The (reverse) paradox of lupus anticoagulant: A case report.

INTRODUCTION: Systemic Lupus Erythematosus (SLE) is often associated with antiphospholipid syndrome (APS), which manifests as recurrent thrombotic events or obstetric complications in presence of antiphospholipid antibodies. Hereby we present a case of a child who presented with low grade fever, superficial thrombophlebitis with mucosal bleeding and was diagnosed as Lupus Anticoagulant Hypoprothrombonemia Syndrome (LAHS). CASE: A 7-year-old girl was hositalized with complaints of fever and spontaneous bleeding from gums and epistaxis. On examination, she had multiple small tender nodular lesions with greenish hue of overlying skin suggesting superficial thrombophlebitis and mild non-tender hepatosplenomegaly. Her coagulogram revealed normal platelet counts and deranged PT and APTT. ESR and CRP were raised. Serology for viral infections, blood and urine cultures were negative. Patient had persistent coagulopathy, mucosal bleeding and low-grade fever despite supportive treatment. She was tested for anti-nuclear antibodies (ANA) in view of suspicion of autoimmune process. ANA was positive in high titer with speckled pattern on indirect immunofluorescence. Mixing studies showed correction of PT and non-correction of APTT. PT based factors were normal except for prothrombin (FII) which was low and remained low despite dilution. APTT based factors (FVIII and FIX) were low but corrected on dilution. This was suggestive of prothrombin deficiency and a presence of a nonspecific inhibitor of APTT pathway (likely lupus anticoagulant). Presence of antiprothrombin antibodies established the diagnosis of LAHS. ENA profile was positive for SmD1, Ro60 and Ku. Complement levels were low. Direct Coomb's test was positive but there was no evidence of hemolysis. Lupus anticoagulant by DRVVT and anti-cardiolipin antibodies by ELISA were positive. Patient was diagnosed as Systemic Lupus Erythematosus with Lupus Anticoagulant Hypoprothrombinemia Syndrome. She was treated with IV methylprednisolone. Patient showed significant improvement in form of resolution of fever, mucosal bleeding, correction of deranged INR and reversal of hypocomplementemia. She was discharged on hydroxychloroquine, mycophenolate mofetil and tapering doses of prednisolone. On follow up, child was doing well and her prothrombin time and complement levels had normalized. Low dose aspirin was aspirin was added for thromboprophylaxis.

Antiphospholipid syndrome in children.

Antiphospholipid syndrome (APS) in children is a rare disease associated with significant morbidity and mortality. In comparison with APS in adults, pediatric APS has a more severe presentation with frequent recurrences of thrombotic events and a higher probability of life-threatening catastrophic APS. Nonthrombotic manifestations are also more common in the pediatric age group and can precede thrombosis. New classification criteria have been introduced recently and have not yet been assessed in pediatric patients with APS. In addition to anticoagulation drugs, other novel therapies have emerged including the use of B cell and complement inhibitors, especially in catastrophic APS. The purpose of this review is to provide a broad overview of aPL-related clinical manifestations in pediatric patients based on the analysis of published cohorts and data from the international pediatric APS registry. We also aim to illustrate APS in infants caused by transplacentally transferred maternal aPL, which is very rarely associated with acute thrombotic events in the perinatal period and more frequently with long-term neurodevelopmental abnormalities.

Antiphospholipid Antibody Testing in a Maximum Care Hospital: Method-Dependent Differences.

