In vitro assessment of platelet storage lesion in leucoreduced random donor platelet concentrates

Abstract

Background: Currently platelet concentrates (PC) are collected using different synthetic materials and different centrifugation/leucocyte-removal processes. Upon exposure to artificial surfaces and high centrifugation forces, blood cells can undergo various levels of stress-induced, cellular activation/fragmentation and release reactions which may not only influence the extent of the platelet storage lesion but may also contribute to poor clinical effectiveness of the PC and transfusion reactions.

Materials and methods: An array of assays, used for quality control of PC, was performed in two different groups of PC prepared from random donor plasma on days 1, 3 and 5 of storage. The group 1 PC were not leucoreduced while the group 2 PC underwent prestorage leucoreduction using a PL50E filter. As current recommendations for the evaluation of PC include the measurement of platelet activation, in this study CD62P on platelet membrane was measured. Furthermore, in vitro studies indicate that sHLA antigens may modulate immune competent cell function so, the presence of sHLA-1 in blood components is considered a marker of immunological reactivity and this, too, was measured.

Results: The levels of CD62P and sHLA-1 were significantly lower in leucoreduced PC than in non-leucoreduced ones. However, the overall rate of increase of sHLA-1 during storage was faster in the leucoreduced group of PC. No significant differences were detected regarding other assays of quality.

Conclusion: Based on our findings, leucoreduced PC differ from non-leucoreduced ones in terms of some specific markers such as CD62P as a marker of platelet activation and sHLA-1 as a marker of immunological reactivity. Pre-storage leucofiltration, followed by storage in currently used plastic bags is a safe procedure for PC for up to 5 days. The available leucoreduction technologies are not, however, sufficiently robust to completely abrogate transfusions reactions, and improvements are required to reach the goal of optimised yield and minimal transfusion reactions with platelet therapy.

Keywords: CD62P; platelet concentrate; platelet storage lesion; sHLA-1.

Figure 1

CD62P expression as a marker of platelet activation in the two studied groups of platelet concentrates (PC) on days 1, 3 and 5 of storage. Group 1: PC that did not undergo WBC reduction; group 2: PC that underwent pre-storage WBC reduction

Figure 2

The significance of difference of CD62 expression % between group1 and group 2 at day 1, 3 and 5

Figure 3

The significance of difference of HLA-G level (units/mL) between group1 and group 2 at day 1, 3 and 5