IL9 and helminthiasis: The role of IL-9 in helminth infection was first suggested by animal studies in which IL-9 transgenic mice infected with Trichuris muris or Trichinella spiralis showed increased Th2 response and faster expulsion of the parasite from the intestine [16,37,38].Furthermore, a recent report also suggested that IL-9 plays important roles in promoting ILC2 survival and function in helminths-induced lung inflammation [39,40].