BACKGROUND: Studies suggest that washing red cell concentrates (RCCs) to remove soluble mediators and/or inflammatory components, such as extracellular vesicles (EVs), may lead to better clinical outcomes. This study tested the hypothesis that non-red blood cell (RBC) generated vesicles in RCC are potent inflammatory mediators in vitro and washing RCCs can reduce these vesicles and subsequently decrease the inflammatory activity of RCCs.From the

Monocytes from pooled cryopreserved BC PBMNCs can be used reliably to evaluate phagocytic responses of sensitized RBCs and to assess clinical significance of RBC alloantibodies.

Background and objectives Blood donor characteristics significantly affect the pre-storage and post-storage quality of red cell concentrates (RCCs). This study investigated the impact of donor age and sex on RCC characteristics and the effect of RCC supernatants on the vascular endothelium and monocytes.Materials and methods RCC units selected from four donor groups based on donor age and sex (male ≤ 30-years old (yo), male ≥ 60-yo, female ≤ 30-yo and female ≥ 60-yo) were stored at 1-6°C and tested on day 7, 21 and 42. RCC supernatants were analysed for the number, concentration and size of extracellular vesicles (EVs). Human vein endothelial cells (HUVECs) monolayers were incubated with RCC supernatants and assessed for expression of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin by flow cytometry as well as endothelial permeability using a trans-epithelial-electrical-resistance assay. Monocytes and HUVECs were incubated with RCC supernatants and supernatants assayed for cytokines/chemokines. ResultsRCCs from female donors were found to have lower unit volume, haemoglobin content and haematocrit compared to RCCs from male donors (P < 0Á05). RCC supernatants from female ≥ 60-yo had a higher concentration of large EVs (≥200 nm) compared to both male ≤ 30-yo (P = 0Á039) and male ≥ 60-yo supernatants (P = 0Á019). Treatment with RCC supernatants from male ≤ 30-yo donors induced lower expression of VCAM-1, lower cytokine/chemokine release and showed the least effect on endothelial permeability.Conclusion Donor characteristics affect RCC quality parameters and influence the endothelial and immune modulation potential of RCC supernatants in vitro.

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