Thalassaemia Registries: A Call for Action. A Position Statement from the Thalassaemia International Federation

Disease registries can be extremely powerful evidence generating tools while providing a central meeting point for all implicated stakeholders, facilitating their networking and interaction. Registries can play a major role in addressing the challenges that the care of thalassemia patients is currently facing. By collecting updated and representative data on disease burden, features, management and outcomes at local, national, regional and global level, thalassemia registries can allow the evaluation and bench marking of provided healthcare services, the detection of unmet clinical needs and the identification of inequalities in healthcare delivery. A total of 17 thalassemia registries has been in place since 1984, being characterized by heterogeneity and incomplete geographic coverage. Representativeness, interoperability, harmonization, quality assurance and sustainability are important features that thalassemia registries should pursue. The Thalassaemia International Federation (TIF) aims at promoting the coordination and collaboration in existing thalassemia registries and the establishment of new ones, with a particular focus on areas of emerging economies. In this regard, TIF has undertaken the design, development and implementation of a web-based platform to host a global thalassemia registry.

Coordinated β-globin expression and α2-globin reduction in a multiplex lentiviral gene therapy vector for β-thalassemia

A primary challenge in lentiviral gene therapy of β-hemoglobinopathies is to maintain low vector copy numbers to avoid genotoxicity while being reliably therapeutic for all genotypes. We designed a high-titer lentiviral vector, LVβ-shα2, that allows coordinated expression of the therapeutic β^A-T87Q-globin gene and of an intron-embedded miR-30-based short hairpin RNA (shRNA) selectively targeting the α2-globin mRNA. Our approach was guided by the knowledge that moderate reduction of α-globin chain synthesis ameliorates disease severity in β-thalassemia. We demonstrate that LVβ-shα2 reduces α2-globin mRNA expression in erythroid cells while keeping α1-globin mRNA levels unchanged and β^A-T87Q-globin gene expression identical to the parent vector. Compared with the first β^A-T87Q-globin lentiviral vector that has received conditional marketing authorization, BB305, LVβ-shα2 shows 1.7-fold greater potency to improve α/β ratios. It may thus result in greater therapeutic efficacy and reliability for the most severe types of β-thalassemia and provide an improved benefit/risk ratio regardless of the β-thalassemia genotype.

Prevalence and severity of Coronavirus disease 2019 (COVID-19) in Transfusion Dependent and Non-Transfusion Dependent β-thalassemia patients and effects of associated comorbidities: an Iranian nationwide study

BACKGROUND

Coronavirus disease 2019 (COVID-19) outbreak is a global and challenging disease that is accompany with mortality and morbidity.

AIM OF STUDY

We evaluated the prevalence and the impact of comorbidities in thalassemia Iranian patients affected by COVID-19.  Methods: A multicenter, retrospective, cross-sectional study was conducted across all comprehensive thalassemia centers in Iran, from January to June 15th, 2020.

RESULTS

Forty-three confirmed COVID-19 thalassemia patients (32 TDT, and 11 NTDT) were detected. The mean age of patients was 35.3 ± 11.5 years (range 9 - 67); 21 females and 22 males. Overall, 78.1% of TDT and 90.9% of NTDT patients were complicated with at least one comorbidity (P: 0.656). The overall mortality rate of thalassemia patients with COVID-19 was 18.6% while 27.3% was in NTDT patients compared to 15.6% in TDT patients (P:0.401). The dead group had a non-significant higher frequency of endocrinopathies compared to the recovered group (62.5% versus 45.7% P:0.457). Ten female thalassemia patients with positive COVID-19 had hypogonadism, six patients were receiving hormone replacement therapy and all of them recovered (zero death) compared to two deaths from 4 patients who were not receiving hormone replacement therapy (P:0.133). Furthermore, the prevalence of COVID-19 in NTDT patients was significantly higher than the general population (45 per 10,000 versus 22.29 per 10,000 respectively, P:0.018) while the prevalence of TDT was almost similar to the normal population (P:0.539). The mortality rate of COVID-19 was 4.71% in the normal Iranian population compared to 18.6% in β-thalassemias (P: <0.001) at the same date.

