Indeed, ex vivo T-cell depletion from the graft reduces dramatically the incidence of GVHD even without post-grafting immunosuppression [9] At the cellular level, donor T cells are mainly activated by recipient antigen-presenting cells (APCs) through the recognition of MHC-associated peptides presented by APCs by the T-cell receptor (TCR) of T cells. Here, HLA-C is linked to graft versus host disease.