Effects of different peritoneal dialysis fluids on the TH1/TH2 balance

Background. Peritoneal dialysis (PD) is associated with a depression of T cell function, as suggested by the impaired production of cytokines by Th cells collected from PD patients. Although treatment biocompatibility could be implicated in this immune dysfunction, it has been poorly investigated, thus far. Therefore, we undertook a study aiming to analyze the effects of different peritoneal dialysis fluids on the Th1/Th2 balance in PD patients. Methods. Twenty three patients on continuous ambulatory peritoneal dialysis (CAPD) were evaluated. Seven patients were on CAPD with icodextrin solution (ICO-PD), seven with glucose and lactate/bicarbonate-buffered solution (LAC/BIC-PD), and nine with glucose and lactate-buffered solution (LAC-PD). The Th1/Th2 balance was evaluated by measuring IFN-gamma (Th1 subset) and IL-4 (Th2 subset), both in circulating and peritoneum-derived Th lymphocytes unstimulated or stimulated by phytohemoagglutinin (PHA). Moreover inflammatory, nutritional and dialysis-related parameters were recorded. Eight normal subjects comprised the control group (CON). Results. Circulating T cells: IFN-gamma was significantly lower in the LAC-PD group (p<0.05) compared to the ICO-PD and LAC/BIC-PD groups. The IFN-gamma/IL-4-producing cell ratio was significantly lower in PD patients than in CON. Peritoneal T cells: after 24-h PHA stimulation, IFN-gamma increased in all patients, but the rise was less pronounced in the LAC-PD group (p<0.05) than in the other two PD groups. The Th1/Th2 ratio was significantly lower in the LAC-PD group when compared both to LAC/BIC-PD and ICO-PD groups. In addition, the LAC-PD group presented a significantly higher rate of peritoneal infections compared to the other PD groups. Conclusions. CAPD with lactate-buffered peritoneal fluid has deleterious effects on the Th1 cell subset, while the use of more biocompatible fluids, bicarbonate-buffered and icodextrin, is associated with a more physiologically representative Th1/Th2 balance and a reduced peritonitis rate.