Thrombocytopenia as a thrombotic risk factor in patients with antiphospholipid antibodies without disease criteria

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.

The presence of non-criteria manifestations negatively affects the prognosis of seronegative antiphospholipid syndrome patients: a multicenter study

Background

Seronegative antiphospholipid syndrome (SN-APS) is often defined as the presence of APS criteria manifestations, negative antiphospholipid antibodies (aPL), and coexistence of APS non-criteria manifestations. Nevertheless, the impact of these non-criteria features is still unclear. On a different note, the relevance of one single aPL positive determination in patients with APS manifestations is another domain with limited evidence. We aim to compare the course of SN-APS and single-positive aPL (SP-aPL) patients with that of individuals with APS manifestations without non-criteria features/aPL positivity (controls).

Methods

Retrospective analysis of patients with thrombosis/obstetric morbidity assessed in two European hospitals between 2005 and 2020. Patients were divided into SN-APS, SP-aPL, and control groups. Clinical characteristics, comorbidities, and therapies were compared.

Results

A total of 82 patients were included in the SN-APS group, 88 in the SP-aPL group, and 185 in the control group. In Cox regression model, SN-APS displayed more thrombosis recurrence than controls (HR 3.8, 95% CI 2.2–6.5, p < 0.001) even when adjusting for the presence of hereditary thrombophilia, systemic lupus erythematosus, or contraceptive hormonal treatment. In SP-aPL, the difference in thrombosis recurrence did not reach statistical significance (p = 0.078). Indefinite anticoagulation (p < 0.001 and p = 0.008, respectively) and vitamin K antagonist (VKA) use (p < 0.001 in both cases) were more common in SN-APS/SP-aPL.

Conclusion

SN-APS displayed more thrombosis recurrence, indefinite anticoagulation, and VKA use than controls without non-criteria manifestations. The presence of such features in patients with thrombosis and negative aPL may negatively impact their clinical course.

Risk Factors for the Development of the Disease in Antiphospholipid Antibodies Carriers: A Long-term Follow-up Study

The natural history of antiphospholipid antibodies (aPL) carriers is not well-established. The objectives of the present study were (a) to study the probability of developing clinical criteria of antiphospholipid syndrome (APS), (b) to identify potential risk factors for developing thrombosis and/or obstetric complications, (c) to study the association between the antibody profile and development of APS, and (d) to determine the efficacy of primary prophylaxis. We retrospectively analyzed 138 subjects with positive aPL who did not fulfill clinical criteria for APS. The mean follow-up time was 138 ± 63.0 months. Thirteen patients (9.4%) developed thrombosis after an average period of 73.0 ± 48.0 months. Independent risk factors for thrombosis were smoking, hypertension, thrombocytopenia, and triple aPL positivity. Low-dose acetyl salicylic acid did not prevent thrombotic events. A total of 28 obstetric complications were detected in 92 pregnancies. During the follow-up, only two women developed obstetric APS. Prophylactic treatment in pregnant women was associated with a better outcome in the prevention of early abortions. The thrombosis rate in patients with positive aPL who do not meet diagnostic criteria for APS is 0.82/100 patients-year. Smoking, hypertension, thrombocytopenia, and the aPL profile are independent risk factors for the development of thrombosis in aPL carriers. Although the incidence of obstetric complications in this population is high (31.6%), only a few of them meet APS criteria. In these women, prophylactic treatment might be effective in preventing early abortions.

Persistent thrombocytopenia predicts poor long-term survival in patients with antiphospholipid syndrome: a 38-year follow-up study

OBJECTIVES

To investigate the impact of thrombocytopenia on survival in patients with antiphospholipid syndrome (APS).

METHODS

Thrombocytopenia and other predictors of outcome were retrospectively evaluated in an antiphospholipid-antibody (aPL)-positive and APS cohort with 38-year follow-up (1980-2018). Thrombocytopenia was defined as < 150 × 109 platelets/l. Hazard ratios (HR) of mortality were calculated using Cox-regression models.

