Whole Blood Filtration Research Articles

A randomized control trial to compare mortality in recipients of leucoreduced and non-leucoreduced whole blood transfusion in patients with cancer in Uganda

BackgroundMortality benefit of transfusion with leucoreduced whole blood has not been demonstrated in the sub-Saharan Africa (SSA). We compared mortality in patients with cancer transfused with leucoreduced and non-leucoreduced whole blood in a SSA setting.MethodsAn open-label randomized controlled trial was conducted at the Uganda Cancer Institute where participants were randomized in a 1:1 ratio into the leucoreduced and non-leucoreduced whole blood transfusion arms. Leucocyte filtration of whole blood was performed within 72 h of blood collection. Patients aged ≥ 15 years who were prescribed blood transfusion by the primary physicians were eligible for study enrolment. Mortality difference was analyzed using intention-to-treat survival analysis and cox proportional hazard model was used to analyze factors associated with mortality.ResultsThere were 137 participants randomized to the leucoreduced and 140 to the non-leucoreduced arms. Baseline characteristics were similar between the two arms. The median number of blood transfusions received was 1 (IQR, 1–3) unit and 2 (IQR, 1–3) units in the leucoreduced and non-leucoreduced arms respectively, p = 0.07. The 30-day mortality rate in the leucoreduced arm was 4.6% (95% CI, 2.1–10) and was 6.2% (95% CI, 3.2–12.1) in the non-leucoreduced arm (p = 0.57), representing an absolute effect size of only 1.6%. Increasing age (HR = 0.92, 95% CI, 0.86–0.98, p = 0.02) and Eastern Co-operative Oncology Group (ECOG) performance score of 1 (HR = 0.03, 95% CI, 0.00–0.31, p < 0.01) were associated with reduced 30-day mortality.ConclusionsThe study failed to demonstrate mortality difference between cancer patients transfused with leucoreduced and non-leucoreduced whole blood. Although this study does not support nor refute universal leucoreduction to reduce mortality in patients with cancer in SSA, it demonstrates the feasibility of doing transfusion RCTs in Uganda, where a multi-center trial with an appropriate sample size is needed.Trial registrationPan African Clinical Trial Registry, https://pactr.samrc.ac.za/ (PACTR202302787440132). Registered on 06/02/2023.

Bio-Impedance Spectroscopy of Retained Cells Using a Micro-Perforated Sensing Membrane Filtrating Whole Blood Samples under High Flowrate.

Blood filtration using micro-fabricated devices is an interdisciplinary topic of research and innovation driven by clinical applications in cytapheresis, cardiovascular disease monitoring, or liquid biopsy. In this paper, we demonstrate that a micro-perforated membrane can be equipped with sensing microelectrodes for detecting, in situ and in real-time, the capture of cellular material during ex vivo filtration of whole blood under high flow rates. This work describes the fabrication process of the sift and detection microdevice. We demonstrate that reliable electrical signals can be measured in whole blood samples flowing inside a fluidic system at typical flow rates, as large as 11.5 mL/min, hence allowing for large-volume sample processing. The in situ monitoring of the electrical impedance of the microelectrodes is shown to characterize the accumulation of living circulating cells retained by the filtrating membrane, opening interesting applications for monitoring blood filtration processes.

Surface zwitterionization of polypropylene nonwoven fabric by dielectric barrier discharge plasma for efficient leukodepletion

This work reports the development of highly effective leukoreduction filters using dielectric barrier discharge (DBD) plasma applied to polypropylene (PP) nonwoven coated with zwitterionic sulfobetaine methacrylate (SBMA) monomer. The surface modification had no effect on the structural characteristics (pore size, porosity) of the material, but significantly affected its surface chemistry. Mapping IR showed that a homogeneous layer of polySBMA was grown on the surface, resulting in the formation of a superhydrophilic interface that could be immediately wetted by water (the water contact angle reached zero in 0.14 s). This enabled gravity-driven filtration of whole blood. The use of 1, 3, or 5 layers of the optimized grafted membrane obtained after 160 scans in the DBD reactor resulted in 78%, 96.1%, and 99.8% leukocytes removal, respectively, outperforming the commercial alternatives tested. At the same time, more than 90% of erythrocytes were recovered. The large pore size and the wetting behavior of the membrane allow the passage of small cells while limiting cell interactions with the membrane material as the modification reduced leukocyte adhesion by approximately 91%. After 3 washings with PBS, 43% of the attached leukocytes could be detached from the grafted membrane, which is significantly higher than the recovery measured with commercial membranes. Therefore, the membranes are not only efficient as leukoreduction filters, but could also be a viable solution for cell recovery.

