Prestorage Leukodepletion Research Articles

Prestorage Inline Leukodepletion of Buffy Coat-depleted Packed Red Blood Cells: Comparative Analysis of White Blood Cell Count and Interleukin-8 between Leukodepleted and Nonleukodepleted Packed Red Blood Cells

Background and Objectives: We aimed to analyze the impact of prestorage Inline leukodepletion and storage time on interleukin 8 (IL-8) levels in stored buffy coat-depleted packed red blood cell (PRBC) units in the Kashmiri population setting. Methods: A total of 50 donors of Kashmiri origin from North India equally and randomly distributed between Leukodepleted (LD) and non-LD (NLD) arms were recruited in this study. Leukodepletion of PRBCs units was performed using 3rd Generation integrated LD filters and the residual white blood cell (WBC) count was enumerated by FACS using fluorochrome-tagged CD45+ antibodies and IL-8 levels measured by ELISA. Results: In contrast to NLD arm, leukodepletion in the LD arm significantly reduced total leukocyte count (TLC) from pre-LD TLC of 2.25 ± 0.47 × 109/PRBC unit to post LD cell count of 2.40 ± 0.65 × 106/PRBC unit, P = 0.001, i.e., 3 log reduction, P = 0.0001. Contrary to the LD arm, a significant difference in IL-8 levels in NLD arm was observed with 27.15 ± 30.32 pg/mL on day 0, 45.15 ± 36.15 pg/mL on day 14, and on day 28, 37.98 ± 33.05 pg/mL. Furthermore, significant variance (LD vs. NLD) in IL-8 levels was observed at day 0, 14th, and 28th day of storage, with maximum variance observed on day 14th Fstat = 21.46, P = 0.00, depicting prestorage LD have a significant role in suppressing the IL-8 levels in LD stored PRBC units while as in NLD PRBC units with time IL-8 accumulated as its cell source (WBCs) was intact. Conclusion: Inline prestorage leukodepletion by 3rd generation LD filters was uniformly effective in reducing the residual WBC count to desired levels of <5 × 106/unit of PRBC. The significant decrease in TLC and resultant far less accumulation of cytokine (IL-8) in prestorage LD PRBC units of Kashmiri origin, as observed in this study, would be translated into clinical benefits associated with transfusion of LD-PRBC units.

Guideline development for prevention of transfusion-associated graft-versus-host disease: reduction of indications for irradiated blood components after prestorage leukodepletion of blood components.

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare, commonly fatal complication of transfusion preventable by irradiation of blood units. The revision of the Dutch transfusion guideline addressed the question whether irradiation is still necessary if blood components are prestorage leukodepleted. We searched for published cases of TA-GVHD following transfusion of prestorage leukodepleted blood and through contacting haemovigilance systems. Six presumed cases were found, dating from 1998 to 2013. Four out of six patients had received one or more non-irradiated units despite recognised indications for irradiated blood components. In the countries providing information, over 50 million prestorage leukodepleted, non-irradiated, non-pathogen-reduced cellular components were transfused in a 10-year period. Potential benefits of lifting indications for irradiation were considered. These include reduced irradiation costs (€ 1.5 million annually in the Netherlands) and less donor exposure for neonates. Findings were presented in an invitational expert meeting. Recommendations linked to human leukocyte antigen similarity between donor and recipient or intra-uterine transfusion were left unchanged. Indications linked to long-lasting deep T-cell suppression were defined with durations of 6 or 12 months after end of treatment (e.g. autologous or allogeneic stem cell transplantation). Need for continued alertness to TA-GVHD and haemovigilance reporting of erroneous non-irradiated transfusions was emphasised.

