The in vitro quality of X-irradiated platelet components in PAS-E is equivalent to gamma-irradiated components.

BACKGROUND: Blood components are irradiated to inactivate lymphocytes in an effort to prevent transfusion-associated graft versus host disease. Although gamma irradiators are commonly used, they are subjected to rigorous health, safety, and compliance regulations, compared with X-irradiators which have the advantage of only emitting radiation while the machine is switched on. While the effects of gamma irradiation on platelet components are well known, there is little or no data comparing the effects of X- and gamma-irradiation on the quality of these components. Therefore, this study examined the in vitro quality of platelet components (pooled and apheresis) following X- or gamma-irradiation. STUDY DESIGN AND METHODS: Whole-blood-derived (pooled) and apheresis platelet components in platelet additive solution (n = 20 pairs for each type) were irradiated (X vs. gamma). In vitro platelet quality was tested prior to irradiation (day 1) and subsequently on days 2, 5, and 7. Non-irradiated components were tested on day 5 in parallel as reference controls. Metabolic parameters, surface expression of glycoproteins and activation markers (CD62P and annexin-V binding), and agonist-induced aggregation were measured. RESULTS: All components met Council of Europe specifications. There were no statistical differences in any in vitro quality measurements between X- and gamma-irradiated pooled or apheresis platelet components. CONCLUSION: X- and gamma-irradiation have similar effects on the in vitro quality of stored blood components, indicating that either technology represents a suitable option for irradiation of platelet components.

Refrigeration of apheresis platelets in platelet additive solution (PAS-E) supports in vitro platelet quality to maximize the shelf-life.

BACKGROUND: Refrigeration, or cold-storage, of platelets may be beneficial to extend the limited shelf-life of conventionally stored platelets and support transfusion protocols in rural and military areas. The aim of this study was to compare the morphologic, metabolic, and functional aspects of apheresis platelets stored at room-temperature (RT) or cold conditions, in either plasma or supplemented with platelet additive solution (PAS). STUDY DESIGN AND METHODS: Double-dose apheresis platelets were collected in either 100% plasma or 40% plasma/60% PAS-E using the Trima apheresis platform. One component from each group was either stored at RT (20-24°C) or refrigerated (2-6°C). Platelets were tested over a 21-day period. RESULTS: The platelet concentration decreased by approximately 30% in all groups during 21 days of storage (p > .05). Cold-storage reduced glycolytic metabolism, and the pH was maintained above the minimum specification (>6.4) for 21 days only when platelets were stored in PAS. The surface phenotype and the composition of the supernatant were differentially affected by temperature and storage solution. Functional responses (aggregation, agonist-induced receptor activation, clotting time) were improved during cold-storage, and the influence of residual plasma was assay dependent. CONCLUSION: In vitro platelet quality is differentially affected by storage time, temperature, and solution. Cold-storage, particularly in PAS, better maintains key metabolic, phenotypic, and functional parameters during prolonged storage.

Extended storage of thawed platelets: Refrigeration supports postthaw quality for 10 days.

BACKGROUND: Cryopreservation of platelets with dimethylsulfoxide (DMSO) at -80°C increases their shelf life from days to years. Once thawed, platelets are stored at room temperature (RT), and the shelf life is limited to 4-6 hours. However, refrigeration (cold storage) may facilitate a prolongation of the shelf life of thawed platelets. STUDY DESIGN AND METHODS: ABO-matched buffy coat-derived platelets (30% plasma/70% SSP+) were cryopreserved at -80°C in 5%-6% DMSO. Paired cryopreserved platelet components were thawed, resuspended in 30% plasma/70% SSP+, and then stored at either 20°C-24°C with agitation (RT) or at 2°C-6°C (cold). In vitro platelet quality was assessed over 10 days of postthaw storage. RESULTS: During postthaw storage, the platelet concentration of RT-stored components decreased significantly more than components in cold storage (Day 10 RT 58 ± 10 × 109 /unit vs Day 10 cold 142 ± 16 × 109 /unit; P < .0001). Cold storage reduced the metabolic rate of thawed platelets. During storage, the surface glycoprotein ([GP] Ibα, GPVI, GPIIb, GPIIIa) and activation marker (P-selectin and phosphatidylserine) profile of cold platelets was closer to freshly thawed platelets (Day 0) than those stored at RT. Thromboelastography (reaction time) demonstrated that the procoagulant nature of cryopreserved platelets was preserved during 10 days of cold storage, while RT-stored thawed platelets displayed a gradual prolongation of the time taken to initiate clot formation. CONCLUSION: Cold storage of thawed platelets preserves the platelet phenotype and function for up to 10 days, compared to thawed platelets stored at RT. Thus, cold storage of thawed platelets may represent a simple approach to extend the postthaw shelf life.