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OBJECTIVE: To develop new antiphospholipid syndrome (APS) classification criteria with high specificity for use in observational studies and trials, jointly supported by the American College of Rheumatology (ACR) and EULAR. METHODS: This international multidisciplinary initiative included four phases: (1) Phase I, criteria generation by surveys and literature review; (2) Phase II, criteria reduction by modified Delphi and nominal group technique exercises; (3) Phase III, criteria definition, further reduction with the guidance of real-world patient scenarios, and weighting via consensus-based multicriteria decision analysis, and threshold identification; and (4) Phase IV, validation using independent adjudicators' consensus as the gold standard. RESULTS: The 2023 ACR/EULAR APS classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL-associated clinical criterion, followed by additive weighted criteria (score range 1-7 points each) clustered into six clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and two laboratory domains (lupus anticoagulant functional coagulation assays, and solid-phase enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti-ß2-glycoprotein I antibodies). Patients accumulating at least three points each from the clinical and laboratory domains are classified as having APS. In the validation cohort, the new APS criteria vs the 2006 revised Sapporo classification criteria had a specificity of 99% vs 86%, and a sensitivity of 84% vs 99%. CONCLUSION: These new ACR/EULAR APS classification criteria were developed using rigorous methodology with multidisciplinary international input. Hierarchically clustered, weighted, and risk-stratified criteria reflect the current thinking about APS, providing high specificity and a strong foundation for future APS research.
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Síndrome Antifosfolipídica , Reumatologia , Feminino , Gravidez , Humanos , Síndrome Antifosfolipídica/diagnóstico , Autoanticorpos , Imunoglobulina G , Imunoglobulina MRESUMO
The diagnosis of antiphospholipid syndrome (APS) relies on the detection of circulating antiphospholipid antibodies (aPL). Currently, lupus anticoagulant (LA), anticardiolipin (aCL), and anti-ß2-glycoprotein I antibodies (aß2GPI) IgG or IgM are the laboratory criteria if persistently present over time. As aCL and aß2GPI are two out of the three laboratory criteria, the detection of aPL by solid phase assays is an essential step in the diagnosis of APS. Advancement has been made to resolve some of the methodological challenges of aCL and aß2GPI assays by providing guidelines how to measure aPL, as well as to gain a better understanding of their diagnostic role. However, solid phase assays for aCL and aß2GPI still show substantive inter-assay differences, resulting in disagreement concerning positive/negative results, but also differences in titer of antibodies. This hampers the semiquantitative classification into low-medium-high positivity. The non-criteria aPL, such as antibodies against the domain one of ß2GPI and anti-phosphatidylserine/prothrombin antibodies (aPS/PT) have roles in confirming the risk in APS, and can be useful, especially in patients with incomplete antibody profiles.
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Síndrome Antifosfolipídica , Inibidor de Coagulação do Lúpus , Anticorpos Anticardiolipina , Anticorpos Antifosfolipídeos , Síndrome Antifosfolipídica/diagnóstico , Humanos , Imunoglobulina G , Imunoglobulina M , Protrombina , beta 2-Glicoproteína IRESUMO
PURPOSE OF THE REVIEW: This review focuses on the laboratory tests necessary for the diagnosis of antiphospholipid syndrome (APS). For the interpretation of the results of the tests for antiphospholipid antibodies (aPL), understanding of all pitfalls and interferences is necessary. RECENT FINDINGS: Progress has been made on the standardization of aPL tests and current guidelines for detection of lupus anticoagulant (LAC), anticardiolipin antibodies (aCL), and antibeta2-glycoprotein I antibodies (aß2GPI) are useful tools. LAC measurement remains a complex procedure with many pitfalls and interference by anticoagulant therapy. Solid phase assays for aCL and aß2GPI still show inter-assay differences. Measuring LAC, aCL, and aß2GPI allows making antibody profiles that help in identifying patients at risk. Other aPL, such as antibodies against domain I of beta2-glycoprotein I (aDI) and antiphosphatidylserine-prothrombin (aPS/PT) antibodies, may be useful in risk stratification of APS patients, but are not included in the current diagnostic criteria as no added value in the diagnosis of APS has been illustrated so far. The laboratory diagnosis of APS remains challenging. LAC, aCL, aß2GPI IgG, and IgM should be performed to increase diagnostic efficacy, with an integrated interpretation of all results and an interpretative comment. A close interaction between clinical pathologists and clinicians is mandatory.
