Nevertheless, in patients with T1D or skin allografted mice, the low-dose IL-2 treatment post the adoptive transfer of polyclonal Tregs although it increased the frequency of circulating Tregs, led to only limited therapeutic benefit [41,216], probably due to the inferior in vivo performance of polyclonal Tregs over antigen-specific Tregs, as discussed earlier. This evidence concerns the gene IL2 and type 1 diabetes mellitus.