Effects of dialysis membranes on the kinetics of tumor necrosis factor-α production by peripheral mononuclear cells in chronic hemodialysis patients

To evaluate the biocompatibility of dialysis membranes, blood samples were collected from 10 hemodialysis patients immediately before dialysis and peripheral blood mononuclear cells were isolated The 3.0 x 10(5) cells/ml were then passed 30 times through modules made of a polyethylene glycol-grafted cellulose membrane, a polyacrylonitrile membrane, and a polysulfone membrane. Expression of messenger RNA for tumor necrosi factor-alpha (TNF-alpha) was determined. Cells were also cultured for 2 h with and without lipopolysaccharide and TNF-alpha levels in the supernatant were measured. TNF-alpha messenger RNA expression was significantly higher immediately after passage through the polyacrylonitrile membrane compared with the other membranes. Cells cultured without lipopolysaccharide, produced significantly less TNF-alpha after passage through the polysulfone membrane, while lipopolysaccharide significantly increased TNF-alpha production by cells passed through the polyacrylonitrile membrane. These results suggest that biocompatibility differs even among dialysis membranes believed to cause no complement activation.