Diversity of variant alleles encoding Kidd, Duffy, and Kell antigens in individuals with sickle cell disease using whole genome sequencing data from the NHLBI TOPMed Program.

BACKGROUND: Genetic variants in the SLC14A1, ACKR1, and KEL genes, which encode Kidd, Duffy, and Kell red blood cell antigens, respectively, may result in weakened expression of antigens or a null phenotype. These variants are of particular interest to individuals with sickle cell disease (SCD), who frequently undergo chronic transfusion therapy with antigen-matched units. The goal was to describe the diversity and the frequency of variants in SLC14A1, ACKR1, and KEL genes among individuals with SCD using whole genome sequencing (WGS) data. STUDY DESIGN AND METHODS: Two large SCD cohorts were studied: the Recipient Epidemiology and Donor Evaluation Study III (REDS-III) (n = 2634) and the Outcome Modifying Gene in SCD (OMG) (n = 640). Most of the studied individuals were of mixed origin. WGS was performed as part of the National Heart, Lung, and Blood Institute's Trans-Omics for Precision Medicine (TOPMed) program. RESULTS: In SLC14A1, variants included four encoding a weak Jka phenotype and five null alleles (JKnull ). JKA*01N.09 was the most common JKnull . One possible JKnull mutation was novel: c.812G>T. In ACKR1, identified variants included two that predicted Fyx (FY*X) and one corresponding to the c.-67T>C GATA mutation. The c.-67T>C mutation was associated with FY*A (FY*01N.01) in four participants. FY*X was identified in 49 individuals. In KEL, identified variants included three null alleles (KEL*02N.17, KEL*02N.26, and KEL*02N.04) and one allele predicting Kmod phenotype, all in heterozygosity. CONCLUSIONS: We described the diversity and distribution of SLC14A1, ACKR1, and KEL variants in two large SCD cohorts, comprising mostly individuals of mixed ancestry. This information may be useful for planning the transfusion support of patients with SCD.

Diversity of RH and transfusion support in Brazilian sickle cell disease patients with unexplained Rh antibodies.

BACKGROUND: Genetic diversity in the RH genes among sickle cell disease (SCD) patients is well described but not yet extensively explored in populations of racially diverse origin. Transfusion support is complicated in patients who develop unexpected Rh antibodies. Our goal was to describe RH variation in a large cohort of Brazilian SCD patients exhibiting unexpected Rh antibodies (antibodies against RH antigens to which the patient is phenotypically positive) and to evaluate the impact of using the patient's RH genotype to guide transfusion support. STUDY DESIGN AND METHODS: Patients within the Recipient Epidemiology and Evaluation Donor Study (REDS)-III Brazil SCD cohort with unexpected Rh antibodies were selected for study. RHD and RHCE exons and flanking introns were sequenced by targeted next-generation sequencing. RESULTS: Fifty-four patients with 64 unexplained Rh antibodies were studied. The majority could not be definitively classified as auto- or alloantibodies using serologic methods. The most common altered RH were RHD*DIIIa and RHD*DAR (RHD locus) and RHCE*ce48C, RHCE*ce733G, and RHCE*ceS (RHCE locus). In 53.1% of the cases (34/64), patients demonstrated only conventional alleles encoding the target antigen: five of 12 anti-D (41.7%), 10 of 12 anti-C (83.3%), 18 of 38 anti-e (47.4%), and one of one anti-E (100%). CONCLUSION: RHD variation in this SCD cohort differs from that reported for African Americans, with increased prevalence of RHD*DAR and underrepresentation of the DAU cluster. Many unexplained Rh antibodies were found in patients with conventional RH allele(s) only. RH genotyping was useful to guide transfusion to determine which patients could potentially benefit from receiving RH genotyped donor units.

Eu3+ -tetrakis ß-diketonate complexes for solid-state lighting application.

