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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The utility of the dilute prothrombin time in the interpretation of antiphospholipid syndrome testing

OBJECTIVES

To evaluate the utility of the dilute prothrombin time (DPT) in diagnosing antiphospholipid syndrome (APS), alone and when paired with the dilute Russell viper venom time (DRVVT).

METHODS

Dilute prothrombin time and DRVVT testing was performed on plasma samples spiked with apixaban or rivaroxaban, or depleted of vitamin K-dependent clotting factors. A retrospective analysis of all functional APS testing results over a 44-month period at the University of Chicago Medical Center was performed.

RESULTS

In spiking studies, the screening clotting time in the DPT (DPTS) is more sensitive to deficiency of vitamin K-dependent factors than is the screening clotting time in the DRVVT (DRVVTS). The converse is true for factor Xa direct oral anticoagulant (DOAC)-spiked plasma. In a 44-month retrospective analysis, only 2.6% of clinical APS panels showed isolated positivity in the DPT-based system. Comparing the DPT-based system with the DRVVT-based system showed utility in identifying false-positive DRVVT results due to anticoagulation. A DRVVTS/DPTS ratio of 0.785 or lower predicted an international normalized ratio of 1.5 or higher (sensitivity, 86.3%; specificity, 60.4%; likelihood ratio, 2.18). Conversely, a DRVVTS/DPTS ratio of 1.165 or higher was the optimal cutoff for predicting the identification of factor Xa DOAC (sensitivity, 61.8%; specificity, 77.8%; likelihood ratio, 2.78). Within the data set that had full DRVVT and DPT results, parameters were identified that could further improve identification of samples with anticoagulation interference.

CONCLUSIONS

Dilute prothrombin time lupus anticoagulant assay is rarely the sole laboratory functional evidence for APS, but when combined with the DRVVT, the DPT can serve as an effective screen for common anticoagulant interference.

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 (aβ2GPI) 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 aβ2GPI, 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.

Laboratory assessment of antiphospholipid syndrome: Laboratory data

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.

Primary antiphospholipid syndrome in a male presents with acute digital ischemia: Dramatic response to glucocorticoid

We present a rare case of primary antiphospholipid syndrome in a 38-year-old male who presented with painful digital ischemia. Early initiation of anticoagulation and addition of glucocorticoid led to a significant improvement in the patient.

Diagnosis and Management of Catastrophic Antiphospholipid Syndrome and the Potential Impact of the 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria

Catastrophic antiphospholipid syndrome (CAPS) is a rare and life-threatening condition characterized by the persistence of antiphospholipid antibodies and occurrence of multiple vascular occlusive events. CAPS currently remains a diagnostic challenge and requires urgent treatment. The diagnosis of CAPS is made difficult by classification criteria used as diagnostic criteria in clinical practice, knowledge derived from retrospective data and case reports, confounding clinical and biological features, and its rapid onset and mortality. The absence of prospective studies of CAPS limits the strength of evidence for guideline treatment protocols. This comprehensive review summarizes the current understanding of the disease, and discusses how the 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria impact the definition and therapeutic management of CAPS, which is considered the most severe form of APS. The correct integration of 2023 ACR/EULAR APS classification criteria is poised to facilitate CAPS diagnosis, particularly in critical situations, offering a promising avenue for improved outcomes.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Testing for the lupus anticoagulant: the good, the bad, and the ugly

Lupus anticoagulant (LA) represents 1 of the laboratory criteria for classification of patients as having definite antiphospholipid syndrome (APS). The other 2 laboratory criteria are anticardiolipin antibodies and anti-beta2-glycoprotein I antibodies. At least 1 of these antiphospholipid antibody (aPL) tests need to be positive, with evidence of persistence, together with evidence of at least 1 clinical criterion for APS, before a patient can be classified as having definite APS. LA and other aPL assays are also important for diagnosis or exclusion of APS, as well as for risk stratification, with triple-positive patients carrying the greatest risk. Whereas LA is identified through "uncalibrated" clot-based assays, the other aPL assays (anticardiolipin and anti-beta2-glycoprotein I antibodies) represent immunological assays, identified using calibrated solid-phase methods. Because LA is identified using clot-based assays, it is subject to considerable preanalytical and analytical issues that challenge accurate detection or exclusion of LA. In this narrative review, we take a look at the good, the bad, and the ugly of LA testing, primarily focusing on the last 10 years. Although harmonization of LA testing as a result of International Society on Thrombosis and Haemostasis guidance documents and other international activities has led to improvements in LA detection, many challenges remain. In particular, several anticoagulants, especially direct oral anticoagulants and also vitamin K antagonists, given as therapy to treat the pathophysiological consequences of aPL, especially thrombosis, interfere with LA assays and can generate false-positive or false-negative LA findings. Overcoming these diagnostic errors will require a multifaceted approach with clinicians and laboratories working together.

Damage measured by Damage Index for Antiphospholipid Syndrome (DIAPS) in antiphospholipid antibody-positive patients included in the APS ACTION registry

OBJECTIVES

Our primary objective was to quantify damage burden measured by Damage Index for Antiphospholipid Syndrome (DIAPS) in aPL-positive patients with or without a history of thrombosis in an international cohort (the APS ACTION cohort). Secondly, we aimed to identify clinical and laboratory characteristics associated with damage in aPL-positive patients.

METHODS

In this cross-sectional study, we analysed the baseline damage in aPL-positive patients with or without APS classification. We excluded patients with other autoimmune diseases. We analysed the demographic, clinical and laboratory characteristics based on two subgroups: (i) thrombotic APS patients with high vs low damage; and (ii) non-thrombotic aPL-positive patients with vs without damage.

RESULTS

Of the 826 aPL-positive patients included in the registry as of April 2020, 586 with no other systemic autoimmune diseases were included in the analysis (412 thrombotic and 174 non-thrombotic). In the thrombotic group, hyperlipidaemia (odds ratio [OR] 1.82; 95% CI 1.05, 3.15; adjusted P = 0.032), obesity (OR 2.14; 95% CI 1.23, 3.71; adjusted P = 0.007), aβ2GPI high titres (OR 2.33; 95% CI 1.36, 4.02; adjusted P = 0.002) and corticosteroid use (ever) (OR 3.73; 95% CI 1.80, 7.75; adjusted P < 0.001) were independently associated with high damage at baseline. In the non-thrombotic group, hypertension (OR 4.55; 95% CI 1.82, 11.35; adjusted P = 0.001) and hyperlipidaemia (OR 4.32; 95% CI 1.37, 13.65; adjusted P = 0.013) were independent predictors of damage at baseline; conversely, single aPL positivity was inversely correlated with damage (OR 0.24; 95% CI 0.075, 0.77; adjusted P = 0.016).

