A comparison of different methods of red blood cell leukoreduction and additive solutions on the accumulation of neutrophil-priming activity during storage

Impact of Different Red Blood Cell Storage Solutions and Conditions on Cell Function and Viability: A Systematic Review

Red blood cell (RBC) storage solutions have evolved significantly over the past decades to optimize the preservation of cell viability and functionality during hypothermic storage. This comprehensive review provides an in-depth analysis of the effects of various storage solutions and conditions on critical RBC parameters during refrigerated preservation. A wide range of solutions, from basic formulations such as phosphate-buffered saline (PBS), to advanced additive solutions (ASs), like AS-7 and phosphate, adenine, glucose, guanosine, saline, and mannitol (PAGGSM), are systematically compared in terms of their ability to maintain key indicators of RBC integrity, including adenosine triphosphate (ATP) levels, morphology, and hemolysis. Optimal RBC storage requires a delicate balance of pH buffering, metabolic support, oxidative damage prevention, and osmotic regulation. While the latest alkaline solutions enable up to 8 weeks of storage, some degree of metabolic and morphological deterioration remains inevitable. The impacts of critical storage conditions, such as the holding temperature, oxygenation, anticoagulants, irradiation, and processing methods, on the accumulation of storage lesions are also thoroughly investigated. Personalized RBC storage solutions, tailored to individual donor characteristics, represent a promising avenue for minimizing storage lesions and enhancing transfusion outcomes. Further research integrating omics profiling with customized preservation media is necessary to maximize post-transfusion RBC survival and functions. The continued optimization of RBC storage practices will not only enhance transfusion efficacy but also enable blood banking to better meet evolving clinical needs.

Production and stability of cultured red blood cells depends on the concentration of cholesterol in culture medium

The production of cultured red blood cells (cRBC) for transfusion purposes requires large scale cultures and downstream processes to purify enucleated cRBC. The membrane composition, and cholesterol content in particular, are important during proliferation of (pro)erythroblasts and for cRBC quality. Therefore, we tested the requirement for cholesterol in the culture medium during expansion and differentiation of erythroid cultures with respect to proliferation, enucleation and purification by filtration. The low cholesterol level (22 µg/dl) in serum free medium was sufficient to expand (pro)erythroblast cultures. Addition of 2.0 or 5.0 mg/dL of free cholesterol at the start of differentiation induction inhibited enucleation compared to the default condition containing 3.3 mg/dl total cholesterol derived from the addition of Omniplasma to serum free medium. Addition of 5.0 mg/dl cholesterol at day 5 of differentiation did not affect the enucleation process but significantly increased recovery of enucleated cRBC following filtration over leukodepletion filters. The addition of cholesterol at day 5 increased the osmotic resistance of cRBC. In conclusion, cholesterol supplementation after the onset of enucleation improved the robustness of cRBC and increased the yield of enucleated cRBC in the purification process.

Isolation methods determine human neutrophil responses after stimulation

Studying neutrophils is challenging due to their limited lifespan, inability to proliferate, and resistance to genetic manipulation. Neutrophils can sense various cues, making them susceptible to activation by blood collection techniques, storage conditions, RBC lysis, and the isolation procedure itself. Here we assessed the impact of the five most used methods for neutrophil isolation on neutrophil yield, purity, activation status and responsiveness. We monitored surface markers, reactive oxygen species production, and DNA release as a surrogate for neutrophil extracellular trap (NET) formation. Our results show that neutrophils isolated by negative immunomagnetic selection and density gradient methods, without RBC lysis, resembled untouched neutrophils in whole blood. They were also less activated and more responsive to milder stimuli in functional assays compared to neutrophils obtained using density gradients requiring RBC lysis. Our study highlights the importance of selecting the appropriate method for studying neutrophils, and underscores the need for standardizing isolation protocols to facilitate neutrophil subset characterization and inter-study comparisons.

Home-based blood transfusion therapy: A systematic review

Home care is a healthcare alternative to hospitalisation. Different types of procedures are performed at home care services, such as home transfusion of blood products. However, home blood transfusion is not fully implemented and there is a great lack of knowledge about it. The aims of this study were thus to assess the safety and effectiveness of home blood transfusions and patient acceptance and satisfaction. A systematic literature review was conducted in the main biomedical databases. We included all studies that covered patients who had received a home blood transfusion, regardless of their baseline diagnosis. The literature search yielded 290 studies, 14 of which were included in this study as they met the predefined criteria. The main patient profile of a home-transfusion recipient was a person with anaemia associated with other diseases. Overall incidence of severe adverse events was 0.05%. No studies evaluated the effectiveness of home versus hospital transfusions. One study showed that 51% of patients would be willing to receive home transfusions. Home blood transfusion appears to be a feasible, safe, and well-accepted procedure. Existing studies are of low quality, however, and this is an important limitation when it comes to drawing definitive benefit-risk conclusions.

