Leucocyte-depleted Blood Research Articles

Ex vivo normothermic perfusion of isolated segmental porcine bowel: a novel functional model of the small intestine.

BackgroundThere is an unmet need for suitable ex vivo large animal models in experimental gastroenterology and intestinal transplantation. This study details a reliable and effective technique for ex vivo normothermic perfusion (EVNP) of segmental porcine small intestine.MethodsSegments of small intestine, 1.5–3.0 m in length, were retrieved from terminally anaesthetized pigs. After a period of cold ischaemia, EVNP was performed for 2 h at 37°C with a mean pressure of 80 mmHg using oxygenated autologous blood diluted with Ringer’s solution. The duration of EVNP was extended to 4 h for a second set of experiments in which two segments of proximal to mid-ileum (1.5–3.0 m) were retrieved from each animal and reperfused with whole blood (control) or leucocyte-depleted blood to examine the impact of leucocyte depletion on reperfusion injury.ResultsAfter a mean cold ischaemia time of 5 h and 20 min, EVNP was performed in an initial group of four pigs. In the second set of experiments, five pigs were used in each group. In all experiments bowel segments were well perfused and exhibited peristalsis during EVNP. Venous glucose levels significantly increased following luminal glucose stimulation (mean(s.e.m.) basal level 1.8(0.6) mmol/l versus peak 15.5(5.8) mmol/l; P < 0.001) and glucagon-like peptide 1 (GLP-1) levels increased in all experiments, demonstrating intact absorptive and secretory intestinal functions. There were no significant differences between control and leucocyte-depleted animals regarding blood flow, venous glucose, GLP-1 levels or histopathology at the end of 4 h of EVNP.ConclusionsThis novel model is suitable for the investigation of gastrointestinal physiology, pathology and ischaemia reperfusion injury, along with evaluation of potential therapeutic interventions.

Comparative Study for Measurement of Residual Leucocytes in Leucodepleted Red Blood Cells by Two Different Methods.

Estimation of residual leukocytes in blood components after leukodepletion is crucial for assessment of quality. Flow cytometry (FC) and Nageotte hemocytometer are the most widely accepted methods for counting residual white blood cells (rWBCs) in leucocyte-depleted (LD) blood components. The objective of this study was to compare use of Nageotte counting chamber and FC for quality control of leukodepleted red cell units. A prospective, observational study was conducted in the department of Transfusion Medicine. A total of 80 whole blood donations from healthy donors were subjected to testing by FC and Nageotte hemocytometer for estimation of rWBC in duplicate. Additionally, ten personnel attempted a survey for ease of use of FC. Number of rWBC detected by flow cytometer were between 1 WBC/μL and 28 WBCs/μL whereas that detected by Nageotte's chamber were between 0 WBC/μL (lowest) and 5 WBCs/μL. Coefficient of variation was found to be 87.36% by Nageotte hemocytometer method and 43.26% by FC. Linear regression analysis did not show any correlation (R-squared = 0.01, p = 0.13) between the two methods which signifies that the two methods cannot be used interchangeably. Pearson's correlation coefficient showed a weak relation between results obtained by the two methods. Inter-observer variation was found to be significant with use of Nageotte hemocytometry. Survey for ease of use of FC indicated acceptability of FC with favorable scores. Flow cytometric technique provides a reproducible and objective tool for counting rWBC in leukodepleted blood components compared with the Nageotte hemocytometer.

A fast and cost-effective microsampling protocol incorporating reduced animal usage for time-series transcriptomics in rodent malaria parasites

BackgroundThe transcriptional regulation that occurs in malaria parasites during the erythrocytic stages of infection can be studied in vivo with rodent malaria parasites propagated in mice. Time-series transcriptome profiling commonly involves the euthanasia of groups of mice at specific time points followed by the extraction of parasite RNA from whole blood samples. Current methodologies for parasite RNA extraction involve several steps and when multiple time points are profiled, these protocols are laborious, time-consuming, and require the euthanization of large cohorts of mice.ResultsA simplified protocol has been designed for parasite RNA extraction from blood volumes as low as 20 μL (microsamples), serially bled from mice via tail snips and directly lysed with TRIzol reagent. Gene expression data derived from microsampling using RNA-seq were closely matched to those derived from larger volumes of leucocyte-depleted and saponin-treated blood obtained from euthanized mice with high reproducibility between biological replicates. Transcriptome profiling of microsamples taken at different time points during the intra-erythrocytic developmental cycle of the rodent malaria parasite Plasmodium vinckei revealed the transcriptional cascade commonly observed in malaria parasites.ConclusionsMicrosampling is a quick, robust and cost-efficient approach to sample collection for in vivo time-series transcriptomic studies in rodent malaria parasites.

