Context :Obstructive pancreatitis is a specific form of pancreatitis, which is caused by the obstruction of the main pancreatic duct due to tumors or some other causes. Interleukin-8 is induced in acute pancreatitis, but its expression in obstructive pancreatitis has not been clarified. Objective :We attempted to provide some insight into the significance of interleukin -8 in the pathogenesis of pancreatic fibrosis. Patients :Fifteen cases of pancreatic cancer, 7 cases of mucinous cystadenoma, 3 cases of Vater’s papilla cancer and 9 normal pancreases were included in this study. Main outcome measures :The obstructive pancreatitis portions of the above pathologies were evaluated for interleukin-8 expression by means of immunohistochemistry and in situ hybridization. Results :Interleukin-8 was positive in 72% of cases of obstructive pancreatitis. The positive rate was not significantly related to the etiology of the obstruction (P=0.972). Interleukin-8 was expressed in infiltrating cells, proliferating ductular cells and acinar cells. In contrast, normal pancreases and tumor cells lacked interleukin-8 expression (P<0.001 vs. obstructive pancreatitis). Both immunohistochemistry and in situ hybridization demonstrated that interleukin-8 was expressed mostly in acinar cells in mild pancreatic fibrosis, whereas it was expressed in stromal and ductular cells in moderate and severe pancreatic fibrosis. Conclusions These results suggest that interleukin-8 expression is related to the fibrotic process in obstructive pancreatitis.
Yoshiharu Motoo, Min-Jue Xie, Hisatsugu Mouri, Norio Sawabu