Correcting ß-thalassemia by combined therapies that restrict iron and modulate erythropoietin activity.

ß-Thalassemia intermedia is a disorder characterized by ineffective erythropoiesis (IE), anemia, splenomegaly, and systemic iron overload. Novel approaches are being explored based on the modulation of pathways that reduce iron absorption (ie, using hepcidin activators like Tmprss6-antisense oligonucleotides [ASOs]) or increase erythropoiesis (by erythropoietin [EPO] administration or modulating the ability of transferrin receptor 2 [Tfr2] to control red blood cell [RBC] synthesis). Targeting Tmprss6 messenger RNA by Tmprss6-ASO was proven to be effective in improving IE and splenomegaly by inducing iron restriction. However, we postulated that combinatorial strategies might be superior to single therapies. Here, we combined Tmprss6-ASO with EPO administration or removal of a single Tfr2 allele in the bone marrow of animals affected by ß-thalassemia intermedia (Hbbth3/+). EPO administration alone or removal of a single Tfr2 allele increased hemoglobin levels and RBCs. However, EPO or Tfr2 single-allele deletion alone, respectively, exacerbated or did not improve splenomegaly in ß-thalassemic mice. To overcome this issue, we postulated that some level of iron restriction (by targeting Tmprss6) would improve splenomegaly while preserving the beneficial effects on RBC production mediated by EPO or Tfr2 deletion. While administration of Tmprss6-ASO alone improved the anemia, the combination of Tmprss6-ASO + EPO or Tmprss6-ASO + Tfr2 single-allele deletion produced significantly higher hemoglobin levels and reduced splenomegaly. In conclusion, our results clearly indicate that these combinatorial approaches are superior to single treatments in ameliorating IE and anemia in ß-thalassemia and could provide guidance to translate some of these approaches into viable therapies.

The HRI-regulated transcription factor ATF4 activates BCL11A transcription to silence fetal hemoglobin expression.

Reactivation of fetal hemoglobin remains a critical goal in the treatment of patients with sickle cell disease and ß-thalassemia. Previously, we discovered that silencing of the fetal γ-globin gene requires the erythroid-specific eIF2α kinase heme-regulated inhibitor (HRI), suggesting that HRI might present a pharmacologic target for raising fetal hemoglobin levels. Here, via a CRISPR-Cas9-guided loss-of-function screen in human erythroblasts, we identify transcription factor ATF4, a known HRI-regulated protein, as a novel γ-globin regulator. ATF4 directly stimulates transcription of BCL11A, a repressor of γ-globin transcription, by binding to its enhancer and fostering enhancer-promoter contacts. Notably, HRI-deficient mice display normal Bcl11a levels, suggesting species-selective regulation, which we explain here by demonstrating that the analogous ATF4 motif at the murine Bcl11a enhancer is largely dispensable. Our studies uncover a linear signaling pathway from HRI to ATF4 to BCL11A to γ-globin and illustrate potential limits of murine models of globin gene regulation.

