Leukocyte Depletion Filters Research Articles

Leukocytes-Depleting Filters Preferentially Remove Activated Leukocytes and Reduce the Expression of Surface Adhesion Molecules during the Simulated Extracorporeal Circulation of Human Blood

The effect of leukocyte-depleting filters on the total and activated leukocyte counts and the expression of surface adhesion molecules CD11b, CD18, and CD62L during the in vitro extracorporeal circulation of human blood was studied. A 200 ml blood sample was taken from 10 patients undergoing CABG surgery. The blood was circulated for 60 minutes within an experimental extracorporeal circuit. A leukocyte-depleting filter was attached in five circuits (filtered group). In five other circuits, no filter was used (controls). Total leukocyte counts were determined manually. Activated leukocytes were identified using nitroblue tetrazolium staining. The expression of CD11b, CD18, and CD62L was measured with flow cytometry. At 60 minutes, total leukocyte counts were reduced by 49% from the baseline values in the filtered group and 10% in the control group (p < 0.0001). Activated leukocyte counts decreased by 86% in the filtered group and increased by 116% in the control group (p < 0.0001). In the filtered group, the expression of CD11b, CD18, and CD612L decreased by 60%, 21%, and 79%, respectively, and in the control group it increased by 24%, 6%, and 28% (p < 0.0001). Leukocyte-depleting filters preferentially remove activated leukocytes and reduce the expression of CD11b, CD18, and CD62L during the in vitro extracorporeal circulation of human blood.

Autologous transfusion: An alternative to transfusion with banked blood during surgery for cancer

Autologous blood transfusion in surgery for cancer has been avoided because of the metastatic potential of reinfused malignant cells. This study determined whether viable tumour cells remain in the red cell concentrate after separation and whether blood transfusion filters remove these tumour cells before reinfusion. Units of banked blood were inoculated with tumour cell lines: breast cancer SKBr3; colon cancer COLO 320; lymphoma Daudi; erythroleukaemia K562. After processing with the Cell Saver, aliquots of the red cell concentrate and waste saline wash were examined for tumour cells and cultured. Tumour cells from all four cell lines were identified in the red cell concentrate but not in the waste saline wash. All the cell lines except Daudi grew from the red cell concentrate. Experiments on two of the cell lines (SKBr3 and COLO 320) were performed in which the red cell concentrate was either unfiltered (control) or filtered with SQ40S blood transfusion filter or RC100 leucocyte depletion filter. Both cell lines were present in the control samples and after filtration with SQ40S filters, and cells from these samples grew normally in culture. No tumour cells were evident after filtration with the RC100 filters and no growth of either cell line was found after 1 week in culture. The Cell Saver in combination with RC100 filters may be suitable for use during the surgical treatment of malignant disease.

Leukocyte removal efficiency of cell-washed and unwashed whole blood: an in vitro study

Leukocyte filtration of the cardiopulmonary bypass (CPB) perfusate after cardiac surgery has evolved as an important technique to prevent effector functions mediated by activated leukocytes. However, little is known about the filtration efficiency. Therefore, an in vitro study was conducted to define the leukocyte removal rate of a transfusion leukocyte-depletion filter, using cell-washed and unwashed whole porcine blood. In addition, the influence of different cell-washing protocols on the elimination rate of blood cells (leukocytes and platelets) was investigated. Fresh, diluted, pooled, heparinized, porcine blood was processed using either a high-flow (HF, n = 5) or quality-wash (QW, n = 5) protocol on a continuous auto-transfusion system, or was left unprocessed (control n=5). Thereafter, all samples were filtered using a transfusion leukocyte-depletion filter. Blood samples for measurement of hematocrit, white blood cell count, including leukocyte differentiation and platelet count, were taken before and after filtration. To compare the experimental groups, the removal rate was presented as the fraction of leukocytes or platelets removed per plasma volume. Cell washing significantly altered the fraction of leukocytes removed per plasma volume when compared to unprocessed blood (2.07 and 2.36 in the HF and QW groups, respectively, versus 1.34 in the control group, p = 0.008 for both). No statistically significant difference in leukocyte removal rate was observed between the different cell-washing protocols. The leukocyte differential count showed that, during all experiments, the neutrophils were removed most efficiently (99.7%). Overall, significantly more platelets were depleted after cell washing compared to the control group (1.47 and 1.60 in the HF and QW groups, respectively, versus 1.12 in the control group, p =0.008 and 0.032, respectively). Furthermore, the amount of blood that could be filtered using a single pass technique did not significantly differ between the experimental groups. However, a larger variation in the total amount of filtered blood was observed in the unprocessed group (570+/-398 mL) compared to the cell-washed groups (360+/-42 and 430+/-97 mL in the HF and QW groups, respectively). In conclusion, blood processing with an auto-transfusion system significantly enhances the leukocyte and platelet removal efficiency of the transfusion leukocyte-depletion filter that was studied. In particular, neutrophils were efficiently removed.

