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

Research paper thumbnail of Characteristics of Patients With Antiphospholipid Antibody Positivity in the APS ACTION International Clinical Database and Repository

Arthritis Care & Research, 2020

ObjectiveTo describe the baseline characteristics of patients with positivity for antiphospholipi... more ObjectiveTo describe the baseline characteristics of patients with positivity for antiphospholipid antibodies (aPLs) who were enrolled in an international registry, the Antiphospholipid Syndrome (APS) Alliance for Clinical Trials and International Networking (APS ACTION) clinical database and repository, overall and by clinical and laboratory subtypes.MethodsThe APS ACTION registry includes adults who persistently had positivity for aPLs. We evaluated baseline sociodemographic and aPL‐related (APS classification criteria and “non‐criteria”) characteristics of patients overall and in subgroups (aPL‐positive without APS, APS overall, thrombotic APS only, obstetric APS only, and both thrombotic APS/obstetric APS). We assessed baseline characteristics of patients tested for the presence of three aPLs (lupus anticoagulant [LAC] test, anticardiolipin antibody [aCL], and anti–β2‐glycoprotein I [anti‐β2GPI]) antibodies by aPL profiles (LAC only, single, double, and triple aPL positivity).Re...

Research paper thumbnail of Rivaroxaban limits complement activation compared with warfarin in antiphospholipid syndrome patients with venous thromboembolism

Journal of Thrombosis and Haemostasis, Nov 1, 2016

Background Complement activation may play a major role in the pathogenesis of thrombotic antiphos... more Background Complement activation may play a major role in the pathogenesis of thrombotic antiphospholipid syndrome (APS). Coagulation proteases such as factor Xa can activate complement proteins. Aims To establish whether rivaroxaban, a direct factor Xa inhibitor, limits complement activation compared to warfarin in APS patients with previous venous thromboembolism (VTE). Methods 111 APS patients with previous VTE, on warfarin target INR 2.5, had blood samples taken at baseline and at day 42 after randomisation in the RAPS (Rivaroxaban in Antiphospholipid Syndrome) trial. Fifty-six patients remained on warfarin and 55 switched to rivaroxaban. Fifty-five normal controls (NC) were also studied. Markers of complement activation (C3a, C5a, terminal complement complex (SC5b-9) and Bb fragment), were assessed. Results APS patients had significantly higher complement activation markers compared to NC at both time points irrespective of the anticoagulant. There were no differences between the two patient groups at baseline, or patients remaining on warfarin at day 42. In 55 patients randomised to rivaroxaban, C3a, C5a and SC5b-9 were significantly lower at day 42; median (ng/mL) [confidence interval] 64 [29-125] vs 83 [35-147], 9 [2-15] vs 12 [4-18] and 171 [56-4 245] vs 201 [66-350] respectively, but levels of Bb were unchanged. There were no correlations between rivaroxaban levels and complement activation markers. Conclusions APS patients with previous VTE on warfarin exhibit significantly increased complement activation, which is likely to occur via the classical pathway, and is decreased by rivaroxaban administration. Rivaroxaban may therefore potentially provide benefit additional to its anticoagulant effect in this patient group by limiting complement activation.

Research paper thumbnail of Comparison of Acquired Activated Protein C Resistance, Using the CAT and ST-Genesia® Analysers and Three Thrombin Generation Methods, in APS and SLE Patients

Journal of Clinical Medicine, Dec 23, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of High prevalence of activated protein C resistance associated with high avidity anti-protein C antibodies in various antiphospholipid syndrome clinical phenotypes

