Citokine release in patients on haemodiafiltration on-line

Pyrogenic substances [Endo-exotoxins (ET)] derive from contaminated dialysa te. Every dialyzer membrane is permeable to endotoxin. ET may cross dialyze r membranes either by backfiltration or diffusion. ET induce cytokine produ ction in blood mononuclear cells. Chronic cytokine release can induce an in flammatory state in hemodialysis patients, related to morbidity and mortali ty of these patients. Hemodiafiltration on-line (HDF-OL) is a high efficien cy technique of dialysis. The safety of on line production of substitution fluid by a two-stage ultrafiltration is evaluated in this study. Also we co mpared blood levels of cytokines and ET in patients on hemodialysis switche d to HDF-OL. Five patients stable on bicarbonate high-flux hemodialysis (HD) were switch ed to HDF-OL, with 110 ml/min of postdilutional infusion. High-flux polysul fone, HF80 Fresenius Polysulfone(R), were used in both technique. Plasma TN F-alpha, IL-6, slL-2r alpha and endotoxins, LAL assay, were measured when p atients were on HD and at first, fourth and 12(th) weeks on HDF-OL. Microbi ological counts and levels of endotoxins (Chromogenic LAL assay) were perfo rmed in dialysate after each two-stage ultrafiltration (Diasafe(R) y Filtro -OL(R)). No pyrogenic reactions were observed during the study period. Mean endotoxi n level in dialysate before dialyzer at the beginning of dialysis was 0.32 +/- 0.26 UE/ml, n = 20 and 0.11 +/- 0.06 UE/ml at the end of session. The i nfusion fluid after OL-Filter(R) was sterile and contained no detectable ET . Plasma endotoxin levels decreased in the HDF-OL periods respect to the fi rst one, in no. Plasma TNF alpha concentrations did not significantly chang e during the study. Plasma IL-6 levels increased significantly in the last period on HDF-OL with respecto to HD control, p < 0.01. Plasma sIL-2r level s decreased, p < 0.01, in HDF-OL periods respect to HD control. The ratio p ostdialysis/predialysis concentrations of TNF alpha, IL-6 and slL-2r remain ed between 0.78 and 1.2, without significant changes. Microbiological count s, CFU/ml in dialysate did not correlate with ET levels either measured in plasma or in dialysate; however dialysate ET levels were significantly high er in hemodialysis where microbiological counts were elevated, p < 0.05. Cy tokine levels did not correlate with ET levels, only slL-2r level correlate d significantly with dialysate ET concentration, at the beginning of dialys is. In conclusion HDF-OL is confirmed to be a safe procedure compared to high-f lux HD with respect to microbiological and endotoxins control.