Foxo3 gene expression and oxidative status in beta-thalassemia minor subjects

ABSTRACT Background: Oxidative stress may aggravate symptoms of hemolytic anemias such as beta-thalassemia. FoxO3 activation results in resistance to oxidative stress in fibroblasts and neuronal cell cultures. Objective: The purpose of this research was to study FoxO3 gene expression and oxidative status in beta-thalassemia minor individuals. Methods: Sixty-three subjects (42 apparently healthy individuals and 21 with beta-thalassemia minor) were analyzed at the Universidad Nacional de Tucumán, Argentina, between September 2013 and June 2014. A complete blood count, hemoglobin electrophoresis in alkaline pH and hemoglobin A2 levels were quantified. Moreover, thiobarbituric acid reactive species, erythrocyte catalase activity and iron status were evaluated. Beta-thalassemia mutations were determined by real-time polymerase chain reaction. FoxO3 gene expression was investigated by real-time reverse transcription-polymerase chain reaction using mononuclear cells from peripheral blood. Results: Subjects were grouped as children (≤12 years), and adult women and men. The analysis of erythrocyte catalase activity/hemoglobin ratio revealed a significant difference (p-value <0.05) between healthy and beta-thalassemia minor adults, but no significant difference was observed in the thiobarbituric acid reactive species levels and FoxO3 gene expression (p-value >0.05). Thiobarbituric acid reactive species and the erythrocyte catalase activity/hemoglobin ratio were not significantly different on comparing the type of beta-thalassemia mutation (β0 or β+) present in carriers. Conclusions: The lack of systemic oxidative imbalance demonstrated by thiobarbituric acid reactive species is correlated to the observation of normal FoxO3 gene expression in mononuclear cells of peripheral blood. However, an imbalanced antioxidant state was shown by the erythrocyte catalase activity/hemoglobin ratio in beta-thalassemia minor carriers. It would be necessary to study FoxO3 gene expression in reticulocytes to elucidate the role of FoxO3 in this pathology.

Mutational Profile of Homozygous ß-Thalassemia in Rio de Janeiro, Brazil.

ß-Thalassemia (ß-thal) is a hemolytic anemia that is caused by point mutations in most cases. The Brazilian population is highly heterogeneous and knowledge of the mutations that make up the genotypic profile of individuals can contribute information about the formation of the population and clinical condition of patients. In this study, we evaluated the mutations present in homozygous ß-thal patients from Rio de Janeiro, Brazil. We analyzed 24 samples of peripheral blood of patients with homozygous ß-thal. To identify the mutations, we carried out allele-specific-polymerase chain reaction (AS-PCR) and DNA sequencing. We found 11 different mutations on the ß-globin gene. Among the most frequent mutations observed were HBB: c.92 + 6T>C, followed by HBB: c.93-21G>A, HBB: c.118C>T and HBB: c.92 + 1G>A. We also identified the rare mutation HBB: c.75T>A that was reported in an individual carrying Hb S (HBB: c.20A>T)/ß-thal (HBB: c.75T>A) but not in Brazilian thalassemic patients, thus, this is the first report of this mutation in Brazilian ß-thal patients. For its multiethnic character, Brazil has different mutations that cause ß-thal and that are distributed with different frequencies according to the regions of the country. Our findings contribute to the description of the mutational profile of Brazilian thalassemic patients, showing wide heterogeneity and genetic variability.

[Beta thalassemia major and pregnancy during adolescence: report of two cases]. / Talassemia beta maior e gestação na adolescência: relato de dois casos.

Beta thalassemia major is a rare hereditary blood disease in which impaired synthesis of beta globin chains causes severe anemia. Medical treatment consists of chronic blood transfusions and iron chelation. We describe two cases of adolescents with beta thalassemia major with unplanned pregnancies and late onset of prenatal care. One had worsening of anemia with increased transfusional requirement, fetal growth restriction, and placental senescence. The other was also diagnosed with hypothyroidism and low maternal weight, and was admitted twice during pregnancy due to dengue shock syndrome and influenza H1N1-associated respiratory infection. She also developed fetal growth restriction and underwent vaginal delivery at term complicated by uterine hypotonia. Both patients required blood transfusions after birth and chose medroxyprogesterone as a contraceptive method afterwards. This report highlights the importance of medical advice on contraceptive methods for these women and the role of a specialized prenatal follow-up in association with a hematologist.

Talassemia beta maior e gestação na adolescência: relato de dois casos / Beta thalassemia major and pregnancy during adolescence: report of two cases

A talassemia beta maior é uma doença hematológica hereditária rara em que deficiência na síntese de cadeias globínicas beta causa anemia grave. O tratamento consiste de transfusão sanguínea e quelação de ferro. Descrevemos dois casos de adolescentes com talassemia beta maior, com gestação não planejada e início tardio de pré-natal. Uma delas apresentou piora da anemia, necessidade transfusional aumentada, restrição de crescimento fetal e senescência placentária. A outra apresentava também hipotireoidismo e baixo peso materno, e foi internada por duas ocasiões durante a gestação, por choque hemorrágico do dengue e por infecção respiratória associada a vírus influenza H1N1. Uma delas apresentou restrição de crescimento fetal e teve parto vaginal no termo complicado com hipotonia uterina. Ambas necessitaram de transfusão sanguínea no pós-parto e optaram por medroxiprogesterona como método contraceptivo subsequentemente. Esse relato ressalta a importância de orientação contraceptiva para essas mulheres e o papel do cuidado pré-natal especializado em conjunto com hematologista.

