Novel KEL allele associated with loss of Kpb identified in a white blood donor.

The importance of identifying variant alleles among blood donors is significant to the safety of transfusion for recipients. Molecular methods have become more prominent in the routine process of antigen typing donor units. Some variant antigens cannot be detected using only serologic methods. Molecular testing allows the determination of nucleotide sequences that are used to predict a phenotype. Antigens of the Kell blood group system are known for being highly immunogenic and causing adverse reactions upon antibody formation. A female white blood donor who typed Kp(b-) using serologic methods on multiple donations since 2005 was the subject of a typing discrepancy investigation. Routine genotyping using a commercial genotyping kit (HemoID DQS Panel; Agena Bioscience, San Diego, CA) predicted the donor to type Kp(a+b+). Investigation of the discrepancy between these two results identified a rare single nucleotide variant in the KEL gene at nucleotide position c.948G>T that alters amino acid residue 316 from tryptophan (Trp) to cysteine (Cys). After discovery of the novel allele, adsorption and elution studies were performed to see if there was weakened Kpb expression. The elution studies yielded negative results, which indicated that Kpb is not expressed. The KEL transcripts expressed by the donor were determined using cDNA analysis, and the predicted amino acid sequence of the novel allele was modeled to investigate the impact of the amino acid sequence on the structure of the KEL polypeptide. Both SWISS-MODEL and Robetta software were used to evaluate the impact of the p.Trp316Cys on the three-dimensional protein structure. There was no conformational change noted with SWISS-MODEL, whereas the Robetta software showed a significant conformational change compared with the normal Kp(b+) reference sequence. Because the donor is homozygous for variants associated with k and Jsb expression, it was not possible to determine whether the novel allele is associated with loss of Kpb only or loss of all Kell antigens.

Análise do perfil de Rh e Kell em doadores de sangue em Porto Alegre, Rio Grande do Sul / Phenotypic profile analysis of Rh and Kell blood group systems among donors in Porto Alegre, Rio Grande do Sul

Introdução: A hemoterapia é uma prática terapêutica pelo meio de transfusão sanguínea. Devido ao baixo estoque de bolsas de sangue e o aumento de pacientes crônicos e emergenciais, se faz necessária a realização de testes imuno-hematológicos para minimizar os riscos de reações transfusionais e aloimunizações em doadores e receptores de sangue. Deste modo, no estudo foi avaliada a prevalência dos antígenos dos sistemas Rh e Kell em doadores de sangue de Porto Alegre ­ RS.Métodos: Estudo quantitativo, transversal e retrospectivo que foi realizado através da análise das informações dos doadores de sangue contidas no banco de dados do Hemocentro do Estado do Rio Grande do Sul, nos anos de 2018 e 2019.Resultados: Das 6.479 amostras fenotipadas, quanto ao sistema Rh, 44,6% são Rh positivo e 55,4% são Rh negativo. As frequências dos antígenos encontradas foram de, CC 10,1%, Cc 27%, cc 62,9%, EE 1,2%, Ee 13,9%, ee 84,9%. E, para o sistema Kell, K1 positivo 7,1% e K1 negativo 92,9%.Conclusões: Antígenos do sistema Rh e Kell exibem um grande nível de imunogenicidade e uma forte ligação com a Doença Hemolítica do Recém-nascido, podendo ocorrer a sensibilização em pacientes caso não haja a compatibilidade sanguínea. Este estudo ressalta a importância da implementação da fenotipagem eritrocitária em doadores de sangue, sugere-se mais estudos com períodos distintos para a pesquisa de resultados satisfatórios.

Introduction: Hemotherapy is a therapeutic practice consisting of blood transfusion. Low blood supply and an increase in chronic and emergency patients have made it necessary to conduct immunohematology tests to minimize the risks of adverse reactions and alloimmunization in donors and recipients. Therefore, this study aimed to assess the prevalence of Rh and Kell blood group antigens among blood donors in Porto Alegre, Rio Grande do Sul, Brazil.Methods: We conducted a quantitative, cross-sectional, retrospective study. Information from blood donors included in the Rio Grande do Sul's Blood Center database from 2018 to 2019 were analyzed.Results: A total of 6,479 samples were phenotyped, of which 44.6% were Rh-positive and 55.4% were Rh-negative. Antigen prevalence was CC (10.1%), Cc (27%), cc (62.9%), EE (1.2%), Ee (13.9%), and ee (84.9%). As for the Kell group, 7.1% were K1-positive and 92.9% were K1-negative.Conclusions: The Rh and Kell antigens are highly immunogenic and have a strong link with the hemolytic disease of the newborn. Sensitization may occur in patients if there is no blood compatibility. This study highlights the importance of implementing erythrocyte phenotyping in blood donors. Further studies should be conducted in different time frames to achieve satisfactory results.