The lysophospholipid-binding molecule CD1D is not required for the alloimmunization response to fresh or stored RBCs in mice despite RBC storage driving alterations in lysophospholipids

BACKGROUND

Despite the significant adverse clinical consequences of RBC alloimmunization, our understanding of the signals that induce immune responses to transfused RBCs remains incomplete. Though RBC storage has been shown to enhance alloimmunization in the hen egg lysozyme, ovalbumin, and human Duffy (HOD) RBC alloantigen mouse model, the molecular signals leading to immune activation in this system remain unclear. Given that the nonclassical major histocompatibility complex (MHC) Class I molecule CD1D can bind to multiple different lysophospholipids and direct immune activation, we hypothesized that storage of RBCs increases lysophospholipids known to bind CD1D, and further that recipient CD1D recognition of these altered lipids mediates storage-induced alloimmunization responses.

STUDY DESIGN AND METHODS

We used a mass spectrometry-based approach to analyze the changes in lysophospholipids that are induced during storage of mouse RBCs. CD1D knockout (CD1D-KO) and wild-type (WT) control mice were transfused with stored HOD RBCs to measure the impact of CD1D deficiency on RBC alloimmunization.

RESULTS

RBC storage results in alterations in multiple lysophospholipid species known to bind to CD1D and activate the immune system. Prior to transfusion, CD1D-deficient mice had lower baseline levels of polyclonal immunoglobulin (IgG) relative to WT mice. In response to stored RBC transfusion, CD1D-deficient mice generated similar levels of anti-HOD IgM and anti-HOD IgG.

CONCLUSION

Although storage of RBCs leads to alteration of several lysophospholipids known to be capable of binding CD1D, storage-induced RBC alloimmunization responses are not impacted by recipient CD1D deficiency.

Antimicrobial blue light for decontamination of platelets during storage

Platelet (PLT) storage is currently limited to 5 days in clinics in the United States, in part, due to an increasing risk for microbial contamination over time. In light of well-documented antimicrobial activity of blue light (405-470 nm), we investigated potentials to decontaminate microbes during PLT storage by antimicrobial blue light (aBL). We found that PLTs produced no detectable levels of porphyrins or their derivatives, the chromophores that specifically absorb blue light, in marked contrast to microbes that generated porphyrins abundantly. The difference formed a basis with which aBL selectively inactivated contaminated microbes prior to and during the storage, without incurring any harm to PLTs. In accordance with this, when contamination with representative microbes was simulated in PLT concentrates supplemented with 65% of PLT additive solution in a standard storage bag, all "contaminated" microbes tested were completely inactivated after exposure of the bag to 405 nm aBL at 75 J/cm2 only once. While killing microbes efficiently, this dose of aBL irradiation exerted no adverse effects on the viability, activation or aggregation of PLTs ex vivo and could be used repeatedly during PLT storage. PLT survival in vivo was also unaltered by aBL irradiation after infusion of aBL-irradiated mouse PLTs into mice. The study provides proof-of-concept evidence for a potential of aBL to decontaminate PLTs during storage.

Plasma Transfusion Products and Contamination with Cellular and Associated Pro-Inflammatory Debris

BACKGROUND

Stored plasma products are widely regarded as being functionally acellular, obviating the need for leukoreduction. We tested the hypothesis that donor plasma is contaminated by leukocytes and platelets, which, after frozen storage, would release cellular debris in quantities sufficient to elicit significant pro-inflammatory responses.

STUDY DESIGN

Samples of never-frozen liquid plasma from 2 regional Level I trauma centers were analyzed for leukocyte and platelet contamination. To determine if the cellular contamination and associated debris found in liquid plasma were at levels sufficient to evoke an innate immune response, known quantities of leukocytes were subjected to a freeze-thaw cycle, added to whole blood, and the magnitude of the inflammatory response was determined by induction of interleukin-6.

RESULTS

Units of never-frozen plasma from 2 regional Level I trauma centers located in Alabama and Louisiana contained significant amounts of leukocyte contamination (Louisiana, n = 22; 17.3 ± 4.5 million vs Alabama, n = 22; 11.3 ± 2.2 million) and platelet contamination (Louisiana, n = 21; 0.86 ± 0.20 billion vs Alabama, n = 22; 1.0 ± 0.3 billion). Cellular debris from as few as 1 million leukocytes induced significant increases in interleukin-6 levels (R² = 0.74; p < 0.0001).

CONCLUSIONS

Stored plasma units from trauma center blood banks were highly contaminated with leukocytes and platelets, at levels more than 15-fold higher than sufficient to elicit ex vivo inflammatory responses. In light of paradigm shifts toward the use of more empiric plasma for treatment of hypovolemia, this study suggests that new manufacturing and quality-control processes are needed to eliminate previously unrecognized cellular contamination present in stored plasma products.