Beta thalassemia major is a rare hereditary blood disease in which impaired synthesis of beta globin chains causes severe anemia. Medical treatment consists of chronic blood transfusions and iron chelation. We describe two cases of adolescents with beta thalassemia major with unplanned pregnancies and late onset of prenatal care. One had worsening of anemia with increased transfusional requirement, fetal growth restriction, and placental senescence. The other was also diagnosed with hypothyroidism and low maternal weight, and was admitted twice during pregnancy due to dengue shock syndrome and influenza H1N1-associated respiratory infection. She also developed fetal growth restriction and underwent vaginal delivery at term complicated by uterine hypotonia. Both patients required blood transfusions after birth and chose medroxyprogesterone as a contraceptive method afterwards. This report highlights the importance of medical advice on contraceptive methods for these women and the role of a specialized prenatal follow-up in association with a hematologist.

Echocardiography in thalassemic patients on blood transfusions and chelation without heart failure.

BACKGROUND: Patients with thalassemia major present chronic hemolysis and require regular blood transfusions which may cause iron overload cardiomyopathy and chronic heart failure. Hemochromatosis is characterized by excessive iron accumulation in tissues, and heart involvement is the main cause of death in patients with thalassemia. OBJECTIVE: The aim of this study was to evaluate cardiac structure and function by conventional Doppler echocardiography and tissue Doppler imaging in patients with TM and no clinical evidence of heart failure. METHODS: This is a prospective observational study including 18 patients with thalassemia major (TM) receiving regular blood transfusion. To separately evaluate anemia and blood transfusion effects, two gender, age, weight, and height-matched control groups were included: one with healthy individuals (Healthy, n=18) and one with iron deficient anemia patients (Anemia, n=18). Statistical analysis was performed using ANOVA followed by Tukey's test or Kruskal-Wallis's and Dunn's test. RESULTS: The following echocardiographic variables presented significantly higher values in TM than the Anemia and Healthy groups: left atrium volume index (Healthy: 16.4±6.08; Anemia: 17.9±7.02; TM: 24.1±8.30 cm³/m²); mitral septal E/Em ratio (Healthy: 6.55±1.60; Anemia: 6.74±0.74; TM: 8.10±1.31); and duration of reverse pulmonary vein flow [Healthy: 74.0 (59.0-74.0); Anemia: 70.5 (67.0-74.0); TM: 111 (87.0-120) ms]. The mitral E/A ratio was higher in TM than Anemia (Healthy: 1.80±0.40; Anemia: 1.80±0.24; TM: 2.03±0.34). No differences were found in left ventricular structures and systolic function indexes. CONCLUSION: Conventional Doppler echocardiography and tissue Doppler allow changes in left ventricular diastolic function to be identified in asymptomatic patients with thalassemia major.

Liver fibrosis in young Egyptian beta-thalassemia major patients: relation to hepatitis C virus and compliance with chelation.

