Carmen Escuriola Ettingshausen will investigate the neutralisation activity of FVIII antibodies in the plasma of inhibitor patients against FVIII concentrates and different batches of the same FVIII concentrate.
Concentrates manifesting a low level of reactivity with the inhibitor have better haemostatic effect in vivo.
Haemophilia A patients with relatively high amounts of FVIII light-chain antibodies in plasma might benefit from FVIII concentrates containing VWF(VWF:RCo / FVIII:C > 0.3), since VWF appears to have some protective effect on FVIII.
A modified New Oxford inhibitor assay is being used. Dilutions of test plasma will be incubated with standardised amount of FVIII concentrate and the residual FVIII:C will be measured. FVIII inhibitors will be quantitated in Oxford Units, which are derived from neutralising-mixing studies of patient test plasma with diluted FVIII concentrate.
- Berntop E et al. Variation in factor VIII inhibitor reactivity with different commercial factor VIII preparations. Haemophilia 1996; 2(2): 95-99.
- Suzuki T et al. Factor VIII inhibitor antibodies with C2 domain specificity are less inhibitory to factor VIII complexed with the von Willebrand factor. Thromb Haemost 1996; 76(5): 749-754.
- Kallas A and Talpsep T. VWF in FVIII concentrates protects against neutralisation by FVIII antibodies of heamophilia A patients. Haemophilia 2000; 7(4): 372-80.
- Sukhu K et al. Variation in inhibitor reactivity in aquired haemophilia A with different concentrates. Clin Lab Haematol 2000; 22(5): 287-90.
- Tagariello GL et al. In vitro reactivity of FVIII inhibitors with VWF in different commercial FVIII concentrates. Am J Hematol 2007; 82(6): 460-262.