Eu3+ -ß-diketonate complexes are used, for example, in solid-state lighting (SSL) or light-converting molecular devices. However, their low emission quantum efficiency due to water molecules coordinated to Eu3+ and low photostability are still problems to be addressed. To overcome such challenges, we synthesized Eu3+ tetrakis complexes based on [Q][Eu(tfaa)4 ] and [Q][Eu(dbm)4 ] (Q1 = C26 H56 N+ , Q2 = C19 H42 N+ , and Q3 = C17 H38 N+ ), replacing the water molecules in the tris stoichiometry. The tetrakis ß-diketonates showed desirable thermal stability for SSL and, under excitation at 390 nm, they displayed the characteristic Eu3+ emission in the red spectral region. The quantum efficiencies of the dbm complexes achieved values as high as 51%, while the tfaa complexes exhibited lower quantum efficiencies (28-33%), but which were superior to those reported for the tris complexes. The structures were evaluated using the Sparkle/PM7 model and comparing the theoretical and the experimental Judd-Ofelt parameters. [Q1][Eu(dbm)4 ] was used to coat a near-UV light-emitting diode (LED), producing a red-emitting LED prototype that featured the characteristic emission spectrum of [Q1][Eu(dbm)4 ]. The emission intensity of this prototype decreased only 7% after 30 h, confirming its high photostability, which is a notable result considering Eu3+ complexes, making it a potential candidate for SSL.

Effect of Convalescent Plasma in Critically Ill Patients With COVID-19: An Observational Study.

Background: Convalescent plasma is a potential therapeutic option for critically ill patients with coronavirus disease 19 (COVID-19), yet its efficacy remains to be determined. The aim was to investigate the effects of convalescent plasma (CP) in critically ill patients with COVID-19. Methods: This was a single-center prospective observational study conducted in Rio de Janeiro, Brazil, from March 17th to May 30th, with final follow-up on June 30th. We included 113 laboratory-confirmed COVID-19 patients with respiratory failure. Primary outcomes were time to clinical improvement and survival within 28 days. Secondary outcomes included behavior of biomarkers and viral loads. Kaplan-Meier analyses and Cox proportional-hazards regression using propensity score with inverse-probability weighing were performed. Results: 41 patients received CP and 72 received standard of care (SOC). Median age was 61 years (IQR 48-68), disease duration was 10 days (IQR 6-13), and 86% were mechanically ventilated. At least 29 out of 41CP-recipients had baseline IgG titers ≥ 1:1,080. Clinical improvement within 28 days occurred in 19 (46%) CP-treated patients, as compared to 23 (32%) in the SOC group [adjusted hazard ratio (aHR) 0.91 (0.49-1.69)]. There was no significant change in 28-day mortality (CP 49% vs. SOC 56%; aHR 0.90 [0.52-1.57]). Biomarker assessment revealed reduced inflammatory activity and increased lymphocyte count after CP. Conclusions: In this study, CP was not associated with clinical improvement or increase in 28-day survival. However, our study may have been underpowered and included patients with high IgG titers and life-threatening disease. Clinical Trial Registration: The study protocol was retrospectively registered at the Brazilian Registry of Clinical Trials (ReBEC) with the identification RBR-4vm3yy (http://www.ensaiosclinicos.gov.br).

Brazilian Guidelines for transcranial doppler in children and adolescents with sickle cell disease.

BACKGROUND: Sickle cell disease is the most common monogenic hereditary disease in Brazil. Although strokes are one of the main causes of morbidity and mortality in these patients, the use of transcranial Doppler to identify children at risk is not universally used. OBJECTIVE: To develop Brazilian guidelines for the use of transcranial Doppler in sickle cell disease children and adolescents, so that related health policies can be expanded, and thus contribute to reduce morbidity and mortality. METHODS: The guidelines were formulated in a consensus meeting of experts in transcranial Doppler and sickle cell disease. The issues discussed were previously formulated and scientific articles in databases (MEDLINE, SciELO and Cochrane) were carefully analyzed. The consensus for each question was obtained by a vote of experts on the specific theme. RESULTS: Recommendations were made, including indications for the use of transcranial Doppler according to the sickle cell disease genotype and patients age; the necessary conditions to perform the exam and its periodicity depending on exam results; the criteria for the indication of blood transfusions and iron chelation therapy; the indication of hydroxyurea; and the therapeutic approach in cases of conditional transcranial Doppler. CONCLUSION: The Brazilian guidelines on the use of transcranial doppler in sickle cell disease patients may reduce the risk of strokes, and thus reduce the morbidity and mortality and improve the quality of life of sickle cell disease patients.

