Consistent with the anti-inflammatory and immunomodulatory activities observed in vitro (Fig. 1, Fig. 3f,g), levels of human inflammatory cytokines, including IL-2, TNF-α, and interferon (IFN)-γ, in blood samples of GVHD mice were more effectively reduced by injection of SHC-MSCs or PLK1-overexpressing MSCs than by injection of naïve MSCs (Fig. 4f). The gene discussed is PLK1; the disease is graft versus host disease.