Genetic prediction of 33 blood group phenotypes using an existing genotype dataset.

BACKGROUND: Accurate blood type data are essential for blood bank management, but due to costs, few of 43 blood group systems are routinely determined in Danish blood banks. However, a more comprehensive dataset of blood types is useful in scenarios such as rare blood type allocation. We aimed to investigate the viability and accuracy of predicting blood types by leveraging an existing dataset of imputed genotypes for two cohorts of approximately 90,000 each (Danish Blood Donor Study and Copenhagen Biobank) and present a more comprehensive overview of blood types for our Danish donor cohort. STUDY DESIGN AND METHODS: Blood types were predicted from genome array data using known variant determinants. Prediction accuracy was confirmed by comparing with preexisting serological blood types. The Vel blood group was used to test the viability of using genetic prediction to narrow down the list of candidate donors with rare blood types. RESULTS: Predicted phenotypes showed a high balanced accuracy >99.5% in most cases: A, B, C/c, Coa /Cob , Doa /Dob , E/e, Jka /Jkb , Kna /Knb , Kpa /Kpb , M/N, S/s, Sda , Se, and Yta /Ytb , while some performed slightly worse: Fya /Fyb , K/k, Lua /Lub , and Vel ~99%-98% and CW and P1 ~96%. Genetic prediction identified 70 potential Vel negatives in our cohort, 64 of whom were confirmed correct using polymerase chain reaction (negative predictive value: 91.5%). DISCUSSION: High genetic prediction accuracy in most blood groups demonstrated the viability of generating blood types using preexisting genotype data at no cost and successfully narrowed the pool of potential individuals with the rare Vel-negative phenotype from 180,000 to 70.

Estimated prevalence of the Duffy null phenotype Fy (a-b-) among black blood-donors in Southwestern Colombia.

INTRODUCTION: Hemolytic reactions are adverse complications associated with red blood cell transfusion. These reactions are associated with clinically important erythrocyte antigens, such as those of Duffy blood Meny (2010). Individuals with the Duffy null phenotype Fy (a-b-) are more likely to develop an alloimmunization reaction, resulting in an incompatibility with all available red blood cell units, thus increasing the risk of complications from their underlying disease Höher et al. (2018). Hence, it is important to determine the prevalence of the Fy (a-b-) phenotype in blood donors in our population and to create a database to ensure safe transfusion in patients with this phenotype. Moreover, we intend to establish whether there is any relationship between individuals with this phenotype and the sickle cell trait. We conducted this study to measure the prevalence of the Fy (a-b-) phenotype in our blood donors. MATERIALS AND METHODS: This prospective, descriptive study included black blood donors visiting the blood bank of a tertiary care university hospital between January 2019 and July 2019. We used Fitzpatrick classification phototype VI and self-identification to select donors in the study. The presence of the Duffy antigens Fya and Fyb was determined by the Coombs test using monoclonal antibodies. To establish the presence of hemoglobin S (HbS) and sickle cell traits, a hemoglobin electrophoresis test was performed. RESULTS: We included 166 patients in the study. Seventy-nine donors were identified as having Fy (a-b-). The prevalence of the Fy (a-b-) phenotype was 48 %. Sickle cell trait hemoglobinopathy was found in 6 blood donors (8%). CONCLUSION: This information is relevant for the implementation of a database of blood donors to guarantee the safety of transfusion in patients with a Fitzpatrick skin type 6at our institution. Moreover, it may provide information of interest to other blood banks in case donors with this phenotype are needed. No significant association was found between the donor Fy (a-b-) phenotype and the sickle cell trait.

Antibody screening in multitransfused patients: a prerequisite before each transfusion.

Life-long red blood cell (RBC) transfusions remain the main treatment for severe thalassemia. We hereby report a case of anti S and anti Lu(a) in a ß-thalassemia major patient detected incidentally on antibody screening. The patient was a known case of ß-thalassemia major and was on regular blood transfusion every 3 weeks from the institute from the age of 6 months. Subsequently, on one occasion, patient's crossmatch was compatible despite positive antibody screen using microcolumn gel technique. Autocontrol and direct antiglobulin test were negative on microcolumn gel. Anti S and anti Lu(a) antibodies were identified. Blood unit found compatible was negative for S and Lu(a) antigens. Antibody titers were 1:1 for both anti S and anti Lu(a) in AHG phase using tube technique and antibodies were of IgG type. Blood unit was transfused uneventfully to the patient. Donors were traced back (last three donations) and called for repeat blood sample testing for S and Lu(a) antigen. Two out of three donors were found to be S antigen positive and one out of these two was Lu(a) antigen positive. Anti S and anti Lu(a) antibodies were again identified on patient's subsequent visit for transfusion. The present case re-emphasize the importance of antibody screening at each visit in earlier detection of antibodies in multi transfused patients. Encouraging patients to receive transfusion from one center and dedicating donors could reduce alloimmunization rate but larger studies are required.

