Flow Cytometric Measurement of CD41/CD61, CD42b Platelet Receptors and Platelet Factor 3 Activity in Lyophilized Infusible Platelet Membrane Preparation

Background: The short life time of human platelet units has led to a chronic shortage of fresh platelets in blood transfusion centers. Many approaches have been investigated experimentally to produce new hemostatically active platelet products that are capable of long term storage. Infusible platelet membrane (IPM) prepared from fresh or outdated human platelets have been developed as an alternative to standard platelet concentrates with the additional advantage of long shelf life. We aimed to measure the presence of CD41/CD61, CD42b platelet receptors and platelet factor 3 (PF3) activity during IPM preparation.  Methods: After pooling of fresh platelet concentrates, freeze-thawing, washing, formulation and lyophilization steps were performed. Results: Flow cytometric analysis of CD41, CD61 and CD42b after lyophilization of IPM found to be 45.9%, 51.3% and 44.4% with PF3 activity of 39% in contrast to 81.5%, 87.5% and 81.1%, respectively on fresh pooled platelet concentrates with 100% PF3 activity.  Conclusion: The results showed that lyophilized IPM product can preserve major adhesion (CD42b) and aggregation (CD41/CD61) platelet receptors and may retain some PF3 activity at acceptable level which demonstrates hemostatic property of the lyophilized IPM.