BACKGROUND: The main causes of liver fibrosis in transfusion-dependent thalassemia major are hepatitis C virus (HCV) infection and hepatic iron overload. The study aimed to assess liver fibrosis in Egyptian adolescents and young adult poly-transfused beta thalassemia patients infected with HCV using liver FibroScan in relation to iron overload and Liver iron concentration (LIC). MATERIAL AND METHODS: Fifty-one regularly transfused beta thalassemia patients above 12 years old were subjected to measurement of serum alanine transaminase (ALT), serum ferritin (SF), HCV (antibody and RNA), LIC assessed by hepatic R2* and transient elastography (TE) (FibroScan). FibroTest and liver biopsy were done to 25 patients. RESULTS: Eighty two% of studied thalassemia patients were HCV antibody positive; 21(49%) of them were viremic (HCV RNA positive); median LIC was 12 mg/gm dry weight. There were strong positive correlation between the degree of liver stiffness and Ishak fibrosis score assessed in liver biopsy specimens (P = 0.002) and between FibroScan and FibroTest results (P < 0.001). Patients with HCV viremia showed significantly higher ALT, γ-glutamyl transpeptidase (GGT), SF, LIC and increased liver stiffness compared to patients with no viremia (P = 0.0001, 0.001, 0.012, 0.006 and 0.001) respectively. Liver cirrhosis (TE values > 12.5kPa) was encountered in 23.5% and variable degrees of liver fibrosis (TE values > 6-12.5 kPa) in 35% of studied thalassemic patients. CONCLUSION: Young beta thalassemia patients with active hepatitis C infection may have hepatic cirrhosis or fibrosis at young age when accompanied with hepatic siderosis. Non invasive Liver FibroScan and Fibro-Test were reliable methods to assess liver fibrosis in young thalassemic-patients.

Ecocardiografia de pacientes talassêmicos sem insuficiência cardíaca em tratamento com transfusões sanguíneas e quelação / Echocardiography in thalassemic patients on blood transfusions and chelation without heart failure

FUNDAMENTO: Pacientes com talassemia major (TM) apresentam hemólise crônica e necessitam de transfusões sanguíneas egularmente que podem causar cardiomiopatia por sobrecarga de ferro e insuficiência cardíaca crônica. A hemocromatose é caracterizada por acúmulo excessivo de ferro nos tecidos; acometimento do coração é a principal causa de óbito em pacientes com talassemia. OBJETIVO: Avaliar as estruturas e a função cardíaca por meio de ecocardiografia com Doppler convencional e Doppler tecidual em pacientes com TM, sem evidência clínica de insuficiência cardíaca. MÉTODOS: Trata-se de estudo observacional prospectivo de 18 pacientes com TM que recebem transfusão sanguínea regularmente. Para avaliar, separadamente, os efeitos da anemia e da transfusão sanguínea, dois grupos controles pareados por gênero, idade, peso e altura foram incluídos: um com indivíduos saudáveis (Saudável, n = 18) e outro com pacientes com anemia por deficiência de ferro (Anemia, n = 18). Análise estatística foi realizada utilizando ANOVA seguida pelo teste de Tukey ou Kruskal-Wallis e teste de Dunn. RESULTADOS: As seguintes variáveis ecocardiográficas apresentaram valores significativamente mais elevados no grupo TM do que nos grupos Anemia e Saudável: índice de volume do átrio esquerdo (Saudável: 16,4 ± 6,08; Anemia: 17,9 ± 7,02; TM: 24,1 ± 8,30 cm/m); razão E/Em septal mitral (Saudável: 6,55 ± 1,60; Anemia: 6,74 ± 0,74; TM: 8,10 ± 1,31) e duração do fluxo reverso em veias pulmonares [Saudável: 74,0 (59,0-74,0); Anemia: 70,5 (67,0-74,0); TM: 111 (87,0-120) ms]. Arazão E/A mitral foi maior no grupo TM do que no grupo Anemia (Saudável: 1,80 ± 0,40; Anemia: 1,80 ± 0,24; TM: 2,03 ± 0,34). Não foram encontradas diferenças entre os grupos em variáveis estruturais do ventrículo esquerdo e em índices de função sistólica. CONCLUSÃO: A ecocardiografia com Doppler convencional e o Doppler tecidual permite que alterações na função diastólica do ventrículo esquerdo sejam identificadas em pacientes assintomáticos com talassemia major.