Donor sex, pre-donation hemoglobin, and manufacturing affect CD71+ cells in red cell concentrates.

Circulating CD71+ red blood cells (RBCs) have been reported to play an immunomodulatory role in vivo, which may contribute to adverse donor-recipient sex-mismatched transfusion outcomes. However, it is not clear how CD71+ RBC quantity in red cell concentrates (RCCs) is affected by manufacturing methods and donor factors such as donor sex, donor age, pre-donation hemoglobin (Hb), venous Hb (Hbv ) levels, and donation frequency. We determined CD71+ RBCs and Hb levels in whole blood (WB) from healthy donors (42 male/38 female). Using small-scale red cell filtration (RCF) and whole blood filtration (WBF) methods, leukoreduced RCCs were processed from WB samples (n= 6) and the CD71+ RBCs were determined at days 1, 7, and 28. We examined uni- and multivariate associations among CD71+ RBCs, donor factors, and manufacturing method. Male donors had a higher CD71+ RBC concentration than females (p< .001), especially male donors aged 17-50 years with 1 or 2 WB donations over the previous 12 months. Donors with a Hbv above 155 g/L had a higher CD71+ RBC concentration than an Hbv level below 140 g/L (p< .05). There was a positive correlation between pre-donation Hb and CD71+ RBC concentration (Pearson r= 0.41). WBF RCCs had a higher total number of CD71+ RBCs than RCF-produced RCCs on day 1 (p< .05). RCCs have variable numbers of CD71+ RBCs. This makes understanding the impact of donor factors and manufacturing methods on the immunomodulatory effect of CD71+ RBCs critical in exploring donor-recipient sex-mismatched transfusions.

Assessing safety and efficacy of therapeutic plasma exchange in pediatric patients: A single-center experience.

INTRODUCTION:Therapeutic plasma exchange has been widely employed by clinicians for removal of the toxic constituents from plasma by filtration of whole blood and subsequent removal of plasma and reinfusion of cellular components along with a replacement fluid. It has become an accepted therapeutic modality in paediatric patients for numerous indications including but not limited to renal transplant, haemolytic uremic syndrome and Guillain Barre Syndrome. But, data on safety and efficacy are mainly derived from studies in the adult population with very limited data available in the paediatric age group. However, it is technically challenging in children due to their small circulating volume. This study discusses the clinical indications, efficacy, and safety of therapeutic plasma exchange in paediatric population.METHOD:We retrospectively reviewed the data of children (up to 18 years of age) who underwent TPE between January 2017 and March 2019 at our Hospital. Main features of the TPE procedures i.e. frequency of TPE, site of vascular access, type of replacement fluid used, instrument used, plasma volume processed, priming of the circuit, adverse events if any and outcome of the patients were analysed.RESULTS AND CONCLUSION:A total of 114 procedures were performed on these 24 patients. Fifteen patients with Category I indication showed good clinical outcome in terms of attainment of target ABO titre and/or decrease in the donor specific antibody. TPE is an effective therapeutic option in selected paediatric disorders. Our series of data on TPE procedures from paediatric perspective has shown safety and efficacy of the therapy.

