger molecule for infectious agents and apoptotic/damaged body constituents and that self-molecules externalized through NETs formation may become immunogenic autoantigens, we demonstrated β2GPI on NETs, and its ability to stimulate CD4⁺β2GPI-specific T cells. The aim of this review is to elucidate the role of β2GPI in the cross-talk between the innate and adaptive immunity in APS.

Soluble LILRA3 is aberrantly expressed in antiphospholipid syndrome (APS) and is a potential marker of thrombotic APS

OBJECTIVE

Leucocyte immunoglobulin-like receptor A3 (LILRA3) belongs to a family of leucocyte receptors. Our previous study reported LILRA3 transcripts were markedly upregulated in neutrophils from patients with APS. We undertook this study to investigate clinical implications of LILRA3 in APS and its potential role in APS-associated thrombosis.

METHODS

Two independent cohorts were studied. The first consisted of 294 APS patients, 48 asymptomatic aPL carriers and 150 healthy controls (HCs) from Peking University People's Hospital. The second included 99 APS patients, 25 aPL carriers and 40 HCs from United States APS centres. Serum or plasma concentrations of LILRA3 and MPO-DNA complexes were measured. Additionally, 35 patients with thrombotic APS (tAPS) were evaluated to determine potential effects of immunosuppressive therapy on serum concentrations of LILRA3 and MPO-DNA complexes.

RESULTS

Both positivity and serum concentration of LILRA3 were significantly increased in APS patients, especially in those with tAPS. LILRA3-positive tAPS patients displayed more severe thrombotic manifestations. Serum LILRA3 was positively correlated with MPO-DNA complexes in LILRA3-positive tAPS. After immunosuppressive treatment, LILRA3 and MPO-DNA complexes were consistently decreased in tAPS patients. Key findings from the Peking cohort were confirmed in the United States cohort.

CONCLUSION

Our study provides first evidence that LILRA3 is aberrantly expressed in APS, especially in patients with tAPS. Serum LILRA3 correlated with MPO-DNA complexes, and the two indices were consistently decreased in tAPS patients after treatment. LILRA3 may play a role in thrombosis of APS and may serve as a biomarker and/or therapeutic target in tAPS.

Non-Criteria Obstetric Antiphospholipid Syndrome: How Different Is from Sidney Criteria? A Single-Center Study

This study aims to compare the demographic characteristics, clinical features, serology, and fetal-maternal outcomes between women with obstetric antiphospholipid syndrome (APS) and those with non-criteria (NC)-APS and seronegative (SN)-APS. Two-hundred and sixty-three women with APS obstetric morbidity ever pregnant were included. Of those, 66 met the APS classification criteria, 140 were NC-APS, and 57 were SN-APS. Patients with other autoimmune diseases were excluded. Adverse pregnancy outcomes (APO) included early pregnancy loss, fetal death, preeclampsia, abruptio placentae, and preterm birth. The mean age of the study group was 33.6 ± 5.3 years, and patients were followed up for 129.5 ± 81.9 months. In the NC-APS group, 31 (22.1%) did not fulfill clinical and serological criteria (Subgroup A), 49 (35%) did meet clinical but not serologic criteria (Subgroup B), and 60 (42.9%) fulfilled the serologic criteria but not the clinical ones (Subgroup C). The cardiovascular risk burden was higher in the APS group, due to a higher proportion of smoking. Patients with criteria APS received more intensive treatment than patients in the other study groups. The addition of standard of care (SoC) treatment significantly improved live birth and decreased APO in all groups. Significant clinical differences were observed between the study groups. However, when treated with SoC, fetal-maternal outcomes were similar, with a significant improvement in live births and a decrease in APO. Risk stratification in patients with obstetric morbidity associated with APS can help individualize their treatment.

Placental damage in pregnancies with systemic lupus erythematosus: A narrative review

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease of unknown cause, which mainly affects women of childbearing age, especially between 15 and 55 years of age. During pregnancy, SLE is associated with a high risk of perinatal morbidity and mortality. Among the most frequent complications are spontaneous abortion, fetal death, prematurity, intrauterine Fetal growth restriction (FGR), and preeclampsia (PE). The pathophysiology underlying obstetric mortality and morbidity in SLE is still under investigation, but several studies in recent years have suggested that placental dysfunction may play a crucial role. Understanding this association will contribute to developing therapeutic options and improving patient management thus reducing the occurrence of adverse pregnancy outcomes in this group of women. In this review, we will focus on the relationship between SLE and placental insufficiency leading to adverse pregnancy outcomes.

Adenosine diphosphate-induced aggregation is enhanced in platelets obtained from patients with thrombotic primary antiphospholipid syndrome (t-PAPS): Role of P2Y12 -cAMP signaling pathway

BACKGROUND

Thrombotic antiphospholipid syndrome (t-PAPS) is characterized by arterial, venous, or microvascular occlusions, which are explained, in part, by the presence of antiphospholipid (aPL) antibodies. Although there is much evidence indicating that isolated aPL antibodies increase the activity of platelets obtained from healthy volunteers, platelet function in t-PAPS has not been as widely studied.

OBJECTIVE

To evaluate platelet reactivity in t-PAPS patients.

METHODS

Platelet aggregation, protein expression, and cyclic nucleotide levels were carried out in platelet rich plasma (PRP) or washed platelets (WPs) obtained from t-PAPS or healthy volunteers.

RESULTS

ADP-induced aggregation was significantly higher in PRP obtained from t-PAPS than obtained from the control. The protein expression of P2Y12 receptor and Gs alpha was significantly higher and lower, respectively in WPs from t-PAPS patients. In PRP incubated with iloprost or sodium nitroprusside, the residual platelet reactivity induced by ADP was still higher in PRP from t-PAPS than from the control. Lower intracellular levels of cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) were observed in unstimulated PRP from t-PAPS patients. The protein expression of soluble guanylate cyclase subunits and phosphodiesterases types 3 and 5 did not differ. The antiplatelet activity of ticagrelor was similar between the groups and cilostazol significantly potentiated this response. Isolated aPL antibodies obtained from t-PAPS patients potentiated ADP-induced aggregation in healthy platelets but did not affect the inhibitory responses induced by iloprost or sodium nitroprusside.

