Correction by factor VIII of decreased neutrophil alkaline phosphatase activity in classic haemophilia and von Willebrand's disease.

Neutrophil alkaline phosphatase (NAP) score was estimated in ten patients with hereditary disorders in which antihaemophilic factor (factor VIII) is functionally deficient. NAP scores were estimated immediately before cryoprecipitate was administered, and following correction of patients' clinical condition and factor VIII activity in their plasma. While lower than normal NAP scores were observed before the treatment has been started, normal NAP score estimates were obtained following the successful correction of decreased procoagulant factor VIII (FVIIIC) activity in plasma of patients with classic haemophilia and von Willebrand's disease (vWd).