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

Background A major drawback of continuous ambulatory peritoneal dialys is (CAPD) is the occurrence of peritoneal infection. This might be exp lained 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 def ence against Staphylococcus aureus in an experimental dialysis model i n rats. Methods. Twenty-four hours after the administration of either dialysis fluid containing various glucose concentrations or saline wit h or without IFN, bacteria were injected intraperitoneally. At the tim e of the bacterial infection and 24 h later cellular and bacterial par ameters were studied. Results. The addition of IFN to dialysis fluid o r 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 signifi cantly (P<0.01) reduced the recovery of bacteria from the peritoneal c avity 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 cavit y by means of activation of an increased number of macrophages.