Portal de Periódicos da CAPES

How factor VIIa works in hemophilia

2003; Elsevier BV; Volume: 1; Issue: 6 Linguagem: Inglês

10.1046/j.1538-7836.2003.00181.x

1538-7933

Saulius Butenas, K. Brummel, Beth A. Bouchard, Kenneth G. Mann,

Platelet Disorders and Treatments

SummaryThe influence of elevated platelet concentration and recombinant factor VIIa (rFVIIa) on thrombin generation at 5 pM tissue factor (TF) in a synthetic mixture corresponding to hemophilia B (SHB) and ‘acquired’ hemophilia B blood (AHBB) produced in vitro by an antifactor IX antibody was evaluated. (a) Thrombin generation in SHB and AHBB was delayed and reduced; (b) with 10 nM rFVIIa or 5× normal platelets (10 × 108/mL) SHB and AHBB showed a slight increase in thrombin generation; (c) in the absence of TF, almost no thrombin generation was detected in SHB and AHBB in the presence of 10 nM rFVIIa and 10 × 108/mL activated platelets (5× normal); (d) with TF, 10 nM rFVIIa and 3–5× normal nonactivated platelets (6–10 × 108/mL), thrombin levels approaching normal values were attained. FVIIa appears to function effectively and locally by the combined effect of TF expression and platelet accumulation at the site of a vascular lesion. The influence of elevated platelet concentration and recombinant factor VIIa (rFVIIa) on thrombin generation at 5 pM tissue factor (TF) in a synthetic mixture corresponding to hemophilia B (SHB) and ‘acquired’ hemophilia B blood (AHBB) produced in vitro by an antifactor IX antibody was evaluated. (a) Thrombin generation in SHB and AHBB was delayed and reduced; (b) with 10 nM rFVIIa or 5× normal platelets (10 × 108/mL) SHB and AHBB showed a slight increase in thrombin generation; (c) in the absence of TF, almost no thrombin generation was detected in SHB and AHBB in the presence of 10 nM rFVIIa and 10 × 108/mL activated platelets (5× normal); (d) with TF, 10 nM rFVIIa and 3–5× normal nonactivated platelets (6–10 × 108/mL), thrombin levels approaching normal values were attained. FVIIa appears to function effectively and locally by the combined effect of TF expression and platelet accumulation at the site of a vascular lesion.