Blood collection technique and processing impact the nucleosomes and complement contents of platelet products.

Background and objectives: Platelet concentrates (PCs) available for transfusion are prepared either from whole blood donations or by platelet aphaeresis procedures. These different preparation methods may potentially affect damage-associated molecular patterns (DAMPs) and complement activation products in PC, which are associated with adverse reactions (ARs).

Materials and methods: The objective of this study is to perform a comparison of platelet activation, nucleosome, mitochondrial DNA (mtDNA), haem and complement activation between differently produced leukoreduced PC. Single donor aphaeresis-PC stored in either plasma or platelet additive solution (PAS)-E and pooled buffy-coat (BC)-PC stored in PAS-E were produced in a regional setting of the Dutch Blood Establishment. For BC-PC, a pool of five BC-independent donors was used, and BC-PCs were grouped based on the time of donation (morning vs. afternoon). Directly after production, samples were collected from PC, and CD62P+ platelets, nucleosomes, mtDNA, haem and complement activation products were measured. A comparison was made between aphaeresis-PC and BC-PC.

Results: Higher levels of CD62P+ platelets were observed after stimulation in aphaeresis-PC than BC-PC. The levels of nucleosomes and C4b/c were significantly increased in BC-PC compared to aphaeresis-PC. In addition, the levels of elastase-α1-antitrypsin complexes (EA) were higher in BC-PC from morning blood collections than in aphaeresis-PC or BC-PC from afternoon blood collections, which indicates increased neutrophil activation.

Conclusion: Aphaeresis-PC can be better activated than BC-PC. BC-PC contains higher levels of nucleosomes and EA, most likely due to the presence of neutrophils in the BC. In addition, higher levels of complement activation products were observed in BC-PC.