Abstract: Objective To analyse the effect of apheresis platelets preservation time on platelet activation and the relationship between individual donor differences and platelet activation status after collection, so as to provide reference for the platelet collection work of blood collection and supply institutions and clinical personalized transfusion. Methods Apheresis platelets from 90 donors in 2023 were randomly collected and preserved for 1, 2, 3, 4 and 7 days in 5 groups. Platelet microparticles (PMPs) and activation index CD62p were detected by flow cytometry in each group and statistically analysed. Data on general physical examination, pre-donation blood test data and collection parameters were collected from each donor and analysed for their relationship with PMPs and platelet activation. The relationship between PMPs and CD62p was analysed. Results The expression rates of CD62p in platelets stored for 1, 2, 3, 4, and 7 days were (61.55±20.17)%, (69.05±13.09)%, (64.63±12.89)%, (70.34±9.504)%, and (84.28±6.303)%, respectively; and the expression rates of PMPs were (6.79±9.17)%, (7.01±9.13)%, (12.37±12.64)%, (7.51±5.70)%, and (17.02±7.20)%; and the number of PMPs (×10³/μL) was 2.69±4.84, 4.80±9.20, 3.59±3.38, 7.94±8.89, and 145.1±190.3, respectively. One-way ANOVA showed that Apheresis platelets from each group of different storage duration CD62p expression and PMPs expression were significantly different (P<0.05). Comparing each group, the CD62p expression rate and the number of PMPs in platelets stored for 7 days were significantly higher than those stored for 1, 2, 3, and 4 days; there was no significant difference between the other groups. Platelet activation rate and the number of PMPs tended to increase with storage time. Pearson's bivariate analysis showed that the number of PMPs initially after platelet collection was positively correlated with donor pulse and leukocyte counts (P<0.05), and there was no significant correlation with other factors; the expression of CD62p was positively correlated with the expression of PMPs (P<0.05). Conclusion Apheresis platelets showed no significant changes in activation and expression of PMPs during the 4-day period of storage, after that, there is an strikingly increase in activation and expression of PMPs (P<0.05). In addition, activation of platelets after collection is associated with individual differences. The appropriate products for clinical application can be selected by the condition of activation and expression of PMPs during platelet storage .

Key words: Apheresis platelet, Platelet microparticles, Platelet activation, Platelet storage, Individual transfusion