Flow cytometry analysis of platelet populations: usefulness for monitoringthe storage lesion in pooled buffy-coat platelet concentrates

Abstract

Background: Early detection of the platelet storage lesion is still a challenge in transfusion practice. Using flow cytometry, we evaluated the appearance of the storage lesion, based on the expression of platelet activation markers, in total platelets and platelet populations.

Materials and methods: Buffy-coat-derived platelet concentrates were stored under standard conditions for 5 days. The expression of activation antigens CD42b, CD36, CD62p and phosphatidylserine on total platelets and populations of small, medium-sized and large platelets was analysed by flow cytometry on storage days 1, 3 and 5.

Results: The activation/lesion on total platelets and each platelet population was detected on storage day 3, by the increased expression of CD36. On the same day, increased expression of CD42b and CD62p was detected, but only on large platelets. Small and medium-sized platelets had increased CD62p expression only on day 5. Externalisation of phosphatidylserine was not detected.

Discussion: Evaluation of the level of expression of various activation markers on different platelet populations could be an additional valid analysis in cell quality control of platelet concentrates, and in the assessment of novel approaches to platelet concentrate manipulation.

Figure 1

The influence of 5 days of liquid storage on platelet subpopulations in buffy coat-derived platelet concentrates (PC-BC). (A) FCS/SSC diagrams of an individual PC-BC. (B) Cumulative results of seven PC-BC. Horizontal brackets indicate a statistically significant change in the percentage of platelets belonging to a particular platelet population; ***p<0.001; **p<0.01.

Figure 2

The expression of platelet membrane antigens CD41 and CD62p in buffy coat-derived platelet concentrates (PC-BC) during 5 days of liquid storage - flow cytometry analysis. Cell count/fluorescence intensity histograms are of one representative PC-BC. Grey plot: day 1; solid line: day 3; dashed line: day 5. The total platelets (plt) and platelet subpopulations with large, medium an small volume were identified based on FSC/log SSC values as it was shown in Figure 1.