A Preliminary Analysis of the Incidence of Transfusion-Related Acute Lung Injury (TRALI) in a Sheep Model Following Transfusion with the Supernatant from Leukodepleted Red Cell Units

IntroductionDespite the introduction of risk reduction strategies, transfusion-related acute lung injury (TRALI) continues to be a significant cause of morbidity and mortality. TRALI development may be associated with the transfusion of anti-leucocyte antibodies or biological response modifiers (BRMs). Our group has previously developed a model in which the development of TRALI in lipopolysaccharide (LPS) treated sheep was precipitated by the transfusion of pooled supernatant from date-of-expiry (day (d) 42) packed red blood cell (PRBC) units. This work pre-dated the introduction of pre-storage leukodepletion of PRBCs in Australia, therefore we investigated whether TRALI would still develop in LPS-treated sheep transfused with supernatant from d42 leukodepleted PRBCs.MethodsOn either d2 (n=75 units) or d42 (n=113 units) of storage, leukodepleted PRBCs underwent dual centrifugation to obtain acellular supernatants. Two supernatant pools (d2 and d42) were then prepared by pooling and heat-treating (56°C for 30min) the supernatants. Levels of potential BRMs in the PRBC supernatant pools were characterised using cytometric bead array and ELISA. Instrumented sheep (n=14) were infused with LPS then transfused (10% v/v) with either d2 (n=7) or d42 (n=7) pooled PRBC supernatant. Two hours later sheep were euthanized and post-mortem lung samples were collected. Physiological data were recorded continuously and then averaged in 30 minute blocks for these preliminary analyses. Blood and broncoalveolar lavage (BAL) fluid samples were collected at specific intervals. Blood samples were used for arterial blood gas analyses, coagulation tests (ROTEM), platelet function tests (MultiPlate) and ELISAs. TRALI was defined by hypoxemia (PaO2/FiO2 < 300 on arterial blood gas) and histological evidence of pulmonary edema (by two blinded histopathological assessments of hematoxylin and eosin stained lung sections). Data were compared by group (sheep transfused with d2 PRBC supernatant vs. d42 PRBC supernatant) and by outcome (sheep who developed TRALI vs. those who did not) with either t-tests or 2-way ANOVAs as appropriate.Results and DiscussionStorage duration of leukodepleted PRBC was associated with increased levels of the potential BRMs 5-HETE, 12-HETE, 15-HETE and IL-8, but not soluble CD40 ligand. Only 3 sheep developed TRALI: one transfused with d2 leukodepleted PRBC supernatant and two transfused with d42 leukodepleted PRBC supernatant corresponding to an incidence of 14% and 29% respectively. This indicated a reduced incidence of TRALI in the sheep model compared to previous data using supernatant from d42 non-leukodepleted PRBC which resulted in an incidence of 75% (Tung et al. Vox Sanguinis. 2011). Preliminary analyses of the physiological data revealed a number of differences. Heart rate (P<0.001), blood pressure (P=0.003), pulmonary artery pressure (P<0.001), cardiac output (P<0.001) and PaO2/FiO2 (P<0.001) were different between sheep transfused with either d2 or d42 PRBC supernatant. Heart rate (P<0.001), pulmonary artery pressure (P<0.001), pulse oximeter oxygen saturation (P=0.003), cardiac output (P<0.001) and PaO2/FiO2 (P<0.001) were different between sheep that developed TRALI and sheep that did not. However, given the complexity of these data, further analyses using mixed effects modelling are required to better understand these differences. Sheep transfused with d42 PRBC supernatant had reduced IL-1β lung gene expression and reduced ADP-induced platelet aggregation (both total and area under curve) compared to sheep transfused with d2 PRBC supernatant (P=0.047, 0.012 and 0.028 respectively). In addition, sheep that developed TRALI had worse lung histology scores as well as reduced collagen-induced platelet aggregation (both total and area under curve) compared to sheep who did not develop TRALI (P=0.024, 0.049 and 0.018 respectively).ConclusionsComparison of these results to previously published data from the sheep model is suggestive that pre-storage leukodepletion of PRBCs is associated with a reduced incidence of TRALI. Unsurprisingly, the development of TRALI was associated with worsened respiratory function (oxygen saturation and PaO2/FiO2) and lung histology scores, while changes in hemodynamics and platelet function were also observed. DisclosuresFraser:Fisher and Paykel Healthcare: Consultancy, Other: Provision of equipment for research use, Research Funding; De Motu Cordis: Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

A Comparative Study of the Effect of Leukoreduction and Pre-storage Leukodepletion on Red Blood Cells during Storage.

