Enhanced intestinal expression of heat shock protein 70 in patients with inflammatory bowel diseases

Heat shock protein (Hsp) 70 is stress-inducible and exhibits both protective and antigenic properties. This study investigated the mucosal expression of the constitutive (Hsp70c) and inducible form (Hsp70i) as well as antibodies against human Hsp70 in inflammatory bowel disease and controls. Biopsies were assessed by immunoblot and immunofluorescence, resection specimens by immunohistochemistry, and mucosal antibody content by isoelectric focusing. Compared to controls, expression of Hsp70 was enhanced in ulcerative colitis (P<0.05), less so in Crohn's disease and infectious colitis. Strong epithelial staining was found for Hsp70c and Hsp70i in both diseases. Mucosal and submucosal mononuclear cells showed enhanced Hsp70c expression in Crohn's disease and to a lesser degree in ulcerative colitis. Antibodies of isotypes A or M were detected in nearly all patients and controls. The different pattern of Hsp70 expression in Crohn's disease compared to ulcerative colitis points to a distinct protective and immunological function, whereas a role in autoimmunity seems unlikely.