To study the influence of contaminating leukocytes on the storage conditions of platelet concentrates (PC), various amounts of leukocytes were added to identical PC. From 12 blood donations, 12 leukocyte-poor PC were prepared and pooled. Subsequently, the pool was divided into 12 identical PC. The plasma volume of the PC was 58.6±0.6 ml, the platelet concentration was 1.01±0.04x10^9/ml (mean ± SD) and the red cell contamination did not exceed 10^7 per PC. To 4 groups of 3 PC, pooled leukocytes were added from the same 12 blood donations. The leukocyte contamination for each group of 3 PC was 0.14±0.05, 1.96±0.09, 5.53±0.98 and 13.0±0.93x10^6/ml (mean ± SD) for groups I-IV, respectively. The PC were stored for 7 days at 22 °C in normal polyvinylchloride bags. A significant correlation was found between increasing concentrations of leukocytes in the PC and the drop in pH (r=-0.93), glucose consumption (r=-0.91), lactic acid production (r=0.93) and release of lactate dehydrogenase (r=0.92) during storage of the PC. The excretion of β-thromboglobulin, depletion of platelet adenine nucleotides, decreased ability to incorporate 3H-adenosine into metabolic nucleotides and poor morphology of the platelets were also significantly correlated with an increased number of leukocytes in the PC. These data show that high concentrations of leukocytes in PC have a significant detrimental effect on the viability of platelets during storage at 22 °C. We conclude that for good storage conditions of PC, the upper limit of leukocytes per PC should not exceed 10^7.

Storage of leukocyte-poor red cell concentrates (LP-RCC) was investigated after filtration in a closed system that was assembled using a Sterile Connection Device (SCD). The LP-RCC were stored for up to 6 weeks following filtration with either 0.9% saline solution (n = 14) or saline-adenine-glucose-mannitol (SAG M) solution (n = 15) to prime and rinse the cellulose acetate filter. The results were compared with the data of nonfiltered buffy-coat-poor red cell concentrates (BC-poor RCC) stored in SAG M solution (n = 10). All LP-RCC contained less than 10^6 leukocytes whereas the nonfiltered BC-poor RCC contained 675±286x10^6 leukocytes at day 1, decreasing to 83±49x106 at day 42. Although glucose consumption, lactic acid production and decrease in pH was similar from day 7 through 28 in both groups of LP-RCC, a significantly steeper decline of ATP values as well as a higher hemolysis and LDH release was observed in the LP-RCC filtered with saline. During storage of the nonfiltered BC-poor RCC in SAG M, significantly higher glucose consumption (p<0.01), LDH release (p<0.001), rate of hemolysis (p<0.001) and a lower pH (p<0.001) were found, compared to the filtered units. It is postulated that the leukocytes present in the nonfiltered BC-poor RCC were responsible for these differences. The ATP values in the SAG-M-filtered and nonfiltered BC-poor RCC in SAG M were comparable. By comparing the ATP levels and values of the filtered RCC and the nonfiltered BC-poor RCC we conclude that the LP-RCC can be stored for 35 days if SAG M solution is used to prime and rinse the filter.

The effect of rapid cooling to 20-24 °C of whole blood immediately after collection, using ‘cooling units’ with butane-1,4-diol and prolonged storage up to 24 h at ambient temperature was investigated in the whole blood and the subsequently prepared plasma, buffy coat and buffy-coat-poor red cell concentrate (BC-poor RCC) in saline-adenine-glucose-mannitol (SAGM) solution. Factor VIII:C content of the plasma (n=10), after 24 h storage was 80 ± 3% of the initial value. In routine procedures factor VIII:C content in the plasma (n= 129 pools of 20 donor units plasma) was 0.77 ±0.078 IU/ml, after storage of the whole blood for 16-20 h. In whole blood (n=10), the 2,3-diphosphoglycerate (2,3-DPG) content of the red cells decreased from 4.36 ±0.55 to 1.47 ±0.6 pmol/ml red cells after 24 h storage at 20-24°C. After storage of the BC-poor RCC (n=10) at 2-6°C for 1 week, the 2,3-DPG had dropped to 0.76 ±0.46 pmol/ml red cells. During the first 24 h of storage of whole blood, the adenine triphosphate (ATP) levels of the red cells remained stable. A mean increase of 20% of the initial value was observed after addition of SAG M solution. In the BC-poor RCC the ATP slowly decreased to 81 ± 5% after 5 weeks and to 68 ± 6.6% of the initial value after 6 weeks storage. In citrate-phosphate-dextrose blood the yield of platelets in the buffy coat was found to be 84±6% (mean ± SD) of the original value when whole blood (n= 12) was stored for 16-20 h at 20-24°C, as compared to 76 ± 18%, when buffy coats were prepared within 3 h after collection of whole blood without rapid cooling (n= 12). Rapid cooling of whole blood to 20-24°C immediately after collection and subsequent storage of the whole blood up to 24 h contributes to the quality and standardization of the subsequently prepared blood components and will diminish processing at irregular hours.