Interleukin-8 during peritonitis in patients treated with CAPD; an in-vivo model of acute inflammation

CAPD-related peritonitis was used as an in-vivo model to studyI1-8 during peritoneal inflammation. Eleven episodes were studiedin nine patients, who were followed on 8 consecutive days fromthe start of peritonitis and once after recovery (control).I1-8 was measured in dialysate (night dwells) and serum. TheI1-8 time course was compared to I1-6 and TNF. In addition,an in-vivo relationship between dialysate I1-8 and intraperitonealaccumulation of neutrophils was studied. A highly increased peritoneal appearance rate of I1-8 was foundin the acute phase that decreased to control values during recovery.A remarkable parallelism was observed for dialysate I1-8 andI1-6 with respect to the time course and the peritoneal appearancerate. In contrast, the appearance rate of TNF was much lessand had a different time course. In three of four cases wherethe dialysate I1-8 peak occurred on day 2, the dialysate I1-6peak still coincided with I1-8, in contrast to TNF (always day1). Dialysate I1-8 generally exceeded serum concentrations duringthe entire follow-up, indicating intraperitoneal I1-8 synthesis.A positive correlation was present between the dialysate I1-8peak and the maximal number of neutrophils in dialysate. Thisrelationship was absent for I1-6 and TNF. In five of six episodeswhere neutrophils were quantified on both day 1 and 2, the I1-8peak occurred simultaneously with the neutrophil peak. Thesefindings suggest that I1-8 is involved in the recruitment ofneutrophils towards the dialysate during peritonitis.