Frequências fenotípicas dos sistemas de grupos sanguíneos ABO, Rh e Kell em doadores de sangue da região metropolitana de Belém-PA / Phenotype frequencies of ABO, Rh and Kell blood group systems in blood donors in the metropolitan region of Belém-PA

Objetivo: O objetivo deste trabalho foi realizar um estudo das frequências dos principais antígenos e fenótipos dos sistemas de grupo sanguíneo: ABO, Rh, Kell. Métodos: A partir dos dados da fenotipagem estendida disponíveis no Sistema de Banco de Sangue (SBS web) de doadores de sangue da Fundação Hemopa, foram avaliadas as frequências absolutas e relativas. Resultados: Dentre os 1.474 doadores analisados houve predominância do tipo O (62,6%) e quanto ao Rh: D (85,5%). O antígeno mais frequente do sistema Rh foi: e (94,9%), e o fenótipo mais frequente: DCcee (27,5%). O antígeno mais frequente do sistema Kell foi: Kpb (100%), e o fenótipo: k+ K- (95,7%), Kp (a- b+) (99,4%). Conclusão: A identificação das frequências desses antígenos em diferentes populações pode auxiliar na rotina hemoterápica, facilitando a busca por hemocomponentes compatíveis, melhorando a segurança transfusional imunológica.

Objective: To study the frequencies of the major antigens of bloodgroup systems:ABO, Rh, Kell. Methods: From data of extendedphenotyping available in the Blood Bank System (SBS web) in blooddonors of the Hemopa Foundation, were evaluated absolute and relativefrequencies. Results: Among the 1.474 donors analyzed there was apredominance of type O (62.6%) and RhD (85.5%). The most frequentantigen from system Rh was: e (94,9%), and the most commonphenotype: DCcee (27,5%). The most frequent antigen from systemKell was: Kpb (100%), and the most common phenotypes: k + K-(95.7%), Kp (a- b +) (99.4%). Conclusion: Identifying the frequenciesof these antigens in different populations may help in the routine bloodtherapy, facilitating the search for compatible blood components,improving the immunological transfusion safety.

First report of a KELnull phenotype in Peru and a lesson of invisible genetic disparity.

Blood banks in developing countries have limited capability to typify common blood groups creating disparities in the access to blood units for patients with rare blood genotypes. We report the case of a Peruvian woman with metastatic breast cancer with KELnull phenotype (K0), a rare blood group characterized by the lack of expression of all Kell antigens on the red blood cells (RBCs). The molecular studies identified that the patient's RBCs were homozygous for the nonsense c.1546C > T mutation predicted to encode p.Arg516Ter (KEL*02 N.17 allele), which confirmed the K0 phenotype. We conducted a local and international search of compatible blood units. Finally, the Japanese Red Cross donated the blood units for the patient. We present here the first report for a K0 phenotype in Peru and the challenging genetic disparities that many patients have to face to access to blood units in our country.

Frecuencia y procedencia del antígeno Kell en mujeres donantes de sangre durante los años 2016-2017 / Frequency and origin of the Kell antigen in female blood donors during 2016-2017

Resumen Introducción: El sistema Kell está formado por dos antígenos principales: el Kell (K) y el Cellano (k), estos son capaces de causar reacciones graves, tales como reacción hemolítica postransfusional y la enfermedad hemolítica del recién nacido. Los antígenos de este sistema son altamente inmunogénicos lo que les confiere el tercer lugar en importancia clínica. Objetivo: Determinar la frecuencia del antígeno Kell y procedencia de las mujeres donantes de sangre con antígeno Kell positivo en el Hemocentro del Centro Oriente Colombiano (HCOC). Metodología: Estudio descriptivo de corte transversal que incluyó 186 donantes voluntarias de sangre del Hemocentro Centro Oriente Colombiano, se realizó la fenotipificación del antígeno Kell, utilizando la técnica Aglutinación en lámina, la cual se basa en enfrentar glóbulos rojos del donante con anticuerpo monoclonal anti K. Se calculó la frecuencia fenotípica del antígeno Kell, en porcentajes y para el procesamiento de la información se utilizó el paquete estadístico SPSS versión 21.0 en español donde se realizó todo el análisis de los datos de la población. Resultados: Se procesaron 177 muestras obtenidas en 9 campañas de donación de sangre realizadas en diferentes municipios del departamento de Boyacá, obteniéndose una frecuencia fenotípica del 7,5% para el antígeno Kell, en la población de mujeres donantes de sangre del HCOC, siendo esta similar con la frecuencia encontrada en Colombia y Latinoamérica. Conclusión: Se determinó que la frecuencia del antígeno Kell en las mujeres donantes de sangre del HCOC fue del 7,5%, y se logró identificar que no existe una relación estadísticamente entre la procedencia y la presencia del antígeno Kell en las donantes, lo anterior está relacionado con el mestizaje y los procesos de migración.

