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1.

Background

The development of alloantibodies may complicate the management of patients with β-thalassemia. An extended antigenic matching may reduce the risk of alloimmunization. Our previous study showed that the introduction of molecular red blood cell (RBC) typing allows finding suitable blood units for multi-transfused patients. The aim of this study was to evaluate the benefit of RBC transfusion with extended antigenic match.

Materials and methods

At the University of Campania “L. Vanvitelli”, we selected β-thalassemia major patients (age ≤23 years), without preformed alloantibodies. Data of patients receiving transfusion of leukoreduced RBC units for a period of one year with partial better match (PBM) including ABO, RhD, C/c, E/e, K/k antigens and consecutive one year with extended match (EM) including ABO, RhD, C/c, E/e, K/k, Fya/Fyb, Jka/Jkb, M/N, S/s antigens, were compared.

Results

Eighteen patients, 8 males and 10 females with a mean age of 15.4 years (6.4 SD) received a mean number of 41.2 (6.0 SD) RBC units transfused with PBM and 41.8 (6.2 SD) with EM protocols. After two years of RBC transfusions with both antigen matching protocols, no new alloantibodies were developed in patients. No significant differences in Hb concentration and volume of RBC transfused were found between PBM and EM protocols.

Conclusions

Thalassemia patients may benefit from receiving RBC transfusions based on extended antigen matching as demonstrated by the lack of new alloantibodies. However, our data show a high concordance between PBM and EM protocols considering pre-transfusion Hb, increment of Hb and volume of RBC transfused.  相似文献   
2.
BackgroundAlthough preoperative anemia has been suggested to predict postsurgical morbidity and mortality among infants < 1 year of age, the data were drawn from heterogeneous patient cohorts including severely ill infants undergoing complex, high-risk procedures. We aimed to determine whether untreated preoperative anemia was associated with increased risk of postoperative complications in infants < 1 year of age who underwent pyloromyotomy, a common and relatively simple surgery.MethodsInfants < 1 year of age undergoing pyloromyotomy were identified from the American College of Surgeons (ACS) National Surgical Quality Improvement Program-Pediatric database. Preoperative anemia was defined as a hematocrit ≤ 40% for infants 0–30 days of age and ≤ 30% for infants more than 30 days of age. Patients who received pre- or postoperative blood transfusions were excluded.ResultsWe identified 2948 patients who met our inclusion criteria, of whom 843 were anemic (29%). The overall rate of complications in this cohort was 6%. The most common postoperative complications were readmission (97 cases), surgical site infection (43), reoperation (39), prolonged hospital stay (24), urinary tract infection (3), 30-day mortality (3) and cardiac arrest (2). We found no differences in the incidence of complications in anemic versus nonanemic patients on bivariate analysis or multivariable logistic regression (adjusted odds ratio = 1.2; 95% confidence interval: 0.8–1.7; P = 0.319).ConclusionsIn relatively healthy infants undergoing pyloromyotomy, untreated preoperative anemia was not associated with postoperative compilations and should not be considered a significant risk factor.Level of evidence III.  相似文献   
3.
Lifetime red cell concentrate (RCC) transfusions still account for significant iron overload‐related morbidity and mortality despite chelation therapy in thalassaemia. The cumulative risk of transfusion‐transmitted infections is substantial for thalassaemia patients. Pathogen reduction technologies for RCC may imply a proactive approach against new/re‐emerging pathogens and may be an ultimate safeguard for transfusion safety in the developing countries. Red cell alloimmunization may become a significant clinical challenge in thalassaemia. The availability of high‐throughput molecular blood group antigen typing in the donors may allow perfect match transfusion, beyond ABO‐D and CEK antigen‐matched transfusions. Allogeneic stem cell transplantation (A‐SCT) is the only available curative therapy in thalassaemia, but carries a substantial risk of serious adverse events and mortality. Gene addition therapy for correction of the α‐globin chain imbalance overcomes the problems of donor availability and immunological complications of A‐SCT. Gene editing by either gene disruption or correction emerged as a potential alternative to gene