DIALYSATE CELL-POPULATION AND CANCER-ANTIGEN-125 IN STABLE CONTINUOUSAMBULATORY PERITONEAL-DIALYSIS PATIENTS - THEIR RELATIONSHIP WITH TRANSPORT PARAMETERS

We investigated the total cell count and cell population of the overni ght peritoneal dialysis effluent (PDE) by flow cytometry in 76 stable continuous ambulatory peritoneal dialysis (CAPD) patients. The mean pe rcentage of mesothelial cells and macrophages was 4.4% and 57%, respec tively. A higher percentage of dead cells among the mesothelial cells compared with other cell populations in the PDE was observed. Peritone al transport properties were studied in every patient by determining t he dialysate to plasma ratio of creatinine concentration (D/P) at the fourth hour of the peritoneal equilibration test, and the mass transfe r area coefficient of creatinine (MTACCr) or glucose. Cancer antigen 1 25 (CA125), suggested as a bulk marker for the mesothelial mass in sta ble peritoneal dialysis patients, was determined in the PDE. No correl ation was demonstrated between CA125 and the number of mesothelial cel ls, lymphocytes, or macrophages in the PDE. A significant correlation was observed between CA125 and different parameters of peritoneal tran sport (D/P and MTACCr). On the contrary, neither the history of perito nitis nor the duration of CAPD appeared to affect the CA125 concentrat ion in the PDE. The tack of correlation between CA125 in the PDE and t he duration of CAPD may be related to the early loss of peritoneal tra nsport properties as a result of the use of hypertonic dialysate in th e majority of our patients with small-volume CAPD (3 x 2 L daily excha nge). Our findings suggest that CA125 may not necessarily correlate we ll with the number of mesothelial cells in PDE. In patients with vanis hing of the mesothelial layer, the measurement of CA125 (as a bulk mar ker for the mesothelial mass in the peritoneum) may reflect the change of peritoneal transport properties. (C) 1997 by the National Kidney F oundation, Inc.