Use of a cytokine-release assay to demonstrate loss of platelet secretory capacity during blood bank processing and storage.

Abstract

The extent to which changes in secretory function contribute to the storage lesion of platelets (PLTs) prepared for transfusion is not well described. To develop a cytokine-release assay for the assessment of PLT secretory capacity during the preparation and storage of PLTs. Small volumes of PLT-rich plasma and PLT concentrate (PC) were prepared from whole blood (WB; N = 4 donors). Aliquots of WB, PLT-rich plasma, and PC were treated with 20 μM adenosine diphosphate or saline (control). Samples of WB-derived PCs obtained from a regional blood center were similarly stimulated at various storage times (N = 10 units). Plasma levels of RANTES (chemokine ligand 5; regulated on activation, normal T cell expressed and secreted) and PLT aggregation were measured following agonist addition. Adenosine diphosphate stimulated RANTES release from PLTs in fresh WB on average by 4.1-fold (P < .001), in PLT-rich plasma by 4.7-fold (P = .002), and in PC by 1.3-fold (P < .001). For blood center PCs, adenosine diphosphate failed to stimulate RANTES release at day 2 of storage or later (P ≥ .31). Baseline RANTES levels in the plasma/supernatant increased 660% during PC preparation (P = .02) and an additional 30% during subsequent storage (P < .001). Mean PLT aggregation decreased during processing from WB (95.6%) to PC (60.5%; P = .04). For blood center PCs, mean PLT aggregation decreased substantially from days 2 (41.0%) to 7 (2.3%; P < .001). A cytokine-release assay revealed a diminution in PLT secretory capacity during PC processing and storage, with complete elimination by day 2 of storage. Loss of PLT aggregability occurred more slowly. The cytokine-release assay may be a useful endpoint for optimizing PLT preparation and storage.