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Anticorpos Antifosfolipídeos/análise , Síndrome Antifosfolipídica , Anticorpos Anticardiolipina , Síndrome Antifosfolipídica/diagnóstico , Técnicas de Laboratório Clínico , Humanos , beta 2-Glicoproteína I/imunologiaRESUMO
BACKGROUND: Transfusion of cryopreserved platelets (cryoplatelets) is not common but may replace standard liquid-preserved platelets (PLTs) in specific circumstances. To better understand cryoplatelet function, frozen concentrates from different manufacturing sites were compared. STUDY DESIGN AND METHODS: Cryoplatelets from Denver, Colorado (DEN); Sydney, Australia (SYD); and Ghent, Belgium (GHE) were compared (n = 6). A paired noncryopreserved control was included in Ghent. Microfluidic-flow chambers were used to study PLT adhesion and fibrin deposition in reconstituted blood. Receptor expression was measured by flow cytometry. Coagulation in static conditions was evaluated by rotational thromboelastometry (ROTEM). RESULTS: Regardless of the manufacturing site, adhesion of cryoplatelets under shear flow (1000/sec) was significantly (p < 0.05) reduced compared to control. Expression of GPIbα was decreased in a subpopulation of cryoplatelets comprising 45% ± 11% (DEN), 63% ± 9% (GHE), and 94% ± 6% (SYD). That subpopulation displayed increased annexin V binding and decreased integrin activation. PLT adhesion, agglutination, and aggregation were moreover decreased in proportion to that subpopulation. Fibrin deposition under shear flow was normal but initiated faster (546 ± 163 sec GHE) than control PLTs (631 ± 120 sec, p < 0.01), only in the absence of tissue factor. In static conditions, clotting time was faster, but clot firmness decreased compared to control. Coagulation was not different between manufacturing sites. CONCLUSION: Cryopreservation results in a subset of PLTs with enhanced GPIbα shedding, increased phosphatidylserine expression, reduced integrin response, and reduced adhesion to collagen in microfluidic models of hemostasis. The proportion of this phenotype is different between manufacturing sites. The clinical effects, if any, will need to be verified.
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Plaquetas/fisiologia , Criopreservação/métodos , Preservação de Sangue/métodos , Western Blotting , Humanos , Agregação Plaquetária/fisiologia , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , TromboelastografiaRESUMO
BACKGROUND: Lupus anticoagulant (LAC) detection represents diagnostic challenges among which the multitude of available reagents and interference by anticoagulant treatment. One of the two advised tests is the dilute Russell's viper venom time (dRVVT). However, it is currently not clear whether all dRVVT reagents may be considered equivalent. The objective of the study was to evaluate the diagnostic performance of two dRVVT reagents, with special attention to the influence of anticoagulant therapy. METHODS: STA®-Staclot® dRVV Screen/Confirm (Stago, Asnières-sur-Seine, France) and dRVT-LS/dRVTL-LR (Haematex, Hornsby, Australia) were evaluated on 443 patient samples [358 consecutive patients with LAC request including six antiphospholipid syndrome (APS) patients, 18 non-consecutively selected APS patients and 37 vitamin K antagonists (VKA)-treated and 30 direct oral anticoagulants (DOAC)-treated non-APS patients]. Additionally, pooled normal plasma (PNP) was spiked with factor deficient plasma (n=33) and DOAC calibrators (n=21) to evaluate sensitivity for factor deficiencies and false-positivity rates, respectively. RESULTS: A higher number of samples were defined as LAC positive by Stago vs. Haematex [11.5% (41/358) vs. 3.63% (13/358)]. Most discordances were in the VKA and DOAC group. Haematex was less prone to VKA-related factor deficiencies, explaining the absence of false-positive LAC results in VKA-treated non-APS patients compared to 10.8% with Stago. We observed no false-positive LAC ratios with Haematex in DOAC-spiked PNP and a lower number in DOAC-treated non-APS patients. However, increased specificity seemed to be at cost of a reduced sensitivity as Haematex showed less positive APS patient samples (45.8% vs. 87.5%). CONCLUSIONS: dRVVT reagents differ in LAC sensitivity and for VKA and DOAC interference.
