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Objectives: The percentage of autoimmune diseases in Western countries is approximately 8% of the total population. Despite numerous studies indicating an increase in prevalence and incidence over the past two decades, autoimmune vestibular disorders seem to be underdiagnosed, primarily due to the lack of a definitive test capable of identifying the specific antigen of the inner ear. Autoimmune inner ear disease (AIED) is defined as a rapidly progressive and often fluctuating bilateral neurosensorial hearing loss that develops over a period of weeks or months. AIED can affect only the inner ear or be part of systemic diseases such as granulomatosis with polyangiitis, Cogan's syndrome, systemic lupus erythematosus, polyarteritis nodosa, or relapsing polychondritis, among others. Our main objective was to conduct a study on the presence of antiphospholipid antibodies (aPL) in patients with AIED seen in a specialised clinic., Methods: We designed an observational retrospective study in which we selected patients from a total group of 55 with AIED referred to the Autoimmune Diseases Clinic, those with confirmed positivity for antiphospholipid antibodies, and described their clinical, analytical, and epidemiological characteristics., Results: We found a prevalence of 29% positivity for antiphospholipid antibodies, with lupus anticoagulant (LA) being the most frequently detected, followed by anticardiolipin (aCL) and anti-beta2 glycoprotein (anti-B2GP). Double positivity was observed in 25% of patients. The main clinical manifestations were bilateral hearing loss, vestibular symptoms, and tinnitus. Only 25% of patients experienced audiometric improvement during the course of the disease., Conclusions: We emphasise the importance of identifying the presence of aPL in AIED, enabling the establishment of appropriate and specific therapeutic management to prevent audiometric deterioration.

Lupus anticoagulant (LA) is one of three tests identified as laboratory criteria for definite antiphospholipid syndrome (APS). The other two tests are anticardiolipin antibody (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibody. The presence of LA is assessed using clot-based tests, while the presence of aCL and aβ2GPI is assessed by immunological assays. Since no test can be considered 100% sensitive or specific for LA, current guidelines recommend using two different clot-based assays reflecting different principles, with the dilute Russell viper venom time (dRVVT) and activated partial thromboplastin time (aPTT) recommended. Initially, LA-sensitive reagents are used to screen for LA, and then, in "screen-positive" samples, LA-"insensitive" reagents are used to confirm LA. Because LA assays are based on clot detection, anything that can interfere with fibrin clot development may affect test results. In particular, in addition to LA, the tests are also sensitive to the presence of a wide range of clinical anticoagulants, reflecting preanalytical issues for testing. We provide updated findings for LA testing in our geographic region, using recent data from the Royal College of Pathologists of Australasia Quality Assurance Programs, an international external quality assessment program with approximately 120 participants. Data show a wide variety of assays in use, especially for aPTT testing, and variable outcomes in reported numerical values with these assays when assessing proficiency samples. dRVVT testing mostly comprised reagents from three main manufacturing suppliers, which also showed differences in numerical values for the same homogeneous tested samples. Nevertheless, despite the use of different test reagents and processes, >98% of participants correctly identified LA-negative samples as LA-negative and LA-positive samples as LA positive. We hope our findings, reflecting on the heterogeneity of test processes and test data, help improve diagnostic testing for LA in the future., Competing Interests: None declared., (Thieme. All rights reserved.)

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., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Antiphospholipid antibodies (aPL), including lupus anticoagulant, antibodies against β 2 glycoprotein I (anti-β2GPI), and anticardiolipin (aCL) antibodies are associated with ischemic stroke (IS). Their prevalence and clinical relevance in atrial fibrillation (AF) remain unclear., Objectives: To assess whether aPL are associated with increased risk of IS in AF patients despite anticoagulation., Methods: We conducted a post hoc analysis of aPL using blood samples from 243 consecutive AF patients enrolled in a cohort study. Markers of a prothrombotic state, including endogenous thrombin potential, fibrin clot permeability, and lysis time, were measured at baseline. During a median follow-up of 52 months, IS/transient ischemic attack and major bleeding were recorded., Results: We observed aPL at a moderate or high titer in 51 (21%) patients, including 17 (7%) with anti-β2GPI, 19 (7.8%) with aCL antibodies, and 37 (15.2%) with lupus anticoagulant. aPL-positive patients were more likely to have prior stroke (P = .01) and be active smokers (P = .03), along with increased endogenous thrombin potential (P = .02), without any changes in fibrin clot properties. Anti-β2GPI (hazard ratio, 4.38; 95% CI, 1.58-12.19) and aCL (hazard ratio, 4.70; 95% CI, 1.80-12.30) at a moderate or high titer were associated with IS during follow-up (n = 20; 1.9% per year). There were 23 major bleedings (2.1% per year) and 20 deaths (1.9% per year), which were not associated with aPLs., Conclusion: Our study showed a relatively high prevalence of aPL positivity in AF patients, which was linked to an increased risk of IS/transient ischemic attack. This suggests that screening for aPL might help optimize anticoagulant therapy in such patients., Competing Interests: Declaration of competing interests All authors have no competing interests to disclose., (Copyright © 2024 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2024 The Author(s). Published by Elsevier España, S.L.U. All rights reserved.)

Background: Clot based assays used for lupus anticoagulant (LAC) detection are typically interpreted in a qualitative fashion and may not reflect LAC potency. In this cross-sectional study, we describe a method for quantifying the LAC titer using serial (dependent) two-fold dilutions in normal pooled plasma., Methods: Serial dilutions of 51 residual plasma samples from 50 patients were tested using the Russell's viper venom screening time (DRVVT) and activated partial thromboplastin screening time (APTT) methodologies. The measured clotting times and the corresponding dilution factors were then used to derive a four-parameter logistic model. The LAC titer for each patient was interpolated as the sample dilution that corresponds to the upper reference interval limit of the corresponding assay., Results: Calculated APTT and DRVVT LAC titers displayed a strong linear correlation (R 2  = 0.84) between each other, but not with the degree of prolongation of the APTT/DRVVT screening time in the neat undiluted samples. Using data driven partitioning, patients could be grouped into low (<10) or high (≥10) DRVVT LAC titer. There were no significant differences in anticardiolipin (aCL) or anti-beta 2 glycoprotein 1 (aB2GPI) antibody levels or prevalence of thromboembolic events between low and high LAC titer groups. In contrast, antiphosphatidylserine/prothrombin (aPS/PT) IgM antibody levels, but not IgG, were significantly higher in the high LAC titer group., Conclusions: The degree of prolongation of the APTT/DRVVT screening time is not correlated with the LAC titer. Only aPS/PT IgM antibodies levels were strongly correlated with the LAC titers. Additional studies are warranted to determine clinical implications of high LAC titers., (© 2024 John Wiley & Sons Ltd.)

