Cytokine mRNA levels and lymphocyte infiltration in pancreatic tissue during experimental chronic pancreatitis induced by dibutyltin dichloride

There is little information available regarding the role of inflammatory ce lls in the pathogenesis of chronic pancreatitis. Therefore, we analyzed the local cytokine profile and infiltrating lymphocytes in a rat model of chro nic pancreatitis. Experimental pancreatitis was induced by a single intrave nous application of dibultyltin dichloride (DBTC). During a time course of two months we observed the mRNA expression of cytokines using competitive R T-PCR. Lymphocytes were characterized by immunohistochemistry, FACS analysi s, and the lymphocyte proliferation test. IL-1 beta, IL-6, IL-5, and IL-10 were immediately up-regulated in the acute phase of disease, while lymphocy te-restricted expression of IL-2, IL-2R, and IFN-gamma was only found in th e chronic course. Among the infiltrating lymphocytes, CD4(+) cells dominate d, but during the chronic process there was an increase of CD8(+) cells, re sulting in a reduced CD4/CD8 ratio. Mitogen-induced activation of isolated mesenteric lymph node cells increased during the chronic inflammation. Our results suggest that in experimental pancreatitis acute inflammatory reacti ons are followed by a T-lymphocyte-mediated process.