Irradiation effect on aging red blood cells

Irradiation of stored red blood cells (RBC) is increasingly utilized for patients who are im m unosuppressed or on chem otherapeutic regimens. W ith the growing dem and for irradiated cellular blood products, there has been an increasing need for transfusion services to store previously irradi­ ated blood until needed for transfusion. The effect of irradiation on aging stored RBC has not been studied to date. Five units each of group A, RBC collected in CPD-Adsol (AS-1) with a prior shelf-life of 10, 20, 30, and 40 days, respectively, w ere divided equally utilizing a sterile docking device and stored at 1 to 6°C. Baseline samples from each bag were obtained for the m easurem ent of extracellular potassium (K+), plasm a free hemoglobin (PFH), total lactate dehydrogenase (LD), and erythrocyte 2,3-DPG activity. One of each pair received 2,000 rads of gamma irradiation. Samples were obtained at 3 and 7 days post-irradiation, and m ultiples of 7 days until expiration. All irradiated units reached a state of K+ equilibrium at 60 to 70 mmol per L irrespective of the length of previous storage w ith an inverse relationship of RBC age at irradiation and the time required to reach the state of equilibrium . Increased K+ leakage from irradiated aging RBC sug­ gests the need for including in vivo studies of cell survival to establish a post-irradiation storage life. Length of storage prior to irradiation had no effect on PFH , LD activity, and 2,3-diphosphoglycerate (2,3-DPG) activity compared to paired controls.