Surprisingly, we also observed significant increase of CD3+CD4-CD8- double negative T (DNT) cells in the liver, lung and colon of GVHD mice treated with i35-Bregs and this tissue-resident Treg subpopulation has recently been shown to suppress the severity of GVHD and other immune disorders 34, 68, 69. Here, CD4 is linked to graft versus host disease.