Hereditary red cell membrane defects: diagnostic and clinical aspects

Identification of a novel ANK1 gene variant c.1504-9G>A and its mechanism of intron retention in hereditary spherocytosis

Objective: The objective of this study was to pinpoint pathogenic genes and assess the mutagenic pathogenicity in two pediatric patients with hereditary spherocytosis. Methods: We utilized whole-exome sequencing (WES) for individual analysis (case 1) and family-based trio analysis (case 2). The significance of the intronic mutation was validated through a Minigene splicing assay and supported by subsequent in vitro experiments. Results: Both probands received a diagnosis of hereditary spherocytosis. WES identified a novel ANK1 c.1504-9G>A mutation in both patients, causing the retention of seven nucleotides at the 5' end of intron 13, as substantiated by the Minigene assay. This variant results in a premature stop codon and the production of a truncated protein. In vitro studies indicated a reduced expression of the ANK1 gene. Conclusion: The novel ANK1 c.1504-9G>A variant is established as the causative factor for hereditary spherocytosis, with the c.1504-9G site functioning as a splicing receptor.

Targeted next-generation sequencing identifies novel deleterious variants in ANK1 gene causing severe hereditary spherocytosis in Indian patients: expanding the molecular and clinical spectrum

Hereditary Spherocytosis (HS) is a common cause of hemolytic anemia varying from mild to severe hemolysis due to defects in red cell membrane protein genes, namely ANK1, SPTB, SPTA1, SLC4A1, and EPB42. These genes are considerably very large spaning 40-50 exons making gene-by-gene analysis costly and laborious by conventional methods. In this study, we explored 26 HS patients harboring 21 ANK1 variants identified by next-generation sequencing (NGS), characteristics and spectrum of the detected ANK1variants were analyzed in this study. Clinically, all the HS patients showed moderate to severe transfusion-dependent hemolytic anemia, some requiring splenectomy. We identified 13 novel and 8 reported variants, mainly 9 frameshifts, 2 missense, 6 nonsense, and 4 splice site ANK1 variants, using NGS technology. Frameshifts were remarkably the most common variant type seen in Indian HS patients with ANK1 gene defects. We have also explored expression levels of red cell membrane ankyrin protein by flow cytometry in 14 HS patients with ANK1 gene defects and a significant reduction in ankyrin protein expression has been found. This report mainly illustrates the molecular and phenotypic heterogeneity of ANK1 variants causing HS in Indian patients. Ankyrin-1 mutations are a significant cause of loss of function in dominant HS in the Indian population. Comprehensive genetic and phenotypic evaluation assists in implementing the knowledge of genetic patterns and spectrum of ANK1 gene variants, providing molecular support for HS diagnosis.

Screening for hereditary spherocytosis in daily practice: what is the best algorithm using erythrocyte and reticulocyte parameters?

Hereditary spherocytosis (HS) is the most common inherited chronic haemolytic anaemia in Northern Europe. During the last decade, additional erythrocyte and reticulocyte parameters have been developed on last-generation haematology analysers, leading to many publications about their effectiveness as a HS screening tool. For the first time on an independent cohort, we evaluated and compared the effectiveness of six published algorithms for the screening of HS using the UniCel DxH800 (Beckman-Coulter) and the XN-9000 (Sysmex) and determined which algorithm could be the most suitable in our daily clinical practice. A total of 95 EDTA samples were analysed prospectively on both haematology analysers. These included 11 confirmed HS patients and 84 non-HS patients. The specific reticulocyte parameters used on the DxH800 were mean reticulocyte volume, immature reticulocyte fraction and mean sphered cell volume, and on the XN-9000 were hypohaemoglobinised erythrocytes, microcytic erythrocytes and immature reticulocyte fraction. The three algorithms using parameters specific to Beckman-Coulter analysers provided a sensitivity of 100% with various specificities, ranging from 7.1 to 73.8%. The three algorithms published based on the parameters specific to Sysmex showed much lower performances, i.e. out of the 11 patients with HS, between one to five patients were screened as negative for HS. However, 100% sensitivity and specificity were reached using the EMA binding test concomitantly with those three algorithms. The algorithms using reticulocyte and erythrocyte parameters offered by the recent analysers are promising options as a HS first-tier screening tool. Nevertheless, they must be evaluated by each laboratory on their own analyser before implementation.

