The largest study including data from 153 consecutive allogeneic transplant recipients given grafts after high-dose conditioning and ATG observed no correlation between IL-7 levels early after transplantation and acute GVHD, while, interestingly, there was an inverse correlation between IL-15 levels early after transplantation and grade II–IV acute GVHD [57]. The gene discussed is IL15; the disease is acute graft versus host disease.