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Objective : An international multidisciplinary initiative, jointly supported by the American College of Rheumatology and European Alliance of Associations for Rheumatology, is underway to develop new rigorous classification criteria to identify patients with high likelihood of antiphospholipid syndrome (APS) for research purposes. The present study was undertaken to apply an evidence- and consensus-based approach to identify candidate criteria and develop a hierarchical organization of criteria within domains. Methods : During phase I, the APS classification criteria steering committee used systematic literature reviews and surveys of international APS physician scientists to generate a comprehensive list of items related to APS. In phase II, we reviewed the literature, administered surveys, formed domain subcommittees, and used Delphi exercises and nominal group technique to reduce potential APS candidate criteria. Candidate criteria were hierarchically organized into clinical and laboratory domains. Results : Phase I generated 152 candidate criteria, expanded to 261 items with the addition of subgroups and candidate criteria with potential negative weights. Using iterative item reduction techniques in phase II, we initially reduced these items to 64 potential candidate criteria organized into 10 clinical and laboratory domains. Subsequent item reduction methods resulted in 27 candidate criteria, hierarchically organized into 6 additive domains (laboratory, macrovascular, microvascular, obstetric, cardiac, and hematologic) for APS classification. Conclusion : Using data- and consensus-driven methodology, we identified 27 APS candidate criteria in 6 clinical or laboratory domains. In the next phase, the proposed candidate criteria will be used for real-world case collection and further refined, organized, and weighted to determine an aggregate score and threshold for APS classification.

Management for patients with antiphospholipid syndrome (APS) and arterial thrombosis is controversial. There are no prospective data demonstrating the superiority of high- or moderate-intensity anticoagulation with vitamin K antagonists over antiplatelet agents. Using 2 antiphospholipid antibody databases (single center [New York Presbyterian Hospital] and multicenter [Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking]), we retrospectively collected demographic and clinical data of patients with APS and arterial thrombosis. The primary outcome was recurrent thrombosis rate after initial arterial thrombosis in patients with APS treated with antiplatelet and/or anticoagulant therapy. We identified 139 patients with a median follow-up time of 4.24 years after initial thrombosis. Thirty-seven patients (27.3%) received anticoagulants, 43 (30.9%) antiplatelets, and 58 (41.7%) combined therapy. Sixteen patients (37.2%) in the antiplatelet group, 9 (23.7%) in the anticoagulant group, and 4 (6.9%) in the combined therapy group experienced recurrent thrombosis. We estimate that 20% of patients will experience a recurrence by 3.4, 7.3, and 16.3 years, respectively, depending on assignment to antiplatelet, anticoagulant, or combined therapy. These results suggest that combined therapy decreases the rate of and increases the time to thrombosis recurrence in patients with APS presenting with arterial thrombosis.

Background: The APS ACTION International Clinical Database and Repository includes a secure web-based data capture system storing patient information including demographics, antiphospholipid antibodies (aPL)-related medical history, and aPL tests. Despite efforts at harmonization, inter-assay variability remains a problem in aPL testing. As a clinical repository open to researchers, ensuring comparability between assays and consistency in results between APS ACTION laboratories is essential to the validity of studies emerging from this network. Objective: To assess the level of agreement between an aPL-registry inclusion and core laboratory (core lab) anticardiolipin antibody (aCL) and anti-β 2 -glycoprotein-I antibody (aβ 2 GPI) ELISA testing results. Methods: Patients are recruited from 25 international centers based on positive aPL tests at inclusion. All samples are retested at the corresponding national APS ACTION core lab to confirm aPL positivity based on standard validated protocols. We analysed the categorical agreement, degree of linear association, and correlation between inclusion (local laboratory) and core lab aPL tests. Samples were included in this study only if results of aPL testing with ELISA at baseline were available. Results: 497 registry samples underwent confirmatory aPL tests. Categorical agreement between the inclusion and core lab values, as expressed by Cohen's kappa coefficients, ranged between 0.61 and 0.80 (as substantial agreement). The correlation between quantitative results in the aCL and aβ 2 GPI was better for IgM and IgA compared to IgG (Spearman rho 0.789 and 0.666 vs. 0.600 for aCL and rho 0.892 and 0.744 vs. 0.432 for aβ 2 GPI). Conclusions: The results of inclusion for aCL and aβ 2 GPI tests used for recruitment into the registry were in agreement to the results obtained by the APS ACTION core laboratories; aCL and aβ 2 GPI results showed very good categorical agreement. This agreement increased when considering high titer (>40 units) samples. APS ACTION is a reliable and useful research resource for APS. © 2019 Elsevier Ltd