Introduction: Thorough assessment of the antiphospholipid syndrome (APS) includes retesting of positive antiphospholipid antibody (aPL) tests after at least 12 weeks, and a full antiphospholipid antibody profile. To what extent this work-up is done in clinical practice is unknown., Methods: Data on 25 116 in- and out-hospital patients tested for the presence of lupus anticoagulant (LA), the aPL which most strongly correlates with thrombosis, was extracted from the laboratory information system of the only laboratory that performs LA tests in the Capital Region, Denmark. We estimated fraction of repeated tests, tests repeated within the recommended time span, and fraction with a full aPL profile., Results: Out of 25 116 patients, 843 were positive for LA (3.3%), and 3948 results were inconclusive (16%). Only 51% (95% CI of the proportion: 48%-54%) (n = 431) of positive tests were repeated. The proportion of inconclusive LA test results increased from 13% (12%-15%) in 2009 to 20% (19%-22%) in 2020. Out of the positive tests repeated within the first year, only 60/353 (17%; 13%-21%) were repeated within 12-16 weeks; 177/353 (50%; 45%-55%) were re-tested within the first 12 weeks of first positive test result. The proportion of patients with a full antiphospholipid antibody profile increased from 161/1978 (8%) in 2010 to 1041/1978 (43%) in 2020., Conclusion: We found several issues with the laboratory workup of APS. This indicates a need for increased awareness of comprehensive laboratory assessment of possible APS as well as a closer collaboration between the laboratory and clinicians., (© 2024 The Authors. International Journal of Laboratory Hematology published by John Wiley & Sons Ltd.)

Background: Improving harmonization of the clinical interpretation of anticardiolipin (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies immunoglobulin G (IgG)/immunoglobulin M (IgM) in the diagnosis of antiphospholipid syndrome (APS) is desirable. Likelihood ratios (LRs) with corresponding test-result intervals can identify the power of a test to discriminate between a diseased and nondiseased patient and may be useful for the semiquantitative interpretation of aCL/aβ2GPI results., Objectives: To determine moderate and high thresholds for aCL and aβ2GPI IgG/IgM measured with chemiluminescent immunoassay, enzyme-linked immunosorbent assay, fluorescence enzyme immunoassay, and multiplex flow immunoassay., Methods: aCL and aβ2GPI antibodies IgG/IgM were determined with 4 solid-phase systems in a case-control study population including 381 APS patients and 727 controls. Interval-specific LRs (IS-LR) were calculated for ranges determined by prespecified specificity and sensitivity levels. Three methods were used for determining thresholds that separated low, moderate, and high positive antibody levels. Interassay agreement was checked with Cohen's kappa statistics., Results: Assay- and antibody-specific thresholds demonstrated increasing IS-LR, reflecting different clinical significance for low, moderate, and high levels, especially for IgG aCL and aβ2GPI and in thrombotic APS. IS-LRs per antibody and unit range were comparable across solid-phase platforms resulting in enhanced harmonization of result interpretation. Agreement between assays for identifying high levels was improved by semiquantitative interpretation compared with that by quantitative reporting., Conclusion: aCL and aβ2GPI IgG/IgM moderate and high thresholds were determined for 4 analytical platforms. Thresholds improve harmonized interpretation of aCL/aβ2GPI levels across platforms. The proposed thresholds should be verified in an independent case-control study to check interlaboratory transferability., Competing Interests: Declaration of competing interests G.W.M. was employed at Guy’s and St. Thomas’ Hospitals at the time of sample collection and reports consultancy fees from Technoclone. The other authors have no competing interests to disclose., (Copyright © 2024 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)

This meta-analysis assesses antiphospholipid antibodies' (aPLs) impact on heart valve disease in Systemic Lupus Erythematosus (SLE) patients. We searched PubMed, Embase, Cochrane, and Web of Science up to January 2024 for comparative studies of heart valve disease in aPL-positive versus aPL-negative SLE patients. Fixed-effect or random-effect models were used to synthesize data, with I 2 and sensitivity analyses for heterogeneity and the trim-and-fill method for publication bias. Including 25 studies with 8089 patients, of which 919 had valvular changes, aPLs significantly increased the risk of heart valve disease (OR = 2.24, 95% CI: 1.58-3.18, p < 0.001). Lupus anticoagulant (LA) indicated the highest risk (OR = 4.90, 95% CI: 2.26-10.60, p < 0.001), anticardiolipin antibodies (aCL) doubled the risk (OR = 2.69, 95% CI: 1.47-4.93, p = 0.001), and anti-β2 glycoprotein I (aβ2GPI) showed a 70% increase (OR = 1.70, 95% CI: 1.17-2.45, p = 0.005). Valve-specific analysis indicated the mitral valve was most commonly involved (26.89%), with higher occurrences in aPL-positive patients (33.34% vs. 15.92%, p = 0.053). Aortic and tricuspid valve involvements were 13.11% vs. 5.42% (p = 0.147) and 12.03% vs. 8.52% (p = 0.039), respectively. Pulmonary valve disease was rare and similar across groups (1.01% in aPL-positive vs. 1.52% in aPL-negative). Significantly, only tricuspid valve disease showed increased risk in aPL-positive patients (OR = 2.66, 95% CI: 1.05-6.75, p = 0.039). APLs notably increase the risk of heart valve disease in SLE patients, with a pronounced effect on tricuspid valve involvement. Regular cardiac assessments for aPL-positive SLE patients are crucial for timely intervention and improved prognosis., (© 2024. The Author(s).)

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).

Antiphospholipid syndrome (APS) is a rare systemic autoimmune disease characterized by recurrent pregnancy morbidity or thrombosis in combination with the persistent presence of antiphospholipid antibodies (aPLs) in plasma/serum. Antiphospholipid antibodies are a heterogeneous, overlapping group of autoantibodies, of which anti-β2-glycoprotein I (aβ2GPI), anticardiolipin (aCL) antibodies and antibodies that prolong plasma clotting time in tests in vitro known as lupus anticoagulant (LAC) are included in the laboratory criteria for the diagnosis of APS. The presence of LAC antibodies in plasma is indirectly determined by measuring the length of coagulation in two tests - activated partial thromboplastin time (aPTT) and diluted Russell's viper venom time (dRVVT). The concentration of aβ2GPI and aCL (immunglobulin G (IgG) and immunoglobulin M (IgM) isotypes) in serum is directly determined by solid-phase immunoassays, either by enzyme-linked immunosorbent assay (ELISA), fluoroimmunoassay (FIA), immunochemiluminescence (CLIA) or multiplex flow immunoassay (MFIA). For patient safety, it is extremely important to control all three phases of laboratory testing, i.e. preanalytical, analytical and postanalytical phase. Specialists in laboratory medicine must be aware of interferences in all three phases of laboratory testing, in order to minimize these interferences. The aim of this review was to show the current pathophysiological aspects of APS, the importance of determining aPLs-a in plasma/serum, with an emphasis on possible interferences that should be taken into account when interpreting laboratory findings., Competing Interests: Potential conflict of interest None declared., (Copyright Croatian Society of Medical Biochemistry and Laboratory Medicine.)