Brazilian Guidelines for transcranial doppler in children and adolescents with sickle cell disease

BACKGROUND: Sickle cell disease is the most common monogenic hereditary disease in Brazil. Although strokes are one of the main causes of morbidity and mortality in these patients, the use of transcranial Doppler to identify children at risk is not universally used. OBJECTIVE: To develop Brazilian guidelines for the use of transcranial Doppler in sickle cell disease children and adolescents, so that related health policies can be expanded, and thus contribute to reduce morbidity and mortality. METHODS: The guidelines were formulated in a consensus meeting of experts in transcranial Doppler and sickle cell disease. The issues discussed were previously formulated and scientific articles in databases (MEDLINE, SciELO and Cochrane) were carefully analyzed. The consensus for each question was obtained by a vote of experts on the specific theme. RESULTS: Recommendations were made, including indications for the use of transcranial Doppler according to the sickle cell disease genotype and patients age; the necessary conditions to perform the exam and its periodicity depending on exam results; the criteria for the indication of blood transfusions and iron chelation therapy; the indication of hydroxyurea; and the therapeutic approach in cases of conditional transcranial Doppler. CONCLUSION: The Brazilian guidelines on the use of transcranial doppler in sickle cell disease patients may reduce the risk of strokes, and thus reduce the morbidity and mortality and improve the quality of life of sickle cell disease patients.

[Neonatal screening for hemoglobinopathies in Rio de Janeiro, Brazil]. / Triagem neonatal para hemoglobinopatias no Rio de Janeiro, Brasil.

OBJECTIVE: To describe the main results obtained in the first 15 months of neonatal screening for sickle cell disease in the state of Rio de Janeiro, Brazil, from August 2000 to November 2001. METHODS: Starting in August 2000, blood samples began to be collected for sickle cell disease screening from all newborns receiving care in primary health care clinics in the state of Rio de Janeiro. The samples were submitted to high-resolution liquid chromatography. If the resulting chromatogram was compatible with sickle cell disease, the child and the parents were referred for diagnostic confirmation and treatment. RESULTS: Between August 2000 and November 2001, 99 260 newborns were screened. There was one case of homozygous Hb C. On average, one of every 27 newborns who were screened presented sickle cell trait (Hb AS). Sickle cell disease was observed in 83 cases, or one new case in each 1 196 births. The 83 consisted of: 62 Hb S, 18 Hb SC, and 3 Hb SD. One child did not appear for diagnostic confirmation. The 82 children who were followed up by the program presented 15 intercurrent illnesses (upper respiratory infections, fever, splenic sequestration crises, hand-foot syndrome, and vascular occlusion), resulting in seven hospital admissions. Blood transfusions were necessary with 15 children, but none developed alloimmunization. All the other babies were doing well with the use of prophylactic penicillin. CONCLUSIONS: Our data show the importance of early diagnosis for sickle cell disease, so as to prevent the frequent infectious complications faced by these patients.

Desempenho da tecnologia dos eritrócitos magnetizados (EM® Technology) nos testes imunoematológicos / Erythrocytes magnetized technology (EM® Technology) performance in immunohematology assays

A tecnologia dos eritrócitos magnetizados (E.M.®Technology) é uma grande inovação nos ensaios imunoematológicos. Os testes são realizados manualmente na estação detrabalho Freelys®Nano ou no equipamento automatizado Qwalys® (Diagast, Loos, France). O método utiliza hemácias magnetizadas e uma placa magnética substitui a centrifugação. As microplacas para a classificação sangüínea e fenotipagem Rh e K contêm anti-soros monoclonais IgM. As microplacas destinadas a pesquisa de anticorpos irregulares (PAI) e prova cruzada (PC) contêm antiglobulina humana (AGH) monoclonalmurina: anti-IgG na PAI e na PC anti-IgG + anti-IgM de baixo título para detectar anticorpos ABO. Na PAI e na PC, as reações acontecem na camada contendo AGH (imunocaptura) e visa detectar anticorpos IgG. A utilização de um meio de alta densidade possibilita a utilização da AGH sem lavagens prévias. Na avaliação da E.M.®Technology na classificação sangüínea, Fenotipagem, PAI e PC, na estação Freelys®Nano, foram utilizadas amostras de pacientes, doadores, sangue de cordão, hemácias de pacientes com teste de Coombs direto positivo e concentrados de hemácias. Todas as amostras foram paralelamente testadas em gel-teste (Diamed e Grifols). A concordância entre a E.M.®Technology e o gel-teste foi: 100% na classificação ABO e RhD e na fenotipagem Rh/ K, 94,6% na PAI e 92,3% na PC. A sensibilidade da E.M.®Technology na detecção de anticorpos IgG foi 95,5% em ambos os métodos. A E.M.®Technology mostrou um bom desempenho nos testes efetuados.

