However, IL-25 is expressed by intestinal epithelial cells, endothelial cells, type 2 CD4+ (Th2) cells, natural killer T cells (NKT), FcεR1-ligated mast cells, and eosinophils, and thus could come from a variety of cell types during helminth infection [3,4,38,39,56,57,58,59]. The gene discussed is IL25; the disease is helminthiasis.