Anti-protein C antibodies are associated with resistance to endogenous protein C activation and a severe thrombotic phenotype in antiphospholipid syndrome.
J Thromb Haemost
; 12(11): 1801-9, 2014 Nov.
Article
en En
| MEDLINE
| ID: mdl-25196808
ABSTRACT
BACKGROUND:
Antiphospholipid antibodies may interfere with the anticoagulant activity of activated protein C (APC) to induce acquired APC resistance (APCr).AIMS:
To investigate the frequency and characteristics of APCr by using recombinant human APC (rhAPC) and endogenous protein C activation in antiphospholipid syndrome (APS).METHODS:
APCr was assessed in APS and non-APS venous thromboembolism (VTE) patients on warfarin and normal controls with rhAPC or Protac by thrombin generation. IgG anti-protein C and anti-protein S antibodies and avidity were assessed by ELISA.RESULTS:
APS patients showed greater resistance to both rhAPC and Protac than non-APS patients and normal controls (median normalized endogenous thrombin potential inhibition) APS patients with rhAPC, 81.3% (95% confidence interval [CI] 75.2-88.3%; non-APS patients with rhAPC, 97.7% (95% CI 93.6-101.8%; APS patients with Protac, 66.0% (95% CI 59.5-72.6%); and non-APS patients with Protac, 80.7 (95% CI 74.2-87.2%). APS patients also had a higher frequency and higher levels of anti-protein C antibodies, with 60% (15/25) high-avidity antibodies. High-avidity anti-protein C antibodies were associated with greater APCr and with a severe thrombotic phenotype (defined as the development of recurrent VTE while patients were receiving therapeutic anticoagulation or both venous and arterial thrombosis). Twelve of 15 (80%) patients with high-avidity anti-protein C antibodies were classified as APS category I.CONCLUSION:
Thrombotic APS patients showed greater APCr to both rhAPC and activation of endogenous protein C by Protac. High-avidity anti-protein C antibodies, associated with greater APCr, may provide a marker for a severe thrombotic phenotype in APS. However, in patients with category I APS, it remains to be established whether anti-protein C or anti-ß2 -glycoprotein I antibodies are responsible for APCr.Palabras clave
Texto completo:
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Base de datos:
MEDLINE
Asunto principal:
Proteína C
/
Síndrome Antifosfolípido
/
Anticuerpos Antifosfolípidos
/
Resistencia a la Proteína C Activada
/
Tromboembolia Venosa
Tipo de estudio:
Diagnostic_studies
/
Observational_studies
/
Prevalence_studies
/
Risk_factors_studies
Idioma:
En
Revista:
J Thromb Haemost
Asunto de la revista:
HEMATOLOGIA
Año:
2014
Tipo del documento:
Article