Background: This study aimed to compare platelet (PLT) quality during storage of buffy coat (BC) PLT concentrates (PCs), prepared either manually or by the automated OrbiSac system (Gambro BCT).
Study design and methods: Following overnight storage at 20 to 22 degrees C, five BCs were pooled with 300 mL of PLT additive solution. Twenty-one PCs were produced manually (M-PCs) and 21 by the automated OrbiSac system (A-PCs). Swirling, PLT count, mean PLT volume, blood gas analyses, potassium, glucose, and lactate were assessed. Expression of the activation markers CD42a, CD62P, and PAC-1 was analyzed by flow cytometry on resting PLTs and PLTs stimulated with thrombin receptor agonist peptide (TRAP). Levels of CCL5 and transforming growth factor-beta1 (TGF-beta1) were measured by enzyme-linked immunosorbent assay.
Results: The A-PCs had significantly larger volume and higher PLT yield, PLT recovery, and white blood cell concentration than the M-PCs, whereas the red blood cell content was significantly highest in the M-PCs. pH levels were between 6.9 and 7.2 in all PCs. Neither glucose consumption nor lactate production differed significantly over time. A-PCs had, compared to M-PCs, significantly higher expression of CD62P on resting PLTs, lower capacity for up regulating CD62P on TRAP-stimulated PLTs, and higher levels of CCL5 during storage. TRAP-stimulated A-PCs had a significantly higher potential for down regulation of CD42a than M-PCs. No difference was found in TGF-beta1 levels or TRAP-induced up regulation of PAC-1.
Conclusion: The levels of CCL5 and the expression of CD62P in resting and stimulated PLTs indicate that PLTs in A-PCs are slightly more activated than in M-PCs, but the clinical importance of this finding is yet unknown.