Chronic renal failure induces a clinical state of immunodefi ciency that also depends upon a wide spectrum of dialysis membranes used during hemodialysis. Previous studies have shown that cellular immunodeficiency is caused by malfunc tion of the antigen presenting cells (monocytes or granulocytes). Subsequent activation of rolling mononuclear leuko cytes results in up-regulated expression of CD11b/CD18 (Mac-1) on endothelial cells. It is postulated that a VitE coated dialysis membrane might minimize the membrane biocompatibility, thereby generating a smaller amount of re active oxygen species (ROS). The purpose of this study was to evaluate the expression of the CD11b/CD18 adhesion mole cule on lymphocytes, monocytes, and granulocytes during HD in 10 patients, using flow cytometric analysis. The study protocol included the measurement of molecule expression using cellulose membrane (Clirans RS15, TERUMO Corp. Japan), and the same membrane coated by vitamin E (Exce brane, Clirans E15, TERUMO Corp., Japan) during 20 dialysi sessions each. Lymphocyte CD11 b/CD1 8 (Mac-1) expression did not change with either dialyzer type. However, monocyt (p = 0.046) and granulocyte (p = 0.018) CD11b/CD18 ex pression in the post HD period was significantly lower using the vitamin E coated membrane compared with the contro cellulose membrane. Our findings suggest a significant de crease in activation and migration of monocytes and granu locytes when using a vitamin E coated cellulose membrane.