Evaluation of concurrent collection of in-line filtered platelets and packed red blood cells by multicomponent apheresis with three last-generation apparatuses

BACKGROUND AND OBJECTIVES: Multicomponent apheresis enables the collection and procession of different blood products in a single donation. Different apparatuses vary in terms of principle and efficiency. Knowledge of them is essential to analyse cost effectiveness. MATERIALS AND METHODS: A total of 30 donors, well matched for baseline parameters, were randomly assigned to the concurrent collection of red blood cells (RBCs) and platelets (PLTs) with the Baxter Amicus (AM), the Haemonetics MCS plus (MCS+), and the Gambro Trima Accel (TA). The procedures were prospectively evaluated, focusing on yield, time, efficiency, citrate donor load and in vitro quality. RESULTS: PLT yield (x 10(11)/unit; mean +/- standard deviation) was 3.09 +/- 0.34 (AM), 2.53 +/- 0.35 (MCS+), 2.51 +/- 0.32 (TA). Absolute RBC mass (ml/unit; mean +/- standard deviation) was 177.4 +/- 2.7 (AM), 161.5 +/- 0.7 (MCS+), and 163.7 +/- 5.4 (TA). The programmed RBC collection target of 160-180 ml was reached by all instruments, whereas the programmed PLT yield of 3.0 x 10(11) was met satisfactorily by AM only. All units contained < 1 x 10(6) WBCs. In vitro RBC quality was equivalent among the systems. No significant differences were noted with collection efficiency, processed whole blood or citrate donor load. Owing to high collection and draw rates, the TA was the fastest of all the systems. The MCS+ had the longest donation/needle time and the highest PLT activation, but compensated with significantly lower draw and citrate infusion rates. The overall processing time was longest with the AM, as a result of manual procedures from donor disconnection to the final products. CONCLUSIONS: Multicomponent apheresis was performed safely and efficiently with all three instruments. There was no 'magic apparatus' as each system combined advantages and pitfalls for the diverse parameters evaluated.     

Collection of hyperconcentrated platelets with Trima Accel

BACKGROUND AND OBJECTIVES: Lowering the plasma content in single-donor platelet (PLT) concentrates well below 30% implies the need to collect platelets at very high concentrations. Trima Accel (TA) is validated for collection below 4000 x 10(3) PLTs/microl. We evaluated its performance at 5000 x 10(3) PLTs/microl. MATERIALS AND METHODS: Twenty blood donors underwent apheresis with TA twice collecting either a hyperconcentrated or a standard single-donor platelet concentrate with a target platelet concentration of 5000 or 1200 x 10(3) PLTs/microl, respectively. We analysed the collection efficiency, the collection rate and the quality of the collected by-plasma. RESULTS: We collected 20 hyperconcentrated and 20 standard units containing 2.56 +/- 0.5 and 3.39 +/- 0.4 x 10(11) PLTs at a concentration of 4518 +/- 978 and 1374 +/- 166 x 10(3) PLTs/microl in 45 +/- 8 and 39 +/- 6 min resulting in a collection efficiency of 47.5 +/- 10.0 and 70.7 +/- 7.9% and a collection rate of 5.9 +/- 1.4 and 8.8 +/- 1.5 x 10(9) PLTs/min, respectively (all results expressed as mean +/- standard deviation). The collected by-plasma showed a very high grade of cell purity and a satisfactory recovery of the clotting factors. CONCLUSION: Although TA is a suitable device for PLT collection at very high concentrations, improvements are desirable to further increase the productivity above its currently validated upper collect concentration limit.     

A multicentre evaluation of a new filtration protocol for leucocyte depletion of high-haematocrit red blood cells collected by an automated blood collection system

BACKGROUND AND OBJECTIVES: A multicentre trial was set up to evaluate the performance of a new leucodepletion protocol. MATERIALS AND METHODS: Filtration at high haematocrit was started during collection of red blood cell (RBC) products by apheresis with Trima. SAG-M was added after filtration through the filter. Haematocrits and haemoglobin of the filtered RBCs were measured. Residual leucocytes were determined by Nageotte counting. RESULTS: One-hundred and forty seven procedures were carried out. The haematocrit and haemoglobin contents were 57.3 +/- 3.0% and 55.1 +/- 4.3 g/unit, respectively. All products showed low residual leucocyte levels (< or = 0.75 x 106/unit; 99.31% < 1 x 106). CONCLUSION: Immediate, on-line, high-haematocrit filtration of red cells collected on Trima resulted in leucoreduced RBCs, which met the AABB and Council of Europe criteria.     

