Inhibition of cytokine synthesis by photochemical treatment and gamma irradiation. The synthesis of cytokine IL-8 was measured after 5 days of storage in pooled random donor platelet concentrates treated separately with S-59, AMT, or 8-MOP plus 1.9 Joules/cm2 UVA, and 2,500 cGy gamma radiation. The level of IL-8 measured on day 0 before treatment served as a baseline measurement. IL-8 levels increased significantly after 5 days of storage in untreated platelet samples. Photochemical treatment with 150 μmol/L S-59 or AMT completely inhibited IL-8 production during storage. Low levels of IL-8 were present after treatment with 75-μmol/L 8-MOP. A partial reduction in IL-8 production was obtained after 2,500 cGy gamma radiation. Each data point is the average of duplicate ELISA measurements. Error bars indicate the standard deviation which is only significant for the untreated and gamma groups after 5 days of storage (error bars for the other groups are not large enough to resolve on the scale in this figure). The data shown is from a representative of five experiments.
