Effect of phenotypes of Duffy blood group on chemokine storage and chemokine scavenging function of erythrocytes / 中国输血杂志

【Objective】 To investigate the effect of phenotypes of Duffy blood group on chemokine storage and chemokine scavenging function of erythrocytes. 【Methods】 Twenty-four erythrocyte samples were collected and tested Duffy blood phenotype using the anti-human globulin method, and erythrocyte CCL2, CCL5, CXCL8, and CCL11 content and their chemokine scavenging function using ELISA. The expression of Duffy antigens on erythrocytes was detected using a flow analyzer. 【Results】 The difference in CCL2 content(41.1±14.7 pg/mL vs 63.1±20.8 pg/mL)of erythrocyte lysate between Fy(a+b-) and Fy(a+b+) phenotype was statistically significant (P0.05).The difference in the scavenging function of CCL2(1471±202.1 pg/mL vs 1860±267.5 pg/mL)and CCL5 (848.5±461.7 pg/mL vs 1797±546.1pg/mL) between Fy(a+b-) and Fy(a+b+) phenotype were statistically significant (P0.05).The difference in Duffy antigen expression (mean fluorescent intensity:105.3±20.45 vs 111.9±18.30)on erythrocytes between Fy(a+b-) and Fy(a+b+) phenotype was not statistically significant (P>0.05). 【Conclusion】 The Fy(a+b+) and Fy(a+b-) phenotypes of the Duffy blood group can affect the chemokine storage and scavenging function of erythrocytes. Fy(a+b+) phenotypes are able to store more chemokines and have a stronger chemokine scavenging function than Fy(a+b-) phenotypes.

Serological and Molecular Study of the Duffy Blood Group among Malarial Endemic Region Residents in Brazil

ABSTRACT Background: The atypical chemokine receptor 1 (ACKR1) gene encodes the Duffy blood group antigens in two allelic forms: FY*A (FY*01) and FY*B (FY*02), which define the Fy(a+b-), Fy(a-b+), and Fy(a+b+) phenotypes. FY*BES (FY*02N.01) is a single T to C substitution at nucleotide -67 that prevents the FY*B from being expressed in red blood cells (RBCs). Methods: We evaluated 250 residents from a Brazilian malarial endemic region (RsMR). All individuals were phenotyped for Fya and Fyb antigens and genotyped for FY*A, FY*B, FY*B SE , and FY*B weak alleles. Results: Among the 250 individuals, 209 (83.6%) reported previous malaria infection, and 41 (16.4%) did not. The Fy(a+b+) phenotype was present in 97/250 (38.8%), while the Fy(a-b-) was present in 7/250 (2.8%). The FY*A/FY*B was found in 130/250 (52%) and the FY*A/FY*A in 45/250 (18%). The c.1-67>TC was present, in homozygosity, in 11/250 (4.4%). Among 34 individuals with the Fy(a+b-) and FYA*/FYB* mutations, 4/34 (11.8%) had homozygosity for the c.1-67T>C. One individual presented the Fy(a+b-), FY*A/FY*B, and c.1-67T>C in homozygosis, whereas the other presented the Fy(a+b-), FY*A/FY*A, and c.1-67T>C in heterozygosis. Conclusions: We reported a low prevalence of the Fy(a-b-) in persons who had previously been infected with Plasmodium vivax (67.5%). We observed that 102/141 (72.3%) individuals expressing the Fyb antigen had a P. vivax infection, indicating the importance of the Fyb antigen, silenced by a c.1-67T>C mutation in homozygosis, in preventing the P. vivax infection. We showed that the c.1-67T>C mutation in the FY*A did not silence the FY*A expression on RBCs.

Reacción hemolítica transfusional tardía en un paciente con anemia de células falciformes: reporte de un caso / Delayed hemolytic reaction to transfusion in sickle cell anemia: report of one case

Sickle cell anemia was a rare disease in Chile, especially in adults, however the recent immigration wave from Haiti is changing this scenario. We report a 29 year old black female from Haiti with a non-disclosed history of sickle cell anemia. She was transfused with two units of red blood cells, found unconscious and with jaundice five days later and admitted to the hospital. On admission she had a hemoglobin of 3.3 g/dL, a total bilirubin of 5.08 mg/dL, a LDH of 1,306 Ui/L. She was transfused again, worsening her condition. An alloimmunization and delayed hemolytic reaction was suspected. A direct Coombs test was positive. She was treated with steroids and her serum hemoglobin rose progressively.

