RESUMO
I was attracted to hematology because by combining clinical findings with the use of a microscope and simple laboratory tests, one could often make a diagnosis. I was attracted to genetics when I learned about inherited blood disorders, at a time when we had only hints that somatic mutations were also important. It seemed clear that if we understood not only what genetic changes caused what diseases but also the mechanisms through which those genetic changes contribute to cause disease, we could improve management. Thus, I investigated many aspects of the glucose-6-phosphate dehydrogenase system, including cloning of the gene, and in the study of paroxysmal nocturnal hemoglobinuria (PNH), I found that it is a clonal disorder; subsequently, we were able to explain how a nonmalignant clone can expand, and I was involved in the first trial of PNH treatment by complement inhibition. I was fortunate to do clinical and research hematology in five countries; in all of them, I learned from mentors, from colleagues, and from patients.
Assuntos
Hemoglobinúria Paroxística , Humanos , Hemoglobinúria Paroxística/genética , Hemoglobinúria Paroxística/patologia , Células Sanguíneas/patologia , Células Clonais/patologiaRESUMO
Sickle cell disease (SCD) is a common genetic blood disorder associated with acute and chronic pain, progressive multiorgan damage, and early mortality. Recent advances in technologies to manipulate the human genome, a century of research and the development of techniques enabling the isolation, efficient genetic modification, and reimplantation of autologous patient hematopoietic stem cells (HSCs), mean that curing most patients with SCD could soon be a reality in wealthy countries. In parallel, ongoing research is pursuing more facile treatments, such as in-vivo-delivered genetic therapies and new drugs that can eventually be administered in low- and middle-income countries where most SCD patients reside.
Assuntos
Anemia Falciforme , Transplante de Células-Tronco Hematopoéticas , Humanos , Anemia Falciforme/genética , Anemia Falciforme/terapia , Edição de Genes/métodos , Células-Tronco Hematopoéticas , Terapia GenéticaRESUMO
Fetal hemoglobin (HbF) reactivation expression through CRISPR-Cas9 is a promising strategy for the treatment of sickle cell disease (SCD). Here, we describe a genome editing strategy leading to reactivation of HbF expression by targeting the binding sites (BSs) for the lymphoma-related factor (LRF) repressor in the γ-globin promoters. CRISPR-Cas9 treatment in healthy donor (HD) and patient-derived HSPCs resulted in a high frequency of LRF BS disruption and potent HbF synthesis in their erythroid progeny. LRF BS disruption did not impair HSPC engraftment and differentiation but was more efficient in SCD than in HD cells. However, SCD HSPCs showed a reduced engraftment and a myeloid bias compared with HD cells. We detected off-target activity and chromosomal rearrangements, particularly in SCD samples (likely because of the higher overall editing efficiency) but did not impact the target gene expression and HSPC engraftment and differentiation. Transcriptomic analyses showed that the editing procedure results in the up-regulation of genes involved in DNA damage and inflammatory responses, which was more evident in SCD HSPCs. This study provides evidence of efficacy and safety for an editing strategy based on HbF reactivation and highlights the need of performing safety studies in clinically relevant conditions, i.e., in patient-derived HSPCs.
RESUMO
Thalassemias are a group of inherited monogenic disorders characterized by defects in the synthesis of one or more of the globin chain subunits of the hemoglobin tetramer. Delta-beta (δß-) thalassemia has large deletions in the ß globin gene cluster involving δ- and ß-globin genes, leading to absent or reduced synthesis of both δ- and ß-globin chains. Here, we used direct globin-chain analysis using tandem mass spectrometry for the diagnosis of δß-thalassemia. Two cases from unrelated families were recruited for the study based on clinical and hematological evaluation. Peptides obtained after trypsin digestion of proteins extracted from red blood cell pellets from two affected individuals and their parents were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Mass spectrometric analysis revealed a severe reduction in δ, ß, and Aγ globin proteins with increased Gγ globin protein in the affected individuals. The diagnosis of Gγ(Aγδß)0 -thalassemia in the homozygous state in the affected individuals and in the heterozygous state in the parents was made from our results. The diagnosis was confirmed at the genetic level using multiplex ligation-dependent probe amplification (MLPA). Our findings demonstrate the utility of direct globin protein quantitation using LC-MS/MS to quantify individual globin proteins reflecting changes in globin production. This approach can be utilized for accurate and timely diagnosis of hemoglobinopathies, including rare variants, where existing diagnostic methods provide inconclusive results.
