Influence of dialysis with polyamide vs haemophan haemodialysers on monokines and complement activation during a 4-month long-term study

Background. Contact between blood and dialysis membranes activates mononucl ear cells and the complement system. The extent of activation is dependent on the dialyser material used and is considered an index of biocompatibilit y. Polyamide dialysers consist of a synthetic membrane that, claims high st andards of biocompatibility. Haemophan dialysers represent membranes made o f modified cellulose that are now broadly used for treatment in Europe and are already considered to be more biocompatible than the cuprophane membran es that were used as reference in most previous studies. Methods. In a cross-over treatment study short-term as well as long-term ef fects of a polyamide dialyser with respect to monokine induction and comple ment activation were compared to a haemophan dialyser. Results. Neither haemophan nor polyamide dialysers induced relevant changes in plasma monokine levels. However, in vitro challenge of mononuclear cell s with lipopolysaccharide (LPS) unmasked a significantly stronger preactiva tion for the secretion of proinflammatory monokines during haemophan than p olyamide dialysis. Unlike other monokines the production of the regulatory monokine IL-10 was mainly influenced by individual factors and correlated w ith the patient's immune status rather than the dialyser type used. Enhance d preactivation of monocytes in haemophan compared to polyamide dialysis wa s paralleled by an increased complement activation. Cellular preactivation and formation of terminal complement complex remained constant over the 4-m onth treatment period. Conclusions, Haemophan and polyamide dialysers do not induce changes in pla sma cytokine levels both during short-term and long-term use. However, they significantly differ in complement activation as well as preactivation of monocytes. Preactivated monocytes are prone to secrete high amounts of proi nflammatory cytokines when exposed to a second stimulus like endotoxin. Sec retion of the regulatory cytokine IL-IO is not influenced by the dialyser t ype.