Abstract
A number of investigations were made in a hemophiliac who had become refractory to treatment with whole blood, plasma and plasma fractions. This refractoriness was traced to the presence of a circulating anticoagulant. By fractionation of the plasma it was determined that the anticoagulant was associated with the pseudoglobulin fraction of the plasma, and acted by inhibiting the action of antihemophilic globulin (coagulation globulin) present in natural blood. The antihemophilic globulin, however, was not physically altered by the anticoagulant and could be reprecipitated without loss of its antihemophilic properties.
The anticoagulant did not inhibit prothrombin, thromboplastin, or fibrinogen. It was unrelated to the lipid antithromboplastin or to heparin and did not appear to be an antibody.