Hyperconcentrated platelets stored in additive solution: aspects on productivity and in vitro quality

BACKGROUND AND OBJECTIVES: New platelet (PLT) additive solutions (PASs) allow a plasma carryover of < 30% in PLT concentrates. This implicates the need to collect apheresis PLT concentrates at very high PLT concentrations: so-called dry PLTs (DPs). We used the TRIMA, with software version 4 (TRIMA V4), to collect such DPs and investigated the in vitro quality of these PLTs when stored in the new modified PAS-III (PAS-IIIM). MATERIALS AND METHODS: TRIMA V4 was programmed to collect 6.0 x 10(11) PLTs at a concentration of 5000 x 10(3) PLTs/microl. Two DPs were pooled, split into four equal parts and diluted to obtain secondary pools (SPs) consisting of 70% PAS-III/30% plasma, 70% PAS-IIIM/30% plasma, 80% PAS-IIIM/20% plasma or 100% plasma. In vitro testing was performed on days 0, 1, 5 and 7. Collection efficiency (CE), collection rate (CR) and PLT yield were calculated for each donation. RESULTS: Thirty-two runs with TRIMA V4 were performed, collecting 6.58 +/- 0.74 x 10(11) PLTs at a concentration of 4255 +/- 914 x 10(3)/microl in 99 +/- 19.9 min, resulting in a CE of 65.3 +/- 8.2% and a CR of 6.92 +/- 1.6 x 10(9) PLTs/min. On day 0, 34-37% of the PLTs in the units prepared for storage were already activated. PLTs stored in 70% or 80% PAS-IIIM showed superior in vitro quality compared to PLTs stored in PAS-III. CONCLUSIONS: TRIMA V4 is a suitable device for the collection of DPs. Nevertheless, improvements are desirable to further increase the ability to concentrate PLTs at very high levels. The storage of apheresis-derived PLTs in PAS III-M is a very promising approach, even at a plasma carryover of < 30%.     

Red blood cells metabolome changes upon treatment with different X-ray irradiation doses

The upholding of red blood cells (RBC) quality and the removal of leukocytes are two essential issues in transfusion therapy. Leukodepletion provides optimum results, nonetheless there are cases where irradiation is recommended for some groups of hematological patients such as the ones with chronic graft-vs-host disease, congenital cellular immunodeficiency, and hematopoietic stem cell transplant recipients. The European guidelines suggest irradiation doses from 25 to 50 Gray (Gγ). We evaluated the effect of different prescribed doses (15 to 50 Gγ) of X-ray irradiation on fresh leukodepleted RBCs bags using a novel protocol that provides a controlled irradiation. Biochemical assays integrated with RBCs metabolome profile, assessed by nuclear magnetic resonance spectroscopy, were performed on RBC units supernatant, during 14 days storage. Metabolome analysis evidenced a direct correlation between concentration increase of three metabolites, glycine, glutamine and creatine, and irradiation dose. Higher doses (35 and 50 Gγ) effect on RBC mean corpuscular volume, hemolysis, and ammonia concentration are considerable after 7 and 14 days of storage. Our data show that irradiation with 50 Gγ should be avoided and we suggest that 35 Gγ should be the upper limit. Moreover, we suggest for leukodepleted RBCs units the irradiation with the prescribed dose of 15 Gγ, value at center of bag, and ranging between 13.35–15 Gγ, measured over the entire bag volume, may guarantee the same benefits of a 25 Gγ dose assuring, in addition, a better quality of RBCs.     

