Current standards and the latest developments in the treatment of thalassaemia

Thalassaemia syndrome is an autosomal recessive inherited disease caused by impaired productions of the globin chains leading to chronic anaemia. In the last few decades, red blood cell transfusion, iron chelation therapy and allogeneic haematopoietic stem cell transplantation are three main treatment modalities in this disease. Advances in understanding the underlying basis of the thalassaemia disease have introduced several new innovative therapeutic approaches including modulating of erythropoiesis, modulating of iron metabolism and gene therapy. Preclinical studies of several novel therapeutic agents showed promising results. Currently, there are multiple ongoing clinical studies of these novel therapies in patients with thalassaemia. This review aims to summarize the key points of current standard treatment and the latest developments in the treatment of thalassaemia.     

Cardiomyocyte ultrastructural damage in β‐thalassaemic mice

β‐thalassaemia is a hereditary anaemia resulting from the absence or reduction in β‐globin chain production. Heart complications related to iron overload are the most serious cause of death in these patients. In this report cardiac pathology of β‐thalassaemic mice was evaluated by light and electron microscopy. The study was carried out in thalassaemic mice carrying human β‐thalassaemia mutation, IVSII‐654 (654), transgenic mice carrying human β^E‐globin transgene insertion (E4), thalassaemic mice with human β^E‐globin transgene insertion (654/E4) and homozygous thalassaemic mice rescued by the human β^E‐globin transgene (R), which is generated by cross‐breeding between the 654 and E4 mice. Histology showed iron deposition in cardiac myocytes of 654 and R mice, but the ultrastructural damage was observed only in the R mice when compared with the wild type, 654, E4 and 654/E4 mice. Histopathological changes in the cardiomyocytes of the R mice included mitochondrial swelling, loss of myofilaments and the presence of lipofuscin, related to the increased level of tissue iron content. The progressive ultrastructural pathology in R mice cardiomyocytes is consistent with the ultrastructural pathology previously studied in patients with thalassaemia. Thus, this R thalassaemic mouse model is suitable for in vivo pathophysiological study of thalassaemic heart.     

铁代谢对于β地中海贫血表型的修饰作用的研究进展

β地中海贫血(简称地贫)是由于β珠蛋白基因缺陷导致β珠蛋白肽链合成减少的遗传性溶血性疾病。其病理机制为α/β珠蛋白肽链比例严重失衡,多余的α珠蛋白链沉积形成包涵体,引发红细胞溶血、无效造血以及继发性多组织器官铁超载等。机体铁负荷过重可能导致生长发育停滞、肝硬化、心功能不全等并发症,加重其表型。近年来,随着机体铁代谢相关基因相继被发现,铁代谢在地贫的发生发展过程中的机理逐渐被阐明。研究人员通过改变铁调素、转铁蛋白受体等铁代谢关键基因的表达,揭示了限制红细胞铁应用可改善β地贫无效造血和铁过载的症状,为治疗地贫提供了一个新的途径。本文围绕铁代谢相关基因以及通路在β地贫中的研究进展进行综述。     

Canine packed red blood cell transfusions in Spain

Transfusion medicine is a relatively new and rapidly growing area of research in veterinary medicine. Packed red blood cell transfusion (PRBC) is indicated for treatment of symptomatic anemia resulting from hemorrhage, hemolysis, or ineffective erythropoiesis. The objective of this retrospective study was to identify clinical manifestations and underlying diseases of dogs that received PRBC and determine possible transfusion complications and outcome. Donors were blood typed and previously tested for infectious diseases potentially transmitted by transfusion (Ehrlichia canis, Borrelia burdogferi, Dirofilaria immitis, Anaplasma phagocytophila, Anaplasma platys, Babesia spp., Bartonella spp., and Rickettsia spp, and Leishmania infantum). Recipients were also blood typed and cross-matching was routinely performed before any transfusion. Packed cell volume (PCV) was performed before and after transfusion. Every PRBC transfusion was delivered by a bedside leukoreduction filter. Sixty-five PRBC transfusions were administered to 56 dogs. Twenty-two dogs resulted DEA 1.1 positive and 34 DEA 1.1 negative. Reasons for transfusion included anemia secondary to hemorrhage (n = 48; 74%), hemolysis (n = 8; 12%), and ineffective erythropoiesis (n = 9; 14%). Median PCV before transfusion was 14.7% (range: 7–36%) and the mean post-transfusion was 21% (range: 9–39%). Mean increase in PCV was 6.5%. Thirty-one (70%) dogs were discharged and 17 (30%) dogs died or were euthanized. Transient hyperthermia was the only adverse reaction found. PRBC transfusion for symptomatic treatment of anemia is a safe and useful procedure, if the transfusion is closely supervised throughout its duration.     

