SLE PBMCs stimulated with IL-2 upregulated the expression of CD25, Foxp3, and Bcl-2 in Treg cells and the frequency of CD25hi Treg cells and promoted proliferation of CD3−CD56+ NK cells and expression of Bcl-2 in NK cells and in CD3+CD56+ natural killer T (NKT) cells (143). This evidence concerns the gene FOXP3 and systemic lupus erythematosus.