Likewise, in a murine major histocompatibility complex-disparate GVHD model, this approach led to enhanced GVHD survival, the in vivo selective expansion of Tregs, and importantly, the maintenance of graft-versus-tumor (GVT) responses, whereas the adoptive transfer of ortho-hIL-2Rβ+ CAR T cells into immunodeficient mice bearing CD19+Nalm6 leukemia xenografts in combination with ortho-hIL-2 administration led to 1000-fold ortho-hIL-2Rβ+CAR T expansion and rescued the antileukemic effect of an otherwise suboptimal CAR T cell dose [220,221]. Here, CD19 is linked to graft versus host disease.