CONCLUSIONS

The overexpression of P2Y12 receptor, accompanied by lower levels of cAMP and cGMP levels produced greater amplitude of ADP aggregation in platelets from t-PAPS patients.

Antigens and Antibodies of the Antiphospholipid Syndrome as New Allies in the Pathogenesis of COVID-19 Coagulopathy

High prevalence of both criteria and extra-criteria antiphospholipid antibodies (aPL) has been reported in COVID-19 patients. However, the differences in aPL prevalence decreased when an age-matched control group was included. The association of aPL with thrombotic events in COVID-19 is very heterogeneous. This could be influenced by the fact that most of the studies carried out were conducted on small populations enriched with elderly patients in which aPL was measured only at a single point and they were performed with non-standardized assays. The few studies that confirmed aPL in a second measurement showed that aPL levels hardly changed, with the exception of the lupus anticoagulant that commonly reduced. COVID-19 coagulopathy is an aPL-independent phenomenon closely associated with the onset of the disease. Thrombosis occurs later in patients with aPL presence, which is likely an additional prothrombotic factor. B2-glycoprotein deficiency (mainly aPL antigen caused both by low production and consumption) is very common during the SARS-CoV2 infection and has been associated with a greater predisposition to COVID-19 complications. This could be a new prothrombotic mechanism that may be caused by the blockage of its physiological functions, the anticoagulant state being the most important.

Long Term Follow up of Patients With Primary Obstetric Antiphospholipid Syndrome

Introduction: Primary obstetric antiphospholipid syndrome (OAPS) is defined by specific morbidities and/or losses of pregnancy in the presence of persistent antiphospholipid antibodies (aPL). This variant of APS is usually treated during pregnancy and the post-partum period. Data on occurrence of thrombotic event during long term follow-up of OAPS patients is limited.

Methods: A multi-centre retrospectively cohort of female patients with primary APS (pAPS) was assembled during 2004–2019. Patients were grouped according to disease presentation as pure OAPS or thrombotic APS (tAPS) for those presenting with thrombosis. Clinical and serological data were compared between groups.

Results: Of 219 pAPS female patients 67 (30.6%) were diagnosed with OAPS and 152 (69.4%) with tAPS. During >10 years of follow-up 24/67 (35.8%) OAPS and 71/152 (50%) tAPS suffered a new thrombotic event (p = 0.06), while obstetric morbidity was more likely in the OAPS group (31.3 vs. 10.5%, p < 0.001) respectively. Among patients with OAPS at presentation heart valve disease and the presence of ANA were related to thrombosis following diagnosis (25 vs. 4.7%, p = 0.02; and 45.8 vs. 20.8%, p = 0.04 respectively).

Conclusion: Thrombotic event following diagnosis were common among female patients with pAPS regardless of disease presentation. Heart valve disease and ANA positivity may be risk factors for thrombosis during follow-up of patients presenting with pure OAPS.

Antiphospholipid antibodies in women with recurrent embryo implantation failure: A systematic review and meta-analysis

OBJECTIVE

Antiphospholipid antibodies (aPL) are related to poor pregnancy outcomes, but their effect on embryo implantation is unclear. We aimed to assess the prevalence of different aPL in women with recurrent implantation failure (RIF).

METHODS

We searched studies in PubMed (MEDLINE), Scopus and Cochrane Library. Quality of studies was scored by the Newcastle-Ottawa Scale and risk of bias assessment by items described in RevMan5 software. Statistical analyses were made using random-effects model and presented as pooled Odds Ratio (OR), 95% confidence interval (CI). Heterogeneity was assessed by I²% and D²%.

RESULTS

This systematic review and meta-analysis included 17 studies and showed a high degree of variability in aPL positivity in RIF. In the latter, the risk of bias assessment suggested unclear bias on study performance with a median sample size and interquartile range for RIF patients and fertile women of 96 (57-417) and 100 (60.5-202.5), respectively. Among the criteria aPL, IgG anticardiolipin autoantibodies (OR 5.02, 95% CI [1.95, 12.93]) were associated with RIF. Within the non-criteria aPL, anti-β2 glycoprotein I-IgA (OR 64.8, 95% CI [9.74, 431.0]), and antiphosphatidylglycerol-IgG and IgM (OR 10.74, 95% CI [5.25, 22.0]; OR 4.26, 95% CI [1.76,10.31]; respectively) were associated with RIF, too.

CONCLUSIONS

Anticardiolipin-IgG is a prevalent autoantibody in women with RIF. Three other non-criteria aPL, aβ2GP I-IgA, aPG-IgG and aPG-IgM also present a positive rate in RIF. Overall, these results advise about testing them as indicators of RIF risk in women seeking IVF treatment.

Clinical and therapeutic value of the adjusted Global Antiphospholipid Syndrome Score in primary obstetric antiphospholipid syndrome

OBJECTIVES

(1) To assess the clinical utility of the adjusted global antiphospholipid syndrome score (aGAPSS) to predict new obstetric events during follow-up in primary obstetric antiphospholipid syndrome (POAPS) patients under standard-of-care treatment (SC) based on the use of low-dose aspirin (LDA) + heparin and (2) to study the risk of a first thrombotic event and to evaluate whether stratification according to this score could help to identify POAPS patients who would benefit from long-term thromboprophylaxis.

METHODS

This is a retrospective, multicentre study. 169 women with POAPS were evaluated for the presence of a new obstetric event and/or a first thrombotic event during follow-up [time period: 2008-2020, median: 7 years (6-12 years)]. The outcomes of 107 pregnancies from these POAPS patients with SC were studied to evaluate relapses. Simple and multivariable logistic regression analyses were performed.

RESULTS

Regarding obstetric morbidity, only triple positivity for antiphospholipid antibodies (aPLs) [OR = 8.462 (95% CI: 2.732-26.210); p < 0.0001] was found to be a strong risk factor independently associated with treatment failure. On the other hand, triple positivity for aPLs [OR=10.44 (95% CI: 2.161-50.469), p = 0.004] and an aGAPSS ≥7 [OR = 1.621 (95% CI: 1.198-2.193), p = 0.002] were independent risk factors associated with a first thrombotic event. LDA was marginally associated with a decrease in the risk of thrombosis only in patients with aGAPSS ≥ 7 (p = 0.048).

