Complement Activation in Plasma Exchange by Single Filtration and Centrifugation and in Cascade Filtration

Abstract

C3d was assayed in samples of blood plasma obtained before and after centrifugation, single filtration or cascade filtration, and also in samples of waste plasma obtained after termination of exchange. In blood plasma, cascade filtration was followed by an increase of the mean C3d concentration from 20 to 50 mU/l (p < 0.001, n = 15), whereas single filtration and centrifugation were followed by a minor decrease. Waste plasma of cascade and single filtration contained 113 ± 42 mU/exchange (n = 15, mean ± SD) and 83 ± 46 mU/exchange (n = 8), respectively. In centrifugation, the concentration of C3d of waste plasma never exceeded that of blood plasma, and the total amount of C3d of waste plasma was only 4 ± 6 mU/exchange. In contrast to filtration, the centrifugation technique seemed not to be afflicted with any increase in the break down of complement component C3.