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Results for “Leukocyte Reduction Procedures”

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At least 19 recordsLinked to original sources

PubMed2005

Total leukocyte control for elective coronary bypass surgery does not improve short-term outcome.

BACKGROUND: Despite early promise as a means of reducing the inflammatory response to surgery and subsequent organ damage, the evidence of the clinical value of leukocyte filtration remains equivocal. METHODS: Three hundred patients presenting for routine coronary artery bypass surgery were randomized to a total leukocyte filtration group (filters in five different locations) and a control group with a standard 40-mum filter in the bypass return line only. Data on efficacy and safety of leukocyte filtration were collected by research and postoperative care staff who were blinded to the mode of filtration. RESULTS: Leukofiltration achieved a transient fall in white cells immediately after surgery (p = 0.07) and a sustained fall in platelets, which was still significant on the second postoperative day (p = 0.0001). However, there were no significant differences in postoperative hospital stay, the primary outcome variable (p = 0.35), in ICU stay (p = 0.92), or mortality (p = 1.0). There were no differences in postoperative cardiac status including cardiac output (p = 0.16), inotrope (p = 0.93) or balloon pump (p = 0.48) requirement, or 24-hour troponin (p = 0.60). Similarly there were no differences in pulmonary or renal function (intubation time (p = 0.83), respiratory index (p = 0.19) rise in creatinine (p = 0.13) or hemofiltration (1.0)). Leukofitration was not associated with a statistically significant increase in bleeding or requirement for blood or blood products. It was associated with a decrease approaching significance (p = 0.1) in number and severity of postoperative wound infections. Three filters were blocked during use but were changed without incident or compromise to patient safety. CONCLUSIONS: Leukocyte filtration is safe but not efficacious in improving short-term outcome.

Aged↗

PubMed2005

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.

Blood Cells↗

PubMed2005

A novel accessory role of neutrophils in concanavalin A-induced hepatitis.

Concanavalin A (Con A)-induced hepatitis has been investigated as a model of T cell-mediated liver injury, in which IFN-gamma plays an essential role by inducing apoptosis of liver cells. Since a large number of neutrophils infiltrate into the liver in the model, the role of neutrophils was investigated in this study. Con A hardly caused liver injury in neutrophil-depleted mice, as assessed as to the plasma alanine aminotransferase level as well as histochemistry. Neutrophil-depleted mice also failed to produce IFN-gamma. Intracellular IFN-gamma staining revealed that, among liver leukocytes, T and NK cells but not neutrophils are the main producers of IFN-gamma. Nylon wool-purified "T cells", however, failed to produce IFN-gamma in response to Con A in vitro, while the production was restored by the addition of neutrophils. Overall, this study suggests that neutrophils play a novel accessory role in IFN-gamma production in Con A-induced hepatitis.

Alanine Transaminase↗

PubMed2005

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.

Antigens, CD↗

PubMed2006

Leukocyte filtration to decrease the number of adherent leukocytes in the cerebral microcirculation after a period of deep hypothermic circulatory arrest.

OBJECTIVE: Cardiopulmonary bypass and hypothermic circulatory arrest induce a systemic inflammatory response, including a cascade of leukocyte and endothelial cell activity, during the postischemic reperfusion phase. Accumulation of leukocytes in the brain can lead to neurologic problems after cardiac surgery. The beneficial effects of a leukocyte-depleting filter have been documented, but because of contradictory results the underlying function of the filter remains unclear. METHODS: Twenty-two juvenile piglets (6 to 8 weeks) were randomly assigned to undergo cardiopulmonary bypass with or without a leukocyte-depleting filter 60 minutes before and 60 minutes after a 75-minute hypothermic circulatory arrest at 18 degrees C. The cerebral vessels were visualized with intravital microscopy through a cranial window placed over the parietal cortex. Rhodamine staining was used to observe adherent and rolling leukocytes in the cerebral postcapillary venules. The animals were electively killed 1 hour after weaning from cardiopulmonary bypass. RESULTS: There were no significant differences between the study groups regarding hemodynamic data. Numbers of adherent activated leukocytes were lower in the leukocyte filtration group, reaching borderline statistical significance when assessed throughout the experiment (between-groups P = .069) and actual statistical significance when assessed during the rewarming period (between-groups P = .029). CONCLUSION: The leukocyte-depleting filter succeeded in reducing the number of adherent leukocytes during the reperfusion period in an experimental operation with deep hypothermic circulatory arrest. Such a filter thus could mitigate cerebral reperfusion injury after cardiac surgery.