Blood transfusion is a fundamental therapy in numerous pathological conditions. Regrettably, many clinical reports describe adverse transfusion's drawbacks due to red blood cells alterations during storage. Thus, the possibility for a blood bank to ameliorate the quality of the erythrocyte concentrates units is crucial to improve clinical results and reduce transfusion adverse occurrences. Leukodepletion is a pre-storage treatment recognized to better preserve the quality of red blood cells with respect to leukoreduction. Aim of this work is to unravel the biochemical and biophysical basis that sustain the good clinical outcomes associated to the use of leukodepleted erythrocytes units. Erythrocytes concentrates were prepared as leukoreduced (n = 8) and pre-storage leukodepleted (n = 8) and then studied during 6 weeks in blood bank conditions. Overall, the data indicate that leukodepletion not only provide red blood cells with an appropriate amount of nutrients for a longer time but also selects red blood cells characterized by a more resilient plasma membrane fit to prolong their viability. We believe these results will stimulate new ideas to further optimize the current storage protocols.

Introduction of universal prestorage leukodepletion of blood components, and outcomes in transfused cardiac surgery patients

To assess whether introduction of universal leukodepletion (ULD) of red blood cells (RBCs) for transfusion was associated with improvements in cardiac surgery patient outcomes. Retrospective study (2005-2010) conducted at 6 institutions. Associations between leukodepletion and outcomes of mortality, infection, and acute kidney injury (AKI) were modeled by logistic regression, and intensive care unit length of stay (LOS) in survivors was explored using linear regression. To examine trends over time, odds ratios (ORs) for outcomes of transfused were compared with nontransfused patients, including a comparison with nontransfused patients who were selected based on propensity score for RBC transfusion. We studied 14,980 patients, of whom 8857 (59%) had surgery pre-ULD. Transfusions of RBCs were made in 3799 (43%) pre-ULD, and 2525 (41%) post-ULD. Administration of exclusively leukodepleted, versus exclusively nonleukodepleted, RBCs was associated with lower incidence of AKI (adjusted OR 0.80, 95% confidence interval [CI] 0.65-0.98, P = .035), but no difference in mortality or infection. For post-ULD patients, no difference was found in mortality (OR 0.96, 95% CI 0.76-1.22, P = .76) or infection (OR 0.91, 95% CI 0.79-1.03, P = .161); however, AKI was reduced (OR 0.79 95% CI 0.68-0.92, P = .003). However, ORs for post-ULD outcomes were not significantly different in nontransfused, versus transfused, patients. Furthermore, those who received exclusively nonleukodepleted RBCs were more likely to have surgery post-ULD. Universal leukodepletion was not associated with reduced mortality or infection in transfused cardiac surgery patients. An association was found between ULD and reduced AKI; however, this reduction was not significantly different from that seen in nontransfused patients, and other changes in care most likely explain such changes in renal outcomes.

Pathogen inactivation of whole blood and red cell components: An overview of concept, design, developments, criteria of acceptability and storage lesion