Filter Buffy Coats (FBC): A source of peripheral blood leukocytes recovered from leukocyte depletion filters

In compliance with federal regulations, blood banks routinely use leukocyte depletion filters to eliminate contaminating leukocytes from blood products such as red blood cell and platelet concentrates. We developed and optimized conditions to elute leukocytes adsorbed to these filters; resulting in leukocyte suspensions which we termed Filter Buffy Coats (FBCs). These Filter Buffy Coats can replace standard buffy coats for various research applications. After optimizing both the filter elution medium as well as elution protocols, we compared commonly used leukocyte depletion filters from four different manufacturers. Relative fractions as well as total recoveries of leukocyte subsets, such as lymphocytes, monocytes and granulocytes, found in Filter Buffy Coats were identified and compared among the filters as well as to standard buffy coats and whole blood. Flow cytometric analysis of Filter Buffy Coats confirmed the presence of T- and B-lymphocytes, NK cells and monocytes. Furthermore, a significant quantity of CD34 + hematopoietic stem or progenitor cells (HSC/HPC) was detected in Filter Buffy Coats prepared from different filters, thus making FBCs a valuable source for research on HSC/HPC. Colony assays revealed that most of these CD34 + cells are functional. Using immunomagnetic cell sorting (MACS), we isolated a variety of leukocyte populations from FBC mononuclear cells (Filter-PBMCs) including T lymphocytes (CD4 +, CD8 +, CD3 +), B lymphocytes (CD19 +), NK cells (CD56 +), HSC/HPC (CD34 +, CD133 +) or dendritic cells (BDCA-4 +). Functional properties of Filter-PBMCs, as well as of some of these isolated leukocyte populations, were confirmed using standard assays. In summary, Filter Buffy Coats are a valuable and convenient source of different peripheral leukocyte populations and can replace standard buffy coat preparations for research applications.

The Effect of Storage on the Survival of Cancer Cells in Blood and Efficient Elimination of Contaminating Cancer Cells by a Leukocyte Depletion Filter

Preoperative autologous blood pooling has been employed in patients with malignant tumor. However, it has not been reported how the survival period of tumor cells contaminating the preoperative pooled blood changes corresponding to the storage period. Intraoperative blood salvage (IBS) is used together with preoperative blood pooling. However, IBS in oncologic surgery is generally regarded as a contraindication. In the current study, using cytokeratin 19 (CK-19) mRNA reverse transcription polymerase chain reaction method, we examined the survival period of cultured cancer cells in the pooled blood and the efficacy of irradiation and leukocyte depletion filter in eliminating cancer cells in the blood. Expression of CK-19 mRNA was observed in the pooled blood stored for 21 days. The number of cancer cells decreased to about 1/10 in the blood stored for 14 days. We irradiated blood with cancer cells with doses of 25 Gy or 100 Gy. No change was observed in the amplified CK-19 signal strength immediately after and 1 day after irradiation at 100 Gy. After filtration of blood with cancer cells through the leukocyte depletion filter, no CK-19 mRNA was detected. Blood filtration with the leukocyte depletion filter was effective in eliminating cancer cells in the blood.