Animals↗

PubMed2006

Extracellular accumulation of bioactive substances; interleukin-1beta (IL-1beta) and plasminogen activator inhibitor-1 (PAI-1) in stored blood units and relation to bacterial contamination.

Bacterial contamination of blood and its cellular components remains an unresolved problem in transfusion medicine and is considered to be the most common microbiological cause of transfusion associated morbidity and mortality. The present work was designed to explore the levels of two bioactive compounds interleukin-1 beta (IL-1beta) and plasminogen activator inhibitor-1 (PAI-1) in stored blood units and their relation to bacterial contamination of these units. This study was conducted on 112 blood units obtained from blood bank of Mansoura University Children Hospital. Sequential blood samples were obtained both immediately at donation and after 10 days for measurement of IL-1beta and PAI-1 and for bacterial culture by BACTEC 9050 system. There was statistically significant increase in both IL-1 beta and PAI-1 (P = 0.0001) after 10 days of blood units storage. Bacteriological culture revealed no growth in 68% and positive growth in 32% of blood units. The commonest isolated organism was Staphylococcus aureus (15%) followed by Staphylococcus epidermedis (13%) then Yersinia sp. and Enterobacter sp. (2%) for each. From the present study we could conclude that stored blood units contain platelets and WBCs derived bioactive substances PAI-1 and IL-1beta which increase with the duration of blood storage. Furthermore, the extended duration of storage carries the danger of blood contamination by bacteria. Automated blood culture system seems to be helpful in identification of bacterial contamination of blood units. We recommend fresh blood transfusion as early as possible and the practice of Leucofiltration to avoid blood transfusion complications.

Adult↗

PubMed2006

Pneumonia as a complication of blood product transfusion in the critically ill: transfusion-related immunomodulation (TRIM).

BACKGROUND: An increased risk of postoperative infection (including pneumonia) attributable to the receipt of allogeneic blood transfusion has been investigated as a possible manifestation of transfusion-related immunomodulation (TRIM) in 16 randomized controlled trials (RCTs) and approximately 40 observational studies. OBJECTIVES: This review categorizes RCTs and observational studies with regard to the inference that they permit about possible mediators of TRIM-allogeneic white cells (WBCs), WBC-derived soluble mediators, and/or allogeneic plasma-and examines whether the totality of the clinical evidence supports an association between allogeneic blood transfusion and postoperative infection. RESULTS: When all available studies are considered together in meta-analyses, three types of studies show no increased risk of postoperative infection in association with allogeneic blood transfusion: a) RCTs comparing recipients of buffy-coat-reduced and prestorage-filtered, WBC-reduced allogeneic red cells; b) RCTs comparing recipients of allogeneic and autologous blood; and c) observational studies comparing patients transfused before and after implementation of WBC reduction. RCTs comparing recipients of nonbuffy-coat-reduced and WBC-reduced red blood cells may point to a TRIM effect, but they cannot yet be subjected to formal meta-analysis. CONCLUSIONS: No overwhelming clinical evidence has been presented to establish the existence of a TRIM effect that relates allogeneic blood transfusion to postoperative infection.

Blood Transfusion, Autologous↗

PubMed2005

Fluorescence in situ hybridization and chromosome studies after transfusion in newborns: is a waiting period necessary?