Next Generation Sequencing of Red Blood Cell Antigens in Transfusion Medicine: Systematic Review and Meta-Analysis.

Molecular analysis of blood groups is important in transfusion medicine, allowing the prediction of red blood cell (RBC) antigens. Many blood banks use single nucleotide variant (SNV) based methods for blood group analysis. While this is a well-established approach, it is limited to the polymorphisms included in genotyping panels. Thus, variants that alter antigenic expression may be ignored, resulting in incorrect prediction of phenotypes. The popularization of next-generation sequencing (NGS) has led to its application in transfusion medicine, including for RBC antigens determination. The present review/meta-analysis aimed to evaluate the applicability of the NGS for the prediction of RBC antigens. A systematic review was conducted following a comprehensive literature search in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Studies were selected based on predefined criteria and evaluated using Strengthening the Reporting of Observational studies in Epidemiology guidelines. The characteristics and results of the studies were extracted and meta-analysis was performed to verify the agreement between results from standard molecular methods and NGS. Kell (rs8176058), Duffy (rs2814778, rs12078), or Kidd (rs1085396) alleles were selected as a model for comparisons. Additionally, results are presented for other blood group systems. Of the 864 eligible studies identified, 10 met the inclusion criteria and were selected for meta-analysis. The pooled concordance proportion for NGS compared to other methods ranged from 0.982 to 0.994. The sequencing depth coverage was identified as crucial parameters for the reliability of the results. Some studies reported difficulty in analyzing more complex systems, such as Rh and MNS, requiring the adoption of specific strategies. NGS is a technology capable of predicting blood group phenotypes and has many strengths such as the possibility of simultaneously analyzing hundred individuals and gene regions, and the ability to provide comprehensive genetic analysis, which is useful in the description of new alleles and a better understanding of the genetic basis of blood groups. The implementation of NGS in the routine of blood banks depends on several factors such as cost reduction, the availability of widely validated panels, the establishment of clear quality parameters and access to bioinformatics analysis tools that are easy to access and operate.

Screening and identification of unexpected red cell antibodies by simultaneous LISS/Coombs and NaCl/Enzyme gel methods.

We evaluated the clinical usefulness of simultaneous LISS/Coombs and NaCl/Enzyme testing using the gel method for screening and identification of unexpected antibodies in 15,014 samples. When unexpected antibodies were detected by either screening test, those antibodies were identified using both the LISS/Coombs and the NaCl/Enzyme gel test. The positive screening rates of the LISS/Coombs, NaCl/Enzyme, and combined tests (excluding 25 autoantibody cases) were 0.48%, 1.29%, and 1.39%, respectively. Among the 57 samples positive by both screening methods, the antibodies in 19.3% could be identified only by the NaCl/Enzyme method. Among the 137 samples positive only by NaCl/Enzyme screening, 74.5% showed positive results in antibody identification only by the NaCl/Enzyme test, although 7.3% were also positive in the LISS/Coombs test. The NaCl/Enzyme method thus showed about threefold higher detection rates than the LISS/Coombs method, especially in screening for Rh antibodies, and higher exact identification rates and discriminatory power for identifying mixed antibodies. Addition of the NaCl/Enzyme method to routine laboratory procedures may detect and identify considerable numbers of significant antibodies that might be missed if only the LISS/Coombs method is used.

Specificities and isotypes of erythrocytes autoantibodies in patients with warm autoimmune hemolytic anemia / Especificidades e isotipos de autoanticuerpos eritrocitarios en pacientes con anemia hemolítica autoinmune caliente

Introduction: Autoimmune hemolytic anemia is a rare disorder characterized by hemolysis mediated by autoantibodies directed against red blood cells. The demonstration of antibody specificity is a very difficult procedure since autoantibodies in general are nonspecific of antigens and react with all erythrocytes analyzed. Occasionally, specificity is observed against the Rh system antigens. Objective: To determinate the specificity of erythrocytes autoantibodies in DAT positive autoimmune hemolytic anemia by MAIEA technique. Methods: The specificity and isotype of erythrocyte autoantibodies were determined in the eluate of 109 blood samples from patients with warm autoimmune hemolytic anemia, by means of the MAIEA technique and the use of monoclonal antibodies that recognized 11 blood group systems and the protein CD47. Results: In 100 percent of cases autoantibodies against Rh system antigens were detected; in 24 cases we detected autoantibodies of IgA and IgM isotypes that recognized different antigens that were recognized by IgG isotype autoantibodies. For idiopathic and secondary warm autoimmune hemolytic anemias, predominance was observed against three or more specificities. IgG was detected in 99.09 percent of the eluates, IgA in 35.77 percent and IgM in 16.51 percent. The high degree of hemolysis was related to the presence of several isotype autoantibodies against four or more blood group specificities. Conclusions: The MAIEA technique is a sensitive method that can be used to determine the specificities and isotypes of autoantibodies in patients with warm autoimmune hemolytic anemia.

