INTERLEUKIN-1 AND ITS NATURALLY-OCCURRING ANTAGONIST IN PERITONEAL-DIALYSIS PATIENTS

We have assessed the levels of interleukin-lb (IL-lb) and interleukin- l receptor antagonist (IL-1RA) in both serum and peritoneal dialysate effluents (PDE) from nineteen continuous ambulatory peritoneal dialysi s patients (CAPD) without peritonitis and three CAPD patients with per itonitis. IL-1 beta and IL-1RA were tested using a specific ELISA immu ne-assay. Fifteen normal healthy volunteers served as control. The ser um levels of IL-1RA in CAPD patients were significantly increased comp aratively to their levels in healthy volunteers (p <0.001). CAPD patie nts without peritonitis (stable patients) showed relatively low levels of IL-1RA in peritoneal dialysate effluents (114.4 +/- 85.1 pg/ml). P atients with peritonitis showed very high serum levels of IL-1RA at th e onset of acute infection (4710 +/- 50 pg/ml). The levels of IL-IRA i n PDE were very high during the onset of bacterial peritonitis (5744 /- 254 pg/ml). The clinical recovery from peritonitis was char acteriz ed by a fall in IL-1RA in both serum and dialysate. Serum levels IL-1 beta showed a different pattern, it was not detectable in stable CAPD patients as well as in normal healthy volunteers. It was detectable on ly in serum of patients with peritonitis (10 +/- 0.8 pg/ml). Likewise, in most stable patients, IL-1 beta-PDE levels were not detectable, bu t. substantial amounts can be detected in PDE during bacterial infecti on (80 +/- 15 pg/ml). The increase in serum and PDE levels of IL-1 bet a during bacterial infection was very rapid, this cytokine disappeared in serum and PDE, 2 or 3 days before the clinical recovery. This stud y has demonstrated that CAPD procedure and its complications lead to t he production of small amounts of IL-1 beta but a large amounts of IL- 1RA. The increased production of IL-1RA is a better indicator of the h ost response to CAPD-induced systemic inflammation than IL-1.