title: Reduction of annexin A5 anticoagulant ratio identifies antiphospholipid antibody-positive patients with adverse clinical outcomes.
abstract: Essentials Annexin A5 resistance is a mechanism for antiphospholipid (aPL) syndrome. 750 patients with history of thrombosis, pregnancy complications and controls were tested. Reduced annexin A5 anticoagulant ratios (A5R) correlate with aPL antibody multipositivity. Reduced A5R may identify patients with a propensity for thrombosis or pregnancy complications. Click to hear an ISTH Academy presentation on antiphospholipid antibody syndrome by Drs de Laat and Bertolaccini SUMMARY: Background Annexin A5 (A5) is a potent anticoagulant protein that shields anionic phospholipids from coagulation reactions. Previous studies showed that antibodies from patients with antiphospholipid (aPL) syndrome (APS) interfere with annexin A5 crystallization and anticoagulant activity. Objective The purpose of this study was to investigate whether reduced values in the annexin A5 anticoagulant ratio (A5R) assay (i.e. 'annexin A5 resistance') are associated with adverse clinical events in aPL antibody-positive patients. Patients/Methods In an initial discovery phase, a group of 679 patient samples from a 'real-world' tertiary care hospital population were tested for A5R. This was followed by a validation-phase cohort of 71 asymptomatic patients with aPL antibodies and no prior history of an adverse clinical event whose baseline samples were tested for A5R then subsequently observed for up to 4 years. Results In the discovery-phase group, we found a reduction of A5R in aPL antibody-positive patients with thrombosis and/or pregnancy complications compared with aPL antibody-negative patients and controls. In addition, reduced A5R values in both the discovery-phase group and validation-phase cohort correlated with the extent of multi-positivity for standard APS tests, which has also been shown to be associated with a risk of adverse clinical outcomes. Conclusion Reduced A5R values were associated with a multi-positivity profile in aPL antibody-positive patients within both groups and with the development of adverse clinical events.
authors.affiliation: Department of Pathology, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Wolgast
authors.affiliation: Departments of Obstetrics and Gynecology, Population Health and Environmental Medicine, New York University School of Medicine, New York, NY, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Arslan
authors.affiliation: Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, USA.
authors.forename: X-X
authors.initials: XX
authors.lastname: Wu
authors.affiliation: Department of Pathology, Mt Sinai Hospital, New York, NY, USA.
authors.forename: J N
authors.initials: JN
authors.lastname: Beyda
authors.affiliation: Department of Cardiac Thoracic and Vascular Sciences, University Hospital Padova, Padua, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Pengo
authors.affiliation: Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Rand
mesh_terms: D000022:Abortion, Spontaneous; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017304:Annexin A5 / Q000737:chemistry* / Q000276:immunology; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D000925:Anticoagulants / Q000737:chemistry*; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000276:immunology; D001777:Blood Coagulation; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000737:chemistry; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000097:blood* / Q000276:immunology; D013927:Thrombosis / Q000097:blood* / Q000276:immunology; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D017304:Annexin A5; D017152:Antibodies, Antiphospholipid; D000925:Anticoagulants; D010743:Phospholipids
keywords: Annexin A5; antiphospholipid antibodies; antiphospholipid syndrome; pregnancy complications; thrombosis