Platelet Recruitment during Multiple Donor Platelet Apheresis Differs between Cell Separators

Abstract

Background: Recruitment of platelets (PLT) during donor PLT apheresis may facilitate the harvest of multiple units within a single donation. Methods: We compared two PLT apheresis procedures (Amicus and Trima Accel) in a prospective, randomized, paired cross-over study in 60 donors. The 120 donations were compared for depletion of circulating PLT in the donors, PLT yields and PLT recruitment. A recruitment was defined as ratio of total PLT yield and donor PLT depletion > 1. Results: Despite comparable differences of pre- and post-apheresis PLT counts (87 × 10⁹/l in Trima Accel vs. 92 × 10⁹/l in Amicus, p = 0.383), PLT yields were higher with Trima Accel (7.48 × 10¹¹ vs. 6.06 × 10¹¹, p < 0.001), corresponding to a higher PLT recruitment (1.90 vs. 1.42, p < 0.001). We observed a different increase of WBC counts after aphereses, which was more pronounced with Trima Accel than with Amicus (1.30 × 10⁹/l vs. 0.46 × 10⁹/l, p < 0.001). Conclusion: Both procedures induced PLT recruitment. This was higher in Trima Accel, contributing to a higher yield in spite of a comparable depletion of circulating PLT in the donors. This recruitment facilitates the harvest of multiple units within a single donation and seems to be influenced by the procedure utilized. The different increases of circulating donor white blood cells after donation need further investigation.

Recruitment of platelets, white blood cells, and hematopoietic progenitor cells during high‐yield plateletpheresis

“…Our data may theoretically not exclude a potential systematic underestimation of the effective donor blood volume, but we consider an underestimation in the order of one‐third from the formula of Nadler and Allen used in the Trima Accel very unlikely 13 . The observation of a significant increase of the mean PLT volume during plateletpheresis in PLT donors 5 also supports the hypothesis of a release of PLT in the circulation from an extravascular site. The origin of the PLT recruited is not primarily addressed by our study, but this aspect does not affect the development of a plateletpheresis prediction algorithm for healthy PLT donors.…”

“…Furthermore, our observations in a previous study have also suggested an increase of circulating white blood cells (WBCs) in the donors at the end of plateletpheresis 5 . This may be related to an unknown common mechanism recruiting blood cells in general during apheresis or to the accumulation of WBCs in the extracorporeal system during the procedure, followed by their return to the donor at the end of the procedure.…”

“…A p value of less than 0.05 was considered significant. Based on a previous study, 5 a sample size of 20 donors had been calculated to detect a recruitment of 1.4 with α error 5% and β error 10%.…”

“…However, this prediction of a PLT post does not account for several aspects of the procedural complexity. First, some studies suggested a recruitment of PLT during plateletpheresis, defined as a ratio more than one of the effective and the predicted PLT yield based on donor blood volume and difference between PLT pre and PLT post 5,6 . If PLTs are recruited into the donor blood circulation during apheresis, the effective PLT post will be higher than conservatively predicted, and the limit setting required by the FDA may be applied too restrictively with current algorithms 7 .…”

Evaluation of store lesion in platelet obtained by apheresis compared to platelet derived from whole blood and its impact on the in vitro functionality

“…On the other hand, platelet activation could be dependent in part in the apheresis equipment used. Bueno et al (2005) [44] reported that the in vitro activation of platelets can vary, depending on the centrifugation rotor and the re-suspension method.…”