Background: Antiphospholipid antibody (aPL) testing is critical for the classification of antiphospholipid syndrome. The 2023 ACR/EULAR classification criteria recommend the use of enzyme-linked immunosorbent assays (ELISAs) and specific thresholds for aPL positivity. Since non-ELISA methods are increasingly used, we compared and evaluated ELISA and non-ELISA aPL assays in a real-world maximum care hospital setting. Methods: Between January 2021 and June 2024, anticardiolipin (aCL; IgG and IgM) and anti-beta2 glycoprotein I (aß2GPI; IgG and IgM) antibodies were measured using ELISA (n = 5115) and a chemiluminescence-based automated immunoassay (CLIA) (n = 3820). Results of parallel testing were compared, and associations with clinical and laboratory characteristics were evaluated. Results: A total of 946 samples were tested using ELISA and CLIA in parallel. A total of 136 (14%) specimens were positive for at least one aPL, and 55 (6%) specimens were from patients diagnosed with APS. Among the latter, 47 (85%) and 41 (75%) patients were positive when ELISA- or CLIA-based aPL assays were used, respectively. After applying the >40 units threshold of the new classification criteria, the number of aPL-positive specimens was significantly lower. In the entire cohort, the agreement between ELISA and CLIA aPL assays was acceptable only for aß2GPI IgG; the results from the two methods did not agree for aCL IgG/IgM and aß2GPI IgM. In APS patients, the agreement between ELISA and CLIA aPL assays was acceptable for aß2GPI IgG and IgM but poor for aCL IgG and IgM. Antibody levels in APS patients were significantly higher using CLIA compared to ELISA. Conclusions: The method-dependent discrepancies between ELISA- and CLIA-based aPL assays regarding the quantitative and qualitative results are substantial. Both methods are suitable for APS classification, but the choice of aPL assay may influence the classification, and therefore, aPL results should be interpreted carefully in the clinical context.

Study of electrocardiographic corrected QT interval and QT dispersion abnormalities, erythrocyte sedimentation rate, serum uric acid in patients with systemic lupus erythematosus.

INTRODUCTION: Systemic Lupus Erythematosus (SLE) is an autoimmune disease having a variety of clinical symptoms because of multiple organs being affected at once or progressively over time. Cardiovascular system (CVS) involvement is the third most frequent cause of death in SLE, among other factors. The prognosis can be determined by looking at QT interval measurements, which have shown an elevated risk of mortality from cardiovascular causes. METHODS: A case-control study was conducted on 80 patients (40 SLE patients and 40 controls) for a duration of 16 months. SLE patients and controls were identified from the general medicine and rheumatology outpatient department (OPD) based on the inclusion criteria. A thorough clinical examination was performed after obtaining a detailed clinical history. Baseline blood tests were then performed on the SLE patients and ECG was taken from both cases and controls. The serum uric acid level was measured using an automated analyzer, and the ESR was computed using Westergren's Method. The corrected QT interval (QTc) was estimated using Bazett's method. All the collected data were compared and analyzed using IBM SPSS Statistics version 23.0. RESULTS: The majority of age distribution among SLE patients and controls was 21-25 years (37.5%) (Mean - 15.7 ± 14.9 years). Duration of SLE was predominantly reported between 1 and 12 months (62.5%). Very high (40%) and high (40%) lupus disease activity was recorded in the majority as per the SELENA-SLEDAI score. There was a significant difference between QTc values among SLE patients and controls (t- 8.117) (p-.0005). Upon correlating SLEDAI with the QTc, QTd, ESR, and Uric acid parameters among the SLE patients, ESR parameters were found to be moderately correlated (r-0.460) with the SLEDAI which was statistically significant (p- .003). CONCLUSION: QTc interval and ESR values can be a simple and potential method for early detection of cardiac involvement in SLE patients with active disease activity. This will not only facilitate early diagnosis of disease activity, but it will also provide an affordable and accessible avenue for low and middle-income countries to decrease the SLE burden.

Antiphospholipid antibody testing.

Antiphospholipid antibodies (aPL) are a family of autoantibodies targeting phospholipid-binding proteins and are associated with several clinical settings, and most notably define the antiphospholipid syndrome (APS). These antibodies can be identified using a variety of laboratory tests, which include both solid-phase immunological assays and functional clotting assays that detect lupus anticoagulants (LA). aPLs are linked to a range of adverse medical conditions, such as thrombosis and complications affecting the placenta and fetus, potentially leading to morbidity and mortality. The specific aPL identified, along with the pattern of reactivity, correlates with the severity of these conditions. Therefore, laboratory testing for aPL is crucial for evaluating the risk of complications and for fulfilling certain classification criteria for APS, which are also applied as diagnostic markers in medical practice. This review provides an overview of the available laboratory tests currently for measuring aPL and discusses their clinical implications.

The relevance of antiphospholipid antibodies in obstetrics.

AIM AND METHODOLOGY: To provide a comprehensive review on new findings and current recommendations regarding antiphospholipid antibodies with particular emphasis on clinical impact on gestation. CONCLUSION: Antiphospholipid antibodies are an important risk factor for the development of a series of pregnancy-related complications. Early diagnosis and appropriate therapy can reduce the incidence of pregnancy loss and pregnancy-related complications.

