Complement activity and complement regulatory gene mutations are associated with thrombosis in APS and CAPS.
Blood
; 135(4): 239-251, 2020 01 23.
Article
em En
| MEDLINE
| ID: mdl-31812994
ABSTRACT
The antiphospholipid syndrome (APS) is characterized by thrombosis and/or pregnancy morbidity in the presence of antiphospholipid antibodies, including anti-ß2-glycoprotein-I (anti-ß2GPI), that are considered central to APS pathogenesis. Based on animal studies showing a role of complement in APS-related clinical events, we used the modified Ham (mHam) assay (complement-dependent cell killing) and cell-surface deposition of C5b-9 to test the hypothesis that complement activation is associated with thrombotic events in APS. A positive mHam (and corresponding C5b-9 deposition) were present in 85.7% of catastrophic APS (CAPS), 35.6% of APS (and 68.5% of samples collected within 1 year of thrombosis), and only 6.8% of systemic lupus erythematosus (SLE) sera. A positive mHam assay was associated with triple positivity (for lupus anticoagulant, anticardiolipin, and anti-ß2GPI antibodies) and recurrent thrombosis. Patient-derived anti-ß2GPI antibodies also induced C5b-9 deposition, which was blocked completely by an anti-C5 monoclonal antibody, but not by a factor D inhibitor, indicating that complement activation by anti-ß2GPI antibodies occurs primarily through the classical complement pathway. Finally, patients with CAPS have high rates of rare germline variants in complement regulatory genes (60%), compared with patients with APS (21.8%) or SLE (28.6%) or normal controls (23.3%), and have mutations at a rate similar to that of patients with atypical hemolytic uremic syndrome (51.5%). Taken together, our data suggest that anti-ß2GPI antibodies activate complement and contribute to thrombosis in APS, whereas patients with CAPS have underlying mutations in complement regulatory genes that serve as a "second hit," leading to uncontrolled complement activation and a more severe thrombotic phenotype.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Trombose
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Síndrome Antifosfolipídica
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Ativação do Complemento
Tipo de estudo:
Risk_factors_studies
Limite:
Adult
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Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article