β-Globin to γ-globin switch in in vivo–transduced β-YAC/CD46 mice and hematological parameters. (A) Relative human β-globin (HBB) and γ-globin (HBG) mRNA levels in peripheral blood RBCs and bone marrow erythroid Ter-119⁺ cells. mRNA levels in untransduced mice were taken as 1.0. (B) Percentage of HBG mRNA of human HBB mRNA (untransduced, empty red squares; HDAd-HBG-CRISPR–transduced, blue squares). (C) HPLC data. Percentage of human Gγ- and Aγ-globin protein relative to human β-globin protein in RBCs from untransduced and HDAd-HBG-CRISPR mice (week 12 after transduction). (D-E). Hematological safety of in vivo HDAd-HBG-CRISPR genome editing. (D) Cellular composition in blood (CD3⁺, CD19⁺, Gr-1⁺), spleen (CD3⁺, CD19⁺, Gr-1⁺), and bone marrow (CD3⁺, CD19⁺, Gr-1⁺, Ter119⁺, LSK) at week 12 after in vivo transduction. Shown is the percentage of lineage marker–positive cells (CD3⁺, CD19⁺, Gr-1⁺, Ter119⁺ cells) and HSPCs (LSK cells). (E) Colony-forming potential of bone marrow Lin⁻ cells harvested at week 12 after in vivo HSPC transduction of β-YAC/CD46 mice. Number of colonies that formed after plating of 2500 Lin⁻ cells (left panel) and total number of cells pooled from colonies (right panel). Each point is an individual animal.