© American Society for Clinical Pathology Anatomic Pathology / ENTEROCYTE JUNCTIONS IN CELIAC DISEASE Altered Expression, Localization, and Phosphorylation of Epithelial Junctional Proteins in Celiac Disease

We aimed to study the expression and localization of the molecular components of enterocyte junctions in celiac disease together with the level of tyrosine phosphorylation, a phenomenon known to affect their cellular distribution and function, and to explore the influence of proinflammatory cytokines. Duodenal biopsy specimens from patients with celiac disease and control subjects were used for immunoprecipitation, immunoblotting, and immunolocalization by using antioccludin, anti–zonula occludens (ZO)-1, anti– E-cadherin, anti–β-catenin, and antiphosphotyrosine antibodies. The same procedures were carried out on filter-grown Caco-2 cells incubated in the absence or presence of interferon γ and tumor necrosis factor α. In active celiac disease, the absence of a phosphorylate