Treatment of inherited platelet disorders

For patients affected by severe inherited platelet dysfunctions, e.g. Glanzmann thrombasthenia (GT) or Bernard-Soulier syndrome (BSS), platelet transfusion is frequently needed for controlling spontaneous bleeding, and is always needed when trauma occurs or surgery is performed. For the mild-to-moderate bleeding entities, e.g. storage pool disease, thrombaxane A2 receptor defect, platelet transfusion is usually unnecessary. Transfusion of platelets should be used selectively and sparingly because of the substantial risk of alloimmunization against HLA antigens and/or platelet glycoproteins (GP) αIIb, β(3), or αIIbβ(3) in GT, and GPI-IX-V in BSS, which may lead to refractoriness to therapy. To reduce the risk, HLA-matched single donors of platelets should be used. If such donors are unavailable, leucocyte-depleted blood components should be used. Therapy other than platelet transfusion includes: (i) Prevention (vaccination against hepatitis B, avoidance of non-steroidal anti-inflammatory drugs, preservation of dental hygiene, correction of iron deficiency and prenatal diagnosis). (ii) Topical measures (compression with gauze soaked with tranexamic acid, fibrin sealants, splints for dental extractions and packing for nose bleeds). (iii) Antifibrinolytic agents that are useful for minor surgery and as adjuncts for other treatment modalities. (iv) Desmopressin that increases plasma levels of von Willebrand factor and factor VIII giving rise to increased platelet adhesiveness and aggregation associated with shortened bleeding time. (v) Recombinant factor VIIa (rFVIIa). GT patients have been treated for bleeding episodes by rFVIIa with partial success. The mechanism by which rFVIIa arrests bleeding is probably related to increased thrombin generation by a tissue factor-independent process, enhanced platelet adhesion and restoration of platelet aggregation. (vi) Female hormones. Excessive bleeding during menarche in patients with GT or BSS can be controlled by high doses of oestrogen followed by high doses of oral oestrogen-progestin. Menorrhagia later in life can be managed by continuous oral contraceptives. Depo-medroxyprogesterone acetate administered every 3 months is an alternative when combined oral contraceptives are contraindicated.

Le risque infectieux viral chez le polytransfusé : séroprévalence de sept agents viraux dans le centre tunisien

The aim of this study is to evaluate the prevalence of seven transfusion-transmitted viruses in polytransfused adults and children comparatively with a group of healthy control subjects. We studied 107 polytransfused patients (59 adults and 48 children) and 160 control subjects (100 blood donors and 60 children). Immunoenzymatic tests were used for detection of HBs antigen (HBs Ag), antibodies against hepatitis C Virus (anti-HCV), and human immunodeficiency virus (anti-HIV), and IgG antibodies against human cytomegalovirus (IgG anti-CMV), human parvovirus B19 (IgG anti-PB19), and hepatitis E virus (IgG anti-HEV). An immunofluorescent assay was performed for the detection of human herpesvirus 8 antibodies (anti-HHV8). Prevalence of HBs Ag, anti-HCV, anti-HIV, IgG anti-CMV, IgG anti-PB19, IgG anti-HEV, and anti-HHV8 in polytransfused group was 8.4, 4.7, 0, 86.9, 60.7, 28.9, and 47.6%, respectively, and 1.8, 0.6, 0, 86.2, 53.1, 10, and 12.5%, respectively, in the control group. The difference in prevalence between the two groups was statistically significant for HBs Ag (P = 0.01), anti-HCV (P = 0.03), IgG anti-HEV (P < 10(-4)), and IgG anti-HHV8 (P < 10(-4)). Categorization according to age showed that hepatitis B and C risk was limited in adult polytransfused group. HHV8 infection was higher in polytransfused subjects born before the use of leucocyte-depleted blood components. Our results corroborate literature data on the risk of HEV and HHV8 infection by blood transfusion. Hepatitis B vaccination and improvement in screening tests have an important role in reduction of hepatitis B and C risk in transfusion, especially in young polytransfused persons. However, a residual risk of transmitting viral infections persists, and efforts are needed to improve transfusion safety.