Antiphospholipid antibodies in patients with antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is a rare systemic autoimmune disease characterized by recurrent pregnancy morbidity or thrombosis in combination with the persistent presence of antiphospholipid antibodies (aPLs) in plasma/serum. Antiphospholipid antibodies are a heterogeneous, overlapping group of autoantibodies, of which anti-ß2-glycoprotein I (aß2GPI), anticardiolipin (aCL) antibodies and antibodies that prolong plasma clotting time in tests in vitro known as lupus anticoagulant (LAC) are included in the laboratory criteria for the diagnosis of APS. The presence of LAC antibodies in plasma is indirectly determined by measuring the length of coagulation in two tests - activated partial thromboplastin time (aPTT) and diluted Russell's viper venom time (dRVVT). The concentration of aß2GPI and aCL (immunglobulin G (IgG) and immunoglobulin M (IgM) isotypes) in serum is directly determined by solid-phase immunoassays, either by enzyme-linked immunosorbent assay (ELISA), fluoroimmunoassay (FIA), immunochemiluminescence (CLIA) or multiplex flow immunoassay (MFIA). For patient safety, it is extremely important to control all three phases of laboratory testing, i.e. preanalytical, analytical and postanalytical phase. Specialists in laboratory medicine must be aware of interferences in all three phases of laboratory testing, in order to minimize these interferences. The aim of this review was to show the current pathophysiological aspects of APS, the importance of determining aPLs-a in plasma/serum, with an emphasis on possible interferences that should be taken into account when interpreting laboratory findings.

Noncriteria antiphospholipid antibodies in antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombotic manifestations and/or obstetric complications in patients with persistently positive antiphospholipid antibodies (aPL). aPL are a heterogeneous group of autoantibodies, but only lupus anticoagulant, anticardiolipin (aCL), and antibeta2-glycoprotein I antibodies (aß2GPI) IgG or IgM are included as laboratory classification criteria. Seronegative APS patients are usually defined as patients with the clinical symptoms of APS but who test negative for aPL. The negativity to classic aPL criteria does not exclude the presence of other aPL. Several noncriteria aPL have been identified. Some noncriteria aPL are well studied, such as IgA aCL and aß2GPI, the antiphosphatidylserine-prothrombin (aPS/PT) antibodies, and the antibodies against the domain I of beta2-glycoprotein I (aDI), both latter groups receiving more attention for their role in thrombotic events and pregnancy complications. Other noncriteria aPL that have been studied are antibodies against annexin V, prothrombin, phosphatidylethanolamine, phosphatidic acid, phosphatidylserine, phosphatidylinositol, vimentin-cardiolipin complex, anti-protein S/protein C. Measurement of some of these noncriteria aPL (aPS/PT, aDI) is useful in the laboratory work-out of APS in specific situations. We have to differentiate between patients who are positive for noncriteria aPL only, and patients who have both criteria and noncriteria aPL to enable us to study their role in the diagnosis or risk stratification of APS. The research on noncriteria aPL is continually developing as the clinical relevance of these antibodies is not yet fully clarified.

Skin erythematous migrant lesions consistent with histologically confirmed dermal arteriolar thrombosis connected to APS.

Antiphospholipid syndrome (APS) is an acquired thrombophilic disorder related to the presence of antiphospholipid antibodies (LAC, anticardiolipin, anti Beta2-glycoprotein) known to cause venous and arterial thrombosis and recurrent pregnancy loss. Skin disorder is a frequent finding usually due to vascular thrombosis involving the dermal layer and can be either localized or widespread causing necrosis and ulceration of the skin, without histological evidence of vasculitis. We present a case of a woman with APS with both arterial and venous thrombotic involvement associated with an atypical dermatological manifestation histologically consistent with a pauci-inflammatory intermediate-deep dermal arteriolar platelet-mediated thrombosis that appeared despite anticoagulation with warfarin and responding to the addition of antiplatelet therapy.

Anticardiolipin Antibody Plays a More Important Role Than Anti-ß2-Glycoprotein I Antibody in Activating Complement in Patients with Lupus Nephritis.

