Peritoneal Defence Mechanisms and Staphylococcus Aureus in Patients Treated with Continuous Ambulatory Peritoneal Dialysis (CAPD)

Peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients due to S. aureus is associated with an adverse clinical outcome, suggesting impaired clearance of this organism by the host. The ability of peritoneal macrophages (PMO) derived from CAPD patients to take up S. aureus and mount a respiratory burst was investigated. Whilst significant activity was observed in the absence of opsonin, both parameters of phagocytosis were augmented by addition of 20 % pooled human serum (PHS), complement-depleted PHS, and fibronectin. When used as sole opsonin, fibronectin resulted in a dose-related increase in chemiluminescent response by both blood neutrophils and PMO. The opsonic activity of dialysis effluent, as judged by neutrophil chemiluminescence, correlated with IgG and fibronectin content, but not with complement as as sessed by C3 levels. The addition of urokinase to dialysate improved its opsoni