Evolution of adverse changes in stored RBCs

Recent studies have underscored questions about the balance of risk and benefit of RBC transfusion. A better understanding of the nature and timing of molecular and functional changes in stored RBCs may provide strategies to improve the balance of benefit and risk of RBC transfusion. We analyzed changes occurring during RBC storage focusing on RBC deformability, RBC-dependent vasoregulatory function, and S-nitrosohemoglobin (SNO-Hb), through which hemoglobin (Hb) O(2) desaturation is coupled to regional increases in blood flow in vivo (hypoxic vasodilation). Five hundred ml of blood from each of 15 healthy volunteers was processed into leukofiltered, additive solution 3-exposed RBCs and stored at 1-6 degrees C according to AABB standards. Blood was subjected to 26 assays at 0, 3, 8, 24 and 96 h, and at 1, 2, 3, 4, and 6 weeks. RBC SNO-Hb decreased rapidly (1.2 x 10(-4) at 3 h vs. 6.5 x 10(-4) (fresh) mol S-nitrosothiol (SNO)/mol Hb tetramer (P = 0.032, mercuric-displaced photolysis-chemiluminescence assay), and remained low over the 42-day period. The decline was corroborated by using the carbon monoxide-saturated copper-cysteine assay [3.0 x 10(-5) at 3 h vs. 9.0 x 10(-5) (fresh) mol SNO/mol Hb]. In parallel, vasodilation by stored RBCs was significantly depressed. RBC deformability assayed at a physiological shear stress decreased gradually over the 42-day period (P < 0.001). Time courses vary for several storage-induced defects that might account for recent observations linking blood transfusion with adverse outcomes. Of clinical concern is that SNO levels, and their physiological correlate, RBC-dependent vasodilation, become depressed soon after collection, suggesting that even "fresh" blood may have developed adverse biological characteristics.     

Red blood cell regeneration induced by subcutaneous recombinant erythropoietin: iron-deficient erythropoiesis in iron-replete subjects [see comments]

Limited red blood cell (RBC) regeneration often prevents collection of sufficient blood from autologous donors. We studied the effects of subcutaneous recombinant erythropoietin (rEPO) in subjects making frequent blood donations. Six healthy iron-replete male subjects took rEPO (200 U/kg) subcutaneously daily, and donated blood (450 mL) twice a week for 3 weeks. During a control study, these subjects also attempted twice-weekly blood donations without rEPO. Four other males given rEPO, including one with idiopathic hemochromatosis, waited until day 8 to begin blood donations. All healthy subjects took oral ferrous sulfate. Subcutaneous rEPO given with blood donations resulted in a marked reticulocytosis (mean peak value 568 +/- 159 x 10(9)/L v 235 +/- 77 x 10(9)/L, control study; P < .05), and enhanced RBC production at 28 days (1,208 +/- 227 mL v 719 +/- 161 mL, P < .05). rEPO in advance of blood donations was slightly less effective in normal subjects (941 +/- 139 mL, P < .05); however, the subject with hemochromatosis produced substantially more RBCs (1,764 mL) than any normal subject. rEPO-treated normal subjects (but not the rEPO-treated patient with hemochromatosis or untreated controls) produced iron-deficient RBCs with elevated zinc protoporphyrin levels and low hemoglobin content. These cells appeared within 1 week of rEPO administration and before laboratory confirmation of depleted iron stores. Thus, subcutaneous rEPO is an effective stimulant of erythropoiesis in nonanemic blood donors. However, in addition to eventual depletion of iron stores, early functional iron deficiency affects response to the drug.     

Evaluation of in vivo and in vitro Quality of Apheresis-Collected RBC Stored for 42 Days