CONCLUSIONS

DIAPS indicates substantial damage in aPL-positive patients in the APS ACTION cohort. Selected traditional cardiovascular risk factors, steroids use and specific aPL profiles may help to identify patients more prone to present with a higher damage burden.

The lupus anticoagulant titer is associated with elevated antiphosphatidylserine/prothrombin immunoglobulin-M isotype antibody levels

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 (R2  = 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.

To normalize or not?: Dilute Russell viper venom time testing

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 association of an elevated Th/Ts ratio and lupus anticoagulant with symptomatic osteonecrosis in systemic lupus erythematosus patients

Objective

This study aimed to assess the risk factors for symptomatic osteonecrosis (ON) in systemic lupus erythematosus (SLE) and identify clinical characteristics and laboratory markers for predicting symptomatic ON occurrence in SLE patients.

Methods

Seventy (6.0%) of 1175 SLE patients diagnosed with symptomatic ON were included in this study. An equal number of SLE patients without symptomatic ON, matched in terms of age and gender, were enrolled in the control group. Clinical symptoms, routine laboratory examinations, lymphocyte subsets, and treatments of these patients were retrospectively reviewed and compared between the two groups. Logistic regression analysis was employed to identify risk factors associated with symptomatic ON in SLE.

Results

Among the 70 cases in the symptomatic ON group, 62 (88.6%) patients experienced femoral head necrosis, with bilateral involvement observed in 58 patients. Bone pain was reported in 32 cases (51.6%), and 19 cases (30.6%) presented with multiple symptoms. Univariate analysis revealed significant differences between the two groups in various factors, including disease duration (months), cumulative steroid exposure time, history of thrombosis, neurological involvement, the number of affected organs, myalgia/myasthenia, and the use of medications such as glucocorticoids, immunosuppressants, aspirin, and statins (P<0.05). Moreover, lupus anticoagulant (LA) levels were significantly higher in the symptomatic ON group than in the control group (P<0.05). Furthermore, notable distinctions were observed in peripheral blood immune cells, including an elevated white blood cell count (WBC), a decreased percentage of Ts cells (CD3+CD8+), and an elevated Th/Ts ratio. Logistic regression analysis revealed that a history of thrombosis, LA positivity, and an elevated Th/Ts ratio remained positive factors associated with symptomatic ON (P<0.05).

Conclusion

Decreased Ts cells and changes in the T lymphocyte subset play an important regulatory role in the development of symptomatic ON. A history of thrombosis and LA are associated with an increased probability of symptomatic ON in SLE and may serve as potential predictors.

Viewpoint: Lupus anticoagulant detection and interpretation in antiphospholipid syndrome

Lupus anticoagulant (LA) is a well-established risk factor for the clinical manifestations of antiphospholipid syndrome (APS). Accurate LA detection is an essential prerequisite for optimal diagnosis and management of patients with APS or aPL carriers. Variability remains a challenge in LA testing, with reliable detection influenced by multiple factors, including pre-analytical conditions, anticoagulation treatment, choice of tests and procedures performed, as well as interpretation of results, that can lead to false-positives or negatives. A standardised approach to LA testing, following current guidance, based on published data and international consensus, and with attention to detail, is required to underpin accurate detection of LA. Future work should focus on better characterisation of the nature of LA, which may ultimately lead to improved diagnosis and management of patients with APS and aPL carriers. This article reviews current practice and challenges, providing an overview on detection of LA.

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.

Case report on postoperative coagulation abnormalities

RATIONALE

Intracranial aneurysm (IA) is defined as a localized dilation of cerebral arteries. With the continuous development of modern medical technology, surgery is still one of the main treatment methods. Although there are various postoperative complications, abnormal coagulation function is rare, especially those caused by lupus antibodies after surgery. The patient not only experienced postoperative abnormalities in coagulation function, but also discovered the presence of lupus anticoagulants in their body. Is the patient suffering from coagulation dysfunction caused by lupus anticoagulants, how is lupus anticoagulant produced, and what's special about treatment. With these questions in mind, we reviewed the entire treatment process of the patient.

PATIENT CONCERNS

A 69-year-old woman presented with "headache and dizziness with neck pain" and was eventually diagnosed with IA hemorrhage. The patient underwent craniotomy under general anesthesia, and provided targeted support and treatment. Postoperative symptoms such as coma and intermittent fever occurred, and coagulation indicators were generally normal. After symptomatic support treatment, such as anti-infection treatment, the patient's temperature was gradually controlled. However, the abnormal clotting index and the efficacy of symptomatic therapeutic support, such as supplementation with coagulation factors, were not good. After further examination, the lupus anticoagulant was found, which provided us with a new treatment idea.

DIAGNOSES

Coagulation disorders, postoperative IA, hypertension grade 3 (extremely high risk), coronary atherosclerotic atheropathy, and type 2 diabetes.

INTERVENTIONS

The patient developed abnormal coagulation function after craniotomy, and symptomatic support treatment with coagulation factor supplementation and plasma infusion was ineffective. Finally, the lupus anticoagulant was found after a series of relevant examinations. After timely adjustment of the treatment plan, the patient's coagulation indices gradually improved.

OUTCOMES

In this report, we present the case of a patient with abnormal coagulation function caused by the lupus anticoagulant after IA surgery.

LESSONS

The coagulation function of the patient was abnormal after craniocerebral operation. After coagulation factor supplementation, the coagulation index of the patient was still not well improved. After further examination, the lupus anticoagulant was found. The treatment plan was actively adjusted, and the patient's condition gradually improved. Early recognition can allow doctors to provide appropriate therapy to patients.

Comparison of different algorithms for lupus anticoagulant detection: a single-center experience

Background

The laboratory tests for lupus anticoagulant (LA) detection comprise complex and multistep coagulation testing procedures. There is no established gold standard assay or direct comparison of algorithms as recommended by different guidelines.

Objectives

This study aimed to evaluate and compare the LA detection performance of different laboratory algorithms suggested by the existing guidelines.

Methods

The routine LA test data of 1801 plasma samples, including 188 LA-positive and 1613 LA-negative samples, were re-evaluated by applying the algorithms recommended by existing guidelines and were interpreted using various methods. Diagnostic performance indices for each LA detection algorithm were compared with those of the other algorithms. The efficacies of the different interpretation methods were analyzed to determine a suitable interpretation methodology for each assay.

