The early finding that the immunosuppressive anti-GvHD drug sirolimus (rapamycin) exerts its effect through DC modulation (including modulation of maturation [39], macropinocytosis and endocytosis [40], antigen uptake [41], and signaling and apoptosis [42–44]) further emphasized the role of Dc in the GvHD response. This evidence concerns the gene DCX and graft versus host disease.