Short dwell times reduce the local defence mechanism of chronic peritoneal dialysis patients.

The effect of different intraperitoneal dwell times on the phagocytic capacity of the effluent-derived macrophages in 6 peritoneal dialysis patients was studied. The number of peritoneal cells increased after longer dwell times, and a significant increase in the percentage of macrophages phagocytosing opsonized sheep red blood cells [( IgG]SRBC) and unopsonized latex beads was determined when the dwell time increased from 1.5 to 15 h. Thus, the total phagocytic capacity of the effluent-derived macrophages dramatically increased with prolonged dwell times. In addition, the IgG concentration showed a five-fold increase following long intraperitoneal dwell times. The increasing IgG levels were accompanied by an increase, however not significant (p less than 0.06), in the opsonic activity of the effluents. The increase in local phagocytic and opsonic capacity following longer intraperitoneal dwell times must be taken in consideration by dialysis fluid exchange schedules of peritoneal dialysis patients.