RESULTS

Among 114 patients, 64% had primary APS, 25% secondary APS, and 10% asymptomatic aPL. Mean follow-up was 19 (5-38) years. ANA (HR 1.8, p= 0.10, 95%CI 0.8-3.6), arterial thrombotic events (HR 7.0, p= 0.016, 95%CI 1.4-3.5), myocardial infarction (HR 8.3, p= 0.03, 95%CI 1.1-59), intracardiac thrombosis (HR 17, p= 0.04, 95%CI 1-279), and thrombocytopenia (HR 2.9, p= 0.004, 95%CI 1.4-6.1) were risk factors for all-cause mortality but in multivariate analysis only thrombocytopenia (HR 2.7, p= 0.01, 95%CI 1.3-6.0) remained significant. Persistent (HR 4.4, p= 0.001, 95%CI 2.1-9.2) and low-moderate thrombocytopenia (HR 2.8, p= 0.01, 95%CI 1.2-6.4) were associated with a significant increase in mortality compared with acute (HR 1.6, p= 0.40, 95%CI 0.5-5.3) and severe forms (HR 2.1, p= 0.30, 95%CI 0.5-9.2). APS patients with vs without thrombocytopenia were more frequently male (58% vs 24%, p= 0.001) with arterial thrombosis (55% vs 32%, p= 0.04), LA positivity (100% vs 87%, p= 0.04), type I aPL profile (89% vs 71%, p= 0.05), and anticoagulant treatment (89% vs 63%, p= 0.01). Thrombosis caused 13% of deaths in thrombocytopenic patients and 1% in those without (p= 0.01).

CONCLUSION

Thrombocytopenia is an aPL-related manifestation that identifies patients with severe disease phenotype and high thrombotic risk. Persistent low-moderate thrombocytopenia is associated with a reduced long-term survival.

[The clinical manifestations and risk factors in primary antiphospholipid syndrome with thrombocytopenia]

目的

分析伴血小板减少原发性抗磷脂综合征（PAPS）的临床特征、与血小板减少相关的危险因素以及疾病复发风险。

方法

回顾性分析2009年至2019年间于北京协和医院住院治疗的PAPS患者，比较血小板减少（PLT<100×10⁹/L）和血小板正常患者的临床和实验室检查结果，分析血小板减少患者的临床特征和未来症状再发风险，并应用单因素和多因素Logistic回归分析筛选血小板减少的危险因素。

结果

纳入127例PAPS患者，其中36例（28.3%）合并血小板减少，中位年龄38.0（28.5,51.5）岁，女性占63.9%（13/23），平均血小板计数为（58.9±27.0）×10⁹/L。与血小板正常组（91例）相比，血小板减少组血栓及病理性妊娠发生率差异无统计学意义（P>0.05），自身免疫性溶血性贫血（19.4%对3.3%）、网状青斑（16.7%对3.3%）、慢性肾脏病变（25%对8.8%）、抗磷脂（aPL）抗体三阳性（61.1%对37.4%）发生率均显著增加（P<0.05），补体C3、C4水平显著降低（C3 0.87 g/L对1.07 g/L，C4 0.12 g/L对0.18 g/L，P值均<0.05），中位改良APS总体评分（aGAPSS）显著升高（13分对9分，P＝0.037）。多因素Logistic回归分析显示，低补体血症（OR＝5.032，95%CI 3.118～22.095）是发生血小板减少的危险因素。

结论

PAPS患者血小板减少多为轻中度降低。低补体血症是血小板减少的危险因素。伴血小板减少的PAPS患者再发风险较高。

Management of Non-criteria Manifestations in Antiphospholipid Syndrome

PURPOSE OF THE REVIEW

To review the available evidence on the management of a variety of non-criteria manifestations in antiphospholipid syndrome (APS), including valvular disease, alveolar hemorrhage, thrombocytopenia, hemolytic anemia, APS nephropathy, skin ulcers, livedo reticularis, cognitive dysfunction, and epilepsy.

RECENT FINDINGS

Current treatment relies on low-level evidence and mainly on expert consensus due to the rarity and the heterogeneity of non-criteria APS manifestations and the diversity in management approaches. Conventional anticoagulation and/or antiplatelet APS treatment do not adequately control most of non-criteria manifestations. Increasing knowledge about the contribution of inflammatory in addition to, or independently of, thrombotic mechanisms in non-criteria APS manifestations provides insight into the potential effect of novel therapies targeting B-cells, mammalian target of rapamycin, neutrophil, and complement or interferon pathways. Existing evidence is limited by lack of high-quality studies. Better understanding of the pathophysiology and clinical phenotypes of APS and well-designed prospective studies of homogenous populations are needed to provide evidence-based recommendations for the management of non-criteria APS manifestations.

Cryptic conspirators: a conversation about thrombocytopenia and antiphospholipid syndrome

Purpose of review

Although antiphospholipid syndrome (APS) is best known for conveying increased risk of thrombotic events and pregnancy morbidity, thrombocytopenia is also recognized as a common association. In this review, we will explore the relationship between thrombocytopenia and APS, highlighting our evolving understanding – and persistent knowledge gaps – through clinically oriented questions and answers.

