Donors (OR=0.56; 95%CI, 0.32–0.98; P=0.04) and recipients (OR=0.73; 95%CI, 0.63–0.85; P<0.0001) with TGF-β1 rs1800469 polymorphism showed decreased GVHD risk, respectively. The gene discussed is TGFB1; the disease is graft versus host disease.