Background and Objectives : New technological developments make it possible to collect red blood cells (RBCs) by apheresis, which allows for better product consistency and has the potential for improved RBC quality. The purpose of these studies was to evaluate the quality and consistency of units of RBCs collected by apheresis using the MCS+® machine (Haemonetics Corp., Braintree, Mass., USA). Materials and Methods : Two studies were performed. In study 1 (n = 10), using containers and CP2D/AS-3 solutions from Medsep Corp. (Covina, Calif. USA), one-unit apheresis RBCs were compared to manually collected RBCs in a random crossover design. In study 2 (n = 12), 6 subjects had one unit collected, while the remaining 6 subjects had two units of RBCs collected with comparison to previously manually collected RBCs from the same donors. Haemonetics containers and solutions were used in study 2. Results : Low RBC volume variability was found for the apheresis collections with a standard deviation of only 6 ml difference between actual and target volumes. Combining the data from the two studies (n = 21 pairs), at 42 days of storage, the apheresis units showed slightly lower hemolysis (0.44±0.26 vs. 0.61±0.50%), lower supernatant potassium levels (50±3 vs. 53±3 mEq/l), and improved tolerance to osmotic shock (47±3 vs. 49±3%) as compared to manual units (p < 0.05). There was no statistically significant difference in RBC ATP (3.0±0.6 vs. 2.9±0.5 μmol/g Hb) or in 24-hour percent recoveries (81±6 for apheresis vs. 81±4% for apheresis red cells). Apheresis RBC quality was not affected by the manufacturer (Haemonetics vs. Medsep) of solutions and containers. Conclusions : RBC units collected by apheresis demonstrated low variability in volume of RBC mass collected, and showed similar RBC properties as compared to manually collected RBCs after processing and after 42 days of storage.     

Collection of Heparinized Plasma by Plasmapheresis

BACKGROUND AND OBJECTIVES: Heparinized plasma can be used for exchange transfusions in neonates and is usually collected by drawing whole blood using heparin as anticoagulant. The heparinized red blood cells and buffy coat cannot be used and are therefore discarded. To collect heparinized plasma more efficiently, a method was developed using an apheresis machine. MATERIALS AND METHODS: With an MCS3p apheresis machine (Haemonetics), plasma was collected from volunteer donors as anticoagulant, heparin in saline (30,000 IU/l) was added in a 1:9 ratio. The activated partial thromboplastin time (APTT) of the donors was measured before and immediately after the procedure, and various parameters were determined in the collected plasma. RESULTS: In 2 collection cycles, an average of 456+/-52 ml (mean +/- SD; n = 20) of heparinized plasma was collected, and 504+/-57 ml (n = 2; donors with a high hemoglobin level) when 3 cycles were performed. The leukocyte and platelet contamination in the plasma (n = 22) was 1.11+/-0.92x10(6) and 0. 05+/-0.22x10(9) per unit, respectively, which conformed to national specifications. Sodium levels were normal, but due to dilution of the plasma with heparin solution, potassium and calcium levels were about 20% lower than the serum levels in the donors. The donor APTT values were slightly longer after the procedure than before, but remained all within normal values. CONCLUSION: For the collection of heparinized plasma, apheresis has the advantage that (1) high-quality heparinized plasma can be harvested; (2) no blood components need to be discarded; (3) more plasma can be harvested with each donation, and (4) these procedures can be performed more often than whole blood donations.     

Quality of leucoreduced red blood cell concentrates: 5 years of follow-up in France

BACKGROUND: Since 1998, prestorage leucoreduction of all cellular blood components has been made mandatory in France. The French blood service needed to follow the data on the quality of the blood components prepared by blood centres. MATERIAL AND METHODS: Quality control (QC) data were submitted to a central data bank by each blood centre. The data were stratified by preparation method for analysis of key performance criteria - residual white blood cell (WBC) and total haemoglobin content. The red blood cell (RBC) preparation processes and the methods for measuring haemoglobin content and residual WBC count were those routinely employed by blood centres. Each year, more than 15,500 RBCs were tested. RESULTS: Red blood cells had a mean haemoglobin content between 53.6 and 54.9 g/unit depending on the year (2001 to 2005). The requirement of 40 g/unit was reached for about 99% of units. The haemoglobin content was influenced by the preparation process: 56.8 +/- 6.9 vs. 50.6 +/- 5.6 g/unit in average for whole blood filtration or RBC filtration, respectively. Apheresis RBCs exhibited a reduced variability (51.8 +/- 3.1 g/unit). The median residual WBC count remained low (0.046 to 0.057 x 10(6) WBCs/unit), and the percentage of RBC units exceeding the 1 x 10(6) WBCs/unit cut-off ranged from 1.5 to 0.6% depending on the year. A seasonal pattern was observed, with a significant increase (P < 0.001) of the median residual WBC count and of the percent of non-conforming units during the summer months. CONCLUSION: Our QC data suggest an overall compliance with the standard. Our data bank is useful to inform on the performance of leucoreduced RBC preparation processes carried out with market available devices.     

