EFFECT OF INTERFERON-GAMMA IN DIALYSIS FLUID ON PERITONEAL DEFENSE IN RATS

Background A major drawback of continuous ambulatory peritoneal dialysis (CAPD) is the occurrence of peritoneal infection. This might be explained by a non-optimal phagocytic capacity of peritoneal cells which can be improved by stimulating factors. Aim. To investigate the effect of addition of interferon-gamma (IFN) to dialysis fluid with various glucose concentrations or to saline (as control) on the peritoneal defence against Staphylococcus aureus in an experimental dialysis model in rats. Methods. Twenty-four hours after the administration of either dialysis fluid containing various glucose concentrations or saline with or without IFN, bacteria were injected intraperitoneally. At the time of the bacterial infection and 24 h later cellular and bacterial parameters were studied. Results. The addition of IFN to dialysis fluid or saline resulted in a significant (P<0.01) increase in the number of peritoneal macrophages at the time of infection; this was accompanied by a significant increase in both the number of Ia-positive peritoneal macrophages (P<0.01) and the production of nitrite by macrophages (P<0.05) at that time. IFN in dialysis fluid as well as in saline significantly (P<0.01) reduced the recovery of bacteria from the peritoneal cavity 24 h after infection. Only the absence of IFN glucose increased the recovery of bacteria from the peritoneal cavity at the same time. Conclusion. In this experimental model the addition of IFN to dialysis fluid lowered the recovery of staphylococci from the peritoneal cavity by means of activation of an increased number of macrophages.