Abstract Introduction: The Kell system consists of two major antigens: Kell (K) and Cellano (K), which are capable of causing serious reactions, such as posttransfusion hemolytic reaction and hemolytic disease of the newborn. The antigens of this system are highly immunogenic which gives them the third place in clinical importance. Objective: To determine the frequency of Kell antigen and origin of blood donors in the Hemocenter of the Centro Oriente Colombiano (H.C.O.C). Methods: Cross-sectional descriptive study involving 186 blood donors from the Centro Oriente Colombian Hemocenter, phenotyping of the Kell antigen was carried out, using the technique Aglutination in lamina, which is based on facing donor red blood cells with anti-K monoclonal antibody. Calculated the phenotypic frequency of the Kell antigen in percentages and for the processing of the information was used the statistical package SPSS version 21.0 in Spanish where all the analysis of the data of the population was carried out. Results: 177 samples obtained in 9 blood donation campaigns were carried out in different municipalities of the department of Boyacá, obtaining a phenotypic frequency of 7.5% for the Kell antigen in the population of female HCOC blood donors. Similar to the frequency found in Colombia and Latin America. Conclusion: It was determined that the frequency of Kell antigen in the female HCOC donors was 7.5%, and it was possible to identify that there is no statistically relation between the origin and the presence of Kell antigen in the donors, Is related to mestizaje and migration processes.

Febrile neutropenia following parvovirus B19 infection and cross anti-kell reaction to E. coli in pregnancy / Infeção por parvovírus B19 causando neutropenia febril e reação cruzada anti-Kell com E. coli na gravidez

Abstract Parvovirus B19 has tropism for red line blood cells, causing immune hydrops during pregnancy. A positive anti-Kell Coombs reaction usually happens during pregnancy when there is production of antibodies that target Kell antigens, but cross reactions to other antigens may occur. A 24-year-old Gypsy primigravida, 0 Rhesus positive, presented with persistent isolated hyperthermia for 2 weeks and a positive indirect Coombs test result with anti-Kell antibodies at routine tests. She had a 19-week live fetus. The blood tests revealed bicytopenia with iron deficiency anemia, leucopoenia with neutropenia, and elevated C-reactive protein. She was medicated with imipenem, and had a slow clinical recovery. Blood, urine and sputum samples were taken to perform cultures and to exclude other systemic infections. Escherichia coli was isolated in the urine, which most probably caused a transient cross anti-Kell reaction. Haemophilus influenza in the sputum and seroconversion to parvovirus B19 was confirmed, causing unusual deficits in the white cells, culminating in febrile neutropenia. Despite the patient's lack of compliance to the medical care, both maternal and fetal/neonatal outcomes were good. This a rare case report of 2 rare phenomena, a cross anti-Kell reaction to E. coli and parvovirus B19 infection with tropism for white cells causing febrile neutropenia, both events occurring simultaneously during pregnancy.

Resumo O parvovírus B19 tem tropismo para as células sanguíneas da linha vermelha, causando hidropsia imune durante a gravidez. O teste Coombs anti-Kell positivo ocorre durante a gravidez quando há produção de anticorpos contra os antígenos de Kell, mas pode haver reações cruzadas para outros antígenos. Uma grávida primigesta de etnia cigana, de 24 anos, 0 Rhesus positivo, recorreu ao hospital às 19 semanas de gestação por hipertermia isolada persistente por 2 semanas e umteste Coombs indireto positivo por anticorpos anti-Kell em testes de rotina da gravidez. O estudo analítico revelou bicitopenia com anemia ferropênica, leucopenia com neutropenia, e elevação da proteína C-reativa. A paciente foi medicada com imipenem, e teve uma recuperação clínica lenta. Foram colhidas amostras de sangue, urina e expectoração para culturas bacterianas. Na urina, foi isolada Escherichia coli, o que provavelmente causou a reação anti-Kell cruzada transitória. Na expectoração, foi isolada Haemophilus influenza, e foi confirmada seroconversão para o parvovírus B19, que causou um déficit incomum na linhagem sanguínea branca, culminando com neutropenia febril. Apesar da má adesão aos cuidados médicos, os desfechos materno e fetal/neonatal foram bons. Este é um caso de 2 fenômenos raros, uma reação cruzada anti-Kell à infecção por E. coli, e parvovírus B19 comtropismo para células brancas causando neutropenia febril, ambos ocorrendo simultaneamente durante a gravidez.

B cells require Type 1 interferon to produce alloantibodies to transfused KEL-expressing red blood cells in mice.

