A total of 105 patients participated in this study, including 10 with chronic glomerulonephritis with normal renal function (CGN patients), 36 uraemic patients (CRF patients), 19 continuous ambulatory peritoneal dialysis patients (CAPD) without peritonitis, three CAPD patients with peritonitis, 37 patients undergoing chronic haemodialysis (HD) divided into short-term HD, 15 patients; medium-term HD, 12 patients; and long-term HD, 10 patients. IL-8 and two other proinflammatory cytokines, IL-6 and TNF alpha were tested using a specific immunoassay. IL-8, IL-6, and TNF alpha serum levels were significantly increased in patients with chronic renal failure compared to their levels in normal individuals (P < 0.0001, P < 0.05 and P < 0.0001 respectively). The most pronounced increment in IL-8, IL-6 and TNF alpha serum levels was observed in CAPD patients (P < 0.0001). CAPD patients without peritonitis showed relatively low levels of IL-8 or IL-6 in peritoneal dialysate effluents (PDE), whereas PDE-TNF alpha were not detectable in almost all patients tested. Patients with peritonitis showed very high serum and PDE levels of IL-8, IL-6 and TNF alpha. The clinical recovery from peritonitis was characterized by a rapid fall in IL-8, IL-6 and TNF alpha in serum and dialysate. HD patients showed a significant increase in serum levels of IL-8 and also IL-6 and TNF alpha compared to normal individuals (P < 0.05, P < 0.05 and P < 0.01 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)