GVHD reduces tissue stem cells in the skin and lingual epithelium and impairs hair and skin regeneration. Lethally irradiated B6 or B6-Lgr5^EGFP-cre/ER mice were transplanted as in Figure 1. Back skins from B6-Lgr5^EGFP-cre/ER recipients were harvested on day +14 after SCT. (A) Representative immunofluorescent images of EGFP (green), CK15 (red), and DAPI (blue). Original magnification ×40. Scale bar, 25 μm. Numbers of Lgr5⁺CK15⁺ (B) and Lgr5⁻CK15⁺ (C) cells per hair follicle from 2 independent experiments (n = 6-8 per group). (D) The numbers of Lgr5⁺ HFSCs (n = 5-6 per group) and (E) infiltrating T cells in the back skin (n = 4-6 per group) on day +7, +14, +21 after SCT from 2 independent experiments. (F) Immunofluorescent staining of CK15 (red) and DAPI (blue) in lingual sections on day +7. Original magnification ×20. Scale bar, 50 μm. (G-H) Representative images of immunofluorescent staining with anti-SOX9 (G) or anti-Ki-67 (H) mAbs (red) with DAPI (blue) in the skin samples harvested on day +35 after SCT. Original magnification ×10. Scale bar, 100 μm. (I-J) Numbers of hair follicles from independent 2 experiments (I, n = 8-9 per group) and macroscopic images of recipient mice (J) on day +35 after SCT. (K-M) Full-thickness round skin was removed from the shaved back of B6-Lgr5^EGFP-cre/ER × R26^tdTomato mice after Cre recombination with tamoxifen treatment after SCT. (K) Representative immunofluorescent images of tdTomato (red), and DAPI (blue) 12 days after incision. The regenerated epithelium was marked with double-headed arrows and dot lines show epidermal-dermal junction. Original magnification ×20. Scale bar, 50 μm. Macroscopic images (L) and relative wound area (M) from 2 independent experiments were combined (n = 6 per group). The Mann-Whitney U test or 1-way ANOVA followed by the Tukey posttest was used to compare the data (**P < .01; ***P < .005). Data represent the mean ± SEM. dpw, days postwounding.