BACKGROUND: Alloantibodies to red blood cell (RBC) antigens can cause significant hemolytic events. Prior studies have demonstrated that inflammatory stimuli in animal models and inflammatory states in humans, including autoimmunity and viremia, promote alloimmunization. However, molecular mechanisms underlying these findings are poorly understood. Given that Type 1 interferons (IFN-α/ß) regulate antiviral immunity and autoimmune pathology, the hypothesis that IFN-α/ß regulates RBC alloimmunization was tested in a murine model. STUDY DESIGN AND METHODS: Leukoreduced murine RBCs expressing the human KEL glycoprotein were transfused into control mice (WT), mice lacking the unique IFN-α/ß receptor (IFNAR1-/- ), or bone marrow chimeric mice lacking IFNAR1 on specific cell populations. Anti-KEL IgG production, expressed as mean fluorescence intensity (MFI), and B-cell differentiation were examined. RESULTS: Transfused WT mice produced anti-KEL IgG alloantibodies (peak response MFI, 50.4). However, the alloimmune response of IFNAR1-/- mice was almost completely abrogated (MFI, 4.2; p < 0.05). The response of bone marrow chimeric mice lacking IFNAR1 expression in all hematopoietic cells or specifically in B cells was also diminished (MFI, 3.8 and 5.4, respectively, compared to control chimeras, MFI, 65.6; p < 0.01). Accordingly, transfusion-induced differentiation of IFNAR1-/- B cells into germinal center B cells and plasma cells was significantly reduced, compared to WT B cells. CONCLUSIONS: This study demonstrates that B cells require signaling from IFN-α/ß to produce alloantibodies to the human KEL glycoprotein in mice. These findings provide a potential mechanistic basis for inflammation-induced alloimmunization. If these findings extend to human studies, patients with IFN-α/ß-associated conditions may have an elevated risk of alloimmunization and benefit from personalized transfusion protocols.

Phenotyping Rh/Kell and risk of alloimmunization in haematological patients.

BACKGROUND: One of the biggest concerns in transfusion medicine is to avoid red blood cell alloimmunization. We evaluated the rate of alloimmunization in two groups of chronically transfused patients (A - not phenotyped and B - phenotyped for Rh/K antigens before the first transfusion) with primary haematological disorders and its distribution among the main haematological diseases, in order to adopt an efficient transfusional strategy. STUDY DESIGN AND METHODS: As methodology, we used the SIBAS and SAM databases for the retrospective study of all patients with primary haematological disorder between January 2011 and April 2013. RESULTS: A statistical difference in the rate of alloimmunization comparing groups A and B was found (P <0·0001). We also observed that alloimmunization was not homogeneously distributed in all primary haematological diseases. CONCLUSIONS: The Rh/K phenotype should be performed on all patients diagnosed with bone marrow failure, plasma cell dyscrasia and myelodysplastic syndrome in order to avoid alloimmunization. In patients with acute leukaemia and lymphoma it seems not necessary to perform it. In patients with haemoglobinopathy and myeloproliferative disorders, a larger group of patients is needed to decide its efficacy.

Frequencies of polymorphisms of the Rh, Kell, Kidd, Duffy and Diego systems of Santa Catarina, Southern Brazil

Background Red blood cell genes are highly polymorphic with the distribution of alleles varying between different populations and ethnic groups. The objective of this study was to investigate gene polymorphisms of blood groups in the state of Santa Catarina, Southern Brazil. Methods Three hundred and seventy-three unrelated blood donors and 31 transfusion-dependent patients were evaluated to investigate polymorphisms of the Rh, Kell, Duffy, Kidd, and Diego blood group systems in a population from the state of Santa Catarina. The subjects, from seven regions that comprise the blood-banking network of the state, were assessed between August 2011 and March 2014. The genotypes of the Rh, Kell, Duffy, Kidd, and Diego systems were determined using the restriction fragment length polymorphism-polymerase chain reaction and allele-specific polymerase chain reaction techniques. Results The genotype frequencies in this study were significantly different when populations from different regions of Santa Catarina were compared. Furthermore, there were also significant differences in the genetic frequencies compared to other Brazilian states. The genotype frequencies of the Kell and Kidd blood groups are similar to European populations from Naples, Italy and Zurich, Switzerland. Conclusion This article reports for the first time the frequency of polymorphisms of blood group systems in blood donors from Santa Catarina, Southern Brazil.

Distribution of Kell phenotype among pregnant women in Sokoto, North Western Nigeria.