Analysis of leukocyte binding to depletion filters: role of passive binding, interaction with platelets, and plasma components

Since limited knowledge exists on the mechanisms which regulate cell binding to leukocyte removal filter surfaces, we investigated the binding patterns of leukocytes to individual layers of leukocyte depletion filters. After passage of 1 unit of whole blood, blotting of isolated filter layers on glass slides or elution of cells from filter layers revealed that most leukocytes were located within the first 10 of a total of 28 filter layers, peaking at layers 6 to 8, with granulocytes binding on average to earlier filter layers than lymphocytes. Leukocytes preincubated with inhibitors of actin activation showed unchanged distribution between filter layers, suggesting that cytoskeletal activation does not significantly contribute to their binding. When leukocytes were directly incubated with single filter layers, binding of up to 30% of input cells was recorded in the absence of Ca(2+). Immunohistological analyses showed colocalization of platelets and leukocytes, with co-clustering of platelets and leukocytes. Monocytes and to some degree lymphocytes but not granulocytes competed with platelets for filter binding. Precoating of filter layers with individual plasma components showed that hyaluronic acid, plasma type fibronectin, and fibrinogen all increased the binding of leukocytes compared with albumin coating. In conclusion, leukocytes can bind passively to filters in a process which does not require Ca(2+), which is independent of cytoskeletal activation and which may depend on individual plasma components. These results are of importance when new selective cell enrichment or depletion strategies through specific filters are envisaged.

Can a leukocyte depletion filter (LDF) reduce the risk of reintroduction of hepatocellular carcinoma cells?

During liver transplantation for hepatocellular carcinoma (HCC) patients, HCC could theoretically be introduced into the systemic circulation when salvaged blood is used with an autotransfusion device. Several reports have shown that some types of leukocyte depletion filters (LDFs) could completely reduce the risk for reintroducing some types of tumor cells. In this study, we tested the ability of the LDF (RCEZ1T, Pall Biomedical Co, NY, USA) to reduce the risk for reintroducing HCC cells in vitro by using a very sensitive detection method. We divided the test group into 6 groups: group I was 10 cells, group II was 20 cells, group III was 2 x 10(3) cells, group IV was 2 x 10(5) cells, group V was 2 x 10(6) cells, and group VI was 2 x 10(7) cells. The counted cells in 200 mL saline were passed through the RCEZ1T using the force of gravity. To identify the presence of cells, the pellet was resuspended, and polymerase chain reaction (PCR) was performed. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a housekeeping gene, was used as a primer. In groups I and II, the HCC cells were completely filtered in all experiments. However, in groups III, IV, and V, the HCC cells were not completely filtered in a few of the repeated experiments, with the unfiltered rate of tumor cells being between 8% and 20%. In group VI, the HCC cells were not completely filtered in all the repeated experiments. In conclusion, the RCEZ1T filter markedly reduced the risk for reintroduction of HCC cells. However, at high HCC cell load the filter cannot completely remove all the tumor cells. Further studies are required to assess the impact in clinical settings.

The Clinical Effects and Mechanisms of Leukocyte Depletion Filters During Cardiac Surgery

ctivated leukocytes play a key role in thegeneralized inflammatory response thatoccurs after cardiac surgery. To minimize or evenprevent postoperative tissue injury, it is thusattractive to target the leukocytes. Various methodshave been tried to attenuate nearly all stages of theinflammatory pathway. Currently, the mostimportant strategies try to prevent leukocyteactivation, such as heparin coated bypass circuits,to modulate the inflammatory response by the useof pharmacological agents, such as aprotinin andcorticosteroids, and to remove factors that triggerthe inflammatory response, such as ultra-filtration.Although leukocyte depletion by means offiltration is common in blood banks, the applicationduring surgery is a relatively new development.The basic idea is to remove activated leukocytes,thereby minimizing organ injury. One of thebenefits of leukocyte depletion is that in contrastto pharmacological interventions, side effects areminimal. In this review we will not only considerclinical studies regarding leukocyte depletionduring cardiac surgery, but also go more in depthabout the filtration mechanisms in the filters, as thismay help to understand the application of thistechnology.