AntiPhospholipid Syndrome Alliance For Clinical Trials and InternatiOnal Networking (APS ACTION) is the first-ever international research network that has been created specifically to design and conduct well-designed, large-scale, multi-center clinical trials in persistently antiphospholipid antibody (aPL)-positive patients. The founding principle of the APS ACTION is that it is an internationally collaborative effort, open to qualified investigators across the globe who are committed to furthering our understanding of APS and its management. Due to the hard work and collaborative spirit of APS ACTION members, in early 2012, APS ACTION launched two important collaborative international projects: 1) a randomized controlled trial of hydroxychloroquine in the primary thrombosis prevention of persistently aPL-positive but thrombosis-free patients without other systemic autoimmune diseases; and 2) a web-based registry of aPL-positive patients with or without systemic autoimmune diseases, which will also include annual blood collection for aPL-testing and future basic science studies. In the end, we hope to find better treatments for antiphospholipid syndrome, which is a leading cause of thrombosis, pregnancy morbidity and other life-altering consequences, and to heighten awareness about this life-threatening, autoimmune condition. Lupus (2012) 21, 695–698.

The antiphospholipid syndrome (APS) is defined by the presence of thrombosis and/or pregnancy morbidity in combination with the persistent presence of circulating antiphospholipid antibodies: lupus anticoagulant, anticardiolipin antibodies and/or anti-β2-glycoprotein I antibodies in medium to high titers. The management of thrombosis in patients with APS is a subject of controversy. This set of recommendations is the result of an effort to produce guidelines for therapy within a group of specialist physicians in Cardiology, Neurology, Hematology, Rheumatology and Internal Medicine, with a clinical and research focus on APS. © The Author(s), 2011.

The aim of the present study was to evaluate the urea resistance and binding characteristics of anti-β2-glycoprotein I (antiβ2GPI) antibodies using standard anticardiolipin (aCL) and anti-β2GPI enzyme immunosorbent assays (ELISAs). Sera from patients with antiphospholipid syndrome (APS) (n = 22) and non-APS (n = 24), positive in a standard aCL ELISA, were tested in an anti-β2GPI ELISA performed in polystyrene-irradiated ELISA plates. Urea resistance aCL and anti-β2GPI ELISAs were performed by measuring the ability of antibodies to recognize antigen in the presence of 2 M urea. The serum dilution after urea treatment (D) expressed as a percentage of the serum dilution without urea treatment (D(o)) corresponding to the same optical density was defined as residual activity (RA = 100 D/D(o)). The higher the RA, the higher the resistance of the antibodies to urea. APS compared to non- APS sera had higher aCL binding (absorbance values ranging between 0.180 and 1.400; median, 0.717 vs 0.120-1.273; median, 0.250, respectively; P < 0.004). Six APS patients' sera had low aCL levels but they expressed RA ≥30%. Anti- β2GPI antibodies were detected in 15 of 22 APS vs 3 of 24 non-APS patients (P < 0.03); RA ≥30% was detected in 15 of 22 APS vs 1 of 23 non-APS patients (P < 0.004). Using a CL affinity column, antibodies were purified from three APS anti-β2GPI negative and three non-APS anti-β2GPI-positive patients and tested in a aCL ELISA, using highly purified bovine serum albumin (BSA) as a blocking agent (modified ELISA); reactivity was not detected in two APS and one non-APS sera. On the contrary, the reactivity of the purified antibodies was high when β2GPI was incubated with CL in the ELISA plates; thus some anti-β2GPI negative sera from APS patients recognized the CL/β2GPI complex, rather than CL or β2GPI alone. In conclusion, anti-β2GPI antibodies are common in the APS patients, but a number of such patients recognize the CL/β2GPI complex and not CL or β2GPI. Antibodies to either β2GPI or the CL/β2GPI complex derived from APS sera present a high resistance to urea. Anti-β2GPI antibodies of low urea resistance exist in a minority of non-APS patients with autoimmune disease.

This review has focused on some recent developments which have begun to define the immunologic specificity of aPL antibodies. These studies have revealed that these immunoglobulins are more complex than has been realised to date and, more importantly, they offer new approaches to investigate how the prothrombotic diathesis associated with aPL antibodies might arise.

The ability of tumour necrosis factor-alpha (TNF-alpha) to directly stimulate phospholipid turnover from human neutrophils was studied. Stimulation with recombinant human (rH) TNF-alpha induced the release of significant amounts of radioactivity from [3H]arachidonic acid-labelled neutrophils. This stimulation was equipotent to that induced by the bacterial tripeptide formyl-methionyl-leucylphenylalanine (FMLP). The time of maximum stimulated release varied between donors, with the most common maximal stimulation being 45 min. Dose-response experiments indicated that 100-1000 U/ml rH TNF-alpha were required for the maximum stimulatory effect. High-performance liquid chromatography analysis of the supernatants revealed that the radioactivity was associated with arachidonic acid, but not with its metabolites, indicating that TNF-alpha stimulates the release of arachidonic acid from cellular phospholipids but does not stimulate its metabolism. A comparison of TNF-alpha with other cytokines indicated that stimulation of arachidonic acid release paralleled the 'priming' of neutrophils for enhanced superoxide production, raising the possibility that phospholipid turnover and priming of neutrophils are causally related.