Viability and in vitro properties of AS-1 red cells after gamma irradiation

BACKGROUND: Irradiation has been shown to adversely affect both in vivo 24- hour recovery (recovery [%]) and in vitro properties of stored red cells (R BCs). There is uncertainty as to how these changes are related to the day o f irradiation and the length of storage after irradiation. STUDY DESIGN AND METHODS: Four protocols used day of irradiation and storag e time after irradiation as the independent variables. At the conclusion of the storage period, viability was measured with radiolabeled RBCs as the r ecovery and the long-ten survival time for RBCs that were circulating beyon d 24 hours. In addition, in vitro values including RBC ATP, hemolysis level , and supernatant potassium were measured. Each subject donated 2 units of whole blood (CPD) and received autologous irradiated and untreated control RBCs (AS-1) on two separate occasions. RESULTS: Reduced recovery in irradiated units was noted when compared to th at in control units, and the reduction was most apparent with long periods of storage after irradiation, irrespective of the day of irradiation. With irradiation on Day 1 of storage and a total storage period of 28 days, mean +/- SD recovery (single label) was 84.2 +/- 5.1 percent for control RBCs a nd 78.6 +/- 5.9 percent for irradiated RBCs (n = 16; p<0.01). With irradiat ion on Day 14 and storage through Day 42, the recoveries were 76.3 +/- 7.0 percent for control RBCs and 69.5 +/- 8.6 percent for irradiated RBCs (n = 16; p<0.01). Less reduction in recovery was observed with shortening of the postirradiation storage time. When the total storage period was reduced to 28 days after Day 14 irradiation,the recoveries were not significantly dif ferent. With an additional 2-day storage period after irradiation on Day 26 , the recoveries were also comparable. Longterm survival times for control and irradiated RBCs were not significantly different in any of the four pro tocols. RBC ATP levels and hemolysis were minimally, but significantly infl uenced by irradiation. Supernatant potassium levels, however, were substant ially increased after irradiation in each of the four protocols. CONCLUSION: Irradiation has only a small effect on the properties of RBCs t reated and stored according to the utilized protocols. Longer storage times after irradiation resulted in progressively reduced recovery while long-te rm survival remained unaffected.