Increased expression of CD25 and HLA-DR on lymphocytes recruited into the peritoneal cavity in non-infected CAPD patients.

The impact of uremia per se, peritoneal dialysis (PD) and hemodialysis (HD) treatment was evaluated on characteristics of lymphocytes. CD4, CD8, CD25 and HLA-DR were analyzed, with flow cytometry, in lymphocytes prepared from peripheral blood of uremic (n = 10) and hemodialysis patients (n = 10). Peritoneal dialysate was also obtained from patients on CAPD (n = 12). A decreased relative and absolute lymphocyte count was observed in peripheral blood from uremic, HD and CAPD patients compared to healthy controls (p < 0.03, p < 0.03 and p < 0.02, respectively). On the other hand, the relative distribution of lymphocytes was significantly higher in peritoneal dialysate compared to peripheral blood of CAPD patients (p < 0.02). Likewise, the absolute CD4 positive lymphocyte count was lower in the peripheral blood from uremic. HD and CAPD patients as compared to healthy controls (p < 0.001, respectively). In CAPD patients the relative distribution of CD4 positive cells (p < 0.001) was lower, while quantitative CD25 level (p < 0.01) and the relative count of HLA-DR (p < 0.0001) was increased in the peritoneal dialysate compared to blood. Taken together a selective activation of lymphocytes in peritoneal dialysate as compared to peripheral blood from uremic, HD and CAPD patients was observed. The altered biological function of the inflammatory cells may therefore explain the increased susceptibility to infectious diseases.