Introducción: La anemia hemolítica autoinmune es un trastorno poco común, caracterizado por hemólisis mediada por autoanticuerpos dirigidos contra los glóbulos rojos. La demostración de la especificidad de los anticuerpos es un procedimiento muy difícil, ya que los autoanticuerpos en general no son específicos de los antígenos y reaccionan con todos los eritrocitos analizados. Ocasionalmente, se observa especificidad contra los antígenos del sistema Rh. Objetivo: Determinar la especificidad de los autoanticuerpos eritrocitarios en pacientes con anemias hemolíticas autoinmunes PAD positivas con el empleo de la técnica MAIEA Métodos: Se determinó la especificidad e isotipo de los autoanticuerpos eritrocitarios en el eluido de 109 muestras de sangre de pacientes con anemia hemolítica autoinmune caliente, mediante la técnica de MAIEA y el uso de anticuerpos monoclonales que reconocieron 11 sistemas de grupos sanguíneos y la proteína CD47. Resultados: En el ciento por ciento de los casos se detectaron autoanticuerpos contra los antígenos del sistema Rh. En 24 casos se descubrió autoanticuerpos de isotipos IgA e IgM que reconocieron diferentes antígenos que fueron a su vez reconocidos por autoanticuerpos de isotipo IgG. Se observó para las anemias hemolíticas autoinmunes calientes idiopáticas y secundarias; predominio frente a tres o más especificidades. Se detectó IgG en el 99,09 por ciento de los eluidos, IgA en 35,77 por ciento e IgM en 16,51 por ciento. El alto grado de hemólisis se relacionó con la presencia de varios isotipos de autoanticuerpos contra cuatro o más especificidades de grupos sanguíneos. Conclusiones: La técnica MAIEA es un método sensible que puede usarse para determinar las especificidades e isotipos de autoanticuerpos en pacientes con anemia hemolítica autoinmune caliente.

Imunohematologia veterinária: antígenos eritrocitários caninos / Veterinary immunohematology: canine erythrocyte antigen / Inmunohematología veterinaria: antígenos eritrocitarios caninos

A imunohematologia veterinária vem ganhando interesse nos últimos anos devido a maior acessibilidade a tecnologias de detecção de antígenos e anticorpos, interesse dos donos e médicos veterinários em buscar uma melhor qualidade de vida para os animais e as necessidades de transfusões com o menor índice possível de reações indesejadas. Os cães possuem antígenos presentes na membrana de suas células vermelhas, podendo causar reações durante e após transfusões. Diferentemente de humanos e felinos, cães não possuem anticorpos naturais para os principais antígenos, a priori podendo ser transfundidos com qualquer tipo sanguíneo sem consequências posteriores, porém, se submetidos a uma segunda transfusão, sendo essa de um tipo sanguíneo incompatível e previamente sensibilizados, as chances de ocorrer reações transfusionais graves aumentam drasticamente, ocasionando danos ao animal, podendo levá-lo à morte. Por conta desses riscos se faz necessário uma maior atenção aos tipos sanguíneos desses animais onde 8 sistemas são reconhecidos internacionalmente classificados como sistema DEA, sendo eles DEA 1 e seus subtipos (DEA 1.1; DEA1.2; DEA 1.3); DEA 3; DEA 4; DEA 5; DEA 6; DEA 7 e DEA 8, e recentemente um novo sistema denominado Dal. Não há disponível ainda soros para os sistemas DEA 6 e DEA 8, tornando a pesquisa sobre esses antígenos dificultosa.(AU)

Veterinary immunohematology is gaining interest in recent years due to greater accessibility to antigen and antibody detection technologies, the interests of pet owners and veterinarians in seeking a better quality of life for animals, and requirement of transfusions with the lowest possible rate of collateral reactions. Dogs have antigens present in the membrane of their red blood cells that can cause reactions during and after transfusions. Unlike humans and cats, dogs do not have natural antibodies to the key antigens, and a priori they can be transfused with any type of blood without any further consequences. However, if they are ever subjected to a second transfusion, if using incompatible blood types and being previously sensitized, the likelihood of having serious transfusion reactions drastically increase, causing damage to the animal, which may even lead it to death. Due to those risks, greater attention is required to the blood type of those animals, which present 8 systems, internationally recognized and classified as the DEA system, namely DEA 1 and its subtypes (DEA 1.1; DEA 1.2; DEA 1.3); DEA 3; DEA 4; DEA 5; DEA 6; DEA 7 and DEA 8, and recently a new system referred to as Dal. No serum is yet available for DEA 6 and DEA 8 systems, hindering the research on those antigens.(AU)

