UM171 enhances CD34⁺transduction efficiency with FVIII. (A) FC analysis of FVIII overexpression in CD34⁺ cells transduced with LV-hPGK-hBDDFVIII. Representative FC plots are shown on the right at 50, 100, and 200 MOI. On the left, the gating strategy on CD34⁺ cells and the IgG isotype control for FVIII staining are displayed. (B) Collective analysis of FVIII expression in CD34⁺ cells transduced with LV-hPGK-hBDDFVIII (n = 5, mean ± standard error the mean [SEM]). (C) FVIII expression in total CD34⁺ cells after 7 to 10 days of culture or transduction at different MOI with or without 38 nM UM171 (added every 2 days) (n ≥ 5, mean ± SEM). (D) Rate of FVIII⁺/CD34⁺ cells, calculated by multiplying FVIII percentage and CD34 percentage as per the following equation (percentage of FVIII × percentage of CD34⁺ cells) per 100 (mean ± SEM, n > 5). (E) CD34⁺ CFU colonies after 14 days (n = 3, mean). UT, untransduced.