Irradiation effect on aging red blood cells.

Irradiation of stored red blood cells (RBC) is increasingly utilized for patients who are immunosuppressed or on chemotherapeutic regimens. With the growing demand for irradiated cellular blood products, there has been an increasing need for transfusion services to store previously irradiated 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, were divided equally utilizing a sterile docking device and stored at 1 to 6 degrees C. Baseline samples from each bag were obtained for the measurement of extracellular potassium (K+), plasma 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 multiples 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 with 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 suggests 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.