A Case of Sickle Cell Anemia with a Lack of High Frequency Red Blood Cell Antigen / 대한수혈학회지

Patients with sickle cell anemia are chronically transfused. Therefore, it is important to prevent the alloimmunization of RBC antigens. The authors identified a high frequency antigen-negative blood group in patients with sickle cell anemia. As the number of foreigners residing in Korea is increasing, it is necessary to know what to consider when transfusing blood to sickle cell anemia patients. Patients with sickle cell anemia should be informed of the exact blood group type using extended RBC typing to confirm the ABO, Rh, Kell, and Duffy blood types at diagnosis or before the first blood transfusion. Extended matched blood transfusion can reduce the risk of alloimmunization of RBC antigens.

Case report and literature review of neonatal hemolysis induced by anti-E and anti-Ec combined with anti-Fyb / 天津医药

Hemolytic diseases of newborn (HDN) can cause miscarriage, premature birth, fetal edema, fetal intrauterine anemia and even fetal death in early pregnancy. Neonatus with HDN can have jaundice, anemia, hepatosplenomegaly, edema and nuclear jaundice sequelae. This article reviewed the diagnosis and treatment of two patients with HDN caused by anti-E and anti-Ec combined with anti-Fyb, and reviewed the relevant literature on the epidemilogy, the diagnosis and treatment of HDN in order to improve the understanding of the disease.

Case of Acute Hemolytic Transfusion Reaction due to Anti-Fy(a) Alloantibody in a Patient with Autoimmune Hemolytic Anemia / 대한수혈학회지

A 72-year-old man with general weakness visited the outpatient clinic of the hematology department. The patient had been treated under the diagnosis of autoimmune hemolytic anemia for 2 years. His hemoglobin level at the time of the visit was 6.3 g/dL, and a blood transfusion was requested to treat his anemia. The patient's blood type was A, RhD positive. Antibody screening and identification test showed agglutination in all reagent cells with a positive reaction to autologous red blood cells (RBCs). He had a prior transfusion history with three least incompatible RBCs. The patient returned home after receiving one unit of leukoreduced filtered RBC, which was the least incompatible blood in the crossmatching test. After approximately five hours, however, fever, chills, dyspnea, abdominal pain, and hematuria appeared and the patient returned to the emergency room next day after the transfusion. The anti-Fy(a) antibody, which was masked by the autoantibody, was identified after autoadsorption using polyethylene glycol. He was diagnosed with an acute hemolytic transfusion reaction due to anti-Fy(a) that had not been detected before the transfusion. In this setting, it is necessary to consider the identification of coexisting alloantibodies in patients with autoantibodies and to become more familiar with the method of autoantibody adsorption.

Clinical analysis of seven cases of rare hemolytic disease of the newborn / 中华儿科杂志

Objective@#To summarize the clinical features of 7 rare cases of hemolytic disease of newborn (HDN), and to improve the understanding of rare HDN.@*Methods@#Data of clinical information, laboratory findings, treatments and outcomes were collected and analyzed for four cases with HDN due to anti-M, two cases due to anti-Kidd, and one case due to anti-Duffy. All of them were admitted to the Department of Neonatology, Beijing Children's Hospital Affiliated to Capital Medial University from July 2007 to June 2017.@*Results@#Among the four MN hemolytic babies, two were males and two were females. Jaundice was found in three cases. Two cases had hyperbilirubinemia, one of them had severe hyperbilirubinemia. All the four cases developed anemia, including severe anemia in three cases. Two cases of Kidd hemolytic disease and 1 case of Duffy hemolytic disease had jaundice and anemia, but did not reach the level of severe hyperbilirubinemia and severe anemia. MN hemolytic disease babies got negative results in direct antiglobulin test, whereas the Kidd and Duffy hemolytic disease babies had positive findings in direct antiglobulin test. None of the babies had blood transfusion, and they were discharged from the hospital.@*Conclusions@#Without maternal and fetal blood group incompatibility (ABO or Rh blood-group system), for early onset of jaundice, severe jaundice or anemia, antiglobulin test to mother and child earlier should be administered, and MN, Kidd, Duffy and other rare hemolytic disease of the newborn should be pay attention to.

