When introduced with this genetic construct, the drug ganciclovir is converted to bear a triphosphate, leading to DNA chain termination and death of the cell expressing the suicide gene.89 Lymphocyte and hematopoietic stem cell transduction with HSV-TK and ganciclovir administration has been demonstrated to reduce toxicities, such as graft vs. host disease (GVHD),90,91 and eliminate CAR and HSV-TK-transduced cell populations in a ganciclovir dose-dependent fashion,92 highlighting the potential of the HSV-TK suicide gene to reduce CRS. The gene discussed is TKT; the disease is graft versus host disease.