A novel SPTB mutation causes hereditary spherocytosis via loss-of-function of β-spectrin

Hereditary spherocytosis (HS) is the most frequently observed chronic non-immune hemolytic disorder caused by altered red cell membrane function. SPTB gene mutation is one of the most common causes of HS, but pathogenicity analyses and pathogenesis research on these mutations have not been widely conducted. In this study, a novel heterozygous mutation of the SPTB gene (c.1509_1518del; p.K503Nfs*67) was identified in a Chinese family with HS by whole-exome sequencing (WES) and was then confirmed by Sanger sequencing. Next, the pathogenicity and pathogenesis of this mutation were studied using peripheral blood. We found that this mutation disrupted the synthesis and localization of β-spectrin and weakened the interaction between β-spectrin and ankyrin, which may be caused by the nonsense-mediated mRNA degradation pathway. These changes lead to the transformation of discoid erythrocytes into spherocytes, resulting in hemolytic anemia. Therefore, we classified this novel mutation as a pathogenic mutation leading to loss-of-function of β-spectrin. It would be insightful to perform the same mutation test and to provide genetic counseling to other relatives of the proband. Our study increases the current understanding of the molecular mechanisms related to mutations in SPTB.

Clinical manifestation and phenotypic analysis of novel gene mutation in 28 Chinese children with hereditary spherocytosis

Purpose

Objective to summarize the clinical features and laboratory findings of 28 Chinese children with hereditary spherocytosis (HS), and analyze these mutations.

Method

Collected and analyzed the clinical data of all children and their parents, and completed the relevant laboratory examinations of all children. Analyzed the sequence of related genes by second‐generation sequencing technology, and verified the suspected mutations by Sanger sequencing method. Analyzed all biological information using the Single Nucleotide Polymorphism database, the 1000 Human Genome Project, and the Exosome Aggregation Consortium.

Result

New mutations were detected in the HS coding region of 28 children. Among them, there were 13 cases (46.4%) with ANK1 mutation, 10 cases (35.7%) with SPTB mutation, three cases (10.7%) with SLC4A1 mutation, and two cases (7.2%) with SPTA1 mutation. All mutations cause amino acid changes in the coding gene, as well as subsequent changes in protein structure or loss of function.

Conclusion

All the newly discovered gene coding region mutation sites detected are the suspected pathogenic causes of the 28 Chinese children. At the same time, the second‐generation gene sequencing technology is an effective means to diagnose HS. Different mutation types and different mutation regions have no significant correlation with the severity of anemia. The novel gene mutation sites in 28 children studied in this paper have not yet been included in the human genome database, dbSNP (v138), or ExAC database. The new gene mutations found in HS children can provide a theoretical basis for further exploring the genetic causes of HS in Chinese children.

A novel SPTB gene mutation in neonatal hereditary spherocytosis: A case report

The aim of the present study was to enhance the understanding of the diagnosis and treatment of neonatal hereditary spherocytosis (HS). Gene sequencing and analysis was performed for the crucial splicing signals on the exons and introns of the 302 known pathogenic genes [including ANK1, SPTAN1, SPTA1, EPB42, SLC4A1, and SPTB] that are associated with this genetic deficiency of erythrocytes. A 26-day-old female presented with jaundice, anemia, an increased count in peripheral blood reticulocyte and spherocytes and a positive acidified glycerol hemolysis test. Gene sequencing revealed a novel mutation of c.3737delA (p.Lys1246fs) in the exon 16 of SPTB (14q23|NM_000347.5) gene in the patient and her father. The mutation was a frame-shifting mutation, which may result in the truncation of β-haemoglobin in the erythrocyte membrane can lead to loss of normal function, leading to the occurrence of diseases, including jaundice and hemolytic anemia. For neonates with jaundice and anemia, family history, erythrocyte index and peripheral blood smear findings have been indicated to contribute to the diagnosis of HS. In the current study, gene sequencing was indicated to be helpful for the diagnosis of HS. A novel mutation of SPTB gene was identified, which may be pathogenic via modulating the activity of β-spectrin in the erythrocyte membrane.

