Heat shock protein expression is low in intestinal mucosa in juvenile idiopathic arthritis: a defect in immunoregulation?

Methods: We studied 15 patients with JIA. Controls included 13 children without JIA, studied for various gastrointestinal (GI) symptoms, but eventually shown not to have any GI disease. The subjects were examined by endoscopy. The expression of HSP60, HSP70, MICA, and HSF1 was analysed in ileal and duodenal biopsies by using immunohistochemistry. Results: The expression levels of HSP60, MICA, and HSF1 were significantly lower in the duodenal epithelium in the JIA patients compared to the controls. MICA and HSF1 also showed lower expression in the ileal epithelium. The expression of HSP70 did not differ between the groups. Conclusions: The downregulation of HSP60, MICA, and HSF1 in small intestinal mucosa may indicate that intestinal epithelial cells show immune aberration in JIA. We speculate that the low heat shock response may play a role in the pathogenesis of JIA, interfering with mucosal integrity and local intestinal immunoregulation.