Recent findings

A history of thrombocytopenia likely portends a more severe APS phenotype (including increased risk of thrombosis). Although the pathophysiology underlying thrombocytopenia in APS has yet to be definitively revealed, mechanisms that play a role (at least in subsets of patients) include: immune thrombocytopenic purpura/ITP-like autoantibodies against platelet glycoproteins; antiphospholipid antibody (aPL)-mediated platelet activation and consumption; and potentially life threatening thrombotic microangiopathy. Although thrombocytopenia is often ‘mild’ in APS (and therefore, may not require specific therapy), there are causes of acute-onset thrombocytopenia that mandate emergent work-up and treatment. When APS-related thrombocytopenia does require therapy, the approach must be individualized (requiring an understanding of pathophysiology in the particular APS patient). For patients with ITP-like disease, rituximab is emerging as a popular approach to treatment; in contrast, there are hints that thrombopoietin mimetics may be associated with elevated thrombotic risk.

Summary

Thrombocytopenia is common in APS, and is likely associated with more severe disease. Improved understanding of thrombocytopenia in APS has the potential to improve risk stratification, reveal novel aspects of APS pathophysiology, and lead to treatments that are more individualized and holistic.

Recommendations of the Spanish Rheumatology Society for Primary Antiphospholipid Syndrome. Part I: Diagnosis, Evaluation and Treatment

OBJECTIVE

The difficulty in diagnosis and the spectrum of clinical manifestations that can determine the choice of treatment for primary antiphospholipid syndrome (APS) has fostered the development of recommendations by the Spanish Society of Rheumatology (SER), based on the best possible evidence. These recommendations can serve as a reference for rheumatologists and other specialists involved in the management of APS.

METHODS

A panel of four rheumatologists, a gynaecologist and a haematologist with expertise in APS was created, previously selected by the SER through an open call or based on professional merits. The stages of the work were: identification of the key areas for drafting the document, analysis and synthesis of the scientific evidence (using the Scottish Intercollegiate Guidelines Network [SIGN] levels of evidence) and formulation of recommendations based on this evidence and formal assessment or reasoned judgement techniques (consensus techniques).

RESULTS

46 recommendations were drawn up, addressing five main areas: diagnosis and evaluation, measurement of primary thromboprophylaxis, treatment for APS or secondary thromboprophylaxis, treatment for obstetric APS and special situations. These recommendations also include the role of novel oral anticoagulants, the problem of recurrences or the key risk factors identified in these subjects. This document reflects the first 21, referring to the areas of: diagnosis, evaluation and treatment of primary APS. The document provides a table of recommendations and treatment algorithms.

CONCLUSIONS

An update of the SER recommendations on APS is presented. This document corresponds to partI, related to diagnosis, evaluation and treatment. These recommendations are considered tools for decision-making for clinicians, taking into consideration both the decision of the physician experienced in APS and the patient. A partII has also been prepared, which addresses aspects related to obstetric SAF and special situations.

Effect and mechanism of the aβ2‑GP I/rhβ2‑GP I complex on JEG‑3 cell proliferation, migration and invasion

Antiphospholipid antibody (aPL)-mediated antiphospholipid syndrome (APS) is an autoimmune disease. Upon binding to aPL, the primary antigen of aPL, β2-glycoprotein I (β2-GP I), induces abnormal immune function, which further activates downstream signaling pathways in the cell and eventually leads to APS. The present study aimed to determine whether β2-GP I antigen and anti-β2-glycoprotein I antibody (aβ2-GP I), which belong to the aPL class of antibodies, may affect human chorionic epithelium cell (JEG-3) proliferation, migration and invasion. Recombinant human (rh)β2-GP I protein was expressed using a prokaryotic expression system and aβ2-GP I antibody was purified from the blood serum of 10 patients with recurrent pregnancy loss. JEG-3 cells were stimulated with rhβ2-GP I and aβ2-GP I separately or simultaneously, and serum immunoglobulin G of normal pregnant women was used as negative control. Using cell counting kit-8, cell cycle and transwell assays in addition to EdU staining, it was determined that aβ2-GP I/rhβ2-GP I complex markedly increased JEG-3 cell proliferation, migration and invasion. The results revealed that mRNA levels of inhibitor of nuclear factor (NF)-κB kinase subunit (IKKβ), myeloid differentiation primary response protein MyD88 (MyD88), NF-κB and NF-κB inhibitor α (IκBα), as well as the protein levels of MyD88, IκBα and phospho(p)-IκBα in JEG-3 cells increased following incubation with the aβ2-GP I/rhβ2-GP I complex. The observed upregulation of p-IκBα protein suggested that IκBα-mediated inhibition of NF-κB was weakened. Furthermore, JEG-3 cells were transfected with PGMLV-NF-κB-Lu vector. Luciferase activity in JEG-3-NFκB-Luc1 and JEG-3-NFκB-Luc2 cells was enhanced following treatment with aβ2-GP I/rhβ2-GP I complex. The present study demonstrated that aβ2-GP I/rhβ2-GP I complex activates NF-κB through MyD88 signal transduction pathway, which further enhances JEG-3 cell proliferation, migration and invasion.