Aggregation of human platelets by commercial preparations of bovine and porcine antihaemophilic globulin.

Infusion of commercial preparations of porcine and bovine antihaemophilic globulin into three haemophilic patients produced transient thrombocytopenia. This platelet-aggregating activity has been shown to be present in a wide range of animal plasmas and is related to the fibrinogen fraction. The mechanism of platelet aggregation by animal fibrinogen is discussed and some inhibitors of the reaction are described.