Autosomal dominant STAT3 loss-of-function mutations, characteristic of STAT3 hyper-IgE syndrome (STAT3-HIES), and autosomal recessive DOCK8 deficiency are prototypical IEIs presenting with elevated eosinophil counts and elevated serum IgE levels (43, 44). The gene discussed is STAT3; the disease is hyper-IgE syndrome.