<human>:  What is the disease called ‘celiac disease’?
<bot>: Celiac disease is an autoimmune disorder. It is triggered by a dietary gluten. Gluten is a protein found in wheat, rye, and barley. When someone has celiac disease, their immune system mistakenly attacks the lining of the small intestine. This causes damage to the villi, which are the tiny fingerlike projections that line the small intestine. This damage makes it difficult for the body to absorb nutrients.