Objectives: We conducted a comparison between the nonnormalized dilute Russell viper venom time (dRVVT) screen/confirm ratio (SCR) in patient plasma and the normalized SCR obtained using reference pooled plasma. The aim was to assess the impact of normalization on the lupus anticoagulant (LA) status in our patient population., Methods: In our retrospective analysis, we included a total of 464 patients who underwent dRVVT testing. For those with positive screens, mixing studies were performed, followed by confirmatory testing. Additionally, the dRVVT of reference pooled plasma was measured. A positive conventional (nonnormalized) or normalized SCR was defined as an SCR greater than or equal to 1.2., Results: In total, 5.6% (26) of the 464 samples tested were confirmed positive for LA by both methods, out of which 12 had a clinical history of thrombosis. Although a statistically significant difference between the 2 groups (P = .0096) was found, the magnitude of absolute mean SCR differences (bias) was 0.04 (2.51%). There was 100% concordance of testing results between the 2 groups., Conclusions: The lupus anticoagulant status by the dRVVT assay was not changed based on normalization. Normalization was of no clinical benefit in our patient population; therefore, there was no need for the extra calculation step. Normalization may be useful for intermethod and interlaboratory studies and not for within-method LA detection., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Introduction: Dilute Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT) are the mainstay assays in lupus anticoagulant (LA) detection yet they have limitations, particularly in relation to interferences and specificity. The recently validated Taipan snake venom time (TSVT) screening with ecarin time (ET) confirmatory assays overcome many of those limitations due to the innate specificity engendered from direct prothrombin activation, and insensitivity to the effects of vitamin K antagonists (VKA). The present study aimed to further evidence diagnostic utility of TSVT/ET by performing them in samples from 116 nonanticoagulated patients with established triple-positive antiphospholipid syndrome (APS)., Methods: Samples were identified in three expert centres who performed dRVVT, APTT and solid phase antiphospholipid antibody assays with reagents from a variety of manufacturers. All samples additionally received TSVT/ET analysis using standardised reagents., Results: Ninety seven of 116 (83.6%) were dRVVT- and APTT-positive, 85/97 (87.6%) of which were TSVT/ET-positive, 9/116 (7.8%) were dRVVT-positive only, 6 of which were TSVT/ET-positive, and 10/116 (8.6%) were APTT-positive only, 5 of which were TSVT/ET-positive. 96/116 TSVT/ET-positivity returned a high sensitivity for LA of 82.8%. Low coefficients of determination revealed weak relationships between LA potency and anticardiolipin and anti-β 2 -glycoprotein I antibody titres for all three LA assays., Conclusions: TSVT/ET has high sensitivity for the clinically significant LA found in triple positive APS patients. TSVT/ET can establish multiple LA assay positivity in nonanticoagulated patients negative for one of dRVVT or APTT, and is the only assay pairing insensitive to VKAs, the recommended anticoagulation for APS., (© 2024 John Wiley & Sons Ltd.)

Lupus anticoagulant-hypoprothrombinemia syndrome (LAHPS) is a rare, acquired coagulopathy syndrome. Here, we aim to summarize the clinical features of LAHPS to improve the understanding of the disease. The clinical data of 52 patients with LAHPS retrieved through PubMed from 2019 to 2023, supplemented with a local case of a child with LAHPS, were retrospectively analyzed, and the clinical characteristics were summarized. 56.6% of LAHPS patients were female, the median age at onset was 13.0 years (range, 1.2-85 years), and the median activity of factor II was 18.0% (range, 0.1-69%). 64.2% of LAHPS patients experienced hemorrhage, with 29.4% having multisite hemorrhage and 20.6% experiencing both nonsevere and severe hemorrhage. Most of the reported cases were secondary to autoimmune diseases (60.6%), followed by infections (33.3%). Corticosteroids were administered to 79.3% of patients with hemorrhage, and 90.6% of patients with LAHPS showed improvement. In conclusion, LAHPS is most commonly observed in female patients, particularly those under 18 years of age. LAHPS is characterized by hemorrhage, occurring at various sites and with varying degrees of severity, but the majority of patients improve with appropriate treatment and management., Competing Interests: None declared., (Thieme. All rights reserved.)

Acquired factor XI deficiencies due to factor-specific inhibitors are rare and may be associated with lupus anticoagulant. We report a 63-year-old male with suspected postsurgical bleeding, prior surgical site infection, an isolated prolonged activated partial thromboplastin time, and a positive lupus anticoagulant. Although the factor II assay was normal, factor VIII and IX assays initially demonstrated nonparallelism with factor activity that consistently increased to normal reference ranges with serial dilutions. A discrepancy in factor XI activity results was discovered when the in-house method demonstrated undetectable activity (<3%); send-out testing using different instrument/reagent combinations revealed the presence of factor XI activity between 70% and 76%. The patient received surgical follow-up and was subsequently discharged home. Given the differential in vitro inhibition of factor XI activity on our initial in-house testing, this case highlights the importance of recognizing factor assay interference in the presence of a known lupus anticoagulant inhibitor, with strategies to mitigate potentially erroneous results., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: To evaluate the effectiveness of the 2023 ACR/EULAR criteria for antiphospholipid syndrome (APS) in a Chinese cohort, and compare them with the Sapporo and revised Sapporo criteria., Methods: A cohort comprising 436 patients diagnosed with APS and 514 control subjects was enrolled, including 83 with seronegative APS and 86 classified as antiphospholipid antibody (aPL) carriers. We assessed IgG and IgM anticardiolipin antibodies (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies using ELISA, along with a systematic collection of lupus anticoagulant data. Subsequently, we compared the sensitivity and specificity across the three classification criteria., Results: The 2023 ACR/EULAR criteria exhibited improved specificity at 98 %, surpassing the revised Sapporo (90 %) and original Sapporo (91 %) criteria. However, this came with decreased sensitivity at 82 %, in contrast to higher sensitivities in the revised Sapporo (98 %) and Sapporo (91 %) criteria. Examining individual components sheds light on the scoring system's rationale within the new criteria. The inclusion of microvascular thrombosis, cardiac valve disease, and thrombocytopenia improved the identification of nine patients previously classified as "probable APS". Insufficient scoring in 78 previously diagnosed APS individuals was linked to traditional risk factor evaluations for thrombotic events, the emphasis on determining whether obstetric events are linked to severe preeclampsia (PEC) or placental insufficiency (PI), and the lower scores assigned to IgM aCL and/or aβ2GPI antibody. Seronegative APS remained a challenge, as non-criteria aPL and other methods were not included., Conclusions: The new criteria presented notable advancements in specificity. This study provides detailed insights into the strengths and possible challenges of the 2023 ACR/EULAR criteria, enhancing our understanding of their impact on clinical practice., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Coronavirus disease 2019 (COVID-19) is associated with coagulation abnormalities and increased risk for venous and arterial thrombi. This study aimed to evaluate D-dimer levels and lupus anticoagulant (LAC) positivity in pregnant individuals with and without Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection., Study Design: This was a prospective cohort study of pregnant individuals delivering at a single academic institution from April 2020 to March 2022. Individuals with a positive SARS-CoV-2 result during pregnancy were compared with a convenience sample of those without a positive SARS-CoV-2 result. For individuals with SARS-CoV-2 infection, severity was assessed based on the National Institutes of Health classification system. The primary outcome was D-dimer level measured during delivery admission. The secondary outcomes were LAC positivity and thromboembolic events. Outcomes were compared between individuals with and without a positive SARS-CoV-2 result, and further by disease severity., Results: Of 98 participants, 77 (78.6%) were SARS-CoV-2 positive during pregnancy. Among individuals with SARS-CoV-2 infection, severity was asymptomatic in 20 (26.0%), mild in 13 (16.9%), moderate in 4 (5.2%), severe in 38 (49.4%), and critical in 2 (2.6%). The D-dimer concentration at delivery did not significantly differ between those with a SARS-CoV-2 positive result compared with those without (mean 2.03 µg/mL [95% confidence interval {CI} 1.72-2.40] vs. 2.37 µg/mL [95% CI 1.65-3.40]; p  = 0.43). Three individuals (4%) with SARS-CoV-2 infection and none (0%) without infection were LAC positive ( p  = 0.59). There were no clinically apparent thromboses in either group. D-dimer concentrations and LAC positive results did not differ by COVID-19 severity., Conclusion: Thrombotic markers did not differ in pregnant individuals by SARS-CoV-2 infection; however, high rates of LAC positivity were detected., Key Points: · Thrombotic markers did not differ in pregnant individuals by SARS-CoV-2 infection.. · Higher than expected rates of LAC positivity were detected.. · There were no clinically apparent thromboses.., Competing Interests: C.C.Y. has authored a U.S. patent (patent no. 10,232,023 B2, “Methods for treatment of and prophylaxis against inflammatory disorders”) held by the University of Utah for the use of neonatal neutrophil extracellular traps (NET)-inhibitory factor, for which PEEL Therapeutics Inc. holds the exclusive license., (Thieme. All rights reserved.)