Rapid testing of red blood cells,white blood cells and platelets in intensive care patients using the HemoScreen™ point-of-care analyzer

Acute major bleeding is a condition that can be encountered in critically ill patients and may require rapid transfusions. To evaluate the need for packed red blood cells (RBCs) and platelets (PLTs), it is important to have rapid test results for RBC/hemoglobin and PLTs. Recently, PixCell Medical (Yokneam Ilit, Israel) introduced the HemoScreen?, an automated hematology analyzer. It is a point-of-care device that uses single sample cuvettes and image analysis of RBCs, PLTs and white blood cells (WBCs), performing a five-part differential count. The HemoScreen? is the first portable differential count instrument that uses image analysis. We compared the RBC, PLT, and WBC test results of the HemoScreen? with the Sysmex XN device. In the study we analyzed 104 samples from the cardiothoracic, neuro and general intensive care units.

The HemoScreen? technique showed good precision, with total coefficient of variation of 1–2% for RBCs and 3–5% for PLTs. Deming correlations between the HemoScreen and the Sysmex XN instrument analyzer: (WBC_HemoScreen? = 1.061* WBC_Sysmex - 0.644; r = 0.995), RBC (RBC_HemoScreen? = 0.998* RBC_Sysmex + 0.049; r = 0.993) for WBC and (Platelets_HemoScreen? = 1.087* Platelets_Sysmex – 14.80; r = 0.994) for PLT. The HemoScreen? device provided rapid and accurate test results to evaluate the need for RBC and PLT transfusion. This new technology is promising given that it allows the analysis of WBCs, RBCs, and PLTs further out in the healthcare organization compared with laboratory infrastructure based on traditional cell counters.     

The effects ex vivo and in vitro of insulin and C-peptide on Na/K adenosine triphosphatase activity in red blood cell membranes of type 1 diabetic patients

The decrease in Na/K adenosine triphosphatase (ATPase) activity observed in several tissues of type 1 diabetic patients is thought to play a role in the development of long-term complications. Infusion of insulin may restore this enzyme activity in red blood cells (RBCs), and recent arguments have been developed for a similar role of C-peptide. The aims of this study were to determine whether insulin acts directly on the RBC enzyme and to evaluate the effect of C-peptide on Na/K ATPase activity. Thirty-nine C-peptide-negative type 1 diabetic patients were studied (blood glucose, 11.2 +/- 1.49 mmol/L; hemoglobin A1c [HbA1c], 8.9% +/- 0.1%, mean +/- SEM). Blood samples were obtained in the morning, before breakfast and insulin injection. Intact and living RBCs were resuspended in their own plasma and incubated with or without insulin (50 microU/mL) or C-peptide (6 nmol/L). Ex vivo by microcalorimetry, the heat produced after 1 hour by the enzyme-induced hydrolysis of adenosine triphosphate (ATP), was measured in a thermostated microcalorimeter at 37 degrees C. The results showed that Na/K ATPase activity was significantly increased by insulin (12.4 +/- 0.5 v 15.4 +/- 0.9 mW/L RBCs, P < .05, n = 23) but not by C-peptide (11.9 +/- 0.7 v 12.9 +/- 0.9 mW/L RBCs, NS, P = .26, n = 12). In another experiment, RBC suspensions were incubated at 37 degrees C in a water bath with or without insulin (50 microU/mL) or C-peptide (6 nmol/L) for 10 minutes. RBC membranes were isolated and Na/K ATPase activity was assessed by measuring inorganic phosphate release at saturating concentrations of all substrates. The results showed that insulin and C-peptide significantly increased RBC Na/K ATPase activity (342 +/- 25, P < .005 and 363 +/- 30, P < .005, respectively v255 +/- 22 nmol Pi x mg protein(-1) x h(-1), n = 14). We conclude that insulin and C-peptide act directly on RBC Na/K ATPase, thus restoring this activity in type 1 diabetic patients. The stimulatory effect of C-peptide observed in vitro on RBC Na/K ATPase activity confirms that C-peptide plays a physiological role.     

