Platelet storage lesion of WBG-reduced, pooled, buffy coat-derived platelet concentrates prepared in three in-process filter/storage bag combinations

BACKGROUND: With the implementation of universal WBC reduction in the Unite d Kingdom, in-process WBC-reduction filters for pooled buffy coat (BC)-deri ved platelet concentrates (PCs) are used in routine production. The effects of three filter/storage bag combinations on platelet activation and mi-cro vesiculation and on the activation of coagulation were investigated. STUDY DESIGN AND METHODS: Using pooled BCs from the same donors, three filt er/storage bag combinations (Autostop BC/CLX, Fall Biomedical; Sepacell PLX 5/PL2410, Asahi Medical; and Imugard III-PL 4P/Teruflex, Terumo) were compa red with unfiltered controls for their effects an microvesiculation and oth er storage-induced changes in platelets. Process efficiency was measured by platelet yield and residual WBC count. The storage changes were assessed: pH, activation of platelets measured by CD62P on the platelet surface and i n supernatant plasma, quantitation of platelet-derived and RBC-derived micr ovesicles, cellular injury measured by annexin V in the supernatant plasma, and activation of the coagulation system measured by kallikrein-like and t hrombin-like activities, prothrombin fragment 1+2, and thrombin-antithrombi n complex. RESULTS: All three filters were comparable in terms of platelet recovery an d WBC removal, and none induced immediate platelet activation or microvesic ulation. With storage, platelet activation or microvesiculation increased i n platelets prepared by all three filters and in unfiltered controls, but t hese effects were significantly less in the Imugard PCs than in controls. T hese findings were consistent with those for annexin V in the supernatant p lasma, which were lower in Imugard PCs than in other products. Sepacell and Imugard filters reduced RBC-derived microvesicles to 50 percent of control levels, but the Autostop filter had no effect. On storage, levels of RBC-d erived microvesicles in filtered products remained static, but levels in th e unfiltered control doubled. Kallikrein- and thrombin-like activities were generated only by the Autostop filter without any further increment on sto rage. CONCLUSION: WBC-reduced pooled BC-PCs prepared by various filter/bag combin ations were equivalent on Day 1 but differed during storage in terms of pla telet activation or microvesiculation.