INTRODUCTION: Kell antigen is highly immunogenic and is the common cause of antibody production in mismatched blood transfusions, haemolytic transfusion reaction (HTR) and maternal alloimmunization, which causes severe anaemia in neonates. The aim of this study is to determine the prevalence and ethnic variation of the Kell phenotype among pregnant women in Sokoto, Nigeria. METHODS: Kell antigen status of 150 pregnant women aged 18-45 years and mean age 27.19 ±4.69 years attending antenatal clinic in UDUTH Sokoto Nigeria was determined using the conventional tube method and anti-Kell reagents (Lorne Laboratories, UK). RESULTS: Among the 150 subjects studied, 3 (2.0%) of subjects were positive and 147 (98.0) were negative for K antigen. Of the 150 pregnant subjects; 32 (21.3%) were primigravidae while 118 (78.7%) were multigravidae. Kell phenotype was more prevalent among primigravidae (3.1%) compared to multigravidae (1.7%) women. The distribution of Kell phenotype among the pregnant subjects was compared based on ethnicity. The prevalence of Kell antigen was significantly higher among the Hausa ethnic group (3.2%) compared to other ethnic groups which indicated zero prevalence (p = 0.001). Kell negative phenotype was ≥ 96.8% among all the ethnic groups. CONCLUSION: Our observed prevalence of Kell phenotype is consistent with previous studies among Blacks and Asians but significantly lower than values observed in previous studies among Caucasians. We recommend that all pregnant women should be screened for the presence clinically significant red cell antigens including Kell antigen on their first antenatal visit. Kell negative red cell should be routinely provided for all pregnant women and women with child bearing potential to reduce the risk of Kell-associated HDFN. There is need to introduce routine screening of pregnant women for clinically significant red cell antibodies to facilitate the effective management of HDFN as well as prevent HTR. There is also need for sustained health education of pregnant women in the area to encourage early booking for antenatal care.

Frecuencia de antígenos del sistema sanguíneo Rh y del sistema Kell en donantes de sangre / Frequency of antigens in Rh and Kell blood system in blood donors

Introducción: los estudios inmunohematológicos que se realizan a los donantes de sangre se orientan a proporcionar al receptor una terapia transfusional compatible con el sistema sanguíneo ABO y antígeno D del sistema Rh. Sin embargo, como una forma de incrementar la seguridad transfusional, surge el interés de ampliar la gama de antígenos a determinar y por ende, a compatibilizar previo a una transfusión sanguínea. Objetivo: determinar la frecuencia de los cinco antígenos mayores del sistema Rh y los antígenos K1 y K2 del sistema Kell en donantes voluntarios de sangre. Métodos: Estudio descriptivo transversal que incluyó 200 donantes voluntarios de sangre del Centro Productivo Regional de Sangre del Maule (CPRSM) seleccionados al azar. Se realizó fenotipificación de los cinco antígenos mayores del sistema Rh. y el antígeno K1 y K2 del sistema Kell. Se utilizó la técnica de hemaglutinación en tubo, con sueros monoespecíficos y DG Gel® Coombs. Se calculó la frecuencia fenotípica de los antígenos D, C, c, E y e del sistema Rh., y K1 y K2 del sistema Kell, en porcentajes. A partir de la frecuencia de los fenotipos Rh. se determinó la frecuencia del genotipo más probable de dicho sistema. Para el Kell se estimó el genotipo en base al fenotipo. Resultados: sistema Rh: 96 por ciento de las muestras estudiadas presentaba el antígeno D, 97,5 por ciento el antígeno e; 35,5 por ciento el antígeno E; 79 por ciento el antígeno C y 65,5 por ciento el antígeno c. El genotipo más frecuente fue CDe/CDe. Sistema Kell: se encontró una frecuencia del 4 por ciento para el antígeno K1, mientras que el antígeno K2 presenta una frecuencia del 99,5 por ciento. Al nivel de frecuencia genotípica se detectó que el 96 por ciento de la población tiene un genotipo homocigoto para K2 (kk). Conclusiones: La frecuencias de los siete antígenos estudiados es similar a la descrita en otras poblaciones(AU)

Introduction: Immunologic studies performed on blood donors are directed to provide a transfusion therapy compatible with ABO blood group system and Rh system D antigen in the recipient. However, as a way to increase transfusion safety, the interest of expanding the range of antigens to determine and therefore to be tested for compatibility prior to a blood transfusion, arises. Aim: To determine the frequency of the five major antigens of Rh. system and K1 and K2 antigens of the Kell system in blood donors. Methods: Cross-sectional study including 200 randomly selected voluntary blood donors from Centro Productivo Regional de Sangre del Maule (CPRSM). Phenotyping of five major antigens of Rh. system and K1 and K2 Kell system antigens was carried out. The tube hemagglutination technique with monospecific Coombs sera and DG Gel ® was used. The Rh. system D, C, c, E, e antigens and Kell system K1 and K2 antigen phenotypic frequencies were calculated in percentages. The most likely Rh.genotype was determined from the phenotype frequency of this system. Similarly, in Kell system the genotype frequency was determined based on phenotype. Results: In the Rh.system, 96 percent of the samples studied had D antigen; 97.5 percent had the e antigen, and 35.5 percent the E antigen. Antigen C was present in 79 percent and c in 65.5 percent. The most frequent Rh. genotype was CDe/CDe. In Kell system, K1 antigen presented a frequency of 4 percent, while antigen K2 presented a 99.5 percent. Regarding genotypic frequency, a 96 percent of the population showed a K2 (kk) homozygous genotype(AU) Conclusion: The frequency of the seven antigens studied is similar to that described in other populations(AU)

Bilateral cystic encephalomalacia following multiple intrauterine transfusions for anti-Kell isoimmunisation.

