Comparison of Peritoneal White Blood Cell Parameters From Continuous Ambulatory Peritoneal Dialysis Patients With a High or Low Incidence of Peritonitis

The purpose of this study was to determine if there were differences in selected dialysate white blood cells (WBC) parameters between continuous ambulatory peritoneal dialysis (CAPD) patient groups identified as having a high or low incidence of peritonitis. Parameters studied were total peritoneal WBC yield, percentage and absolute number of various WBC types, and expression of WBC receptors known to be involved in normal host defense mechanisms. WBCs were obtained from peritoneal dialysis effluents (overnight dwell), which were collected at monthly intervals for 6 to 8 months from eight CAPD patients-four with a history of high peritonitis incidence (HPI) (more than two episodes in 12 months) and four with a history of low peritonitis incidence (LPI) (no episodes in more than 24 months). Our results demonstrated that there was no significant difference in the overall mean total cell yields or absolute cell counts between the two patient groups. WBC differentials, although differing somewhat among patients, stayed quite stable over time for an individual patient and there was no significant difference between the two patient groups. Analysis of receptors on the peritoneal WBC was performed using flow cytometry and fluorescein-conjugated chemotactic factors (C5a and Met-Leu-Phe-Lys), as well as monoclonal antibodies specific for Fc receptors and complement receptors, CR1(CD35) and CR3 (CD11 b). Although there was a trend toward increased expression of all of these receptors in the HPI patients, there was no significant difference in the fluorescence intensity of peritoneal neutrophils or macrophages that expressed these receptors between the two patient groups. It has been proposed that altered peritoneal host defense mechanisms exist in patients with a high rate of peritonitis. However, based on the parameters analyzed in this study, no significant differences could be found among patients or between groups identified as having a high or low incidence of peritonitis.