PERITONEAL INTERLEUKIN-8 IN ACUTE APPENDICITIS

Interleukin-8 (IL-8) is a chemoattractant that is highly selective for neutrophils, This study was designed to investigate the presence of I L-8 in peritoneal fluid of patients with acute appendicitis, The clini cal circumstances underlying the secretion of IL-8 by mesothelium and its mechanism of activation have not been defined, In an in vitro mode l for bacterial peritonitis the role of bacteria in activating human m esothelial cells to secrete IL-8 was studied, Cultured human mesotheli um was incubated with various species of pathogenic bacteria, isolated from peritoneal exudate fluids of patients with appendicitis, The amo unt of IL-8 secreted by the cultured mesothelial cells was determined in an IL-8 ELISA, as IL-8 was present in the original peritoneal fluid of these patients, Peritoneal fluids from patients with a perforated appendix were found to contain a significantly higher concentration of IL-8 compared to peritoneal fluids from patients with nonperforating appendicitis (121.6 (57.8) ng/ml versus 0.2 (0.07) ng/ml, respectively ; mean (SEM), P less than or equal to 0.01), Species of Bacteroides an d Fusobacterium necrophorum induced IL-8 secretion from cultured mesot helial monolayers to levels comparable to those found in peritoneal fl uids in vivo, Heat-killed bacteria and bacterial supernatant were also able to stimulate mesothelium to secrete IL-8, The results suggest th at in the early phase of bacterial peritonitis the influx of PMN is re gulated by bacteria-induced IL-8 secretion by the mesothelium lining t he peritoneal cavity. (C) 1996 Academic Press, Inc.