addition therapy in beta‐thalassaemia. A new era of novel therapeutics targeting α/β imbalance, ineffective erythropoiesis or iron dysregulation is unfolding in thalassaemia management, and a number of those now have agents in preclinical and clinical development. Hydroxyurea (HU) may improve globin chain imbalance and be beneficial for reducing or omitting transfusion requirement. Ruxolitinib has allowed steady decrease in spleen volume that may serve for avoiding splenectomy in beta‐thalassaemia. Luspatercept may restore normal erythroid differentiation and improve anaemia. Hepcidin mimetics or TMPRSS6 inhibitors may modulate ineffective erythropoiesis by iron restriction and improve anaemia and organ iron loading.  相似文献   
4.
We retrospectively assessed the characteristics of 165 MDS patients from our institution having received at least 20 RBC units. In the vast majority of them various comorbidities (range: 1–6 per patient) were registered including mainly cardiovascular disorders. Serum ferritin was over 1000 μg/L in about half of tested individuals. A chelator agent was initiated in 43.6% of patients (mainly low-risk MDS). Transformation in AML occurred in 46 cases (27.8%). Overall, 112 patients died during follow up. The cause of death was documented in 65 cases and included mainly MDS or AML resistance to therapy. There was a context of bacterial or fungal-related sepsis in 35.3% of cases. We noticed a correlation between survival and number of RBC transfusions. Median OS from the 20th RBC unit was significantly prolonged among the chelated subgroup. Consequences of transfusional iron overload and chelation need to be clarified in MDS patients.  相似文献   
5.
Blood transfusion, using the safest conventional blood bioproducts, is an irreplaceable part of substitution therapy. It is considered the most essential supportive clinical intervention aimed to restore the health of patients in need. Nevertheless, numerous unresolved problems are still associated with current blood substitution therapy. To alleviate our dependency on blood donors, many investigators have been focusing on the quest for stem cell-derived blood cells in line with major developments in the field of regenerative medicine. The main objective is to provide a safe and highly standardized universal cultured red cell concentrate [CRBC] for all clinical applications, regardless of blood groups. Currently, we are close to overcoming some of the main obstacles in culturing cells. This concise report is a prelude to the immortalized cell lines that are ready for in vivo clinical trials. It is only through the sharing of experimental ideas and knowledge-based strategies that we will be able to achieve such an enormous task and better understand ‘’the one for all concept’’ of CRBCs and their universal usage in all clinical settings.  相似文献   
6.
7.
Several Plasmodium species exhibit a strong age-based preference for the red blood cells (RBC) they infect, which in turn is a major determinant of disease severity and pathogenesis. The molecular basis underlying this age constraint on the use of RBC and its influence on parasite burden is poorly understood. CD47 is a marker of self on most cells, including RBC, which, in conjunction with signal regulatory protein alpha (expressed on macrophages), prevents the clearance of cells by the immune system. In this report, we have investigated the role of CD47 on the growth and survival of nonlethal Plasmodium yoelii 17XNL (PyNL) malaria in C57BL/6 mice. By using a quantitative biotin-labeling procedure and a GFP-expressing parasite, we demonstrate that PyNL parasites preferentially infect high levels of CD47 (CD47hi)-expressing young RBC. Importantly, C57BL/6 CD47−/− mice were highly resistant to PyNL infection and developed a 9.3-fold lower peak parasitemia than their wild-type (WT) counterparts. The enhanced resistance to malaria observed in CD47−/− mice was associated with a higher percentage of splenic F4/80+ cells, and these cells had a higher percentage of phagocytized parasitized RBC than infected WT mice during the acute phase of infection, when parasitemia was rapidly rising. Furthermore, injection of CD47-neutralizing antibody caused a significant reduction in parasite burden in WT C57BL/6 mice. Together, these results strongly suggest that CD47hi young RBC may provide a shield to the malaria parasite from clearance by the phagocytic cells, which may be an immune escape mechanism used by Plasmodium parasites that preferentially infect young RBC.Malaria, caused by Plasmodium parasites, remains