In other studies (126), baricitinib, a best-in-class Jak1/2 inhibitor, blunted IFNγR and IL6R signaling, resulting in complete protection from GVHD lethality as well as the reversal of active GVHD prevents GVHD with 100% survival, and reverses ongoing GVHD with dramatically increased Tregs along with decreased Th1 and Th2 differentiation, MHC class II and B7 ligand expression on APCs (126). This evidence concerns the gene IFNGR1 and graft versus host disease.