Multilayer preventative strategies have been instituted to enhance transfusion safety for patients in need of critical blood components. Presently blood safety is at its highest levels, with the implementation of precautionary/preventative measures against vCJD, bacterial and viral contamination of the blood supply. The implementation of these strategies together with advances in automation and computerization led to significant improvements in standardisation for transfusion practices. These include validation, verification, adherence to GLP and GMP and other regulatory requirements. In most European countries, universal prestorage leukodepletion is routine practice. In France proactive pathogen inactivation treatments [PITs] have been implemented emphasizing patient safety. This at least conceptually reduces the risk of transfusing viable WBCs, emerging bacteria and viruses, all with potential transfusion complications. In the UK, prion removal filters for red cell products are used selectively for special groups of patients. Some research establishments are exploring the potential impact of pathogen inactivation of whole blood or red cell components, using the new generation of S-303 PIT and the prion removal filters in combination. It needs to be determined whether such a combined strategy, applied synergistically, enhances red cell transfusion safety without compromising the overall criteria of acceptability. It is necessary to critically examine the impact of a new generation of PIT technologies, which may exacerbate the red cell storage lesion and cause the development of undesirable antibodies in the recipient. The development of innovative laboratory tools is vital to study impacts of these measures on the quality of stored blood and their clinical outcome. The ultimate aim of red cell transfusion is to provide oxygen enriched red blood cells to the microcirculations and tissues. Definitive studies are needed to establish the potential unforeseen negative long term toxicity, overall efficacy/quality and the clinical outcome of treated stored blood.

Impact of alloantigens and storage-associated factors on stimulated cytokine response in an in vitro model of blood transfusion.

Transfusion of blood may contribute to immunosuppression in major surgery. The authors assessed the impact of alloantigens and storage on function of peripheral blood mononuclear cells cultured in their physiologic environment. Blood units (whole blood, packed erythrocytes) were prepared with or without prestorage leukodepletion and stored for 24-26 days. Blood samples were coincubated with allogeneic fresh blood, autologous, or allogeneic stored blood. Endotoxin-stimulated release of tumor necrosis factor-alpha (TNF-alpha) and interleukin 10 (IL-10) was measured after 24 h of culture by enzyme-linked immunosorbent assay. Coincubation with equal amounts of allogeneic fresh blood showed almost no influence on TNF-alpha (-12%, not significant) and IL-10 (+11%, not significant) release. Stored allogeneic whole blood resulted in a significant TNF-alpha depression (-61%) and IL-10 induction (+221%). These effects were diminished but not prevented by prestorage leukodepletion (TNF-alpha -42%, IL-10 +110%) and required the presence of soluble factors (TNF-alpha suppression) and cellular components (IL-10 induction). TNF-alpha decrease and IL-10 increase were in the same order of magnitude (-40%, +134% with, -65%, +314% without leukodepletion) after coincubation with autologous blood. In contrast, allogeneic erythrocytes had only little effects (TNF-alpha -6%, IL-10 +36%) even at this high transfusion equivalent. These data suggest that banked whole blood has an immunosuppressive effect that is largely attributable to storage-dependent factors. These factors are partially removed by prestorage leukodepletion, while the contribution of alloantigens is of minor significance. Immunosuppressive effects are least apparent with leukodepleted erythrocytes, suggesting that the presence of plasma during storage is required for the immunosuppressive effect to develop.

Plasma from Aged Stored Red Blood Cells Delays Neutrophil Apoptosis and Primes for Cytotoxicity: Abrogation by Poststorage Washing but Not Prestorage Leukoreduction

Blood transfusion-particularly that of older stored red blood cells (RBCs)--is an independent risk factor for postinjury multiple organ failure. Immunomodulatory effects of RBC transfusion include neutrophil (PMN) priming for cytotoxicity, an effect exacerbated by longer RBC storage times. We have found that delayed PMN apoptosis in trauma patients is provoked by transfusion, independent of injury severity. We hypothesized that aged stored RBCs delay PMN apoptosis, but that prestorage leukodepletion or poststorage washing could abrogate the effect. Healthy volunteers each donated 1 unit of blood. One half was leukodepleted, and RBC units were processed in the usual fashion and stored at 4 degrees C. Aliquots were removed on days 1, 14, 21, and 42 and the plasma fraction isolated. Selected aliquots were washed with normal saline before plasma isolation. PMNs harvested from healthy controls were incubated (5% CO2, 37 degrees C) with unmodified, leukoreduced, or washed RBC plasma (20% plasma/80% RPMI 1640), and apoptosis assessed by morphology after 24 hours. Apoptotic index (apoptotic PMNs/total PMNs) was compared. PMN priming for superoxide release was also assessed after plasma exposure. PMN apoptosis was delayed by RBCs stored for 21 or 42 days. Prestorage leukodepletion did not alter the effect. However, washing 42-day-old RBCs abrogated the effect. PMN priming for superoxide was provoked by stored packed RBCs in an identical pattern to delayed apoptosis. Plasma from stored RBCs-even if leukoreduced-delays apoptosis and primes PMNs. The effect becomes evident at 21 days and worsens through product outdate (42 days), but may be prevented by poststorage washing. Inflammatory agents contaminating stored blood likely mediate the effect. Modification of transfusion practices (e.g., giving fresher or washed RBCs or blood substitutes) may attenuate adverse immunomodulatory effects of transfusion in trauma patients.