Background: Patritumab plus cetuximab with platinum as first-line therapy for patients with recur... more Background: Patritumab plus cetuximab with platinum as first-line therapy for patients with recurrent and/or metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) was evaluated for safety and to determine the recommended phase-II combination dose. Methods: Patients aged ≥18 years with confirmed R/M SCCHN received intravenous patritumab (18- mg/kg loading dose [LD]); 9-mg/kg maintenance dose [MD] every 3 weeks [q3w]) + cetuximab (400- mg/m2 LD; 250-mg/m2 MD weekly) + cisplatin (100 mg/m2 q3w) or carboplatin (area under the curve [AUC] of 5) for 6 cycles or until toxicity, disease progression, or withdrawal. Primary endpoints were dose-limiting toxicities (DLTs; grade ≥3 [21-day observation period]) and treatment-emergent adverse events (TEAEs). Pharmacokinetics, human antihuman antibodies (HAHA), tumor response, progression free survival (PFS), and overall survival (OS) were assessed. Results: Fifteen patients completed a median (range) of 8.7 (2.0-20.7) patritumab cycles. No DLTs were reported. Serious AEs were reported in 9 patients (patritumab-related n=4). TEAEs (N=15 patients) led to patritumab interruption in 7 patients. Patritumab-related dose reductions were reported in 1 patient. Patritumab (18 mg/kg) pharmacokinetics (N=15) showed mean (standard deviation) AUC0-21d of 2,619 (560) µg∙day/mL and maximum concentration of 499.9 (90.4) µg/mL. All patients were HAHA-negative at study end (single, transient low titer in 1 patient). Tumor response rate (complete plus partial response; N=15) was 47%. Median (95% confidence interval) PFS and OS (N=15) were 7.9 (3.7-9.7) and 13.5 (6.6- 17.5) months, respectively. Conclusion: Patritumab (18-mg/kg LD, 9-mg/kg MD) plus cetuximab/platinum was tolerable, active in SCCHN, and was selected as the phase II dose-regimen.

Research paper thumbnail of Prevalence of anti-protein C antibodies and acquired activated protein C resistance and in systemic lupus erythematosus

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

Rheumatology

Objectives Our primary objective was to quantify damage burden measured by Damage Index for Antip... more 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, hyperl...

Research paper thumbnail of Fluctuation of Anti–Domain 1 and Anti–β2‐Glycoprotein I Antibody Titers Over Time in Patients With Persistently Positive Antiphospholipid Antibodies

Arthritis & Rheumatology

ObjectiveThe present study was undertaken to longitudinally evaluate titers of antibodies against... more ObjectiveThe present study was undertaken to longitudinally evaluate titers of antibodies against β2‐glycoprotein I (anti‐β2GPI) and domain 1 (anti‐D1), to identify predictors of variations in anti‐β2GPI and anti‐D1 titers, and to clarify whether antibody titer fluctuations predict thrombosis in a large international cohort of patients who were persistently positive for antiphospholipid antibodies (aPL) in the APS ACTION Registry.MethodsPatients with available blood samples from at least 4 time points (at baseline [year 1] and at years 2–4 of follow‐up) were included. Detection of anti‐β2GPI and anti‐D1 IgG antibodies was performed using chemiluminescence (BIO‐FLASH; INOVA Diagnostics).ResultsAmong 230 patients in the study cohort, anti‐D1 and anti‐β2GPI titers decreased significantly over time (P < 0.0001 and P = 0.010, respectively). After adjustment for age, sex, and number of positive aPL tests, we found that the fluctuations in anti‐D1 and anti‐β2GPI titer levels were associ...

Research paper thumbnail of Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION) Clinical Database & Repository Analysis: The Comparison of Real World and Core Laboratory Lupus Anticoagulant Results

Presented at: 15th International Congress on Antiphospholipid Antibodies, North Cyprus. (2016), Sep 1, 2016

Research paper thumbnail of The influence of anti-tissue factor pathway inhibitor (TFPI) antibodies on thrombin generation (TG) in thrombotic patients with and without antiphospholipid syndrome

Research paper thumbnail of Prevalence of anti-protein C antibodies and acquired activated protein C resistance and in systemic lupus erythematosus

Research paper thumbnail of Rivaroxaban limits complement activation in patients with thrombotic antiphospholipid syndrome

Research paper thumbnail of Clinical and Laboratory Characteristics of Persistently Antiphospholipid Antibody Positive Patients: Retrospective Results from Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION) Clinical Database and Repository (""Registry"")

Research paper thumbnail of Comparison of Acquired Activated Protein C Resistance, Using the CAT and ST-Genesia® Analysers and Three Thrombin Generation Methods, in APS and SLE Patients

