MHC class II deficiency within cDCs induces Treg deficiency and cGVHD. (A) Clinical scores of lethally irradiated B6D2F1 recipients transplanted with 5 × 10⁶ TCD BM cells with (BM+T) or without (TCD) 0.5 × 10⁶ CD3⁺ T cells from CD11c Cre^neg or I-A^b CD11c Cre^pos donor mice (n = 8, 1 experiment). (B) Representative images of H&E staining of skin taken at day 93 after BMT and GVHD histopathology scores quantified in the skin (n = 6-8, 1 experiment). (C) Representative dot plots of CD4⁺FoxP3⁺ cells gated on CD3⁺CD4⁺ T cells in spleen and thymus at day 94 after BMT. (D) Cell numbers, frequency, and absolute numbers of CD3⁺CD4⁺FoxP3⁺ Treg cells in spleen and thymus (n = 5-8, 1 experiment). (E) Lethally irradiated B6D2F1 recipients were transplanted with 5 × 10⁶ TCD BM cells from CD11c Cre^neg, I-A^b CD11c Cre^pos, or B6.H2-Ab1^−/− donor mice with 0.5 × 10⁶ FoxP3-luc⁺ CD3⁺ T cells. Representative images of the FoxP3-luc⁺CD3⁺ T cells are represented in the whole mice at day 23 after BMT. (F) The bioluminescence (BLI, ph s⁻¹ cm⁻² sr⁻¹) is represented and followed over time after BMT (n = 10, 2 experiments). Each dot corresponds to 1 individual mouse.