Evaluation of Proinflammatory Cytokines in Prestorage Leukodepleted Whole Blood Using a High-Performance Inline Filter

Background: The efficiency of prestorage leukodepletion of whole blood on the production of proinflammatory cytokines (IL-β, IL-6, IL-8 and TNF-α) was compared in two groups of nonfiltered and filtered whole blood. Material and Methods:Ten experiments were performed. In each experiment we took two whole blood units drawn from a pool. In one group the units were immediately filtered by the new inline filter Biofil integral on NPBI Compoflex system while in the second group they were maintained without leukodepletion at +4 °C. Results:The filter showed a mean log₁₀ depletion of 3.86 ± 0.08 (CV 2.1%) with a mean absolute number of leukocytes in the postfiltration units of 0.29 ± 0.049 × 10⁶ and a RBC recovery of 92.5 ± 1.1%. IL-6 and TNF-α remained at concentrations less than 1 pg/ml in the samples during the storage period both in the control and filtered units. IL-β was not significantly higher on days 0 and 35 in the two groups while IL-8 was observed to be increased at day 35 in 2 out of the 10 experiments (620 and 415 pg/ml, respectively). Conclusions:The inline filter Biofil in combination with an NPBI Compoflex system has a high performance in the leukodepletion of whole blood. Proinflammatory cytokines have a concentration in whole blood less than described in platelet concentrates, and prestorage leukodepletion seems to prevent cytokine accumulation.

Leukocyte Depletion and Storage of Single-Donor Platelet Concentrates

Background and objectives: Because of widespread use of leukocyte reduction in platelet concentrates (PCs) and the need to store such concentrates, we investigated the effects of leukocyte depletion on the quality of stored PCs. Materials and methods: Ten double-sized PCs were divided into 2 equal units which were tested simultaneously. One half was stored for 5 days after filtration through a polyester filter, the other one was stored unfiltered. Results: The volume of the 10 ‘oversized’ PCs was 483±40ml (mean ± standard deviation) and they contained 5.9± 1.5×10^11 platelets and 80±23×10^6 leukocytes. Filtration significantly reduced the leukocyte concentration (168±56/pl before, 6±4/μl after filtration) and leukocyte count (39.9±11.3×10^6 vs. 1.3±0.9×10^6; p<0.0005). Filtration caused a platelet loss of 16%, the platelet count decreasing not significantly from 2.91±0.75×10^11 to 2.40±0.94×10^11 (p = 0.26). After 5 days of storage all parameters of platelet function (platelet aggregation to several stimuli, hypotonic shock reaction [HSR] and platelet retraction), mean platelet volume, and pH and pCO(2) showed no advantage for PCs filtered prior to storage compared to PCs stored unfiltered. Moreover, platelet aggregation on day 5 using 4 agonists at 10 concentrations showed worse results in 4 assays in prestorage filtered PCs (collagen [4μg/ml: p<0.05, ADP [0.2 mM]: p<0.05, ADP [0.3 mM\\ p<0.05, thrombin [0.6 E/ml] : p<0.05). But there is no convincing trend in all aggregation tests, and HSR, presumably the most useful parameter, was not different on day 5. Conclusions: There is no advantage in terms of improved quality for prestorage leukodepletion of PCs. Taking into account the obvious disadvantages of filtration, such as platelet loss and increasing costs per transfusion, we conclude that pre- or post-storage filtration of single-donor PCs should be done only for patients who have a clear indication for the transfusion of leukocyte-poor blood products.