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Indicadores e Reagentes/química , Inibidor de Coagulação do Lúpus/sangue , Tempo de Protrombina , Testes de Coagulação Sanguínea , HumanosRESUMO
BACKGROUND: Lupus anticoagulant (LAC) testing includes a screening, mixing and confirmation step. Although recently published guidelines on LAC testing are a useful step towards standardization, a lack of consensus remains whether to express mixing tests in clotting time (CT) or index of circulating anticoagulant (ICA). The influence of anticoagulant therapy, e.g. vitamin K antagonists (VKA) or direct oral anticoagulants (DOAC) on both methods of interpretation remains to be investigated. The objective of this study was to contribute to a simplification and standardization of the LAC three-step interpretation on the level of the mixing test. METHODS: Samples from 148 consecutive patients with LAC request and prolonged screening step, and 77 samples from patients non-suspicious for LAC treated with VKA (n=37) or DOAC (n=30) were retrospectively evaluated. An activated partial thromboplastin time (aPTT) and dilute Russell's viper venom time (dRVVT) were used for routine LAC testing. The supplemental anticoagulant samples were tested with dRVVT only. We focused on the interpretation differences for mixing tests expressed as CT or ICA and compared the final LAC conclusion within each distinct group of concordant and discordant mixing test results. RESULTS: Mixing test interpretation by CT resulted in 10 (dRVVT) and 16 (aPTT) more LAC positive patients compared to interpretation with ICA. Isolated prolonged dRVVT screen mix ICA results were exclusively observed in samples from VKA-treated patients without suspicion for LAC. CONCLUSIONS: We recommend using CT in respect to the 99th percentile cut-off for interpretation of mixing steps in order to reach the highest sensitivity and specificity in LAC detection.
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Anticoagulantes/farmacologia , Inibidor de Coagulação do Lúpus/metabolismo , Anticoagulantes/administração & dosagem , Testes de Coagulação Sanguínea , Humanos , Inibidor de Coagulação do Lúpus/sangue , Tempo de Tromboplastina Parcial , Tempo de Protrombina , Estudos Retrospectivos , Vitamina K/antagonistas & inibidoresRESUMO
Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombotic manifestations and/or obstetric complications in patients with persistently positive antiphospholipid antibodies (aPL). aPL are a heterogeneous group of autoantibodies, but only lupus anticoagulant, anticardiolipin (aCL), and antibeta2-glycoprotein I antibodies (aß2GPI) IgG or IgM are included as laboratory classification criteria. Seronegative APS patients are usually defined as patients with the clinical symptoms of APS but who test negative for aPL. The negativity to classic aPL criteria does not exclude the presence of other aPL. Several noncriteria aPL have been identified. Some noncriteria aPL are well studied, such as IgA aCL and aß2GPI, the antiphosphatidylserine-prothrombin (aPS/PT) antibodies, and the antibodies against the domain I of beta2-glycoprotein I (aDI), both latter groups receiving more attention for their role in thrombotic events and pregnancy complications. Other noncriteria aPL that have been studied are antibodies against annexin V, prothrombin, phosphatidylethanolamine, phosphatidic acid, phosphatidylserine, phosphatidylinositol, vimentin-cardiolipin complex, anti-protein S/protein C. Measurement of some of these noncriteria aPL (aPS/PT, aDI) is useful in the laboratory work-out of APS in specific situations. We have to differentiate between patients who are positive for noncriteria aPL only, and patients who have both criteria and noncriteria aPL to enable us to study their role in the diagnosis or risk stratification of APS. The research on noncriteria aPL is continually developing as the clinical relevance of these antibodies is not yet fully clarified.
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Anticorpos Antifosfolipídeos , Síndrome Antifosfolipídica , Humanos , Síndrome Antifosfolipídica/imunologia , Síndrome Antifosfolipídica/diagnóstico , Síndrome Antifosfolipídica/sangue , Anticorpos Antifosfolipídeos/sangue , Anticorpos Antifosfolipídeos/imunologia , Feminino , Gravidez , Trombose/etiologia , Trombose/imunologia , Trombose/sangue , Trombose/diagnóstico , beta 2-Glicoproteína I/imunologia , Autoanticorpos/sangue , Autoanticorpos/imunologiaRESUMO
BACKGROUND: Improving harmonization of the clinical interpretation of anticardiolipin (aCL) and anti-ß2-glycoprotein I (aß2GPI) 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/aß2GPI results. OBJECTIVES: To determine moderate and high thresholds for aCL and aß2GPI IgG/IgM measured with chemiluminescent immunoassay, enzyme-linked immunosorbent assay, fluorescence enzyme immunoassay, and multiplex flow immunoassay. METHODS: aCL and aß2GPI 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 aß2GPI 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 aß2GPI IgG/IgM moderate and high thresholds were determined for 4 analytical platforms. Thresholds improve harmonized interpretation of aCL/aß2GPI levels across platforms. The proposed thresholds should be verified in an independent case-control study to check interlaboratory transferability.
