The largest current research project in our lab is entitled "Race-Based Mechanisms of Factor VIII Immunogenicity in Hemophilia". We are now in the final year of this study. T-cell and B-cell responses to FVIII are being investigated using blood samples from a large number of hemophilia A blood donors. The methods described above are being applied to answer the question of why immune responses develop in hemophilia A patients with Black African ancestry much more frequently than in Caucasian patients with similar disease-causing mutations. Identifying reasons for this discrepancy will hopefully lead, eventually, to more effective treatments for hemophilia A patients. We have identified several T-cell and B-cell epitopes in FVIII and are now designing FVIII variants that will be less immunogenic in specific subsets of haemophilia A patients. This work is also being carried out with funding from a Pfizer "ASPIRE" hemophilia award. We gratefully acknowledge unrestricted research support received over the past 5 years from foundations at Bayer and CSL Behring, Inc., as well as start-up funds from the Puget Sound Blood Center.