Journal of Clinical Medicine, 2021

Background: Acquired activated protein C resistance (APCr) has been identified in antiphospholipi... more Background: Acquired activated protein C resistance (APCr) has been identified in antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). Objective: To assess agreement between the ST-Genesia® and CAT analysers in identifying APCr prevalence in APS/SLE patients, using three thrombin generation (TG) methods. Methods: APCr was assessed with the ST-Genesia using STG-ThromboScreen and with the CAT using recombinant human activated protein C and Protac® in 105 APS, 53 SLE patients and 36 thrombotic controls. Agreement was expressed in % and by Cohen’s kappa coefficient. Results: APCr values were consistently lower with the ST-Genesia® compared to the CAT, using either method, in both APS and SLE patients. Agreement between the two analysers in identifying APS and SLE patients with APCr was poor (≤65.9%, ≤0.20) or fair (≤68.5%, ≥0.29), regardless of TG method, respectively; no agreement was observed in thrombotic controls. APCr with both the ST Genesia and the CAT using Pr...

Research paper thumbnail of A one-point increase in the Damage Index for Antiphospholipid Syndrome (DIAPS) predicts mortality in thrombotic antiphospholipid syndrome

Clinical and Experimental Rheumatology

Research paper thumbnail of COVID-19 and antiphospholipid antibodies: A position statement and management guidance from AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION)

Lupus, 2021

Coronavirus disease 2019 (COVID-19) is associated with a high rate of thrombosis. Prolonged activ... more Coronavirus disease 2019 (COVID-19) is associated with a high rate of thrombosis. Prolonged activated partial thromboplastin times (aPTT) and antiphospholipid antibodies (aPL) are reported in COVID-19 patients. The majority of publications have not reported whether patients develop clinically relevant persistent aPL, and the clinical significance of new aPL-positivity in COVID-19 is currently unknown. However, the reports of aPL-positivity in COVID-19 raised the question whether common mechanisms exist in the pathogenesis of COVID-19 and antiphospholipid syndrome (APS). In both conditions, thrombotic microangiopathy resulting in microvascular injury and thrombosis is hypothesized to occur through multiple pathways, including endothelial damage, complement activation, and release of neutrophil extracellular traps (NETosis). APS-ACTION, an international APS research network, created a COVID-19 working group that reviewed common mechanisms, positive aPL tests in COVID-19 patients, and ...

Research paper thumbnail of Editorial: Autoimmune and Inflammatory Rheumatic Diseases: Identifying Biomarkers of Response to Therapy With Biologics

Frontiers in Pharmacology, 2021

Research paper thumbnail of Co-existence of Antibodies to Tissue Factor Pathway Inhibitor and Protein C May Provide a Marker for a Severe Thrombotic Phenotype

Research paper thumbnail of Thrombin generation testing to monitor warfarin anticoagulation in thrombotic antiphospholipid syndrome patients

Research paper thumbnail of Antiphospholipid Antibody Profile Stability Over Time: Prospective Results From the APS ACTION Clinical Database and Repository

The Journal of Rheumatology, 2020

ObjectiveThe APS ACTION Registry studies long-term outcomes in persistently antiphospholipid anti... more ObjectiveThe APS ACTION Registry studies long-term outcomes in persistently antiphospholipid antibody (aPL)-positive patients. Our primary objective was to determine whether clinically meaningful aPL profiles at baseline remain stable over time. Our secondary objectives were to determine (1) whether baseline characteristics differ between patients with stable and unstable aPL profiles, and (2) predictors of unstable aPL profiles over time.MethodsA clinically meaningful aPL profile was defined as positive lupus anticoagulant (LAC) test and/or anticardiolipin (aCL)/anti-β2 glycoprotein-I (anti–β2-GPI) IgG/M ≥ 40 U. Stable aPL profile was defined as a clinically meaningful aPL profile in at least two-thirds of follow-up measurements. Generalized linear mixed models with logit link were used for primary objective analysis.ResultsOf 472 patients with clinically meaningful aPL profile at baseline (median follow-up 5.1 yrs), 366/472 (78%) patients had stable aPL profiles over time, 54 (11%...

