Our data showing decreased numbers of donor Tregs associated with significantly reduced expression of the intracellular foxp3 transcription factor in CD4+ T cells in the spleen of allo-HSCT recipients (Fig 5) is consistent with previously published clinical data demonstrating that allo-HSCT patients with GvHD had decreased Tregs in blood compared with patients treated with either allo-HSCT recipients without GvHD or auto-HSCT recipients [48]. This evidence concerns the gene FOXP3 and graft versus host disease.