Results

The diagnostic performance for detecting LA varied by the algorithm and method of interpretation used. All laboratory algorithms displayed exceptional diagnostic performance with all diagnostic parameters of >90.0%. Nearly perfect agreement was observed in all algorithms when compared to the Clinical and Laboratory Standards Institute 2014 guideline interpreted by normalized screen-to-confirm ratio (NSCR) and mixing test-specific cutoff (MTC), as a reference assay (Cohen's kappa coefficient, >0.90 [range, 0.94-1.00]). A combination of the index of circulating anticoagulant and NSCR was optimal for interpreting the activated partial thromboplastin time-based test, whereas a combination of the MTC and NSCR was suitable for the diluted Russell's viper venom time-based test.

Conclusion

All laboratory algorithms showed equivalent diagnostic performance. Establishing the best method of interpretation for each assay is recommended to improve LA detection performance.

Coagulation Testing in Real-World Setting: Insights From a Comprehensive Survey

The objective of this survey was to gain a real-world perspective on coagulation testing by evaluating the availability of various coagulation laboratory tests, assessing specific analytic and postanalytic steps in clinical laboratories in Korea.Participants were surveyed using a 65-question questionnaire specifically focused on their coagulation testing practices related to prothrombin time (PT), activated partial thromboplastin time (aPTT), plasma-mixing studies, lupus anticoagulant (LA) tests, platelet function tests, coagulation factor assays, and the composition of hemostasis and thrombosis test panels. The survey was performed between July and September 2022.The survey achieved a 77.9% (81 of 104) response rate. PT or aPTT tests were performed directly at all participating institutions, followed by D-dimer and fibrinogen tests, platelet function test, and plasma-mixing studies in order of frequency. Variations existed in the performance of mixing test and LA assessment. Patterns of coagulating testing differed depending on the size of the hospital. The survey revealed that most laboratories conducted coagulation tests following the international guidelines such as Clinical Laboratory Standards Institute guidelines and the Korean Laboratory Certification system. However, some coagulation tests, including mixing test and LA tests, are yet to be standardized in Korea.Continuous education on coagulation test methods and internal and external quality control are required to encourage laboratories to enhance the performance of coagulation testing.

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.

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

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

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Difficulties in laboratory diagnosis of coexistent lupus anticoagulant and factor VIII inhibitors: case report and review of literature

BACKGROUND

Whereas lupus anticoagulant (LA) and anti-factor VIII (anti-VIII) antibody are both acquired autoimmune coagulation inhibitors, they exhibit different pathophysiologic mechanisms and opposite clinical manifestations. Distinguishing between these two inhibitors is therefore essential for optimizing appropriate management. Harboring both antibodies, which is a rare condition, is of a challenging and confounding laboratory work-up.

CASE PRESENTATION

We illustrate a case report of a 39-year-old man admitted for the management of recurrent deep-vein thrombosis. Curiously, the initial physical examination revealed several hematoma and bruises of varying sizes. Biologically, a prolonged activated partial thromboplastin time (APTT) was objectified and was not corrected by the mixing study. The following detection of synchronous LA and anti-VIII was made using specific assays.

CONCLUSIONS

Through this case, we illustrate the complexity of diagnosing coexistent LA and FVIII inhibitors. In fact, the biological hallmark of both inhibitors is an isolated prolonged APTT that does not correct by the mixing study. Despite the progress in LA and anti-VIII assays and the ongoing updating of standardized recommendations, the lack of specific tests for LA and the limited availability of VIII quantification tests other than the clot-based assays make it difficult to distinguish adequately between the two inhibitors. Therefore, it is crucial to correlate test results with clinical features and patient evaluation.

Lupus Anticoagulant Detection under the Magnifying Glass

Diagnosis of antiphospholipid syndrome (APS) requires the presence of a clinical criterion (thrombosis and/or pregnancy morbidity), combined with persistently circulating antiphospholipid antibodies (aPL). Lupus anticoagulant (LA) is one of the three laboratory parameters (the others being antibodies to either cardiolipin or β2-glycoprotein I) that defines this rare but potentially devastating condition. For the search for aCL and aβ2-GP-I, traditionally measured with immunological solid-phase assays (ELISA), several different assays and detection techniques are currently available, thus making these tests relatively reliable and widespread. On the other hand, LA detection is based on functional coagulation procedures that are characterized by poor standardization, difficulties in interpreting the results, and interference by several drugs commonly used in the clinical settings in which LA search is appropriate. This article aims to review the current state of the art and the challenges that clinicians and laboratories incur in the detection of LA.

Anti-β2-glycoprotein I and anti-phosphatidylserine/prothrombin antibodies interfere with cleavage of factor V(a) by activated protein C

BACKGROUND

The acquired thrombotic risk factor known as lupus anticoagulant (LA) interferes with laboratory clotting assays and can be caused by autoantibodies against β2-glycoprotein I (β2GPI) and prothrombin. LA is associated with activated protein C (APC) resistance, which might contribute to thrombotic risk in patients with antiphospholipid syndrome. How antibodies against β2GPI and prothrombin cause APC resistance is currently unclear.

OBJECTIVES

To investigate how anti-β2GPI and antiphosphatidylserine/prothrombin (PS/PT) antibodies induce APC resistance.

METHODS

The effects of anti-β2GPI and anti-PS/PT antibodies on APC resistance were studied in plasma (of patients with antiphospholipid syndrome) and with purified coagulation factors and antibodies.

RESULTS

APC resistance was observed in LA-positive patients with anti-β2GPI or anti-PS/PT antibodies and in normal plasma spiked with monoclonal anti-β2GPI or anti-PS/PT antibodies with LA activity. Analysis of factor (F)V cleavage patterns after APC incubation indicated that anti-β2GPI antibodies attenuated APC-mediated FV cleavage at R506 and R306. APC-mediated cleavage at R506 is required for FV cofactor activity during inactivation of FVIIIa. Assays with purified coagulation factors confirmed that anti-β2GPI antibodies interfered with the cofactor function of FV during FVIIIa inactivation but not with FVa inactivation. Anti-PS/PT antibodies attenuated APC-mediated FVa and FVIIIa inactivation. Analysis of FV(a) cleavage patterns after APC incubation indicated that anti-PS/PT antibodies interfere with APC-mediated cleavage of FV at positions R506 and R306.

CONCLUSION

Anti-β2GPI antibodies with LA activity contribute to a procoagulant state by causing APC resistance via interference with the cofactor function of FV during FVIIIa inactivation. LA-causing anti-PS/PT antibodies interfere with the anticoagulant function of APC by preventing FV(a) cleavage.