Assuntos
Espectrometria de Massas em Tandem , Humanos , Espectrometria de Massas em Tandem/métodos , Masculino , Feminino , Cromatografia Líquida/métodos , Globinas beta/genética , gama-Globinas/genéticaRESUMO
BACKGROUND: Red blood cell (RBC) transfusion remains a major treatment for sickle cell disease (SCD). Patients with SCD have a high prevalence of renal impairment and cardiorespiratory disease, conferring risk of transfusion-associated circulatory overload (TACO). STUDY DESIGN AND METHODS: We describe an approach, titled euvolemic automated transfusion (EAT), to transfuse SCD patients with severe anemia who are at risk of TACO. In EAT, plasmapheresis is performed using donor RBCs, rather than albumin or plasma, as replacement fluid. Euvolemia is maintained. A retrospective analysis was conducted of patients with SCD who underwent EAT at our institution over a 10-year period, to evaluate the efficacy and safety of EAT. RESULTS: Eleven SCD patients underwent 109 EAT procedures (1-59 procedures per patient). The median age was 42 years (IQR = [30-49]) and 82% (n = 9) were female. Most (82%; n = 9) patients had severe chronic kidney disease and 55% (n = 6) had heart failure. One (9%) patient had a history of life-threatening TACO. Mean pre- and post-procedure Hct values were 19.8% (SD ± 1.6%) and 29.1% (SD ± 1.4%), respectively. The average Hct increment was 3.2% per RBC unit. Only two EAT-related complications were recorded during the 109 procedures: central line-associated infection and citrate toxicity (muscle cramping). EAT used an average of two RBC units less than that projected for standard automated RBC exchange. CONCLUSION: Our findings suggest that EAT is safe and effective to treat patients with SCD and severe anemia, who are at risk for TACO. EAT requires fewer RBC units compared to automated RBC exchange.
Assuntos
Anemia Falciforme , Reação Transfusional , Humanos , Feminino , Adulto , Masculino , Estudos Retrospectivos , Anemia Falciforme/complicações , Anemia Falciforme/terapia , Transfusão de Sangue , Transfusão de Eritrócitos/efeitos adversos , Transfusão de Eritrócitos/métodos , Eritrócitos , Reação Transfusional/etiologiaRESUMO
BACKGROUND: The data to support chronic automated red cell exchange (RCE) in sickle cell disease (SCD) outside of stroke prevention, is limited, especially in adults. STUDY DESIGN AND METHODS: A retrospective analysis was conducted of patients with SCD who were referred for chronic RCE at our institution over a 10-year period. Data that were evaluated included patient demographics, referral indications, and procedural details (e.g., vascular access, adverse events, etc.). In a subanalysis, the number of annual acute care encounters during 3 years of chronic RCE was compared with that in the year preceding the first RCE. RESULTS: A total of 164 patients were referred for chronic RCE: median age was 28 years (interquartile range [IQR] = 22-36) at referral and 60% were female. Seventy (42.6%) were naïve to chronic transfusion (simple or RCE) prior to referral. The leading indications for referral were refractory pain (73/164, 44.5%) and iron overload (57/164, 34.7%). A total of 5090 procedures occurred during the study period (median = 19, IQR = 5-45). Of the 138 patients who had central vascular access, 8 (6%) and 16 (12%) had ≥1 central-line-related thrombosis and/or infection, respectively. Of those who were not RBC alloimmunized at initiation of RCE, 12/105 (11.4%) developed new antibodies during chronic RCE. In those 30 patients who were adherent to therapy for 3 years, there was no significant difference in acute care encounters following initiation of RCE. CONCLUSION: Prospective clinical trials are needed to determine which patients are most likely to benefit from chronic RCE and refine selection accordingly.
