The Preparation and Assay of a Christmas‐Factor (Factor IX) Concentrate and its Use in the Treatment of Two Patients

SINCE Christmas factor (Factor IX) is relativcly stable aiid is not used up during coagulation, it might have bcen expected that blood or plasnia transfusions would have bcen more cffective in Christmas disease than they are in the treatment of patients with classical haemophilia (Factor VIII-deficiency). This is not thc casc ; Christmas-disease patients havc bled as much as, or more than, hacmophilic patients after tooth extraction, and frcsh plasma has been ineffective in raising the blood level of Christmas factor. For these reasons the provision of a concentrated material for the treatmciit of Christmas-disease patients seemed iieccssary. An attempt was made to prepare this material from fresh human plasma by a modification of the method of Didisheim, Loeb, Blatrix and Soulier (1959). Early in this work it was clear that the loss of activity during purification was great and that large amounts of blood would be required even for the treatment of a single patient. For this reason attention was directed to the recovery of Christmas factor from the residual material derivcd from the plasma fractionation process of the Blood Products Laboratory of the Lister Institute. The present paper describcs a concentratc prepared from this, and its use during the successful operative treatment of two patients.