Assuntos
Anticorpos Anticardiolipina , Síndrome Antifosfolipídica , Imunoglobulina G , Inibidor de Coagulação do Lúpus , beta 2-Glicoproteína I , Síndrome Antifosfolipídica/diagnóstico , Síndrome Antifosfolipídica/sangue , Síndrome Antifosfolipídica/imunologia , Humanos , Anticorpos Anticardiolipina/sangue , beta 2-Glicoproteína I/imunologia , Inibidor de Coagulação do Lúpus/sangue , Estudos de Casos e Controles , Imunoglobulina G/sangue , Feminino , Masculino , Anticorpos Antifosfolipídeos/sangue , Funções Verossimilhança , Imunoglobulina M/sangue , Valor Preditivo dos Testes , Ensaio de Imunoadsorção Enzimática/normas , Ensaio de Imunoadsorção Enzimática/métodos , Pessoa de Meia-Idade , Adulto , Reprodutibilidade dos Testes , Biomarcadores/sangue , Medições LuminescentesRESUMO
ABSTRACT: Thrombosis is an important manifestation of the antiphospholipid syndrome (APS). The thrombin generation (TG) test is a global hemostasis assay, and increased TG is associated with thrombosis. APS is currently diagnosed based on clinical and laboratory criteria, the latter defined as anti-cardiolipin, anti-ß2-glycoprotein I antibodies, or lupus anticoagulant (LA). APS testing is often performed after a thrombotic episode and subsequent administration of anticoagulation, which might hamper the interpretation of clotting assays used for LA testing. We set out to develop an artificial neural network (NN) that can diagnose APS in patients who underwent vitamin K antagonist (VKA) treatment, based on TG test results. Five NNs were trained to diagnose APS in 48 VKA-treated patients with APS and 64 VKA-treated controls, using TG and thrombin dynamics parameters as inputs. The 2 best-performing NNs were selected (accuracy, 96%; sensitivity, 96%-98%; and specificity, 95%-97%) and further validated in an independent cohort of VKA-anticoagulated patients with APS (n = 33) and controls (n = 62). Independent clinical validation favored 1 of the 2 selected NNs, with a sensitivity of 88% and a specificity of 94% for the diagnosis of APS. In conclusion, the combined use of TG and NN methodology allowed for us to develop an NN that diagnoses APS with an accuracy of 92% in individuals with VKA anticoagulation (n = 95). After further clinical validation, the NN could serve as a screening and diagnostic tool for patients with thrombosis, especially because there is no need to interrupt anticoagulant therapy.
Assuntos
Síndrome Antifosfolipídica , Trombose , Humanos , Síndrome Antifosfolipídica/diagnóstico , Síndrome Antifosfolipídica/tratamento farmacológico , Trombina/farmacologia , Anticoagulantes/efeitos adversos , Coagulação Sanguínea , Inibidor de Coagulação do Lúpus , Trombose/diagnóstico , Trombose/tratamento farmacológico , Trombose/etiologiaRESUMO
BACKGROUND: Cardiac catheterizations in horses are mainly performed in the right heart, as access to the left heart traditionally requires an arterial approach. Transseptal puncture (TSP) has been adapted for horses but data on follow-up and closure of the iatrogenic atrial septal defect (iASD) are lacking. HYPOTHESIS/OBJECTIVES: To perform TSP and assess postoperative complications and iASD closure over a minimum of 4 weeks. ANIMALS: Eleven healthy adult horses. METHODS: Transseptal puncture was performed under general anesthesia. Serum cardiac troponin I concentrations were measured before and after puncture. Weekly, iASD closure was monitored using transthoracic and intracardiac echocardiography. Relationship between activated clotting time and anti-factor Xa activity during postoperative enoxaparin treatment was assessed in vitro and in vivo. RESULTS: Transseptal puncture was successfully achieved in all horses within a median duration of 22 (range, 10-104) minutes. Balloon dilatation of the puncture site for sheath advancement was needed in 4 horses. Atrial arrhythmias occurred in 9/11 horses, including atrial premature depolarizations (N = 1), atrial tachycardia (N = 5), and fibrillation (N = 3). Serum cardiac troponin I concentrations increased after TSP, but remained under the reference value in 10/11 horses. Median time to iASD closure was 14 (1-35) days. Activated clotting time correlated with anti-factor Xa activity in vitro but not in vivo. CONCLUSIONS AND CLINICAL IMPORTANCE: Transseptal puncture was successfully performed in all horses. The technique was safe and spontaneous iASD closure occurred in all horses. Clinical application of TSP will allow characterization and treatment of left-sided arrhythmias in horses.
