[Complement activation during storage of preserved blood].

We have provided evidence that during storage of CPD-Al stabilized whole blood factors of the complement cascade get activated. We prospectively measured C3a-desArg, C4a-desArg, and C42C3-activatorcomplex in 30 units of whole blood in the absence and presence of the proteinase inhibitors aprotinin and eglin over a storage period of 28 days. C3a-desArg increased from basic levels of 276 +/- 35 ng/ml to maximal levels of 1922 +/- 218 ng/ml after 2 weeks of storage. Similarly there was an increase in C4a-desArg levels from 172 +/- 16 ng/ml (day 0) to 1483 +/- 221 (day 14), but C4a-desArg levels further increased with time. By contrast C42 C3-activatorcomplex levels increased only moderately from 170 +/- 18 micrograms/ml (day 0) to 207 +/- 13 micrograms/ml (day 28). The addition of aprotinin and eglin could not inhibit the increase in activated complement factors. Our observations might be of clinical importance, especially during massive transfusions, since C3a-desArg in concentrations less than 1 ng/ml enhances the activation of platelets.