Evaluation of platelet activation in leukocyte-depleted platelet concentrates during storage.

Structural and functional changes in platelets during storage can lead to the loss of platelet reactivity and response. Our aim was to evaluate leukocyte-depleted platelet concentrates on storage days 0, 3 and 5, obtained by in-line filtration. In non-filtered platelet concentrates (NF-PC) group, 180 whole blood units were collected with quadruple blood bags and then compared to another group of 180 whole blood units (leukocyte-depleted platelet concentrates [LD-PC]), collected in Imuflex Whole Blood Filter Saving Platelets (WB-SP) bags with an integrated leukoreduction filter, with regard to the platelet quality and characteristics. The efficacy of the two techniques for platelet concentrate preparation was evaluated by white blood cell (WBC) and platelet count on day 0. The partial pressure of oxygen (pO2), pH, platelets positive for P-selectin (CD62P), CD63, cluster of differentiation 42b (CD42b), phosphatidylserine (PS), and mitochondrial membrane potential (MMP) were analyzed during the storage in both groups. A significantly lower WBC count and higher platelet count was observed in LD-PC compared to NF-PC group, indicating the overall efficacy of the first technique. During the 5-day storage, pH and pO2 decreased in both groups. In LD-PC group, higher pH, increased pO2 and decreased platelet surface expression of CD62P, CD63 and PS were observed compared to NF-PC group. In both groups, the percentage of CD42b positive platelets and MMP did not change significantly during the 5-day period. The assessment of different markers of platelet activation may be an effective tool in evaluating the quality of platelets during storage. A better understanding of platelet activation may provide new insights for developing a novel therapeutic approach in the manipulation of platelet aggregation.