Specific antibodies enhance alternative complement pathway activation by cuprophane.

Cuprophane activates the human alternative complement pathway. We have observed that the extent to which the alternative pathway was activated in the presence of fixed amounts of cuprophane in vitro greatly differed between individuals. Several lines of evidence indicated a role for anti-dextran antibodies in determining the extent of alternative pathway activation by cuprophane in whole serum: (1) alternative pathway activation by cuprophane was directly related to the extent to which it was activated by Sephadex in a given serum; alternative pathway activation by Sephadex was previously shown to be antibody-dependent; (2) alternative pathway activation by cuprophane was related to the serum titre of anti-dextran IgG antibodies; (3) adsorption of serum with Sephadex or cuprophane reduced the ability of the serum to be activated in the presence of fresh cuprophane. These results suggest that measuring serum values of anti-dextran antibodies may be potentially helpful for evaluating patients at increased risk of complement activation during haemodialysis with cuprophane membranes.