MCS+和Trima血细胞分离机采集双份单采血小板的分析

目的:分析2种血细胞分离机MCS+、Trima采集双份单采血小板的情况,以便指导双份血小板的采集。方法:比较150名MCS+血细胞分离机和100名Trima Accel血细胞分离机献血者血液参数以及采集过程参数。结果:统计表明,2组献血者的血液参数无明显差异。采集参数中,MCS+组的处理血量、抗凝剂使用量少于Trima组,但采集时间大于后者,而血小板采集量和采集效率均低于后者。结论:为献血者选择合适的血细胞分离机,更好地完成双份单采血小板的采集。     

Study of hematopoietic progenitor cells, hematological values and lymphocyte subsets in cord blood: application for cord blood transplantation

Hematological values, lymphocyte subsets and hematopoietic progenitor cells from normal term cord blood samples were studied, compared with normal adult blood, and analysed to determine whether a single collection of cord blood is sufficient for transplantation in adults. The parameters were assayed by automatic cells counter, flow cytometry and semisolid cell culture. All of the hematological values except RBC and MCHC were higher than in normal adult blood. Sex had an influence on RBC, Hb, Hct, Plt and reticulocyte counts. For lymphocyte subsets, all of the absolute CD3+, CD4+, CD8+ counts and T helper: suppressor ratio were higher than those of adult blood. All of the hematopoietic progenitor cells in cord blood were also higher than in adult blood. The mean volume of cord blood for each collection was 80.75 +/- 4.81 ml and the mean numbers of nucleated cells, CFU-GM and CD34+ were 13.51 +/- 0.38 x 10(8) cells, 4.33 +/- 0.66 x 10(5) colonies and 42.65 +/- 7.00 x 10(5) cells respectively. This 80 ml of cord blood would contain sufficient marrow repopulating cells for a recipient weighing about 20 kg. Recently developed technology, including ex vivo expansion may even permit transplants in adults.     

Large-scale mobilization and isolation of CD34+ cells from normal donors

We describe collection and purification of peripheral blood CD34+ cells from volunteer, normal donors and allogeneic stem cell donors. A total of 98 aphereses were performed on 68 volunteer donors using peripheral venous access. The mean number of nucleated cells collected was 4.6 x 10(10) which included 1.9 x 10(8) CD34+ cells corresponding to 2.7 x 10(6) CD34+ cells/kg. The number of CD34+ cells collected did not differ between males and females but did correlate with the donor's weight and the total number of nucleated cells collected. The Nexell Isolex 300i cell separator was used to isolate CD34+ cells from 30 of the collections. A mean of 0.36% of the total cells was recovered and included 43 +/- 18% of the CD34+ cells. CD34+ cells represented 85 +/- 11% of the recovered cells. The total number of CD34+ cells recovered was not influenced by the number of nucleated cells placed on the Isolex 300i. The percentage of CD34+ cells recovered was not related to the number of CD34+ cells placed on the Isolex 300i. The purity of the final product was influenced by the number of CD34+ cells but not the total number of nucleated cells. An additional 38 CD34+ cell isolations were performed on normal allogeneic stem cell donors with similar results. These observations further support the safety and feasibility of peripheral blood CD34+ cell collection and purification.     

Rheological properties of fetal red cells with special reference to aggregability and disaggregability analyzed by light transmission and laser backscattering techniques