BACKGROUND: Patients with thalassemia major present chronic hemolysis and require regular blood transfusions which may cause iron overload cardiomyopathy and chronic heart failure. Hemochromatosis is characterized by excessive iron accumulation in tissues, and heart involvement is the main cause of death in patients with thalassemia. OBJECTIVE: The aim of this study was to evaluate cardiac structure and function by conventional Doppler echocardiography and tissue Doppler imaging in patients with TM and no clinical evidence of heart failure. METHODS: This is a prospective observational study including 18 patients with thalassemia major (TM) receiving regular blood transfusion. To separately evaluate anemia and blood transfusion effects, two gender, age, weight, and height-matched control groups were included: one with healthy individuals (Healthy, n=18) and one with iron deficient anemia patients (Anemia, n=18). Statistical analysis was performed using ANOVA followed by Tukey's test or Kruskal-Wallis's and Dunn's test. RESULTS: The following echocardiographic variables presented significantly higher values in TM than the Anemia and Healthy groups: left atrium volume index (Healthy: 16.4±6.08; Anemia: 17.9±7.02; TM: 24.1±8.30 cm³/m²); mitral septal E/Em ratio (Healthy: 6.55±1.60; Anemia: 6.74±0.74; TM: 8.10±1.31); and duration of reverse pulmonary vein flow [Healthy: 74.0 (59.0-74.0); Anemia: 70.5 (67.0-74.0); TM: 111 (87.0-120) ms]. The mitral E/A ratio was higher in TM than Anemia (Healthy: 1.80±0.40; Anemia: 1.80±0.24; TM: 2.03±0.34). No differences were found in left ventricular structures and systolic function indexes. CONCLUSION: Conventional Doppler echocardiography and tissue Doppler allow changes in left ventricular diastolic function to be identified in asymptomatic patients with thalassemia major.

The experience of thalassemic adults with their treatment.

This study, based on medical anthropology and oral reports, analyzes the meanings attributed by thalassemic adults to their experiences with the treatment. Interviews were used to collect data, which were analyzed through inductive thematic analysis. Eleven young adults, six of whom were men, at different ages, with different educational levels and occupations participated in the study. The meanings are discussed through the theme "the lives of patients with thalassemia in relation to their treatment". This core meaning highlights the difference made in their identity by having the disease trait, the recognition of the importance of adhering to their treatment, the difficulties in maintaining their social functions, the patients' irregular treatment adherence and their justifications for non-adherence to their treatment. Thalassemic patients conform to their condition and employ a normalization strategy to control the disease and justify irregular treatment adherence.

The experience of thalassemic adults with their treatment / A experiência dos talassêmicos adultos ao tratamento / La experiencia de los talasémicos adultos con su tratamiento

This study, based on medical anthropology and oral reports, analyzes the meanings attributed by thalassemic adults to their experiences with the treatment. Interviews were used to collect data, which were analyzed through inductive thematic analysis. Eleven young adults, six of whom were men, at different ages, with different educational levels and occupations participated in the study. The meanings are discussed through the theme "the lives of patients with thalassemia in relation to their treatment". This core meaning highlights the difference made in their identity by having the disease trait, the recognition of the importance of adhering to their treatment, the difficulties in maintaining their social functions, the patients' irregular treatment adherence and their justifications for non-adherence to their treatment. Thalassemic patients conform to their condition and employ a normalization strategy to control the disease and justify irregular treatment adherence.

O objetivo neste estudo foi analisar os sentidos dados pelos talassêmicos adultos à sua experiência em relação ao tratamento, com base na antropologia médica e no método do relato oral. Para a coleta de dados, usaram-se entrevistas e seguiu-se a análise temática indutiva. Participaram onze adultos jovens, seis do sexo masculino; com idades, níveis educacionais e profissões distintas. Os sentidos são apresentados pelo tema "a vida do portador de talassemia com o tratamento". O tema destacou a identidade de diferença pelo traço da doença, o reconhecimento da importância da adesão ao tratamento, as dificuldades em manterem suas funções sociais, os episódios de irregularidade na terapia e suas justificativas. Apreendeu-se que os portadores estão resignados com sua condição, empregam a estratégia de normalização para o controle da doença e justificaram a irregularidade no tratamento.

