development of inhibitor to factor viii is the most serious complication of hemophilia therapy. to determine the prevalence of inhibitors in iran hemophilia a patients exposed to blood products, 1280 hemophilia a patients (age range 9 months-84 years) were evaluated. all patients received several blood products such as fresh frozen plasma (ffp), cryoprecipitate, and factor viii. 635 of 1280 pat...