Aberrant Membrane Composition and Biophysical Properties Impair Erythrocyte Morphology and Functionality in Elliptocytosis

Red blood cell (RBC) deformability is altered in inherited RBC disorders but the mechanism behind this is poorly understood. Here, we explored the molecular, biophysical, morphological, and functional consequences of α-spectrin mutations in a patient with hereditary elliptocytosis (pEl) almost exclusively expressing the Pro260 variant of SPTA1 and her mother (pElm), heterozygous for this mutation. At the molecular level, the pEI RBC proteome was globally preserved but spectrin density at cell edges was increased. Decreased phosphatidylserine vs. increased lysophosphatidylserine species, and enhanced lipid peroxidation, methemoglobin, and plasma acid sphingomyelinase (aSMase) activity were observed. At the biophysical level, although membrane transversal asymmetry was preserved, curvature at RBC edges and rigidity were increased. Lipid domains were altered for membrane:cytoskeleton anchorage, cholesterol content and response to Ca²⁺ exchange stimulation. At the morphological and functional levels, pEl RBCs exhibited reduced size and circularity, increased fragility and impaired membrane Ca²⁺ exchanges. The contribution of increased membrane curvature to the pEl phenotype was shown by mechanistic experiments in healthy RBCs upon lysophosphatidylserine membrane insertion. The role of lipid domain defects was proved by cholesterol depletion and aSMase inhibition in pEl. The data indicate that aberrant membrane content and biophysical properties alter pEl RBC morphology and functionality.

The Effect of Bee Venom Peptides Melittin, Tertiapin, and Apamin on the Human Erythrocytes Ghosts: A Preliminary Study

Red blood cells (RBCs) are the most abundant cells in the human blood that have been extensively studied under morphology, ultrastructure, biochemical and molecular functions. Therefore, RBCs are excellent cell models in the study of biologically active compounds like drugs and toxins on the structure and function of the cell membrane. The aim of the present study was to explore erythrocyte ghost’s proteome to identify changes occurring under the influence of three bee venom peptides-melittin, tertiapin, and apamin. We conducted preliminary experiments on the erythrocyte ghosts incubated with these peptides at their non-hemolytic concentrations. Such preparations were analyzed using liquid chromatography coupled with tandem mass spectrometry. It was found that when higher concentrations of melittin and apamin were used, fewer proteins were identified. Moreover, the results clearly indicated that apamin demonstrates the greatest influence on the RBCs ghosts proteome. Interestingly, the data also suggest that tertiapin exerted a stabilizing effect on the erythrocyte membrane. The experiments carried out show the great potential of proteomic research in the projects focused on the toxin’s properties as membrane active agents. However, to determine the specificity of the effect of selected bee venom peptides on the erythrocyte ghosts, further proteomic research should be focused on the quantitative analysis.

Identification of new mutations in patients with hereditary spherocytosis by next-generation sequencing

Hereditary spherocytosis (HS) is the most common inherited hemolytic anemia characterized by the presence of spherical-shaped erythrocytes on the peripheral blood smear, hemolysis, splenomegaly, jaundice, and gallstones. To date, mutations in at least five genes (ANK1, EPB42, SLC4A1, SPTA1, and SPTB) have been found to be associated with different subtypes of HS. Here, we aim to investigate the presence of novel as well as known mutations in 35 Chinese patients with clinically suspected HS. Whole-exome sequencing (WES) has identified 3 patients with SLC4A1, 16 patients with ANK1, and 16 patients with SPTB mutations, including 5 splicing, 12 nonsense, 9 frameshift, 7 missense, and 1 start-loss mutation, indicating that SPTB and ANK1 are the most frequently mutated genes in Chinese HS patients. Among 34 mutations identified, 21 were novel. Most of SPTB and ANK1 mutations were nonsense (8/16) and frameshift (6/16) mutations. By trio analysis of eight families we have confirmed six de novo mutations. In addition, genotype-phenotype analysis was also performed by comparing clinical manifestations among three groups of patients with SPTB, ANK1, and SLC4A1 mutations. It revealed that patients with ANK1 mutations had a significantly higher level of MCV and MCH but lower percentage of spherocytes compared with those carrying SPTB mutations. In conclusion, our results suggested that molecular diagnosis by next-generation sequencing (NGS) is a fast, economic, and accurate way to detect and identify pathogenic alterations of inherited diseases, highlighting the potential usage of NGS in clinical practice.

