Therefore, we tested the phenotype alteration of CD4+ and CD8+ T cells in the presence of IL-7 and IL-15 (data is not shown), it is displayed that the terminal cells increased and naïve subtype decrease when PBMC were treated with both IL-7 and IL-15 simultaneously, the effect of IL-7 was overlapped by IL-15, which may partly explain why a lower naïve T cell was detected in MDS patients although no abnormal plasma IL-7 level is observed. The gene discussed is IL15; the disease is myelodysplastic syndrome.