Reduced deformability of stored red blood cells is associated with generation of extracellular vesicles

Throughout storage, red blood cells (RBCs) undergo detrimental changes in viability and their ability to effectively transport oxygen. RBC storage lesions are mediated, in part, by a progressive loss of cell deformability, and associated with the release of extracellular vesicles (EVs). Accumulation of EVs during the storage of RBCs correlates with a decrease in RBC surface area to volume ratio. Similarly, the loss of RBC-deformability is associated with loss of RBC surface area to volume ratio. In this study we thus tested whether loss of RBC-deformability is associated with increased RBC-EV production during blood storage.EVs obtained by differential centrifugation of stored RBCs (non-leukoreduced non-irradiated or leukoreduced γ-irradiated RBCs stored 35 or 28 days respectively) were enumerated by high-sensitivity flow cytometry. RBC deformability was quantified, using a cell-flow-properties-analyzer, by measuring the median cell elongation ratio (MER) and percentage of low and high deformable cells in the population (%, LDFC, and HDFC, respectively).The number of EVs was inversely correlated with the MER and positively correlated with the %LDFC with both measures showing highly significant logarithmic dependence with EV levels in stored RBCs. Considering how highly deformable cells did not correlate with EV formation as compared with low deformable RBCs we propose that the formation of EVs is a key factor leading to increased RBC-rigidity.     

献血人群红细胞血型意外抗体的检出率及分布情况

目的了解该地区献血人群红细胞血型意外抗体的发生频率和分布特点,为提高用血安全提供理论依据。方法对2012年1～12月健康献血者进行意外抗体筛查,抗体筛查阳性者做进一步特异性鉴定,并分析其发生频率和分布特点。结果在195404例血液标本中,共检出意外抗体59例,阳性率为0．030％。其中lgM抗体52例,阳性率为0．027％;IgG抗体7例,阳性率为0．004％,男女性别间阳性率比较,女性高于男性,差异均有统计学意义（P〈0．05）。共检出特异性抗体36例,占61．02％,非特异性抗体23例,占38．98％。结论献血人群有一定意外抗体检出率,意外抗体筛查应列入献血者常规检测项目,以保证用血安全。     

Unit-to-unit variability in the deformability of red blood cells

BackgroundIn blood banking practice, the storage duration is used as the primary criterion for inventory management, and usually, the packed red blood cells (PRBC) units are supplied primarily according to first-in-first-out (FIFO) principle. However, the actual functionality of individual PRBC units is mostly ignored. One of the main features of the RBCs not accounted for under this approach is the deformability of the red cells, i.e., their ability to affect the recipients' blood flow. The objective of the study was to analyze unit-to-unit variability in the deformability of PRBCs during their cold storage.MethodsRBC samples were obtained from twenty leukoreduced PRBC units, stored in SAGM. The deformability of cells was monitored from the day of donation throughout 42 days. RBC deformability was determined using the computerized cell flow-properties analyzer (CFA) based on cell elongation under a shear stress of 3.0 Pa, expressed by the elongation-ratio (ER). The image analysis determines the ER for each cell and provides the ER distribution in the population of 3000–6000 cells.ResultsThe deformability of freshly-collected RBCs exhibited marked variability already on the day of donation. We also found that the aging curve of PRBC deformability varies significantly among donors.SignificanceThe present study has demonstrated that storage duration is only one of the factors, and seemingly not even the major one, affecting the PRBCs functionality. Therefore, the FIFO approach is not sufficient for assessing the potential transfusion outcome, and the PRBC functionality should be determined explicitly for each unit.     

Duration of red blood cells storage and outcome in critically ill patients

Purpose

There is conflicting evidence on the effect of red blood cells (RBC) storage duration and clinical outcomes. We aimed to investigate the association between RBC storage duration and clinical outcomes in patients admitted to the intensive care unit (ICU).

Materials and Methods

We retrospectively (2001-2011) studied adults admitted to the ICUs of 2 hospitals who received RBC. Using the mean, maximum and minimum age of RBC units transfused, we evaluated the association between RBC storage duration and mortality. We also analyzed the association between mean age of RBC units and length of stay (LOS) in survivors. We performed sensitivity analyses in patients who only received RBC in ICU and who only received leukodepleted RBC.