Background: The clinical relevance of different antiphospholipid antibody (aPL) profiles, including low level anticardiolipin (aCL) and anti-β 2 -glycoprotein-I (aβ 2 GPI) antibodies, is ill-defined in the pediatric population. Our purpose is to describe the demographic, clinical, and laboratory characteristics of aPL positive pediatric patients based on different aPL profiles., Findings: In this single center retrospective cohort study, based on the screening of our pediatric (age ≤ 18) rheumatology electronic medical records (2016-2022), we identified patients who had at least one "positive" aPL (lupus anticoagulant [LA], aCL IgG/M, or aβ 2 GPI IgG/M) result. Patients were grouped into high- (LA positive and/or aCL/aβ 2 GPI IgG/M > 40U [ELISA]) and low-risk (LA negative and aCL/aβ 2 GPI IgG/M 20-39U) aPL profiles; those with persistently positive aPL were descriptively analyzed for demographic and clinical characteristics. Of 57 included patients, 34 (59%) had initial high- and 23 (40%) had initial low-risk profiles. Based on subsequent aPL results available in 42/57 (74%) patients, 25/27 (93%) in the high-, and 7/15 (47%) in the low-risk groups remained still positive. Of these 32 patients with persistently positive aPL, moderate-to-large vessel or microvascular thrombosis occurred in nine (28%) patients with high-risk and in none with low-risk aPL profiles; non-thrombotic aPL-related manifestations were reported in 15 (47%) patients with persistent aPL positivity., Conclusion: An initial high-risk aPL profile was persistent in approximately 90% of our cohort, a third of whom had thrombosis, and half had non-thrombotic aPL manifestations. Our results underscore the need for a large-scale effort to better characterize aPL-related manifestations in pediatric patients with persistent high-risk aPL-profiles., (© 2024. The Author(s).)

Background: Lupus anticoagulant-hypoprothrombinemia syndrome (LAHPS) is a rare disease caused by acquired factor II (FII) deficiency and lupus anticoagulant. Patients with LAHPS typically present with thrombosis and bleeding. However, little information is available on the evaluation of coagulation potential in patients with LAHPS. We examined global coagulation potentials in patients with LAHPS during the clinical course in this study., Methods: Coagulation potentials in two pediatric patients with LAHPS were assessed by measuring clotting time (CT) and clot formation time using Ca 2+ -triggered rotational thromboelastometry (ROTEM), CT and maximum coagulation velocity using clot waveform analysis (CWA), and lag time and peak thrombin using the thrombin generation assay (TGA). The day of admission was defined as day 0., Results: In case 1, the bleeding symptoms disappeared by day 5. However, the TGA and CWA results were markedly lower than normal, although FII activity (FII:C) returned to within the normal range by day 14. In contrast, ROTEM revealed a recovery to near-normal levels (day 14). All coagulation parameters (day 80) were within normal ranges. In case 2, coagulation potential was severely depressed until day 12, although FII:C returned to normal levels. Bleeding symptoms disappeared on day 19, and the ROTEM data revealed that the parameters were close to the normal range. The coagulation parameters in all assays were normalized on day 75., Conclusions: Recovery of coagulation potential in patients with LAHPS was slower than the recovery of FII:C. Moreover, ROTEM appeared to be clinically useful for assessing coagulation potential in patients with LAHPS., (© 2024 Japan Pediatric Society.)

Background: Coronavirus disease 2019 (COVID-19) is a complex disease with many clinicopathological aspects, including abnormal immunothrombosis, and the full comprehension of its pathogenetic mechanisms is urgently required., Methods/results: By means of a multidisciplinary approach, we here report a catastrophic COVID-19 in a 44-year-old Philippine male patient, discovered lupus anticoagulant (LAC)-positive shortly before death, occurred 8 days after hospitalization in a clinical scenario refractory to standard high acuity care recalling Asherson's syndrome (catastrophic antiphospholipid syndrome)., Conclusion: A parallelism between this severe form of COVID-19 and Asherson's syndrome can be so drawn. Both the diseases in fact exhibit hypercytokinemia, thrombotic microangiopathy, disseminated intravascular coagulation and multiple organ failure, they show a relationship with viral infections, and they are burdened by a high mortality rate. A genetic predisposition to develop these two overlapping conditions may be supposed., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objective: The clinical relevance of antiphospholipid antibodies (aPLs) in COVID-19 is controversial. This study was undertaken to investigate the prevalence and prognostic value of conventional and nonconventional aPLs in patients with COVID-19., Methods: This was a multicenter, prospective observational study in a French cohort of patients hospitalized with suspected COVID-19., Results: Two hundred forty-nine patients were hospitalized with suspected COVID-19, in whom COVID-19 was confirmed in 154 and not confirmed in 95. We found a significant increase in lupus anticoagulant (LAC) positivity among patients with COVID-19 compared to patients without COVID-19 (60.9% versus 23.7%; P < 0.001), while prevalence of conventional aPLs (IgG and IgM anti-β 2 -glycoprotein I and IgG and IgM anticardiolipin isotypes) and nonconventional aPLs (IgA isotype of anticardiolipin, IgA isotype of anti-β 2 -glycoprotein I, IgG and IgM isotypes of anti-phosphatidylserine/prothrombin, and IgG and IgM isotypes of antiprothrombin) was low in both groups. Patients with COVID-19 who were positive for LAC, as compared to patients with COVID-19 who were negative for LAC, had higher levels of fibrinogen (median 6.0 gm/liter [interquartile range 5.0-7.0] versus 5.3 gm/liter [interquartile range 4.3-6.4]; P = 0.028) and C-reactive protein (CRP) (median 115.5 mg/liter [interquartile range 66.0-204.8] versus 91.8 mg/liter [interquartile range 27.0-155.1]; P = 0.019). Univariate analysis did not show any association between LAC positivity and higher risks of venous thromboembolism (VTE) (odds ratio 1.02 [95% confidence interval 0.44-2.43], P = 0.95) or in-hospital mortality (odds ratio 1.80 [95% confidence interval 0.70-5.05], P = 0.24). With and without adjustment for CRP level, age, and sex, Kaplan-Meier survival curves according to LAC positivity confirmed the absence of an association with VTE or in-hospital mortality (unadjusted P = 0.64 and P = 0.26, respectively; adjusted hazard ratio 1.13 [95% confidence interval 0.48-2.60] and 1.80 [95% confidence interval 0.67-5.01], respectively)., Conclusion: Patients with COVID-19 have an increased prevalence of LAC positivity associated with biologic markers of inflammation. However, LAC positivity at the time of hospital admission is not associated with VTE risk and/or in-hospital mortality., (© 2021, American College of Rheumatology.)