Objective: This research aimed to explore the correlation between antiphospholipid antibodies (aPLs) and complement activation in lupus nephritis (LN) patients. Methods: A retrospective analysis was carried out on patients diagnosed with LN based on renal biopsy from June 2019 to June 2022. The study assessed levels of IgM, IgA, and IgG subtypes of anticardiolipin antibodies (aCLs) and anti-ß2-glycoprotein I (anti-ß2-GPI) antibodies. Pathological and clinical data were collected concurrently with the renal biopsy. Results: The analysis included 76 LN patients, with 44.7% testing positive for aPLs. LN patients with positive aPLs exhibited increased hematuria, higher SLEDAI scores, reduced serum C3 and C4 levels, and more C1q deposits in the glomerulus compared to those with negative aPLs (P<0.05). Correlation analysis demonstrated the inverse relationships between IgG-aCL levels and serum C3 and C4 levels (r=-0.29, P=0.005; r=-0.24, P=0.016, respectively), as well as a positive correlation with C4 deposits in the glomerulus (r=0.20, P=0.041). Conclusion: This investigation suggests that aPLs, particularly IgG-aCLs, may be associated with the severity of LN and could contribute to the activation of classical complement pathways.

Anticardiolipin Antibody Determination to Guide Q Fever Treatment.

Query (Q) fever is a worldwide infectious disease with acute and chronic manifestations caused by Coxiella burnetii. The clinical manifestations are so variable that the disease is often only diagnosed if systematically considered as a differential diagnosis. Here, we present a case of a 39-year-old man who lived in a countryside house, with cattle and sheep in his field, with acute Q fever hepatitis with the typical granulomatous arrangement in the liver biopsy. The diagnosis was confirmed by polymerase chain reaction (PCR) assay in a serum sample and the presence of phase II antibodies. Anticardiolipin antibody (aCL) determination at diagnosis of acute Q fever and during follow-up was made to persecute early identification and to guide the treatment and prophylaxis of possible complications, such as endocarditis.

Viewpoint: Provoked thrombosis in antiphospholipid syndrome.

Unprovoked thrombosis (thrombosis occurring without an established environmental factor favouring the episode) is a classic feature of APS. In the general population, provoked venous thromboembolism (VTE) is clearly defined and has clinical and therapeutic differences compared with unprovoked VTE. Whether provoked VTE in the context of APS may lead to a limited treatment duration is not well established. Therefore, careful clinical and laboratory evaluation is needed to identify patients eligible for a limited duration of anticoagulation treatment after provoked VTE. Given the uncertainties of available data, the risks and benefits of treatment decisions should be clearly explained. Decisions should be shared by both the patient and physician. Cardiovascular risk factors are common in patients with APS with arterial thrombosis. There are insufficient data suggesting that cardiovascular risk factor control would allow the cessation of anticoagulation. In most instances, arterial thrombosis will require prolonged anticoagulants. A careful analysis of clinical characteristics and laboratory evaluation, particularly the aPL antibody profile, is needed to make decisions on a case-by-case basis.

Antiphospholipid (Hughes) syndrome 40th anniversary.

This article is a celebration of the 40th anniversary of APS, a disease that appears to affect one in 2000 people. The quality of life of patients affected has improved significantly as a result of early diagnosis and effective treatment.

IgA is the predominant isotype of anti-ß2 glycoprotein I in patients with COVID-19.

OBJECTIVE: The aim of this research was to determine the frequency of antiphospholipid antibodies (aPL) in patients with COVID-19. METHODS: The frequency and titers of anticardiolipin antibodies (aCL) and anti-ß2 glycoprotein I antibodies (aß2GPI) were determined in sera of adult patients hospitalized with COVID-19. Immunoglobulin (Ig)G, IgA, IgM aCL, and aß2GPI were measured using enzyme-linked immunosorbent assay. RESULTS: Eighty-three patients were included in the study. The mean age of patients was 62 ± 13.9 years, ranging from 23 to 86 years. Stratification according to severity of infection divided patients in 2 groups: 45 patients with moderate infection and 38 patients with critical or severe infection. Out of the 83 patients suffering from COVID-19, aPL (aCL or aß2GPI) were detected in 24 patients (28.9%). IgG, IgA and IgM aß2GPI were positive in 2.4%, 16.9% and 8.4%, respectively. IgG, IgA and IgM aCL showed positivity in 7.2%, 0%, and 4.8%, respectively. The frequency of aPL was 36.8% in patients with critical/severe infection and 22.2% in patients with moderate infection. In critical/severe patients, the frequency of aß2GPI was significantly higher than aCL (34.2% vs 13.2%, P = .03) and aß2GPI-IgA were significantly more frequent than aß2GPI-IgG (21.1% vs 2.6%, P = .028). CONCLUSION: In this cross-sectional study, aPL and particularly aß2GPI-IgA were common in patients with COVID-19.