The Effectiveness of Sofosbuvir and Daclatasvir in the Treatment of Hepatitis C in Thalassaemia Major Patients and their Effect on Haematological Factors

Context: Patients with thalassaemia are at risk of infections such as hepatitis C virus (HCV) due to their repeated blood transfusions; meanwhile, the treatment of thalassaemia patients who had developed HCV infection is a controversial issue. Aims: Although the effectiveness of direct-acting antivirals on HCV infection has been confirmed, their side-effects as well as effects on haematological factors due to the resultant need for blood transfusion remain to be further understood. Materials and Methods: In this study, 61 patients with major beta thalassaemia and HCV infection, and who had a history of interferon treatment failure were examined. The patients underwent a 24-week treatment with sofosbuvir (SOF) and daclatasvir (DAC). Sustained virological response 12 was used to assess response to treatment. At the end of the study, the need for blood transfusion and serum ferritin was evaluated. Results: About 98.4% of the patients responded to the treatment, and only one patient with genotype 1b did not respond positively. No significant complications necessitating treatment cessation were observed, and all the patients tolerated the treatment well. The level of liver enzymes showed a significant reduction 12 weeks after the treatment. The need for blood transfusions in patients before treatment was averagely 1.595 ± 0.65 bag per month, in which 1.593 ± 0.64 bags were received after treatment (P = 0.9). This regimen did not affect the amount of anaemia in patients and did not differentiate the need for blood transfusions. The rate of haemoglobin before treatment was 9.5 ± 1.42 g/dl, which reached 9.6 ± 1.6 g/dl after treatment (P = 0.54). Ferritin levels decreased significantly (from 1948.08 ± 1539.54 to 1315.73 ± 1207.67 ng/ml) (P = 0.001) in the patients after the treatment. Conclusion: Combination of SOF and DAC is an effective and tolerable treatment regimen without affect on the amount of anaemia in patients and did not differentiate the need for blood transfusions.     

Morphological differentiation of severe aplastic anaemia from hypocellular refractory cytopenia of childhood: reproducibility of histopathological diagnostic criteria

Baumann I, Führer M, Behrendt S, Campr V, Csomor J, Furlan I, de Haas V, Kerndrup G, Leguit R J, De Paepe P, Noellke P, Niemeyer C & Schwarz S
(2012) Histopathology  61, 10–17 Morphological differentiation of severe aplastic anaemia from hypocellular refractory cytopenia of childhood: reproducibility of histopathological diagnostic criteria Aims: To evaluate the reproducibility and reliability of the histomorphological criteria differentiating severe aplastic anaemia (SAA) and hypoplastic refractory cytopenia of childhood (RCC), the most frequently acquired hypocellular bone marrow conditions of childhood. Methods and results: We performed a double‐blind interobserver study of 100 different cases of SAA and RCC among seven haematopathologists of the European Working Group of MDS in Childhood (EWOG‐MDS) and the German SAA study. Cases with foci of typical myelodysplastic syndrome (MDS) morphology, such as patchy erythropoiesis with defective maturation, in an otherwise highly hypocellular or adipocytic bone marrow were classified as having RCC. Bone marrow samples without a patchy distribution, few scattered myeloid cells or haematopoietic aplasia were diagnosed as SAA. In only four of 100 cases did the reference pathologists not reach agreement regarding classification as SAA or RCC. The kappa index was 0.79. Conclusions: Our results show that the vast majority of SAA and RCC cases can be reliably differentiated by morphological means alone. A clear differentiation between SAA and RCC at presentation is mandatory for optimizing therapy strategies, and might be responsible for the fact that, in the German childhood SAA study, the probability of developing clonal disease after immunosuppressive therapy has dropped to 3%.     

