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 study Il-8 du ring peritoneal inflammation. Eleven episodes were studied in nine pat ients, who were followed on 8 consecutive days from the start of perit onitis and once after recovery (control). Il-8 was measured in dialysa te (night dwells) and serum. The Il-8 time course was compared to Il-6 and TNFalpha. In addition, an in-vivo relationship between dialysate Il-8 and intraperitoneal accumulation of neutrophils was studied. A hi ghly increased peritoneal appearance rate of Il-8 was found in the acu te phase that decreased to control values during recovery. A remarkabl e parallelism was observed for dialysate 11-8 and Il-6 with respect to the time course and the peritoneal appearance rate. In contrast, the appearance rate of TNFalpha was much less and had a different time cou rse. In three of four cases where the dialysate Il-8 peak occurred on day 2, the dialysate Il-6 peak still coincided with 11-8, in contrast to TNFalpha (always day 1). Dialysate Il-8 generally exceeded serum co ncentrations during the entire follow-up, indicating intraperitoneal I l-8 synthesis. A positive correlation was present between the dialysat e 11-8 peak and the maximal number of neutrophils in dialysate. This r elationship was absent for Il-6 and TNFalpha. In five of six episodes where neutrophils were quantified on both day 1 and 2, the Il-8 peak o ccurred simultaneously with the neutrophil peak. These findings sugges t that Il-8 is involved in the recruitment of neutrophils towards the dialysate during peritonitis.