Survey and study on FYES and FYX alleles of Duffy blood group in Nanjing Han population / 国际检验医学杂志

Objective To investigate the FYES and FYX allele expression situation of Duffy blood group in Han population of Nanjing area.Methods The genomic DNA was randomly extracted from peripheral EDTA-K2 anticoagulation blood samples in 200 voluntary blood donors and Duffy blood group FYA and FYB allele typing was performed by PCR-SSP.The EYES and FYX allele sequence charateristics of Duffy blood group were analyzed by adopting Sanger double deoxygenation gene sequencing method.Results The PCR genotyping results were consistent with the sequencing results.Among 200 samples,180 cases were FYA/FYA and 20 cases were FYA/FYB;the sequencing results showed that FYES and FYX allele expression was not been found in 200 samples.Conclusion The expression frequencies of FYES and FYX alleles are extremely low in Han population of Nanjing area,which has significant difference compared with other races.

Duffy Blood Group Genotyping in Thai Blood Donors

BACKGROUND: Duffy (FY) blood group genotyping is important in transfusion medicine because Duffy alloantibodies are associated with delayed hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. In this study, FY allele frequencies in Thai blood donors were determined by in-house PCR with sequence-specific primers (PCR-SSP), and the probability of obtaining compatible blood for alloimmunized patients was assessed. METHODS: Five hundred blood samples from Thai blood donors of the National Blood Centre, Thai Red Cross Society, were included. Only 200 samples were tested with anti-Fy(a) and anti-Fy(b) using the gel technique. All 500 samples and four samples from a Guinea family with the Fy(a-b-) phenotype were genotyped by using PCR-SSP. Additionally, the probability of obtaining antigen-negative red blood cells (RBCs) for alloimmunized patients was calculated according to the estimated FY allele frequencies. RESULTS: The FY phenotyping and genotyping results were in 100% concordance. The allele frequencies of FY*A and FY*B in 500 central Thais were 0.962 (962/1,000) and 0.038 (38/1,000), respectively. Although the Fy(a-b-) phenotype was not observed in this study, FY*B(ES)/FY*B(ES) was identified by PCR-SSP in the Guinea family and was confirmed by DNA sequencing. CONCLUSIONS: Our results confirm the high frequency of the FY*A allele in the Thai population, similar to that of Asian populations. At least 500 Thai blood donors are needed to obtain two units of antigen-negative RBCs for the Fy(a-b+) phenotype.

Duffy blood group genotypes among malaria Plasmodium vivax patients of Baoulch population in Southeastern Iran

OBJECTIVE@#To determine the distribution of Duffy blood group genotypes in Balouch population as a major ethnic group that living in a sub-tropical area in south East of Iran.@*METHODS@#In this study, the Duffy blood group FY phenotypes were determined using indirect anti-globulin technique and also genotype by PCR-RFLP in 160 vivax malaria patients and 160 control individuals.@*RESULTS@#The results showed that the most common Duffy genotype was FYA/FYB (46.6%) followed by FYA/FYA (15.3%), FYA/FYO (14.4%), FYB/FYO (11.9%), FYB/FYB (10%) and FYO/FYO (1.9%). In case individuals, frequency of FYA, FYB and FYO alleles were 0.471, 0.431 and 0.097, respectively compaired to 0.444, 0.353 and 0.203, respectively in control (non-infected) group.@*CONCLUSIONS@#This data provide evidence that individuals with the FYA/FYB genotype have higher susceptibility to malaria and there are significant associations between Duffy blood group variants and susceptibility or resistance to vivax malaria.

