Reduced inflammatory cytokines and increased FoxP3⁺T_regcells in the colons of AhR^−/−T-cell recipients. Cytokine levels were determined using an enzyme-linked immunosorbent assay of colon homogenates 7 days after transplant (A) (n = 3-4 for WT; n = 4-5 for AhR^−/−; representative experiment of 2 independent experiments) and 14 days after transplant (B) (n = 4-5 for WT; n = 4 for AhR^−/−). Representative experiments of 2 independent experiments. (C) Colon histopathology score 20 days after transplant; n = 9 for WT, and n = 18 for AhR^−/−. Pooled results from 2 independent experiments. (D) Colons were isolated and digested as described in “Materials and methods.” Lymphocytes from the colon underwent intranuclear FoxP3-staining as described in “Materials and methods” prior to analysis. N = 12 for each group; pooled results from 3 independent experiments. (E) Representative images of immunohistochemistry staining done on colon samples used for colon GVHD score evaluation. *P < .05; **P < .001 as indicated by Student t test. H&E, hematoxylin and eosin.