CONCLUSION

aGAPSS appears to be useful in predicting the occurrence of a first thrombotic event in POAPS patients, and these stratification of patients could be helpful in selecting patients who would benefit from thromboprophylaxis with LDA.

Drug-induced antiphospholipid syndrome: Analysis of from the WHO international database

OBJECTIVE

As with drug-induced lupus, some drugs may induce an antiphospholipid syndrome (APS). With the always growing numbers of new molecules, the list of the liable treatments evolves rapidly. We herein analyzed VigiBase, the international pharmacovigilance database, to identify drugs suspected of inducing APS.

METHODS

All the reported cases associated with "anti-phospholipid syndrome" using the preferred term level of medDRA (dictionary of regulated drug activity) when associated with anti-phospholipid antibodies in VigiBase were analyzed. For each treatment, a Bayesian disproportionality indicator (i.e. information component, IC) was calculated. A drug was significantly associated with APS if the 95% lower-end of the IC credibility interval was positive (IC₀₂₅ > 0). Drugs with potential protopathic bias were excluded.

RESULTS

From 01/11/2000 to 25/07/2021, 790 reports of suspected drug-induced APS were found in VigiBase. After excluding drugs reported by a single country and drugs with protopathic bias, fourteen drugs (n = 359 reports) were associated with APS with an IC_{0 25} > 0. These drugs were hormons: ethinylestradiol-etonogestrel and drospirenone-ethynilestradiol; platelet growth factors: eltrombopag, romiplostim; vaccines: Human Papillomavirus vaccine, hepatitis A and B vaccines and typhoid vaccine; antibiotics: minocycline; nonstreroidal anti-inflammatory: rofecoxib; biotherapy: interferon beta-1-a, etanercept; anti-hypertensive drug: hydralazine; bisphosphonates: alendronic acid and antipsychotic: olanzapine. The mean age at diagnosis of drug-induced APS was 39.2 years [29.3;47.9] and there were 63.5% of female patients. The mean delay from first exposition to drug-induced APS was 19.7 months [4.5; 38.8]. Drug-induced APS was reported as a severe side effect in 66.3% of cases: 8.4% with a life-threatening event and 2.5% of death (n = 9). A third (n = 118, 32.9%) pulmonary embolism events were reported and 4.2% (15) cerebral infarctions. 14.8% (53) cases were associated with a systemic lupus, a sub-analysis without lupus cases showed the same severity of cases.

CONCLUSION

This study identified 14 drugs potentially associated with drug-induced APS that may prove useful in the investigational work-up in any new diagnosis of APS.

TRIAL REGISTRATION NUMBER

NCT03994302.

Clinical Management of Thrombotic Antiphospholipid Syndrome

Thrombotic manifestations of antiphospholipid syndrome are often a therapeutic dilemma and challenge. Despite our increasing knowledge of this relatively new disease, many issues remain widely unknown and controversial. In this review, we summarise the latest literature and guidelines on the management of thrombotic antiphospholipid syndrome. These include the laboratory assays involved in antiphospholipid antibodies (aPL) testing, the use of direct oral anticoagulants in secondary prevention, management of recurrent thrombosis, individuals with isolated aPL, and catastrophic antiphospholipid syndrome. Treatment aims to prevent the potentially fatal and often disabling complications of APS with antithrombotic and cardiovascular risks prevention strategies. Some insights and updates on topical issues in APS are provided. We also include our current practice, which we believe is the pragmatic approach based on the currently available evidence.

Antiphospholipid antibodies increase endometrial stromal cell decidualization, senescence and inflammation via TLR4, ROS and p38 MAP kinase signaling

OBJECTIVE

Miscarriage affects one in seven pregnancies and antiphospholipid autoantibodies (aPL) are one of the biggest risk factors for recurrent pregnancy loss. While aPL target the endometrial stroma, little is known about their impact. Endometrial stromal cells (EnSCs) undergo decidualization each menstrual cycle, priming the uterus to receive implanting embryos. Thus, appropriate decidualization and EnSC function is key for establishment of a successful pregnancy.

METHODS

EnSCs under decidualizing conditions were exposed to aPL or control IgG alone or in the presence of either a Toll-like receptor 4 (TLR4) antagonist, a p38 MAPK inhibitor, a reactive oxygen species (ROS) inhibitor, low-molecular weight heparin (LMWH), or acetyl salicylic acid (ASA). Secretion of decidualization markers and inflammatory interleukin (IL)-8 were quantified by ELISA, and senescence-associated β-galactosidase activity was evaluated. In a mouse model of decidualization, aPL or control IgG was administered and uterine expression of decidualization and inflammatory markers quantified by RT-qPCR.

RESULTS

aPL increased human EnSC decidualization, senescence and inflammation. This phenotype was recapitulated in the mouse model. The decidualization and inflammatory responses were partially mediated by TLR4 and p38 MAP kinase, while the decidualization and senescence responses were ROS-dependent. LMWH, commonly used to treat aPL-positive women at risk for obstetric complications, reduced the ability of aPL to increase EnSC decidualization and inflammation.

CONCLUSION

These findings shed new light on the pathogenesis of pregnancy complications in women with aPL and underscore the benefit of heparin for preventing pregnancy loss in this high-risk population.

Reproductive Issues and Pregnancy Implications in Systemic Sclerosis

Systemic sclerosis (SSc) is a rare systemic autoimmune disease that can influence reproductive health. SSc has a strong female predominance, and the disease onset can occur during fertility age in almost 50% of patients. Preconception counseling, adjustment of treatment, and close surveillance during pregnancy by a multidisciplinary team, are key points to minimize fetal and maternal risks and favor successful pregnancy outcomes. The rates of spontaneous pregnancy losses are comparable to those of the general obstetric population, except for patients with diffuse cutaneous SSc and severe internal organ involvement who may carry a higher risk of abortion. Preterm birth can frequently occur in women with SSc, as it happens in other rheumatic diseases. Overall disease activity generally remains stable during pregnancy, but particular attention should be paid to women with major organ disease, such as renal and cardiopulmonary involvement. Women with such severe involvement should be thoroughly informed about the risks during pregnancy and possibly discouraged from getting pregnant. A high frequency of sexual dysfunction has been described among SSc patients, both in females and in males, and pathogenic mechanisms of SSc may play a fundamental role in determining this impairment. Fertility is overall normal in SSc women, while no studies in the literature have investigated fertility in SSc male patients. Nevertheless, some considerations regarding the impact of some immunosuppressive drugs should be done with male patients, referring to the knowledge gained in other rheumatic diseases.

