Abstract
Inhibitor development is a serious complication of hemophilia A treatment. Although studies of inhibitor prevalence had been published earlier,1–3 the possibility that there is increased risk of inhibitor formation with different Factor VIII (F.VIII)-containing products was first raised when heat-treated concentrates were introduced. However, this concern was quickly dropped when it was apparent that heat treatment was necessary to inactivate HIV. As a result, no systematic study during the 1980s directly compared heat treated and non-heat treated F.VIII concentrates.