Cytokine production by monocytes during haemodialysis.

In order to follow the effect of haemodialysis on monocyte function, we measured the release of interleukin-1 beta (Il-1), interleukin-6 (Il-6), and tumour necrosis factor alpha (TNF alpha) from cultured monocytes isolated before and after dialysis. Monocytes obtained from patients before dialysis released smaller amounts of cytokines than cells from healthy controls. The choice of the dialysis membrane had no effect on predialytic monocyte activity. Basal cytokine release after dialysis remained virtually unchanged, irrespective of the membrane material used. When stimulated with LPS, cells significantly produced more cytokines than under basal conditions. Stimulated monocytes isolated before dialysis produced considerably more cytokines than cells obtained at the end of the dialysis. Taken together, uraemia by itself seemed to depress monocyte activity. Haemodialysis either with cuprophan or PMMA dialysers had no influence on basal cytokine release during a 24-h period following dialysis. Uraemic monocytes, however, appeared to be primed, since stimulation with LPS in vitro caused a more pronounced release of cytokines than in healthy volunteers.