Heparin induced thrombocytopenia in pregnancy: A therapeutic challenge case report and literature review

The anticoagulants of choice for the prevention and treatment of venous thromboembolic disease during pregnancy are unfractionated heparin and low-molecular-weight heparin. Heparin-induced thrombocytopenia (HIT) is introduced as a rare but critical side effect of heparin products raising the thromboembolic event paradoxically. Here, we present a case of HIT in pregnancy with challenging management due to coincidence of lupus anticoagulant (LA) and limited anticoagulant options in the pharmaceutical market of our country of residence. We describe a 6-week pregnant patient with deep venous thrombosis (DVT) and pulmonary thromboembolism (PTE), which developed HIT during antenatal care. Therapeutic anticoagulation was initiated with argatroban, then switched to apixaban due to limited access to argatroban. Another therapeutic challenge was the concurrent incidence of LA. The interdisciplinary care team decided on adding up warfarin and scheduled termination at 12 weeks regarding the hazardous condition of the patient. We also reviewed related case literature to convey a new insight into managing pregnancy-related HIT. HIT is a pro-coagulatory and lethal complication associated with heparin therapy that can be diagnosed by clinical suspicion, the 4T score system, and confirmatory laboratory analyses. Alternative anticoagulation is the cornerstone of the treatment and an interdisciplinary plan will be worthwhile to make the best clinical decision regarding the critical situation and least the thromboembolic events mortality during pregnancy.

Anti-Phosphatidylserine, Anti-Prothrombin, and Anti-Annexin V Autoantibodies in Antiphospholipid Syndrome: A Real-Life Study

The antiphospholipid antibodies (aPL) increase the risk of developing thrombotic events and may coexist with a variety of autoimmune diseases. They can be detected chronically or temporarily in patients with infectious diseases, during drug therapy, or in cases of cancer. A thrombotic event with aPL detection is known as antiphospholipid syndrome (APS) and the diagnostic criteria include the presence of lupus anticoagulant (LA), anticardiolipin (aCL) and β2-glycoprotein-1(aβ2GPI) antibodies. Other autoantigens recognized in APS are phosphatidylserine (aPS), prothrombin (aPT) and Annexin-5 (aA5). This real life study aimed to explore the connections between laboratory criteria and the prevalence of "non-criteria aPL" in APS. This study followed 300 patients with thrombosis and employed two phospholipid sensitivity assays for LA detection, chemiluminescence assays for aCL and aβ2GPI and enzyme-linked immunoassays for aPS, aPT and aA5. A significant association was found between aPS and aCL (r = 0.76) as well as aβ2GPI (r = 0.77), while the association with LA was less significant (r = 0.33). The results of the aPT and aA5 test did not correlate with criteria-antiphospholipid antibodies (r < 0.30). Since the risk of thrombotic complications increases with the intensity and the number of positive autoantibodies, measuring aPT and aA5 autoantibodies may be useful, particularly in aCL/aβ2GPI-negative patients or in cases of isolated LA positivity.

A Rare Rheumatologic Case of Catastrophic Antiphospholipid Syndrome

A very rare and severe disease catastrophic antiphospholipid syndrome is defined by small vessel occlusions resulting in multi-organ involvement in the presence of antiphospholipid antibodies. This case report presents a case of catastrophic antiphospholipid syndrome in a young female without past medical history.

Laboratory Diagnosis of Antiphospholipid Syndrome in Anticoagulated Patients

The laboratory diagnosis of antiphospholipid syndrome (APS) requires the measurement of solid-phase antibodies to cardiolipin or β2-Glycoprotein-I and the search for lupus anticoagulant (LA). The diagnosis of patients whilst on anticoagulation is impaired by the difficult interpretation of results, at least for LA, owing to the fact that prolongations of clotting times induced by LA superimpose those induced by anticoagulants. This is a matter of concern as treating physicians very often need to know the APS status of their patients to make a decision on secondary antithrombotic prophylaxis. This article aims to review the effect brought about by anticoagulants on APS diagnosis and discuss the options that can be used to overcome such an effect.

Patient with lupus anticoagulant caused aPTT prolongation corrected with prednisolone treatment and later anticoagulation treatment due to chronic atrial fibrillation

Key Clinical Message

Lupus anticoagulant caused aPTT prolongation in rare case can cause bleeding tendency especially when combined with other hemostasis abnormalities. In such cases, aPTT value can be corrected by immunosuppressants within several days of treatment. When anticoagulation therapy is needed vitamin K antagonist are a good option for the initial treatment.

Abstract

Lupus anticoagulant antibodies despite causing aPTT prolongation are commonly associated with increased risk of thrombosis. We present a rare case of patient when these autoantibodies resulted in dramatic aPTT prolongation and combined with associated thrombocytopenia resulted in minor bleeding events. In presented case treatment with oral steroids resulted in aPTT values correction followed by resolution of bleeding tendency within several days. Later, the patient developed chronic atrial fibrillation and was started on anticoagulation treatment initially with vitamin K antagonist without bleeding complications during follow-up period. Corresponding changes in patient's aPTT time in a course of whole treatment is presented.

Associations Among Antiphospholipid Antibody Types, Isotypes, and Titers: An AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION) Study

Several antiphospholipid antibody (aPL) profiles ("triple" and lupus anticoagulant [LA] positivity) are associated with a higher risk for clinical manifestations of antiphospholipid syndrome (APS). Further risk is correlated with higher levels of anticardiolipin antibody (aCL) and anti-β2 glycoprotein-I antibody (aβ2GPI), and with aPL persistence. Given that the 3 aPL tests detect partially overlapping sets of antibodies, the primary goal of this study was to characterize the associations among aPL tests using AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION) core laboratory data. The APS ACTION Registry includes annually followed adult patients with positive aPL based on the Revised Sapporo Classification Criteria. We analyzed baseline and prospective core laboratory data of the registry for associations among aPL tests using the Spearman rank correlation with Bonferroni-adjusted significance level for multiple comparisons. An aPL Load was calculated based on 6 tests (aCL IgG/IgM/IgA and aβ2GPI IgG/IgM/IgA); a receiver operating characteristic curve was used to evaluate the diagnostic performance of the aPL Load in predicting LA positivity. In 351 patients simultaneously tested for LA, aCL, and aβ2GPI, the frequency of moderate-to-high (≥40 U) titers of aCL and aβ2GPI IgG/IgM/IgA was higher in patients who were positive for LA vs those who were negative. An aPL Load was calculated for each patient to assess the overall aPL burden. For every 1-point increase in the aPL Load, the possibility of a positive LA test increased by 32% (odds ratio, 1.32; 95% CI, 1.2-1.5; P < .001). Based on core laboratory data from a large international registry, most aPL enzyme-linked immunosorbent assay ≥40 U and a high calculated aPL Load combining 6 aPL enzyme-linked immunosorbent assays were predictive of a positive LA. These data suggest that the combined quantitative burden of aPL may provide a mechanistic explanation of a positive LA.