Anemia and transfusion of red blood cells

The red cells transfusion is a mainstay in the treatment of anemic patients. These blood transfusions are not without risks. The risk-benefit profile for red cell transfusions to treat anaemia is uncertain, but they may contribute to adverse patient outcomes in some situations. The ability of a patient to tolerate anaemia depends on their clinical condition and the presence of any significant co-morbidity; maintenance of circulating volume is of paramount importance. There is no universal transfusion trigger. Advances in the development and validation of physiological, accessible, practical and reliable markers to guide therapy are expected. To improve patients'' outcomes, further study is required to more fully explore the risk of anemia, optimal hemoglobin level, and the risk and efficacy of RBC transfusion. Future clinical investigations with high priority should determine the efficacy of transfusion in those classified as uncertain scenarios. In the absence of data, it is prudent that transfusion is administered with caution in these clinical scenarios.     

A comparative analysis across the globe: blood transfusion therapy in thalassaemia major

The major arms of the clinical management of thalassaemia major include life-long regular blood transfusion and iron chelation therapy – essential to address the consequences of the genetic defect, mainly the severe anaemia and the bone marrow hyperactivity. Effective blood transfusion therapy requires adequate and safe blood. However, the standards for both blood screening and blood transfusion practices vary depending on the geographical area, from country to country and even within the same country, between different regions and medical centres. The Thalassaemia International Federation (TIF), a patients’ parents-driven organization with 98 member thalassaemia or thalassaemia-related associations from 60 countries around the world, was established in 1987 with the mission to promote the quality of medical care and its access to every patient with thalassaemia across the world. An important activity contributing towards the fulfilment of its goals has been the establishment of an educational programme, in collaboration with the World Health Organization, with which in official relations since 1996. The educational programme that now enjoys international recognition focuses on providing awareness to the community at large and information and training to patients/parents and health professionals, and includes (i) preparation, publication, translation and distribution of educational books, leaflets and other material, (ii) the organization of local, national, regional and international conferences, workshops, seminars and field trips. In the context of TIF's educational programme, a survey has been conducted covering a period of 2 years, the aim of which was to evaluate the effectiveness of blood transfusion therapy in patients with thalassaemia major, in a number of affected countries around the world.     

Update on patient blood management 2019

Preoperative anaemia is common and is associated with adverse outcomes. Furthermore, it puts patients at risk for allogeneic blood transfusions which in turn may be associated with adverse outcomes. Diagnosis and treatment of anaemia is one of the tenets of patient blood management (PBM), along with reduction in unnecessary transfusions and use of hemostatic agents to reduce bleeding among multiple others. Effective PBM is multi‐disciplinary, multi‐modal, timely, personalized and patient‐centred. I will discuss recent updates in PBM with emphasis on treatment of preoperative anaemia, restrictive transfusion triggers and use of tranexamic acid. I will also briefly discuss the barriers to PBM implementation and start conversation about how to improve patient engagement.     

A Minimal Set of SNPs for the Noninvasive Prenatal Diagnosis of β‐Thalassaemia

β‐thalassaemia is one of the commonest autosomal recessive single‐gene disorders worldwide. Prenatal tests use invasive methods, posing a risk for the pregnancy itself. Development of a noninvasive prenatal diagnostic method is, therefore, of paramount importance. The aim of the present study is to identify high‐heterozygote informative single‐nucleotide polymorphisms (SNPs), suitable for the development of noninvasive prenatal diagnosis (NIPD) of β‐thalassaemia. SNP genotyping analysis was performed on 75 random samples from the Cypriot population for 140 SNPs across the β‐globin cluster. Shortlisted, highly heterozygous SNPs were then examined in 101 carrier families for their applicability in the noninvasive detection of paternally inherited alleles. Forty‐nine SNPs displayed more than 6% heterozygosity and were selected for NIPD analysis, revealing 72.28% of the carrier families eligible for qualitative SNP‐based NIPD, and 92% for quantitative detection. Moreover, inference of haplotypes showed predominant haplotypes and many subhaplotypes with sufficient prevalence for diagnostic exploitation. SNP‐based analyses are sensitive and specific for the detection of the paternally inherited allele in maternal plasma. This study provides proof of concept for this approach, highlighting its superiority to NIPD based on single markers and thus providing a blueprint for the general development of noninvasive prenatal diagnostic assays for β‐thalassaemia.     

