Blood bank issues associated with red cell exchanges in sickle cell disease

Sickle cell disease (SCD) patients are prone to develop complications that include stroke, acute chest syndrome, and other crises. Some of these complications require chronic transfusion therapy or red cell exchange (RCE), either for therapeutic or prophylactic reasons. Due to a discrepancy of red cell antigens between African Americans and Caucasians (majority blood donors), the incidence of alloantibody formation is very high, which makes it difficult to find compatible red cell units, especially for urgent RCE. Some of the above conditions require immediate oxygen delivery to the tissues. Thus, SCD patients undergoing RCE should receive red blood cells with special attributes that include matching for Rh and Kell blood group antigens; RBCs should be fresh in order to provide (1) immediate oxygen delivery and (2) longer surviving cells to reduce the interval between RCE. Also, these units should be pre-storage leukoreduced to prevent febrile non-hemolytic reactions and screened for sickle cell traits to avoid transfusing red cells containing HbS. This requires a concerted effort between the apheresis unit, the local blood bank, and the central blood supplier.     

Improved red cell quality after erythroplasmapheresis with MCS-3P

The cell separator MCS-3P is an apheresis system offering the flexibility to collect standardized red blood cells, plasma, and/or platelets from one donor. Two different programs were used for the red cell apheresis'RBCP (collection of one unit of red cells and two units of plasma) and RBCPS (one unit of red cells and one unit of plasma). The quality of the red cell concentrates (RCC resuspended in SAG-Mannitol) during the storage time of 42 days was measured by biochemical (ATP, 2,3-DPG, pH, free Hb, free potassium, glucose, lactose, p⁵⁰, hemoglobin derivatives) and Theological (morphological index, filtration/rigidity index) parameters. The donation time with 53 donors was 20 min for 355 ml RCC-SAGM and 440 ml plasma and 7 min for 335 ml RCC-SAGM and 239 ml plasma. The donor tolerance was analogous to plateletpheresis or plasmapheresis. Twenty units of the RCC-SAGM were in-line filtered within 6 or 24 hours after donation. The results obtained for red blood cell storage are at least as good as with standard collection (free hemoglobin, free potassium, glucose, lactose, hemolysis) or better (ATP, 2,3-DPG, p⁵⁰, hemoglobin derivatives, filtration/rigidity index) owing to prevention of collection lesion. All blood preparations were sterile after storage (red cells 42 days, plasma after freezing). The erythroplasmapheresis with MCS-3P can be especially recommended for application in an autologous blood program because the application of autologous blood donation in hospitals is often limited by the preconditions of component separation. The erythroplasmapheresis data with MCS-3P are encouraging for the development of a new blood collection methodology.     

Improved method for automated red cell exchange in sickle cell disease

An improved method for intermittent-flow erythrocytapheresis in patients with sickle cell disease is reported. The method, a modification of the standard red cell exchange procedure for the Haemonetics 30S unit, dilutes with physiologic saline the patient's blood as it flows from the draw line and before it reaches the centrifugation bowl. The blood dilution (approximately 1.6 parts saline to 1 part blood) is used only during the first two passes, when the proportion of sickle erythrocytes in the patient's blood is still high. Only that amount of bowl supernatant (saline-diluted plasma) necessary to maintain extracorporeal volume below 500 ml is returned to the patient. The method described largely prevents the clumping of sickle erythrocytes in the centrifugation bowl, a complication frequently encountered with the Haemonetics 30S unit. Thus, changing the bowl between passes is avoided. Furthermore, the sickle red cells can be collected with the first pass and cryopreserved for possible future uses including the option of autotransfusion.     

Evaluation of noninvasive methods for the estimation of haemoglobin content in red blood cell concentrates

Objectives: Red blood cell concentrates (RCCs) are the major blood component transfused to patients. There is a great variability in patient response, depending on both the patient's blood volume and haemoglobin content in the RCC. Standardisation of transfusion practice is needed to improve the prediction of patient outcome. Aim: We hypothesise that labelling of RCCs with haemoglobin content will add possibilities for the standardisation of transfusion practice. Methods: Data from multiple international transfusion services regarding haemoglobin content and weight or volume of RCC were collected and analysed. Results: We demonstrate a strong and highly significant correlation between haemoglobin content with both weight and volume of the RCCs. A linear regression model was used to assess these relationships, and it demonstrates how haemoglobin content can be estimated for different cell production processes. Conclusions: We recommend the use of weight or volume of the RCCs as the basis of estimating haemoglobin in the RCC and postulate that this can be used in future studies to explore the effects of a haemoglobin dose‐based transfusion system. As the weight – and sometimes the volume – of the blood bag is easily accessible, in contrast to direct haemoglobin measurements from each individual unit, this method is feasible and simple.     

113名地中海贫血患者输注2629袋红细胞情况分析

目的掌握"地贫之家"患者的用血规律,为开展"地贫之家"的医院提供参考。方法对本院2016年6月开设"地贫之家"起至2019年5月的113名地中海贫血患者的2 629袋红细胞输注情况进行回顾性分析。结果 "地贫之家"患者ABO血型分布与所在的华南地区ABO血型分布大致相当。患者中位数年龄为9岁(6,15),93.8%(106/113)为30周岁以下,尤其以儿童及青少年为主。总体用血量逐渐增加,每年1月至2月和7月至8月的寒暑假回落,主要集中在非工作日输注。结论新建"地贫之家"用血有一定规律,输血科可参考患者的血型分布、用血周期变化制定储血计划,安排人力资源,合理安全使用血液资源。     

