INHIBITION OF CYTOKINE ACCUMULATION AND BACTERIAL-GROWTH DURING STORAGE OF PLATELET CONCENTRATES AT 4-DEGREES-C WITH RETENTION OF IN-VITRO FUNCTIONAL-ACTIVITY

BACKGROUND: The potential for bacterial contamination limits the stora ge of platelet concentrates (PCs) at 22 degrees C to 5 days. In additi on, storage of platelets under conventional protocols for longer times (>3 days), in the absence of white cell filtration, has been correlat ed with incidents of cytokine-associated febrile reaction in recipient s. It has been demonstrated that the addition of a reagent mixture of second-messenger effecters allows platelets stored at 4 degrees C to m aintain significant in vitro functional activity. Thus, the effects of 4 degrees C storage on the growth of bacteria and the accumulation of cytokines by the white cell fraction of PCs were analyzed to demonstr ate the benefits of this refrigerated storage system. STUDY DESIGN AND METHODS: The platelet storage solution was added directly to PCs obta ined from the blood bank, and these treated PCs were stored at 4 degre es C without agitation. In parallel, control PCs were stored according to standard blood-banking procedures. On Days 1, 3, 5, and 9, the PCs were measured for the plasma concentrations of cytokines. Treated and control PCs stored at 4 degrees C and 22 degrees C were inoculated wi th low-titer Staphylococcus aureus, and bacterial growth was measured over a 5-day period. RESULTS: Control PCs displayed a time-dependent i ncrease in the plasma concentration of interleukin 6, interleukin 1 be ta, and tumor necrosis factor alpha. These conventionally stored PCs a lso displayed a time-dependent increase in the bacteria titer. In cont rast, the treated PCs stored at 4 degrees C displayed no accumulation of the above cytokines in the plasma fraction and no increase in bacte ria titer above the initial inoculation. CONCLUSION: The storage of PC s at refrigerated temperatures inhibits the accumulation of white cell -produced cytokines in the PCs, an effect that could alleviate cytokin e-associated febrile transfusion reactions. The 4 degrees C storage wa s also bacteriostatic, which indicates that the storage of PCs at that temperature increases safety by decreasing the potential for sepsis. Thus, the ability to store PCs at 4 degrees C may allow extension of t he storage limit beyond 5 days.