Clinical utility of targeted gene enrichment and sequencing technique in the diagnosis of adult hereditary spherocytosis

Background

The present study aimed to use the targeted capture and sequencing technique to diagnose adult hereditary spherocytosis (HS). These results were compared with clinical features and laboratory examinations to explore the diagnosis of HS.

Methods

Whole blood and clinical data from ten patients with HS were collected. Genomic DNA was extracted, and a library was prepared. Exomes of patients with ten HS-related genes encoding red cell membrane skeleton protein were captured and sequenced. Bioinformatics analyses were carried out throughout the 1000 Genomes Project, ExAC, dbSNP147, and 1000 Normal Han Population databases.

Results

Gene mutations were found in 9 out of 10 cases of HS. Our data validation showed 90% specificity. Three types of gene mutations were found, including 6 cases of SPTB, 3 cases of ANK1, and 2 cases of SLC4A1. There were 4 mutation forms, including nonsense mutation, missense mutation, shear mutation, and code shift mutation, all of which were new, heterozygous mutations. These variations were predicted to be pathogenic in four databases.

Conclusions

Our data demonstrate that targeted gene enrichment and sequencing methods were an efficient tool for determining genetic etiologies of red blood cell (RBC) membrane disorders and can facilitate accurate diagnosis and genetic counseling. They are also in good agreement with the clinical results.

Molecular diagnosis of hereditary spherocytosis by multi-gene target sequencing in Korea: matching with osmotic fragility test and presence of spherocyte

Background

Current diagnostic tests for hereditary spherocytosis (HS) focus on the detection of hemolysis or indirectly assessing defects of membrane protein, whereas direct methods to detect protein defects are complicated and difficult to implement. In the present study, we investigated the patterns of genetic variation associated with HS among patients clinically diagnosed with HS.

Methods

Multi-gene targeted sequencing of 43 genes (17 RBC membrane protein-encoding genes, 20 RBC enzyme-encoding genes, and six additional genes for the differential diagnosis) was performed using the Illumina HiSeq platform.

Results

Among 59 patients with HS, 50 (84.7%) had one or more significant variants in a RBC membrane protein-encoding genes. A total of 54 significant variants including 46 novel mutations were detected in six RBC membrane protein-encoding genes, with the highest number of variants found in SPTB (n = 28), and followed by ANK1 (n = 19), SLC4A1 (n = 3), SPTA1 (n = 2), EPB41 (n = 1), and EPB42 (n = 1). Concurrent mutations of genes encoding RBC enzymes (ALDOB, GAPDH, and GSR) were detected in three patients. UGT1A1 mutations were present in 24 patients (40.7%). Positive rate of osmotic fragility test was 86.8% among patients harboring HS-related gene mutations.

Conclusions

This constitutes the first large-scaled genetic study of Korean patients with HS. We demonstrated that multi-gene target sequencing is sensitive and feasible that can be used as a powerful tool for diagnosing HS. Considering the discrepancies of clinical and molecular diagnoses of HS, our findings suggest that molecular genetic analysis is required for accurate diagnosis of HS.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1070-0) contains supplementary material, which is available to authorized users.

[Clinical and genetic features of children with hereditary spherocytosis: an analysis of 4 cases]

Four children (two boys and two girls), aged from 3 years and 7 months to 5 years, had mild or moderate anemia, mild hepatosplenomegaly, jaundice (mainly an increase in indirect bilirubin), an increase in the percentages of reticulocytes and spherical erythrocytes in peripheral blood smear and an increase in erythrocyte osmotic brittleness. High-throughput sequencing found two novel mutations in the SLC4A1 gene, c.37G>A and c.340T>C, in case 1 and case 2 respectively, and these two mutations were predicted to be pathogenic by Mutation Taster. The Polyphen2 scores of these two mutations were 0.87 and 0.83 respectively, which suggested that these mutations were probably damaging. The SIFT scores of these two mutations were 0.008 and 0.09 respectively, suggesting that these mutations were probably damaging. No abnormality in this gene was found in their parents. Two reported heterozygous mutations in the ANK1 gene, c.830A>G and c.985G>C, were found in case 3 and case 4 respectively. Gene detection was not performed for the parents of case 3. The mother of case 4 was diagnosed with hereditary spherocytosis and had a heterozygous mutation of c.985G>C in the ANK1 gene. All four children were diagnosed with hereditary spherocytosis. Case 3 had a hemoglobin level of <80 g/L and underwent splenectomy at the age of 5 years and 6 months, and regular postoperative reexamination showed a hemoglobin level of >105 g/L. Hereditary spherocytosis is a hereditary hemolytic disease caused by abnormality in erythrocyte membrane protein, and gene detection helps to make a confirmed diagnosis.