Detection of IgA Antiphospholipid Antibodies Does not Improve Thrombotic Antiphospholipid Syndrome Classification: A two-Center Study

Background

Thrombotic antiphospholipid syndrome (APS) is a systemic autoimmune disease; its diagnosis requires meeting both clinical and laboratory criteria. Prevalence rates of immunoglobulin (Ig) A anticardiolipin antibodies (aCL) and IgA anti-β₂ glycoprotein I antibodies (aβ₂GPI) remain unknown, and the clinical value of these antibodies to APS classification remains controversial. Therefore, we aimed to examine both items in the Chinese population.

Methods

Using chemiluminescence immunoassay, antiphospholipid antibodies (aPL) were quantified in 12,582 hospital-based general population, 278 thrombotic APS patients, and 233 healthy controls.

Results

In the general population, the positive rates of IgA aCL and IgA aβ₂GPI antibodies were 2.87% and 1.99%, respectively. Furthermore, isolated IgA aPL-positivity rate was 0.72% in patients with APS, which was comparable to those in the general population (0.68%, p = 1) and in healthy controls (0.43%, p = 1). Among the IgA aPL-positive individuals in the general population, isolated IgA-positive individuals had lower serum levels of IgA antibodies (p = 0.007 for IgA aCL and p = 0.059 for IgA aβ₂GPI). Regarding to APS classification, adding IgA aPL into conventional aPL assays may not improve and may even deteriorate the net reclassification index for APS; besides, no association between thrombosis and IgA aPL was observed.

Conclusions

this study assessed the prevalence of various aPL in Chinese population. IgA aPL may not enhance the classification ability of established laboratory criteria for thrombotic APS. Our data do not support the addition of IgA aPL to conventional aPL assays.

Antiphospholipid antibody-induced trophoblast responses are differentially modulated by viral dsRNA and viral ssRNA

PROBLEM

Women with antiphospholipid antibodies (aPL) are at increased risk for pregnancy loss and preeclampsia. aPL target the trophoblast and induce a pro-inflammatory, anti-angiogenic and anti-migratory profile. Since infection during pregnancy can increase the risk for preeclampsia, a viral infection could further increase this in women with aPL. The goal of this study was to characterize the effect of viral components on trophoblast responses to aPL.

METHOD OF STUDY

A human first trimester trophoblast cell line was treated with or without aPL or control IgG in the presence of media, viral dsRNA or viral ssRNA. Supernatants were measured for inflammatory IL-1β and IL-8; inflammasome-associated uric acid and caspase-1 activity; and anti-angiogenic sFlt-1. Trophoblast migration was measured using a two-chamber assay.

RESULTS

Viral dsRNA augmented aPL-induced trophoblast caspase-1 activity, and IL-1β and IL-8 secretion in an additive manner. Viral ssRNA inhibited aPL-induced uric acid, IL-1β and sFlt-1 secretion, and further exacerbated aPL-inhibition of trophoblast migration.

CONCLUSION

While viral ssRNA may have some protective effects on aPL-induced inflammation and anti-angiogenic responses, viral dsRNA exacerbated aPL-mediated inflammation and viral ssRNA further limited cell migration, which could prove detrimental to placentation. Thus, viral infections may contribute to adverse pregnancy outcomes in women with aPL.

Pathophysiology of the Antiphospholipid Antibody Syndrome

The antiphospholipid syndrome is characterized by antibodies directed against phospholipid-binding proteins and phospholipids attached to cell membrane receptors, mitochondria, oxidized lipoproteins, and activated complement components. When antibodies bind to these complex antigens, cells are activated and the coagulation and complement cascades are triggered, culminating in thrombotic events and pregnancy morbidity that further define the syndrome. The phospholipid-binding proteins most often involved are annexins II and V, β2-glycoprotein I, prothrombin, and cardiolipin. A distinguishing feature of the antiphospholipid syndrome is the "lupus anticoagulant". This is not a single entity but rather a family of antibodies directed against complex antigens consisting of β2-glycoprotein I and/or prothrombin bound to an anionic phospholipid. Although these antibodies prolong in vitro clotting times by competing with clotting factors for phospholipid binding sites, they are not associated with clinical bleeding. Rather, they are thrombogenic because they augment thrombin production in vivo by concentrating prothrombin on phospholipid surfaces. Other antiphospholipid antibodies decrease the clot-inhibitory properties of the endothelium and enhance platelet adherence and aggregation. Some are atherogenic because they increase lipid peroxidation by reducing paraoxonase activity, and others impair fetal nutrition by diminishing placental antithrombotic and fibrinolytic activity. This plethora of destructive autoantibodies is currently managed with immunomodulatory agents, but new approaches to treatment might include vaccines against specific autoantigens, blocking the antibodies generated by exposure to cytoplasmic DNA, and selective targeting of aberrant B-cells to reduce or eliminate autoantibody production.

Low molecular weight heparin or LMWH plus aspirin in the treatment of unexplained recurrent miscarriage with negative antiphospholipid antibodies: A meta-analysis of randomized controlled trial

OBJECTIVE

Unexplained recurrent miscarriage (uRM) has caused serious distress to women of childbearing age, and effective treatment is particularly important. The aim of this meta-analysis is to compare the efficacy of low molecular weight heparin (LMWH) and LMWH combined with aspirin for uRM.

METHODS

Databases including PubMed, Web of Science, Embase, Scopus and the Cochrane Library databases were electronically searched to identify randomized controlled trials that reported the LMWH or LMWH combined with aspirin for women with uRM and negative antiphospholipid antibodies (aPL). The retrieval time is limited from inception to June 2021. Two reviewers independently screened literature, extracted data, and assessed risk bias of included studies. Meta-analysis was performed by using STATA 12.0 software.

