A good example of the importance of STAT3 can be seen in the differentiation of Th17 cells observed in patients suffering from Job’s syndrome (also known as hyperimmunoglobulin E syndrome (HIES)), which is a primary immune deficiency disorder characterized by chronic mucocutaneous candidiasis and recurring pneumonia caused by Candida albicans and Staphylococcus aureus, respectively [13]. This evidence concerns the gene STAT3 and hyper-IgE syndrome.