For example, upregulation of miR-181d leads to CD4+CD8+ T cell developmental disorder while also reducing the number of CD4+CD8+ T cells and increasing stress-induced thymic atrophy, but only a slight decrease in peripheral T cells was observed in mice after miR-181d transfection (Belkaya and van Oers, 2014). This evidence concerns the gene CD4 and thymus atrophy.