Leucocyte-Depleted Blood Transfusion is an Independent Predictor of Surgical Morbidity in Patients Undergoing Elective Colon Cancer Surgery—A Single-Center Analysis of 531 Patients

Leukocyte-depleted packed red blood cells (PRBC) were introduced to reduce potential immunomodulatory effects and transfusion-associated morbidity. It has, however, remained unclear, if leucocyte depletion prevents negative side effects of blood transfusion. The aim of this analysis was to examine the effects of leukocyte-depleted PRBC on surgical morbidity after elective colon cancer surgery. Data were prospectively collected from 531 consecutive patients undergoing elective colon cancer surgery at a single high-volume center (University Hospital) from 2002 to 2008. Potentially predictive factors for surgical morbidity were tested on univariate and multivariate analysis. A total of 531 patients with colon cancer were included. A curative (R0) resection was performed in 497 patients (94%). The mortality rate, overall morbidity rate, and surgical morbidity rate were 1.1, 33, and 21%, respectively. Some 135 patients (25%) received perioperative transfusion of PRBCs. On multivariate analysis age (odds ratio [OR] 1.04, 95% confidence interval [95% CI] 1.02-1.06; P = 0.001), BMI (OR 1.08, 95% CI 1.03-1.13; P = 0.003), and PRBC transfusion (2.4, 1.41-4.11; P = 0.001) were revealed as independent predictors of surgical morbidity. The risk of surgical complications increased continuously with the amount of transfused PRBCs. The adverse impact of PRBC transfusion was neither restricted to the timepoint of transfusion (intraoperative or postoperative), nor to the kind of complication (infectious vs noninfectious complication). Perioperative transfusion of leukocyte-depleted PRBCs has a significantly negative effect on surgical morbidity of patients undergoing elective colon cancer surgery. The use of perioperative blood transfusions in these patients should be avoided, whenever possible.

Should irradiated blood products be given routinely to all patients with aplastic anaemia undergoing immunosuppressive therapy with antithymocyte globulin (ATG)? A survey from the European Group for Blood and Marrow Transplantation Severe Aplastic Anaemia Working Party

Should irradiated blood products be given routinely to all patients with aplastic anaemia undergoing immunosuppressive therapy with antithymocyte globulin (ATG)? A survey from the European Group for Blood and Marrow Transplantation Severe Aplastic Anaemia Working Party

Oral abstracts

A most memorable scene in ‘‘Bram Stoker’s Dracula’’of Francis Ford Coppola sees Count Vlad II of Wallachia procl Aim: ‘‘The blood is the life!’’It is impossible to evaluate how much the Irish novelist, writer of the 1897 book the film was based upon, was influenced by the developments in blood transfusion that characterized the end of the 19th and the beginning of the 20th century, but the word ‘‘transfusion’’ figures prominently in his manuscript. Past centuries had been characterized by successful blood transfusions between animals, but success in human transfusions had been limited prior to Landsteiner’s discovery of the red blood cell (RBC) membrane ABO antigens (1901) that permitted the establishment of safe blood transfusions. The application of refrigeration and anticoagulants to blood storage in the 1910s then paved the way to blood banking. Since those early days, developments in the RBC field have been tightly associated with technologies that changed science, allowing researchers to home into the detail, and had a huge impact on the quality of life. Today, proteomics technologies can be used to tackle important but neglected aspects of transfusion medicine, such as determining changes at the peptide and protein level during storage of blood products. Studies have demonstrated that stored leucocyte-undepleted whole RBC populations release over hundred proteins compared to the few released by leucocyte-depleted blood units. The leucocyte-poor RBC predominantly released carbonic anhydrase and thioredoxin peroxidase B. The presence of oxygen, in this context, gives rise to extensive RBC surface modifications, which can be prevented by adding protease inhibitors. Proteins released during storage of leucocyte-depleted RBCs were found in form of microvesicles and nanovesicles enriched not only in integral membrane proteins, but specifically in oligomerized band 3, suggesting a preferential release of damaged cell components from otherwise functional RBCs. Flow cytometry was used in combination with proteomics to study storage of younger versus older RBCs. In leucocyte-depleted RBC stored for 42 days, phosphatidylserine exposure at the RBC membrane external surface did not increase and none of the surface markers studied decreased significantly, while the copy numbers of CD44, CD58, CD147 and glycophorin decreased and annexin release increased in RBC stored with leucocytes. A recent review summarizes the contribution of proteomics to transfusion medicine and puts forward a possible approach in form of a workflow for monitoring the quality of blood-based therapeutics by proteomics. This monitoring may be essential as more detailed analyses using state of the art mass spectrometry tools are likely to provide an even better insight into storage and environment-induced changes in the RBC that may be critical to optimize the quality of transfused RBC. Increasing our knowledge of the RBC protein make-up (low abundant proteins in particular); of their changes in health and disease and in the interplay with other blood cells/endothelial cells will also be beneficial in assessing changes in their quality, while the study of intra-species differences will be instrumental in the light of the passage from animal experimentation to clinical trials.

