Antibodies to β2-glycoprotein I—a specific marker for the antiphospholipid syndrome |
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Authors: | J GUERIN C FEIGHERY R B SIM and J JACKSON |
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Institution: | Department of Immunology, St James'' Hospital, Dublin, Ireland;*MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford, Oxford, UK;†Department of Immunology, St James'' Hospital and The Dublin Institute of Technology, Dublin, Ireland |
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Abstract: | The antiphospholipid syndrome is a disorder characterized by recurrent thrombosis and the presence of antibodies specific to phospholipids. However, the diagnosis of this syndrome is hampered by the lack of a specific laboratory test. In this study an ELISA for the measurement of antibodies to solid-phase β2-glycoprotein I (β2-GPI) was established and compared with anticardiolipin antibodies for diagnosis of antiphospholipid syndrome. Significantly elevated levels of antibodies to β2-GPI were found in all patients with definite antiphospholipid syndrome (median = 91 AU). Marginally elevated levels of antibodies to β2-GPI were observed in 5% of patients with systemic lupus erythematosus (SLE; median = 4 AU), 1% with stroke (median = 3 AU), 13% with infectious mononucleosis (median = 3 AU), 10% with HIV infection (median = 3 AU) and 8% with VDRL false-positive serology for syphilis (median = 4 AU), but not in patients with rheumatoid factor, syphilis or carotid artery stenosis. In contrast, significantly raised levels of anticardiolipin antibodies were observed in 100% of patients with definite antiphospholipid syndrome, 30% with SLE, 88% with HIV infection, 94% with syphilis, 62% with infectious mononucleosis, 9% with rheumatoid factor-positive sera, 74% VDRL false-positive serology for syphilis, 47% with stroke and 0% with carotid artery stenosis. This solid-phase assay for antibodies to β2-GPI is highly specific for the antiphospholipid syndrome and represents an advance in the laboratory diagnosis of this disorder. |
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Keywords: | β2-glycoprotein I antiphospholipid syndrome ELISA cardiolipin thrombosis |
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