Background: Antiphospholipid syndrome (APS) is characterized by episodes of thrombosis, obstetric morbidity or both, associated with persistently positive antiphospholipid antibodies (aPL). Studying the profile of a rare disease in an admixed population is important as it can provide new insights for understanding an autoimmune disease. In this sense of miscegenation, Brazil is characterized by one of the most heterogeneous populations in the world, which is the result of five centuries of interethnic crosses of people from three continents. The objective of this study was to compare the clinical and laboratory characteristics of Brazilian vs. non-Brazilian primary antiphospholipid syndrome (PAPS) patients., Methods: We classified PAPS patients into 2 groups: Brazilian PAPS patients (BPAPS) and PAPS patients from other countries (non-BPAPS). They were compared regarding demographic characteristics, criteria and non-criteria APS manifestations, antiphospholipid antibody (aPL) profile, and the adjusted Global Antiphospholipid Syndrome Score (aGAPSS)., Results: We included 415 PAPS patients (88 [21%] BPAPS and 327 [79%] non-BPAPS). Brazilian patients were significantly younger, more frequently female, sedentary, obese, non-white, and had a higher frequency of livedo (25% vs. 10%, p < 0.001), cognitive dysfunction (21% vs. 8%, p = 0.001) and seizures (16% vs. 7%, p = 0.007), and a lower frequency of thrombocytopenia (9% vs. 18%, p = 0.037). Additionally, they were more frequently positive for lupus anticoagulant (87.5% vs. 74.6%, p = 0.01), and less frequently positive to anticardiolipin (46.6% vs. 73.7%, p < 0.001) and anti-ß2-glycoprotein-I (13.6% vs. 62.7%, p < 0.001) antibodies. Triple aPL positivity was also less frequent (8% vs. 41.6%, p < 0.001) in Brazilian patients. Median aGAPSS was lower in the Brazilian group (8 vs. 10, p < 0.0001). In the multivariate analysis, BPAPS patients still presented more frequently with livedo, cognitive dysfunction and sedentary lifestyle, and less frequently with thrombocytopenia and triple positivity to aPL. They were also less often white., Conclusions: Our study suggests a specific profile of PAPS in Brazil with higher frequency of selected non-criteria manifestations and lupus anticoagulant positivity. Lupus anticoagulant (not triple positivity) was the major aPL predictor of a classification criteria event., (© 2021. The Author(s).)

Antibodies to phospholipids (aPL) and associated proteins are a hallmark in the diagnosis of anti-phospholipid syndrome (APS). Those included in the classification criteria are the lupus anticoagulant (LA) and the IgG and IgM isotypes of anticardiolipin (aCL) and anti-beta-2 glycoprotein I (β2GPI) antibodies. Non-classification criteria markers such as autoantibodies that recognize the phosphatidylserine/prothrombin (aPS/PT) complex have been proposed as biomarkers for APS. Studies of aPS/PT antibodies have shown a strong correlation to clinical manifestations and LA. We aimed to study the value and the persistence of aPS/PT IgG and IgM antibodies in a cohort of consecutive patients with clinical suspicion of APS and their utility as thrombotic risk markers. Our study, with 103 patients, demonstrates that persistently positive results for aPS/PT IgG antibodies were significantly associated with APS classification, thrombosis, triple aPL positivity, LA positive result, and the Global APS Score (GAPSS) > than 9 points (p < 0.01, for each condition). On the other hand, no association was seen with pregnancy morbidity (p = 0.56) and SLE (p = 0.07). Persistence of aPS/PT antibodies, defined according to the current laboratory classification criteria, likely improves the diagnosis and clinical assessment of patients with APS., Competing Interests: SL-S, GN, CB, and MM are employed at Werfen, which sells autoantibody assays. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The editor AS has declared past collaborations with one of the authors RC., (Copyright © 2021 Egri, Bentow, Rubio, Norman, López-Sañudo, Mahler, Pérez-Isidro, Cervera, Viñas, Espinosa and Ruiz-Ortiz.)

Background: Patients positive for all three types of antiphospholipid antibodies (aPLs; triple positivity) have been identified for having a high risk for thrombotic events. However, the clinical significance of isolated lupus anticoagulant (LAC) positivity is debated., Objectives: To investigate the clinical relevance of isolated LAC., Methods: A total of 456 patients were enrolled in this study; 66 antiphospholipid syndrome patients and 390 control patients. The control group consisted of autoimmune patients ( n  = 91), patients with thrombosis but without aPLs ( n  = 127), and normal controls ( n  = 172). LAC, anticardiolipin (anti-CL), and anti-β2 glycoprotein I (anti-β2GPI) immunoglobulin G (IgG) and immunoglobulin M (IgM) were determined according to the International Society on Thrombosis and Haemostasis (ISTH) guidelines. Anti-CL and anti-β2GPI were measured by four different solid-phase platforms to overcome variability between test systems. The noncriteria IgA anti-CL and anti-β2GPI, antidomain I of β2GPI IgG, and antiphosphatidylserine/prothrombin antibodies (anti-PS/PT) IgG and IgM were detected according to the ISTH guidelines for solid-phase assays., Results: In total, 70 patients were positive for LAC, of which 44 were negative for both anti-β2GPI and anti-CL antibodies. We found that isolated LAC proved to be strongly associated with vascular thrombosis (odds ratio [OR]: 7.3; 95% confidence interval [CI]: 3.3-16.1), even better than triple-positive samples (OR: 4.3; 95% CI: 1.6-12.2). The titers of the anti-PS/PT IgG and IgM were significantly higher in triple-positivity samples compared with samples with isolated LAC positivity. The majority of single LAC positives were anti-PS/PT-negative. We observed that LAC positivity was weaker in isolated LAC-positive patients compared with LAC activity in triple-positive patients., Conclusion: Isolated LAC was highly associated with thrombosis. The presence of anti-PS/PT antibodies could not explain LAC positivity in isolated LAC. Isolated LAC showed a weaker LAC activity compared with triple-positive patients., Competing Interests: None declared., (Thieme. All rights reserved.)

Most of the knowledge in pediatric antiphospholipid syndrome (APS) is derived from studies performed on the adult population. As in adults, antiphospholipid antibodies (aPL) can contribute to thrombosis, especially cerebrovascular thrombosis, in neonates and children. Since aPL have the potential to cross the placental barrier, and since the pediatric population is prone to infections, re-testing for their positivity is essential to specify their role in cerebrovascular thrombosis.In this review, we aimed at assessing the prevalence of aPL, criteria or non-criteria, in neonatal and childhood ischemic stroke and sinovenous thrombosis trying to find an association between aPL and cerebrovascular thrombosis in the neonatal and pediatric population. Also, we looked into the effect of aPL and anticoagulants/antiplatelets on the long term neurological outcomes of affected neonates or children. The questions regarding the prevalence of aPL among pediatric patients with cerebrovascular thrombosis, the relationship between the titers of aPL and incidence and recurrence of cerebrovascular events, the predictability of the long term neurological outcomes, and the most optimal anticoagulation plan are still to be answered. However, it is crucial for clinicians to screen neonates and children with cerebrovascular thrombosis for aPL and confirm their presence if positive.

