Response of peripheral blood mononuclear cells in hemodialyzed patients against endotoxin and muramyldipeptide.

Microbial fragments of endotoxin (ET) and peptidoglycan (PG) are recognized as pyrogen in dialysate. The aim of this study was to evaluate the effect of contaminated dialysate on peripheral blood mononuclear cells (PBMC) in hemodialyzed patients by measuring production of interleukine 1-beta (IL-1beta) in vitro. Venous blood was withdrawn before dialysis session. The effects of a dialysis membrane, a magnitude of dialysate contamination and a duration of hemodialysis were studied. PBMC was stimulated by the addition of water containing either ET or muramyldipeptide (MDP), the minimum biological activated fragment of PG, or ET+MDP. IL-1beta production of PBMC stimulated by ET or ET+MDP in patients on hemodialysis using a polysulfon (PS) membrane was significantly lower than those using a cuprammonium-rayon (CU) membrane, ethylenevinylalcohol (EVAL) membrane, polymethylmetacrylate (PMMA) membrane, respectively. Among patients on the PS membranes, those who were exposed to dialysate with higher pyrogen contamination had lower PBMC cytokine production than those dialyzed with ultrapure dialysate. Response of PBMC in patients against ET+MDP stimulant decreased with duration of dialysis treatment. This suggested that chronic exposure to ET or MDP during hemodialysis treatment, might cause a tolerance against ET and ET+MDP in PBMC.