Generation of interleukin 8 in stored apheresis platelet concentrates and the preventive effect of prestorage ultraviolet B radiation

BACKGROUND: Several recent studies have reported both the generation of cytokines, including interleukin (IL)-1 beta, IL-6, tumor necrosis factor alpha (TNF-alpha), and IL-8, in the supernatants of stored platelet concentrates (PCs) and the implications of this generation in febrile nonhemolytic transfusion reactions. Prestorage filtration is regarded as highly effective in the prevention of cytokine generation. STUDY DESIGN AND METHODS: Studies evaluated 1) the levels of these cytokines in apheresis PCs during storage, 2) the effects of white cell inactivation by ultraviolet B or gamma-radiation on the generation of cytokines, and 3) the effects of poststorage filtration on cytokine levels. The apheresis PCs were treated by either ultraviolet B radiation (20,000 J/m(2)), gamma-radiation (30 Gy), or filtration. Samples were collected sequentially on various days after storage. Cytokines were determined by enzyme-linked immunosorbent assay. RESULTS: The average white cell count in 15 PCs tested was 2.58 +/- 0.7 x 10(6) per mt (range, 0.7-10 x 10(6)/mL). A detectable level of IL-8 was found at 3 days of storage, and the levels of this cytokine increased progressively with increasing storage time, ranging from 1.6 to 35,280 pg per mt on Day 5 and from 2.7 to 83,601 pg per mt on Day 8. Reverse transcriptase-polymerase chain reaction analysis showed that the level of IL-8 paralleled the expression of IL-8 transcripts. The levels of IL-1 beta, IL-6, TNF-alpha, and monocyte chemotactic protein-1 were very low, even on Day 8. Ultraviolet B-radiated PCs failed to generate IL-8, even at 8 days of storage, whereas levels of IL-8 in gamma-radiated PCs were similar to those in nonirradiated PCs. Poststorage filtration of PCs with a negatively charged polyester filter, but not with a positively charged one, markedly reduced the levels of IL-8. CONCLUSION: Of the cytokines tested, IL-8 had the most evident generation in apheresis PCs during storage. Prestorage inactivation of white cells by ultraviolet B radiation, but not by gamma-radiation, was effective in preventing the generation of cytokines during the storage of PCs.