Anaemia in persons with HIV infection: prognostic marker and contributor to morbidity

Human immunodeficiency virus (HIV)-infected patients experience a range of haematological complications including anaemia, neutropenia, lymphopenia and thrombocytopenia. Anaemia is a prognostic marker of future disease progression or death, independent of CD4 and viral load. Recovery from anaemia reduces the risk of disease progression to approximately the same level as seen among patients who have never had anaemia. Additionally, anaemia impacts a range of dimensions of quality of life, most commonly through fatigue. Anaemia can be caused by a range of mechanisms including infections, neoplasms, dietary deficiencies, blood loss and medication. Histologically, bone marrow hypoproliferation and dysplasia are the most commonly seen. Both AZT and d4T induce macrocytosis, however, AZT, but not d4T, has broader myelosuppressive effects both in vitro and in vivo. The management of anaemia typically includes correction of the underlying cause(s) and blood transfusion or erythropoietin. However, blood transfusions and iron supplementation may activate HIV expression and possibly worsen immunosuppression. Recombinant human erythropoietin (rHuEPO) is an effective means of improving haemoglobin and reducing transfusion requirements in patients who have low (< 500 IU/L) endogenous erythropoietin levels.     

Transfusion in Sickle cell disease: best practice and understanding of its utility

Transfusion therapy remains an important treatment modality for patients with sickle cell disease (SCD). Transfusions are given not only to treat symptomatic anaemia, but also to decrease SCD‐related complications by lowering the percentage of circulating sickle red cells, thus decreasing blood viscosity and vaso‐occlusion. The strongest evidence of the effectiveness of transfusion is in primary and secondary stroke prophylaxis, where transfusion reduces the risk of overt stroke by about 90–70%, and in pre‐operative transfusion, where transfusion reduces the risk of acute chest syndrome by at least 30%. Most other indications for transfusion in SCD are based on expert opinion or less well‐controlled studies. In this brief overview, we discuss methods of transfusion, the evidence and expert opinion regarding various indications in sickle cell disease and our current pathophysiologic understanding of how transfusions may work in SCD.     

Beta-thalassemia

Beta-thalassemia is caused by the reduced (beta⁺) or absent (beta⁰) synthesis of the beta globin chains of the hemoglobin tetramer. Three clinical and hematological conditions of increasing severity are recognized, i.e., the beta-thalassemia carrier state, thalassemia intermedia, and thalassemia major. The beta-thalassemia carrier state, which results from heterozygosity for beta-thalassemia, is clinically asymptomatic and is defined by specific hematological features. Thalassemia major is a severe transfusion-dependent anemia. Thalassemia intermedia comprehend a clinically and genotypically very heterogeneous group of thalassemia-like disorders, ranging in severity from the asymptomatic carrier state to the severe transfusion-dependent type. The clinical severity of beta-thalassemia is related to the extent of imbalance between the alpha and nonalpha globin chains. The beta globin (HBB) gene maps in the short arm of chromosome 11, in a region containing also the delta globin gene, the embryonic epsilon gene, the fetal A-gamma and G-gamma genes, and a pseudogene (ψB1). Beta-thalassemias are heterogeneous at the molecular level. More than 200 disease-causing mutations have been so far identified. The majority of mutations are single nucleotide substitutions, deletions, or insertions of oligonucleotides leading to frameshift. Rarely, beta-thalassemia results from gross gene deletion. In addition to the variation of the phenotype resulting from allelic heterogeneity at the beta globin locus, the phenotype of beta-thalassemia could also be modified by the action of genetic factors mapping outside the globin gene cluster and not influencing the fetal hemoglobin. Among these factors, the ones best delineated so far are those affecting bilirubin, iron, and bone metabolisms. Because of the high carrier rate for HBB mutations in certain populations and the availability of genetic counseling and prenatal diagnosis, population screening is ongoing in several at-risk populations in the Mediterranean. Population screening associated with genetic counseling was extremely useful by allowing couples at risk to make informed decision on their reproductive choices. Clinical management of thalassemia major consists in regular long-life red blood cell transfusions and iron chelation therapy to remove iron introduced in excess with transfusions. At present, the only definitive cure is bone marrow transplantation. Therapies under investigation are the induction of fetal hemoglobin with pharmacologic compounds and stem cell gene therapy.     