Leucocyte filtration of residual heart-lung machine blood in children undergoing congenital heart surgery

Cardiopulmonary bypass (CPB) leads to a generalized inflammatory reaction, resulting in increased postoperative leucocyte counts and decreased pulmonary function. In adults, removal of leucocytes from the residual heart-lung machine blood after CPB improved postoperative oxygenation. In children, however, the clinical effects of leucocyte filtration of the residual heart-lung machine blood are unknown. Therefore, we measured postoperative leucocyte counts and arterial blood oxygenation in children undergoing congenital cardiac surgery in a randomized prospective study. Anaesthesia and CPB were standardized. After CPB, the residual heart-lung machine blood was collected as usual. In a group of 25 children, this blood was filtered with a leucocyte depletion filter before transfusion. A control group of 25 children received this blood unfiltered. We found that the postoperative leucocyte counts were significantly lower in the filter group than in the control group (p = 0.02, repeated measurements ANOVA). This difference reached a maximum on the second postoperative day (12.9 x 10(9)/L filter versus 15.9 x 10(9)/L control, p = 0.02, Student's t-test). Values for the arterial blood oxygenation on the first postoperative day were not different between the two groups (15.5 +/- 1 kPa filter versus 14.6 +/- 1.3 kPa control, p = 0.57, Student's t-test). We conclude that leucocyte filtration of the residual heart-lung machine blood reduced systemic leucocyte counts, but did not improve arterial blood oxygenation in children after congenital heart surgery.

Assessment of removal of human cytomegalovirus from blood components by leukocyte depletion filters using real-time quantitative PCR

AbstractTo assess removal of cytomegalovirus (CMV) by leukocyte depletion (LD) filters, we developed a spiking model of latent virus using peripheral blood mononuclear cells (PBMCs) infected by coculture with CMV-infected human fibroblasts. Infected PBMCs were purified by dual magnetic column selection and then spiked into whole blood units or buffy coat pools prior to LD by filtration. CMV load and fibroblast contamination were assessed using quantitative CMV DNA real-time PCR and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) of mRNA encoding the fibroblast-specific splice variant of prolyl-4-hydroxylase, respectively. After correcting for fibroblast-associated CMV, the mean CMV load was reduced in whole blood by LD from 7.42 × 102 to 1.13 copies per microliter (2.8110log reduction) and from 3.8 × 102 to 4.77 copies per microliter (1.910log reduction) in platelets. These results suggest that LD by filtration reduces viral burden but does not completely remove CMV from blood components. (Blood. 2004;103:1137-1139)

Cell Salvage in the Presence of Malignancy

SUMMARYIn cancer surgery there is high and ever increasing demand for blood. Transfusion‐related immunomodulation induced by the allogeneic barrier and by storage lesions with an increased risk of postoperative infections and tumor recurrence, is of particular bearing in this patient group. Intraoperative cell salvage is contraindicated as confirmed by the demonstration of vital tumor cells in the shed blood. Sensitive detection techniques have shown that leukocyte depletion filters are of limited capacity in reducing the number of tumor cells in. In contrast, a 12‐log reduction in proliferating cells is to be expected from a 50 Gy gamma irradiation, and has been experimentally confirmed. The safety of irradiation of fresh, unstored RBCs is demonstrated by minimal hemolysis, normal levels of 2,3‐DPG and ATP, and by a 24‐hour survival rate exceeding that of the venous control. Cell salvage with blood irradiation is a practical method allowing effective saving of blood in cancer surgery.

Bacterial reduction by cell salvage washing and leukocyte depletion filtration.

