Fig 2 The pathogenesis of celiac disease involves a triad of predisposing genes (HLA-DQ2 and HLA-DQ8 haplotypes), dietary gluten, and other less well defined environmental factors. Innate and adaptive immune responses to gluten fragments at the small intestinal epithelium result in characteristic autoantibodies, histologic changes (intraepithelial lymphocytosis and villous atrophy), and clinical symptoms (such as diarrhea or iron deficiency anemia). Adapted, with permission, from Green and colleagues⁴⁹