ACP-215全自动红细胞处理仪制备红细胞制品的可靠性研究

目的：研究ACP-215全自动红细胞处理仪制备红细胞制品的可靠性。方法：将研究对象分成两组,对照组采用手工开放式洗涤法制备,试验组采用ACP-215全自动红细胞处理仪制备。解冻去甘油红细胞和洗涤红细胞按照相关标准,分别对实验组和对照组红细胞回收率、游离血红蛋白、甘油含量、残留白细胞、体外溶血试验和细菌培养进行检测分析。结果：对于解冻去甘油红细胞,实验组在红细胞回收率、残留白细胞、甘油含量、体外溶血和细菌培养均好于对照组;对于洗涤红细胞,实验组在红细胞回收率、残留白细胞量和上清液蛋白含量方面优于对照组结论：用ACP-215全自动红细胞处理仪制备红细胞制品,比手工洗涤法更安全可靠,尤其在解冻去甘油红细胞方面,体现的更明显。该仪器有实际应用价值,值得推广。     

不同保存期全血制备洗涤红细胞的超微结构变化

目的 探讨不同保存期的全血制备洗涤红细胞前后电镜下红细胞形态的变化。方法 采集CPD—A抗凝全血。实验分Ⅰ～Ⅵ组，分别于4℃保存7、10、15、20、25、30d。于制备前取全血1滴，5％戊二醛固定，经2000r／min离心10min后，分出血浆，取样检测血红蛋白。余下的红细胞再加等量生理盐水，1500r／min离心5min，连续2次，取样为制备后测定组。结果 组Ⅰ和组Ⅱ制备前后红细胞成双面凹的圆盘结构，细胞均匀混悬。组Ⅲ制备前红细胞形态正常，制备后少数红细胞出现聚集状、球形或边缘不整齐，并有棘形红细胞出现。组Ⅳ、组Ⅴ、组Ⅵ于制备前血浆微红；制备后，球形红细胞、棘形红细胞、中问漏孔的红细胞增加。结论 制备洗涤红细胞的最佳时间应在4℃保存10d内的全血，保存15d以后的全血制备洗涤红细胞形态发生异常变化，出现棘形红细胞，囊泡化后的红细胞易溶血，红细胞寿命缩短，影响洗涤红细胞的质量。     

Comparison of two double red cell collection settings on Fenwal Alyx apheresis instrument

The Fenwal Alyx for collecting double red cell products has two red cell volume collection settings: fixed collection target of 360 ml (180 ml/unit) and a variable target of collecting either 400 or 360 ml (200 or 180 ml/unit), where the machine aims for the higher possible collection target. We retrospectively compared the two collection targets for the RBC content, donor time, technician time, and collection efficiency. We compared 18 fixed (F) target collections to 40 variable (V) target collections. All collections were performed as per the manufacturer's recommendations on Alyx and donors met the manufacturer's eligibility criteria. There was no significant difference in average whole blood processed (F: 963 ml, V: 1,000 ml); donor time (F: 43 min, V: 45 min) or technician time (F: 64 min, V: 64 min). There was a significant difference in unit volume (F: 283 ml, V: 300 ml); grams Hb/unit (F: 53 g, V: 57 g); ml RBC/unit (F: 157 ml, V: 167 ml); and RBC recovery (F: 87.8%, V: 88.9%). The fixed target had a significantly lower frequency of products with ≥51 g Hb (80.6%) than variable target (96.3%) and ≥153 ml RBC/unit (F: 55.6%, V: 96.3%). In conclusion, the variable target efficiently allows collections of products with higher red cell volume and hemoglobin without a significant increase in collection and processing time.     

保存人红细胞的新策略一抗氧化剂保养液保存效果的研究

塑料血袋盛义务献血员的静脉血（含适量保养液）并置4℃冰箱保存。在保存前、后不同时间检查各项指标,旨在研究抗氧化剂保养液延长人血红细胞在4℃条件下的保存时间,以缓解血液保存供应的压力,为输血抢救创造有利条件。实验分3组：ACD组,GMA组和抗氧化剂（SOD）组）。研究结果表明,在4℃条件下保存75天后SOD组红细胞血红蛋白回收率为87．2％,血浆血红蛋白（mg/L)为193．2,P50（mmHg)为34．0（正常值为33．1）,最大变形指数（DImax）为0．2413,即为正常值的74．3％,外观检查无明显溶血、变色、气泡和凝块。结论提示,用抗氧化剂保养液保存红细胞在4℃条件下可延长75天,其红细胞血红蛋白和血浆血红蛋白回收率附合国家《血站基本标准》规定要求。     

Chemokine receptors expressed on T cells in packed red blood cell units change over storage time

The transfusion of blood products is associated with adverse events that are related to the leukocytes in stored units of blood. These leukocytes have been shown to promote the elaboration of inflammatory cytokines. However, the status of a set of key inflammatory mediators, chemokine receptors, expressed on T lymphocytes in stored red blood cell (RBC) units is largely unknown. We investigated the expression pattern of selected chemokine receptors on T cells from non-leukocyte-reduced RBC units over storage time. Selecting segments from stored RBC units, we evaluated the T-cell subsets for the chemokine receptors CXCR3 and CCR4 by flow cytometry. Statistical analysis was performed by regression analysis. We analysed 30 samples stored between 5 and 38 days. The CD4+ T cells expressing CXCR3 increased by 0.27% daily (P= 0.02), whereas the expression of CCR4 declined by 0.40% daily (P < 0.001). Though the expression of the chemokine receptors on CD8+ cells followed the same trend, the changes were statistically nonsignificant. This study suggests that a longer duration of storage is associated with a higher expression of chemokine receptor CXCR3 and a lower expression of CCR4 on T cells in RBC units, suggesting a pro-inflammatory Th1 bias. The clinical significance of these changes in the setting of adverse transfusion events needs further evaluation.