Leucocyte depletion of perioperative blood transfusion does not affect long-term survival and recurrence in patients with gastrointestinal cancer

Perioperative red blood cell (RBC) transfusion may be associated with a poor prognosis in cancer surgery. Allogeneic leucocytes are assumed to play a causal role. This study evaluated the long-term effect of transfusion with leucocyte-depleted (LD) blood in patients with gastrointestinal cancer. The Transfusion Associated Complications = Transfusion Induced Complications? (TACTIC) study is a multicentre randomized controlled trial evaluating the short-term benefits of LD versus non-LD RBC transfusions. The present study evaluated 5-year survival and cancer recurrence among 512 patients with gastrointestinal cancer included in the TACTIC study. Some 89.2 per cent of patients had a primary tumour and 79.7 per cent underwent surgery with curative intent; 243 patients received perioperative RBC transfusion (median 3 units). The 5-year overall survival rate of patients with any type of gastrointestinal cancer was 50.8 per cent in the LD group and 45.8 per cent in the non-LD group (P = 0.191). Corresponding 5-year disease-free survival rates were 60.0 and 56.6 per cent (P = 0.482), and recurrence rates 32.9 and 34.3 per cent (P = 0.864). Leucocyte depletion is not associated with better long-term survival and lower recurrence rates in patients with gastrointestinal cancer.

Leucocyte depletion improves renal function during reperfusion using an experimental isolated haemoperfused organ preservation system

Leucocytes have been implicated as mediators of renal ischaemia-reperfusion injury. This study aimed to demonstrate the effect of white cells in early renal reperfusion injury using an isolated haemoperfused porcine kidney model. After 2 h cold storage, porcine kidneys were perfused with normothermic autologous blood using an isolated organ preservation system. This was designed using cardiopulmonary bypass technology, and perfusion commenced with a circulating serum creatinine level of 1000 micromol/l. In group 1 (n = 6) a leucocyte filter was included in the circuit and in group 2 (n = 6) non-filtered blood was used. The mean(s.d.) area under the curve for serum creatinine was lower in the leucocyte-depleted experiments (1286(214) versus 2627(418); P = 0.002). Leucocyte depletion also led to improved urine output (191(75) versus 70(32) ml/h; P = 0.002) and higher creatinine clearance (10.6(2.8) versus 1.9(1.0) ml/min; P = 0.002). Renal blood flow, oxygen consumption and acid-base homeostasis were all improved by perfusion with leucocyte-depleted blood, and histological tubular damage was ameliorated. These data show that the depletion of leucocytes from blood used to perfuse porcine kidneys improved postschaemic renal function, indicating that white cells play an important role in renal ischaemia-reperfusion injury.

Long-term survival after colorectal surgery associated with buffy-coat-poor and leucocyte-depleted blood transfusion: a follow-up study

<h2>Summary</h2> A Danish clinical trial showed that transfusion with leucocyte-depleted red blood cells reduces postoperative infectious complications compared with cells without buffy-coat. However, the effect on long-term outcome is unknown. We followed up the 142 cancer patients transfused with buffy-coat-poor red cells, the 118 transfused with leucocyte-depleted blood, and the 329 who were not transfused, until 2003. After 7 years' follow-up, survival for those with leucocyte-depleted blood transfusion (46 [41%]) was not significantly different from transfusion of blood without buffy-coat (59 [45%], p=0·51). Although survival is reduced by blood transfusion, it does not differ between the two transfusion regimens.

