In allogeneic mouse models, one study by Wachsmuth and colleagues found lower doses of PTCy (10 mg/kg and 25 mg/kg) reduced GVHD, with the latter being superior in reducing GVHD mortality, decreasing alloreactive CD4+ and CD8+ T cells and increasing donor regulatory T cells (Tregs) compared with both lower (10 mg/kg) and higher (50–200 mg/kg) PTCy doses [19]. The gene discussed is CD4; the disease is graft versus host disease.