LONG-TERM CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS REDUCES THE EXPRESSION OF CD11B, CD14, CD16, AND CD64 ON PERITONEAL-MACROPHAGES

Objective: To characterize phenotypically the macrophages from nocturn al peritoneal effluent (NPE) in patients on continuous ambulatory peri toneal dialysis (CAPD), and to determine the influence of the length o f this therapy on macrophage (M Phi) function. Design: Cross-sectional descriptive study. Patients: Fifty-five patients on CAPD who were cla ssified into short-, medium-, and long-term groups according to their time on CAPD. Peritoneal macrophages (PM Phi) were also characterized in 7 patients at the time of catheter placement, and there were 13 nor mal controls. Interventions: Macrophages were collected from NPE by ce ntrifugation. Measurements: Membrane receptor expression was evaluated by flow cytometry analysis. Results: Flow cytometry analysis revealed that the expression of CD11b, CD16, CD64, and CD14 on NPE macrophages was reduced during the course of CAPD treatment, reaching levels whic h represented a 40%-50% reduction of the cell surface expression detec ted at the start of the treatment or on normal control macrophages. Bo th normal and CAPD PM Phi expressed CD4, CD69, and CD71 very weakly an d lacked CD25. No changes in HLA-DR or in other adhesion protein (CD11 a, CD11c, CD18, CD54) expression were detected, and levels were simila r in both patients and normal controls. Conclusion: Our results show t hat long-term CAPD might affect Fc gamma receptor-mediated phagocytosi s by reducing the expression of CD16, CD64, and CD11b. Lower CD11b and CD14 expression would also impair PM Phi adhesion to mesothelial stru ctures.