Leukocyte depletion and storage of single-donor platelet concentrates.

Because of widespread use of leukocyte reduction in platelet concentrates (PCs) and the need to store such concentrates, we investigated the effects of leukocyte depletion on the quality of stored PCs. Ten double-sized PCs were divided into 2 equal units which were tested simultaneously. One half was stored for 5 days after filtration through a polyester filter, the other one was stored unfiltered. The volume of the 10 "oversized' PCs was 483 +/- 40 ml (mean +/- standard deviation) and they contained 5.9 +/- 1.5 x 10(11) platelets and 80 +/- 23 x 10(6) leukocytes. Filtration significantly reduced the leukocyte concentration (168 +/- 56/microliter before, 6 +/- 4 /microliter after filtration) and leukocyte count (39.9 +/- 11.3 x 10(6) vs. 1.3 +/- 0.9 x 10(6); p < 0.0005). Filtration caused a platelet loss of 16%, the platelet count decreasing not significantly from 2.91 +/- 0.75 x 10(11) to 2.40 +/- 0.94 x 10(11) (p = 0.26). After 5 days of storage all parameters of platelet function (platelet aggregation to several stimuli, hypotonic shock reaction [HSR] and platelet retraction), mean platelet volume, and pH and pCO2 showed no advantage for PCs filtered prior to storage compared to PCs stored unfiltered. Moreover, platelet aggregation on day 5 using 4 agonists at 10 concentrations showed worse results in 4 assays in prestorage filtered PCs (collagen [4 micrograms/ml: p < 0.05, ADP [0.2 mM]: p < 0.05, ADP [0.3 mM]: p < 0.05, thrombin [0.6 E/ml]: p < 0.05). But there is no convincing trend in all aggregation tests, and HSR, presumably the most useful parameter, was not different or day 5. There is no advantage in terms of improved quality for prestorage leuko-depletion of PCs. Taking into account the obvious disadvantages of filtration, such as platelet loss and increasing costs per transfusion, we conclude that pre- or post-storage filtration of single-donor PCs should be done only for patients who have a clear indication for the transfusion of leukocyte-poor blood products.

The tumor growth-promoting effect of allogeneic blood transfusions.

Over the past decade, many studies have suggested that allogeneic blood transfusions (ABT) may adversely affect a recipient. The ABT-associated deleterious effects include the development of transfusion reactions, graft-versus-host disease, alloimmunization, and immunomodulation. While the ABT-associated immunosuppressive effects might be beneficial for recipients of kidney allografts, in reducing the relapse rate in patients with Crohn's disease, and in ameliorating the rate of abortion in women with recurrent spontaneous abortions; evidence is accumulating that the immunosuppression associated to perioperative ABT might adversely affect overall prognosis in patients with a malignancy undergoing curative cancer surgery. In addition, the ABT-associated immunomodulation has been reported to be associated with an increased risk for postoperative bacterial infections. Data from both inbred and outbred experimental animal models indicate that ABT promote tumor growth. Evidence is available that this ABT-promoting tumor growth effect can be adoptively transferred to naive animals, using splenic immunocytes. Furthermore, data from the experimental animal models indicate that the ABT effect on the growth of tumors is due to the presence of the donor leukocytes in the transfused allogeneic blood, and that this deleterious effect can be ameliorated by the pre-storage leukodepletion of the allogeneic blood. Importantly, recent evidence suggests that post-storage leukodepletion is inefficacious in preventing the ABT-associated tumor growth promotion effect. While results from studies in experimental animals cannot necessarily be extrapolated to the clinical situation, these studies suggest that ABT promote tumor growth and that pre-storage leukodepletion ameliorates this effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth Enhancement of Established Tumors by Allogeneic Blood Transfusion in Experimental Animals and Its Amelioration by Leukodepletion: The Importance of the Timing of the Leukodepletion