Blood manufacturing methods affect red blood cell product characteristics and immunomodulatory activity

AbstractTransfusion of red cell concentrates (RCCs) is associated with increased risk of adverse outcomes that may be affected by different blood manufacturing methods and the presence of extracellular vesicles (EVs). We investigated the effect of different manufacturing methods on hemolysis, residual cells, cell-derived EVs, and immunomodulatory effects on monocyte activity. Thirty-two RCC units produced using whole blood filtration (WBF), red cell filtration (RCF), apheresis-derived (AD), and whole blood–derived (WBD) methods were examined (n = 8 per method). Residual platelet and white blood cells (WBCs) and the concentration, cell of origin, and characterization of EVs in RCC supernatants were assessed in fresh and stored supernatants. Immunomodulatory activity of RCC supernatants was assessed by quantifying monocyte cytokine production capacity in an in vitro transfusion model. RCF units yielded the lowest number of platelet and WBC-derived EVs, whereas the highest number of platelet EVs was in AD (day 5) and in WBD (day 42). The number of small EVs (<200 nm) was greater than large EVs (≥200 nm) in all tested supernatants, and the highest level of small EVs were in AD units. Immunomodulatory activity was mixed, with evidence of both inflammatory and immunosuppressive effects. Monocytes produced more inflammatory interleukin-8 after exposure to fresh WBF or expired WBD supernatants. Exposure to supernatants from AD and WBD RCC suppressed monocyte lipopolysaccharide-induced cytokine production. Manufacturing methods significantly affect RCC unit EV characteristics and are associated with an immunomodulatory effect of RCC supernatants, which may affect the quality and safety of RCCs.

Characteristics of Extracellular Vesicles in Red Blood Concentrates Change with Storage Time and Blood Manufacturing Method

Background: Extracellular vesicles (EVs) in blood products are potential effectors of inflammation and coagulation after transfusion. The aim of this study was to assess the impact of different blood manufacturing methods and duration of hypothermic storage on the EV subpopulations in relation to other in vitro quality parameters of red blood cell concentrate (RCC) products. Methods: RCCs were produced using whole blood filtration (WBF) or red cell filtration (RCF) (n = 12/method), refrigerated for 43 days, and evaluated for EV size profile and concentration, red cell deformability, ATP and 2,3-DPG, hemolysis, and hematological indices. Results: The total number of EVs increased significantly with storage in both methods, and WBF-RCCs contained the higher numbers of EVs compared to RCF-RCCs. The concentration of small EVs was greater in WBF-RCCs versus RCF-RCCs, with difference between the two methods observed on day 43 of storage (p = 0.001). Throughout storage, significant decreases were identified in ATP, 2,3-DPG, and EI_max, while an increase in hemolysis was observed in both RCC products. Conclusion: The dynamic shift in the size and concentration of the EV subpopulations is dependent on the blood manufacturing method and length of storage. Better understanding of the potential clinical implications of these heterogeneous populations of EVs are needed.

Ultrasonic cleaning of polycarbonate sieves for filtration of whole blood from healthy and diabetic subjects

Ultrasonic cleaning of polycarbonate sieves for filtration of whole blood from healthy and diabetic subjects

Quantification of Cell-Free DNA in Red Blood Cell Units in Different Whole Blood Processing Methods.

Background. Whole blood donations in Canada are processed by either the red cell filtration (RCF) or whole blood filtration (WBF) methods, where leukoreduction is potentially delayed in WBF. Fresh WBF red blood cells (RBCs) have been associated with increased in-hospital mortality after transfusion. Cell-free DNA (cfDNA) is released by neutrophils prior to leukoreduction, degraded during RBC storage, and is associated with adverse patient outcomes. We explored cfDNA levels in RBCs prepared by RCF and WBF and different storage durations. Methods. Equal numbers of fresh (stored ≤14 days) and older RBCs were sampled. cfDNA was quantified by spectrophotometry and PicoGreen. Separate regression models determined the association with processing method and storage duration and their interaction on cfDNA. Results. cfDNA in 120 RBC units (73 RCF, 47 WBF) were measured. Using PicoGreen, WBF units overall had higher cfDNA than RCF units (p = 0.0010); fresh WBF units had higher cfDNA than fresh RCF units (p = 0.0093). Using spectrophotometry, fresh RBC units overall had higher cfDNA than older units (p = 0.0031); fresh WBF RBCs had higher cfDNA than older RCF RBCs (p = 0.024). Conclusion. Higher cfDNA in fresh WBF was observed compared to older RCF blood. Further study is required for association with patient outcomes.

