CEACAM1 and graft versus host disease: In experiments comparing recipients of WT and Ceacam1-Tg T cells on day 21 post-transplant, we found that recipients of Ceacam1-Tg T cells demonstrated significantly less GVHD of the liver, intestines, and thymus compared to recipients of WT T cells, but similar skin GVHD (Figures 2D–F).