CONCLUSIONS

It is important to acknowledge that β-thalassemia patients, especially young adults/adults, have a chronic condition which may contribute to increase susceptibility to SARS-CoV-2 infection. A higher susceptibility to the infection was observed in patients with NTDT and in untreated hypogonadal female thalassemic patients. However, to confirm these data, more accurate designed studies are needed.

A comprehensive update of ICET-A Network on COVID-19 in thalassemias: what we know and where we stand

A review of the literature on COVID-19 pandemic in patients with thalassemias is presented. Globally, the prevalence of COVID-19 among  β-thalassemia patients seems to be lower than in general population; associated co-morbidities aggravated the severity of  COVID- 19, leading to a poorer prognosis, irrespective of age. A multicenter registry will enhance the understanding of COVID-19 in these patients and will lead to more evidence-based management recommendations.

[Epidemiological profile of hemoglobinopathies: a cross-sectional and descriptive index case study]

Hemoglobinopathies are congenital disorders resultimg from hemoglobin abnormalities. Major forms are often severe, their management is difficult and associated with a great psychosocial impact on patients and their families. They are classified as rare diseases and are still insufficiently known by health professionals. This lack of knowledge is at the origin of diagnostic errors, delay in their management and therefore high morbidity and mortality rate for these patients. In 2008, the World Health Organization (WHO) has published data on hemoglobinopathies epidemiology: more than 330.000 cases of hemoglobinopathy occur each year (83% of cases of sickle cell anemia, 17 % of cases of thalassemia). Hemoglobin disorders are responsible for approximately 3.4% of deaths among people under the age of 5. At the global level, approximately 7% of pregnant women would be carriers of a form of thalassemia and 1% of couples are at risk. However, they are relatively frequent in some regions of the globe where consanguineous marriages are common. We conducted a descriptive cross-sectional study based on two surveys, the first in May 2015 and the second in June of the same year. It was performed in the immunization days to deliver pneumococcal vaccine to the index cases and it was aimed to describe the epidemiological features of families at risk of hemoglobinopathies (index case study), whose index cases were treated in the Department of Pediatrics at the Provincial Hospital El Idrisi, Kenitra, Morocco. After having collected the epidemiological data from patients, laboratory tests were performed including: blood count with red blood cells morphological assessment using the MGG assay and automatic numbering of reticulocytes; hemoglobin electrophoresis at alkaline pH (8.8) and then at acid pH (5.4) on agarose gel and densitometric integration. 275 patients had laboratory profiles compatible with hemoglobinopathy. The majority of these patients were born to consanguineous marriages (83.1%) and came from the north regions of Morocco. This family survey allowed to identify families at risk with a high frequency of sickle cell anemia. Our results confirm the existence of hemoglobinopathies variants among Moroccan population.

The Molecular Spectrum of β- and α-Thalassemia Mutations in Non-Endemic Umbria, Central Italy

The aim of this study was to describe the mutational spectrum of hemoglobinopathies during the period 1988-2015 in Umbria, Central Italy, which has never been considered endemic for these conditions. Twenty-four different β-globin gene mutations were identified in 188 patients and eight different α-globin gene mutations in 74 patients. Sixty percent β-thalassemia (β-thal), 85.0% sickle cell disease, 44.0% Hb S (HBB: c.20A>T)/β-thal and 85.0% compound heterozygotes for hemoglobin (Hb) variant-carrying patients were diagnosed or molecularly characterized in the last 3 years. Moreover, most homozygous or compound heterozygous patients (84.5%) came from foreign countries, while only 15.5% were of Italian origin. These data are in accordance with the increasing foreign resident population in Umbria, which has nearly doubled in 10 years (2004-2014). Different from β-globin gene variations, no increasing trend in α defects was observed in our study cohort. Consistently, 58.0% of patients have an Italian origin, suggesting no broad influence of foreign migration in the α-globin genes genetic background. As few defects are prevalent in each country of origin or ethnic group, their knowledge may provide a proper strategy for the identification of mutations in immigrant individuals in a non-endemic region and be important for carrier identification and prenatal screening.