El objetivo de este estudio fue analizar los sentidos dados por los talasémicos adultos a su experiencia con el tratamiento, con base en la antropología médica y en el método del relato oral. Para la recolección de datos usamos entrevistas y seguimos el análisis temático inductivo. Participaron once adultos jóvenes, seis del sexo masculino; con edades, niveles educacionales y profesiones, distintas. Los sentidos da la experiencia son presentados por el tema "La vida del portador de talasemia con el tratamiento". El tema destaca la identidad de ser diferente por: el trazo de la enfermedad, el reconocimiento de la importancia de la adhesión al tratamiento, las dificultades en mantener sus funciones sociales y los episodios de irregularidad en la terapia y sus justificaciones. Aprendimos que los portadores están resignados con su condición y emplean la estrategia de normalización para el control de la enfermedad y para justificar la irregularidad en el tratamiento.

The genetics of blood disorders: hereditary hemoglobinopathies.

OBJECTIVE: To summarize recently published data on the pathophysiology, diagnosis and treatment of sickle cell diseases and beta-thalassemias, the most relevant hereditary hemoglobinopathies in the global population. SOURCES: Searches were run on the MEDLINE and SCIELO databases, limited to the period from 2003 to May 2008, using the terms hereditary hemoglobinopathies, sickle cell diseases and beta-thalassemia. Two books and two chapters were also included. SUMMARY OF THE FINDINGS: More than 2,000 articles were identified; those providing the most important information and broadest views were selected. CONCLUSIONS: Morbidity and mortality rates from sickle cell diseases and beta-thalassemia are still very high and represent an important challenge. Increased understanding of pathophysiological aspects has lead to significant improvements in treatment and prevention of these diseases.

Genética das doenças hematológicas: as hemoglobinopatias hereditárias: [revisão] / The genetics of blood disorders: hereditary hemoglobinopathies: [review]

OBJETIVO: Sumarizar os dados disponíveis na literatura recente sobre os aspectos fisiopatológicos, de diagnóstico e tratamento das doenças falciformes e da talassemia β, hemoglobinopatias hereditárias de maior relevância nas populações. FONTES DOS DADOS: MEDLINE e SciELO, utilizando os termos hemoglobinopatias hereditárias, doenças falciformes e talassemia beta, no período de 2003 a maio de 2008. Dois livros e dois capítulos de livro foram também incluídos. SÍNTESE DOS DADOS: Foram encontrados mais de 2.000 artigos, sendo selecionados aqueles de maior pertinência e amplitude. CONCLUSÕES: As taxas de morbidade e a mortalidade das doenças falciformes e da talassemia β são ainda bastante expressivas e constituem importante desafio. Um maior conhecimento dos mecanismos fisiopatológicos tem permitido avanços significativos nas formas de tratamento e prevenção dessas doenças.

OBJECTIVE: To summarize recently published data on the pathophysiology, diagnosis and treatment of sickle cell diseases and β-Thalassemias, the most relevant hereditary hemoglobinopathies in the global population. SOURCES: Searches were run on the MEDLINE and SCIELO databases, limited to the period from 2003 to May 2008, using the terms hereditary hemoglobinopathies, sickle cell diseases and β-thalassemia. Two books and two chapters were also included. SUMMARY OF THE FINDINGS: More than 2,000 articles were identified; those providing the most important information and broadest views were selected. CONCLUSIONS: Morbidity and mortality rates from sickle cell diseases and β-thalassemia are still very high and represent an important challenge. Increased understanding of pathophysiological aspects has lead to significant improvements in treatment and prevention of these diseases.

Urinary iron excretion induced by intravenous infusion of deferoxamine in beta-thalassemia homozygous patients.