a major cause of mortality and morbidity in the developing world. Among the four principal human Plasmodium species, Plasmodium falciparum is the most virulent, being responsible for more than 90% of malaria-associated deaths. Likewise, Plasmodium species that infect rodents and nonhuman primates also differ widely in their fulminant nature and in the mortality they cause (13). How different Plasmodium species have evolved to exhibit this wide array of virulence and disease severity remains one of the major unsolved questions in malaria biology and pathogenesis.One important factor that is associated with Plasmodium parasite burden and disease severity is the age constraint of the host red blood cells (RBC) they infect. The age-based preference for restricted invasion of RBC by the Plasmodium parasite is characterized as young RBC (reticulocyte), aged RBC (mature), or both young and aged RBC. Plasmodium species that preferentially infect and grow inside young RBC generally cause a low-grade, self-resolving infection that is rarely fatal (e.g., Plasmodium vivax and Plasmodium ovale), whereas those that infect both young and aged RBC cause more fulminant infection that can be fatal in the absence of immunity (e.g., P. falciparum) (1, 46). Thus, along with host genetic background and immune response, restriction for age-specific RBC invasion is a major determinant of the severity and outcome of malaria infection.Malaria parasites have evolved to use redundant receptors and pathways to invade the RBC. For example, sialic acid (7) and Duffy antigen (8) are the major RBC receptors for invasion of P. falciparum and P. vivax, respectively, although other receptors and invasion pathways are known to exist (9, 10). Although a redundancy in RBC receptor use would ensure successful invasion by mitigating the effects of polymorphism and immune targeting, the reasons behind the RBC age-based preference for invasion are not fully clear and remain a subject of debate.Survival of normal cells through the course of their life cycle is essential to maintain homeostasis, and aberrant cells (e.g., senescent or foreign antigen-expressing cells) are eliminated through a sophisticated programmed cell removal system that relies on the recognition of self and nonself determinants (11). CD47, a cell surface molecule in the Ig superfamily, is ubiquitously expressed on many cell types, including RBC, and is a marker of self to avoid early clearance by phagocytic cells through ligation of signal regulatory protein alpha (12). In contrast, altered expression or conformational changes in CD47 may lead to a molecular switch that triggers a phagocytic signal to remove aged or damaged cells (11). Recent studies have shown that the level of CD47 expression is higher in progenitor cells and declines as they undergo maturation and are subsequently aged (13). This age-dependent difference in CD47 expression shields young cells but allows clearance of aging and damaged cells from the system.CD47 is overexpressed in cancer cells (11, 14, 15), and the CD47–signal regulatory protein alpha interaction is considered a major pathway of immune evasion by tumor cells (15). Administration of anti-CD47 antibodies enabled the phagocytosis of tumor cells in vitro, reduced their growth, and prevented the metastasis of human patient tumor cells (14). In this article, using the murine Plasmodium yoelii nonlethal model, we provide quantitative evidence for age of RBC as the basis for the survival and growth of malaria parasites and provide supporting data that suggest that P. yoelii nonlethal parasites prefer to grow inside younger RBC, which allows them to evade immune clearance by phagocytic cells through a CD47-mediated process, and that CD47 modulates the clearance of malaria infection. To our knowledge, this is the first report that provides a molecular basis for the age-dependent preference for infection of RBC by a Plasmodium parasite and sheds light on its implications for the severity of malaria infection in a host.  相似文献   
8.
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。  相似文献   
9.
目的了解岳阳汉族人群Kidd(Jka/Jkb)、Duffy(Fya/Fyb)、Diego(Dia/Dib)、Dombrock(Doa/Dob)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Fya=0.9472,Fyb=0.0528;Dombrock血型基因频率为Doa=0.0842,Dob=0.9158;Diego血型基因频率为Dia=0.0247,Dib=0.9752;Kidd血型基因频率为Jka=0.4802,Jkb=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。  相似文献   
10.
本文分析血细胞计数的影响因素,发现血细胞检测结果受环境温度、放置时间、采血方式等因素的影响,检验人员在采血和检测过程中应尽可能排除各种影响因素,为临床提供真实可靠的检验结果。  相似文献   
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