In genetically  predisposed individuals, ingestion of cereal  prolamins can lead  to an immune-driven enteropathy known as celiac disease (CD). Despite a better understanding of pathogenesis of CD gained in recent years, the reason why wheat, barley and rye prolamins do trigger CD while gluten proteins from other cereals ( maize, rice…..) are not toxic remains obscure. The present paper reviews recent contributions from the literature which deal with this subject and addresses, in particular, the question to know how toxicity of cereal prolamins can be modulated through handling by tissue transglutaminase.