NON-ENDOTOXINIC TUMOR NECROSIS FACTOR-ALPHA-INDUCING FACTORS IN HEMODIALYSIS

A transmembrane passage of endotoxins may account for the dysfunction of cytokine production which has been often reported in haemodialysis. We developed an assay based on the ability of patient serum to stimul ate tumour necrosis factor alpha (TNF alpha) secretion in normal perip heral blood mononuclear cells. Three groups of subjects were investiga ted: normal controls (n = 14), patients with chronic renal failure, CR F (n = 15), and patients dialysed with polyacrylonitrile (n = 7), poly sulphone (n = 8), and cellulose acetate (n = 7). Sera from dialysed pa tients displayed a significantly higher TNF alpha-inducing activity th an those of controls and CRF patients. The ability of serum to elicit TNF alpha secretion was neither modified during the dialysis session n or influenced by the type of haemodialysis membrane. TNF alpha-inducin g activity in serum was not inhibited by polymyxin B, known to impair endotoxin-dependent cell responses, thus suggesting that it was not re lated to circulating endotoxins. We conclude that non-endotoxinic fact ors are present in serum from dialysed patients and are able to induce cytokine secretion.