Blood viscosity factors and fetal erythrocyte aggregability were investigated with light transmission (Myrenne device) during a cross-sectional study of blood drawn in utero by cord venepunctures in 119 normal fetuses between 18 and 39 weeks gestation. There was a progressive increased blood viscosity at native hematocrit (p < 0.01) explained by a gradual increase in both hematocrit (from 33% to 40%, p < 0.05) and Dintenfass' 'Tk' RBC rigidity index (p < 0.05), while plasma viscosity remained constant at 1.18 +/- 0.01 mPa x s as well as the h/eta ratio (188.4 +/- 2.7 mPa(-1) x s(-1)). The RBC aggregation index 'M' remained almost equal to zero (mean value: 0.04 +/- 0.01) before 32 wk gestation and then increased (p < 0.05) until delivery. The upper physiological limit for this parameter before 32 wk (mean +/- 2 SD) is 0.18. The RBC aggregation index 'M1' remained constant during pregnancy at 2.98 +/- 0.26, i.e., the upper physiological limit for this parameter during the intrauterine life (mean +/- 2 SD) is 7.85. Both fibrinogen (r = 0.479, p < 0.05) and albumin (r = 0.494, p < 0.01) correlated with time so that the albumin/fibrinogen ratio remained stable. We then studied with the laser retrodiffusion technique the venous blood of 20 women (18-43 yr, 37-40 wk gestation) and the cord blood of their newborns at birth, comparing RBC aggregation of: mothers (M), maternal RBCs resuspended on newborn plasma (MF), newborn RBCs resuspended on maternal plasma (FM), and newborns (F). Aggregability is higher in M (RBC aggregation time M < MF < FM < F; p < 0.01); RBC aggregation index at 10 s M > MF > FM > F; p < 0.01), with in turn the symmetric inverse picture for the partial disaggregation threshold (M > MF = FM > F). Thus RBC disaggregability is higher in newborns, and suspensions on maternal and newborn plasma suggest that half of this difference in aggregability (and disaggregability) between fetal and adult blood results from plasma factors and another half from erythrocytes.     

Cobe Spectra is superior to Fenwal CS 3000 Plus for collection of hematopoietic stem cells

One hundred and seventy-seven stem cell apheresis procedures performed on 91 patients using the Fenwal CS 3000 Plus cell separator and 61 procedures performed on 37 patients using the Cobe Spectra cell separator were studied to compare the CD34(+) cell collection efficiencies (CE; the proportion of the total CD34(+) cell content in the blood volumes processed that is harvested) of the two machines. The absolute peripheral blood CD34(+) cell count was comparable for the two groups (P = 0.27). A strong correlation was seen between the blood CD34(+) cell count and the total number of CD34(+) cells collected for the Spectra (r(2) = 0.59; P < 10(-6)) and for the CS 3000 Plus (r(2) = 0.60; P < 10(-6)). No significant correlation emerged between the peripheral blood CD34(+) cell count and the CE of either machine. The total number of CD34(+) cells collected per procedure was comparable (P = 0.51): median 113 x 10(6) for CS 3000 Plus and median 218 x 10(6)for Spectra. CE was significantly higher with the Spectra (median 45.7%, range 9.8-98.6%) than the CS 3000 Plus (median 30.3%, range 1.7-89.3%; P < 0.00001). We conclude that the CD34(+) cell CE of the Spectra is superior to that of the CS 3000 Plus. Therefore, under the usual clinical conditions, Cobe Spectra should be used preferentially for peripheral blood progentor cell collection to maximize the number of hematopoietic stem cells collected.     

Peripheral blood stem cell collection in 24 low-weight infants: experience of a single centre

Peripheral blood stem cells (PBSC) harvest may be difficult in young children. Extracorporeal separator line priming by red blood cells is usually required to improve haemodynamic tolerance and efficacy of collection. We present our experience with 24 children weighing less than 15 kg treated between January 1997 and September 1999, in whom we tried to avoid systematic blood priming. The median age and weight at the time of apheresis were 2.4 years and 12 kg, respectively. A total of 48 PBSC were performed. When haemoglobin was less than 12 g/dl, packed red cells were transfused before collection (40% of aphereses). The median cell yield per apheresis was 7.1 (2.2-30.6)x10(6)/kg CD34(+) cells and 16.0 (3.3-44.3)x10(5) CFU-GM/kg. Initial collection failed in three cases. Four children required an additional haematopoietic progenitor mobilization. This procedure allowed PBSC collection without transfusion in 37.5% of children, and was safe (two serious and five mild transient side effects) and effective (median CD34(+) cells collected per child: 7.1 x 10(6)/kg (4.6-30.6) and CFU-GM: 15.1 x 10(5)/kg (4.7-44.3)). Despite their low weight, insertion of a femoral catheter was avoided in 43% of children.     