BACKGROUND: Delaying chromosome studies after transfusion is common practice in many neonatal intensive care units (NICUs). Yet, no evidence exists to support this practice. PURPOSE: To investigate the effects of filtration and irradiation on chromosome detection, and to evaluate donor chromosome interference after transfusion. METHODS: Packed red blood cells (PRBCs) were evaluated by fluorescence in situ hybridization (FISH) and chromosome analyses. To evaluate donor leukocyte survival, blood was collected from female neonates who received male-donated PRBCs. RESULTS: Irradiated, leukodepleted blood had no Y chromosome detection by FISH. Irradiated, microaggregate filtered blood had Y chromosome detection in all samples by FISH but no metaphase growth. No donor chromosomes were detected in neonates after transfusion. CONCLUSIONS: Delaying chromosome or FISH analysis in transfused neonates who have received irradiated blood is unnecessary.

Chromosomes, Human, X↗

PubMedDate not supplied

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.

Aged↗

PubMed2005

Poststorage leuko-depleted plasma inhibits T-cell proliferation and Th1 response in vitro: characterization of TGFbeta-1 as an important immunomodulatory component in stored blood.

BACKGROUND: Poststorage, leuko-depleted blood transfusions have been associated with increased postoperative infections and improved allograft survival compared with prestorage leukocyte-depleted blood transfusion. Although the mechanism of this phenomenon remains to be fully elucidated, it is clear that the immunomodulatory effect is mediated by leukocytes/platelets or their products. METHOD: The aim of this study was to investigate the in vitro effects of pre- and poststorage leuko-depleted plasma (LDP) and buffy coat LDP on T-cell proliferation and cytokine synthesis using multiparameter flow cytometry. RESULTS: In cell cultures exposed to prestorage LDP and buffy coat LDP there were no significant changes compared with fresh blood. In cell cultures exposed to poststorage LDP, T-cells showed reduced expression of CD69, CD25 (IL-2Ralpha), CD122 (IL-2Rbeta) and CD132 (IL-2Rtau) and production of TNF-alpha and IL-2 but there was no significant alteration for IFN-tau or IL-4. Changes in cytokine/cytokine receptor synthesis and T-cell proliferation were shown to be directly proportional to poststorage LDP concentration. Some of these changes were characteristic of TGFbeta-1. Addition of TGFbeta-1 neutralising antibody to poststorage LDP, negated the immunosuppressive effect on PHA-stimulated PBMC cultures. CONCLUSIONS: The decrease in T-cell proliferation and Th1 cytokines TNF-alpha and IL-2, may be one basis of altered immunoregulation resulting in increased rates of certain types of infections and increased graft tolerance reported in patients receiving poststorage LD blood transfusions. TGFbeta-1 is a major immunomodulatory component of poststorage LD blood transfusions.

Apoptosis↗

PubMed2004

Development of white blood cell fragments, during the preparation and storage of platelet concentrates, as measured by using real-time polymerase chain reaction.

BACKGROUND AND OBJECTIVES: White blood cell (WBC) fragments may cause human leucocyte antigen (HLA) immunization in recipients. We investigated the occurrence and production of WBC fragments in platelet concentrates (PCs) and plasma units, during storage and filtration, by using real-time polymerase chain reaction (PCR) and flow cytometry. MATERIALS AND METHODS: To study the occurrence of WBC fragments, 'male' WBCs were spiked into double-filtered 'female' PCs in a concentration series of 0.03-100 WBCs/microl (n = 4 per level). To study the production of WBC fragments, 'male' WBCs were spiked into 'female' plasma units to 4 x 10(9) WBCs/l and stored at room temperature prior to filtration (n = 4 per storage time; t = 0, 24 or 48 h). DNA was measured by both albumin real-time PCR and Y real-time PCR. Intact WBCs were counted by using flow cytometry. The number of WBC fragments was calculated by subtracting cell-free DNA (real-time PCR on supernatant) and intact WBCs (flow cytometry) from the total DNA amount (real-time PCR). RESULTS: Spiking of 'male' WBCs into 'female' PCs showed that the Y real-time PCR is linear and has a reproducible quantitative range down to 0.03 WBC/microl, but that the albumin-PCR, in unspiked samples, revealed a total of 6-10 WBC equivalents/microl (eq/microl). After centrifugation, half of this was observed as cell-free DNA in the supernatant, suggesting that the remaining DNA is derived from WBC fragments. The number of intact WBCs, amount of cell-free DNA and number of WBC fragments after filtration increased significantly when filtration was delayed for up to 48 h, from 0.1 WBC/microl, 1.3 WBC eq/microl and 0.6 WBC eq/microl at t = 0 h to 25 WBC/microl, 38 WBC eq/microl and 57 WBC eq/microl at t = 48 h, respectively. CONCLUSIONS: WBC fragments occur in WBC-reduced PCs and increase when products are stored, prior to filtration, up to levels that are equivalent to the amounts of intact WBCs that induce HLA immunization (i.e. > 5 x 10(6)/unit).