Antiphospholipid Antibodies Occurrence in Acute SARS-CoV-2 Infection without Overt Thrombosis

We sought to determine the prevalence of antiphospholipid antibodies (aPLs) and their correlation with COVID-19 severity (in terms of clinical and laboratory parameters) in patients without thrombotic events during the early phase of infection. This was a cross-sectional study with the inclusion of hospitalized COVID-19 patients from a single department during the COVID-19 pandemic (April 2020-May 2021). Previous known immune disease or thrombophilia along with long-term anticoagulation and patients with overt arterial or venous thrombosis during SARS-CoV-2 infection were excluded. In all cases, data on four criteria for aPL were collected, namely lupus anticoagulant (LA), IgM and IgG anticardiolipin antibodies (aCL), as well as IgG anti-β2 glycoprotein I antibodies (aβ2GPI). One hundred and seventy-nine COVID-19 patients were included, with a mean age of 59.6 (14.5) years and a sex ratio of 0.8 male: female. LA was positive in 41.9%, while it was strongly positive in 4.5%; aCL IgM was found in 9.5%, aCL IgG in 4.5%, and aβ2GPI IgG in 1.7% of the sera tested. Clinical correlation: LA was more frequently expressed in severe COVID-19 cases than in moderate or mild cases (p = 0.027). Laboratory correlation: In univariate analysis, LA levels were correlated with D-dimer (p = 0.016), aPTT (p = 0.001), ferritin (p = 0.012), C-reactive protein (CRP) (p = 0.027), lymphocyte (p = 0.040), and platelet (p < 0.001) counts. However, in the multivariate analysis, only the CRP levels correlated with LA positivity: OR (95% CI) 1.008 (1.001-1.016), p = 0.042. LA was the most common aPL identified in the acute phase of COVID-19 and was correlated with infection severity in patients without overt thrombosis.

Heart Valve Involvement in Patients with Antiphospholipid Syndrome: A Long-Term Follow-Up Study of a Single Centre

BACKGROUND

Valve involvement is the most common cardiac manifestation in antiphospholipid syndrome (APS). The objective of the study was to describe the prevalence, clinical and laboratory features, and evolution of APS patients with heart valve involvement.

METHODS

A retrospective longitudinal and observational study of all APS patients followed by a single centre with at least one transthoracic echocardiographic study.

RESULTS

144 APS patients, 72 (50%) of them with valvular involvement. Forty-eight (67%) had primary APS, and 22 (30%) were associated with systemic lupus erythematosus (SLE). Mitral valve thickening was the most frequent valve involvement present in 52 (72%) patients, followed by mitral regurgitation in 49 (68%), and tricuspid regurgitation in 29 (40%) patients. Female sex (83% vs. 64%; p = 0.013), arterial hypertension (47% vs. 29%; p = 0.025), arterial thrombosis at APS diagnosis (53% vs. 33%; p = 0.028), stroke (38% vs. 21%; p = 0.043), livedo reticularis (15% vs. 3%; p = 0.017), and lupus anticoagulant (83% vs. 65%; p = 0.021) were more prevalent in those with valvular involvement. Venous thrombosis was less frequent (32% vs. 50%; p = 0.042). The valve involvement group suffered from higher mortality (12% vs. 1%; p = 0.017). Most of these differences were maintained when we compared patients with moderate-to-severe valve involvement (n = 36) and those with no or mild involvement (n = 108).

CONCLUSIONS

Heart valve disease is a frequent manifestation in our cohort of APS patients and is associated with demographic, clinical and laboratory features, and increased mortality. More studies are needed, but our results suggest that there may be a subgroup of APS patients with moderate-to-severe valve involvement with its own characteristics that differs from the rest of the patients with mild valve involvement or without valve involvement.

Lupus anticoagulants as a prospective independent predictor in COVID-19 patients

OBJECTIVE

Lupus anticoagulant (LA) are commonly detected during SARS-CoV-2 infection. However, the relationship between LA and clinical significance is still unclear.

METHODS

A retrospective chart analysis was performed on COVID-19 patients who were tested for LA at our hospital from March 2020 to November 2021. We analyzed the patient's characteristics based on the result of the LA test. In addition, subgroup analysis performed the LA-positive group who had undergone serial LA tests.

RESULTS

A total of 219 COVID-19 patients were enrolled in the study, 148 patients (67.6%) were positive for LA test. The LA-positive group received more treatment of high flow nasal cannula (LA-positive 73.0%, LA-negative 57.7%, p = 0.024). The LA-positive group showed prolonged aPTT, higher levels of CRP and fibrinogen (all p's < 0.05). Among 148 LA-positive patients, 127 patients (86.5%) were found to be LA-positive within 10 days of SARS-CoV-2 positive, and LA-positive group confirmed a median time to LA loss of 10 days. However, there was a group that was negative for LA in the early stages of infection and became positive about 13 days later. A subgroup analysis showed that these patients had different characteristics due to their longer hospital stays and higher D-dimer levels.

CONCLUSIONS

In COVID-19 patients, LA is expected to be associated to disease severity. Since the clinical significance of LA is different depending on the onset time of LA positivity, the LA test is suggested to be done at diagnosis of SARS-CoV-2 infection, even if LA is negative, follow-up test should be considered within 10 days.

Demographic, Clinical, and Serological Characteristics of Antiphospholipid Syndrome Patients From the Anticoagulation Clinic of Hospital Universitario San Vicente Fundación, Medellín, Colombia

INTRODUCTION

Antiphospholipid syndrome (APS) is an acquired autoimmune thrombophilia, characterized by vascular thrombosis or obstetric compromise, associated with the presence of antiphospholipid antibodies. Large international studies have analyzed the clinical/serological behavior of the disease and in Colombia, there are few cohorts that have been evaluated.

OBJECTIVE

The main objective is to characterize the patients with APS followed in the anticoagulation clinic of a tertiary care hospital and to determine the clinical manifestations and serological findings at diagnosis.

MATERIALS AND METHODS

A retrospective descriptive study was carried out to evaluate patients with a presumptive and/or confirmed diagnosis of APS, according to modified Sapporo criteria, which fulfilled the inclusion and exclusion criteria established by the authors. The information was collected from the review of medical records.