β-Thalassemia

β-Thalassemia is caused by reduced (β⁺) or absent (β⁰) synthesis of the β-globin chains of hemoglobin. Three clinical and hematological conditions of increasing severity are recognized: the β-thalassemia carrier state, thalassemia intermedia, and thalassemia major, a severe transfusion-dependent anemia. The severity of disease expression is related mainly to the degree of α-globin chain excess, which precipitates in the red blood cell precursors, causing both mechanic and oxidative damage (ineffective erythropoiesis). Any mechanism that reduces the number of unbound α-globin chains in the red cells may ameliorate the detrimental effects of excess α-globin chains. Factors include the inheritance of mild/silent β-thalassemia mutations, the coinheritance of α-thalassemia alleles, and increased γ-globin chain production. The clinical severity of β-thalassemia syndromes is also influenced by genetic factors unlinked to globin genes as well as environmental conditions and management. Transfusions and oral iron chelation therapy have dramatically improved the quality of life for patients with thalassemia major. Previously a rapidly fatal disease in early childhood, β-thalassemia is now a chronic disease with a greater life expectancy. At present, the only definitive cure is bone marrow transplantation. Therapies undergoing investigation are modulators of erythropoiesis and stem cell gene therapy.Genet Med advance online publication 03 November 2016     

Transfusion support for haemoglobinopathies

The indications and management of blood transfusion in the haemoglobinopathies have been reviewed. The sickle cell diseases that require transfusion support are sickle cell anaemia, sickle haemoglobin-C and -D diseases and sickle beta-thalassaemia. Homozygous beta-thalassaemia (Cooley's anaemia) is the major problem among the thalassaemias. The pathophysiology of the sickle cell disorders is largely based on the secondary effects of increased blood viscosity, whereas in the thalassaemias the defect is ineffective haematopoiesis. In the former the major problems occur as manifestations of vaso-occlusive crises with disseminated bone and abdominal pain, priapism, stroke and leg ulcers. Bone infarction and aseptic necrosis occur but the widespread bone changes, underdevelopment and haemochromatosis that complicate the thalassaemia are not prominent. Transfusion therapy in the sickle cell diseases is mainly episodic and is guided by the frequency of crises and the severity of vaso-occlusive complications. Partial exchange transfusion and the maintenance of haemoglobin A concentrations at 40 to 50 per cent is frequently indicated. In the thalassaemias, maintenance of haemoglobin levels is essential for normal growth and development. The problem of haemochromatosis is very serious. With hypertransfusion regimens the haemoglobin and haemotocrit are maintained above 12-13 g/dl and 35 per cent. The resulting benefit appears to be reduced blood volume, less iron turnover, and less intestinal iron absorption. The splenomegaly in these disorders is frequently associated with hypersplenism requiring well-timed splenectomy. Chronic and intensive chelation is necessary to prevent the ravages of iron overload. The availability of automated equipment for in vivo and ex vivo blood cell separation has brought new possibilities for improving the management of these haemoglobinopathies. It is feasible, but not as yet practical, to offer transfusions of neocytes (red cells with a mean age of 30 days) which have a 50 per cent longer survival than routine red cell preparations (mean age of 60 days). Neocytes can be prepared ex vivo from fresh routine blood donations using blood cell separator devices. The result is reduced transfusion requirements. A more recent suggestion for using the new technology is to remove the patient's oldest and most abnormal corpuscles on the basis of buoyant density and replacing them with neocytes . Thus the short-lived abnormal red cells would be removed before they could unload their iron. With automation it is possible to perform these procedures on an outpatient basis.     

Bone marrow and peripheral blood globin chain synthesis in sickle cell beta zero thalassaemia.

