Elevated levels of CD4⁺ T cells in HIS-SGM3 mice. Twelve weeks after human CD34⁺ HSC engraftment, HIS and HIS-SGM3 mice were analyzed for human CD4⁺ to CD8⁺ T-cell ratios in blood (A), bone marrow (BM) (B), spleen (C), and liver (D). (E) Original fluorescence-activated cell sorter plots. Cells were gated on human CD45⁺CD3⁺ T cells. Unpaired Student t test: *P ≤ .05; **P ≤ .005; ***P ≤ .0001.