Novel compound heterozygous SPTA1 mutations in a patient with hereditary elliptocytosis

Hereditaryelliptocytosis (HE) is a hereditary hemolytic disease, characterized by the presence of many elliptical erythrocytes in the peripheral blood that is caused by abnormal cytoskeletal proteins in the erythrocyte membrane. In the present study, a novel, causal HE mutation was reported. Routine blood examinations were performed on the proband and their family, and the fluorescence intensity of eosin‑5‑maleimide (EMA)‑labeled erythrocytes was determined via flow cytometry. Subsequently, DNA was extracted from the peripheral blood of the proband and their family members, and amplified by quantitative polymerase chain reaction. The Sanger sequencing approach was used to determine and identify gene mutations, which were verified by matrix‑assisted laser desorption‑ionization time of flight (MALDI‑TOF) mass spectrometry. To exclude genetic polymorphisms, newly identified mutations were subjected to large‑scale gene screening using high‑resolution melt analysis. Protein expression levels in the erythrocyte membrane of the proband were determined via SDS‑PAGE, which demonstrated that, compared with healthy controls, the proband exhibited a reduction in EMA‑labeled erythrocytes. In addition, DNA analysis demonstrated that the proband carried three mutations in the spectrin α chain erythrocytic 1 (SPTA1) gene: c.161A>C, c.5572C>G and 6531‑12C>T. The corresponding mutant polypeptides were also analyzed by MALDI‑TOF mass spectroscopy. SDS‑PAGE analysis indicated that the proband exhibited normal levels of erythrocyte membrane proteins. In the present study, a novel HE case with a His54Pro mutation in the SPTA1 gene was reported. The results suggested that the His54Pro mutation influenced the role of erythrocyte membrane proteins without reducing its level of expression.

A robust mass spectrometry method for rapid profiling of erythrocyte ghost membrane proteomes

Background

Red blood cell (RBC) physiology is directly linked to many human disorders associated with low tissue oxygen levels or anemia including chronic obstructive pulmonary disease, congenital heart disease, sleep apnea and sickle cell anemia. Parasites such as Plasmodium spp. and phylum Apicomplexa directly target RBCs, and surface molecules within the RBC membrane are critical for pathogen interactions. Proteomics of RBC membrane ‘ghost’ fractions has therefore been of considerable interest, but protocols described to date are either suboptimal or too extensive to be applicable to a larger set of clinical cohorts.

Methods

Here, we describe an optimised erythrocyte isolation protocol from blood, tested for various storage conditions and explored using different fractionation conditions for isolating ghost RBC membranes. Liquid chromatography mass spectrometry (LC–MS) analysis on a Q-Exactive Orbitrap instrument was used to profile proteins isolated from the comparative conditions. Data analysis was run on the MASCOT and MaxQuant platforms to assess their scope and diversity.

Results

The results obtained demonstrate a robust method for membrane enrichment enabling consistent MS based characterisation of > 900 RBC membrane proteins in single LC–MS/MS analyses. Non-detergent based membrane solubilisation methods using the tissue and supernatant fractions of isolated ghost membranes are shown to offer effective haemoglobin removal as well as diverse recovery including erythrocyte membrane proteins of high and low abundance.

Conclusions

The methods described in this manuscript propose a medium to high throughput framework for membrane proteome profiling by LC–MS of potential applicability to larger clinical cohorts in a variety of disease contexts.

Electronic supplementary material

The online version of this article (10.1186/s12014-018-9190-4) contains supplementary material, which is available to authorized users.

The role of the red blood cell in host defence against falciparum malaria: an expanding repertoire of evolutionary alterations

The malaria parasite has co-evolved with its human host as each organism struggles for resources and survival. The scars of this war are carried in the human genome in the form of polymorphisms that confer innate resistance to malaria. Clinical, epidemiological and genome-wide association studies have identified multiple polymorphisms in red blood cell (RBC) proteins that attenuate malaria pathogenesis. These include well-known polymorphisms in haemoglobin, intracellular enzymes, RBC channels, RBC surface markers, and proteins impacting the RBC cytoskeleton and RBC morphology. A better understanding of how changes in RBC physiology impact malaria pathogenesis may uncover new strategies to combat the disease.