We had reported previously (Blood 81:1880, 1993) that allogeneic blood transfusions (ABT) administered before the infusion of tumor cells in both inbred and outbred experimental animals promote tumor growth and that this effect can be ameliorated by leukodepletion. To better reproduce the human situation, we evaluated, in this present study, the effect of ABT in animals with established tumors using enumeration of pulmonary metastatic nodules as the end point. The role of allogeneic blood component transfusions in promoting tumor growth and the relative efficacy of prestorage versus poststorage leukodepletion of the ABT in preventing tumor growth enhancement were also evaluated. In an inbred murine animal model, C57Bl/6J mice were administered nonleukodepleted allogeneic (ABT), leukodepleted allogeneic (LD-ABT), or syngeneic (SBT) blood transfusions after the intravenous infusion of syngeneic methylcholanthrene-induced fibrosarcoma cells using two different protocols. A significant increase in the number of pulmonary nodules was observed in those mice that received ABT, in both protocols, compared to animals transfused with SBT or LD-ABT. Significantly higher numbers of pulmonary nodules were also seen in mice transfused with allogeneic buffy-coat leukocytes compared with mice that received either nonleukodepleted allogeneic plasma or LD-ABT. In an outbred animal (rabbit) model, recipient rabbits were administered either nonleukodepleted ABT, prestorage LD-ABT, poststorage LD-ABT, or SBT on days +4 and +9 after the infusion of syngeneic epithelial tumor cells. A significant increase in the number of pulmonary nodules was seen in rabbits that received nonleukodepleted ABT compared to animals transfused with SBT. Significantly lower numbers of pulmonary nodules were observed in rabbits that received prestorage LD-ABT compared to animals transfused with poststorage LD-ABT, but no significant difference was seen in rabbits that received poststorage LD-ABT compared with animals transfused with nonleukodepleted ABT. These studies show that ABT promote tumor growth of established animal tumors, that the ABT-induced tumor growth effect is related to the presence of donor allogeneic leukocytes, and that this effect can be ameliorated by prestorage leukodepletion. The present results also provide evidence for the lack of efficacy of poststorage leukodepletion in preventing ABT tumor growth promotion.(ABSTRACT TRUNCATED AT 400 WORDS)

Growth enhancement of established tumors by allogeneic blood transfusion in experimental animals and its amelioration by leukodepletion: the importance of the timing of the leukodepletion

We had reported previously (Blood 81:1880, 1993) that allogeneic blood transfusions (ABT) administered before the infusion of tumor cells in both inbred and outbred experimental animals promote tumor growth and that this effect can be ameliorated by leukodepletion. To better reproduce the human situation, we evaluated, in this present study, the effect of ABT in animals with established tumors using enumeration of pulmonary metastatic nodules as the end point. The role of allogeneic blood component transfusions in promoting tumor growth and the relative efficacy of prestorage versus poststorage leukodepletion of the ABT in preventing tumor growth enhancement were also evaluated. In an inbred murine animal model, C57Bl/6J mice were administered nonleukodepleted allogeneic (ABT), leukodepleted allogeneic (LD-ABT), or syngeneic (SBT) blood transfusions after the intravenous infusion of syngeneic methylcholanthrene-induced fibrosarcoma cells using two different protocols. A significant increase in the number of pulmonary nodules was observed in those mice that received ABT, in both protocols, compared to animals transfused with SBT or LD-ABT. Significantly higher numbers of pulmonary nodules were also seen in mice transfused with allogeneic buffy-coat leukocytes compared with mice that received either nonleukodepleted allogeneic plasma or LD-ABT. In an outbred animal (rabbit) model, recipient rabbits were administered either nonleukodepleted ABT, prestorage LD-ABT, poststorage LD-ABT, or SBT on days +4 and +9 after the infusion of syngeneic epithelial tumor cells. A significant increase in the number of pulmonary nodules was seen in rabbits that received nonleukodepleted ABT compared to animals transfused with SBT. Significantly lower numbers of pulmonary nodules were observed in rabbits that received prestorage LD-ABT compared to animals transfused with poststorage LD-ABT, but no significant difference was seen in rabbits that received poststorage LD-ABT compared with animals transfused with nonleukodepleted ABT. These studies show that ABT promote tumor growth of established animal tumors, that the ABT-induced tumor growth effect is related to the presence of donor allogeneic leukocytes, and that this effect can be ameliorated by prestorage leukodepletion. The present results also provide evidence for the lack of efficacy of poststorage leukodepletion in preventing ABT tumor growth promotion.(ABSTRACT TRUNCATED AT 400 WORDS).