Assuntos
Anemia Falciforme , Transfusão de Eritrócitos , Humanos , Anemia Falciforme/terapia , Feminino , Masculino , Estudos Retrospectivos , Adulto , Adulto JovemRESUMO
REHem-AR was created in 2013. The progressive implementation of neonatal screening for haemoglobinopathies in Spanish autonomous communities where the registry had not been implemented, as well as the addition of new centres during this period, has considerably increased the sample of patients covered. In this study, we update our previous publication in this area, after a follow-up of more than 5 years. An observational, descriptive, multicentre and ambispective study of adult and paediatric patients with haemoglobinopathies and rare anaemias registered in REHem was performed. The data are from a cross-sectional analysis performed on 1 June, 2023. The study population comprised 1,756 patients, of whom 1,317 had SCD, 214 had thalassaemia and 224 were diagnosed with another condition. Slightly more than one third of SCD patients (37%) were diagnosed based on neonatal bloodspot screening, and the mean age at diagnosis was 2.5 years; 71% of thalassaemia patients were diagnosed based on the presence of anaemia. Vaso-occlusive crisis and acute chest syndrome continue to be the most frequent complications in SCD. HSCT was performed in 83 patients with SCD and in 50 patients with thalassaemia. Since the previous publication, REHem-AR has grown in size by more than 500 cases. SCD and TM are less frequent in Spain than in other European countries, although the data show that rare anaemias are frequent within rare diseases. REHem-AR constitutes an important structure for following the natural history of rare anaemias and enables us to calculate investment needs for current and future treatments.
Assuntos
Hemoglobinopatias , Sistema de Registros , Humanos , Espanha/epidemiologia , Masculino , Feminino , Criança , Hemoglobinopatias/epidemiologia , Hemoglobinopatias/diagnóstico , Pré-Escolar , Adulto , Recém-Nascido , Estudos Transversais , Adolescente , Lactente , Doenças Raras/epidemiologia , Triagem Neonatal , Pessoa de Meia-Idade , Adulto Jovem , Seguimentos , Talassemia/epidemiologia , Talassemia/terapiaRESUMO
INTRODUCTION: The increase in the number of patients with hemoglobinopathies in Europe in recent decades highlights the need for more detailed epidemiological information in Spain. To fulfil this need, the Spanish Society of Pediatric Hematology and Oncology (SEHOP) sponsored the creation of a national registry of hemoglobinopathies known as REHem-AR (Spanish Registry of Hemoglobinopathies and Rare Anemias). Data from the transfusion-dependent (TDT) and non-transfusion-dependent (NTDT) ß-thalassemia cohorts are described and analyzed. METHODS: We performed an observational, multicenter, and ambispective study, which included patients of any age with TDT and NTDT, registered up to December 31, 2021. RESULTS: Among the 1741 patients included, 168 cases of thalassemia were identified (103 TDT and 65 NTDT-patients). Survival at 18 years was 93% for TDT and 100% for NTDT. Regarding management, 80 patients with TDT (77.7%) and 23 patients with NTDT (35.4%) started chelation treatment during follow-up, with deferasirox being the most widely used. A total of 76 patients within the TDT cohort presented at least 1 complication (73.8%), the most frequent being hemosiderosis and osteopenia-osteoporosis. Comparison of both cohorts revealed significant differences in the diagnosis of hepatic hemosiderosis (p = 0.00024), although these were not observed in the case of cardiac iron overload (p = 0.27). DISCUSSION: Our registry enabled us to describe the management of ß thalassemia in Spain and to analyze the morbidity and mortality of the cohorts of patients with TDT and NTDT. Complications related to iron overload in TDT and NTDT account for most of the morbidity and mortality of the disease, which is associated with a considerable social, psychological, and economic impact, although cardiac, osteopathy and endocrinological complications requiring more attention. The convenience and simplicity of online registries make it possible to homogenize variables and periodically update data, thus providing valuable information on these diseases.
Assuntos
Hemossiderose , Sobrecarga de Ferro , Talassemia beta , Humanos , Talassemia beta/complicações , Talassemia beta/epidemiologia , Talassemia beta/terapia , Transfusão de Sangue , Demografia , Sobrecarga de Ferro/etiologiaRESUMO
BACKGROUND: Hematopoietic cell transplantation (HCT) is an established curative therapy for transfusion-dependent thalassemia (TDT) and sickle cell disease (SCD). The latest American Society of Hematology guidelines recommend myeloablative preparative regimen in patients under 18 years of age. PROCEDURE: The objective was to demonstrate safety and efficacy of a reduced intensity conditioning (RIC) regimen including high-dose fludarabine, anti-thymocyte globulin, and targeted busulfan as a single alkylator to sub-myeloablative exposures. RESULTS: Between 2012 and 2021, 11 patients with SCD and five patients with TDT and matched related donor (MRD) HCT were included. The median age at transplantation was 8.3 years (range: 3.7-18.8 years). The median administered busulfan AUC was 67.4 mg/L×h (range: 60.7-80 mg/L×h). Overall survival was 93.8% and event-free survival 87.5% with one engrafted SCD patient with pre-existing moyamoya disease succumbing after drainage of a subdural hematoma. One SCD patient developed a secondary graft failure and was treated with a second HCT. Myeloid chimerism was full in all other patients with a median follow-up time of 4.1 years (range: 2.0-11.1 years), whereas T-cell donor chimerism was frequently mixed. CONCLUSION: This RIC conditioning followed by MRD HCT is sufficiently myeloablative to cure pediatric patients with hemoglobinopathies without the need for additional total body irradiation or thiotepa.
