Several subsets of regulatory T cells have the ability to suppress the proliferation and function of autoreactive T cells and prevent type 1 diabetes development, including naturally occurring and induced populations of CD4+CD25+FoxP3+ T cells, CD8+ treg cells, NK T cells and CD4−CD8− (double-negative, DN) T cells [9–13]. Here, CD4 is linked to type 1 diabetes mellitus.