A modification of cellulose that facilitates the control of complement activation

Complement activation by Cuprophan hemodialysis membranes has been linked to a variety of pathological sequelae (neutropenia and various cardiopulmonary manifestations) seen in the clinical setting. The modification of reactive surface hydroxyl groups on regenerated cellulose with various dicarboxylic-acid anhydrides has been found to significantly limit the complement-activating potential of these materials. Of the anhydrides tested, maleic anhydride appears to display the most dramatic and consistent diminution of complement activation compared to unmodified cellulose (0-10% of control values for C3b deposition and C3a/C5a production). Current evidence suggests that this maleated derivative facilitates the factor-H control of C3 and C5 convertase activity and thus may help limit complement activation by normal regulatory mechanisms. In addition, this modification may help limit the production of other inflammatory mediators that may result in diminished levels of cellular activation.