Release of PMN elastase, TGF-β1 and neopterin during blood storage; unfiltered versus filtered blood

Release of inflammatory mediators from blood cells during prestorage leukocyte filtration may result in recipient immune suppression. To investigate the effects of prestorage leukocyte filtration on the quality of blood components, twenty-four blood units were collected from healthy donors and randomised into 3 groups. Eight units were stored as whole blood, eight units were separated into plasma, red blood cells (RBC) and buffy coat and eight units were collected and filtered through the ASAHI RZ 2000 leukocyte filter and separated into plasma and RBC. The units were stored for 35 days. Samples were collected weekly for analyses of polymorphonuclear elastase (PMN elastase), transforming growth factor-β1 (TGF-β1) and neopterin. PMN elastase and neopterin increased during storage of whole blood and RBC. From the beginning and throughout storage, PMN elastase was increased in filtered plasma as compared with unfiltered plasma. Filtration per se did not influence the neopterin concentration in plasma or RBC. TGF-β1 increased in plasma and RBC during storage. In filtered plasma, an elevation of the TGF-β1 concentration was observed from the start of storage. The TGF-β1 levels were higher in filtered plasma compared with unfiltered plasma. Prestorage leukocyte filtration increased the release of PMN elastase and TGF-β1 in plasma and RBC.