Background: Lupus anticoagulants (LA) are detected by prolongation of clotting times for dilute Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT) screening tests. Direct oral anticoagulants (DOACs) can interfere with both screening and confirmatory tests. The present study aimed to investigate the influence of direct factor Xa inhibitors (DiXaIs) on screen, confirm and mixing tests and establish a method for differentiation from other sample types., Materials and Methods: A total of 257 samples including nonanticoagulated LA positive, LA positive with DiXaIs, factor deficiency, FVIII inhibitors, warfarin and non-APS DiXaIs were tested. APTT reagents Cephen LS/Cephen and dRVVT reagents LA1/LA2 were used, respectively, to screen/confirm the study group. Index of circulating anticoagulant (ICA) was calculated from clotting times based on the following formula as ICA screening and ICA confirmation. ICA= (1:1 Mix sample - Normal pooled plasma) / Screen patient x 100. An ICA matrix was established which suggested the presence of a DiXaI when both ICA screening and confirmation were above the cut-off. When only ICA screening is elevated, LA is suspected., Results: Sensitivity and specificity of the ICA matrix were 52.2% and 92.8% for DiXaIs and 38.1% and 96.7% for LA in APTT, and 61.2% and 92.9% for DiXaIs and 22.2% and 88.4% for LA in dRVVT, respectively., Conclusion: The ICA matrix achieved high specificity with a lower apparent sensitivity for DiXaI samples comparatively to other devices but due only to less interferences: the matrix could contribute to differentiating DiXaIs from LA in samples where anticoagulation status is unknown., (© 2021 John Wiley & Sons Ltd.)

Coronavirus disease 2019 (COVID-19) is characterized by a procoagulant state that can lead to fatal thromboembolic events. Several studies have documented a high prevalence of lupus anticoagulant that may at least partially explain the procoagulant profile of COVID-19. However, the association between lupus anticoagulant and thrombotic complications in COVID-19 is controversial and no study has specifically evaluated the impact of lupus anticoagulant on mortality. The aim of our study was to investigate the association between lupus anticoagulant and mortality in a large group of 192 consecutive patients hospitalized for COVID-19. Lupus anticoagulant was found in 95 patients (49.5%). No difference in the percentage of patients with lupus anticoagulant was observed between 130 survivors and 62 non-survivors (47.7 versus 53,2%; p = 0.4745). When the combined outcome of death or need for mechanical ventilation in survivors was taken into account, the difference in the prevalence of patients with lupus anticoagulant between the patients with the combined outcome (n = 76) and survivors who did not require mechanical ventilation (n = 116) was not significant (52.6% versus 47.4%; p = 0.4806). In multivariate analysis predictors of mortality or need for mechanical ventilation in survivors were obesity, low oxygen saturation and elevated troponin levels measured on admission. In conclusion, our study did not show any association of lupus anticoagulant with mortality and with need for mechanical ventilation in survivors. The role of obesity, low SaO2 and elevated troponin levels as predictors of a worse prognosis in patients hospitalized for COVID-19 was confirmed., (© 2020. Springer Science+Business Media, LLC, part of Springer Nature.)

Background:  The mixing test is used to identify the pathway to follow-up testing and is also useful for the investigation of lupus anticoagulant (LA) positivity. "To completely correct" indicates clotting factor deficiency, while "to not correct" indicates the presence of a clotting factor inhibitor including LA. "Index of circulation anticoagulant" and/or "percent correction" is used to interpret the results of mixing studies, but it does not accurately differentiate factor inhibitors from LA., Aim:  To precisely differentiate hemophilia A (HA), HA with inhibitor (HA-inh), and LA using the clot waveform analysis (CWA)-based mixing test., Methods:  Plasma samples from HA, LA, and HA-inh including acquired HA were incubated with normal plasma in 9:1, 1:1, and 1:9 mix ratios. From activated partial thromboplastin time CWA at 0-minute (immediately) and 12-minute incubation, the ratios of CWA parameters at 12 minutes/0 minute (inhibitor index) were assessed., Results:  The inhibitor index values of CWA parameters obtained using the mixing test in a 1:1 ratio demonstrated a significant difference between HA-inh and LA but could not differentiate LA from HA-inh completely. Plasmas used for the mixing tests in 9:1 and 1:9 ratios were able to fully distinguish between HA-inh (>0.5 BU/mL) and LA. These indices significantly correlated with inhibitor titer below 40 BU/mL ( r  > 0.90), possibly estimating FVIII inhibitor titer from the inhibitor index. Plasmas in HA and LA could be distinguished by mixing in a 1:1 ratio at 0 minute (immediately)., Conclusion:  The inhibitor index from CWA-based mixing tests with a 12-minute incubation could differentiate among HA, HA-inh, and LA quickly., Competing Interests: N.S., K.O., M.S., and K.N. received research support from SEKISUI MEDICAL CO., LTD. M.S. and K.N. received honoraria from the same company. Y.O., T.K., and M.E. are employees of SEKISUI MEDICAL. N.S., K.O., M.S., K.N., Y.O., and T.K. possess the pending patent relating to CWA., (Thieme. All rights reserved.)

Factor V inhibitors are a rare cause of life-threatening bleeding. We present a case of an acquired factor V inhibitor likely caused by coronavirus disease 2019 infection. Bleeding was manifested by severe anemia requiring frequent red-cell transfusion, left psoas muscle hematoma, and left retroperitoneal cavity hematoma. Factor V activity was less than 1% and the factor V inhibitor titer was 31.6 Bethesda units. Severe acute respiratory syndrome coronavirus 2 RNA testing of the nasopharynx was positive 2 weeks before presentation and continued to be positive for 30 days. The patient failed treatment with intravenous immunoglobulin and dexamethasone. Three cycles of plasmapheresis with fresh frozen plasma replacement resulted in correction of the bleeding and laboratory coagulopathy. This is the first reported case of a factor V inhibitor in a coronavirus disease 2019 patient and suggests that plasmapheresis may be a successful treatment strategy., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: This study aimed to investigate the association of antiphospholipid antibodies (aPL) with clinical activity and renal pathological activity in patients with lupus nephritis (LN)., Methods: Levels of anticardiolipin () antibodies, anti-β2-glycoprotein I (anti-β2-GPI) antibodies and lupus anticoagulant (LAC) were measured, and other clinical and pathological data were also obtained during the same period before renal biopsy., Results: A total of 83 patients with LN were included in this study, 40 patients (48.2%) in the s positive group and 43 patients in the aPL negative group. LN patients with positive aPL had significantly higher SLEDAI (p = 0.012), more hematuria (p = 0.043), lower serum C3 (p = 0.003) and C4 (p = 0.014), and a higher pathological activity index (p = 0.012), more micro-thrombosis (p = 0.046) and more C3 deposits (p = 0.038) in the glomerulus than patients with negative aPL The level of IgG- was significantly correlated with SLEDAI and serum level of C3 (r = 0.44, p < 0.001; r = -0.39, p = 0.003, respectively). The level of IgM- was significantly correlated with SLEDAI, and serum levels of C3 and C4 (r = 0.27, p = 0.014; r = -0.22, p = 0.041; r = -0.23, p = 0.035, respectively)., Conclusions: Our work suggests that aPL, especially, are correlated with both clinical activity and renal pathological activity in patients with LN.