Antiphospholipid Antibodies and Vascular Thrombosis in Patients with Severe Forms of COVID-19.

Antiphospholipid antibodies (aPLA) are a laboratory criterion for the classification of antiphospholipid syndrome (APS) and are known to cause clinical symptoms such as vascular thrombosis or obstetric complications. It is suggested that aPLA may be associated with thromboembolism in severe COVID-19 cases. Therefore, we aimed to combine clinical data with laboratory findings of aPLA at four time points (admission, worsening, discharge, and 3-month follow-up) in patients hospitalized with COVID-19 pneumonia. In 111 patients with COVID-19 pneumonia, current and past history of thrombosis and pregnancy complications were recorded. Nine types of aPLA were determined at four time points: anticardiolipin (aCL), anti-ß2-glycoprotein I (anti- ß2GPI), and antiphosphatidylserine/prothrombin (aPS/PT) of the IgM, IgG, or IgA isotypes. During hospitalization, seven patients died, three of them due to pulmonary artery thromboembolism (none were aPLA positive). Only one of the five who developed pulmonary artery thrombosis was aPLA positive. Out of 9/101 patients with a history of thrombosis, five had arterial thrombosis and none were aPLA positive at admission and follow-up; four had venous thrombosis, and one was aPLA positive at all time points (newly diagnosed APS). Of these 9/101 patients, 55.6% were transiently aPLA positive at discharge only, compared to 26.1% without a history of thrombosis (p = 0.041). Patients with severe forms of COVID-19 and positive aPLA should receive the same dose and anticoagulant medication regimen as those with negative aPLA because those antibodies are mostly transiently positive and not linked to thrombosis and fatal outcomes.

Hyperoside exerts protective effects against anticardiolipin antibody-induced recurrent pregnancy loss in vivo and in vitro.

BACKGROUND: Women with antiphospholipid syndrome (APS) or antiphospholipid antibodies (aPLs) are at high risk for obstetric complications, including recurrent pregnancy loss (RPL). However, effective treatments for RPL are lacking. OBJECTIVE: This study aimed to reveal the function and underlying mechanism of hyperoside (Hyp) in RPL associated with antiphospholipid antibodies (aCLs). METHODS: The pregnant rats (N = 24) were divided randomly into four groups: normal human-IgG (NH-IgG); aCL-pregnancy loss (aCL-PL); aCL-PL + Hyp (40 mg/kg/day); aCL-PL + low molecular weight heparin (LMWH, 525 µg/kg/day). HTR-8 cells were treated with 80 µg/mL aCL to establish the cell models of miscarriage. RESULTS: In pregnant rats, aCL-IgG injection raised the abortion rate of embryos, while Hyp treatment inhibited the effects. Additionally, Hyp inhibited the platelet activation and uteroplacental insufficiency caused by aCL. In vivo and in vitro experiments further suggested that Hyp suppressed aCL-induced inflammation and apoptosis by downregulating NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome-related factors and decreasing apoptotic rates. After aCL administration, Hyp therapy downregulated the expression of purinergic ligand-gated ion channel 7 (P2X7), which is reported to induce cytokine release and apoptosis. Furthermore, we found that the treatment of 3'-O-(4-Benzoyl) benzoyl-ATP (BzATP, an agonist of the P2X7 receptor) reversed the inhibitory effects of Hyp on cell function. CONCLUSIONS: Hyp exerts protective effects on aCL-induced pregnancy loss by preventing platelet activation-mediated P2X7/NLRP3 pathway. Therefore, Hyp may provide a feasible pharmaceutical strategy for the treatment of RPL.

Antiphospholipid antibodies in pulmonary embolism treated with direct oral anticoagulants: Prevalence data from unselected consecutive patients.

