Complement activation products in liquid stored plasma and C3a kinetics after transfusion of autologous plasma.

Background and Objectives Keeping a small stock of liquid plasma readily available for transfusion is common practise in Sweden. We report data on complement activation markers in plasma components during storage in the liquid state and the kinetics of C3a-(desArg) after transfusion of autologous plasma with high content of C3a-(desArg) . Material and Methods Plasma components were prepared by apheresis or from whole blood. C3 fragments (C3a-(desArg) , C3d,g, iC3), and soluble terminal complement complex (sC5b-9) were investigated. C3a-(desArg) kinetics was investigated in regular apheresis donors. Results Apheresis plasma prepared by membrane centrifugation had significantly higher level of C3a-(desArg) , C3d,g and sC5b-9 from day 0 and low iC3, than plasma prepared by other methods. By storage day 7, C3a-(desArg) -levels were above the reference value in 88% of all components. After re-infusion of autologous plasma with high C3a-(desArg) content, there were rapid a(1) and a(2) -distribution followed by a slower b-elimination phase. Conclusion Plasma components prepared by different methods and stored in the liquid phase differ significantly in the amount and timing of complement activation. C3a-(desArg) present in plasma is rapidly eliminated after transfusion. Autologous plasma could be used to study complement kinetics in different clinical situations