FOXP3 and graft versus host disease: We would note that instability of Foxp3 expression has also been noted to occur in nTreg cells in non-transplant models (Zhou et al., 2009; Pillai et al., 2011) as well as in GVHD (Laurence et al., 2012), where these cells can revert to a proinflammatory phenotype under inflammatory conditions.