The erythrocytes magnetized technology (E.M.® Technology) is a great innovation in the field of blood banking. The tests can be performed manually on a Freelys® Nano workstation or on thefully-automated system QWALYS® (Diagast, Loos, France). This method does not require centrifugation steps thanks to the use of magnetic red blood cells and a magnetic plate. For blood grouping and Rh/K phenotyping, the microplate contains monoclonal IgMantibodies. The wells of the microplate to perform antibody screening and cross-matching are coated with murine monoclonal anti-human globulin: anti-IgG for antibody screening and anti-IgG + anti-IgM for cross-matching. The E.M.® Technology is only able to detectIgG antibodies. A high-density medium layer avoids the necessity of rinsing before the antiglobulin reagent. To evaluate the performance of E.M.® Technology on a Freelys® Nano work station for blood grouping, Rh/K phenotyping, antibody screening and crossmatching, we selected samples from patients, blood donors, blood cords, red blood cells from patients with positive direct antiglobulin test (DAT) and red blood cells from storage blood bags. In parallel, the tests were performed using the gel-technique (Diamed and Grifols). The concordance between E.M.® Technology and gel-testwas 100% for blood grouping and Rh/K phenotyping, 94.6% for antibody screening and 92.3% for cross-matching. The sensitivity to detect IgG antibodies was 95.5% in both methods. The E.M.® Technology on a Freelys® Nano workstation provided good resultsin all the tests performed.

Triagem neonatal para hemoglobinopatias no Rio de Janeiro, Brasil / Neonatal screening for hemoglobinopathies in Rio de Janeiro, Brazil

OBJETIVO: Descrever os principais resultados do programa de triagem neonatal para a doença falciforme do Estado do Rio de Janeiro em 15 meses de funcionamento (agosto de 2000 a novembro de 2001). MÉTODOS: A partir de agosto de 2000, amostras de sangue passaram a ser coletadas de todos os recém-nascidos atendidos em postos de atençäo básica à saúde no Estado para triagem neonatal da doença falciforme. Essas amostras säo submetidas a cromatografia líquida de alta resoluçäo. Se o cromatograma resultante for compatível com a doença falciforme, a criança e seus pais säo encaminhados para confirmaçäo diagnóstica e tratamento. RESULTADOS: De agosto de 2000 a novembro de 2001, 99 260 recém nascidos participaram da triagem. Houve um caso de homozigose para Hb C. Um em cada 27 recém-nascidos triados pelo programa apresentou o traço falciforme (Hb AS). A doença falciforme foi constatada em 83 casos (um caso novo para cada 1 196 nascimentos): 62 Hb S, 18 Hb SC, 3 Hb SD. Uma criança näo compareceu para confirmaçäo diagnóstica. As 82 crianças acompanhadas apresentaram 15 intercorrências (infecçöes de vias aéreas superiores, febre, seqüestro esplênico, síndrome mäo-pé e crises de vaso-oclusäo), motivando sete internaçöes. Houve necessidade de transfusäo sangüínea em 15 crianças, mas nenhuma tornou-se alo-imunizada. Os demais bebês estäo evoluindo satisfatoriamente com o uso de penicilina profilática. CONCLUSÖES: Nossos dados evidenciam a importância do diagnóstico precoce da doença falciforme, de forma a prevenir e evitar as freqüentes complicaçöes infecciosas enfrentadas por esses pacientes

Contribuiçäo ao estudo do papel da hemodiálise na transmissäo da hepatite C / Contribution to the study of role of hemodialisis in the transmission of hepatitis C

Foi estudado o papel dos procedimentos hemodialíticos como possível rota de transmissao da infecçao pelo vírus C da hepatite. Analisando a sorologia de 281 pacientes, comparada à de 57 outros, estudados previamente, verificamos soropositividade em percentual superior ao dos relatos na literatura (43,41 por cento), havendo correlaçao positiva entre a soropositividade e o uso de hemotransfusoes prévias. A taxa de soropositividade entre os pacientes que nunca receberam hemotransfusoes (9,02 por cento) parece indício de que o equipamento empregado na hemodiálise possa servir de rota transmissora na infecçao pelo vírus C da hepatite.