THE EFFECT OF ULTRAFILTERED DIALYSATE ON THE CELLULAR CONTENT OF INTERLEUKIN-1 RECEPTOR ANTAGONIST IN PATIENTS ON CHRONIC-HEMODIALYSIS

We investigated the effect of dialysate ultrafiltration on the content of IL-1 receptor antagonist (IL-1Ra) in mononuclear cells (PBMC) as a marker of the inflammatory response. 11 patients on Cuprophan dialyzers were randomly assigned to treatment with standard bicarbonate dialysate first and then to ultrafiltered dialysate or the reverse order in a crossover design. In each treatment period (at least 4 weeks) weekly separations of PBMC were performed before the start of dialysis. Cellular content of IL-1Ra was determined in PBMC that were frozen immediately after separation; all values of IL-1Ra in each treatment period were averaged. The dialysate contained a median of 148 (range, 61-400) colony-forming units without dialysate filter; no bacterial growth was detected in ultrafiltered dialysate. The median endotoxin content was 80 pg/ml in nonfiltered dialysate; endotoxin was below 5 pg/ml in ah ultrafiltered dialysate samples. Cellular content of IL-1Ra decreased in all but 1 patient with the use of ultrafiltered dialysate (mean+/-SEM: 1,467+/-113 pg/ml without dialysate filter vs. 1,166+/-104 pg/ml with filter, p = 0.016). The present study demonstrates that the bacterial contamination of the dialysate induces a systemic inflammatory response in hemodialysis patients.