CD4+ regulatory T (Treg) and conventional T (Tcon) cells at 1 month after allo-HSCT. a Flow cytometric analysis of the patient who had undergone thymectomy prior to PBSCT. Both CD4+CD25high Treg cells and CD4+ Tcon cells were among the CD4+ cells detected by flow cytometry of peripheral blood mononuclear cells at 1 month after PBSCT. Treg cells expressed Foxp3 more abundantly than Tcon cells. b Comparisons in the proportions of CD4+CD25highFoxp3+ Treg cells and CD4+Foxp3− Tcon cells between young and old allo-HSCT recipients. Correlations between proportions of Treg cells (c) or Tcon cells (d) and ages of recipients or donors. The close circles indicate data of the thymectomized patient.