Can Treg therapy prevent GVHD?

In this issue of Blood, Brunstein and colleagues report the results of the first study to test the safety of human umbilical cord blood– derived regulatory T cells (Tregs), an approach designed to decrease graft-versus-host disease.1 Transplanters, like Sisyphus of myth, have struggled mightily with trials of pharmacologic immunosuppressive drugs—we roll the rock up the mountain, only to see it roll back, leaving us where we began. This struggle has now led us to seek cellular therapies as a promising alternative.