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BACKGROUND: The 2023 ACR/EULAR Antiphospholipid Syndrome (APS) Classification Criteria development, aiming to identify patients with high likelihood of APS for research, employed a four-phase methodology. Phase I and II resulted in 27 proposed candidate criteria, organized into laboratory and clinical domains. Here, we summarize the last stage of Phase III efforts employing a consensus-based multi-criteria decision analysis (MCDA) to weigh candidate criteria and identify an APS classification threshold score. METHODS: We evaluated 192 unique, international real-world cases referred for "suspected APS" with a wide range of APS manifestations. Using proposed candidate criteria, subcommittee members rank-ordered 20 representative cases from highly unlikely to highly likely APS. During an in-person meeting, the subcommittee refined definitions and participated in an MCDA exercise to identify relative weights of candidate criteria. Using consensus decisions and pairwise criteria comparisons, 1000Minds™ software assigned criteria weights, and we rank ordered 192 cases by their additive scores. A consensus-based threshold score for APS classification was set. RESULTS: Pre-meeting evaluation of 20 representative cases demonstrated variability in APS assessment. MCDA resolved 81 pairwise decisions; relative weights identified domain item hierarchy. After assessing 192 cases by weights and additive scores, the Steering Committee reached consensus that APS classification should require separate clinical and laboratory scores, rather than a single aggregate score, to ensure high specificity. CONCLUSION: Using MCDA, candidate criteria preliminary weights were determined. Unlike other disease classification systems using a single aggregate threshold score, separate clinical and laboratory domain thresholds were incorporated into the new APS classification criteria.
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BACKGROUND: Accelerated vascular calcification and increased risk of calciphylaxis can be a reason to restrict the use of vitamin K antagonists in dialysis patients. We describe the use of fondaparinux, a prototype indirect factor Xa inhibitor, as an alternative anticoagulant to coumarin derivatives in dialysis patients. METHODS: In this case series, we included six chronic haemodialysis patients treated with vitamin K antagonists. Low-molecular-weight heparin given as anticoagulant during dialysis was replaced by fondaparinux. Anti-Xa activity was regularly measured pre- and postdialysis to adapt the dose of fondaparinux. Adequate continuous anticoagulation and circuit patency were registered by evaluating clotting in the bubble trap and dialyser membrane at the end of dialysis. RESULTS: Anticoagulation with fondaparinux at a starting dose of 2.5 mg resulted in an effective anticoagulation in the majority of dialysis sessions. Although median predialysis anti-Xa levels were significantly lower [0.36 IU/mL (0.30-0.42 IU/mL) (P < 0.0001)] than postdialysis levels [0.75 IU/mL (0.65-0.80 IU/mL)], predialysis anti-Xa levels were sufficient to limit the risk of thromboembolism. After an initial period of gradually increasing anti-Xa levels due to accumulation of fondaparinux, stable levels were achieved. Haemodialysis without clotting problems was possible in 96% of the sessions (clotting score ≤1), whereas two episodes (2/459 dialysis sessions) of major clotting were observed, defined as clotting of the extracorporeal circuit necessitating premature termination of the procedure. CONCLUSIONS: We demonstrated that fondaparinux is a valuable anticoagulant for patients dialysed with low-flux membranes in need of continuous anticoagulation.