Blood conservation techniques are being increasingly used because of the increased cost and lack of availability of allogeneic blood. Cell salvage offers great blood savings opportunities but is thought to be contraindicated in a number of areas (e.g., blood contaminated with bacteria). Several outcome studies have suggested the safety of this technique in trauma and colorectal surgery, but many practitioners are still hesitant to apply cell salvage in the face of frank bacterial contamination. This study was undertaken to assess the efficacy of bacterial removal when cell salvage was combined with leukocyte depletion filtration. Expired packed erythrocytes were obtained and inoculated with a fixed amount of a stock bacteria (Escherichia coli American Type Culture Collections [ATCC] 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, or Bacteroides fragilis ATCC 25285) in amounts ranging from 2,000 to 4,000 colony forming units/ml. The blood was processed via a cell salvage machine. The washed blood was then filtered using a leukocyte reduction filter. The results for blood taken during each step of processing were compared using a repeated-measures design. Fifteen units of blood were contaminated with each of the stock bacteria. From the prewash sample to the postfiltration sample, 99.0%, 99.6%, 100%, and 97.6% of E. coli, S. aureus, P. aeruginosa, and B. fragilis were removed, respectively. Significant but not complete removal of contaminating bacteria was seen. An increased level of patient safety may be added to cell salvage by including a leukocyte depletion filter when salvaging blood that might be grossly contaminated with bacteria.

Filters in anaesthesia and intensive care.

The use of various types of filters in anaesthesia and intensive care seems ubiquitous, yet authentication of the practice is scarce and controversies abound. This review examines evidence for the practice of using filters with blood and blood product transfusion (standard blood filter, microfilter, leucocyte depletion filter), infusion of fluids, breathing systems, epidural catheters, and at less common sites such as with Entonox inhalation in non-intubated patients, forced air convection warmers, and air-conditioning systems. For most filters, the literature failed to support routine usage, despite this seemingly being popular and innocuous. The controversies, as well as guidelines if available, for each type of filter, are discussed. The review aims to rationalize the place of various filters in the anaesthesia and intensive care environment.

Effects of Leukocyte Depletion Filters on Matrix Metalloproteinase Activation in an Extracorporeal Circulation Circuit

Matrix metalloproteinases (MMPs) are a family of endopeptidases that function to remodel tissue during both normal physiology and pathology. Research performed by the Medical University of South Carolina found an increased release of several MMP species during cardiopulmonary bypass (CPB), including the subtype MMP-9, but whether and to what degree the extracorporeal circulation circuit (ECC) induces the release of MMPs has yet to be determined. Human bank whole blood scheduled for discard was obtained and exposed to an ECC. The first set of studies (N = 8) was performed with a loop circuit using a standard arterial line filter. A leukoreduction filter was incorporated during the first 30 min of the pump run for the second set of trials; the leukoreduction filter was then bypassed and a standard arterial filter used for the remaining 60 minutes on pump (N = 8). Blood samples were drawn at four time points for analysis (baseline, 30, 60, and 90 min). Data were analyzed using repeated measures analysis of variance with betweensubjects factors, and a p value of less than .1 was considered statistically significant. The MMP-9 level increased by 130.44% at 90 min on pump in the standard arterial filter group and decreased by 34.62% at 90 min on pump in the leukoreduction group. There was a significant difference between the baseline MMP-9 level and the MMP-9 concentrations at 30, 60, and 90 min for both groups (p = .0348); there was a significant difference in MMP-9 levels between the two filter groups (p = .0611). The present study found a significant increase in MMP-9 levels when blood was exposed to an ECC with a standard arterial filter. The use of a leukoreduction filter significantly reduced MMP-9 concentrations as compared to baseline levels in this study. Leukocyte depletion filtration may serve to benefit CPB patients by attenuating the inflammatory response and disrupting pathways that govern such mediators as the MMPs.

