We first performed coculture of in vitro AML-activated BM ST2+ Treg cells or non-activated ST2− Treg cells with BM leukemic CD8 T cells stained with SYTOX, a high-affinity nucleic acid that penetrates cells with compromised plasma membranes, in the presence or not of IL-33 and with or without a specific inhibitor of GZMB, Z-AAD-CMK. This evidence concerns the gene IL33 and acute myeloid leukemia.