Long-term survival after colorectal surgery associated with buffy-coat-poor and leucocyte-depleted blood transfusion: a follow-up study

A Danish clinical trial showed that transfusion with leucocyte-depleted red blood cells reduces postoperative infectious complications compared with cells without buffy-coat. However, the effect on long-term outcome is unknown. We followed up the 142 cancer patients transfused with buffy-coat-poor red cells, the 118 transfused with leucocyte-depleted blood, and the 329 who were not transfused, until 2003. After 7 years' follow-up, survival for those with leucocyte-depleted blood transfusion (46 [41%]) was not significantly different from transfusion of blood without buffy-coat (59 [45%], p=0.51). Although survival is reduced by blood transfusion, it does not differ between the two transfusion regimens.

Controlled reperfusion with retrograde leucocyte-depleted blood cardioplegia improves initial graft function after heart transplantation- a clinical study

Objectives: Impaired myocardial contractility due to ischemic and reperfusion injury is a common problem after heart transplantation. We evaluated the efficiency of leucocyte-depleted blood cardioplegia (BCP) to improve initial graft function.

Risk Factors of Cytomegalovirus Infection in Autologous Stem Cell Transplantation (ASCT).

Aim: to analyse the incidence and risk factors of cytomegalovirus (CMV) infection after ASTC.Methods: 129 pts who underwent ASCT in our Institution from June 1997 to June 2004 were analysed retrospectively ( 40 NHL, 66 MM, 8 HD, 8AML, 7CLL). Conditioning regimen consisted in MitoMel in NHL, Melphalan in MM (100–200/m2) and BEAM in AML and CLL. All patients were monitored with Ag pp65 twice weekly from conditioning therapy to hematological recovery. CMV prophylaxis consisted of acyclovir (400 mg p.o. twice daily) and the use of leucocyte-depleted blood products. Following the report of a positive CMV Ag all patients were treated with ganciclovir 5 mg/kg or foscarnet 90 mg/kg twice daily for 2 weeks or until the test was negative.Results: we observed 8 CMV Ag positive: 5 were MM in RP at the transplant and 2 out of 3 NHL were heavily pretreated. Six patients were older than 60 years. The number of CD34 infused was 3.8x106/kg (range 3.1–5.1 ). The mean time for PMN > 500/ul and platelets > 30.000/ul was respectively 11 and 21 days. CMV Ag occurred after a mean time of 21 days (4–45) following ASCT. All patients with a positive CMV Ag were febrile. CMV infection was considered the sole cause of fever in 4 pts; 2 had antibiotic-resistant fever, 1 acute enteritis and 1 pneumonia. The remaining 4 pts had concomitant sepsis: Klebsiella, Pseudomonas, Streptococcus Pneumoniae and Staphylococcus Epidermidis. Seven pts had CMV Ag levels >5/200000 cells and one pt >2/200000 at presentation. The resolution of fever and clearance of CMV Ag occurred after 5.6 days (3–9) from the start of antiviral treatment, but in 2 pts was delayed (respectively 14 and 18 days). Of note, these two pts had the highest CMV Ag levels observed (350 and 961) and one treated with foscarnet developed acute renal failure.Conclusion:1.1) CMV infection is an infrequent complication of ASCT( 6,2%)2.2) CMV Ag detection was unrelated to the number of CD34 infused and the duration of neutropenia.3.3) Pts heavly pretreated, febrile or with sepsis had high rates of CMV reactivation and disease. This subset of pts require more frequent diagnostic evaluation and prompt antiviral therapy.

Prevention of blood-transfusion-induced impairment of anastomotic healing by leucocyte depletion in rats.