Results

We studied 8416 patients who received a median of 4 (interquartile range, 2-7) RBC units. After multivariate analysis, age of RBC was not independently associated with mortality, including in the subgroup analyses. Furthermore, there was no clinically relevant relationship between mean RBC age and LOS.

Conclusions

RBC storage duration was not associated with increased mortality nor ICU and hospital LOS. These results support the view that the effect of RBC storage duration on outcomes in critically ill patients is uncertain.     

Automated collection of blood components: their storage and transfusion

The performance of an automated device, the Gambro TRIMA, was evaluated for component production, and an in vivo assessment of the platelets was carried out. Red cell concentrates (RCCs), platelets and plasma were collected and stored according to standard blood bank procedures and evaluated for quality by in vitro measurements. Additionally, single-donor platelets (n=10) were transfused to thrombocytopenic patients after 5 days of storage. Platelet counts were measured after 1 h and the corrected count increment (CCI) was calculated. No significant changes were seen before or after procedure in donor haemoglobin, haematocrit, coagulation factors or platelet count. Return-line samples showed no increase in the level of plasma haemoglobin. Plasma haemoglobin and potassium increased following RBC storage, but there was no change in the red cell number. Platelet aggregation decreased from 52 to 11% (adenosine diphosphate) and the Kunicki morphology score dropped from 379 to 174. Little change was seen in the hypotonic shock response (69-63%) or in the percentage of CD62 expression (4.8-19.8) over time. The CCI averaged 28+/-26 x 10(3) microL(-1) in 10 patients 1 h after transfusion. The TRIMA machine collects RCCs, platelets and plasma in a variety of combinations in one session. For autologous collection, two units of RCC plus platelets can be collected at one time, reducing administrative and testing costs. The platelets have good in vivo recovery, as shown by the CCI values. An added advantage is that the TRIMA machine can be used in hospitals to generate components in times of shortage without the need for a component's laboratory.     

Impact of red blood cells transfusion on ICU-acquired bloodstream infections: A case-control study

Our study investigated the impact of packed red blood cell (pRBC) transfusion on the occurrence of bloodstream infections (BSIs) in patients admitted in a multidisciplinary intensive care unit (ICU), further assessing potential associations with particular BSI types. A nested matched (1:1) case-control design was implemented. Sex, age, admission category, Acute Physiology and Chronic Health Evaluation score II (plus Injury Severity Score in trauma patients) were used for matching. Controls were selected to have an ICU length of stay at least equal to the time to first BSI episode of the corresponding cases. Propensity scores for receiving pRBC transfusion were calculated in the entire prospective cohort. Of 582consecutive ICU patients, 165 matched case-control pairs were formed. In multivariable analysis, pRBC transfusion was independently associated with 2-fold probability for BSI (adjusting for matching variables and propensity score). There was a significant dose-dependent association of BSI risk with regard to the number of pRBC units transfused (odds ratios [OR], 1.73, 2.09, 2.34 for 1-3, 4-6, and more than 6 pRBC units transfused, respectively, compared with nontransfused patients, P values .116, .018, and .015, respectively). In subgroup analysis, catheter-related BSIs displayed the strongest association with pRBC transfusion (OR = 5.01, P = .014).     

Apheresis red blood cells associated with repeated hemolysis during blood priming of the Cellex Photopheresis System

Extracorporeal photopheresis (ECP) in young pediatric patients has a risk for procedural hypotension and anemia due to extracorporeal fluid shifts. A standard mitigation policy in these patients is to prime the device with packed red blood cells (RBC) or whole blood. We now report multiple episodes of hemolysis while attempting to prime the Therakos Cellex in a pediatric transplant patient undergoing a course of ECP for severe graft-vs-host-disease. Over the course of 40 ECP treatments, hemolysis was observed on five occasions. An extensive investigation found an association between hemolysis and apheresis RBC (A-RBC). Of 46 RBC units dispensed for blood priming, hemolysis occurred with 22% (4 of 18) of A-RBC and accounted for 80% (4 of 5) of all hemolysis episodes. Hemolysis was significantly higher with A-RBC when compared with RBC collected by whole blood donations (WB-RBC: 3.5% [1 of 28]; P = .049). A comparison of RBC attributes, including unit age, showed that hemolyzed A-RBC units tended to be younger than both nonhemolyzed RBC (6.5 vs 10.3 days, P = .018) and WB-RBC (8.5 days, P = .10). We hypothesize that A-RBC may exhibit “sublethal” RBC damage following prior exposure to centrifugal shear and negative forces at the time of collection, leading to a decrease in RBC deformability and increased susceptibility to hemolysis. This is the first report showing an increased susceptibility to hemolysis with A-RBC during priming of the Cellex.     