Leukocyte Depletion as a Mechanism for Reducing Neutrophil-Mediated Ischemic-Reperfusion Injury during Transplantation

Patients undergoing transplantation are at high risk for leukocyte-mediated morbidity because of activated neutrophils and oxygen free radicals. This type of injury is most prominent during the reperfusion stage of transplantation. When tissue becomes ischemic, normal oxidation is altered (2). As oxygen is reintroduced to the system, oxygen free radical formation occurs via the oxidation of hypoxanthine by xanthine oxidase, causing destruction of the endothelium, increased permeability, and decreased organ function (2). In addition, neutrophils that may have already been activated by contact activation from the cardiopulmonary bypass circuit, accumulate in the ischemic organ at reperfusion (9,10). Activated neutrophils then release oxygen metabolites and proteolytic enzymes, which further destroy the integrity of the vascular endothelium (11). This insult can cause edema, capillary plugging, and poor graft function (12). Recent attempts have been made to decrease the mediators of ischemic-reperfusion injury. Perhaps the most advantageous of these attempts is the removal of leukocytes during reperfusion. This has been successfully achieved using leukocyte-depleting filters before exposing the organ to systemic blood flow (14). This article is a review of ischemic-reperfusion injury and the use of leukocyte depletion during reperfusion of transplanted organs.

Persistence of HTLV-I in blood components after leukocyte depletion

AbstractThe human T-cell leukemia virus HTLV-I is a transfusion-transmissible retrovirus targeting T lymphocytes for which screening is not currently undertaken in United Kingdom blood donors. The introduction of universal leukocyte depletion (LD) of the United Kingdom blood supply raises the question as to the degree of protection afforded by this procedure against HTLV-I transmission by blood components. HTLV-I viral DNA removal by leukocyte-depleting filters was assessed in units of whole blood and platelets by real-time quantitative polymerase chain reaction (PCR) and by nested PCR for HTLV-I Tax DNA. We examined HTLV-I removal by LD filters using a model system of blood units containing exogenous spiked HTLV-I–positive MT-2 cells at a relevant concentration and whole blood donations from asymptomatic HTLV-I carriers. T-lymphocyte removal was assessed in parallel by measurement of endogenous subset-specific CD3 mRNA. In the MT-2 model system we observed 3.5 log10 to 4 log10 removal of HTLV-I Tax DNA by filtration of whole blood and 2 log10 to 3 log10 removal across platelet filters with 13 of 16 whole blood and 8 of 8 platelet units still positive after filtration. Despite 3 log10 to 4 log10 viral removal, HTLV-I Tax DNA could be detected after whole blood filtration in asymptomatic carriers with viral loads above 108 proviral DNA copies/L. T-lymphocyte removal was also between 3.5 log10 and 4.5 log10. HTLV-I provirus removal was incomplete in the model system and in asymptomatic carriers with viral loads greater than 108 copies/L. These results suggest that LD alone may not provide complete protection from HTLV-I transmission by transfusion.

Use of the Cell Saver in Oncologic Surgery

SUMMARYUse of the cell saver in oncologic surgery is controversial because of the risk of reinfusion of cancer cells remaining in the packed erythrocytes. Experimental and clinical studies have indeed confirmed the presence of residual cancer cells in packed red cells. However, six clinical studies with a limited number of patients showed no metastatic spread after processing of the blood with a cell saver. The adjunctive use of a leukocyte depletion filter (LDF) greatly reduces the number of cancerous cells in the pack whereas irradiation of the pack with 50 Gy destroys all the cancer cells. Strictly speaking, the stringent application of this safety principle would require use of a cell saver only in conjunction with an irradiator. Studies indicate that cancer cell seeding from infiltrative tumors seems to be greater than that observed when a cell saver is used. In the final analysis, we feel that it is reasonable to use the cell saver in oncologic surgery, if possible with a leukocyte filter, not only in cases of unexpected bleeding risk but also during scheduled procedures with a high risk of massive blood loss.

Universal leukoreduction of cellular blood components in 2001? No.

