[Factor VIII:C activity during heat inactivation of viruses in cryoprecipitates]

The transmission of HIV by Factor VIII concentrates is the cause of AIDS in hemophiliacs. The yield of Factor VIII in the concentrate depends on the purification level and the applied inactivation procedure of viruses. Because of the high concentration of fibrinogen and the other proteins in cryoprecipitate, heat inactivation of the lyophilized cryoprecipitate leads to a substantial loss of Factor VIII:C, a change of color and the loss of solubility. With the addition of the buffer solution, which stabilizes Factor VIII, lyophilized cryoprecipitate can be heat treated at 60 degrees C through 72 hours with a loss of 15% of the activity of Factor VIII. This procedure inactivates more than 10(5) of Sendai viruses in 24 hours and more than 10(6) of Newcastle viruses in 72 hours in 1 ml of cryoprecipitate. The yield of F VIII:C in cryoprecipitate is about 440 u/L of fresh frozen plasma, which is acceptable. Heat inactivated, lyophilized cryoprecipitate, therefore, should be the product of choice for the countries with a small number of donors and a shortage of fresh frozen plasma.