DNMT1 and graft versus host disease: We recently showed that epigenetic interventions using azacitidine, a DNA methyltransferase 1 (DNMT1) inhibitor, mitigates GvHD and preserves the GvL effect after murine allo-HCT through the in vivo induction of regulatory T cells[4] and the selective inhibition of donor effector T cell proliferation compared to donor regulatory T cells in vivo[5].