Effect of gamma irradiation on cytokines released by platelets during storage

Most published gamma irradiation studies are on the cytokines secreted by leucocytes than platelet cytokines. If cytokines secretion is suppressed by irradiation then it will be an important application of irradiation. To know this we planned to measure cytokines like Regulated upon activation normal T cells expressed and secreted (RANTES), platelet factor 4 (PF-4), Transforming growth factor βeta1 (TGF-β) and βeta Thromboglobulin (β TG) during the storage of irradiated (IR) and non-irradiated (NI) platelets. Ten platelet concentrate (PCs) were prepared using platelet rich plasma and buffy coat methods each and 10 by apheresis on Trima Cell separator. Each PC was transferred in a transfer bag and IR at about 25 Gy and stored at 22 °C in platelet agitator. Samples were taken from NI and IR bag each on 0 day, 3rd day and 5th day from supernatant for cytokine analysis. The samples were stored below −50 °C for cytokines assays using commercial ELISA kits. RANTES levels were in the range of 12–400 ng/ml on 0 day and increased to 108–800 ng/ml on 5th day in NI platelets and 104–800 ng/ml in IR platelet. PF4 increased from 0 day to 5th day showing levels 300–1500 ng/ml in both types of PC. β-TG range was 748–5258 ng/ml in NI and 878–4638 ng/ml in IR platelets on 5th day. TGF-β1 increased up to 780–38431 pg/ml in NI and 461–50,000 pg/ml in IR PC. The study showed that comparison of cytokine levels during the storage in NI and IR platelets was not significant by Mann–Whitney U- test (p > 0.05). Significant increase was observed in these cytokine levels from 0 day to 3rd and 5th day in NI as well as IR samples by Wilcoxon Signed- Rank test (p < 0.05).