RESULTS

A total of 7 studies involving 1849 patients were included. The meta-analysis results showed that compared with the control group, both LMWH and LMWH + aspirin interventions showed no substantial influence on miscarriage rate (LMWH: RR = 0.69, 95%CI: 0.34-1.39, P = 0.293, LMWH + aspirin: RR = 0.62, 95%CI: 0.30-1.27, P = 0.19) and the occurrence of pre-eclampsia (LMWH: RR = 1.1, 95%CI: 0.53-2.31, P = 0.792; LMWH + aspirin: RR = 1.49, 95%CI: 0.25-8.79, P = 0.662). LMWH therapy had no influence on the live births (RR = 0.99, 95%CI: 0.92-1.06, P = 0.72). Subgroup analysis showed that enoxaparin is not effective in women with uRM and negative aPL (miscarriage rate: RR = 0.82, 95%CI: 0.31-2.19, P = 0.695; pre-eclampsia: RR = 1.03, 95%CI: 0.46-2.33, P = 0.936).

CONCLUSIONS

LMWH and LMWH combined with aspirin therapy cannot improve the pregnancy outcome of women with uRM and negative aPL. However, the above conclusions are still required to be verified through more RCTs due to the limited quantity of included studies.

Effects of anti-beta 2-glycoprotein 1 antibodies and its association with pregnancy-related morbidity in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by venous, arterial, or small-vessel thrombosis and/or pregnancy-related morbidity, associated with persistent positivity of antiphospholipid antibodies (aPL). Pregnancy-related morbidity in APS patients is characterized by unexplained fetal deaths, premature birth of morphologically normal newborns, and/or consecutive pregnancy losses before the 10^th week of gestation. Beta 2-glycoprotein 1 (ß2GP1) is the main antigen recognized by aPL and plays an essential role in the pathogenesis of APS. Antibodies against ß2GP1 (aß2GP1) are involved in damage-generating mechanisms in APS due to their interaction with trophoblasts, decidua, and endothelial cells. aß2GP1 might be used as a prognostic tool for obstetric risk stratification and ß2GP1 could be a target for molecular-targeted treatment to prevent pregnancy morbidity in APS. This review describes these aspects of aß2GP1, including effects on different cellular targets, its association with the severity of obstetric manifestations and the potential of ß2GP1-targeted therapies for APS.

Proteomics and enriched biological processes in Antiphospholipid syndrome: A systematic review

Identification of differentially expressed proteins in antiphospholipid syndrome (APS) is a developing area of research for unique profiles of this pathology. Advances in technologies of mass spectrometry brings improvements in proteomics and results in assessment of soluble or cellular proteins which could be candidates for clinical biomarkers of primary APS. The use of blood as a source of proteins ease the acquisition of samples for proteomics analyses and later for disease diagnosis. We performed a systematic review to explore the proteomics studies carried out in circulating released proteins (serum, plasma) or cellular proteins (monocytes and platelets) of APS patients. The study groups differentiate among clinical APS cases with the aim to translate molecular findings to disease stratification and to improve APS diagnosis and prognosis. These studies also include the unravelling of new autoantibodies in non-criteria APS or how post-translational protein modifications provides clues about the pathological mechanisms of antigen-autoantibody recognition. Herein, we identified 82 proteins that were dysregulated in APS across eleven studies. Enrichment analysis revealed its connection to cellular activation and degranulation that eventually leads to thrombosis as the main biological process highlighted by these studies. Validation of APS-relevant proteins by functional and mechanistic studies will be essential for patient stratification and the development of targeted therapies for every clinical subtype of APS.

Distinct features of youth-onset primary antiphospholipid syndrome

BACKGROUND

Characteristics of primary APS (PAPS) in the youth population have never been studied. In contrast with children, pregnancy is genuinely relevant in the youth age, and understanding clinical characteristics of PAPS patients within this specific age stratum may also provide insights regarding the well-known risk of poor obstetric outcomes during the adolescence.

OBJECTIVE

To evaluate clinical and laboratory characteristics of patients with youth-onset PAPS (15-24 years) and compare them with adult-onset PAPS (over 24 years old).

METHODS

This was a cross-sectional study derived from two rheumatology outpatient clinics. Patients who fulfilled Sidney criteria and who were 15 years of age or older at disease onset were included. Secondary APS patients were excluded. We subdivided patients into two groups: youth- (15-24 years) and adult-onset (over 24 years) and compared them regarding demographic characteristics, criteria and non-criteria manifestations, cardiovascular risk factors, and aPL status. For the pregnancy outcomes analysis, ever-pregnant patients were divided in three groups: youth-onset, early adult-onset (25-34 years), and late adult-onset (35-49 years).

RESULTS

A total of 250 consecutive PAPS patients were included. Groups had a comparable female and Caucasian distribution. We found a similar disease duration (14.0±7.9 vs 17.0±10.1 years, p = 0.079) and similar rates of thrombotic arterial (34.2% vs. 42.0%, p = 0.250) and venous events (69.7% vs. 69.5%, p = 0.975) between them. Skin ulcers were more frequent in the youth-onset group (17.1% vs. 4.0%, p = 0.001), whereas nephropathy was less common (1.3% vs. 8.0%, p = 0.039). No differences were observed for the other criteria and non-criteria manifestations. The adult-onset group presented more frequently with hypertension (p = 0.002), hyperlipidemia (p = 0.008), and smoking (p = 0.003). The youth-onset group presented a higher frequency of obstetric events as the first manifestation of PAPS (30.3% vs. 21.7%, p = 0.005), with worse pregnancy outcomes, namely, fetal death (58.5% vs. 46.4% vs. 24.1%, p = 0.012) and premature delivery (35.8% vs. 19.0% vs. 10.3%, p = 0.016). Of note, all groups had a comparable number of pregnancies (2.81±2.52 vs 2.74±2.07, p = 0.899).

CONCLUSION

This study provides novel evidence that youth-onset PAPS presents a higher frequency of obstetric complications as its first manifestation, with an increased risk of fetal death and preterm delivery. Early recognition of this condition by obstetricians is essential to improve prognosis.