To find out what effect whole blood and leucocyte-depleted blood transfusions had on the healing process of intestinal anastomoses in rats. Experimental study. Teaching hospital, Greece. 100 Wistar rats in five groups of 20 each. Small and large bowel anastomoses were made and the five groups were given normal saline, homologous whole blood, heterologous whole blood obtained from PVG rats, homologous leucocyte-depleted blood or heterologous leucocytedepleted blood during the operation. Bursting pressures of anastomoses on the third and seventh postoperative days and infective complications. The groups given whole blood transfusions had significantly more anastomotic abscesses than controls (p = 0.003 compared with heterologous, p = 0.05 compared with homologous for the small bowel, and p = 0.007 for the large bowel). The pressure measurements indicated a significant reduction in anastomotic strength in the same groups compared with the control group (p = 0.0001/p = 0.001 on the third postoperative day, and p = 0.00001/p = 0.0004 on the seventh postoperative day for small and large bowel, respectively). There was no reduction in anastomotic strength in the leucocyte-depleted blood groups. Transfusion of leucocyte-depleted blood does not seem to impair intestinal anastomotic healing and carries an acceptable incidence of postoperative complications.

Prevention of worsening of severe thrombocytopenia after red cell transfusions by the use of leucocyte-depleted blood

Platelet counts were measured before and after red cell transfusions in 30 patients with anaemia and severe thrombocytopenia resulting from haematological diseases. There was a mean reduction of 1.1 x 109/l (P = 0.43) in the platelet count after transfusions of 2-3 units of leucocyte-depleted red cell concentrates (20 patients). However, there was a mean reduction of 2.7 x 109/l (P = 0.03), approximately 10%, in the platelet count after transfusions of non-leucocyte-depleted red cell concentrates (10 patients). The findings suggest that the forthcoming introduction of universal leucocyte depletion of red cell concentrates will minimize the worsening of thrombocytopenia that occurs in severely thrombocytopenic patients receiving standard non-leucocyte-depleted red cell concentrates.

Orthotopic transplantation of pig hearts harvested after 30 min of normothermic ischemia: controlled reperfusion with blood cardioplegia containing the Na+-H+-exchange inhibitor HOE 642.

The aim of our study was to develop a surgical technique for a successful transplantation of hearts harvested after 30 min of normothermic ischemia without donor pretreatment. Successful transplantation of ischemic compromised hearts could help to expand the severely limited donor pool. We used the pig model because this species is very susceptible to myocardial ischemia. Na+-H+-exchange (NHE) inhibitors have shown excellent protective properties in several in vitro and in vivo models of myocardial ischemia and reperfusion. In group I (n=12) hearts were harvested after 30 min of normothermic ischemia following cardiac arrest induced by exsanguination. Hearts were perfused with warm blood cardioplegia and transplanted orthotopically. In group II (n=9) controlled reperfusion with cold leucocyte-depleted blood cardioplegia was performed after 30 min of normothermic ischemia. In group III (n=8) the same procedure was performed as in group II but blood cardioplegia contained 1 mmol/l HOE 642. In group I massive myocardial oedema was observed and none of the animals could be weaned from cardiopulmonary bypass (CPB). In contrast, all animals in groups II and III could be weaned from CPB with low dose inotropic support. In groups II and III the contractility of the hearts, expressed as maximal left and right ventricular stroke work index was significantly impaired after transplantation as compared with the preoperative value. Supplementation of blood cardioplegia with HOE 642 resulted in a significantly better recovery of the LVSWImax (Group II vs. III). Successful transplantation of pig hearts is possible after 30 min of normothermic ischemia without donor pretreatment if a controlled reperfusion with cold leucocyte-depleted blood cardioplegia is performed. HOE 642 given during reperfusion only improves posttransplant left ventricular function.

Perioperative Allogeneic Blood Transfusion Does Not Cause Adverse Sequelae in Patients With Cancer: A Meta-Analysis of Unconfounded Studies

