HIS-SGM3 mice show increased levels of myeloid DCs and decreased levels of primary HSCs in the bone marrow. Bone marrow–derived leukocytes from HIS and HIS-SGM3 mice were stained for the expression of human CD45, CD123, CD11c, CD1c (BDCA-1), BDCA-4, HLA-DR, and CD86 to analyze the development of human DCs. (A) Representative fluorescence-activated cell sorter plots demonstrate the presence of CD123⁺ plasmacytoid DCs and BDCA-3⁺ or BDCA-1⁺ myeloid DCs in HIS mice. (B) Histogram shows CD11c expression on CD123⁺ (light gray outline), BDCA-4⁺ (black outline), and BDCA-1⁺ (shaded area) DCs. (C) Frequencies of CD1c⁺ (BDCA-1⁺) myeloid DCs. (D) Original fluorescence-activated cell sorter dot plots. (E) Histograms show CD86 and HLA-DR expression on CD1c⁺ myeloid DCs in HIS mice (shaded area) and HIS-SGM3 mice (black outline) compared with isotype control (light black outline). To compare the maintenance of primary human HSCs in the bone marrow of HIS and HIS-SGM3 mice, human leukocytes were analyzed for the expression of CD34, CD38, c-KIT, and CD133. (F) Group data of human CD34⁺CD38-c-KIT⁺ HSC frequencies. Unpaired Student t test: **P ≤ .005