Assessing the influence of component processing and donor characteristics on quality of red cell concentrates using quality control data.

Quality control (QC) data collected by blood services are used to monitor production and to ensure compliance with regulatory standards. We demonstrate how analysis of quality control data can be used to highlight the sources of variability within red cell concentrates (RCCs). We merged Canadian Blood Services QC data with manufacturing and donor records for 28 227 RCC between June 2011 and October 2014. Units were categorized based on processing method, bag manufacturer, donor age and donor sex, then assessed based on product characteristics: haemolysis and haemoglobin levels, unit volume, leucocyte count and haematocrit. Buffy-coat method (top/bottom)-processed units exhibited lower haemolysis than units processed using the whole-blood filtration method (top/top). Units from female donors exhibited lower haemolysis than male donations. Processing method influenced unit volume and the ratio of additive solution to residual plasma. Stored red blood cell characteristics are influenced by prestorage processing and donor factors. Understanding the relationship between processing, donors and RCC quality will help blood services to ensure the safety of transfused products.

Determining the Volume of Additive Solution and Residual Plasma in Whole Blood Filtered and Buffy Coat Processed Red Cell Concentrates

Background: Residual plasma in transfused red cell concentrates (RCCs) has been associated with adverse transfusion outcomes. Despite this, there is no consensus on the standard procedure for measuring residual plasma volume. Methods: The volumes of residual plasma and additive solution were measured in RCCs processed using two separation methods: whole blood filtration (WBF) and buffy coat (BC)/RCC filtration. The concentration of mannitol and albumin in RCC components was measured using colorimetric assays. Mannitol concentration was used to calculate additive solution volume. Residual plasma volume was calculated using two methods. Results: Calculated RCC supernatant volumes were much lower in BC-processed components compared to WBF-processed components (BC = 97 ± 6 ml, WBF = 109 ± 4 ml; p < 0.05). Calculated additive solution volumes were greater in WBF- than in BC-processed components (BC = 81 ± 4 ml, WBF = 105 ± 2 ml; p < 0.05). Absolute residual plasma volume varied significantly based on the calculation method used. Conclusion: Disparity between plasma volume calculation methods was observed. Efforts should be made to standardize residual plasma volume measurement methods in order to accurately assess the impact of residual plasma on transfusion outcomes.

Buffy coat (top/bottom)- and whole-blood filtration (top/top)-produced red cell concentrates differ in size of extracellular vesicles.

The influence that blood component separation methods have on changes to the red blood cell membrane during storage is not well understood. In Canada, red cell concentrates (RCCs) are produced using the buffy coat (BC, top/bottom) and the whole-blood filtration (WBF, top/top) methods, and this study aimed at comparing their influence on the characteristics of the extracellular vesicles (EV) which accumulated in the respective products during storage. Using flow cytometry, dynamic light scattering and mass spectrometry, we assessed RCC EVs for concentration, size, lipid composition and correlation with supernatant haemoglobin (Hb). Accumulation of RBC EVs (CD235a(+) ) with storage time was similar in WBF and BC RCCs. The size of the EVs changed from <100 nm at d5 to near 200 nm by d42, with the EVs from WBF being smaller (P < 0·001) than BC RCCs at all storage times. The amount of EV-bound Hb in the WBF and BC units was similar (about 10% of total supernatant Hb). WBF EVs and BC EVs displayed similar lipid composition. Haemolysis and EVs increase in BC and WBF RCCs during storage. Differences in the size characteristics of the EVs in WBF and BC RCCs suggest that non-RBC EVs are more prevalent in WBF products. Understanding the impact that manufacturing has on the characteristics of the different populations of EVs in RCCs will aid quality improvement efforts.

