Expression of interleukin-8 in human obstructive pancreatitis.

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.