Chapter 74 – Celiac Disease

Celiac disease is an acquired disorder that may be diagnosed at any age, often after a diagnostic delay. The manifestations range from vague signs like anemia, fatigue, and abdominal complaints to severe diarrhea and debilitation. Gliadinreactive T cells can be isolated from the small-intestinal mucosa of celiac disease patients but not from healthy individuals. The gliadin-reactive mucosal T cells are preferentially restricted by the celiac disease–associated HLA-DQ2 and HLA-DQ8 molecules. For the majority of epitopes, the enzyme TG2 is instrumental in making the peptides more immunogenic by converting specific glutamine residues to glutamic acid. Following this deamidation, the peptides fit better in the peptide-binding clefts of DQ2 and DQ8. Therefore, when DQ2- and DQ8-positive individuals encounter dysregulation of TG2 function, possibly influenced by inherent abnormalities of gliadin processing, a pathological immune process might be perpetuated as long as gliadin is present. In its typical form, celiac disease presents in early childhood soon after the infant starts eating gluten-containing food. Constipation is seen surprisingly often in adults.