TGFB1 and graft versus host disease: Figure 2 shows that neither the blockade of TGF-β signaling following administration of ALK5i nor the depletion of NK cells from human PBMCs before cell transfer altered the course of GvHD as compared with control mice. On the other hand, a 15-day course of treatment with NPs encapsulating TGF-β and IL-2 provided sustained protective effects, since 75% of the mice in the NP-treated group were alive by day 50 vs. 25% of the control group treated with empty NPs (Figure 3A).