RESULTS

We included 103 patients, with the female sex being the most prevalent (86.6%). 54.3% of the patients (n = 56) had a diagnosis of primary APS. Venous thrombotic events occurred in 87.3% (n = 90) of the patients, 34.9% (n = 36) had arterial thrombosis (n = 36), and 3.9% (n = 4) had catastrophic APS (n = 4). 15 cases of Obstetric APS were documented. Lupus coagulation inhibitor (LA) positivity was the most prevalent marker in 84% (n = 68) of cases.

CONCLUSIONS

The clinical behavior in this cohort of patients is like that found in large international and national studies. Most patients have a probable diagnosis of APS, so they could overestimate the real prevalence and condition of long-term anticoagulant treatment.

The impact of antiphospholipid antibodies in Takayasu arteritis

BACKGROUND

The significance of antiphospholipid antibodies (aPL) is controversial in Takayasu arteritis (TA). This study was conducted to explore the frequency of aPL and their association with disease-related complications in TA.

METHODS

: This cross-sectional study was conducted to investigate the presence of anti-cardiolipin (aCL), anti-beta 2 glycoprotein- 1(aβ2G1) antibodies, and lupus anticoagulant (LA) in TA patients. TA patients admitted to the Department of Rheumatology of Hacettepe University Faculty of Medicine between December 2015 and September 2016 who fulfilled the American College of Rheumatology (ACR) classification criteria for TA were consecutively enrolled in the study. Patients were grouped according to aPL positivity and compared in terms of disease manifestations, type of vascular involvement at diagnosis, and vascular complications/interventions attributable to TA.

RESULTS

Fifty-three TA (49 female) patients were enrolled in the study. We detected 9 (16.9%) patients with IgM and/or IgG aβ2G1 and/or LA positivity. There were no patients with positive aCL. All aβ2G1 titers were low. There were no differences in terms of symptoms, signs, type of vascular involvement, the number of patients with disease-related complications or vascular interventions/surgery between aPL (+) and aPL(-) groups (p > 0.05 for all). The number of patients with thrombotic lesions was similar between the groups (p > 0.05). There were no patients with a history of venous thrombosis or on anticoagulant treatment in the aPL(+) group. Only 1 patient with IgM aβ2G1 (+) had a history of pregnancy loss.

DISCUSSION

Our results indicate that aPL positivity is not rare in TA. On the other hand, all aPL titers were low and no differences were found in the frequency of disease-related complications between aPL(+) and aPL(-) patient groups. Only TA patients with atypical manifestations with high suspicion of aPL-related complications should be considered to be investigated for aPL.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Performance characteristics of 5 numerical indexes in mixing test interpretation under coexistence of lupus anticoagulant and coagulation factor deficiency

Background

The mixing test is useful to investigate the cause of unexpectedly prolonged activated partial thromboplastin time (APTT). Several indexes are available for distinguishing correction from non-correction (ie, factor deficiency from inhibitors), but their performance characteristics may differ because of their different formulas. Furthermore, it is unclear how each index performs under the coexistence of factor deficiency and inhibitors.

Objectives

The objective of this study was to examine the differences in indexes, depending on factor VIII activity (FVIII:C) levels and lupus anticoagulant (LA) titers in test samples.

Methods

APTT was measured in spiked samples with various FVIII:C levels and LA titers, normal pooled plasma (NPP), and their 4:1, 1:1, and 1:4 mixtures. The following 5 indexes were calculated: index of circulating anticoagulant, mixing test normalized ratio, 4:1 and 1:1 percent corrections, and an APTT difference between the 1:1 mixture and NPP. The samples with LA, showing correction, were measured for FVIII:C in a one-stage assay to check parallelism.

Results

All indexes showed correction under FVIII deficiency and non-correction under higher LA titers. However, under lower LA titers, some indexes showed non-correction but others showed correction because of dilution effects and variations in formulas and/or sample mix ratios. The differences among the indexes were more pronounced under coexistent FVIII deficiency and LA, even though LA titers were equal in the tested samples; samples with lower FVIII:C showed correction, whereas those with normal FVIII:C showed non-correction. The samples tested for FVIII:C showed non-parallelism.

Conclusion

Each index had different performance characteristics to LA samples, which were pronounced under low FVIII:C levels in test samples.

Lupus Anticoagulant Is Associated with Critical Cases and High Mortality in COVID-19: A Literature Review

Background

In severe COVID-19 cases, a hypercoagulable state may occur. Antiphospholipid syndrome-related auto-antibodies (APSRAs) contribute to coagulopathy, but their role in COVID- 19 remains unclear. We aimed to investigate the prevalence of positive APSRAs and their effect on clinical outcomes in confirmed COVID-19 patients.

Materials and Methods

In this cross-sectional study, severe hospitalized COVID-19 cases were enrolled. Demographic and clinical data were obtained from the day of admission. APSRAs including IgG and/or IgM anticardiolipin (aCL) and anti-β2-glycoprotein1 (anti-β2GP1) as well as lupus anticoagulant (LAC) were measured.

Results

In this study, 54 severe COVID-19 cases with positive RT-PCR and chest CT scans were recruited. Positive APSRAs were found in 7 (12.9%) patients. Positive LAC was a more prevalent marker as compared to other tests (11.1%). The prevalence of positive aCL (IgM or IgG) and anti-ß2 GPI (IgM or IgG) was 1.8% (in an elderly woman). Lower oxygen saturation was found in the positive APSRAs group as opposed to the negative APSRAs group (70.3±9 vs. 84.8±9.7%). The mortality rate in the positive APSRAs group was significantly higher relative to the negative APSRAs group (83.3% vs. 27.1%; P-value: 0.01). Likewise, the mechanical ventilation requirement in the positive group was also higher (50% vs. 27.1%, P-value: 0.28).

Conclusion

This study indicated that LAC might be associated with critical cases and high mortality of COVID-19. Nonetheless, the mortality was not related to macrothrombotic incidence.

Routine Lupus Anticoagulant Sensitive aPTT Testing Can Prevent Unnecessary LA Testing

Even though routine screening of the general hospital population is discouraged, medical laboratories may use a "lupus sensitive" activated partial thromboplastin time test (aPTT) with phospholipid concentrations that are susceptible to inhibition by lupus anticoagulant (LA), to screen for the presence of LA. If deemed necessary, follow-up testing according to ISTH guidelines may be performed. However, LA testing is a laborious and time-consuming effort that is often not readily available due to a lack of automation and/or temporary unavailability of experienced staff. In contrast, the aPTT is a fully automated test that is available 24/7 in almost all medical laboratories and is easily interpreted with the use of reference ranges. In addition to clinical signs, the result of an LA sensitive aPTT may thus be used to lower the suspicion of the presence of LA and reduce costly follow-up testing. In this study, we show that a normal LA sensitive aPTT result may be safely used to refrain from LA testing in the absence of strong clinical suspicion.

