The Effect of Timing of Gammairradiation on Hemolysis And

The effect of timing of gamma-irradiation on hemolysis and potassium release in leukoreduced red cell concentrates stored in SAGM

K. Serrano,1,2,3 D. Chen,2,3 A. L. Hansen,4 E. Levin,1,2,3 T. R. Turner,4 J. D. R. Kurach,4 J. P. Acker4 & D. V. Devine1,2,3 1Canadian Blood Services, Centre for Innovation, Vancouver, BC, Canada 2Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada 3Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada 4Canadian Blood Services, Centre for Innovation, Edmonton, AB, Canada

While irradiation of red cell concentrates (RCC) prevents graft-versus-host disease in susceptible transfusion recipients, it also damages red blood cells (RBC). To understand the ability of irradiation regulations to prevent transfusion of inferior units, we irradiated 980 RCC in saline-adenine-glucose-mannitol (SAGM) using various combinations of pre-irradiation age and post-irradiation storage times, and measured hemolysis and extracellular potassium levels. We observed unac- ceptably high hemolysis (>0Á8%) in some RCC and elevated extracellular potassium levels in all gamma-irradiated RCC. This suggests that more restrictive Received: 19 August 2013, revised 8 October 2013, storage times should be considered for RCC in SAGM. accepted 10 October 2013 Key words: blood components, component production, quality control.

Introduction possible, but no later than 14 days after irradiation and, in any case, no later than 28 days after collection.’ The Gamma-irradiation of red cell concentrates (RCC) reduces British Committee for Standards in Haematology (BCSH) the risk of graft-versus-host disease in immunocompro- has even more restrictive standards, stating ‘Red cells may mised transfusion recipients [1]. However, gamma-irradia- be irradiated at any time up to 14 days after collection, tion also produces reactive oxygen species (ROS) that and thereafter may be stored for a further 14 days.’ [4] We cause lipid peroxidation and membrane damage. This investigated the impact of length of RCC storage before reduces RBC function and viability [2], which may dimin- and after gamma-irradiation on hemolysis and extracellu- ish post-transfusion recovery and lead to adverse post- lar potassium levels. transfusion outcomes. Current AABB gamma-irradiation guidelines, which are Methods also used in Canada, indicate that irradiation may be performed at any time during RCC storage. Irradiated RCC Leukoreduced RCC (n = 896) in saline-adenine-glucose- may be stored up to a maximum of 28 days post-irradia- mannitol (SAGM) were manufactured from whole blood tion. Based in part on a recent study [2], the latest update collected into citrate-phosphate-dextrose. Whole blood of the Council of Europe guide (17th edition) shortened the was leukoreduced at 4–8°C, prior to component produc- allowable post-irradiation storage time for irradiated RCC tion according to Canadian Blood Services standard oper- from 28 days to 14 days. [3] The revised guideline states ating procedures. RCC were stored in PVC-DEHP ‘Red cell components may be irradiated up to 28 days after containers (Fenwal, Lake Zurich, IL, USA). collection. Irradiated cells must be transfused as soon as Red cell concentrates were gamma-irradiated (25 Gy) 8–40 days after collection and subsequently stored for – Correspondence: Dana Devine, Ph.D., Canadian Blood Services, UBC 1 28 days without exceeding total storage time of Centre for Blood Research, 2350 Health Sciences Mall, Vancouver, 42 days [1]. Hemolysis, measured once for each RCC, BC V6T 1Z3, Canada was calculated from hematocrit and total hemoglobin E-mail: [email protected] (Hb) measurements made by a hematology analyzer

1 2 K. Serrano et al.