Assuntos
Anticoagulantes/uso terapêutico , Fibrilação Atrial/tratamento farmacológico , Coagulação Sanguínea/efeitos dos fármacos , Hemorragia/tratamento farmacológico , Polissacarídeos/uso terapêutico , Diálise Renal , Vitamina K/antagonistas & inibidores , Idoso , Idoso de 80 Anos ou mais , Fibrilação Atrial/etiologia , Contraindicações , Feminino , Fibrinolíticos/farmacologia , Fondaparinux , Hemorragia/induzido quimicamente , Humanos , Masculino , VarfarinaRESUMO
Since the discovery that antiphospholipid antibodies (aPL) bind to a cofactor at the phospholipid membrane, the proteins beta-2-glycoprotein I (ß2GPI) and prothrombin seemed to be the antigens of importance in the antiphospholipid syndrome (APS). Anti-ß2GPI antibodies (aß2GPI) were soon included in the classification criteria, while anti-prothrombin antibodies (aPT) are still regarded as "non-criteria" aPL. Evidence is accumulating that antibodies against prothrombin are clinically relevant and closely associated with APS and the presence of lupus anticoagulant (LA). Among the non-criteria aPL, anti-phosphatidylserine/prothrombin antibodies (aPS/PT) are one of the most frequently studied aPL. More and more studies illustrate the evidence of the pathogenic capacity of these antibodies. aPS/PT IgG and IgM are associated with arterial and venous thrombosis, show an overlap with LA presence, and are frequently present in triple-positive patients, regarded as patients at highest risk for APS-related clinical symptoms. Moreover, the association of aPS/PT with thrombosis increases with higher titers, confirming that presence of aPS/PT consolidates the risk. So far, the added value of aPS/PT on top of the criteria aPL to diagnose APS is not clear with opposing findings in literature. Described in this chapter is the procedure for detecting these antibodies with a commercial ELISA, which can be used to determine the presence of IgG and IgM aPS/PT in human samples. Additionally, general guidelines that will facilitate optimal performance of the aPS/PT assay will be provided.
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Síndrome Antifosfolipídica , Protrombina , Humanos , Fosfatidilserinas , Anticorpos Antifosfolipídeos , Síndrome Antifosfolipídica/diagnóstico , Inibidor de Coagulação do Lúpus , Imunoglobulina G , Imunoglobulina MRESUMO
Anti-ß2GPI antibodies (aß2GPI) are one of the laboratory criteria for antiphospholipid syndrome (APS), along with lupus anticoagulant (LA) and anticardiolipin antibodies (aCL). A subset of the aß2GPI are the antibodies directed toward the domain I of the ß2GPI (aDI). The aDI are regarded as non-criteria aPL and are among the most studied non-criteria aPL. Antibodies directed against a specific epitope in the domain I (G40-R43) of ß2GPI were shown to be strongly correlated with thrombotic and obstetric events in APS. Many studies illustrated the pathogenic capacity of these antibodies, although with various results, depending on the assay used. The first studies were performed with an in-house ELISA with high specificity for aDI toward the G40-R43 epitope. More recently, a commercial chemiluminescence immunoassay for aDI IgG became obtainable for diagnostic laboratories. Although the added value of aDI on top of the criteria aPL is not clear, with opposing findings in literature, the assay might help in the diagnosis of APS, identifying the patients at risk since aDI are frequently present with high titers in triple-positive patients (positive for LA, aß2GPI, and aCL). aDI can be used as a confirmatory test and is useful for proving the specificity of the aß2GPI antibodies. In this chapter, the procedure for detecting these antibodies is outlined, using an automated chemiluminescence assay which can be used to determine the presence of IgG aDI in human samples. General guidelines that will facilitate optimal performance of the aDI assay are also provided.
Assuntos
Anticorpos Antifosfolipídeos , Síndrome Antifosfolipídica , Feminino , Gravidez , Humanos , beta 2-Glicoproteína I , Síndrome Antifosfolipídica/diagnóstico , Inibidor de Coagulação do Lúpus , Anticorpos Anticardiolipina , Epitopos , Imunoglobulina GRESUMO
Background: The antiphospholipid syndrome (APS) is classified by the presence of antiphospholipid antibodies (aPL) and thrombotic and/or adverse obstetric outcomes. The diagnosis and risk assessment of APS is challenging. This systematic review investigated if the thrombin generation (TG) assay could be helpful for APS diagnosis and risk assessment. Methods: A systemic review was performed by searching two databases (MEDLINE and Embase) until March 31, 2022, using a search strategy with two concepts: APS and TG, and related keywords. Two reviewers independently screened the articles based on predefined inclusion and exclusion criteria. Data extraction and quality assessment with the Newcastle-Ottawa Scale (NOS) were performed independently. Synthesis Without Meta-analysis guidelines were followed for data synthesis reporting. Results: Fourteen studies with 677 APS and 1,349 control subjects were included with variable quality according to the NOS. Twelve studies measured TG via the calibrated automated thrombogram (CAT) method using a fluorogenic substrate, whereas two used a chromogenic substrate-based TG assay. One study compared the CAT assay to the fully-automated ST Genesia® (Stago, France). Two studies initiated TG using platelet-rich plasma, whereas the rest of the studies used platelet-poor plasma. Resistance to activated protein C (aPC) was examined in ten studies. They reported a significant increase in aPC-resistance in APS patients compared to healthy controls, aPL-carriers, and thrombotic controls. Based on two studies, the prevalence of aPC-resistance was higher in APS patients compared to healthy controls and thrombotic controls with odds ratios of 5.9 and 6.8-12.8, respectively (p < 0.05). In contrast, no significant difference in aPC-resistance was found between APS patients and autoimmune disease controls. Furthermore, 7/14 studies reported TG-parameters including peak height, endogenous thrombin potential, lag time, and time to peak, but these outcomes were highly variable between studies. Furthermore, TG methodology between studies differed greatly, impacting the comparability of the studies. Conclusion: aPC-resistance measured with TG was increased in APS patients compared to healthy and thrombotic controls, but the diagnostic and prognostic value is unclear compared to current diagnostic strategies. Studies of other TG-parameters were heterogeneous and more research is needed to identify their potential added value in APS diagnosis. Systematic Review Registration: https://www.PROSPERO/, identifier: CRD42022308363.