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

Research paper thumbnail of Characteristics of Patients With Antiphospholipid Antibody Positivity in the APS ACTION International Clinical Database and Repository

Arthritis Care & Research, 2020

ObjectiveTo describe the baseline characteristics of patients with positivity for antiphospholipi... more ObjectiveTo describe the baseline characteristics of patients with positivity for antiphospholipid antibodies (aPLs) who were enrolled in an international registry, the Antiphospholipid Syndrome (APS) Alliance for Clinical Trials and International Networking (APS ACTION) clinical database and repository, overall and by clinical and laboratory subtypes.MethodsThe APS ACTION registry includes adults who persistently had positivity for aPLs. We evaluated baseline sociodemographic and aPL‐related (APS classification criteria and “non‐criteria”) characteristics of patients overall and in subgroups (aPL‐positive without APS, APS overall, thrombotic APS only, obstetric APS only, and both thrombotic APS/obstetric APS). We assessed baseline characteristics of patients tested for the presence of three aPLs (lupus anticoagulant [LAC] test, anticardiolipin antibody [aCL], and anti–β2‐glycoprotein I [anti‐β2GPI]) antibodies by aPL profiles (LAC only, single, double, and triple aPL positivity).Re...

Research paper thumbnail of Rivaroxaban limits complement activation compared with warfarin in antiphospholipid syndrome patients with venous thromboembolism

Journal of Thrombosis and Haemostasis, Nov 1, 2016

Background Complement activation may play a major role in the pathogenesis of thrombotic antiphos... more Background Complement activation may play a major role in the pathogenesis of thrombotic antiphospholipid syndrome (APS). Coagulation proteases such as factor Xa can activate complement proteins. Aims To establish whether rivaroxaban, a direct factor Xa inhibitor, limits complement activation compared to warfarin in APS patients with previous venous thromboembolism (VTE). Methods 111 APS patients with previous VTE, on warfarin target INR 2.5, had blood samples taken at baseline and at day 42 after randomisation in the RAPS (Rivaroxaban in Antiphospholipid Syndrome) trial. Fifty-six patients remained on warfarin and 55 switched to rivaroxaban. Fifty-five normal controls (NC) were also studied. Markers of complement activation (C3a, C5a, terminal complement complex (SC5b-9) and Bb fragment), were assessed. Results APS patients had significantly higher complement activation markers compared to NC at both time points irrespective of the anticoagulant. There were no differences between the two patient groups at baseline, or patients remaining on warfarin at day 42. In 55 patients randomised to rivaroxaban, C3a, C5a and SC5b-9 were significantly lower at day 42; median (ng/mL) [confidence interval] 64 [29-125] vs 83 [35-147], 9 [2-15] vs 12 [4-18] and 171 [56-4 245] vs 201 [66-350] respectively, but levels of Bb were unchanged. There were no correlations between rivaroxaban levels and complement activation markers. Conclusions APS patients with previous VTE on warfarin exhibit significantly increased complement activation, which is likely to occur via the classical pathway, and is decreased by rivaroxaban administration. Rivaroxaban may therefore potentially provide benefit additional to its anticoagulant effect in this patient group by limiting complement activation.

Research paper thumbnail of Comparison of Acquired Activated Protein C Resistance, Using the CAT and ST-Genesia® Analysers and Three Thrombin Generation Methods, in APS and SLE Patients

Journal of Clinical Medicine, Dec 23, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of High prevalence of activated protein C resistance associated with high avidity anti-protein C antibodies in various antiphospholipid syndrome clinical phenotypes

