Critically, because antigen recognition by NKT cells is CD1d-restricted rather than MHC-restricted, their intrinsic alloreactive potential is minimal; correspondingly, they are associated with a reduced risk of graft-versus-host disease (GvHD) in the setting of allogeneic hematopoietic stem-cell transplantation (84). The gene discussed is CD1D; the disease is graft versus host disease.