Fresh-frozen plasma and platelet transfusions are associated with development of acute lung injury in critically ill medical patients

BACKGROUND: Transfusion has long been identified as a risk factor for acute lung injury (ALI)/ARDS. No study has formally evaluated the transfusion of specific blood products as a risk factor for ALI/ARDS in critically ill medical patients. METHOD: In this single-center retrospective cohort study, 841 consecutive critically ill patients were studied for the development of ALI/ARDS. Patients who received blood product transfusions were compared with those who did not, in univariate and multivariate propensity analyses. RESULTS: Two hundred ninety-eight patients (35%) received blood transfusions. Transfused patients were older (mean [+/- SD] age, 67 +/- 17 years vs 62 +/- 19 years; p < 0.001) and had higher acute physiologic and chronic health evaluation (APACHE) III scores (74 +/- 32 vs 58 +/- 23; p < 0.001) than those who had not received transfusions. ALI/ARDS developed more commonly (25% vs 18%; p = 0.025) in patients exposed to transfusion. Seventeen patients received massive RBC transfusions (ie, > 10 U of blood transfused within 24 h), of whom 13 also received fresh-frozen plasma (FFP) and 11 received platelet transfusions. When adjusted for the probability of transfusion and other ALI/ARDS risk factors, any transfusion was associated with the development of ALI/ARDS (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.24 to 3.75). Among those patients receiving individual blood products, ALI/ARDS was more likely to develop in patients who received FFP transfusions (OR, 2.48; 95% CI, 1.29 to 4.74) and platelet transfusions (OR, 3.89; 95% CI, 1.36 to 11.52) than in those who received only RBC transfusions (OR, 1.39; 95% CI, 0.79 to 2.43). CONCLUSION: Transfusion is associated with an increased risk of the development of ALI/ARDS in critically ill medical patients. The risk is higher with transfusions of plasma-rich blood products, FFP, and platelets, than with RBCs.     

Prolonged storage of red blood cells affects aminophospholipid translocase activity

BACKGROUND AND OBJECTIVES: Loss of phospholipid asymmetry in the membrane of red blood cells (RBC) results in exposure of phosphatidylserine (PS) and to subsequent removal from the circulation. In this study, we investigated the effect of long-term storage of RBCs on two activities affecting phospholipid asymmetry: the ATP-dependent aminophospholipid translocase (or flippase, transporting PS from the outer to the inner leaflet) and phospholipid scrambling (which will move PS from the inner to the outer leaflet). MATERIALS AND METHODS: Standard leukodepleted RBC concentrates were stored in saline-adenine-glucose-mannitol (SAGM) at 4 degrees C for up to 7 weeks. PS exposure was determined by measurement of AnnexinV-FITC binding to the cells, flippase activity by measurement of the inward translocation of NBD-labelled PS. Scrambling activity was determined by following the inward translocation of fluorescent NBD-phosphatidylcholine. In parallel, intracellular ATP levels were determined. RESULTS: PS exposure amounted to only 1.5 +/- 0.3% positive cells (n = 8) after 5 weeks of storage, which slightly increased to 3.5 +/- 0.7% (n = 8) after 7 weeks of storage. Flippase activity started to decrease after 21 days of storage and reached 81 +/- 5% of the control value after 5 weeks of storage (n = 6) and 59 +/- 6% (n = 6) after 7 weeks. Also in RBC obtained by apheresis, flippase activity decreased upon storage. Scrambling activity remained virtually absent during storage, explaining the low PS exposure despite the decrease in flippase activity. Rejuvenation of RBC after 7 weeks to increase ATP levels only partially restored flippase activity, but in combination with a correction of the intracellular pH to that of fresh cells, almost complete restoration was achieved. The decrease in flippase activity after prolonged storage did make the RBCs more prone to PS exposure after activation of phospholipid scrambling. CONCLUSION: This study shows that, although PS exposure remains low, prolonged storage does compromise the RBC membrane by affecting flippase activity. When the metabolic changes induced by storage are corrected, flippase activity can be restored.