Objectives: Patients with APS are at increased risk of thromboembolism. Neutrophils have been shown to play a role in inducing thrombosis. We aimed to investigate differences in neutrophil subpopulations, their potential of activation and neutrophil extracellular trap (NET) formation comparing high and low-density neutrophils (HDNs/LDNs) as well as subpopulations in patients with APS and controls to gain deeper insight into their potential role in thrombotic manifestations in patients with APS., Methods: HDNs and LDNs of 20 patients with APS and 20 healthy donors were isolated by density gradient centrifugation and stimulated. Neutrophil subpopulations, their activation and NET release were assessed by flow cytometry., Results: LDNs of both groups showed higher baseline activation, lower response to stimulation (regulation of activation markers CD11b/CD66b), but higher NET formation compared with HDNs. In patients with APS, the absolute number of LDNs was higher compared with controls. HDNs of APS patients showed higher spontaneous activation [%CD11b high: median (interquartile range): 2.78% (0.58-10.24) vs 0.56% (0.19-1.37)] and response to stimulation with ionomycin compared with HDNs of healthy donors [%CD11b high: 98.20 (61.08-99.13) vs 35.50% (13.50-93.85)], whereas no difference was found in LDNs. NET formation was increased in patients' HDNs upon stimulation., Conclusion: HDNs and LDNs act differently, unstimulated and upon various stimulations in both healthy controls and APS patients. Differences in HDNs and LDNs between patients with APS and healthy controls indicate that neutrophils may enhance the risk of thrombosis in these patients and could thus be a target for prevention of thrombosis in APS., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Objective: The aim of the present study was to describe the demographic, clinical and immunological characteristics of patients with late-onset (≥50 years) SLE vs patients with early-onset SLE (<50 years)., Methods: We performed a cross-sectional retrospective study of 3619 patients from the RELESSER database (National Register of Patients with Systemic Lupus Erythematosus of the Spanish Society of Rheumatology)., Results: A total of 565 patients (15.6%) were classified as late-onset SLE and 3054 (84.4%) as early-onset SLE. The male-to-female ratio was 5:1. Mean (s.d.) age at diagnosis in the late-onset group was 57.4 (10.4) years. At diagnosis, patients with late-onset SLE had more comorbid conditions than patients with early-onset SLE; the most frequent was cardiovascular disease (P <0.005). Furthermore, diagnostic delay was longer in patients with late-onset SLE [45.3 (3.1) vs 28.1 (1.0); P <0.001]. Almost all patients with late-onset SLE (98.7%) were Caucasian. Compared with early-onset SLE and after adjustment for time since diagnosis, patients with late-onset SLE more frequently had serositis, major depression, thrombotic events, cardiac involvement and positive lupus anticoagulant values. They were also less frequently prescribed immunosuppressive agents. Mortality was greater in late-onset SLE (14.3% vs 4.7%; P <0.001)., Conclusion: Late-onset SLE is insidious, with unusual clinical manifestations that can lead to diagnostic errors. Clinical course is generally indolent. Compared with early-onset disease, activity is generally reduced and immunosuppressants are less commonly used. Long-term prospective studies are necessary to determine whether the causes of death are associated with clinical course or with age-associated comorbidities in this population., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Antiphospholipid antibodies (aPL) have been extensively reported in children, but investigations into thrombotic risks associated with aPL positivity in pediatric patients is scarce. Positive aPL are not uncommon in pediatric connective tissue diseases (CTD), but identification and management of these patients is challenging due to lack of validated criteria and a paucity of data. In this study, we identify potential additional risk factors for thrombosis in a unique cohort of pediatric aPL positive carriers., Methods: Retrospective chart review was performed on 491 pediatric patients with CTD seen in our institution from 2001 to 2019. Patients without persistently moderate to high titer aPL at least 12 weeks apart were excluded. Univariate analysis was performed to evaluate correlation between different risk factors and thrombotic events., Results: Seventy-one aPL positive children with underlying CTD are included in this cohort. The majority (87%) are female and of Hispanic ethnicity (56%). Mean age of the cohort at the diagnosis of connective tissue disease is 12.7 (SD 2.6) years, and mean age of first positive aPL is 13.3 (SD 2.5) years. Average length of follow-up is 4.3 (SD 2.5) years. Four (5.6%) patients experienced arterial thrombosis, and 11 (15.5%) had venous thrombosis. Fifty-seven (80.3%) patients did not have any thromboembolic events. Among traditional risk factors and signs of endothelial injury, only Raynaud's phenomena demonstrated significant association with arterial thrombosis (OR = 8.4, 95%CI 1.13-111, P = 0.039), and hypertension or anti-hypertensive use demonstrated significant association with venous thrombosis (OR = 8.387, 95%CI 1.2 - 94, P = 0.02)., Conclusion: Data from our cohort suggest that Raynaud's phenomenon is a potential predictor of arterial thrombosis while the presence of hypertension or anti-hypertensive medication use is a potential predictor of venous thrombosis in aPL positive pediatric carriers. Further studies investigating pediatric aPL profiles and risk factors for development of thrombosis are needed to help guide clinicians in caring for these challenging patients.

We herein report an unusual case of lupus with bleeding diathesis in a Chinese adolescent boy. In the presence of lupus anticoagulant and hypoprothrombinemia, the diagnosis of lupus anticoagulant-hypoprothrombinemia syndrome was made. He responded promptly to immunosuppressive agents and achieved disease remission., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Lupus anticoagulant hypoprothrombinemia syndrome (LAHPS) is a rare phenomenon that leads to concomitant thrombosis and hemorrhage in children with SLE. LAHPS in pediatric SLE (pSLE) has a protracted course requiring long-term immunosuppressive therapy. Due to the rarity of this syndrome and paucity of reported cases, there is lack of standardized management. We herewith report 5 children with pSLE with LAHPS. Methodology: We retrospectively reviewed clinical features, laboratory features, treatment and outcome for 5 children with lupus anticoagulant hypoprothrombinemia syndrome with SLE and a review of literature of similar cases published., Results: Mean age of presentation was 10.2 ± 2.38 years (mean ± SD) and female to male ratio was 4:1. All children presented with mild to severe bleeding manifestations like gum bleed, epistaxis, hematuria, menorrhagia and subarachnoid bleed. Coagulation profile revealed prolonged PT and aPTT, with low prothrombin levels and positive Lupus anticoagulant in all children. Mixing studies were characteristic in these children. On comparing laboratory parameters majority had low C3, C4 levels, ANA and anti-DsDNA antibody positivity and three children had anticardiolipin positivity. One child had lupus nephritis along with LAHPS at presentation. All responded well to steroids and supportive measures., Conclusion: High index of suspicion is needed when child with lupus presents with bleeding manifestations for early diagnosis and treatment.

