Complement Metabolism During Membrane Plasma Separation

Abstract

Because some plasma separator membranes can activate complement in serum, the behavior of [human] complement during actual membrane plasmapheresis was studied. Complement metabolism in subjects undergoing membrnae plasma separation with 3 different prototypic devices was studied. Complement activation was judged by crossed immunoelectrophoretic analysis of C3 [complement component 3] in plasma. A cellulose acetate separator employed with heparin as the anticoagulant caused extensive C3 conversion (up to 50%) in separated plasma. A polysulfone separator used with citrate, and a polyvinylchloride derivative separator employed with heparin plus citrate, caused only small amounts of C3 conversion (0-10%) in separated plasma. C3 conversion in the cellulose acetate separator was reduced when citrate was included in the anticoagulant regimen, whereas C3 conversion in the polyvinylchloride derivative separator was increased when citrate was omitted. Activation of complement by the membrane material may occur during membrane plasma separation. Selection of membranes judged weakly activating by in vitro screening and the use of citrate anticoagulation would appear to minimize complement activation in membrane plasma separators.