Fetal and neonatal haemolytic diseases result from maternal allo-immunisation to fetal antigens. Maternal antibodies cross the placenta causing red cell haemolysis, resulting in fetal anaemia and, in severe cases, hydrops and perinatal death. Intravascular intrauterine blood transfusion (IUT) has markedly reduced perinatal mortality and is now a standard procedure. IUT is considered to be a safe procedure with fetal loss rate reported to be less than 5% and no reported increase in the rate of neurodevelopment impairment. In this report, we are presenting a case of bilateral cystic encephalomalacia following fetal anaemia secondary to anti-Kell iso-immunisation treated with multiple IUTs. Such a significant adverse outcome following IUT for anti-Kell iso-immunisation has not been reported in the literature. This case highlights the need for appropriate parental counselling and routine postnatal head ultrasound in all babies delivered following multiple IUTs.

Provision of KEL1-negative blood to obstetric patients: a 3-year single-institution retrospective review.

BACKGROUND: KEL1 alloimmunization is a major cause of hemolytic disease of the fetus and newborn (HDFN). While select countries have guidelines for preventing transfusion-associated KEL1 alloimmunization, the United States does not. Beth Israel Deaconess Medical Center instituted a policy in April 2009 whereby women not more than 50 years of age on the obstetric service were transfused KEL1-negative red blood cells (RBCs). We sought to determine compliance and impact for prevention of KEL1 alloimmunization and HDFN. STUDY DESIGN AND METHODS: All women not more than 50 years of age without anti-K transfused RBCs during an obstetric admission from April 9, 2009, to April 9, 2012, were identified (227). Adherence to policy, factors contributing to nonadherence, and subsequent impact were evaluated. For comparison, all cases of anti-K detection in women not more than 50 years of age admitted to nonobstetric services and all cases of transfusion-associated KEL1 alloimmunization in women not more than 50 years of age during the 10 years prior were identified. RESULTS: Eighty-four percent received only KEL1-negative units. Three (1.3%) women not more than 50 years of age on the obstetric service were identified with anti-K, while 17 (1.5%) women not more than 50 years of age on nonobstetric services had anti-K detected; only five of 20 had a prior RBC transfusion. In the 10 years prior, there were 27 cases of transfusion-associated KEL1 alloimmunization in women not more than 50 years of age. There were no cases of KEL1 HDFN in either period. CONCLUSION: Although the findings demonstrate feasibility of providing KEL1-negative RBCs to women of childbearing potential, evidence for clinical benefit is lacking. The low prevalence of KEL1 in blood donors, the lack of significant differences in alloimmunization rates, and no cases of HDFN during the study period questions the clinical benefit of such a policy.

[Sickle cell anemia and transfusion safety in Bamako, Mali. Seroprevalence of HIV, HBV and HCV infections and alloimmunization belonged to Rh and Kell systems in sickle cell anemia patients]. / Sécurité transfusionnelle et drépanocytose à Bamako, Mali. Séroprévalence des infections à VIH, VHB, VHC et allo-immunisation anti-Rh et Kell chez les drépanocytaires.

Red cell transfusion is one of the main treatments in sickle cell disease. However there are potential risks of blood transfusions. In order to propose strategies to improve blood safety in sickle cell disease in Mali, we conducted a prospective study of 133 patients with sickle cell anemia recruited at the sickle cell disease research and control center of Bamako, November 2010 to October 2011. The study aimed to determine the prevalence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infections by serum screening and the frequency of red cell alloimmunization before and after blood transfusion. The diagnosis of sickle cell syndrome was made by HPLC, the detection of markers of viral infection was performed by ELISA, and the diagnosis of alloimmunization was conducted by the Indirect Coombs test. Prevalence of viral infections observed at the time of enrolment of patients in the study was 1%, 3% and 1% respectively for HIV, HBV and HCV. Three cases of seroconversion after blood transfusion were detected, including one for HIV, one for HBV and one another for HCV in sickle cell anemia patients. All these patients had received blood from occasional donors. The red cell alloimmunization was observed in 4.4% of patients. All antibodies belonged to Rh system only. Blood transfusion safety in sickle cell anemia patients in Mali should be improved by the introduction of at least the technique for detecting the viral genome in the panel of screening tests and a policy of transfusions of blood units only from regular blood donors.

Ablation of the Kell/Xk complex alters erythrocyte divalent cation homeostasis.