Leukocytes are known to have a number of biologic effects associated with allogeneic blood transfusion ❚Table 1❚. The potential clinical importance of these effects, which are the focus of current debate over the merits of “universal” leukocyte reduction (leukoreduction; cellular components with <5 × 106 leukocytes) include the following: febrile-associated transfusion reactions (FATRs), transfusion-related alloimmunization to platelets, and transfusion-related immunomodulation. Several recent reviews1,2 of this topic, along with commentaries3-6 about the use of leukocytedepleted blood components, have been published. The Blood Products Advisory Committee (BPAC) to the US Food and Drug Administration (FDA) voted 13-0 on September 18, 1998, in favor of universal leukoreduction of blood components,7 but the minutes stated that many committee members agreed there were insufficient good studies, and everyone wanted more data.8 To date, both leukoreduced and nonleukoreduced blood components remain FDA-approved. This commentary will summarize my view of this controversy and the need for additional controlled clinical trials to provide data to resolve this issue. ❚Table 2❚ summarizes the percentage of blood components transfused that were leukoreduced in the United States in 1994 and 1997. The percentages for RBCs (17.6% and 18.3%) and platelets (16.5% and 15.5%) remained static, despite commercial advertisements to clinicians about leukocyte-depletion filters during this period.9 For the first 9 months of 1999, 3,592 (13%) of 27,663 RBC units transfused at our hospital were leukoreduced; our indications for leukoreduction reflect those published previously,4 and are summarized in ❚Table 3❚. FATRs occur in only 0.5% of RBC transfusions; of these, 18% and 8% of patients experience a second or third FATR.10 Approximately 18% of platelet transfusions are

Removal of Hepatocarcinoma Cells From Blood via Cell Washing and Filtration Techniques

Utilization of autotransfusion during tumor resection remains controversial due to viability of carcinoma cells remaining in collected blood. The purpose of this study was to evaluate autotransfusion techniques combined with leukocyte depleting filters (LDF) for removal of hepatocarcinoma cells from autotransfusate. An in vitro model was created by contaminating expired human erythrocytes with cultured hepatocarcinoma (HEP G2) cells. Autotransfusion devices evaluated were Cobe BRAT2, Sorin STAT-P, and Fresenius CATS. Autotransfusate collected from varying processing conditions were filtered using the Pall Leukoguard RS or Pall Purecell RCQ LDF. Carcinoma concentrations were quantified via Coulter Counter technology. The CATS exhibited higher concentrations of cancer cells in the autotransfusate prior to washing, a 449% increase. This was significantly higher than either the BRAT2 or STAT-P, 350% and 315% respectively. Post washing HEP G2 concentrations in the BRAT2 were significantly higher than the STAT-P and CATS. Doubled wash volumes removed more HEP G2 cells in all trials, reaching statistical significance only in the CATS. LDF resulted in a significant 75% reduction of HEP G2 cells, with no difference between filters. While combination use of autotransfusion devices and leukocyte depleting filters did result in a product with concentrated hematocrit, no technique removed all hepatocarcinoma cells.

保育器内の低出生体重児の赤血球輸血に及ぼす放射線照射と白血球除去フィルター併用の影響

We investigated the effect of irradiation and leukocyte filtration on red cells in MAP solution (RC-MAP) for premature infants.RC-MAPs were stored for 3 or 7 days and pretreated with 15-Gy irradiation and a leukocyte depletion filter, with either the irradiation or filtration performed first. Infusion was performed using an infusion pump for 8hr at a speed of 2ml/hr through a 4-ml, 100-cm tube and a 24G needle passing into an infant incubator warmed to 34°C.Free hemoglobin concentration in the supernatant of tested RC-MAP stored 7 days and irradiated after filtration was increased to the maximum level of 42.6mg/dl.Potassium ion level in the supernatants and ATP and 2, 3-DPG concentration in red cells from tested RC-MAP were similar to pretreated values. Maximum potassium ion level was increased to 23.5mEq/l.Our results showed that both irradiation and filtration against RC-MAP solutions stored for 3 or 7 days is safe for use with premature infants in warmed incubators. However, further investigation is necessary to clarify the risk of bacterial contamination in such transfusion situations.