Celiac disease--how to handle a clinical chameleon.

Celiac disease is an immune-mediated enteropathy triggered by the ingestion of gluten-containing grains (including wheat, rye, and barley) in genetically susceptible persons. The disease is associated with HLA-DQ2 in 90 to 95 percent of cases and with HLA-DQ8 in 5 to 10 percent of cases and is self-perpetuating in the continued presence of gluten. 1 It is the interplay between genes (both HLA and other types) and environment (i.e., gluten) that leads to the intestinal damage that is typical of the disease. 2 Under physiologic circumstances, this interplay is prevented by competent intercellular tight junctions, structures that limit the passage of macromolecules (including gluten peptides) across the intestinal epithelial barrier. Recent evidence suggests that the gluten-induced up-regulation of zonulin, an intestinal peptide involved in the regulation of tight junctions, is responsible, at least in part, for the aberrant increase in gut permeability that is characteristic of the early phase of celiac disease 3