Background: Direct oral anticoagulants (DOACs) are the first-choice treatment option for the prevention of the recurrence of venous thrombosis in patients with pulmonary embolism (PE); however, their effect in patients with antiphospholipid syndrome (APS) is challenged. Therefore, the prevalence of antiphospholipid autoantibodies in patients with PE is noteworthy. Objectives: To determine the prevalence of unselected patients presenting with PE who meet the criteria for APS based on elevated levels of anticardiolipin (aCL) and anti-ß2-glycoprotein I (aß2GPI) antibodies. Methods: Consecutive patients with PE, in whom DOACs were primarily initiated, were tested for aCL and aß2GPI. If the levels were elevated, the tests were repeated after 12 weeks for APS diagnosis. Laboratory results and patient characteristics were retrospectively collected from a laboratory information system and electronic patient journal entries over a 2-year period. Results: The prevalence of APS based on consistently elevated levels of aCL or aß2GPI was 3.7% (10 of 267 patients). Three patients were double positive. In 11 out of 21 patients (52%) with initially elevated values, the levels of the antibodies normalized after 12 weeks. The patient characteristics were largely similar in those with APS and those without APS; however, patients with APS tended to be older and more likely to receive antithrombotic treatment at the time of PE. Conclusion: We found a relatively low prevalence of APS based on aCL or aß2GPI. The high rate of normalized levels of the antibodies after 12 weeks reaffirms the need for repeated tests for APS diagnosis. Older patients more frequently met the criteria for APS. Determining the effectiveness of DOACs in non-triple-positive patients with APS following venous thromboembolism is important to further determine the feasibility of unselected tests in patients with PE.

Levels and avidities of antiphosphatidylethanolamine antibodies in patients with thrombotic events and immunologically-mediated diseases.

AIMS: Antiphosphatidylethanolamine antibodies (aPE) represent one type of antiphospholipid antibody (aPL) directed against the neutral phospholipids - phosphatidylethanolamines. The aim of this study was to evaluate levels and avidities of aPE in several groups of patients and compare them with conventional aPLs. METHODS: aPE were analysed in a cohort consisting of 68 hospitalized patients. The other cohort comprised 22 patients with immunologically-mediated diseases. The control group consisted of 20 healthy persons. ELISA methods were used for determination of aPL. Avidities of aPE were tested by modified ELISA with urea as a chaotropic agent. RESULTS: aPE IgG/IgM were significantly higher in the group of patients with venous thromboembolism than those with non-thrombotic internal disorders (P=0.02 for both Ig classes). aPE IgG/IgM elevated above cut-off values were found in 10.8% of patients with venous thromboembolism and as a single aPL in 6.5%. Levels of aPE IgG higher than our limit (>6 U/mL) were detected in 29% of patients with immunologically-mediated diseases with other positive aPL. Low-, intermediate- and high-avidity aPE IgG were found in patients of both cohorts. The avidities of aPE IgG differed from those of anticardiolipin antibodies IgG. Neither aPE IgG levels nor avidity dynamics significantly changed during follow-up. CONCLUSION: aPE may be related to venous thromboembolism and may be part of the repertoire of aPL in immunologically-mediated diseases. There are patients with thrombosis negative for conventional aPL but positive for aPE. aPE IgG may have different avidities.

COVID-19 and antiphospholipid antibodies.

Antiphospholipid syndrome and the coagulopathy of COVID-19 share many pathophysiologic features, including endotheliopathy, hypercoagulability, and activation of platelets, complement pathways, and neutrophil extracellular traps, all acting in concert via a model of immunothrombosis. Antiphospholipid antibody production in COVID-19 is common, with 50% of COVID-19 patients being positive for lupus anticoagulant in some studies, and with non-Sapporo criteria antiphospholipid antibodies being prevalent as well. The biological significance of antiphospholipid antibodies in COVID-19 is uncertain, as such antibodies are usually transient, and studies examining clinical outcomes in COVID-19 patients with and without antiphospholipid antibodies have yielded conflicting results. In this review, we explore the biology of antiphospholipid antibodies in COVID-19 and other infections and discuss mechanisms of thrombogenesis in antiphospholipid syndrome and parallels with COVID-19 coagulopathy. In addition, we review the existing literature on safety of COVID-19 vaccination in patients with antiphospholipid antibodies and antiphospholipid syndrome.