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BACKGROUND: The optimal strategy for diagnosis and antithrombotic treatment of patients with antiphospholipid syndrome (APS)-associated acute ischemic stroke (AIS), transient ischemic attack (TIA), or other brain ischemic injury is poorly defined. OBJECTIVES: The survey goal was to capture variations in diagnosis and antithrombotic treatment of APS-associated ischemic stroke and related disorders to inform guidance and clinical trials to define optimal management. METHODS: Professional colleagues, including key opinion leaders, were invited to complete a REDCap survey questionnaire initiated by the International Society on Thrombosis and Haemostasis Scientific and Standardisation Committee Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies. The survey data were tallied using simple descriptive statistics. RESULTS: There was generally good agreement on several aspects, including which patients to test for antiphospholipid antibodies (aPL), use of a lifelong vitamin K antagonist for AIS or recurrent TIA, and formal cognitive assessment for suspected cognitive impairment. There was less agreement on other aspects, including aPL testing for brain ischemic injury other than AIS/TIA or if an alternative cause for AIS or TIA exists; choice of aPL tests, their timing, and age cutoff; the aPL phenotype to trigger antithrombotic treatment; management for patent foramen ovale; antithrombotic treatment for first TIA or white matter hyperintensities; head magnetic resonance imaging specifications; and low-molecular-weight heparin dosing/anti-Xa monitoring in pregnancy. The survey highlighted that approximately 25% practice at dedicated APS clinics and <50% have a multidisciplinary team structure for patients with APS. CONCLUSION: Much of the variation in practice reflects the lack of evidence-based recommendations. The survey results should inform the development of a more uniform multidisciplinary consensus approach to diagnosis and antithrombotic treatment.
Assuntos
Síndrome Antifosfolipídica , Ataque Isquêmico Transitório , AVC Isquêmico , Acidente Vascular Cerebral , Tromboembolia , Gravidez , Feminino , Humanos , Síndrome Antifosfolipídica/complicações , Síndrome Antifosfolipídica/diagnóstico , Síndrome Antifosfolipídica/tratamento farmacológico , Inibidor de Coagulação do Lúpus , Fibrinolíticos/uso terapêutico , Anticorpos Antifosfolipídeos , Inquéritos e Questionários , Isquemia , Encéfalo , Comunicação , Tromboembolia/complicações , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/etiologiaRESUMO
BACKGROUND: The added value of antiphosphatidylserine/prothrombin antibodies (aPS/PT) in the diagnostic workup of antiphospholipid syndrome (APS) is unclear. Currently, diagnosis of thrombotic APS (TAPS) and obstetric APS (OAPS) requires persistent presence of lupus anticoagulant (LAC), anticardiolipin (aCL) immunoglobulin (Ig) G/IgM, or anti-ß2-glycoprotein I (aß2GPI) IgG/IgM antibodies. OBJECTIVES: To evaluate the role of aPS/PT IgG and IgM in OAPS. METHODS: aPS/PT IgG/IgM, aCL IgG/IgM, aß2GPI IgG/IgM, and LAC were determined in 653 patients (OAPS, TAPS, and controls). In-house aPS/PT cut-off values were calculated, titers and prevalence were compared between OAPS, TAPS, and controls and type of pregnancy morbidity. Sensitivity, specificity, likelihood ratios, and odds ratios (OR) with 95% CI were calculated. RESULTS: In OAPS, aPS/PT IgG and IgM showed an OR of 4.32 (95% CI, 2.54-7.36) and 3.37 (95% CI, 1.93-5.89), respectively, but the association was not independent of LAC. Prevalence and titers of aPS/PT IgG and IgM were lower in OAPS than in patients with TAPS. aPS/PT were more prevalent and showed higher titers in patients with late pregnancy loss than in patients with early pregnancy loss with a positivity of 86.4% and 39.3%, respectively. Higher aPS/PT titers did not increase the likelihood of having OAPS. CONCLUSION: The added value of aPS/PT testing in the current diagnostic workup of OAPS seems limited compared with LAC, aCL, and aß2GPI. aPS/PT might be useful in specific subsets of patients with OAPS. However, future multicentric studies are needed to elucidate the risk of less frequent and most severe obstetrical manifestations.