XK is a putative transporter of unknown function that is ubiquitously expressed and linked through disulfide bonds to Kell protein, an endothelin-3 (ET-3)-converting enzyme. We generated three knockout (KO) mice that lacked either Xk, Kell or both proteins and characterized erythrocyte cation levels, transport and hematological parameters. Absence of Xk or Kell was accompanied by changes in erythrocyte K(+), Mg(2+), Na(+) and Ca(2+) transport that were associated with changes in mean cellular volume and corpuscular hemoglobin concentration mean. Baseline Ca(2+)-ATPase activity was undetected in erythrocytes from all three mouse types but was restored upon pre-incubation with ET-3. Consistent with these alterations in Ca(2+) handling, we observed increased Gardos channel activity in Kel and Xk KO mice. In addition Kel deletion was associated with increased Mg(2+) permeability while Xk deletion blocked Na/Mg exchanger activity. Our results provide evidence that cellular divalent cation regulation is functionally coupled to the Kell/XK system in erythrocytes and loss of this complex may contribute to acanthocytosis formation in McLeod syndrome.

Premio Dr. Antonio Pérez Prado - XIV Congreso Argentino de Medicina Transfusional. Isoinmunización por anti-K1: manejo clínico e inmunohematológico de 30 casos / Dr. Antonio Pérez prado Award - XIV Argentine Congress of Transfusion Medicine. Anti K1 isoimmunization: clinical and immunohematological management of 30 cases

Introducción: La principal causa de anemia fetal es la inmunización por anticuerpos (Acs.) anti-D. La inmunización por anti-K1 es poco frecuente aunque puede producir un cuadro de anemia fetal muy grave. Su incidencia relativa ha aumentado en los últimos años por el aumento de las transfusiones sanguíneas y por disminución de la inmunización anti-D. Presentamos el seguimiento obstétrico e inmunohematológico de 30 casos de gestantes sensibilizadas por anti-Kl. Objetivo: mostrar nuestra experiencia en el manejo clínico e inmunohematológico de gestantes con anti-Kl. Materiales y métodos: Estudio de 30 gestantes con anti-Kl, controladas entre 2005-2012, sobre un N = 48.550 embarazadas. Se estudiaron: compromiso fetal. necesidad de terapéutica intragestacional y posparto, semanas de gestación en el momento del diagnóstico, estado perinatal y complicaciones de las terapéuticas. Además, ABO-Rh, fenotipo materno Rh/Kell, detección e identificación de Acs, título, score, fenotipo Rh/K paterno, seguimiento con ultrasonido para detectar signos de anemia, y desde 2008 control del Pico Sistólico Máximo en arteria cerebral media (PSM-ACM). Resultados: Del total de madres estudiadas, 30 (0,06%) tenían anti-Kl (solo o con anti-D+C, anti-D o anti-Klpa).Títulos de anti-Kl: entre 8 y 8192. De esas solamente 9 (30%) con antecedentes transfusionales. Todos los fetos nacieron vivos. En la mayoría, la inmunización fue leve, sin repercusión en el feto, salvo cuando asociado con Anti-D (quien requirió 5 transfusiones intraútero -TIU- y gammaglobulina intravenosa -lgIV ­entre semana 14 y 32). Todos los recién nacidos (RN) tuvieron peso y apgar adecuados. Hubieron 2 nacimientos prematuros (36 y 34 sem), 1 por diabetes + hipertensión y el otro con Enfermedad Hemolítica Perinatal (EHP) por anti-D+C. Los PSM-ACM fueron adecuados para cada edad gestacional, y nunca superaron el 1,49 múltiplo de la mediana. excepto en 1 paciente con Anti-D...

Introduction: The main cause of fetal anemia is caused by anti-D antibodies (Abs). Anti-K1 immunization is infrequent but can lead to asevere episode of fetal anemia. Its relative incidence has increased in the last few years due to increasing blood transfusions and diminishing anti-D immunization. We hereby present 30 cases of pregnant women with anti-K1. Objective: To show our experience in handling pregnant women with anti-K1.Materials and methods: Retrospective study of 30 pregnant women with anti-K1, under surveillance in the period 2005-2012, N= 48,550 women. Study outcome measures: fetal condition, peripartum (intravenous glob­ulin [IVlg], intrauterine transfusion [IUT]) therapy. Other measures: gestational age at the moment of diagnostic, perinatal status (abortion, fetal death, regular delivery, C­section or need for induction) and therapy complications. Immunohematology tests: ABO-Rh, maternal Rh/Kell phenotype, Ab screening and identification, titer, score,paternal Rh/K phenotype. In all cases of a mother with anti-K1 and a K+ father, confirmed or suspected, a detailed ultrasound follow-up was carried out to detect signs of ane­mia and, from 2008 onwards, a control of middle cerebral artery peak systolic velocity (MCA-PSV). Immunization was rated as low when no antepartum treatment was necessary, and as severe when such treatment was needed. Results: Out of all the studied women, 30 (0,06%) presented anti-K1 (alone or accompanied by anti-D+C, anti-D or anti-K1 pa). Anti-K1 titers: 8 to 8192. Only 9 (30%) patients informed previous transfusional events. AII fetuses were born alive. ln most pregnancies immunization was low, without any effects on the fetus, except for a case related to Anti-D (requiring 5 IUT and Ivlg between weeks 14 and 32). AII newborns (NB) had adequate weight and apgar readings...