Assuntos
Bussulfano , Transplante de Células-Tronco Hematopoéticas , Hemoglobinopatias , Condicionamento Pré-Transplante , Humanos , Bussulfano/administração & dosagem , Bussulfano/uso terapêutico , Condicionamento Pré-Transplante/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Pré-Escolar , Criança , Masculino , Feminino , Adolescente , Hemoglobinopatias/terapia , Seguimentos , Taxa de Sobrevida , Doença Enxerto-Hospedeiro/etiologia , Sobrevivência de Enxerto , Vidarabina/análogos & derivados , Vidarabina/administração & dosagem , Vidarabina/uso terapêutico , Anemia Falciforme/terapia , Doadores de Tecidos , Prognóstico , Talassemia/terapiaRESUMO
Drepanocytosis is a genetic disease relevant for its epidemiological, clinical and socio-economic aspects. In our country the prevalence is highly uneven with peaks in former malaria areas, but migration flows in recent years have led to significant changes. In this document we review the screening programs currently existing in Italy with particular emphasis on newborn screening, which in other countries around the world, including within Europe, is at most universal and mandatory. The essential laboratory issues are reviewed, from sampling aspects (cord blood or peripheral), to the analytical (analytical methods dedicated to neonatal screening and adult carrier detection) and post analytical (reporting, informative) ones. An economic analysis based on data collected in the province of Modena is also proposed, clearly showing that neonatal screening is also beneficial from an economic point of view.
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Anemia Falciforme , Triagem Neonatal , Humanos , Anemia Falciforme/diagnóstico , Anemia Falciforme/epidemiologia , Anemia Falciforme/sangue , Recém-Nascido , Triagem Neonatal/métodos , Itália/epidemiologiaRESUMO
OBJECTIVES: Accurate quantification of hemoglobin (Hb) A2 is vital for diagnosing ß-thalassemia carriers. This study aimed to assess the precision and diagnostic utility of HbA2 measurements using the new high-performance liquid chromatography (HPLC) method, Premier Resolution, in comparison to capillary electrophoresis (CE). METHODS: We analyzed 418 samples, previously identified as A2A by CE, using Premier Resolution-HPLC. We compared the results, established correlations, and determined an optimal HbA2 cutoff value for ß-thalassemia screening. Additionally, we prospectively evaluated the chosen cutoff value in 632 samples. Mutations in the ß- and α-globin genes were identified using polymerase chain reaction (PCR) techniques and DNA sequencing. RESULTS: HbA2 levels were consistently higher with Premier Resolution, yet there was a significant correlation with CE in all samples (bias, -0.33; r, 0.991), ß-thalassemia (bias, -0.27; r, 0.927), and non-ß-thalassemia carriers (bias, -0.36; r, 0.928). An HbA2 cutoff value of ≥4.0â¯% for ß-thalassemia screening achieved 100â¯% sensitivity and 99.6â¯% specificity. Further validation yielded sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 97.3â¯, 99.8, 97.3, 99.8, and 99.7â¯%, respectively. We also identified a rare ß-Hb variant, Hb La Desirade [HBB:c.389C>T], associated with ß-thalassemia and co-inherited with a single α-globin gene. CONCLUSIONS: The Premier Resolution HPLC is a reliable and accurate method for routine ß-thalassemia carrier screening, aligning with existing CE methods.