A similar imbalance of globin chain synthesis, with low non-alpha/alpha ratios, was shown in peripheral blood and in bone marrow of compound heterozygotes for both the Hb S and beta zero thalassaemia genes (S/beta zero thalassaemia). Previous purification of whole cell globin obtained from the bone marrow did not change the non-alpha/alpha ratio. The mean non-alpha/alpha ratios were 0.57 +/- 0.13 (means +/- SD) for the peripheral blood of 12 patients, 0.52 +/- 0.10 for five patients using bone marrow globin purified on Sephadex G100, and 0.55 +/- 0.16 for the unfiltered bone marrow globin of five patients. The data show that patients with S/beta zero thalassaemia have a similar beta chain deficiency in reticulocytes and in bone marrow cells, provided whole cell globin is used which avoids the removal of the free alpha chains. The non-alpha/alpha ratios in the peripheral blood of an S/beta zero thalassaemia patient and a beta thalassaemia heterozygote from the same family were compared in seven families and no significant difference was found.     

Effect of iron salts, haemosiderins, and chelating agents on the lymphocytes of a thalassaemia patient without chelation therapy as measured in the comet assay

Impairment of haemoglobin synthesis occurs in the genetic diseases known as thalassaemia. The consequent chronic anaemia leads to increased dietary iron absorption which results in iron overload. Treatment through regular blood transfusions increases oxygen capacity, but also adds iron from haemoglobin. An essential treatment, in parallel with transfusions, is the use of chelating agents to remove the excess iron. Thalassaemia patients are particularly at risk of free radical damage. Human lymphocytes from normal individuals can be investigated in vitro as a model system in the presence of free radicals in the Comet assay. This assay measures DNA damage, particularly DNA strand breakage. We examined cells from an Australian thalassaemic patient (sickle/beta thal double heterozygote-sickle phenotype) who had not yet received chelation therapy to determine if the cells were more sensitive to simulated iron overload and to haemosiderins. Lymphocytes from the patient were received as frozen samples after 28 h on dry ice and then placed in liquid nitrogen. Normal lymphocytes frozen under the same conditions and normal nonfrozen lymphocytes were compared. The lymphocytes from a normal female did not respond in vitro to ferric chloride (FeCl(3)) or haemosiderin but did to ferrous chloride (FeCl(2)) and ferrous sulphate (FeSO(4)). Deferoxamine appeared to reduce the response to FeCl(2) and FeSO(4) but deferiprone did not. When the lymphocytes from the nonchelated patient were treated with FeSO(4) and hydrogen peroxide, deferoxamine and deferiprone both reduced the response. Over the same dose range of iron salt (FeSO(4)), the lymphocytes from the thalassaemic patient were more sensitive, with much higher background levels of damage and induced damage. When deferiprone and deferoxamine were compared over a nontoxic range, deferiprone appeared to produce a greater reduction of damage in lymphocytes of the thalassaemia patient. Ferritin iron appears to be more available than haemosiderin iron in reactions leading to DNA damage. Haemosiderin containing higher amounts of the goethite-like (alpha-FeOOH) iron oxide phase leads to lower levels of DNA damage.     

Dominantly inherited beta thalassaemia intermedia caused by a new single nucleotide deletion in exon 2 of the beta globin gene: Hb morgantown (beta91 CTG>CG)

Family members in multiple generations of an Irish-American family were investigated for moderate to severe microcytic anaemia, inherited in an autosomal dominant fashion. A novel frameshift mutation of the beta globin gene was discovered. This study highlights the importance of considering dominantly inherited beta thalassemia in the investigation of anaemia, even in patients with ethnic backgrounds not usually associated with beta thalassaemia.     

Detection of erythroid hypoplasia in myelofibrosis using erythrokinetic studies.

The iron kinetic model described by Ricketts et al was used to study haemopoiesis in chronic myelofibrosis. The clearance of 59Fe-labelled transferrin from the plasma was analysed to quantify total, effective, and ineffective erythropoiesis, denoted by the terms marrow iron turnover (MIT), red cell iron turnover (RCIT), and per cent ineffective iron turnover (IIT%), respectively, in 12 cases of this disease. The patterns obtained were variable: values for MIT ranged from 24.4 to 510 mumol/l blood/day; those for RCIT from 0.4 to 119 mumol/l blood/day; and those for IIT% from 67 to 98%. One noteworthy feature was the presence in two cases of functional erythroid hypoplasia; these were characterised by severely reduced values for MIT (24.4 and 28 mumol/l blood/day) and RCIT (0.4 and 8 mumol/l blood/day.) A systematic study of the erythrokinetic features of myelofibrosis may indicate that erythroid hypoplasia is a more common cause of anaemia in this disease than has been previously recognised.