An easy and efficient strategy for KEL genotyping in a multiethnic population

BACKGROUND: The Kell blood group system expresses high and low frequency antigens with the most important in relation to transfusion including the antithetic KEL1 and KEL2; KEL3 and KEL4; KEL6 and KEL7 antigens. Kell is a clinically relevant system, as it is highly immunogenic and anti-KEL antibodies are associated with hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. Although required in some situations, Kell antigen phenotyping is restricted due to technical limitations. In these cases, molecular approaches maybe a solution. This study proposes three polymerase chain reaction genotyping protocols to analyze the single nucleotide polymorphisms responsible for six Kell antithetic antigens expressed in a Brazilian population. METHODS: DNA was extracted from 800 blood donor samples and three polymerase chain reaction-restriction fragment length polymorphism protocols were used to genotype the KEL*1/KEL*2, KEL*3/KEL*4 and KEL*6/KEL*7 alleles. KEL*3/KEL*4 and KEL*6/KEL*7 genotyping was standardized using the NlaIII and MnlI restriction enzymes and validated using sequencing. KEL*1/KEL*2 genotyping was performed using a previously reported assay. RESULTS: KEL genotyping was successfully implemented in the service; the following distribution of KEL alleles was obtained for a population from southeastern Brazil: KEL*1 (2.2%), KEL*2 (97.8%), KEL*3 (0.69%), KEL*4 (99.31%), KEL*6 (2.69%) and KEL*7 (97.31%). Additionally, two individuals with rare genotypes, KEL*1/KEL*1 and KEL*3/KEL*3, were identified. CONCLUSION: KEL allele genotyping using these methods proved to be reliable and applicable to predict Kell antigen expressions in a Brazilian cohort. This easy and efficient strategy can be employed to provide safer transfusions and to help in rare donor screening.

Distribution of erythrocyte phenotypic groups in women with benign tumors of the uterus in Adjara Oncology Centre.

ABO blood groups antigens have biological and clinical significance. The ABO blood groups antigens has been associated with many diseases, though the explanation between ABO blood groups and disease is still unclear. The aim of this study is to investigate the presence of a possible association between benign tumors of the utesus with blood ABO, RhD, Kell and MN groups in women in reproductive periods. In diseased population (60 subject) was investigated for Erythrocyte phenotypic groups antigens. Immunoserological methods have been used to identify the antigens. The obtained results were statistically processed. High frequencies of A (43,3±3,2%), D(91,6±3,5%) and Kell (+) (26.66±5.7 %) antigens were found in diseased of benign tumors of uterus comparison with donor. The researches shows, that is increased risk of disease development in carriers of these phenotypes. In summary, according our research we've thought, that blood groups may be a marker for bening tomors of the uterus. Based on these data, these could be used as prognostic factor for bening tomors of the uterus. The study of Erythrocyte group antigens in diseased we may to identify "high risk" individuals, that help to find ways, which help to control of disease.

Identification, immunomodulatory activity, and immunogenicity of the major helper T-cell epitope on the K blood group antigen.

The K blood group remains an important target in hemolytic disease of the newborn (HDN), with no immune prophylaxis available. The aim was to characterize the Th response to K as a key step in designing specific immunotherapy and understanding the immunogenicity of the Ag. PBMCs from K-negative women who had anti-K Abs after incompatible pregnancy, and PBMCs from unimmunized controls, were screened for proliferative responses to peptide panels spanning the K or k single amino acid polymorphism. A dominant K peptide with the polymorphism at the C terminus elicited proliferation in 90% of alloimmunized women, and it was confirmed that responding cells expressed helper CD3(+)CD4(+) and "memory" CD45RO(+) phenotypes, and were MHC class II restricted. A relatively high prevalence of background peptide responses independent of alloimmunization may contribute to K immunogenicity. First, cross-reactive environmental Ag(s) pre-prime Kell-reactive Th cells, and, second, the K substitution disrupts an N-glycosylation motif, allowing the exposed amino acid chain to stimulate a Th repertoire that is unconstrained by self-tolerance in K-negative individuals. The dominant K peptide was effective in inducing linked suppression in HLA-transgenic mice and can now be taken forward for immunotherapy to prevent HDN because of anti-K responses.