Assuntos
Síndrome Antifosfolipídica , Feminino , Humanos , Gravidez , Anticorpos Anticardiolipina , Anticorpos Antifosfolipídeos , Síndrome Antifosfolipídica/diagnóstico , Imunoglobulina G , Imunoglobulina M , Inibidor de Coagulação do Lúpus , Fosfatidilserinas , ProtrombinaRESUMO
BACKGROUND: Light transmission aggregation (LTA) is used widely by the clinical and research communities. Although it is a gold standard, there is a lack of interlaboratory harmonization. OBJECTIVES: The primary objective was to assess whether sources of activators (mainly adenosine diphosphate [ADP], collagen, arachidonic acid, epinephrine, and thrombin receptor activating peptide6) and ristocetin contribute to poor LTA reproducibility. The secondary objective was to evaluate interindividual variability of results to appreciate the distribution of normal values and consequently better interpret pathologic results. METHODS: An international multicenter study involving 28 laboratories in which we compared LTA results obtained with center-specific activators and a comparator that we supplied. RESULTS: We report variability in the potency (P) of activators in comparison with the comparator. Thrombin receptor activating peptide 6 (P, 1.32-2.68), arachidonic acid (P, 0.87-1.43), and epinephrine (P, 0.97-1.34) showed the greatest variability. ADP (P, 1.04-1.20) and ristocetin (P, 0.98-1.07) were the most consistent. The data highlighted clear interindividual variability, notably for ADP and epinephrine. Four profiles of responses were observed with ADP from high-responders, intermediate-responders, and low-responders. A fifth profile corresponding to nonresponders (5% of the individuals) was observed with epinephrine. CONCLUSION: Based on these data, the establishment and adoption of simple standardization principles should mitigate variability due to activator sources. The observation of huge interindividual variability for certain concentrations of activators should lead to a cautious interpretation before reporting a result as abnormal. Confidence can be taken from the fact that difference between sources is not exacerbated in patients treated with antiplatelet agents.
Assuntos
Agregação Plaquetária , Ristocetina , Humanos , Ácido Araquidônico/farmacologia , Reprodutibilidade dos Testes , Difosfato de Adenosina/farmacologia , Testes de Função Plaquetária/métodos , Inibidores da Agregação Plaquetária/farmacologia , Epinefrina/farmacologia , Comunicação , PlaquetasRESUMO
This year's Congress of the International Society of Thrombosis and Haemostasis (ISTH) took place in person in Montréal, Canada, from June 24-28, 2023. The conference, held annually, highlighted cutting-edge advances in basic, translational, population and clinical sciences relevant to the Society. As for all ISTH congresses, we offered a special, congress-specific scientific theme; this year, the special theme was immunothrombosis. Certainly, over the last few years, COVID-19 infection and its related thrombotic and other complications have renewed interest in the concepts of thromboinflammation and immunothrombosis; namely, the relationship between inflammation, infection and clotting. Other main scientific themes of the Congress included Arterial Thromboembolism, Coagulation and Natural Anticoagulants, Diagnostics and Omics, Fibrinolysis and Proteolysis, Hemophilia and Rare Bleeding Disorders, Hemostatic System in Cancer, Inflammation and Immunity, Pediatrics, Platelet Disorders, von Willebrand Disease and Thrombotic Microangiopathies, Platelets and Megakaryocytes, Vascular Biology, Venous Thromboembolism and Women's Health. Among other sessions, the program included 28 State-of-the-Art (SOA) sessions with a total of 84 talks given by internationally recognized leaders in the field. SOA speakers were invited to prepare brief illustrated reviews of their talks that were peer reviewed and are included in this article. These illustrated capsules highlight the major scientific advances with potential to impact clinical practice. Readers are invited to take advantage of the excellent educational resource provided by these illustrated capsules. They are also encouraged to use the image in social media to draw attention to the high quality and impact of the science presented at the Congress.