TAC1 and celiac disease: Our review process and literature search was based on the use of the following key words: gluten, gliadin, celiac disease, asymptomatic celiac disease, gluten and transglutaminase, gluten and exorphins, gluten and intolerance, gluten and DPP IV, gluten and substance P, DPP IV, gluten and neoantigens, celiac disease and epidemiology, and gluten-free diet.