Biotinylation of human platelets is compatible with pathogen inactivation treatment and cold storage for clinical studies.

Background: Production of platelet concentrates (PCs) involves several steps that significantly affect platelet behavior. To gain a deeper understanding of how storage conditions impact donor platelet recirculation and functionality post-transfusion, ex vivo platelet labeling is a feasible approach. However, before pursuing clinical investigations of platelet recirculation and function in humans, we aimed to determine the effects of pathogen inactivation technology (PIT) and storage conditions (4°C vs. room temperature [RT]) on phenotype and function of biotinylated platelets compared to conventional PIT PCs for transfusion.

Methods: Nine PCs were prepared in 61% additive solution from 45 buffy coats (five buffy coats each). A pool-and-split of three units was used to prepare three equivalent PCs: two labeled with biotin and stored at RT or 4°C, and one without labeling and stored at RT. All PCs were then treated by PIT (amotosalen/UVA) and stored for 14 days. Labeling efficiency, platelet concentration, metabolic parameters, aggregation response (ADP, collagen, co-aggregation with epinephrine), and platelet phenotype (CD42b, CD62-P, phosphatidylserine) at the basal stage and upon stimulation (ADP or TRAP-6) were performed.

Results: Labeling efficiency of PIT and 4°C PCs was stable over 14 days of storage. Differences in platelet function and phenotype were mainly due to the storage temperature and not the biotinylation process. Phenotypes at baseline or after stimulation were equivalent in biotin-positive and biotin-negative platelets.

Conclusion: Biotin-labeled platelets can effectively enable investigation of the effects of PIT and storage temperature for clinical studies. This method shows great potential for improving platelet transfusion knowledge.