La inmunohematología veterinaria ha ganado atención en los últimos años debido mayor accesibilidad a tecnologías de detección de antígenos y anticuerpos, interés de dueños y médicos veterinarios en buscar mejor calidad de vida para los animales y las necesidades de transfusiones con menor índice posible de reacciones indeseadas. Los perros poseen antígenos presentes en la membrana de sus células rojas, pudiendo causar reacciones durante y después de transfusiones. Diferentemente de humanos y felinos, perros no tienen anticuerpos naturales para los principales antígenos, a priori, pudiendo ser transfundidos con cualquier tipo de sangre sin consecuencias posteriores, todavía, si sometidos a una segunda transfusión, siendo esa de un tipo sanguíneo incompatible y previamente sensibilizados, la posibilidad de ocurrir reacciones transfusional grave aumenta drásticamente, ocasionando daños al animal, pudiendo llevarlo a la muerte. Por esos riesgos se hace necesario más atención a los tipos sanguíneos de esos animales, donde 8 sistemas son reconocidos internacionalmente y clasificados como sistema DEA, siendo ellos DEA 1 y sus subtipos (DEA 1.1; DEA 1.2; DEA 1.3); DEA 3; DEA 4; DEA 5; DEA 6; DEA 7 y DEA 8, y recién un nuevo sistema denominado Dal. No hay aún disponible sueros para los sistemas DEA 6 y DEA 8, haciendo dificultosa la investigación sobre esos antígenos.(AU)

Frequência dos antígenos eritrocitários do sistema AB em felinos domésticos no estado da Paraíba / Frequency of AB blood System in domestic cats of Paraíba, Brazil

Objetivou-se com este estudo determinar a frequência de antígenos eritrocitários do sistema AB em felinos domésticos da Paraíba, Brasil. Foram selecionados aleatoriamente 178 gatos, clinicamente saudáveis, sem pré-requisitos quanto a sexo ou raça, com peso corporal acima de 1,5 kg e faixa etária acima de um ano de idade, abordados no ato da consulta ambulatorial em clínicas médicas de pequenos animais distribuídas entre três cidades da Paraíba (João Pessoa, Campina Grande e Patos). A determinação dos tipos sanguíneos foi realizada através do teste de hemaglutinação em tubo de ensaio e, a tipagem reversa foi realizada para as amostras tipos B e AB para confirmação e evidenciação de aloanticorpos naturais. Neste estudo a frequência relativa de antígenos eritrocitários A, B e AB em sua totalidade para felinos sem raça foram 98,1%, 1,21% e 0,69%, respectivamente. Todos os felinos com definição racial foram do tipo sanguíneo A. Diante destes, a probabilidade de ocorrência de reações transfusionais aleatórias obtidas foi de 2,78%, sendo cerca 40% (1,11%) potencialmente fatais. Desta forma, dado o conhecimento da frequência dos diferentes tipos sanguíneos em felinos, de uma determinada região, conclui-se que a tipagem sanguínea e o teste de compatibilidade, são importantes ferramentas que permitem ao médico veterinário tomar medidas preventivas que minimizem riscos de ocorrência de reações transfusionais e isoeletrólise neonatal e, estabelece pré-requisitos a respeito dos riscos de procedimentos hemoterápicos em felinos que circunstancialmente necessitem serem conduzidos de forma aleatória.

The objective of this study was to determine the frequency of the AB blood group antigens system in domestic cats of Paraíba, Brazil. We randomly selected 178 cats which were clinically healthy, with no prerequisites in terms of gender or race, weighing above 1.5 kg, and were over one year of age. These cats were randomly selected when they entered the small animal clinic facilities in the cities of João Pessoa, Campina Grande and Patos. The determination of blood types was made using the hemagglutination test tube, and the reverse typing was performed for samples B and AB types and for confirmation of alloantibodies natural disclosure. In this study the relative frequency of A, B and AB blood group antigens in cats without a determined breed was 98.1%, 1.21% and 0.69% respectively. All cats with breed definition were blood type A. The likelihood of random transfusion reactions was 2.78%, approximately 40% (1.11%) potentially fatal. Thus, given knowledge of the frequency of different blood types in cats, from a given region, it is concluded that blood typing and compatibility test are important tools that enable the veterinarian to take preventative measures to minimize risks of isoelectrolisys reactions and neonatal transfusion, and establishes prerequisites about the risks of hemotherapic procedures in cats that require circumstantially to be conducted randomly.