Transitory interruption of recommended storage conditions does not cause significant changes in in vitro parameters of leucocyte-depleted red blood cells

Conventional quality control studies of the shelf life of RBC units do not consider cold chain interruptions that occur during cross-matching or between the release of RBCs from the blood bank and their return from the ward. These interruptions may, however, lead to a considerable loss of quality. On the other hand, differences in the quality of RBCs may derive from the different manufacturing processes employed in various blood centres. One day after the expiry date of the RBC unit, we analysed complete blood count, blood gas, potassium, LDH, hydroxybutyrate dehydrogenase, glucose, lactate, total and free haemoglobin (Hb) and ATP and compared the results with regard to the frequency of storage interruptions and to two manufacturers of these RBCs. We could not find any correlations between the frequency of interruptions (0-11) and these parameters in any of the data sets. However, we found significant differences when comparing the two suppliers. RBCs of manufacturer A ('A', inline filtration of whole blood) contained 25% more Hb than those of manufacturer B ('B', inline filtration after buffy coat reduction). Sixteen percentage of 'A'-RBC, but none of 'B'-RBC, exceeded a haemolysis of 0.8%. Transitory interruptions of cold chain do not measurably impair the quality of RBCs. The effect on storage of RBCs in the blood bank is not as significant a factor as the differences that exist between RBC manufacturing procedures.

Response to Zimmermann et al

Dear Editor, We appreciate the opportunity to respond to Zimmermann et al. They refer to publications by Vamvakas [1] and Heuft et al. [2]. Both base their conclusion on mathematical models. Vamvakas presents calculations for additional transfusion transmitted infections (TTI) contracted through platelet transfusions in the United States (US) if pooled platelet concentrate (PPC) would completely replace singledonor apheresis platelet concentrates (APC)[1]. These calculations are based on assumptions which do not all apply for Europe. The calculation is based on the risk of TTI in the US today (1 per 2 135 000 donations for HIV, 1 per 1 935 000 for HCV and 1 per 280 000 for HBV [1]). For the German Red Cross Blood Donor Services, the residual risk for TTI is substantially lower (data 1997–2005): 1 per 4 300 000 donations for HIV, 1 per 10 880 000 for HCV and 1 per 360 000 for HBV [3]. This analysis does not account the effect of anti-HBc testing, which became mandatory in Germany since 2006 and will most likely reduce the risk for HBV. The ‘worst-case scenario’ of Vamvakas who carefully confines the conclusions to the United States assumes that a PPC contains platelets from six whole blood (WB) donations [1]. In many European countries, PPC is pooled from five or four donations. The risk calculation is substantially different if assuming six or four donor exposures per PPC [1]. A significant proportion of APC represents split products so that an infected donor can infect two or even three recipients by one donation and in addition further recipients by subsequent donations during the ‘window period’ because of the potentially short interval of APC donations [4]. A model on GBV-C virus infections takes into account that pooling of a GBV-C RNA positive buffy coat (BC) with a BC containing a GBV-C neutralizing antibody could lead to a non-infectious PPC. A careful sensitivity analysis demonstrates that the number of theoretical GBV-C transmissions depends on the assumed frequency of neutralizing antibodies in the donor population [2]. Many assumptions affect the results of mathematical models and delimit their conclusions [4]. Zimmermann et al. argue that the preparation of PPC affects the quality of red blood cell concentrates (RCC) resulting ‘in a remarkable proportion of underfilled RCC’. The binding German Haemotherapy Guidelines [5] and the ‘Guide to the preparation, use and quality assurance of blood components’ [6] stipulate that at least 95% of the leucocyte-depleted RCC must contain ‡ 40g haemoglobin ⁄unit. The mean haemoglobin of RCC produced by our Blood Service using RCC filtration after BC-removal is 56AE4 g, and only 0AE2% of RCC had haemoglobin content below 40 g ⁄unit, and there is no difference when comparing haemoglobin content in RCC produced from donations without or with concomitant preparation of a PPC. For our Blood Service, we can decline that preparation of PPC by the BC method results in a remarkable proportion of underfilled RCC – and this applies also to other blood services obliged to meet regulatory requirements. Zimmermann et al. refer to the loss of 2,3-DPG during overnight storage at 22 C [7]. Several aspects need to be considered in interpretation of this surrogate parameter: Rapid cooling slowed the loss of 2,3-DPG levels but 2,3DPG levels were undetectable by day 21 irrespective of the initial storage temperature [7]. Wilsher et al. [7] compared processing within 8h versus storage for 24 h at 22 C. In practice, the actual interval between donation and start of processing in most institutions is shorter than 24 h even if overnight storage at 22 C is involved. It has been shown that 2,3-DPG levels return to near normal levels after transfusion [8]. The clinical significance of the observed difference needs to be studied further. Overnight storage at 22 C can increase the efficiency of separation of platelets from WB donations and can reduce bacterial contamination. Zimmermann et al. argue that the processing method affects the levels of platelet-derived cytokines in RCC [9]. It is important to take into account all details of the processing. A high concentration of platelet-derived cytokines was measured in PC prepared with the dock-in Sepacell RBC filter or with platelet-saving WB filters before removing plasma or platelet-rich plasma. In this study, the plasmareduced RCC (still containing platelets) were held overnight at 4 C. Neither a storage at 4 C nor a storage overnight after removal of plasma nor the use of platelet-saving WB filters can be considered as standard procedure for PPC Vox Sanguinis (2010)