Recommendations regarding splenectomy in hereditary hemolytic anemias

Hereditary hemolytic anemias are a group of disorders with a variety of causes, including red cell membrane defects, red blood cell enzyme disorders, congenital dyserythropoietic anemias, thalassemia syndromes and hemoglobinopathies. As damaged red blood cells passing through the red pulp of the spleen are removed by splenic macrophages, splenectomy is one possible therapeutic approach to the management of severely affected patients. However, except for hereditary spherocytosis for which the effectiveness of splenectomy has been well documented, the efficacy of splenectomy in other anemias within this group has yet to be determined and there are concerns regarding short- and long-term infectious and thrombotic complications. In light of the priorities identified by the European Hematology Association Roadmap we generated specific recommendations for each disorder, except thalassemia syndromes for which there are other, recent guidelines. Our recommendations are intended to enable clinicians to achieve better informed decisions on disease management by splenectomy, on the type of splenectomy and the possible consequences. As no randomized clinical trials, case control or cohort studies regarding splenectomy in these disorders were found in the literature, recommendations for each disease were based on expert opinion and were subsequently critically revised and modified by the Splenectomy in Rare Anemias Study Group, which includes hematologists caring for both adults and children.

[Application of systematic etiological analysis in final and differential diagnosis of hereditary hemolytic anemia]

目的

探讨溶血病因系统分析策略在遗传性溶血性贫血病因诊断和鉴别诊断中的应用。

方法

以溶血病因系统分析方法对疑诊溶血性贫血的1 506例患者进行分析。

结果

①1 506例疑诊溶血性贫血患者中，男799例，女707例，中位年龄22岁（4 d~86岁）。涉及三大遗传性溶血病因的患者共1 413例（94%），其中单一病因溶血1 044例（74%），复合型溶血369例（26%）。②在涉及三大遗传性溶血病因的患者中，单一病因血红蛋白病、红细胞膜病及红细胞酶病分别为235例（22%）、656例（63%）及153例（15%）。单一溶血病因与复合溶血病因合并统计，涉及血红蛋白病、红细胞膜病及红细胞酶病分别为489例（29%）、948例（57%）及239例（14%）。上述两种基数统计的三大遗传性溶血病因构成比差异均无统计学意义（P值均>0.05）。③369例（26%）复合型溶血中，不同类型遗传缺陷以血红蛋白病合并红细胞膜病最常见（50%，184/369），亦见于红细胞酶病合并红细胞膜病（18%，66/369），血红蛋白病合并红细胞酶病（4%，13/369）。相同类型遗传缺陷复合型血红蛋白病、复合型膜病、复合型酶病分别为29例（8%）、57例（15%）、9例（2%）。其他复合型溶血、贫血、黄疸占3%（11例），见于合并后天因素、继发因素及其他系统异常。

结论

三大遗传性溶血病因同期检查能对94％的患者进行分类，常见的遗传性溶血病因依次为红细胞膜病、血红蛋白病和红细胞酶病。复合型溶血并非少见，仅单一因素分析不足以提供充分确诊依据。

Topological Structures and Membrane Nanostructures of Erythrocytes after Splenectomy in Hereditary Spherocytosis Patients via Atomic Force Microscopy

Hereditary spherocytosis is an inherited red blood cell membrane disorder resulting from mutations of genes encoding erythrocyte membrane and cytoskeletal proteins. Few equipments can observe the structural characteristics of hereditary spherocytosis directly expect for atomic force microscopy In our study, we proved atomic force microscopy is a powerful and sensitive instrument to describe the characteristics of hereditary spherocytosis. Erythrocytes from hereditary spherocytosis patients were small spheroidal, lacking a well-organized lattice on the cell membrane, with smaller cell surface particles and had reduced valley to peak distance and average cell membrane roughness vs. those from healthy individuals. These observations indicated defects in the certain cell membrane structural proteins such as α- and β-spectrin, ankyrin, etc. Until now, splenectomy is still the most effective treatment for symptoms relief for hereditary spherocytosis. In this study, we further solved the mysteries of membrane nanostructure changes of erythrocytes before and after splenectomy in hereditary spherocytosis by atomic force microscopy. After splenectomy, the cells were larger, but still spheroidal-shaped. The membrane ultrastructure was disorganized and characterized by a reduced surface particle size and lower than normal Ra values. These observations indicated that although splenectomy can effectively relieve the symptoms of hereditary spherocytosis, it has little effect on correction of cytoskeletal membrane defects of hereditary spherocytosis. We concluded that atomic force microscopy is a powerful tool to investigate the pathophysiological mechanisms of hereditary spherocytosis and to monitor treatment efficacy in clinical practices. To the best of our knowledge, this is the first report to study hereditary spherocytosis with atomic force microscopy and offers important mechanistic insight into the underlying role of splenectomy.

