Neutrophil behavior during hemodialysis. Role of membrane contact.

The neutrophil dysfunctions observed transiently during dialysis have been attributed to systemic down-regulation of the cells by activated complement. The in vivo effect of membrane contact on oxygen radical production and chemotaxis of dialyzed neutrophils isolated simultaneously from the arterial and venous sites during dialysis with cuprophane, polycarbonate, polysulfone, and polyacrilonitrile membranes was studied. Cells remaining in circulation after 15 min of dialysis showed defective responses only when collected at the venous site of the cuprophane dialyzer, in spite of a similar leukopenia at the venous and arterial sites. With the other membranes tested, no defects in neutrophil functions were evidenced. These results suggest that down-regulation occurs within the dialyzer and that, besides complement activation, the membrane plays an additional role.