A rare case of schizophrenia coexistence with antiphospholipid syndrome, β-thalassemia, and monoclonal gammopathy of undetermined significance

A patient with schizophrenia who was treated with chlorpromazine developed lupus anticoagulant (LA) and antiphospholipid syndrome (APS). On protein electrophoresis, a monoclonal immunoglobulin A peak was seen in this patient, defining a condition of monoclonal gammopathy of undetermined significance. Additionally, β-thalassemia was diagnosed with the CD41-42 genotype. This condition is extremely rare, particularly in patients with schizophrenia and APS. We present a case of a patient with schizophrenia and secondary APS who had a positive LA, a significantly prolonged activated partial thromboplastin time, endogenous coagulation factor deficiency and inhibitor, no bleeding, and an unexpected finding of β-thalassemia and monoclonal IgA. Following that, a literature review on the disorders was presented.

A Comparative Analysis of Anticardiolipin, Anti-Β2-Glycoprotein-1, and Lupus Anticoagulants in Saudi Women with Recurrent Spontaneous Abortions

Association and pathogenesis of antiphospholipid antibodies (APAs) in patients with Antiphospholipid syndrome (APS) as well as systemic lupus erythematosus (SLE) suffering from unexplained spontaneous abortions is controversial. Moreover, the majority of the published evidence is based on the patient histories rather than the study groups. The main objective of the present study is to do a comparative analysis of the high levels of antiphospholipid antibodies (APAs) including anticardiolipin (ACA), anti-β2-glycoprotein-1 (β2 GP1), and Lupus anticoagulants (LA) and their association with the gestational age of abortion and duration past abortion in Saudi women. In this study, 100 women living in Makkah city, located in the Western region of Saudi Arabia, with a mean age of 30.5 ± 12.60 years (mean ± standard deviation), having a previous history of recurrent spontaneous abortions were enrolled as case group and 100 healthy pregnant women previously having one or more successful pregnancies were selected as control group. Based on the gestational age of the patient’s miscarriages, our results revealed consistently and significantly high levels of ACA, β2 GP1, and LA, being greatest at more than 15 weeks when compared with 10 weeks and 11−15 weeks, respectively. Based on duration of past miscarriages, a slightly increased level was observed at ≤4 years after their first miscarriage. In addition, less or more equal levels of these antibodies were observed at 5−12 and more than 12 years in all the cases of miscarriages. We concluded an elevated pattern of APAs in these patients with an increase in the age of abortion. A comparison between the levels of ACA, β2 GP1, and LA further indicated a highly significant level of LA in all the cases of abortions (p < 0.0005).

A Patient with Severe Fever with Thrombocytopenia Syndrome, Activated Partial Thromboplastin Time Prolongation, and Transient Antiphospholipid Antibodies

A prolonged activated partial thromboplastin time (APTT) is observed in patients with severe fever with thrombocytopenia syndrome (SFTS) and is one of the risk factors for severe disease. The mechanism underlying a prolonged APTT is largely unknown. The presence of antiphospholipid (aPL) antibodies in various viral infections has been documented but never reported in a patient with SFTS. We herein report the first SFTS patient with APTT prolongation and concurrent transiently positive aPL antibodies (lupus anticoagulants and anticardiolipin antibodies) with no coagulation factor deficiency.

Diagnostic Challenges in Pulmonary Embolism in Young Adults: Thrombosis Associated With Cytomegalovirus and Mycoplasma pneumoniae

A 23-year-old man presented with a fever, shaking chills, headaches, nausea, and a dry cough. Investigations showed lymphocytic leukocytosis with atypical lymphocytes in a blood smear. Liver function test results, D-dimer concentrations, and fibrin degradation product concentrations were greatly elevated. Computed tomography of the whole body with contrast showed hepatosplenomegaly with splenic infarction and bilateral pulmonary embolism without deep vein thrombosis. Cytomegalovirus (CMV) immunoglobulin M, and serum CMV pp65 antigenemia were positive, and serum Mycoplasma pneumoniae (M. pneumoniae) antibody was also highly positive. These results suggested the diagnosis of co-infection of CMV and M. pneumoniae complicated by systemic arteriovenous thrombosis, which resulted in pulmonary embolism and splenic infarction. After he started edoxaban tosilate hydrate for the thrombosis, his symptoms resolved in a few days. To the best of our knowledge, this is the first case of co-infection of CMV and M. pneumoniae leading to pulmonary embolism and splenic infarction.

Severe Thrombocytopenia, Thrombosis and Anti-PF4 Antibody after Pfizer-BioNTech COVID-19 mRNA Vaccine Booster-Is It Vaccine-Induced Immune Thrombotic Thrombocytopenia?

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a serious and life-threatening complication occurring after adenovirus-vector COVID-19 vaccines, and is rarely reported after other vaccine types. Herein, we report a case of possible VITT after the Pfizer-BioNTech mRNA vaccine booster, who presented with extensive lower limb deep vein thrombosis, severe thrombocytopenia, markedly elevated D-dimer and positive anti-PF4 antibody occurring 2 weeks post-vaccination, concurrent with a lupus anticoagulant. A complete recovery was made after intravenous immunoglobulin, prednisolone and anticoagulation with the oral direct Xa inhibitor rivaroxaban. The presenting features of VITT may overlap with those of antiphospholipid syndrome associated with anti-PF4 and immune thrombocytopenia. We discuss the diagnostic considerations in VITT and highlight the challenges of performing VITT confirmatory assays in non-specialized settings. The set of five diagnostic criteria for VITT is a useful tool for guiding initial management, but may potentially include patients without VITT. The bleeding risks of severe thrombocytopenia in the face of thrombosis, requiring anticoagulant therapy, present a clinical challenge, but early recognition and management can potentially lead to favorable outcomes.

Autoimmune Diseases Affecting Hemostasis: A Narrative Review

Hemostasis reflects a homeostatic mechanism that aims to balance out pro-coagulant and anti-coagulant forces to maintain blood flow within the circulation. Simplistically, a relative excess of procoagulant forces can lead to thrombosis, and a relative excess of anticoagulant forces can lead to bleeding. There are a wide variety of congenital disorders associated with bleeding or thrombosis. In addition, there exist a vast array of autoimmune diseases that can also lead to either bleeding or thrombosis. For example, autoantibodies generated against clotting factors can lead to bleeding, of which acquired hemophilia A is the most common. As another example, autoimmune-mediated antibodies against phospholipids can generate a prothrombotic milieu in a condition known as antiphospholipid (antibody) syndrome (APS). Moreover, there exist various autoimmunity promoting environments that can lead to a variety of antibodies that affect hemostasis. Coronavirus disease 2019 (COVID-19) represents perhaps the contemporary example of such a state, with potential development of a kaleidoscope of such antibodies that primarily drive thrombosis, but may also lead to bleeding on rarer occasions. We provide here a narrative review to discuss the interaction between various autoimmune diseases and hemostasis.

