Not surprisingly, humans with HIES (who have mutations in STAT3) have a higher than normal percentage of cells that bear the phenotype of Tregs (50), while mice deficient in the IL-2 signaling cascade (notably IL-2 or STAT5) have a reduction in Tregs and an excess of Th17 cells in association with autoimmune disease. This evidence concerns the gene IL2 and autoimmune disease.