Adenosine activates caspase pathways leading to the release of the bioactive form of IL-1β during acute GVHD (Deaglio et al., 2007; Tsukamoto et al., 2012; Wilhelm et al., 2010), whereas IL-33 and its receptor ST2 (also known as IL1RL1) have been promising targets for multiple autoimmune disorders (Reichenbach et al., 2015; Zeiser and Blazar, 2017; Zhang et al., 2015). This evidence concerns the gene IL1RL1 and acute graft versus host disease.