Celiac sprue is a disorder of the immune system whereby the normal lining of the small bowel is damaged by an allergic type of reaction from a protein in wheat, barley and rye called gluten. The normal frond-like tiny tubular projections within the jejunum, called villi, are badly damaged. It is through these villi that nutrients move into the blood stream. When these are damaged by the gluten immune reaction, nutrients no longer are absorbed properly. Malnutrition occurs. Compared to the previous normal lining with its numerous pinpoint projections of light, you see that this lining is smooth and reddened or inflamed. This is a very abnormal appearance.