CD80 and graft versus host disease: In addition, the administration of WU5, WU8, and WU10 shows a significant trend towards reduction in GvHD by enhancing Tregs and immune reconstitution while suppressing both recipient- and donor-BM-derived APCs, as well as costimulatory protein CD80, on the BM-derived APCs compared to the vehicle control after allo-HCT.