Delivery of drugs bound to erythrocytes: new avenues for an old intravascular carrier

For several decades, researchers have used erythrocytes for drug delivery of a wide variety of therapeutics in order to improve their pharmacokinetics, biodistribution, controlled release and pharmacodynamics. Approaches include encapsulation of drugs within erythrocytes, as well as coupling of drugs onto the red cell surface. This review focuses on the latter approach, and examines the delivery of red blood cell (RBC)-surface-bound anti-inflammatory, anti-thrombotic and anti-microbial agents, as well as RBC carriage of nanoparticles. Herein, we discuss the progress that has been made in surface loading approaches, and address in depth the issues relevant to surface loading of RBC, including intrinsic features of erythrocyte membranes, immune considerations, potential surface targets and techniques for the production of affinity ligands.

Mean corpuscular volume of control red blood cells determines the interpretation of eosin-5'-maleimide (EMA) test result in infants aged less than 6 months

Eosin-5′-maleimide (EMA) binding test is a flow cytometric test used to detect hereditary spherocytosis (HS). To perform the test sample from patients, 5–6 reference samples of red blood are needed. Our aim was to investigate how the mean corpuscular volume (MCV) of red blood cells influences on the value of fluorescence of bounded EMA dye and how the choice of reference samples affects the test result. EMA test was performed in peripheral blood from 404 individuals, including 31 children suffering from HS. Mean fluorescence channel of EMA-RBCs was measured with Cytomics FC500 flow cytometer. Mean corpuscular volume of RBCs was assessed with LH750 Beckman Coulter. Statistical analysis was performed using Graph Pad Prism. The correlation Spearman coefficient between mean channel of fluorescence of EMA-RBCs and MCV was r = 0.39, p < 0.0001. Interpretation of EMA test depends on MCV of the reference samples. If reference blood samples have lower MCV than the patients MCV, EMA test result might be negative. Due to different MCV values of RBCs in infancy and ca. Three months later, EMA test in neonates might be interpreted falsely negative. Samples from children younger than 3 months old had EMA test result 86.1 ± 11.7 %, whereas same samples that analyzed 4.1 ± 2.1 later had results of 75.4 ± 4.5 %, p < 0.05. Mean fluorescence of EMA-bound RBC depends on RBC’s volume. MCV of reference samples affects EMA test results; thus, we recommend selection of reference samples with MCV in range of ±2 fL compared to MCV of patient RBC’s.

The coincidence of familial mediterranean Fever and hypereosinophilia in a patient with hereditary elliptocytosis

Familial Mediterranean fever (FMF) is a genetic disease with autosomal inheritance characterized by recurrent fever, abdominal pain, and serositis attacks. It is relatively common in the races and ethnical groups around Mediterranean Sea (Sephardic Jews, Armenians, Turks and Arabians). Hereditary elliptocytosis (HE) is common genetic defect of the red blood cell membrane skeleton. Spectrin mutations are the predominant causes of HE. Hypereosinophilia is defined as a number of eosinophil granulocytes equal or greater than 0.5 × 10(9)/L of circulating blood. The main causes are allergies and parasitic infections. This case report describes a Turkish female HE patient who presented with FMF and hypereosinophilia. Genetic analysis revealed heterozygous mutation in exon 10 of the MEFV gene (V726A). The patient was successfully treated with colchicine and steroid treatment at 3-month follow-up. To the best of our knowledge, this is the first report of association between FMF, HE, and hypereosinophilia.