Assuntos
Hemoglobina Falciforme , Talassemia beta , Humanos , Talassemia beta/diagnóstico , Talassemia beta/genética , Hemoglobina A/análise , Reprodutibilidade dos Testes , Hemoglobina A2/genética , Hemoglobina A2/análise , Mutação , alfa-Globinas/genéticaRESUMO
PURPOSE: Opioids are widely used to treat painful vaso-occlusive crises (VOC) in sickle cell disease (SCD). However, due to opioids' significant adverse effect profiles, the search for alternative therapies continues from the past to the present. The study aimed to investigate the efficacy of acetaminophen and dexketoprofen in the treatment of painful VOC. METHODS: This study is a single-center, prospective, non-randomized, single-blinded, controlled study. The study comprised two groups: the first administered acetaminophen and dexketoprofen mixed group, while the second received them sequential group. Opioids were used in patients with persistent pain despite these analgesics. Demographic and laboratory information, pain scores, opioid requirement, dose amount, side effects, and length of hospital stay of the patients were recorded. RESULTS: The study comprised 56 (100%) patients with painful VOC, 29 (51.8%) from the mixed group, and 27 (48.2%) from the sequential group. Opioid use was seen in 16 (55.2%) patients in the mixed group and 21 (77.8%) patients in the sequential group (p = 0.074). The median amount of opioid used was significantly lower in the mixed group than in the sequential group (p < 0.001). Also, the median length of hospital stay was significantly lower in the mixed group than in the sequential group (p < 0.001). CONCLUSION: Our study suggests that administering acetaminophen and dexketoprofen in the mix for the treatment of painful VOC in patients with SCD may be a more efficient approach compared to sequential administration. This approach appears to reduce opioid usage and shorten hospital stays.
Assuntos
Anemia Falciforme , Cetoprofeno/análogos & derivados , Trometamina , Compostos Orgânicos Voláteis , Humanos , Acetaminofen/uso terapêutico , Analgésicos Opioides/uso terapêutico , Estudos Prospectivos , Compostos Orgânicos Voláteis/uso terapêutico , Dor/tratamento farmacológico , Anemia Falciforme/tratamento farmacológicoRESUMO
BACKGROUND: Immunohematology tests are crucial in transfusion safety. This study aimed to assess irregular red blood cell (RBC) antibodies, abnormal hemoglobin and dangerous universal blood donors at a public blood center in a Brazilian metropolitan area. METHODS: A cross-sectional study included all consecutive blood donors from January 2018 to December 2021 at the Brasília Blood Center Foundation, Federal District (FD), Brazil. RESULTS: Among 205,965 blood donations, irregular RBC antibodies were found in 743 (0.4 %). Abnormal hemoglobin was observed in 5396 (2.6 %): 3959 (1.9 %) with Hb AS, 1344 (0.7 %) with Hb AC, and 93 (< 0,1 %) with other hemoglobin variants. Of O group donors, 12.5 % (9646) had hemolysins: 12.5 % (2410) both anti-A and anti-B, 8.7 % (9646) only anti-A, and 1.6 % (1763) only anti-B hemolysins. Female sex (p < 0.001) and increasing age (p < 0.001) were associated with irregular RBC antibodies. O and/or Rh(D)-positive blood groups had a lower prevalence of irregular RBC antibodies compared to other ABO and/or Rh(D)-negative groups. Age (p < 0.001) and female sex (p < 0.001) were associated with anti-A/anti-B hemolysins, while FD residency was associated with reduced incidence (p < 0.001). CONCLUSION: Anti-A/anti-B hemolysins in O group donors, abnormal hemoglobin and irregular RBC antibodies pose risks to transfusion practice and should not be overlooked. Advancing age, female sex, ABO blood group other than O, or Rh(D)- negative are independently associated with the presence of irregular RBC antibodies. Dangerous universal blood donors were associated with advanced age, female gender, Rh(D)-positive blood type, and individuals residing in a Brazilian state other than where the blood center was located.
Assuntos
Doadores de Sangue , Eritrócitos , Humanos , Brasil , Feminino , Masculino , Estudos Transversais , Adulto , Pessoa de Meia-Idade , Eritrócitos/imunologia , Hemoglobinas/análise , Adolescente , Adulto Jovem , Bancos de SangueRESUMO
Thalassemia major is one of the health problems in Iraq, especially in Kurdistan. Pre-marriage mandatory preventive screening program was established in Kurdistan in 2008, which allowed us to study the prevalence of different hemoglobinopathies among newly married young adults in this region. A total of 1154 subjects (577 couples) attending the Koya district, premarital Health center, were screened using red cell indices. Those who had mean corpuscular volume (MCV)<80 fl and mean corpuscular hemoglobin (MCH)<27 pg had high-performance liquid chromatography and iron studies. Out of 1154 individuals that were evaluated, 183 (11.9%) had low MCV and MCH. Of the former 183 subjects, 69 (5.97%) had ß-thalassemia trait, 10 (0.86%) had δß-thalassemia trait, and no other hemoglobinopathies were recorded in our study. There was second-degree consanguinity in 4.7% of all 577 couples. In two couples, both partners had ß-thalassemia trait and both were consanguineous. Both couples decided to separate after counseling. Based on the current study, the role of the premarital screening program in decreasing the number of new thalassemia major cases among the Kurdish population is laudable. Therefore, mandatory premarital screening is advised in all parts of Iraq.
