In celiac disease (CeD), interleukin 15 (IL-15) affects the epithelial barrier by acting on intraepithelial lymphocytes, promoting interferon γ (IFN-γ) production and inducing strong cytotoxic activity as well as eliciting apoptotic death of enterocytes by the Fas/Fas ligand system. This evidence concerns the gene FASLG and celiac disease.