CYTOKINE GENERATION IN STORED PLATELET CONCENTRATES

Background: Cytokines, because of the nature of their immunoinflammato ry actions, are potential mediators of the symptom complex of nonhemol ytic transfusion reactions. One possible source of cytokines in the tr ansfusion setting is the stored blood component itself. Study Design a nd Methods: To test this possibility, the plasma portion of stored pla telet concentrates (PCs) was assayed for the presence of interleukins 1 beta (IL-1 beta), 6 (IL-6), and 8 (IL-8) and tumor necrosis factor a (TNF-alpha). Samples were taken from PCs obtained from the inventory of a regional blood center (n = 120; 30 each of 2-, 3-, 4-, and 5-day- old units). Results: Detectable levels of IL-8 were measured in 59 per cent of the PCs sampled, ranging from 30 percent of the 2-day-old unit s to 83 percent of the 5-day-old units. The median IL-8 concentration ranged from undetectable levels in 2-day-old units up to 1100 pg per m L in 5-day-old units. The mean IL-8 concentration in 5-day-old units, 11,600 pg per mL, was 100 times the mean for 2-day-old units, which wa s 116 pg per mL (p<0.0001). The highest levels of IL-8, 50,000 to 200, 000 pg per mL, in general were found in units with the longest storage times and highest white cell counts. Sequential sampling of 17 indivi dual PCs over 7 days of storage confirmed that IL-8 increases progress ively with increasing storage time. Parallel, but smaller, increases i n IL-1 beta were observed in those units with high IL-8 concentrations . TNF-alpha was detected in 3 (10%) of 30 five-day-old PCs, but never exceeded 55 pg per mL in any unit tested. IL-6 at levels of 740 and 50 8 pg per mt was detected in two 5-day old units with high white cell c ounts of 9500 and 14,800 per mu L, respectively, but not in 21 additio nal units tested with white cells less than or equal to 9200 per mu L or storage time of less than or equal to 2 days. White cell reduction by third-generation filters on Day 1 of platelet storage prevented the generation of IL-8 and IL-1 beta to Day 5 of storage. Conclusion: Alt hough 11-8 achieved levels in some units of PCs that appear capable of causing physiologic changes, the potential adverse effect on transfus ion recipients of the infusion of cytokines in PCs remains to be inves tigated.