血常规标本存放条件对血细胞计数的影响

目的 探讨血常规标本存放条件对检测结果的影响.方法 所有全血标本室温或4 ℃条件下存放,连续5 d应用Sysmex KX-21全自动血细胞分析仪进行检测,并进行统计学分析.结果 室温下存放标本,白细胞(WBC)于48 h、红细胞(RBC)于96 h、血小板(PLT)于24 h、血红蛋白(Hb)于120 h、血细胞比容(...     

Duffy、Diego等4种血型系统基因频率及多态性研究

目的了解岳阳汉族人群Kidd(Jk^a/Jk^b)、Duffy(Fy^a/Fy^b)、Diego(Di^a/Di^b)、Dombrock(Do^a/Do^b)4种红细胞血型系统的基因频率和多态性特点,为建立该地区稀有血型库提供数据支持。方法采用聚合酶链式反应-序列特异性引物法(PCR-SSP法)对303名岳阳汉族RhD(+)固定献血者进行4种血型系统基因分型。结果岳阳汉族人群Duffy血型的基因频率为Fy^a=0.9472,Fy^b=0.0528;Dombrock血型基因频率为Do^a=0.0842,Do^b=0.9158;Diego血型基因频率为Di^a=0.0247,Di^b=0.9752;Kidd血型基因频率为Jk^a=0.4802,Jk^b=0.5198。结论岳阳汉族人群Duffy、Diego、Kidd和Dombrock血型系统基因呈多态性分布。     

冻存前滤除白细胞对解冻红细胞质量影响的研究分析

目的探讨冻存前滤除白细胞对冰冻解冻去甘油红细胞的血液质量和生化指标的影响。方法随机采集20名无偿健康献血者全血400mL×20袋,常规分离血浆制备成悬浮红细胞2μ×20袋。根据配对设计方法,将血液等量分成两份1μ×20袋,其中20袋在2~4℃静置2~4h后用一次性白细胞滤器滤除白细胞为滤白组,另20袋不做其他处理为非滤白组。两组红细胞经40%甘油化后冻结,保存在低于-65℃的超低温冰箱至少30d,解冻后红细胞复悬于MAP红细胞保存液中,4℃保存。分别在0、7、14、21d检测解冻红细胞的血液学和生化学指标。结果滤白组冰冻解冻去甘油红细胞较非滤白组冰冻解冻去甘油红细胞的溶血率低、氨浓度低及ATP浓度高,两组比较差异有统计学意义(P0.05)。滤白组可见LDH水平明显抑制,钾浓度增加速度相对较缓。结论滤白组解冻红细胞长期生存能力较非滤白组解冻红细胞强。     

红细胞密度与天龄相关性研究

目的研究红细胞密度与天龄的相关性,不同密度红细胞所对应的平均天龄。方法采用非连续密度梯度分离方法,将全血红细胞分为6个不同密度的红细胞部分。测定不同部分红细胞丙酮酸激酶活性,通过各部分丙酮酸激酶活性与全血红细胞丙酮酸激酶活性的比值(Ratio)推测各部分红细胞平均天龄;测定各部分红细胞膜表面磷脂酰丝氨酸(PS)表达阳性率,来反映红细胞密度与衰老(天龄)的相关性。结果根据红细胞比值,各部分红细胞平均天龄由低密度至高密度依次为11.5、466、3.87、4.6、80.5、102.2 d。随着红细胞密度的增加,PS表达阳性率也逐渐增高。结论不同密度的红细胞代表不同的细胞天龄,采用密度梯度分离方法可以分离出不同天龄段的红细胞,为进一步研究红细胞天龄与功能的相关性提供了方法学基础。