Background There is controversy over whether perioperative allogeneic red blood cell transfusions are associated with an increased risk of cancer recurrence, postoperative infection or death in patients with cancer undergoing surgery. Methods A systematic meta-analysis was performed to answer this question. Studies were identified from electronic databases (Medline 1966–1997, Cancerlit 1983–1997, Current Contents, Cinahl 1982–1996, Healthstar 1990–1997, Bioabstracts 1990–1996 and Embase), by hand search of the bibliographies of identified studies and relevant journals, and by contact with experts in the field. All randomized controlled trials or prospective cohort studies with active comparator controls (autologous or leucocyte-depleted allogeneic blood) were eligible for inclusion if they reported on mortality, infection or recurrence rate in patients with cancer undergoing potentially curative surgical resection. The validity of the identified studies was assessed by means of a standardized scale, and data abstraction was carried out by two investigators independently. A random effects model was used for data synthesis. Results Of the 2172 references identified, only 17 studies fulfilled the inclusion criteria. After exclusion of duplicate publications, six randomized controlled trials and two prospective cohort studies with appropriate concurrent controls were included in the analysis. The summary risk ratios were 0·95 (95 per cent confidence interval (c.i.) 0·79–1·15) for all-cause mortality and 1·06 (95 per cent c.i. 0·88–1·28) for cancer recurrence, the two endpoints that were appropriate to combine statistically. There was significant heterogeneity (explainable by differences in study design and patient characteristics) in the postoperative infection data and the summary risk ratio was 1·00 (95 per cent c.i. 0·76–1·32) for the four studies that were appropriate to subject to meta-analysis. Given the sample sizes of these eight studies, this meta-analysis had insufficient power to detect a relative difference of less than 20 per cent in the frequency of death, cancer recurrence or infection between the allogeneic and control transfusion arms. Conclusion Although more studies are required before a definitive statement can be made, at this time there is no evidence that allogeneic blood transfusion increases the risk of clinically important adverse sequelae in patients with cancer undergoing surgery. © 1998 British Journal of Surgery Society Ltd

Clinical evaluation of the new Pall leucocyte-depleting blood cardioplegia filter (BC1).

It is now widely acknowledged that autologous leucocytes are inappropriately activated during cardiopulmonary bypass (CPB). Removal of these activated leucocytes has been proposed as a clinical intervention. Several papers have recently reported benefits of systemic leucocyte depletion during CPB. There is also evidence that leucocyte-depleted blood cardioplegia is advantageous in the globally ischaemic human heart transplant setting. Recently, a new leucocyte-depleting filter for blood cardioplegia has been developed (Pall, BC1). In this paper, we report on the safety and efficiency of this device in the clinical situation. Fourteen patients undergoing routine cardiac surgery were recruited into this study. The BC1 blood cardioplegia filter was found to be an efficient leucocyte-depleting device, removing in excess of 70% (p = 0.001) of white blood cells, on average, from up to 5.3 litres of blood cardioplegia. The filter removed a small proportion of platelets (typically 11.3%), however, this was not statistically significant and no bleeding problems were encountered. Red cell removal was negligible and was not statistically significant, and no evidence of haemolysis was noted. The filter offered a very low resistance to flow with a mean pressure drop (deltaP) of 10.8 mmHg at a mean flow rate of 315 ml/min. We conclude that the Pall BC1 filter is a safe and efficient device for use with blood cardioplegia.

Pilot study of HLA alloimmunization after transfusion with pre-storage leucodepleted blood products in aplastic anaemia.

We have performed a pilot study to examine the incidence of alloimmunization using pre-storage leucocyte-depleted blood products (PLDP) in 16 previously transfused aplastic anaemia (AA) patients with no detectable HLA antibodies. A further eight AA patients with HLA antibodies received HLA-matched PLDP. Leucodepleted apheresed platelets were obtained using either Cobe spectra or Haemonetics system with an integral pall filter. Pall BPF4 filters were used for red cell preparation. Patients' sera were tested for HLA antibodies using lymphocytotoxicity (LCT). Patients who were HLA antibody negative by LCT at study entry were further tested with enzyme-linked immunoassay (ELISA). Out of 16 patients, two (12%) formed anti-HLA antibodies with a median follow-up of 9 months (range 1-15), but did not display platelet refractoriness to random donor platelets. Two patients were inadvertently transfused with non-leucodepleted blood products when later referred back to their local hospital. Both subsequently demonstrated HLA antibodies by LCT and became platelet refractory. These results contrast with a 50% incidence of HLA alloimmunization in a control group of AA patients transfused prior to this study with non-PLDP. HLA antibodies could no longer be detected by LCT in follow-up of three out of eight patients with HLA antibodies at study entry. Only one patient experienced non-haemolytic febrile transfusion reactions (NHFTR). We conclude that PLDP reduce the risk of alloimmunization even in previously transfused AA patients, PLDP are associated with a low incidence of NHFTR, and all new AA patients should receive PLDP from diagnosis.