Preventing Platelet-Derived Microparticle Formation—and Possible Side Effects—With Prestorage Leukofiltration of Whole Blood

Platelet-derived microparticles (PDMPs) probably function in hemostasis, thrombosis, inflammation, and transfusion-related immunomodulation. To compare PDMP levels of leukocyte-filtered and unfiltered whole blood during storage. Ten whole blood donations were collected and processed. Half of each collection was filtered, half remained unfiltered, and both halves were measured for red cell, white cell, and platelet (PLT) content before storage. Samples were drawn on days 0, 1, 2, 3, 5, 7, 14, 21, 28, and 35 and analyzed by flow cytometry. Leukocyte filtration lowered prestorage PDMP and PLT counts by an average of 72% and 99%, respectively. Prestorage PDMP counts were 123 +/- 51/microL in unfiltered whole blood supernatant versus 34 +/- 18/microL after filtration. Prestorage PLT counts were 190 +/- 49/microL in unfiltered whole blood supernatant versus 2 +/- 4/microL after filtration. Moreover, PDMP and PLT counts in filtered whole blood remained low throughout storage, typically below 100/microL. In contrast, unfiltered whole blood PDMP- and PLT-gated events increased approximately 2 log during storage, with the peak number of PLT-gated events tending to coincide with the peak number of PDMP-gated events (4 donors) or to come after the peak number of PDMP-gated events (6 donors). Leukocyte filtration of whole blood lowers prestorage PDMP and PLT counts. Platelet-derived microparticle and PLT counts remain low throughout 35 days of storage. In contrast, PDMP- and PLT-gated events increase significantly in unfiltered whole blood. The nature of PLT-gated events in stored blood warrants further investigation.

Plasma and cryoprecipitate manufactured from whole blood held overnight at room temperature meet quality standards

With buffy coat (BC) processing of whole blood (WB) donations, the preparation of plasma occurs within 24 hours rather than 8 hours of collection. The effect of this change on coagulation factor function in plasma and cryoprecipitate was evaluated during the validation of this production method and with routine production. Plasma frozen after an overnight hold of WB was prepared via BC or whole blood filtration (WBF) methods and quality control (QC) variables were measured. Additionally, plasma prepared with the BC method was compared to plasma produced using the platelet-rich plasma (PRP) method with an extended plasma factor analysis. Selected plasma factor levels were also measured in both cryoprecipitate and cryosupernatant plasma prepared using the WBF method from plasma frozen on the day of collection or after an overnight hold of WB. When comparing BC plasma to PRP plasma, coagulation factors (F)II, VII, VIII, IX, X, and XI had somewhat lower levels, and fibrinogen and antithrombin levels were elevated. As expected the most sensitive to the prolongation of production time was FVIII with 72 and 78% of the activity of PRP plasma and cryoprecipitate, respectively. However, both still met QC standards. Similarly, products made in routine production show acceptable levels of FVIII. Plasma and cryoprecipitate products, prepared using methods in which the plasma is frozen close to 24 hours after collection, meet current quality standards. The longer WB storage time has been implemented into general use in Canada.