Antiphospholipid Antibody Assays in 2021: Looking for a Predictive Value in Addition to a Diagnostic One

Antiphospholipid antibodies (aPL) are mandatory for the diagnosis but are also a risk factor for the antiphospholipid syndrome (APS) clinical manifestations. Lupus anticoagulant (LA), anticardiolipin (aCL), and anti-beta2 glycoprotein I (β₂GPI) assays are the formal laboratory classification/diagnostic criteria. Additional nonclassification assays have been suggested; among them, antiphosphatidylserine-prothrombin (aPS/PT) and antidomain 1 β₂GPI antibodies are the most promising ones although not yet formally accepted. aPL represent the example of a laboratory test that moved from dichotomous to quantitative results consistent with the idea that reporting quantitative data offers more diagnostic/prognostic information for both vascular and obstetric manifestations. Although the general rule is that the higher the aPL titer, the higher the test likelihood ratio, there is growing evidence that this is not the case for persistent low titers and obstetric events. LA displays the highest diagnostic/prognostic power, although some isolated LAs are apparently not associated with APS manifestations. Moreover, isotype characterization is also critical since IgG aPL are more diagnostic/prognostic than IgA or IgM. aPL are directed against two main autoantigens: β₂GPI and PT. However, anti-β₂GPI antibodies are more associated with the APS clinical spectrum. In addition, there is evidence that anti-β₂GPI domain 1 antibodies display a stronger diagnostic/prognostic value. This finding supports the view that antigen and even epitope characterization represents a further step for improving the assay value. The strategy to improve aPL laboratory characterization is a lesson that can be translated to other autoantibody assays in order to improve our diagnostic and prognostic power.

Biochemical and clinical predictors in pregnant women with antiphospholipid syndrome and systemic lupus erythematosus: comprehensive update

BACKGROUND

Autoimmune diseases as antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE) could cause many maternal complications. The most common maternal complications of autoimmune diseases are lupus flare, hypertension, nephritis, preeclampsia (PE), eclampsia, and poor pregnancy outcomes which including preterm delivery and pregnancy loss. Only the lupus anticoagulant in the greatest prospective multicenter study has been associated with adverse pregnancy outcomes of the APS.

PURPOSE

This review aims to provide a comprehensive update for predictors in pregnant women with APS/SLE.

METHODS

These data have been collected from clinical and pathological studies, systematic reviews, and meta-analysis.

RESULTS

In recent years the SLE and APS demonstrated to have different and valuable clinical and biomarker predictors for the pregnancy outcome. Treatment of pregnant women with APS is low molecular weight heparin (LMWH) and aspirin; however, around 75% of this management is considered successful.

CONCLUSION

This review summarizes recent research that focuses on biochemical and clinical predictors of adverse pregnancy outcomes (APOs) of pregnant women with SLE and APS. Furthermore, we have collected more evidence that confirms the safety and efficacy of hydroxychloroquine (HCQ) preventing APOs.

β2 glycoprotein I participates in phagocytosis of apoptotic neurons and in vascular injury in experimental brain stroke

Beta-2 Glycoprotein I (β2-GPI) is the main target of anti-phospholipid antibodies (aPL) in the autoimmune anti-phospholipid syndrome, characterized by increased risk of stroke. We here investigated the antibody independent role of β2-GPI after ischemia/reperfusion, modeled in vivo by transient middle cerebral artery occlusion (tMCAo) in male C57Bl/6J mice; in vitro by subjecting immortalized human brain microvascular endothelial cells (ihBMEC) to 16 h hypoxia and 4 h re-oxygenation. ApoH (coding for β2-GPI) was upregulated selectively in the liver at 48 h after tMCAo. At the same time β2-GPI circulating levels increased. β2-GPI was detectable in brain parenchyma and endothelium at all time points after tMCAo. Parenchymal β2-GPI recognized apoptotic neurons (positive for annexin V, C3 and TUNEL) cleared by CD68+ brain macrophages. Hypoxic ihBMEC showed increased release of IL-6, over-expression of thrombomodulin and IL-1α after re-oxygenation with β2-GPI alone. β2-GPI interacted with mannose-binding lectin in mouse plasma and ihBMEC medium, potentially involved in formation of thrombi. We show for the first time that brain ischemia triggers the hepatic production of β2-GPI. β2-GPI is present in the ischemic endothelium, enhancing vascular inflammation, and extravasates binding stressed neurons before their clearance by phagocytosis. Thus β2-GPI may be a new mediator of brain injury following ischemic stroke.

Anticardiolipin Positivity Is Highly Associated With Intrauterine Growth Restriction in Women With Antiphospholipid Syndrome

The purpose of our study was to evaluate pregnancy outcomes of women with antiphospholipid antibodies (aPL) positivity and assess risk factors associated with adverse pregnancy outcomes. Pregnant women with aPL positivity were enrolled prospectively in China from January 2017 to March 2020. Treatment of low-dose aspirin and low molecular weight heparin were given. Pregnancy outcomes and coagulation function were recorded and compared with normal pregnancies. Multivariable logistic regression was performed to identify risk factors associated to intrauterine growth restriction (IUGR). 270 pregnant women, including 44 diagnosed as Antiphospholipid syndrome (APS), 91 as non-criteria APS (NCAPS) and 135 normal cases as control, were enrolled in the study. The live birth rate in aPL carriers and APS group was 97% and 95.5%, respectively. Adverse pregnancy outcomes did not show significant difference between aPL carriers and normal pregnancies, and between APS and NCAPS, except for IUGR. The incidence of IUGR was significantly higher in aPL carriers than normal pregnancies, and in APS patients than NCAPS (P < 0.05). After controlling for age, in vitro fertilization (IVF), pregnancy losses related to APS and treatment, anticardiolipin (aCL) positivity was the only variable significantly associated with IUGR, with an adjusted odds ratio of 4.601 (95% CI, 1.205-17.573). Better pregnant outcomes of aPL positive women, include APS and NCAPS, were achieved in our study with treatment based on low-dose aspirin (LDA) plus low molecular weight heparin (LMWH). The incidence of IUGR was still higher in them, and aCL positivity was the only one risk factor associated with IUGR.

