Abstract
As reported earlier, factors of the complement cascade get activated in CPD-A1-stabilized whole blood. As early as after 10 days of storage under normal blood bank conditions the elevations of the concentrations of C3a-desArg and C4a-des-Arg were highly significant. By contrast, the concentration of the C3 activator complex C4b2b remained unchanged even after 3 weeks of storage. Leukocyte depletion partially inhibited the activation of C4 but had no effect on C3a concentrations. Therefore, cleavage of C4 during storage of whole blood seems to be partially leukocyte-dependent, whereas the activation of C3 is possibly due to the activation of the alternate pathway of the complement system by contact of blood to plastic surfaces. Even though the radioimmunologically measured C3a might be inactive as an anaphylatoxin, these observations are of clinical importance since the inactivated C3a-desArg still possesses biological activities such as activation of platelets which may lead to hypercoagulability and thrombosis.