DIFFERENCE IN THE BLOOD MONOCYTE PHENOTYPE BETWEEN UREMIC PATIENTS AND HEALTHY CONTROLS - ITS RELATION TO MONOCYTE DIFFERENTIATION INTO MACROPHAGES IN THE PERITONEAL-CAVITY

The phenotypic alterations between blood monocytes from 11 patients wi th end-stage renal disease, who had been on peritoneal dialysis for le ss than one week, and blood monocytes from 10 healthy controls, were a nalyzed. In addition, peritoneal macrophages in the dialysate effluent were enclosed. Analysis of functional receptor density was performed using immunostaining and flow cytometry. The phenotypic characterizati on was selected to represent various biological functions such as adhe sion, phagocytosis (CD11b/CD18, CD11c/CD18, CD16), antigen-presentatio n (HLA-DR, ICAM-1), differentiation (transferrin receptor, CD71), rece ptor for LPS (CD14) and initiation of the coagulation cascade (Tissue factor, CD142). The proportion of CD16-positive blood monocytes and th e quantitative level of ICAM-1 were higher in the patient group, compa red to healthy controls. A significant increase in the quantitative le vel of CD11b/CD18, CD11c/CD18, HLA-DR and ICAM-1, transferrin receptor , CD14 and CD16, was found on peritoneal macrophages, compared to mono cytes, harvested both from the corresponding patients, as well as from healthy donors. In contrast, we did not find any significant differen ces in the expression of tissue factor between monocytes and peritonea l macrophages. In conclusion, phenotypic differences exist between mon ocyte populations in the blood circulation of CAPD patients, and healt hy individuals. We also show that transmigration of monocytes into the peritoneal cavity implies a selective up-regulation of functional rec eptors, preferentially related to adhesion, and antigen-presentation i n a steady-state situation in non-infected CAPD patients.