Assuntos
Hemoglobinopatias , Talassemia beta , Adulto Jovem , Humanos , Talassemia beta/diagnóstico , Talassemia beta/epidemiologia , Talassemia beta/genética , Iraque/epidemiologia , Hemoglobinopatias/diagnóstico , Hemoglobinopatias/epidemiologia , Hemoglobinopatias/genética , Índices de Eritrócitos , Programas de Rastreamento , Exames Pré-NupciaisRESUMO
Unstable hemoglobin (Hb) variants are a rare cause of congenital hemolytic anemia. We describe a Chinese girl who presented with transfusion-dependent anemia in early infancy. Her diagnosis of Hb Calgary [ß64(E8)Gly > Val; HBB:c.194G > T] was not made until molecular testing was performed at the age of 5 years. Our case highlights the importance of early genetic testing in order to make the diagnosis, which may not only be useful for patient management and family counseling, but also for avoiding further unnecessary investigative attempts.
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Hemoglobinas Anormais , Pré-Escolar , Feminino , Humanos , Anemia Hemolítica Congênita/genética , Anemia Hemolítica Congênita/diagnóstico , Anemia Hemolítica Congênita/complicações , Testes Genéticos , Hemoglobinas Anormais/genética , MutaçãoRESUMO
Hemoglobinopathies are monogenic disorders affecting hemoglobin synthesis. Thalassemia and sickle cell disease (SCD) are considered the two major hemoglobinopathies. Thalassemia is a genetic disorder and one of the major hemoglobinopathies determined by an impairment of globin chain production, which causes an alteration of erythropoiesis, an improvement in hemolysis, and an alteration of iron homoeostasis. In SCD, the mutations are on the ß-globin chain of hemoglobin which results in a substitution of glutamic acid by valine with consequent formation of Hemoglobin S (HbS). Several factors are involved in bone metabolism alteration in patients with hemoglobinopathies, among them hormonal deficiency, bone marrow hyperplasia, iron overload, inflammation, and increased bone turnover. Bone metabolism is the result of balance maintenance between bone deposition and bone resorption, by osteoblasts (OBs) and osteoclasts (OCs). An impairment of this balance is responsible for the onset of bone diseases, such as osteoporosis (OP). Therefore, here we will discuss the alteration of bone metabolism in patients with hemoglobinopathies and the possible therapeutic strategies to contain and/or counteract bone health impairment in these patients, taking into consideration not only the pharmacological treatments already used in the clinical armamentarium, but also the new possible therapeutic strategies.
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Anemia Falciforme , Hemoglobinopatias , Talassemia , Talassemia beta , Humanos , Densidade Óssea , Hemoglobinopatias/genética , Anemia Falciforme/genética , Hemoglobina Falciforme , Talassemia beta/genéticaRESUMO
The heme-regulated inhibitor (HRI) is a heme-sensing kinase that regulates mRNA translation in erythroid cells. In heme deficiency, HRI is activated to phosphorylate eukaryotic initiation factor 2α and halt production of globins, thus avoiding accumulation of heme-free globin chains. HRI is inhibited by heme via binding to one or two heme-binding domains within the HRI N-terminal and kinase domains. HRI has recently been found to inhibit fetal hemoglobin (HbF) production in adult erythroid cells. Depletion of HRI increases HbF production, presenting a therapeutically exploitable target for the treatment of patients with sickle cell disease or thalassemia, which benefit from elevated HbF levels. HRI is known to be an oligomeric enzyme that is activated through autophosphorylation, although the exact nature of the HRI oligomer, its relation to autophosphorylation, and its mode of heme regulation remain unclear. Here, we employ biochemical and biophysical studies to demonstrate that HRI forms a dimeric species that is not dependent on autophosphorylation, the C-terminal coiled-coil domain in HRI is essential for dimer formation, and dimer formation facilitates efficient autophosphorylation and activation of HRI. We also employ kinetic studies to demonstrate that the primary avenue by which heme inhibits HRI is through the heme-binding site within the kinase domain, and that this inhibition is relatively independent of binding of ATP and eukaryotic initiation factor 2α substrates. Together, these studies highlight the mode of heme inhibition and the importance of dimerization in human HRI heme-sensing activity.
