Hemodialysis-associated induction of cytokines

A number of studies demonstrated an induction of cytokines during hemodialysis; possible mechanisms are complement factors activated on the membrane and bacterial products from the dialysate. When comparing the permeability of different membranes regarding bacterial products, several issues have to be perceived: the limulus-test is not sufficient for detection of bacterial products, cytokine induction is a better parameter. Synthetic membranes adsorb bacterial products. The plasma protein layer on the membrane prevents penetration of bacterial products from the dialysate. When using complement-activating membranes, there is a synergism between complement and bacterial products on cytokine induction. In vivo studies demonstrated that pyrogen-free, ultrafiltered dialysate as well as the use of "biocompatible" membranes reduce cytokine induction and the inflammatory reaction in dialysis patients. The long-term clinical consequences of pyrogen-free dialysate and "biocompatible" membranes are not proven yet; a repetitive induction of cytokines may have detrimental effects on beta(2)-amyloidosis and cardiovascular complications in dialysis patients.