FVIII replacement after BM transplantation. (A) Plasma FVIII antigen levels in groups of hemophilia A mice 2, 4, and 6 months after transplantation of 2 × 10⁶ BM cells from GFP transgenic donors. (B) Correlation between plasma FVIII antigen and FVIII activity (FTGT) levels in hemophilia mice 4 and 6 months after transplantation of 10 × 10⁶ BM cells, where both datasets were available for comparison. (C) Verification of plasma FVIII activity by aPTT in selected mouse plasma samples positive with FTGT assays 6 months after BM transplants. Mouse plasma FVIII activity and antigen level of 100% represented 1.02 IU/mL (FTGT), 1.04 IU/mL (aPTT), and 0.86 IU/mL (FVIII antigen assay) of human FVIII standard.