We have tested in vivo the FOXP3+CD8+ Tregs induced in the 14-day ex vivo expansion in a model of xenogeneic GVHD in immune-humanized mice, and we have observed a similar protective potential of the Tregs compared to what we have previously demonstrated using polyclonally expanded CD8+ Tregs (14). Here, FOXP3 is linked to graft versus host disease.