Hereditary spherocytosis: Consequences of delayed diagnosis

Objective:

To determine whether patients with undiagnosed hereditary spherocytosis hospitalized for transfusions might have avoided hospitalization via earlier diagnosis.

Study design:

Charts of all (N = 30) patients with hereditary spherocytosis seen in pediatric hematology at West Virginia University-Charleston were reviewed. Family and transfusion history and presence of neonatal jaundice were recorded. Complete blood count and reticulocyte values during infancy were available for 20 of 30 patients, while baseline steady-state values were available for all 30.

Results:

Transfusions were given to 22 patients; 12 of 14 with an aplastic crisis were undiagnosed. In 10 of 12, the severity of anemia led to hospitalization (3 to intensive care). All 10 had prior mean corpuscular hemoglobin concentration and/or red cell distribution width elevations and a history of neonatal jaundice; 7 of 10 had a positive family history.

Conclusions:

Undiagnosed hereditary spherocytosis may lead to inpatient transfusions for severe anemia. Earlier detection of hereditary spherocytosis is easily achievable and may reduce hospitalizations via closer monitoring.

Spectrin and phospholipids - the current picture of their fascinating interplay

The spectrin-based membrane skeleton is crucial for the mechanical stability and resilience of erythrocytes. It mainly contributes to membrane integrity, protein organization and trafficking. Two transmembrane protein macro-complexes that are linked together by spectrin tetramers play a crucial role in attaching the membrane skeleton to the cell membrane, but they are not exclusive. Considerable experimental data have shown that direct interactions between spectrin and membrane lipids are important for cell membrane cohesion. Spectrin is a multidomain, multifunctional protein with several distinctive structural regions, including lipid-binding sites within CH tandem domains, a PH domain, and triple helical segments, which are excellent examples of ligand specificity hidden in a regular repetitive structure, as recently shown for the ankyrin-sensitive lipid-binding domain of beta spectrin. In this review, we summarize the state of knowledge about interactions between spectrin and membrane lipids.

Erythrocyte shape abnormalities, membrane oxidative damage, and β-actin alterations: an unrecognized triad in classical autism

Autism spectrum disorders (ASDs) are a complex group of neurodevelopment disorders steadily rising in frequency and treatment refractory, where the search for biological markers is of paramount importance. Although red blood cells (RBCs) membrane lipidomics and rheological variables have been reported to be altered, with some suggestions indicating an increased lipid peroxidation in the erythrocyte membrane, to date no information exists on how the oxidative membrane damage may affect cytoskeletal membrane proteins and, ultimately, RBCs shape in autism. Here, we investigated RBC morphology by scanning electron microscopy in patients with classical autism, that is, the predominant ASDs phenotype (age range: 6–26 years), nonautistic neurodevelopmental disorders (i.e., “positive controls”), and healthy controls (i.e., “negative controls”). A high percentage of altered RBCs shapes, predominantly elliptocytes, was observed in autistic patients, but not in both control groups. The RBCs altered morphology in autistic subjects was related to increased erythrocyte membrane F₂-isoprostanes and 4-hydroxynonenal protein adducts. In addition, an oxidative damage of the erythrocyte membrane β-actin protein was evidenced. Therefore, the combination of erythrocyte shape abnormalities, erythrocyte membrane oxidative damage, and β-actin alterations constitutes a previously unrecognized triad in classical autism and provides new biological markers in the diagnostic workup of ASDs.

Zebrafish erythropoiesis and the utility of fish as models of anemia

Erythrocytes contain oxygen-carrying hemoglobin to all body cells. Impairments in the generation of erythrocytes, a process known as erythropoiesis, or in hemoglobin synthesis alter cell function because of decreased oxygen supply and lead to anemic diseases. Thus, understanding how erythropoiesis is regulated during embryogenesis and adulthood is important to develop novel therapies for anemia. The zebrafish, Danio rerio, provides a powerful model for such study. Their small size and the ability to generate a large number of embryos enable large-scale analysis, and their transparency facilitates the visualization of erythroid cell migration. Importantly, the high conservation of hematopoietic genes among vertebrates and the ability to successfully transplant hematopoietic cells into fish have enabled the establishment of models of human anemic diseases in fish. In this review, we summarize the current progress in our understanding of erythropoiesis on the basis of zebrafish studies and highlight fish models of human anemias. These analyses could enable the discovery of novel drugs as future therapies.