title: Immunoglobulin G is the only anti-beta-2-glycoprotein I isotype that associates with unprovoked thrombotic events among hospital patients.
abstract: This study aimed to determine the strength of association between anti-beta-2-glycoprotein I (anti-β(2)GPI) isotypes and thrombotic events by phenotyping hospital patients tested for diagnostic purposes with at least one positive anti-β(2)GPI isotype. A laboratory database search identified patients who had undergone anti-β(2)GPI testing during a 3 year period. Medical records of patients with a positive anti-β(2)GPI result were reviewed and clinical events ascertained. Thromboses were subdivided into provoked and unprovoked, depending on the stated aetiology. A total of 128 patients had at least one positive anti-β(2)GPI isotype. There was a higher proportion of unprovoked thromboses among patients who were IgG anti-β(2)GPI positive compared to those who lacked IgG anti-β(2)GPI (20/30 versus 20/98). Median IgG anti-β(2)GPI levels were higher among patients with unprovoked events compared to those without (22.5 SGU versus 2 SGU). Retrospective assessment of anti-β(2)GPI testing strategies showed that testing IgM and/or IgA anti-β(2)GPI after IgG anti-β(2)GPI captured a greater number of non-thrombotic events and provoked thromboses than unprovoked thromboses. IgG anti-β(2)GPI associates most strongly with clinical events characteristic of antiphospholipid syndrome (APS). These results suggest that IgG anti-β(2)GPI is superior to IgM and IgA anti-β(2)GPI in the assessment of hospital patients with potential APS.
authors.affiliation: 1PathWest and Department of Clinical Immunology, Fremantle Hospital, Fremantle 2PathWest and Department of Clinical Immunology, Sir Charles Gairdner Hospital, Nedlands 3School of Pathology and Laboratory Medicine, University of Western Australia, Perth, WA, Australia.
authors.forename: Anna
authors.initials: A
authors.lastname: Brusch
authors.forename: Christine
authors.initials: C
authors.lastname: Bundell
authors.forename: Peter
authors.initials: P
authors.lastname: Hollingsworth
mesh_terms: D000328:Adult; D000368:Aged; D017152:Antibodies, Antiphospholipid / Q000276:immunology*; D016736:Antiphospholipid Syndrome / Q000175:diagnosis* / Q000276:immunology; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology*; D007132:Immunoglobulin Isotypes / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013927:Thrombosis / Q000276:immunology*; D053482:beta 2-Glycoprotein I / Q000276:immunology*
chemical_list: D017152:Antibodies, Antiphospholipid; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007075:Immunoglobulin M; D053482:beta 2-Glycoprotein I