Patients with COVID-19 are known to be at risk of developing both venous, arterial and microvascular thrombosis, due to an excessive immuno-thrombogenic response to the SARS-CoV-2 infection. Overlapping syndromes of COVID-19 associated coagulopathy with consumptive coagulopathy and microangiopathy can be seen in critically ill patients as well. Blood was collected from 12 Intensive Care Unit (ICU) patients with severe COVID-19 who were on either mechanical ventilation or on high flow oxygen with a PaO2/FiO2 ratio of <300 mmHg. Laboratory tests were performed for parameters of haemostasis, clot waveform analysis and anti-phospholipid antibodies. CWA parameters were raised with elevated aPTT median Min1 (clot velocity) 9.3%/s (IQR 7.1-9.9%/s), elevated PT median Min1 10.3%/s (IQR 7.1-11.1%/s), elevated aPTT median Min2 (clot acceleration) 1.5%/s 2 (IQR 1.0-1.6%/s 2 ), elevated PT median Min2 5.2%/s 2 (3.6-5.7%/s 2 ), elevated aPTT median Max2 (clot deceleration) 1.3%/s 2 (IQR 0.8-1.4%/s 2 ) elevated PT median Max2 3.8%/s 2 (IQR 2.6-4.2%/s 2 ), increased aPTT median Delta change (decreased light transmission due to increased clot formation) 87.8% (IQR 70.2-91.8%) and PT median Delta change 33.0%. This together with raised median Factor VIII levels of 262.5%, hyperfibrinogenemia (median fibrinogen levels 7.5 g/L), increased median von Willebrand factor antigen levels 320% and elevated median D-dimer levels 1.7 μg/dl support the diagnosis of COVID-19 associated coagulopathy. A lupus anticoagulant was present in 50% of patients. Our laboratory findings further support the view that severe SARS-CoV-2 infection is associated with a state of hypercoagulability.

A 32-year-old multiparous obese woman was referred to our center at 37 weeks of twin gestation. She was referred for birth planning following an accidentally discovered high international normalised ratio (INR) in routine preoperative labs. Her history was significant for recurrent pregnancy-associated deep venous thrombosis as well as two early pregnancy losses. Further work-up revealed transaminitis, mild splenomegaly and high lupus anticoagulant titre. A multidisciplinary team of physicians from the high-risk pregnancy, anaesthesiology, haematology, gastroenterology and hepatology departments put a management plan; it culminated into uncomplicated delivery of the patient by repeated caesarian section. The team was also able to figure out the cause of the patient's high INR that is associated with thrombophilia rather than haemophilia., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

The dual positivity (DP) and triple positivity (TP) concepts bypass the poor comparability of immune/clotting assay for the laboratory classification of antiphospholipid syndrome (APS). To evaluate intensity of immune/clotting assays and DP/TP through different clinical severity groups (CSG) as follows: (1) non-thrombotic asymptomatic carriers of aPL (N-THR), thrombotic primary APS (THR), deceased (D) for recurrent and fatal thrombosis. Activated partial thromboplastin time ratio (aPTTr), dilute Russell viper venom time ratio (DRVVTr), IgG/IgM anticardiolipin (aCL) and anti β-2-glycoprotein-I (aβ2GPI). Participants: 33 N-THR, 64 THR and 11 D. The frequency of DP and TP (DRVVTr or aPTTr partnered with respective IgG aCL or aβ2GPI) increased across CSG (p = 0.006 and p = 0.003); mean DRVVTr and IgG aCL/aβ2GPI were always greater in TP versus non-TP within each CSG and progressively increased across the CSG. The intensity of individual lupus anticoagulants partnered with their corresponding IgG aPL related to the frequency of multiple positivity throughout CSG suggesting that of intensity of immune/clotting assays and multiple positivity are the different faces of the same diagnostic coin in our thrombotic PAPS cohort.

Problem: Although not being recommended in guidelines, many physicians perform routine screening for thrombophilia in RM patients suspecting a higher prevalence in these patients. The aim of this study was to analyze the prevalence of inherited and acquired thrombophilia in a large cohort of RM patients., Method of Study: Within a multicenter case-control study, n = 820 RM patients and n = 141 controls were included. The prevalence of inherited and acquired thrombophilia including deficiency of protein C/S and antithrombin, elevation of factor VIII activity, APC resistance including mutation in the factor V Leiden gene, mutation in the prothrombin gene and antiphospholipid antibodies were assessed. Further, we performed a meta-analysis of the prevalence of thrombophilia in RM patients including studies between 01/2000 and 01/2020., Results: An antiphospholipid syndrome (APLS) was only present in RM patients. Increased factor VIII concentration was significantly more prevalent in controls (RM vs controls: 5.8% vs 11.0%). None of the other thrombophilia did differ significantly between RM patients and controls. The meta-analysis revealed no significant difference in the occurrence of these thrombophilia between RM patients and controls., Conclusion: The prevalence of inherited thrombophilia does not differ between RM patients and controls. When analyzing rare events like thrombophilia, a high number of patients are needed to obtain reliable results, which might explain contradictory findings in previous studies analyzing small cohorts of RM patients. Despite being less prevalent than previously described, we still recommend screening for APLS as it is associated with severe pregnancy complications., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: We aim to describe a rare case of a young patient with a catastrophic antiphospholipid syndrome (cAPS) who evolved to systemic lupus erythematosus (SLE).Methodology: Case report description., Case Report: A 15 years old girl came to the emergency department with acute peritonitis secondary to ischemic perforation of the sigmoid. Angiotomography was suggestive of a thrombotic occlusion of the upper mesenteric artery. Laboratory tests revealed a positive lupus anticoagulant and antinuclear antibodies. A cAPS diagnosis was determined based on more than three different sites of thrombosis (lung, kidney, spleen and sigmoid) in less than one week with a lupus anticoagulant. She was treated with intravenous methylprednisolone 1 mg/kg/day associated with intravenous heparin followed by intravenous immunoglobulin. She had a very good outcome with a total improvement and was discharged from the hospital after 2 months. After 12 weeks, the lupus anticoagulant remained positive. After two months, a systemic lupus erythematosus was diagnosed. She was treated with increasing dose of prednisone and azathioprine 100 mg/day and hydroxychloroquine were added to the treatment. After 2 weeks, she was asymptomatic. She is currently well, asymptomatic using hydroxychloroquine, azathioprine and warfarin., Conclusion: This article reports a very unusual presentation which is rarely reported and clinicians should be alert to the possibility that CAPS may be the presenting event for SLE patients, condition known in adults and should also be remembered in pediatric scenario.

Although still debated, post-operative modification of hemostasis seems to be less pronounced after laparoscopy compared to open surgery. Antiphospholipid antibodies might play a role in the post-operative thromboembolic risk, although their evaluation in surgical patients has never been performed. Post-operative modification of antiphospholipid antibodies could be related to the surgical approach (laparoscopic or open). In this prospective study, the authors statistically compared the pre-operative values and post-operative modification of antiphospholipid antibodies in two homogeneous groups of patients operated on by laparoscopic and open surgery. No statistical differences within each group and between the two groups were shown comparing mean values of pre-operative and post-operative antiphospholipid antibodies. In the open group, there was a significant difference between pre-operative and post-operative LAC means (P < 0.01). In the laparoscopic group, on the contrary, no significant change in LAC values between pre- and post-operative tests (P = 0.55) was observed. Since LAC could be related to coagulation disorders, this study seems to support that laparoscopic surgery might induce a less risk of post-operative thromboembolic disease.