Gene Therapy for β-Hemoglobinopathies

β-Thalassemia and sickle cell disease (SCD) are the world's two most widely disseminated hereditary hemoglobinopathies. β-Thalassemia originated in the Mediterranean, Middle Eastern, and Asian regions, and SCD originated in central Africa. However, subsequent population migration means that these two diseases are now global and thus constitute a growing health problem in many countries. Despite remarkable improvements in medical care for patients with β-hemoglobinopathies, there is still only one definitive treatment option: allogeneic hematopoietic stem cell (HSC) transplantation. The development of gene therapy for β-hemoglobinopathies has been justified by (1) the limited availability of human leukocyte antigen (HLA)-identical donors, (2) the narrow window of application of HSC transplantation to the youngest patients, and (3) recent advances in HSC-based gene therapy. The huge ongoing efforts in translational medicine and the high number of related publications show that gene therapy has the potential to become the treatment of choice for patients who lack either an HLA genoidentical sibling or an alternative, medically acceptable donor. In this dynamic scientific context, we first summarize the main steps toward clinical translation of this therapeutic approach and then discuss novel lentiviral- and genome editing-based treatment strategies for β-hemoglobinopathies.

Spectrum of hemoglobin variants in the population of northern region of west bengal: an ethnogenetic proposition

Context:

The birth of transfusion-dependent states of hemoglobinopathies including thalassemias is preventable by population screening and genetic counseling. Magnitude is not addressed in the Northern Region of West Bengal where many ethnic variants inhabit.

Aims and Objectives:

The aim of the following study is to find out the burden of different entities of hemoglobinopathies, their correlation with ethnicity and the “at risk” groups.

Subjects and Methods:

A descriptive study was conducted from the Hematology Unit of North Bengal Medical College over 1 year on the subjects underwent screening for hemoglobinopathies for detection of abnormal hemoglobin (Hb) variants by “cation-exchange high-performance liquid chromatography” principle along with other relevant tests.

Statistical Analysis:

Data was analyzed by frequency distribution and Chi-square test assuming P value as 95% of the level of significance using the SPSS version 16 (SPSS Inc., Chicago, Illinois, U.S.A).

Result:

Abnormal Hb variant was 47.5% among 1872. Hb E trait (34.4%) was most common followed by Hb E disease (25.3%) and others. Hb E disorders (92.7%) were observed mostly among Rajbangsi population while E-β-thalassemias (40%) in the Muslims and a heterogeneous pattern noted among tribal and mongoloid.

Conclusion:

Hb E hemoglobinopathies was high among Rajbangsi and Muslims with identification of some other hemoglobinopathies involving tribal and mongoloid.

Thoracic cord compression by extramedullary hematopoiesis in thalassemia

Extramedullary hematopoiesis (EMH) refers to hematopoiesis occurring outside the medulla of bone. It may be physiologic or due to pathological conditions like hematopoietic disorders. EMH can involve liver, spleen, thorax, and lymph nodes. It can involve paraspinal tissues with extension and involvement of spinal canal. In our case, the diagnosis was confirmed by the history of the patient stating underlying hematological condition and by magnetic resonance imaging (MRI) findings showing large soft tissue masses in paraspinal areas with involvement of spinal canal and leading to cord compression.

Epidemiology of hemoglobinopathies and thalassemias in individuals referred to the haematology research centre, Shiraz University of Medical Sciences, Shiraz, Iran from 2006 to 2011

Hemoglobinopathies and thalassemias are the most frequent genetic hereditary disorders with an increasing global health burden, especially in low- and middle-income countries. We aimed to determine the epidemiologic pattern of hemoglobinopathies and thalassemias in individuals referred to the Haematology Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran, which is the most important referral center in Southern Iran during 2006 to 2011. The most frequent abnormality was β-thalassemia (β-thal) minor (24.0%), followed by α-thalassemia (α-thal) trait (10.0%), hemoglobin (Hb) S trait (4.0%) and Hb D-Punjab trait (4.0%). Because this center is a referral center, we detected a higher prevalence compared to the normal population; however, these data could help policymakers and health service providers to better programming for prevention of births affected with Hb disorders.

