Clinical validation of Factor VIII allo-antibody assays
in patients with hemophilia A.
The correlation of factor VIII antibodies, measured with different assays, on factor VIII survival in patients with severe haemophilia A.

Inclusion criteria for patients with severe hemophilia A without inhibitors:
1) Phenotype less than 1% factor VIII activity
2) No history of an inhibitor
3) Normal response to Factor VIII infusion during bleeding episodes
4) Normal recovery
5) No recent change in bleeding pattern
6) No Factor VIII infusion for minimally 72 hours before start of the study.;Inclusion criteria for patients with severe hemophilia A with inhibitor or at high risk of having an inhibitor:
1) Phenotype less than 1% factor VIII activity
2) Diminished response to Factor VIII compared to past performance,
Or: Low recovery
Or: More frequent bleedings and/or a different bleeding pattern
Or: higher need for Factor VIII substitution than before
3) No factor VIII infusion for minimally 72 hours before start of the study

Exclusion criteria for severe hemophilia A patients with or without Factor VIII inhibitors:
1) Known allergy to plasma proteins
2) Fever (higher than 38 °C)
3) Clinical indication of liver cirrhosis (echo graphic indication, enlarged spleen, enlarged liver, decreased platelet count, elevated ALAT/ ASAT levels
4) Hepatitis C recently treated with interferon (washout 6 months)
5) HIV positive
6) Medication:
NSAIDs (non-steroid anti-inflammatory drugs)
Ascal
Clopidogrel
Antimicrobial medication
Thyroid inhibitors
Selective serotonin re-uptake inhibitors.
7) Hb levels less than 8.0 mmol/l
8) Platelet counts less than 50*109/ltr