To analyze interleukin (IL)-10, interferon gamma (IFN-y), IL-2, and soluble IL-2 receptor alpha (sIL2Rα) in the dialysate and serum of patients on continuous ambulatory peritoneal dialysis (CAPD).

Samples from dialysate bags were collected during the initial month of dialysis. During peritonitis, samples were collected from the first three bags on the day of admittance to the hospital and from the night bags on days 3 and 10. Serum samples were drawn on days 1 and 10. .Results: IL-10 was detected in all dialysate samples except one on the first day of infection, with a peak median level of 50 pg/mL and a slow decrease thereafter. In serum the median levels never exceeded detectable levels. Patients infected with Escherichia coli or Staphylococcus aureus had higher IL-10 levels in dialysate on day 3 as compared to the remaining patients (p < 0.05). If the catheter had to be drawn, because of persistent cloudy dialysate, the IL-10 levels remained elevated for a longer time (p<0.05). IFN-y and IL-2were detected only in the dialysate of patients infected with either S. aureusor S. epidermidis. Only one serum sample showed increased IFN-y. SIL-2Rα was found in all the serum and dialysis samples from the first day of infection. Contrary to the analyzed cytokines, the receptor showed several fold higher levels in serum as compared to the dialysate. During the infection the receptor levels in the dialysate increased, while they remained stationary in the serum, indicating a local production.

This is the first time IL-10 has been demonstrated in the dialysate during peritonitis in CAPD patients. In view of its role as a suppressor of the immune and inflammatory responses, it is a potentially important observation, which might have clinical implications in the future.