Circulating nucleic acids in plasma and serum: applications in diagnostic techniques for noninvasive prenatal diagnosis

The analysis of fetal nucleic acids in maternal blood 13 years ago has led to the initiation of noninvasive methods for the early determination of fetal gender, rhesus D status, and a number of aneuploid disorders and hemoglobinopathies. Subsequently, a comparatively large quantity of fetal DNA and RNA has been demonstrated in amniotic fluid as well as small amounts in premature infant saliva. The DNA and RNA in amniotic fluid has permitted an analysis of core transcriptomes, whilst the DNA and RNA in saliva allows the early detection and treatment monitoring of fetal developmental problems. These aspects are discussed together with the methodology and limits of analysis for noninvasive prenatal diagnosis in predictive, preventive, and personalized medicine.

Inherited hemoglobin disorders in an Afro-Amazonian community: Saracura

The most common hemoglobinopathies, viz, hemoglobins S and C, and α- and β-thalassemias, were investigated through the molecular screening of 116 subjects from the community of Saracura, comprising fugitive African slaves from farms of the municipality of Santarém, in the west of Pará State, Brazilian Amazon. The observed frequency of the HBB*S gene (0.9%) was significantly lower than that encountered in other Afro-derived communities in the region. Concomitantly, the absence of the HBB*C allele has been reported for most of the Afro-Amazonian communities thus far studied. As remnant populations of quilombos are generally small, the heterogeneous distribution of HBB*S and HBB*C alleles among them is probably due to genetic drift and/or founder effect. The observed frequency of 3.7 kb deletion in Saracura (8.5%) was consistent with the African origin of the population, with a certain degree of local differentiation and admixture with individuals of Caucasian ancestry, placed in evidence by the occurrence of - -(MED) deletion (1.2%), a common mutation in Mediterranean regions. As regards β-thalassemia, among the seven different mutations found in Saracura, three β^o and two β⁺ mutations were of Mediterranean origin, and two β⁺ of African. Thus, only 28% of the local β-thalassemia mutations found in Saracura were of African origin.

Peroxiredoxin-2 expression is increased in beta-thalassemic mouse red cells but is displaced from the membrane as a marker of oxidative stress

Peroxiredoxin 2 (Prx2), the third most abundant cytoplasmic protein in red blood cells (RBCs), is involved in the defense against oxidative stress. Although much is known about Prx2 in healthy RBCs, its role in pathological RBCs remains largely unexplored. Here, we show that the expression and net content of Prx2 are markedly increased in RBCs from two mouse models of beta-thalassemia (beta-thal; Hbb(th/th) and Hbb(th3/+) strains). We also demonstrate that the increased expression of Prx2 correlates with the severity of the disease and that the amount of Prx2 bound to the membrane is markedly reduced in beta-thal mouse RBCs. To explore the impact of oxidative stress on Prx2 membrane association, we examined Prx2 dimerization and membrane translocation in murine RBCs exposed to various oxidants (phenylhydrazine, PHZ; diamide; H(2)O(2)). PHZ-treated RBCs, which mimic the membrane damage in beta-thal RBCs, exhibited a kinetic correlation among Prx2 membrane displacement, intracellular methemoglobin levels, and hemichrome membrane association, suggesting the possible masking of Prx2 docking sites by membrane-bound hemichromes, providing a possible mechanism for the accumulation of oxidized/dimerized Prx2 in the cytoplasm and the increased membrane damage in beta-thal RBCs. Thus, reduced access of Prx2 to the membrane in beta-thal RBCs represents a new factor that could contribute to the oxidative damage characterizing the pathology.