Antigenic differences among bovine and porcine Factor VIII concentrates.

Three anti-Factor-VIII antibodies from hemophiliacs were reacted with samples of batches of Maws commerical bovine and porcine Factor VIII concentrates manufactured over a 12-year period. The apparent antibody concentrations varied widely with the different batches of concentrates. The variations are probably due to intrinsic differences in the antigenic nature of the Factor VIII in the different preparations. With the older porcine concentrates, the low apparent concentrations may be in part due to the reaction of antibody with inactive Factor VIII. When animal Factor VIII concentrates are used in treating hemophiliac patients who have anti-Factor-VIII antibodies, the least reactive batch should be chosen. Random batches of animal concentrates are not suited as a standard for measuring anti-Factor-VIII antibody concentration.