Background: Patritumab plus cetuximab with platinum as first-line therapy for patients with recur... more Background: Patritumab plus cetuximab with platinum as first-line therapy for patients with recurrent and/or metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) was evaluated for safety and to determine the recommended phase-II combination dose. Methods: Patients aged ≥18 years with confirmed R/M SCCHN received intravenous patritumab (18- mg/kg loading dose [LD]); 9-mg/kg maintenance dose [MD] every 3 weeks [q3w]) + cetuximab (400- mg/m2 LD; 250-mg/m2 MD weekly) + cisplatin (100 mg/m2 q3w) or carboplatin (area under the curve [AUC] of 5) for 6 cycles or until toxicity, disease progression, or withdrawal. Primary endpoints were dose-limiting toxicities (DLTs; grade ≥3 [21-day observation period]) and treatment-emergent adverse events (TEAEs). Pharmacokinetics, human antihuman antibodies (HAHA), tumor response, progression free survival (PFS), and overall survival (OS) were assessed. Results: Fifteen patients completed a median (range) of 8.7 (2.0-20.7) patritumab cycles. No DLTs were reported. Serious AEs were reported in 9 patients (patritumab-related n=4). TEAEs (N=15 patients) led to patritumab interruption in 7 patients. Patritumab-related dose reductions were reported in 1 patient. Patritumab (18 mg/kg) pharmacokinetics (N=15) showed mean (standard deviation) AUC0-21d of 2,619 (560) µg∙day/mL and maximum concentration of 499.9 (90.4) µg/mL. All patients were HAHA-negative at study end (single, transient low titer in 1 patient). Tumor response rate (complete plus partial response; N=15) was 47%. Median (95% confidence interval) PFS and OS (N=15) were 7.9 (3.7-9.7) and 13.5 (6.6- 17.5) months, respectively. Conclusion: Patritumab (18-mg/kg LD, 9-mg/kg MD) plus cetuximab/platinum was tolerable, active in SCCHN, and was selected as the phase II dose-regimen.

Research paper thumbnail of Prevalence of anti-protein C antibodies and acquired activated protein C resistance and in systemic lupus erythematosus

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

Rheumatology

Objectives Our primary objective was to quantify damage burden measured by Damage Index for Antip... more 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, hyperl...

Research paper thumbnail of Fluctuation of Anti–Domain 1 and Anti–β2‐Glycoprotein I Antibody Titers Over Time in Patients With Persistently Positive Antiphospholipid Antibodies

Arthritis & Rheumatology

ObjectiveThe present study was undertaken to longitudinally evaluate titers of antibodies against... more ObjectiveThe present study was undertaken to longitudinally evaluate titers of antibodies against β2‐glycoprotein I (anti‐β2GPI) and domain 1 (anti‐D1), to identify predictors of variations in anti‐β2GPI and anti‐D1 titers, and to clarify whether antibody titer fluctuations predict thrombosis in a large international cohort of patients who were persistently positive for antiphospholipid antibodies (aPL) in the APS ACTION Registry.MethodsPatients with available blood samples from at least 4 time points (at baseline [year 1] and at years 2–4 of follow‐up) were included. Detection of anti‐β2GPI and anti‐D1 IgG antibodies was performed using chemiluminescence (BIO‐FLASH; INOVA Diagnostics).ResultsAmong 230 patients in the study cohort, anti‐D1 and anti‐β2GPI titers decreased significantly over time (P < 0.0001 and P = 0.010, respectively). After adjustment for age, sex, and number of positive aPL tests, we found that the fluctuations in anti‐D1 and anti‐β2GPI titer levels were associ...

Research paper thumbnail of Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION) Clinical Database & Repository Analysis: The Comparison of Real World and Core Laboratory Lupus Anticoagulant Results

Presented at: 15th International Congress on Antiphospholipid Antibodies, North Cyprus. (2016), Sep 1, 2016

Research paper thumbnail of The influence of anti-tissue factor pathway inhibitor (TFPI) antibodies on thrombin generation (TG) in thrombotic patients with and without antiphospholipid syndrome

Research paper thumbnail of Prevalence of anti-protein C antibodies and acquired activated protein C resistance and in systemic lupus erythematosus

Research paper thumbnail of Rivaroxaban limits complement activation in patients with thrombotic antiphospholipid syndrome

Research paper thumbnail of Clinical and Laboratory Characteristics of Persistently Antiphospholipid Antibody Positive Patients: Retrospective Results from Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION) Clinical Database and Repository (""Registry"")

Research paper thumbnail of Comparison of Acquired Activated Protein C Resistance, Using the CAT and ST-Genesia® Analysers and Three Thrombin Generation Methods, in APS and SLE Patients