An animal model of allogeneic donor platelet refractoriness: the effect of the time of leukodepletion

Approximately 50% of multi-transfused individuals become refractory to random donor platelets. Recent clinical data suggest that those patients receiving leukocyte-depleted blood products are less likely to become refractory to random donor platelets than recipients of non- leukocyte-depleted products. Leukocyte depletion can be performed immediately after collection of a unit of whole blood before its storage (prestorage leukodepletion) or just before the transfusion of the blood product to a recipient, after its storage (poststorage leukodepletion). However, the most appropriate time for the leukodepletion of blood products has not been established. The present study was undertaken to establish an animal model of allogeneic platelet refractoriness, and to compare the effect of prestorage and poststorage leukodepletion on the frequency of refractoriness to allogeneic donor platelets. In this model, two strains of rabbits were used: California Black rabbits were used as blood donors, while New Zealand White rabbits were used as recipients. Eight weekly infusions of nonleukodepleted allogeneic fresh blood resulted in an allogeneic platelet refractory rate of 91.2% (31/34). The prestorage leukodepletion of the donor blood was associated with a significantly higher allogeneic platelet survival and lower refractory rate (33.3%) to allogeneic platelets than poststorage leukodepletion (66.7%). Furthermore, the data suggest that cell-free plasma products are capable of inducing refractoriness to allogeneic donor platelets; the stored plasma having a greater likelihood of inducing such refractoriness than fresh plasma. Thus, these data provide evidence that the prestorage leukodepletion of allogeneic donor blood is associated with a lower frequency of refractoriness and better allogeneic platelet survival than poststorage leukodepletion.

An Animal Model of Allogeneic Donor Platelet Refractoriness: The Effect of the Time of Leukodepletion

Approximately 50% of multi-transfused individuals become refractory to random donor platelets. Recent clinical data suggest that those patients receiving leukocyte-depleted blood products are less likely to become refractory to random donor platelets than recipients of non-leukocyte-depleted products. Leukocyte depletion can be performed immediately after collection of a unit of whole blood before its storage (prestorage leukodepletion) or just before the transfusion of the blood product to a recipient, after its storage (poststorage leukodepletion). However, the most appropriate time for the leukodepletion of blood products has not been established. The present study was undertaken to establish an animal model of allogeneic platelet refractoriness, and to compare the effect of prestorage and poststorage leukodepletion on the frequency of refractoriness to allogeneic donor platelets. In this model, two strains of rabbits were used: California Black rabbits were used as blood donors, while New Zealand White rabbits were used as recipients. Eight weekly infusions of nonleukodepleted allogeneic fresh blood resulted in an allogeneic platelet refractory rate of 91.2% (31/34). The prestorage leukodepletion of the donor blood was associated with a significantly higher allogeneic platelet survival and lower refractory rate (33.3%) to allogeneic platelets than poststorage leukodepletion (66.7%). Furthermore, the data suggest that cell-free plasma products are capable of inducing refractoriness to allogeneic donor platelets; the stored plasma having a greater likelihood of inducing such refractoriness than fresh plasma. Thus, these data provide evidence that the prestorage leukodepletion of allogeneic donor blood is associated with a lower frequency of refractoriness and better allogeneic platelet survival than poststorage leukodepletion.