TgRhoA mice develop hematopoietic cell-dependent autoimmunity. (A) Gross findings demonstrating fibrosis of ears and tail (red arrowheads) of mice from the indicated genotypes (top). Hematoxylin and eosin (H&E) staining of mouse tail tips demonstrating a polymorphonuclear cell infiltrate (white arrowheads) and immunohistochemistry of CD4-positive cells (bottom). Scale bars, 100 μm. (B) Percentage of CD4/TCRβ and CD11b/Ly6G cells among CD45⁺ hematopoietic cells recovered from tail skin. (C) Mean fluorescence intensity of RORγt expression in tgRhoA CD4⁺ cells compared with isotype control (P = .0076). (D) H&E staining of tail tips from congenic recipient mice 10 weeks after injection with WT or tgRhoA bone marrow. Scale bars, 100 μm. (E) Flow cytometric analysis of bone marrow donor (CD45.1⁻) CD11b⁺ cells. (F) Flow cytometric analysis of bone marrow donor (CD45.1⁻) CD4⁺ cells in spleen or recovered from tail skin. (G) Representative flow cytometric profiles of splenic CD4⁺ naive and activated (top) or T_reg populations (bottom) along with quantification. Plots and graphs are representative of 3 experiments. (H) Expression of activation markers from sorted CD4⁺CD62L⁺CD44⁻CD25⁻-naive T cells 48 hours after mixed leukocyte reaction of tgRhoA-OT-II or WT-OT-II T cells unstimulated, stimulated with 5 μg/mL OVA₃₂₃-₃₃₉ peptide, or stimulated with PMA/Ionomycin. Data are representative of 2 independent experiments. All P values calculated by t test with Welch’s correction.