Influence of PMN leukocyte-mediated pancreatic damage on the systemic immune response in severe acute pancreatitis in rats.

The outcome of severe acute pancreatitis is determined by the development of the systemic inflammatory response and subsequent multiorgan dysfunction. Using the taurocholate-induced model of acute pancreatitis in rats, we investigated the relationship between early polymorphonuclear (PMN)-mediated pancreatic tissue damage and the systemic inflammatory response. The respiratory burst of PMN leukocytes was increased in animals with acute pancreatitis and was reduced by anti-ICAM-1 antibody and oxygen radical scavenger treatment after 24 hr. In acute pancreatitis a reduced number of peripheral helper T cells was evident, most likely due to L-selectin-mediated increased lymphocyte homing. After 24 hr the CD45RC(high)/CD45RC(low) ratio of helper T cells, a critical factor in T cell-mediated disease was increased due to a reduction of regulatory CD45RC(low) cells. Only the treatment with anti-ICAM-1 mAb affected these changes, indicating that immunological changes in necrotizing pancreatitis are only in part affected by early PMN leukocyte-mediated pancreatic damage.