Inflammatory markers in thrombosis associated with primary antiphospholipid syndrome

The role of inflammation in thrombotic complications of primary antiphospholipid syndrome (PAPS) is controversial. The aim of this study was to evaluate levels of inflammation and coagulation markers in patients with thrombotic PAPS (t-PAPS). Patients with t-PAPS and individuals with no history of thrombosis were enrolled. The association of t-PAPS with levels of tumor necrosis factor (TNF)-α, C-reactive protein (hs-CRP), interferon (IFN)-α, interleukins (IL)-6, -8, factor VIII (FVIII), von Willebrand factor (VWF) and tissue factor (TF) was evaluated by regression models. The levels of these markers were also compared between controls and subgroups of t-PAPS patients with triple positivity, recently diagnosed thrombosis, recurrent thrombosis and venous thrombosis. Patients with t-PAPS (n = 101) had a 8.6-fold increased levels of TNF-α, 90% increased levels of hs-CRP, 80% increased levels of IL-6, 30% increased levels of FVIIIAg, 50% increased levels of VWF and 66% increased levels of TF as compared to controls (n = 131), and the differences did not change after adjustments for sex, age and cardiovascular risk factors. Inflammatory markers were elevated in t-PAPS regardless of the aPL profile, number of previous thrombosis or time elapsed since diagnosis. TNF-α and IL-8 levels were higher in t-PAPS patients with venous thrombosis, in comparison with those with arterial thrombosis and controls. Patients with t-PAPS presented with increased levels of inflammatory and coagulation markers, which suggests that t-PAPS is associated not only with hypercoagulability but also with a persistent inflammatory state.

Pregnancy outcome predictors in antiphospholipid syndrome: A systematic review and meta-analysis

OBJECTIVE

To identify and assess the magnitude of effect of pregnancy outcome predictors in women with antiphospholipid syndrome (APS) by means of systematic review and meta-analysis.

METHODS

PubMed and Embase were searched (13th June 2020) for studies reporting on pre-pregnancy risk factors of pregnancy outcomes in APS patients. Literature screening and data extraction were conducted by two reviewers independently, in a blinded standardized manner. Pooled univariate odds ratios (OR) were computed using a random effects model. Heterogeneity was assessed by I²%.

RESULTS

The search yielded 3013 unique results; 27 records were included in this meta-analysis. Previous thrombosis was associated with a decreased live birth risk (OR 0.60, p < 0.01, I² = 40%), increased neonatal mortality (OR 15.19, p < 0.01, I² = 0%), an increased risk of antenatal or postpartum thrombosis (OR 6.26, p < 0.01, I² = 0%) and an increased risk of delivering a small for gestational age neonate (SGA) (OR 2.60, p = 0.01, I² = 0%). Patients with an APS laboratory category I (double or triple positivity) profile had a decreased live birth risk (OR 0.66, p < 0.01, I² = 0%), an increased risk of SGA (OR 1.86, p = 0.01, I² = 43%) and preterm birth (OR 1.35, p < 0.01, I² = 49%). Triple positivity was associated with a decreased live birth risk (OR 0.33, p < 0.01, I² = 68%), an increased risk of preeclampsia (OR 2.43, p = 0.02, I² = 35%) and SGA (OR 2.47, p = 0.04, I² = 61%). Patients with lupus anticoagulant positivity had an increased risk of preeclampsia (OR 2.10, p = 0.02, I² = 48%), SGA (OR 1.78, p < 0.01, I² = 0%) and preterm birth (OR 3.56, p = 0.01, I² = 48%). Risk of bias assessment suggested considerable bias on study participation and statistical methods.

CONCLUSIONS

The results of this meta-analysis identified previous thrombosis, laboratory category I, triple positivity and lupus anticoagulant positivity as the most important predictors of adverse pregnancy outcomes. This up-to-date knowledge, can be used in preconception counseling and tailoring of obstetric care.

Immunological and physiopathological approach of COVID-19 in pregnancy

Coronavirus disease-2019 (COVID-19) related to Coronavirus-2 (SARS-CoV-2) is a worldwide health concern. Despite the majority of patients will evolve asymptomatic or mild-moderate upper respiratory tract infections, 20% will develop severe disease. Based on current pathogenetic knowledge, a severe COVID-19 form is mainly a hyperinflammatory, immune-mediated disorder, triggered by a viral infection. Due to their particular immunological features, pregnant women are supposed to be particularly susceptible to complicate by intracellular infections as well as immunological disturbances. As an example, immune-thrombosis has been identified as a common immune-mediated and pathogenic phenomenon both in COVID-19, in obstetric diseases and in COVID-19 pregnant women. According to extensive published clinical data, is rationale to expect an interference with the normal development of pregnancy in selected SARS-CoV-2-infected cases, mainly during third trimester.This manuscript provides insights of research to elucidate the potential harmful responses to SARS-CoV-2 and /or other coronavirus infections, as well as bidirectional interactions between COVID-19 and pregnancy to improve their respective management.

EUREKA algorithm predicts obstetric risk and response to treatment in women with different subsets of anti-phospholipid antibodies

OBJECTIVES

aPL, the serum biomarkers of APS, are the most common acquired causes of pregnancy morbidity (PM). This study investigates the impact of aPL positivity fulfilling classification criteria ('criteria aPL') and at titres lower than thresholds considered by classification criteria ('low-titre aPL') on PM and assesses the effectiveness of low-dose aspirin (LDASA), low molecular weight heparin (LMWH) and HCQ in reducing the probability of PM (PPM).

METHODS

Longitudinal data on 847 pregnancies in 155 women with persistent aPL at any titre and 226 women with autoimmune diseases and negative aPL were retrospectively collected. A generalized estimating equations model for repeated measures was applied to quantify PPM under different clinical situations.

RESULTS

EUREKA is a novel algorithm that accurately predicts the risk of aPL-associated PM by considering aPL titres and profiles. aPL significantly impact PPM when at low titres and when fulfilling classification criteria. PPM was further stratified upon the aPL tests: aCL IgG/IgM and anti-β2-glycoprotein I (β2GPI) IgM, alone or combined, do not affect the basal risks of PPM, an increase occurs in case of positive LA or anti-β2GPI IgG. LDASA significantly affects PPM exclusively in women with low-titre aPL without anti-β2GPI IgG. The LDASA + LMWH combination significantly reduces PPM in all women with low-titre aPL and women with criteria aPL, except those carrying LA and anti-β2GPI IgG. In this group, the addition of HCQ further reduces PPM, although not significantly.

