PB1052 - Improving platelet function following prophylactic platelet transfusion in patients with hematological malignancies

Background: Platelet transfusion is a standard treatment to prevent bleeding in patients with hematological malignancies. Although transfusions can improve platelet count, their impact on platelet function remains controversial.

Aims: Herein, we used flow cytometry to evaluate and compare platelet function among apheresis platelets in stored bags, pretransfusion, 1 day, and 2 days after transfusion. Through subgroup analysis, we also compared the differences among blood types, CCI, and platelet microparticles.

Methods: We conducted flow cytometry to assess platelet function before and after transfusion and performed subgroup analyses to examine differences based on blood type, Corrected Count Increment (CCI), and platelet microparticles.

Results: Overall, 50 patients who received prophylactic platelet transfusion were enrolled. CD42b expression increased, while CD41 expression decreased after transfusion. Apheresis platelets exhibited the lowest expression of PAC-1 and P-selectin when exposed to agonist stimulations. PAC-1 expression increased under high ADP stimulation, while P-selectin expression increased under both high ADP and thrombin receptor-activating peptide stimulation. In the subgroup analysis, patients with a CCI >4,500 and those with the same blood types exhibited a more significant increase in PAC-1 and P-selectin expression under agonist stimulation. When comparing apheresis platelets collected on different days, only the percentage of platelet-derived microparticles significantly increased.

Conclusion(s): The improvement in platelet function after prophylactic transfusion was noted. Platelet function improved in patients with a CCI >4,500, those with the same blood types as that of apheresis platelets, or PDMP levels < 4.7% more significantly. If transfusion with acceptable compatibility but different blood types, or incompatible blood types, no significant improvement of platelet function was noted. Our results suggest that transfusing platelets with the same blood type remains the optimal choice.