Central Retinal Vein Occlusion Presumably Associated with Lupus Anticoagulant Induced by SARSCoV-2

PURPOSE

To report a case of unilateral central retinal vein occlusion (CRVO) and macular edema presumably associated with lupus anticoagulant (LA) induced by severe acute respiratory syndrome coronavirus 2 (SARS CoV-2).

METHOD

Case report.

RESULTS

A 32-year-old male patient presented to the emergency department with a 5-day history of blurry vision. He was diagnosed with a CRVO and macular edema. The only pathological finding was positive LA which could have been induced by his recent confirmed SARS CoV-2 infection. The patient's evolution was satisfactory after two injections of Intravitreal dexamethasone (Ozurdex®), with improvement in macular edema and visual acuity.

CONCLUSION

COVID-19 may be associated to retinal vascular occlusive disorders. Transient virus-induced LA might play a role in the pathogenesis of the thrombotic event.

Antiphospholipid syndrome in patients over 65 years: A comparative study of clinical and biological features and thrombotic relapses

OBJECTIVE

The aim of the study was to describe clinical and biological characteristics and thrombotic relapses of patients diagnosed with antiphospholipid syndrome (APS) after the age of 65 years, in comparison with patients diagnosed with APS before 65.

METHODS

This retrospective multicenter study was performed to 2005 from 2017 and included patients diagnosed with APS after the age of 65 years, in accordance with Sydney criteria. We compared these patients with APS patients diagnosed before the age of 65 years, and with control thrombotic patients older than 65 years.

RESULTS

Fifty-eight APS patients over the age of 65 years were compared to 127 APS patients aged less than 65 and to 58 controls. In elderly APS versus younger APS, there was a male predominance (58.6% vs 36.2% p = .001); myocardial infarction and lower limb deep vein thrombosis (LLDVT) were more frequent in elderly, respectively, 12.1% versus 1.6% (p = .005), and 44.8% versus 29.9% (p = .048). Anticardiolipin antibody (aCL) IgM was more frequently found in old patients compared to younger patients (33.9% vs 18.1%, p = .02), contrary to lupus anticoagulant (LAC) (52.8% vs 66.9%, p = .02). Older patients were more often diagnosed with single positive APS (82.8% vs 59.8% p = .002). The thrombotic relapse free survival was lower in elderly APS patients (p = .044) compared to younger APS. Elderly APS patients had more recurrent arterial and venous thrombosis (p = .03) and had poorer overall survival (p = .004) than elderly controls.

CONCLUSION

In this study, APS was different in patients aged more than 65 years, with a male predominance and more myocardial infarctions and LLDVT at diagnosis. Single antiphopholipid positivity and aCL IgM were more frequent in older patients. Older patient with APS had more thrombotic recurrence during follow-up. Compared to elderly controls, elderly APS patients had more thrombosis recurrences and poorer survival.

Implementation of the new EUR IVD regulation and relation with ISO15189 accreditation: Guidance is urgently required for haemostasis testing

On May 26th 2017 the European Parliament and the Council of The European Union adopted the new regulation on in vitro diagnostic medical devices (IVDR)-Regulation EU 2017/746-planned to be applied from May 26th 2022 in substitution to the previous IVD directives (IVDD 98/79 EC). After several health and legal causes due to medical device malfunctions, the European Union (EU) extensively reviewed the previous regulatory, which had remained unchanged since 1998. Aim of the work is to analyse the effects of the new IVDR on the field of haemostasis and thrombosis testing with particular attention to specific clinical conditions. Clinical laboratories will mainly deal with three different situations: (1) Diagnostic test performed with IVDR products used according with clinical indication certified by manufacturers. (2) Diagnostic test performed with certified IVDR products without clinical validation. (3) Diagnostic test performed with reagents classified as Research Use Only (RUO). At present, only few clinical laboratories through different European countries have been prepared to the new IVDR, while many laboratories are not yet aware about crucial aspects of the new process that deeply involves laboratory medicine. In conclusion, each laboratory should be aware of the IVDR certification of the reagents/instruments used in its laboratory. There are several urgent needs regarding IVDR certification: studies about the clinical performance of haemostasis tests, guidelines for LDTs (definition and documentation), internal and external quality controls for the tests recommended/suggested in the guidance/guidelines and finally implementation and/or update of clinical and laboratory guidelines.

Lupus anticoagulant associates with thrombosis in patients with COVID-19 admitted to intensive care units: A retrospective cohort study

Background

Thrombosis is a frequent and severe complication in patients with coronavirus disease 2019 (COVID‐19) admitted to the intensive care unit (ICU). Lupus anticoagulant (LA) is a strong acquired risk factor for thrombosis in various diseases and is frequently observed in patients with COVID‐19. Whether LA is associated with thrombosis in patients with severe COVID‐19 is currently unclear.

Objective

To investigate if LA is associated with thrombosis in critically ill patients with COVID‐19.

Patients/Methods

The presence of LA and other antiphospholipid antibodies was assessed in patients with COVID‐19 admitted to the ICU. LA was determined with dilute Russell's viper venom time (dRVVT) and LA‐sensitive activated partial thromboplastin time (aPTT) reagents.

Results

Of 169 patients with COVID‐19, 116 (69%) tested positive for at least one antiphospholipid antibody upon admission to the ICU. Forty (24%) patients tested positive for LA; of whom 29 (17%) tested positive with a dRVVT, 19 (11%) tested positive with an LA‐sensitive aPTT, and 8 (5%) tested positive on both tests. Fifty‐eight (34%) patients developed thrombosis after ICU admission. The odds ratio (OR) for thrombosis in patients with LA based on a dRVVT was 2.5 (95% confidence interval [CI], 1.1–5.7), which increased to 4.5 (95% CI, 1.4–14.3) in patients at or below the median age in this study (64 years). LA positivity based on a dRVVT or LA‐sensitive aPTT was only associated with thrombosis in patients aged less than 65 years (OR, 3.8; 95% CI, 1.3–11.4) and disappeared after adjustment for C‐reactive protein.

Conclusion

Lupus anticoagulant on admission is strongly associated with thrombosis in critically ill patients with COVID‐19, especially in patients aged less than 65 years.