Variations of cytokine levels and production in CAPD patients

Macrophages, predominant cells in dialysates of patients on CAPD without peritonitis, produce a wide variety of substances including cytokines. The aim of this study was to examine the cytokine production in five uninfected patients. This work investigated the presence in dialysates of interleukin-1beta, interleukin-6, interleukin-8, tumor necrosis factor alpha and the ability of peritoneal macrophages to produce these cytokines. These results were compared with values obtained from control group in non-uremic conditions (peritoneal lavage with isotonic saline or dialysis fluid). All cytokines were detectable in dialysates. Interindividual variations in cytokine concentration in dialysates were wider than variations of production of cytokines ex vivo by stimulated and unstimulated cells. In control group, dialysis fluid inhibited the cytokine production and with isotonic saline, cells produced less cytokines than dialysis patients' cells. The highest levels of interleukin-1 and tumor necrosis factor in dialysates and the highest capacity to respond to LPS were observed in patients having the shortest duration of dialysis. The variability observed did not seem to be due to cells themselves but to their environment.