CD4 and graft versus host disease: Despite the small portion of DNTs in peripheral lymphocytes, it had been demonstrated that DNTs have strong suppressive ability towards CD8+ T cells, CD4+ T cells, B cells and NK cells in vitro and in vivo, which leads to xenograft or allograft transplantation tolerance and powerful prevention of GVHD (graft-versus-host disease) [23, 24].