The purpose of the present study was to identify noninvasive methods to evaluate the severity of iron overload in transfusion-dependent beta-thalassemia and the efficiency of intensive intravenous therapy as an additional tool for the treatment of iron-overloaded patients. Iron overload was evaluated for 26 beta-thalassemia homozygous patients, and 14 of them were submitted to intensive chelation therapy with high doses of intravenous deferoxamine (DF). Patients were classified into six groups of increasing clinical severity and were divided into compliant and non-compliant patients depending on their adherence to chronic chelation treatment. Several methods were used as indicators of iron overload. Total gain of transfusion iron, plasma ferritin, and urinary iron excretion in response to 20 to 60 mg/day subcutaneous DF for 8 to 12 h daily are useful to identify iron overload; however, urinary iron excretion in response to 9 g intravenous DF over 24 h and the increase of urinary iron excretion induced by high doses of the chelator are more reliable to identify different degrees of iron overload because of their correlation with the clinical grades of secondary hemochromatosis and the significant differences observed between the groups of compliant and non-compliant patients. Finally, the use of 3-9 g intravenous DF for 6-12 days led to a urinary iron excretion corresponding to 4.1 to 22.4% of the annual transfusion iron gain. Therefore, continuous intravenous DF at high doses may be an additional treatment for these patients, as a complement to the regular subcutaneous infusion at home, but requires individual planning and close monitoring of adverse reactions.

Blood group genotyping facilitates transfusion of beta-thalassemia patients.

We evaluated the usefulness of blood group genotyping as a supplement to hemagglutination to determine the red blood cell (RBC) antigen profile of polytransfused patients with beta-thalassemia. We selected 10 alloimmunized patients who were receiving antigen-matched RBCs based on phenotype, and had clinical evidence of delayed hemolytic transfusion reaction. DNA was prepared from blood samples and RH E/e, K1/K2, FY A/FY B, and JK A/JK B alleles were determined by PCR-RFLP. RH D/non-D was determined according to the PCR product size associated with the RHD gene sequence in intron 4 and exon 10/3'UTR. RH C/c was tested by multiplex PCR. The phenotypes and genotypes of nine of the 10 samples were discrepant. Five of the discrepancies occurred in the Rh system. One sample was phenotyped as Rhcc and genotyped as RH C/C, and two samples were phenotyped as RhCc and genotyped as RH C/C. Two other samples were phenotyped as RhEe and genotyped as RH e/e. Three samples had discrepancies in the Kidd system with phenotype Jk(a+b+) and were genotyped as homozygous for JK B. One sample had a discrepancy in the Duffy system: it was phenotyped as Fy(a+b-) and homozygous for FY B. Genotyping was very important in determining the true blood groups of many polytransfused patients with beta-thalassemia, and it assisted in the identification of suspected alloantibodies and the selection of antigen-negative RBCs for transfusion.

[Viral seroprevalence, transfusion and alloimmunization in adults with sickle cell anemia in Guadeloupe]. / Séroprévalence virale, transfusion et allo-immunisation chez des adultes drépanocytaires guadeloupéens.

We retrospectively studied the prevalence of anti HIV 1 and 2, anti-HTLV-I, anti-Hepatitis B and C viruses (HBV and HCV) antibodies, anti-HBV vaccinal coverage, transfused patients and alloimmunizations frequencies among adult sickle cell patients attending the sickle cell center (SCC) of Guadeloupe. The data were collected from the medical files of the centre. Among the studied samples (n = 331) no transfusional HIV contamination was observed. All patients with HTLV-I (n = 11, 3.3% of whole sample) and anti-HCV (n = 9, 2.7%) positive serology had transfusion history. Five patients (1.5%) had an active hepatitis B. Vaccination against HBV efficiently protected 247 patients (74.4%) and 57 had post-hepatitis B antibodies. We observed that 213 patients (64%) had a history of transfusion (88% of SS patients and 36% of the SC patients, p < 0.05). Fifty-four patients (16%) presented alloimmunization, 4 of them have never been transfused. These results show that it is still necessary to optimise transfusion protocol and their safety, and to diagnose viral contamination in transfused sickle cell patients.