Studies on the preservation of red blood cells. Attachment of the third component of human complement to erythrocytes during storage at 4 degrees C.

Utilizing an automated antiglobulin test, we have investigated the presence of the third and fourth components of human complement on normal red blood cells (RBCs). Only negligible amounts of the fourth component, C4, could be detected on either freshly collected or stored RBCs. The fragment C3d of the third component, C3, was detectable on both freshly collected and stored normal RBCs. A product derived from C3 and reacting with anti-C3c antibody was only barely detectable on freshly collected normal RBCs. During storage of blood at 4 degrees C, increasing quantities of this material were detected on the RBC membrane. Bromelin treatment rendered stored RBCs completely nonreactive with anit-C3c antibody, whereas only partial loss of reactivity was observed following incubation with heated plasma. In contrast, incubation of EC43 with heated plasma completely abolished their ability to react with anti-C3c antibody. We suggest that the presence of this C3 fragment on stored RBCs may contribute to the development of "preservation injury".