The peritoneal immune system and continuous ambulatory peritoneal dialysis.

Continuous ambulatory peritoneal dialysis (CAPD) has been an established treatment for end-stage renal disease for about 20 years. A major problem of CAPD is the relatively high incidence of peritonitis, and this fact has served as a stimulus to nephrologists to study the immune mechanisms of the peritoneum. It is by now well established that all three main cell systems present in the peritoneal cavity, namely, macrophages, lymphocytes and mesothelium, are involved in the initial peritoneal immune response, resulting in a massive recruitment of leucocytes from the peripheral blood, via the mesothelial cell layer, into the peritoneal cavity. However, this mechanism is adversely affected by the presence of commercial dialysis solution (CDS), which is highly unphysiological, in the peritoneal cavity. These processes are the subject of this review.