Evaluating apheresis platelets at reduced dose as a contingency measure for extreme shortages.

BACKGROUND: The COVID19 pandemic highlights the need for contingency planning in the event of blood shortages. To increase platelet supply, we assessed the operational impact and effect on platelet quality of splitting units prior to storage. STUDY DESIGN AND METHODS: Using production figures, we modeled the impact on unit numbers, platelet counts, and volumes of splitting only apheresis double donations into three units (yielding ⅔ doses), or all standard dose units in half. To assess quality, eight pools of three ABO/Rh-matched apheresis (Trima Accel) double donations in plasma were split to ⅔ and ½ volumes in both Terumo and Fresenius storage bags. These were irradiated and subject to maximal permitted periods of nonagitation (3 × 8 h) before comparing platelet quality markers (including pH, CD62P expression) to Day 9 of storage. RESULTS: Splitting all double donations into three predicted inventory expansion of 23% overall whereas halving all standard dose units clearly doubles stock. In our study, ⅔ and ½ doses contained 153 ± 15 × 109 (~138 ml) and 113 ± 11 × 109 (~102 ml) platelets respectively. Following storage, higher pH was observed in ⅔ than in ½ doses and in Terumo compared to Fresenius bags. The higher pH was reflected in better quality markers, including lower CD62P expression. Despite the differences, on Day 8 (of pH monitoring at expiry) all ⅔ doses and most ½ doses were ≥pH 6.4. CONCLUSION: A strategy to split apheresis platelets in plasma to lower doses is feasible, maintains acceptable platelet quality, and should be considered by blood services in response to extreme shortages.

Comparison of automated and manual methods for washing red blood cells.

BACKGROUND: We sought to compare the quality of washed red blood cells (RBCs) produced using the ACP215 device or manual methods with different combinations of wash and storage solutions. Our aim was to establish manual methods of washing that would permit a shelf life of more than 24 hours. STUDY DESIGN AND METHODS: Fourteen-day-old RBCs were pooled, split, and washed in one of five ways: 1) using the ACP215 and stored in SAGM, 2) manually washed and stored in saline, 3) manually washed in saline and stored in SAGM, 4) manually washed in saline-glucose and stored in SAGM, and 5) manually washed and stored in SAGM. Additional units were pooled and split, washed manually or using the ACP215, and irradiated on Day 14. Units were sampled to 14 days after washing and storage at 4 ± 2°C. RESULTS: All washed RBCs met specification for volume (200-320 mL) and hemoglobin (Hb) content (>40 g/unit). Removal of plasma proteins was better using manual methods: residual immunoglobulin A in saline-glucose-washed cells 0.033 (0.007-0.058) mg/dL manual versus 0.064 (0.026-0.104) mg/dL ACP215 (median, range). Hb loss was lower in manually washed units (mean, ≤ 2.0g/unit) than in ACP215-washed units (mean, 6.1 g/unit). Disregarding saline-washed and stored cells, hemolysis in all nonirradiated units was less than 0.8% 14 days after washing. As expected, the use of SAGM to store manually washed units improved adenosine triphosphate, glucose, lactate, and pH versus storage in saline. CONCLUSION: The data suggest that the shelf life of manually washed RBCs could be extended to 14 days if stored in SAGM instead of saline.

Washing red cells after leucodepletion does not decrease human leukocyte antigen sensitization risk in patients with chronic kidney disease.

BACKGROUND: Standard leucodepleted blood transfusions can induce the production of human leukocyte antigen (HLA)-specific antibodies, which are associated with longer transplant waiting times and poorer graft outcomes. We hypothesized that additional washing of leucodepleted red cells might reduce antigenic stimulus by removal of residual leukocytes and soluble HLA. METHODS: A retrospective review of HLA antibodies in children with chronic kidney disease stage 4-5 who had ≥ two HLA antibody screens between 2000 and 2009, pre- and post-transfusion, and were HLA antibody-negative at first testing. Patients were divided according to whether they received standard leucodepleted blood or "washed cells". To assess the efficacy of washing methods, total leukocytes were enumerated pre- and post- manual and automated washing of standard leucodepleted red cells that had been supplemented with whole blood to achieve measurable leukocyte levels pre-washing. RESULTS: A total of 106 children were included: 23 received no blood transfusions (group 1), six had washed cells only (group 2), 59 had standard transfusions only (group 3), and 18 had both standard and washed cells (group 4). Sensitization rates were 26, 17, 44, and 44 % in groups 1-4 (p = 0.32). Patients in groups 3 and 4 had more transfusions with red cells, platelets, and plasma products. There was no difference in HLA sensitization risk with washed or standard red cells on analysis of co-variance controlling for platelets and plasma transfusions. The red cell washing study showed no significant reduction in leukocytes using manual methods. Although there was a statistically significant reduction (33 %) from baseline pre-washing using the automated method, from 6.54 ± 0.84 × 10(6) to 4.36 ± 0.67 × 10(6) leukocytes per unit, the majority of leukocytes still remained. CONCLUSIONS: There was no evidence that using washed leucodepleted red cells reduced patient HLA sensitization rates. Washing leucodepleted red cells is unlikely to reduce the risk of HLA sensitization due to the limited effect on residual leukocytes.