Influence of the surface area of different dialysis membranes on granulocyte adherence and superoxide generation

Granulocyte adherence and superoxide anion generation were investigated in vitro in the presence of dialysis membrane fragments incubated with normal human polymorphonuclear cells. Dialysis membranes made from cellulosic material or non-cellulosic material like polyacrylonitrile, polymethylmetacrylate, and polysulfone were tested. The membrane surface area varied (1-5 cm2) while the membrane surface/polymorphonuclear cells ratio was maintained constant (2 X 10(6) cells/cm2). The contact of polymorphonuclear cells with increasing membrane surface area generated a significant decrease of superoxide anion generation (5-80% of inhibition) and produced an increase of granulocyte adherence (5-52%). This phenomenon was observed for all the tested membranes, whether opsonized zymosan or phorbol myristate acetate were used as stimuli. Similar results were obtained after washing the dialysis membrane or when polymorphonuclear cells were suspended in homologous serum. In vitro exposure of granulocytes to cellulosic or non-cellulosic dialysis membranes caused a surface-area dependent modification of polymorphonuclear functions.