IL4 and epistaxis: Due to the major roles played by Th17 in the induction of inflammation, the present study aimed to assess the serum levels of Interleukin 17A (IL-17A) and IL-23, as the most important cytokines in the Th17 pathway, as well as IFN-, IL-4, and IL-10 serum levels, as regulatory cytokines for Th17 cells in patients with idiopathic epistaxis.