Blood Preservation↗

PubMed2006

Whole-blood leukoreduction filters are a source for cryopreserved cells for phenotypic and functional investigations on peripheral blood lymphocytes.

BACKGROUND: Leukoreduction of blood is now widely performed by blood banks, and the possibility of recovering 10(8) to 10(9) white blood cells (WBCs) from leukoreduction filters, which are usually discarded, represents a promising source for normal human cells. Previous studies with these filters to prepare WBCs have performed their experimentation with fresh cells only. Whether these filter-derived cells could also be used to prepare frozen cell banks to facilitate work organization and open new avenues for their utilization as references in physiological studies and clinical investigations was investigated. STUDY DESIGN AND METHODS: Blood samples or whole-blood leukoreduction filters were obtained, after informed consent, from volunteers or blood donors, respectively. The proportions of CD3+, CD14+, CD16+, CD19+, and CD45+ cells within peripheral blood mononuclear cells (PBMNCs) were determined by flow cytometry from all samples. B cells were isolated and their functional responses were evaluated in vitro. RESULTS: The yield of PBMNCs recovered from whole-blood leukoreduction filters was lower (50%) than the one with fresh blood samples but still provided 2 x 10(8) to 4 x 10(8) PBMNCs per unit. After one cycle of freezing-thawing, the proportions of B- and T-cell populations were similar to normal blood values. Purified B cells issued from whole-blood leukoreduction filters displayed normal phenotypes and functions. CONCLUSION: Leukoreduction filters represent a valuable source of PBMNCs. These cells could be easily recovered to prepare frozen cell banks useful in basic phenotypic and functional analyses involving the main subsets of B cells and the global T-cell population.

Antigens, CD↗

PubMed2006

The effect of whole-blood storage time on the number of white cells and platelets in whole blood and in white cell-reduced red cells.

BACKGROUND: Whole blood (WB) can be stored for some time before it is processed into components. After introduction of universal white cell (WBC) reduction, it was observed that longer WB storage was associated with more residual WBCs in the WBC-reduced red cells (RBCs). Also, weak propidium iodide (PI)-positive events were observed in the flow cytometric WBC counting method, presumably WBC fragments. The effect of storage time on the composition of WB and subsequently prepared WBC-reduced RBCs was studied. STUDY DESIGN AND METHODS: WB was collected in bottom-and-top collection systems with inline filters, obtained from Baxter, Fresenius, or MacoPharma. Units were stored at room temperature and separated into components in 4-hour intervals between 4 and 24 hours after collection. RBCs were WBC-reduced by inline filtration (approx. 50/group). RESULTS: Platelet (PLT) counts were lower in WB stored for 4 to 8 hours compared to 20 to 24 hours (mean +/- SD): 79 +/- 31 versus 102 +/- 30 for Baxter (p < 0.01); 91 +/- 31 versus 101 +/- 35 for Fresenius (not significant); and 73 +/- 47 versus 97 +/- 31 (all x 10(9) per unit) for MacoPharma (p < 0.01), respectively. The median residual WBC counts in WBC-reduced RBCs for WB stored for 4 to 8 and 20 to 24 hours were 0.03 versus 0.17 for Baxter (p < 0.001), 0.00 versus 0.06 for Fresenius (p < 0.001), and 0.13 versus 0.26 (all x 10(6) per unit) for MacoPharma (not significant), respectively. All WBC-reduced RBCs contained fewer than 5 x 10(6) WBCs per unit. A longer storage time of WB was associated with more weak PI-positive events, irrespective of the filter. CONCLUSION: Longer storage of WB before processing results in counting higher numbers of PLTs in WB, higher numbers of WBCs in WBC-reduced RBCs, and more weak PI-positive events.

