Flow cytometry analyses performed at day 28 post-transplantation revealed a trend toward an increased proportion of Tregs in mice treated with UC-MSCs, while BM-MSC therapy was associated with an increased proportion of IL10+ lymphocytes, but also a trend toward an increased proportion of Th17 cells [whose role in xenogeneic GVHD in humanized mouse models is increasingly demonstrated (37, 64)] and IFNγ+CD8+ cells. This evidence concerns the gene IL10 and graft versus host disease.