CONCLUSION

EUREKA allows a tailored therapeutic approach, impacting everyday clinical management of aPL-positive pregnant women.

Effect of hydroxychloroquine on antiphospholipid antibodies-inhibited endometrial angiogenesis

BACKGROUND

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombotic events and/or pregnancy morbidity (≥3 recurrent early miscarriage or fetal death or a prematurity <34 weeks of gestation) with persistently positive antiphospholipid antibodies (aPLs). It is reported that aPLs damage the placental tissue by binding to β2-glycoprotein I (β2GPI) on the surface of trophoblast and endothelial cells. Hydroxychloroquine (HCQ) is considered to be beneficial in the treatment of obstetrical APS and shown to restore the aPL-inhibited invasion and differentiation of trophoblast. However, not enough evidence exists regarding the effect of HCQ on endometrial angiogenesis. The aim of our study was to assess whether HCQ has an effect on aPL-inhibited endothelial angiogenesis.

METHODS

In this research, to explore the effect of HCQ for angiogenesis, we investigated: (1) Human umbilical vein endothelial cells (HUVECs) viability by CCK-8; (2) HUVECs migration by wound healing; (3) HUVEC angiogenesis by Matrigel assay in vitro; (4) mRNA expression of MMP-2 and VEGF by real-time quantitative Polymerase Chain Reaction (RT-PCR); (5) protein expression of VEGF, MMP-2 by western blot.

RESULTS

We found that HCQ treatment significantly restored the expression of aPL-inhibited VEGF and MMP-2. HCQ restored aPL-inhibited HUVEC proliferation, migration, and angiogenesis in vitro.

CONCLUSION

In conclusion, aPLs inhibit HUVECs angiogenesis, however, HCQ can restore the effect of aPL-inhibited HUVECs migration and angiogenesis in vitro, demonstrating its beneficial therapeutic role in obstetrical APS.

Maternal and foetal placental vascular malperfusion in pregnancies with anti-phospholipid antibodies

OBJECTIVE

The objective of the study was to evaluate the rates of pathological placental lesions among pregnant subjects positive for aPL antibodies.

METHODS

We performed a longitudinal case-control study including 27 subjects with primary APS, 51 with non-criteria APS, 24 with aPL antibodies associated with other well-known CTDs enrolled at the end of the first trimester of pregnancy and 107 healthy controls.

RESULTS

Compared with controls and after correction for multiple comparisons, primary, non-criteria APS and aPL associated to CTD, subjects had lower placental weight, volume and area. After penalized logistic regression analysis to correct for potential confounders, placental lesions suggesting severe maternal vascular malperfusion (MVM) were more common among primary [odds ratio (OR) 11.7 (95% CI 1.3, 108)] and non-criteria APS [OR 8.5 (95% CI 1.6, 45.9)] compared with controls. The risk of foetal vascular malperfusion (FVM) was higher in primary APS [OR 4.5 (95% CI 1.2, 16.4)], aPL associated with CTDs [OR 3.1 (95% CI 1.5, 6.7)] and non-criteria APS [OR 5.9 (95% CI 1.7, 20.1)] compared with controls. Among clinical and laboratory criteria of APS, first trimester aCL IgG >40 UI/ml [OR 4.4 (95% CI 1.3, 14.4)], LA positivity [OR 6.5 (95% CI 1.3, 33.3)] and a history of pre-eclampsia at <34 weeks [OR 32.4 (95% CI 6.5, 161)] were the best independent first trimester predictors of severe MVM [area under the curve 0.74 (95% CI 0.6, 0.87)].

CONCLUSION

Compared with healthy controls, pregnant subjects with aPL antibodies have an increased risk of placental lesions, suggesting MVM and FVM. First-trimester variables such as aCL IgG >40 UI/ml and a history of pre-eclampsia were significant predictors of both severe MVM and FVM.

Clinical characteristics and prognosis of patients with isolated thrombotic vs. obstetric antiphospholipid syndrome: a prospective cohort study

BACKGROUND

Several studies suggested that thrombotic and obstetric antiphospholipid syndromes could be independent identities, but few have systematically compared their clinical characteristics and prognosis.

OBJECTIVE

The objective of this study is to identify key differences between thrombotic APS (tAPS) and obstetric APS (oAPS).

METHODS

This single-center, prospective study included consecutive patients with primary antiphospholipid syndrome (APS) receiving treatment at the Peking Union Medical College Hospital during a period from 2013 to 2020.

RESULTS

Screening of the database yielded a total of 244 women with positive antiphospholipid antibody (aPL). Among the 105 women with primary APS, 39 (37.14%) had isolated tAPS (ItAPS), 44 (41.90%) had isolated oAPS (IoAPS), and 9 (8.57%) had both tAPS and tAPS+oAPS. In comparison to those with IoAPS, patients with ItAPS had older age (41.92 ± 11.97 vs. 33.16 ± 4.22 years, P < 0.01), higher rate of cardiovascular risk (at least one positive of coronary heart disease, hypertension, obesity, diabetes, and hyperlipidemia) (41.03% vs. 6.82%, P < 0.01), and higher frequency of thrombocytopenia (43.59% vs. 20.45%, P < 0.05). Antibody profiles were generally similar among the groups, but isolated anti-β2GPI positivity was more common in patients with IoAPS (52.27% vs. 17.94% for ItAPS, P = 0.01). Triple aPL positivity was more common in patients with both tAPS and oAPS (66.67% vs. 46.15% for ItAPS vs. 25% for IoAPS, P = 0.022). Blood homocysteine was higher in patients with ItAPS (11.20 vs. 9.90 μmol/L for IoAPS, P < 0.05), but there were no differences in inflammatory markers or complements. Recurrence rate of thrombosis was higher in patients with ItAPS (33.33% vs. 2.27% for IoAPS, P ≤ 0.001) with a mean follow-up of 61 months.

CONCLUSION

Despite generally similar antibody and biochemical profiles, patients with ItAPS had much higher risk of recurrent thrombosis than IoAPS, supporting distinct mechanisms of pathogenesis.