Blood Donors↗

PubMed2006

Characterization of blood components prepared from whole-blood donations after a 24-hour hold with the platelet-rich plasma method.

BACKGROUND: The preparation of platelet (PLT) concentrates (PCs) from PLT-rich plasma (PRP) requires that whole blood (WB) be processed within 8 hours of collection. Increasing WB storage time to 24 hours would be logistically attractive. This study compares the in vitro quality of blood components prepared from WB stored for 8 and 24 hours at room temperature before processing with the PRP method. STUDY DESIGN AND METHODS: WB units were collected from ABO-matched blood donors. To reduce individual variations, paired donations were drawn in parallel, pooled, and split back in the collection bag. One unit was held for 6 to 8 hours and the other for 22 to 24 hours at 20 to 24 degrees C. Prestorage leukoreduced components were prepared with the PRP as intermediate product and analyzed during storage. RESULTS: RBC units prepared after an 8- or 24-hour hold were comparable in terms of hemolysis, sodium, pH, and ATP levels. RBC 2,3- diphosphoglycerate (2,3-DPG) was significantly lower in RBCs prepared from 24-hour hold donations immediately after processing but not after 20 days of storage. Residual white blood cells were approximately fivefold higher (p < 0.05) in 24-hour RBC units. For PCs, measurements for glucose, ATP, lactate, pH, extent of shape change, hypotonic shock response, and CD62p activation were similar. No differences were observed in the von Willebrand factor, factor (F)V, FVIII, and fibrinogen content of fresh-frozen plasma. CONCLUSIONS: The decrease in FVIII and RBC 2,3-DPG can be acceptable as a compromise to improve blood component logistics, but leukoreduction efficiency must be improved before considering the adoption of an overnight storage of WB before PRP processing.

ABO Blood-Group System↗

PubMed2006

Mirasol PRT treatment of donor white blood cells prevents the development of xenogeneic graft-versus-host disease in Rag2-/-gamma c-/- double knockout mice.

BACKGROUND: Mirasol PRT (Navigant Biotechnologies) treatment utilizes exposure to light in the presence of riboflavin to introduce irreparable lesions to nucleic acids thereby inhibiting pathogen and WBC replication. The ability of Mirasol PRT-treated mononuclear cells (MNCs) to generate xenogeneic graft-versus-host disease (GVHD) responses was used to model transfusion-associated GVHD (TAGVHD). STUDY DESIGN AND METHODS: Pairs of human MNCs from five different individual donors that had or had not received Mirasol PRT treatment and contained 30 x 10(6) CD3+ cells were injected intraperitoneally into sublethally irradiated (350 cGy) Rag2(-/-)gamma c(-/-) double-knockout mice. Recipient mice were weighed and observed regularly and euthanized when they exhibited symptoms of GVHD or at termination of the experiment. Recipient lymphoid compartments were collected and phenotyped for the presence of human lymphoid cells. The presence of human cytokines and/or immunoglobulins in the recipient plasma was also used to detect the presence of human cells. RESULTS: Twelve of 14 mice injected with untreated cells developed xenogeneic GVHD, whereas 0 of 14 mice injected with Mirasol PRT-treated cells developed xenogeneic GVHD. End-stage xenogeneic GVHD in the recipients of untreated cells was characterized by the presence of splenic human cytolytic CD4+ and CD8+ cells, with high levels of interferon-gamma, interleukin-10, and xenoreactive antibodies in the plasma. CONCLUSION: Mirasol PRT treatment of the donor MNCs abolished xenogeneic GVHD responses, indicating that the use of Mirasol PRT treatment of blood products should prevent the development of TAGVHD.