Storage of whole blood overnight in different blood bags preceding preparation of blood components: in vitro effects on red blood cells.

Routines for the storage of whole blood (WB) overnight for the preparation of blood components on the following day are of increasing interest primarily for logistic reasons. The present study focuses on in vitro effects during storage for 6 weeks on red blood cells (RBC) prepared in different blood containers after being held overnight. Five different blood collection systems were used with either inline leucocyte reduction red cell filters for the preparation of RBC, buffy coat (BC) and plasma or WB filters for the preparation of RBC and plasma. A new container with an integrated WB filter removing leucocytes but not platelets was also included for the preparation of leucocyte-reduced RBC, BC and plasma units. Standard CPD solution (63 or 70 mL) and SAG-M solution (100 or 110 mL) were used for the collection of either 450 or 500 mL blood. All WB units were stored at room temperature, either overnight for 18-24 hours (test groups, n=104) or for up to 8 hours (reference groups, n=20). In addition, five test units were stored overnight under refrigeration. In test groups (overnight storage at room temperature) we found significantly lower levels of extracellular potassium, 2,3-DPG and pH (up to day 28). During storage, higher levels of ATP (Terumo, CaridianBCT until day 35, Fresenius until day 14, Fenwal throughout storage) were seen in test groups than in reference groups. When WB was stored overnight at 2-6 degrees C before WB filtration, the levels of ATP and haemolysis were higher than in the corresponding reference. Significant differences in in vitro parameters were observed between RBC prepared within 8 hours and 18-24 hours after blood collection. The results were consistent irrespective of the blood container used. New alkaline solutions may decrease the differences.

Clinical Effects of Chronic Red Blood Cell Exchange and Different Types of Red Cell Concentrates in Patients with Sickle Cell Disease

For patients with severe SCD not eligible for hydroxyurea, two major therapeutic options are currently available: blood transfusion, and bone marrow transplantation. Either urgent or chronic red blood cell transfusion therapy, is widely used in the management of SCD but determines a progressive increase of ferritin level and is also limited by the development of antibodies to red cell antigens. The introduction of chronic red blood cell exchange and prestorage filtration to remove leucocytes and the use of techniques for multicomponent donation could be a good solutions. Thus, the aims of our studies were to evaluate the clinical effects of the different blood components in terms of annual transfusion needs and the intervals between transfusion, moreover we evaluated the efficacy of chronic red blood cell exchange (manual or automatic with cell separator) in preventing SCD complications and limiting iron overload. In our center we follow 78 patients affected by Sickle Cell Disease. We selected 36 patients occasionally treated with urgent red blood cell exchange because they had less than 2 complications/Year, and 42 patients regularly treated with chronic red blood cell exchange because they had more than 2 complications/Year with Hospital Admission. Moreover among these we selected 10 patients for fulfilling the criteria of continuous treatment at the Centre for at least 48 months with no interruptions, even sporadic and absolute transfusion dependency. All 10 patients were evaluated for a period of 4 years, during which two different systems of producing RCC were used. In the second two the patients were transfused with RCC obtained from filtering whole blood prestorage or with RCC from apheresis filtered prestorage. These products differed from those used in the preceding two years, during which the leucodepletion was obtained by bed-side filtration For all the patients we performed 782 automatic red blood cell exchanges and 4421 units of RCC were transfused. The exchange procedures were extremely well-tolerated by the patients and adverse effects were limited to symptoms of hypocalcaemia during automatic red blood cell exchange with cell separator. After every red blood cell exchange we obtained HbS level < 30%. The10 patients selected received respectively a mean of 6.9 and 6.1 units of RBCs exchanged per automatic procedure, in the first two years and in the second two years. Alloantibody developed in 14 patients but only 2 clinically significant and about the observed frequency of transfusion reactions it was very low. All patients treated with chronic red blood cell exchange had an improvement of the quality of life with a reduced number of complications/year (<2/year) and good compliance and moreover patients had limited iron overload making chelating therapy easier. In conclusion this study was focused on the most suitable characteristics of blood components for use in sickle cell disease patients and the choice of systematically adopting prestorage filtration of whole blood, enabled us to have RCC with a higher Hb concentration than standard. Moreover chronic manual or automatic red blood cell exchange as an alternative approach to simple long-term RBC transfusions give many advantages by being more rapid and tolerable as well as clinically safe and effective and minimize the development of iron overload especially when procedure was carried out with an automatic apparatus. To note that the clinical advantages for patients derived from good selection of the donor and good practices in the production of the blood components