Assuntos
Heme , eIF-2 Quinase , Humanos , Dimerização , eIF-2 Quinase/genética , eIF-2 Quinase/metabolismo , Fator de Iniciação 2 em Eucariotos/metabolismo , Heme/metabolismo , Cinética , Fosforilação , Ligação ProteicaRESUMO
BACKGROUND: The correlation between thalassemia and malignancies other than hepatocellular carcinoma (HCC) and the possible relationship between other hemoglobinopathies and tumor risk have been poorly evaluated. METHODS: Eight Italian specialized centers evaluated the incidence of malignant neoplasms in hemoglobinopathies as well as their sites and features. The study cohort included 4631 patients followed between 1970 and 2021 (transfusion-dependent ß-thalassemia, 55.6%; non-transfusion-dependent thalassemia, 17.7%; sickle cell disease, 17.6%; hemoglobin H disease, 8.3%). RESULTS: A total of 197 diagnoses of cancer were reported (incidence rate, 442 cases per 100,000 person-years). The liver was the most frequent site of tumors in both sexes, with a higher incidence (190 cases per 100,000 person-years) in comparison with the general population found in all types of hemoglobinopathies (except hemoglobin H disease). In recent years, tumors have become the second cause of death in patients with transfusion-dependent thalassemia. A lower risk of breast and prostate cancer was observed in the whole group of patients with hemoglobinopathies. The first cancer diagnoses dated back to the 1980s, and the incidence rate sharply increased after the 2000s. However, although the incidence rate of cancers of all sites but the liver continued to show an increasing trend, the incidence of HCC showed stability. CONCLUSIONS: These findings provide novel insights into the relationship between cancer and hemoglobinopathies and suggest that the overall risk is not increased in these patients. HCC has been confirmed as the most frequent tumor, but advances in chelation and the drugs that have led to the eradication of hepatitis C may explain the recent steadiness in the number of diagnoses that is reported here.
Assuntos
Carcinoma Hepatocelular , Hemoglobinopatias , Neoplasias Hepáticas , Talassemia alfa , Masculino , Feminino , Humanos , Incidência , Talassemia alfa/diagnóstico , Talassemia alfa/epidemiologia , Carcinoma Hepatocelular/epidemiologia , Neoplasias Hepáticas/epidemiologia , Hemoglobinopatias/epidemiologia , Hemoglobinopatias/diagnósticoRESUMO
Brazilian quilombos are communities formed by enslaved Africans and their descendants all over the country during slavery and shortly after its abolition. Quilombos harbor a great fraction of the largely unknown genetic diversity of the African diaspora in Brazil. Thus, genetic studies in quilombos have the potential to provide important insights not only into the African roots of the Brazilian population but also into the genetic bases of complex traits and human adaptation to diverse environments. This review summarizes the main results of genetic studies performed on quilombos so far. Here, we analyzed the patterns of African, Amerindian, European, and subcontinental ancestry (within Africa) of quilombos from the five different geographic regions of Brazil. In addition, uniparental markers (from the mtDNA and the Y chromosome) studies are analyzed together to reveal demographic processes and sex-biased admixture that occurred during the formation of these unique populations. Lastly, the prevalence of known malaria-adaptive African mutations and other African-specific variants discovered in quilombos, as well as the genetic bases of health-related traits, are discussed here, together with their implication for the health of populations of African descent.
Assuntos
Aclimatação , População Africana , Nível de Saúde , Humanos , População Africana/genética , Brasil , DNA Mitocondrial , MitocôndriasRESUMO
In this issue, Hokland et al. offer an interesting view of the different approaches on how to treat a beta-thalassemia patient. The principal concerns, that this report reveals, are the very wide differences in the facilities and economic resources available for the care of patients. Management of thalassemia should become a word wide health care priority and may include at last those two steps: national and international registries; national programs for screening couples at risk and providing preventive measures to prevent births of patients with thalassemia. Commentary on: Hokland et al. Thalassaemia-A global view. Br J Haematol. 2023;201:208-223.