Journal of Clinical Medicine, 2021

Background: Acquired activated protein C resistance (APCr) has been identified in antiphospholipi... more Background: Acquired activated protein C resistance (APCr) has been identified in antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). Objective: To assess agreement between the ST-Genesia® and CAT analysers in identifying APCr prevalence in APS/SLE patients, using three thrombin generation (TG) methods. Methods: APCr was assessed with the ST-Genesia using STG-ThromboScreen and with the CAT using recombinant human activated protein C and Protac® in 105 APS, 53 SLE patients and 36 thrombotic controls. Agreement was expressed in % and by Cohen’s kappa coefficient. Results: APCr values were consistently lower with the ST-Genesia® compared to the CAT, using either method, in both APS and SLE patients. Agreement between the two analysers in identifying APS and SLE patients with APCr was poor (≤65.9%, ≤0.20) or fair (≤68.5%, ≥0.29), regardless of TG method, respectively; no agreement was observed in thrombotic controls. APCr with both the ST Genesia and the CAT using Pr...

Research paper thumbnail of A one-point increase in the Damage Index for Antiphospholipid Syndrome (DIAPS) predicts mortality in thrombotic antiphospholipid syndrome

Clinical and Experimental Rheumatology

Research paper thumbnail of COVID-19 and antiphospholipid antibodies: A position statement and management guidance from AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION)

Lupus, 2021

Coronavirus disease 2019 (COVID-19) is associated with a high rate of thrombosis. Prolonged activ... more Coronavirus disease 2019 (COVID-19) is associated with a high rate of thrombosis. Prolonged activated partial thromboplastin times (aPTT) and antiphospholipid antibodies (aPL) are reported in COVID-19 patients. The majority of publications have not reported whether patients develop clinically relevant persistent aPL, and the clinical significance of new aPL-positivity in COVID-19 is currently unknown. However, the reports of aPL-positivity in COVID-19 raised the question whether common mechanisms exist in the pathogenesis of COVID-19 and antiphospholipid syndrome (APS). In both conditions, thrombotic microangiopathy resulting in microvascular injury and thrombosis is hypothesized to occur through multiple pathways, including endothelial damage, complement activation, and release of neutrophil extracellular traps (NETosis). APS-ACTION, an international APS research network, created a COVID-19 working group that reviewed common mechanisms, positive aPL tests in COVID-19 patients, and ...

Research paper thumbnail of Editorial: Autoimmune and Inflammatory Rheumatic Diseases: Identifying Biomarkers of Response to Therapy With Biologics

Frontiers in Pharmacology, 2021

Research paper thumbnail of Co-existence of Antibodies to Tissue Factor Pathway Inhibitor and Protein C May Provide a Marker for a Severe Thrombotic Phenotype

Research paper thumbnail of Thrombin generation testing to monitor warfarin anticoagulation in thrombotic antiphospholipid syndrome patients

Research paper thumbnail of Antiphospholipid Antibody Profile Stability Over Time: Prospective Results From the APS ACTION Clinical Database and Repository

The Journal of Rheumatology, 2020

ObjectiveThe APS ACTION Registry studies long-term outcomes in persistently antiphospholipid anti... more ObjectiveThe APS ACTION Registry studies long-term outcomes in persistently antiphospholipid antibody (aPL)-positive patients. Our primary objective was to determine whether clinically meaningful aPL profiles at baseline remain stable over time. Our secondary objectives were to determine (1) whether baseline characteristics differ between patients with stable and unstable aPL profiles, and (2) predictors of unstable aPL profiles over time.MethodsA clinically meaningful aPL profile was defined as positive lupus anticoagulant (LAC) test and/or anticardiolipin (aCL)/anti-β2 glycoprotein-I (anti–β2-GPI) IgG/M ≥ 40 U. Stable aPL profile was defined as a clinically meaningful aPL profile in at least two-thirds of follow-up measurements. Generalized linear mixed models with logit link were used for primary objective analysis.ResultsOf 472 patients with clinically meaningful aPL profile at baseline (median follow-up 5.1 yrs), 366/472 (78%) patients had stable aPL profiles over time, 54 (11%...