Neutrophil priming, caused by cell membranes and microvesicles in packed red blood cell units, is abrogated by leukocyte depletion at collection

Background and objects Lipids with platelet activating factor (PAF)-like activity in supernatant of packed red blood cells (PRBC) cause priming of the neutrophil respiratory burst. This effect increases with length of storage. Washing of PRBC has been considered as a means to eliminate this effect; however, the role of the cellular component was not evaluated independently of the supernatant. The source of the inflammatory lipids of the supernatant is likely to be cell membranes altered during ageing in storage and therefore, washing will not eliminate neutrophil priming caused by transfusion of aged PRBC units. The ability of washed PRBC to prime mononuclear cells for another known effect of PAF, the production of IL-8, and the probability that this lipid activity is present on microparticles in PRBC supernatant were also investigated. Materials and methods At collection 10 units of whole blood were split into two equal aliquots one filtered and one unfiltered. PRBC were prepared and stored at 4 °C in CPD-AS5. Each week, fresh neutrophils were incubated with samples of washed PRBC and fixed. Change in CD11b, a marker known to increase on the surface of primed neutrophils, was determined by flow cytometry. To determine whether neutrophil priming ability of PRBC supernatant is contained on microvesicles, centrifuged and uncentrifuged supernatant samples were incubated with fresh neutrophils and change in CD11b expression was determined. Plasma IL-8 levels were also measured after exposure of monocytes from fresh whole blood to filtered and unfiltered washed PRBC with and without the addition of fMLP. Results Washed PRBC caused a 50–116% increase in CD11b neutrophil surface expression over baseline expression. Filtration of whole blood at collection reduced this CD11b up-regulation by 25–34%. Reduction of priming ability by filtration began on the day of collection and persisted for the storage life of the units. Centrifugation resulted in a reduction of CD11b up-regulation of 11–28% compared with unspun supernatant. Incubation of unfiltered PRBC resulted in priming of mononuclear leukocytes for IL-8 production with a 73–109% increase over baseline, but no increase over baseline was seen for incubation with filtered blood. Conclusion Washing does not eliminate the ability of PRBC units to prime neutrophils and mononuclear cells, because the cellular component of PRBC, in addition to the supernatant, induces priming. Leukodepletion filters significantly reduce these effects compared with unfiltered PRBC. The in vitro beneficial effect of filtration lasts for the shelf life of 42 day units. The ability of PRBC supernatant to prime neutrophils is present on microvesicles.

Leukodepletion filters reduce Leishmania in blood products when used at collection or at the bedside

Leishmania is an intracellular parasite of monocytes transmissible by transfusion. The feasibility of reducing Leishmania with leukodepletion filters was studied. At collection, infected blood contains the amastigote form of Leishmania within monocytes. Amastigotes cause the rupture of monocytes releasing free amastigotes that convert to promastigotes, which exist extracellularly at blood storage temperatures. Leukodepletion filters were tested at various time points in this process. Blood products were infected with Leishmania organisms and then filtered with whole-blood filters at collection, with bedside filters after storage, and to determine whether free promastigotes could be eliminated. Filtration at collection reduced Leishmania by 3 to 4 log or to the level of detection. Filtration of infected red cells after 2 weeks of storage showed a reduction of Leishmania by 4 log. Filtration resulted in a 6- to 8-log reduction in promastigotes either in the presence or in the absence of white cells within the filter. Filtration at the time of collection and after storage of Leishmania-infected blood resulted in a substantial reduction of free and intracellular organisms. There is currently no donor screen for Leishmania. Until adequate testing is developed, the use of leukodepletion filters could add to the safety of the blood supply.