INTERLEUKIN-8 PRODUCTION BY HUMAN PERITONEAL MESOTHELIAL CELLS IN RESPONSE TO TUMOR-NECROSIS-FACTOR-ALPHA, INTERLEUKIN-1, AND MEDIUM CONDITIONED BY MACROPHAGES COCULTURED WITH STAPHYLOCOCCUS-EPIDERMIDIS

Patients treated with continuous ambulatory peritoneal dialysis (CAPD) may suffer from recurrent peritonitis episodes caused by StaPhylococc us epidermidis. Early recruitment of granulocytes from the peripheral blood is important for the peritoneal antibacterial defense of CAPD pa tients. In this study, human peritoneal mesothelial cells were shown t o produce high levels of interleukin-8 (IL-8) in response to IL-1beta and tumor necrosis factor-alpha (TNFalpha) but not lipopolysaccharide or S. epidermidis. Coculture of peritoneal macrophages with S. epiderm idis induced high levels of IL-1alpha, IL-Ibeta, and TNFalpha in 24-h- conditioned medium. Preincubation of this medium with anti-TNFalpha, a nti-IL-1alpha, or anti-IL-1beta partially blocked stimulation of IL-8 production by mesothelial cells. Added together, these antibodies abol ished IL-8 production to a level just above background. Migration of g ranulocytes to the stimulated mesothelial cell-conditioned medium coul d be totally blocked with rabbit polyclonal anti-IL-8 antibody. Thus, mesothelial cells are important for the recruitment of granulocytes in to the peritoneal cavity.