Surface antigen expression and platelet neutrophil interactions in haemodialysis

Background: There is increasing evidence to show the clinical implications of membrane biocompatibility in haemodialysis therapy. Methods: We conducte d a crossover clinical study examining the clinical biocompatibility profil e of three derivatised cellulosic membranes obtained by means of different modifications to the cellulose polymer (haemophan, cellulose diacetate, ben zyl cellulose) in comparison to the parent polymer (cuprophan) and a refere nce synthetic membrane (polysulfone). Results: In terms of leukopenia produ ction, derivatised cellulosic membranes were generally intermediate between cuprophan and polysulfone, haemophan being more marked than the other two membranes. Upregulation of CD11b/CD18 molecule on neutrophils was found wit h all membranes, to a greater extent with the dialyser containing cuprophan . The expression of CD11b/CD18 on monocytes was slightly affected with cupr ophan only. The neutrophil and monocyte counts throughout the entire dialys is session showed a much better correlation with the cellular expression of sialyl-Lewis x (CD15s) molecule than with CD11b/CD18 expression. An increa sed formation of platelet-neutrophil coaggregates occurred at 15 and 30 min during dialysis with all membranes but benzyl cellulose, the increase with cuprophan being higher than with the other membranes. In concomitance with the increase in platelet-neutrophil coaggregation, an increased hydrogen p eroxide production by neutrophils occurred, which proved to be significantl y higher compared to the unchanged neutrophil hydrogen peroxide production during HD with benzyl cellulose. Conclusions: Our results demonstrate that derivatised cellulose is associated with a considerable improvement in the clinical biocompatibility profile. Derivatised cellulosic membranes show ma ny similarities but also several significant differences which very likely stem from the different type of structural modification to the cellulose po lymer rather than from the degree of hydroxyl group replacement.