Animals↗

PubMed2006

A novel source of viable peripheral blood mononuclear cells from leukoreduction system chambers.

BACKGROUND: Buffy coats are becoming less available as a source of research-grade peripheral blood mononuclear cells (PBMNCs). Therefore, alternative sources of these cells were investigated. STUDY DESIGN AND METHODS: PBMNCs isolated from the cells retained in leukoreduction system chambers (LRSCs) and those eluted from white blood cell filters were compared. From LRSCs (1.88 +/- 0.40) x 10(9) PBMNCs (n = 13) versus (0.43 +/- 0.15) x 10(9) PBMNCs were isolated from leukofilter eluates (LFEs, n = 8; p < 0.0001). RESULTS: Cells from LRSCs and LFEs produced similar numbers of burst-forming unit-erythroid, colony-forming unit (CFU)-granulocyte-macrophage, and CFU-granulocyte-erythrocyte-monocyte-macrophage-megakaryocyte colonies. The percentages of cells positive for CD3, CD4, CD8, CD14, CD19, and CD56 in the PBMNCs isolated from LRSCs and LFEs were indistinguishable. Cells isolated from LRSCs expressed higher levels of CD69 and CD25 in reaction to staphylococcal enterotoxin B than the cells isolated from LFEs. The source of cells affected neither the yield and purity of immunomagnetically isolated CD3+ cells, CD14+ cells, and CD56+ cells nor the function of T cells, natural killer cells, and in vitro matured dendritic cells (DCs). DC yield from LRSC-derived CD14+ cells, however, was higher. CONCLUSION: LRSCs are a novel source of fully functional PBMNCs that can replace the more traditional sources of research-grade cellular products.

Dendritic Cells↗

PubMed2005

Depletion of resident Chlamydia pneumoniae through leukoreduction by filtration of blood for transfusion.

Current studies indicate that a significant percentage of healthy blood donors carry Chlamydia pneumoniae in their blood. Although the clinical significance of such findings is unknown, eradication of such bacteria from blood components may contribute to transfusion safety. Deletion of C. pneumoniae in Red Blood Cell (RBC) units was accomplished through leukoreduction by filtration. The presence of bacteria in RBC units before and after leukoreduction was assessed by real-time PCR using primers specific for C. pneumoniae 16S rRNA. The eluates of filters used for leukoreduction were also assessed by PCR and immunostaining with fluorescein isothiocyanate-conjugated chlamydial monoclonal antibodies specific for C. pneumoniae determination. Nineteen of 30 RBC units tested showed the presence of C. pneumoniae DNA. Leukofiltration resulted in a marked reduction of leukocytes as well as C. pneumoniae in terms of bacterial number and positive rate for the bacteria. The eluates of filters showed trapped bacteria determined by both PCR and immunostaining assays. Thus, leukoreduction with a filter is an effective method to significantly reduce resident C. pneumoniae levels in RBC components but may not be completely sufficient for total eradication of this pathogen.

Adult↗

PubMed2005

Anemia, allogenic blood transfusion, and immunomodulation in the critically ill.

Anemia and allogenic RBC transfusions are exceedingly common among critically ill patients. Multiple pathologic mechanisms contribute to the genesis of anemia in these patients. Emerging risks associated with allogenic RBC transfusions including the transmission of newer infectious agents and immune modulation predisposing the patient to infections requires reevaluation of current transfusion strategies. Recent data have suggested that a restrictive transfusion practice is associated with reduced morbidity and mortality during critical illness, with the possible exception of acute coronary syndromes. In this article, we review the immune-modulatory role of allogenic RBC transfusions in critically ill patients.

Anemia↗