(ADVIA-120; Siemens, Oakville, ON, Canada) and super- irradiated after 4 weeks due to limited storage time after natant Hb measurements made using a plasma/low irradiation. hemoglobin photometer (HemoCue Inc., Angelholm,€ Swe- Extracellular potassium levels increased rapidly follow- den). All units were irradiated and assayed over the ing gamma-irradiation, reaching levels comparable to course of 29 days. those of non-irradiated 42-day RCC within 3 days of irra- A separate set (n = 84) of similarly produced RCC were diation, regardless of unit age when irradiated (Fig. 2). gamma-irradiated 7, 10, 14, 21, 35, or 40 days post-collec- According to multiple linear regression analysis tion. Testing began 2 days post-irradiation, with daily sam- (r2 = 0Á83), explanatory variables predictive of potassium pling for the first week (excluding weekends), then weekly concentration included length of storage before and after until either 28 days post-irradiation or the 42 day expiry irradiation (P < 0Á001), male gender (P < 0Á001), and of the RCC, whichever occurred first. Extracellular potas- greater donor age (P < 0Á05). sium was measured by indirect potentiometry (DXC 800; Beckman Coulter Inc., Fullerton, CA, USA). Discussion Multiple linear regression analysis was performed on log-transformed hemolysis data using Minitab 16 (Mini- We observed enhanced hemolysis in RCC irradiated later tab Inc., State College, PA, USA). Explanatory variables in storage compared to those irradiated earlier, consistent were considered significant at P < 0Á05. with the reduced antioxidant protective capacity in older RBC [5]. This analysis indicates that adherence to North Results American RCC irradiation guidelines can lead to poor in vitro quality for RBC in SAGM. Units with non-conform- Hemolysis progressively increased with storage time, both ing hemolysis were rarely seen using either Council of before and after irradiation (Fig. 1). Overall, forty RCC Europe guidelines or BCSH standards. While there is some (4Á5%) exceeded hemolysis levels of 0Á8% allowable by indication that storage in different additive solutions (AS) European and Canadian standards. Multiple linear regres- can result in different hemolysis levels [6], evidence is sion analysis (r2 = 0Á53) indicated the length of storage lacking regarding the degree of difference in hemolysis before or after irradiation predicted hemolysis (P < 0Á001) that may exist after gamma-irradiation, if any. Studies as did male gender (P = 0Á015), and greater donor age investigating hemolysis rates of gamma-irradiated RBC in (P < 0Á001). Storage time after irradiation was the most other AS could be considered for regions with less restric- predictive explanatory variable for hemolysis. RCC irradi- tive gamma-irradiation guidelines. ated in their fourth week of storage and subsequently Unlike non-irradiated RCC, which linearly increase stored for 15–21 days exhibited the highest level of extracellular potassium levels over storage time [7], an hemolysis (mean hemolysis = 0Á66 – 0Á44%; 18 units initial sharp increase in potassium was detected following >0Á8%; n = 57). Hemolysis was less pronounced in RCC gamma-irradiation. This further suggests that gamma-

28 (a) (b) AABB Council of Europe (17th edition) 4 0·48 ± 0·18 0·54 ± 0·34 25 (n = 61) (n = 43) British Council on Standards in Hematology 22

0·39 ± 0·22 0·43 ± 0·24 0·66 ± 0·44 19 3 n n n ( = 68) ( = 70) ( = 57) 16 13 0·23 ± 0·12 0·25 ± 0·12 0·39 ± 0·18 0·47 ± 0·29 2 10 (n = 67) (n = 70) (n = 64) (n = 45) >0·8 0·4 – 0·8 Days afterirradiation 7 Weeks afterWeeks irradiation 0 – 0·39 1 0·10 ± 0·06 0·13 ± 0·07 0·24 ± 0·21 0·26 ± 0·17 0·28 ± 0·15 4 (n = 72) (n = 73) (n = 67) (n = 69) (n = 70) 1 23456 1 4 7 1013161922252831343740 Weeks before irradiation Days before irradiation

Fig. 1 Hemolysis levels are inﬂuenced by both age at irradiation and length of storage after irradiation. (a) Mean hemolysis levels (–1 SD) grouped by weeks of pre-irradiation storage and weeks after irradiation. (b) Contour map representation of hemolysis levels in all units tested. The areas enclosed by the boundaries deﬁne the allowable time frames in which red cell concentrates (RCC) may be irradiated and subsequently stored for three different guidelines. Black data points represent units >0Á8% and dark grey data points represent units with hemolysis between 0Á4% and 0Á8%.

70·00

60·00

50·00

40·00 D7 irradiaon 30·00 D10 irradiaon D14 irradiaon D21 irradiaon Fig. 2 Potassium levels after irradiation of red 20·00 D28 irradiaiton blood cells (RBCs) stored for varying times. Supernatant potassium (m) D35 irradiaon Symbols represent different ages at irradiation 10·00 D40 irradiaon D5 average as indicated (n = 12). Potassium levels of non- D42 average irradiated red cell concentrates (RCC) at days 5 0·00 and 42 are included (n = 142). Error bars 11 12 13 14 15 16 17 21 23 24 28 30 31 32 35 37 38 39 42 Days post collecon represent 1 SD of the mean. irradiation compromises RBC membrane integrity, possibly directly affecting Na+/K+-ATPase function [8]. Conflict of interest Such a dramatic increase in potassium levels may escalate The authors declare no conflict of interests. the risk of post-transfusion hyperkalemia and subsequent cardiac complications in neonates or patients requiring massive transfusions [7]. Author contribution The data reported here, which represent the largest DVD conceived the study and edited the manuscript. KS, series in the literature, demonstrate that timing of gamma- DC, and EL designed the detailed study protocol for the irradiation has a significant impact on in vitro RBC quality. large scale irradiation component, executed the study and With notably increased hemolysis and extracellular potas- performed the data analysis; DC wrote the initial manu- sium levels in RCC irradiated late in storage, gamma- script. JPA designed the study protocol for the smaller irradiation guidelines should be examined and potentially hemolysis/potassium study which was executed and ana- revised to avoid transfusion of inferior quality RCC. lyzed by ALH, TRT and JDRK.

References

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