Expresión del fenotipo Duffy negativo en mujeres afrodescendientes y su relación con la preeclampsia / Expression of the Duffy negative phenotype in women of African descent and their relation to pre-eclampsia

La preeclampsia (PE) es una complicación del embarazo que trae consigo algunas consecuencias negativas para la madre y el feto: en la madre provoca principalmente hipertensión y proteinuria, mientras que en el feto puede presentarse trombocitopenia, alteración en el desarrollo del sistema nervioso central y circulatorio, y restricción del crecimiento intrauterino, lo cual se considera el factor de riesgo principal de muerte fetal en nacimientos producto de una PE severa. En la preeclampsia se presenta una disfunción endotelial relacionada con placentación anormal, estado de estrés oxidativo y proceso inflamatorio sistémico, que lleva a la activación de neutrófilos y monocitos. Se ha considerado a la interleucina-8 (IL-8) como un posible candidato desencadenante por ser quimioatrayente y activador de leucocitos; en la circulación sanguínea, la IL-8 se une a un receptor de quimiocina multiespecífico de alta afinidad denominado DARC, que es idéntico al antígeno del grupo sanguíneo Duffy. Este receptor regula los niveles plasmáticos de IL-8, uniéndose a esta quimiocina, pero cuando hay una mutación en la región promotora del gen se altera la expresión de DARC, lo que conlleva a que la IL-8 de los factores genéticos involucrados en la activación de los neutrófilos y de los monocitos, y por ende, en la disfunción endotelial presentada durante este síndrome hipertensivo, especialmente en la población afrodescendiente.

Preeclampsia (PE) is a complication of pregnancy that brings some negative consequences for both mother and fetus. It specially causes hypertension and proteinuria in mothers; while in fetuses it causes thrombocytopenia, development alterations of the central nervous and circulatory system; also intrauterine growth restriction may occur. This last factor is regarded as the main risk factor for fetal death in births as a result of severe PE. There is endothelial dysfunction in preeclampsia related to abnormal placentation, state of oxidative stress and systemic inflammatory process that leads to the activation of neutrophils and monocytes. Interleukin-8 (IL-8) is considered as a possible trigger candidate, since this chemokine is a chemoattractant and leukocyte activator. In the bloodstream, interleukin-8 binds to a high affinity multispecific-chemokine receptor called DARC, which is identical to the Duffy blood group antigen. This receptor regulates plasma levels of IL-8 by binding to chemokine. But, when there is a mutation in the gene promoter region, DARC expression is altered, and IL-8 inefficiently binds to receptor. This mutation results in Duffy negative phenotype, which is present in most of African descendants. This literature review is intended to address the role of IL-8 as neutrophil chemo-attractant, the importance of Duffy blood system and the possible association between ethnicity and preeclampsia.

Characteristics of Duffy Blood Group Antigens and Their Global Distribution / 대한수혈학회지

The Duffy antigen was discovered in 1950, in a multiply transfused hemophiliac. Important progress has since been made in understanding the Duffy blood group system and its complexity. The Duffy blood group antigen (gp-Fy) is present primarily in erythrocytes, and also in endothelial cells of capillary and postcapillary venules, Purkinje cells of cerebellum, kidney, and pulmonary alveoli. The gp-Fy serves not only as a blood group antigen, but also as a receptor for chemokines, and as a receptor for Plasmodium vivax malaria parasites. The Duffy antigen is encoded by the DARC gene, its approved name is Duffy blood group chemokine receptor. Investigation of the DARC gene can help us in understanding the relationship of infectious disease to race or population. In addition, the allelic frequency of DARC varies according to the geographic area, which appears to reflect the history that mankind had adapted to environments and diseases, emigrating. As a result, further study of Duffy antigens can provide us with an integral and sound understanding of the human race.

High-Resolution Melting Analysis for Genotyping Duffy Blood Group Antigens / 대한수혈학회지

BACKGROUND: Accurate typing of Duffy blood group is important because anti-Duffy antibodies cause hemolytic transfusion reaction and hemolytic disease of the newborn. The aim of this study was to evaluate a new genotyping method using high resolution melting (HRM) analysis, a rapid and inexpensive approach for high-throughput Duffy genotyping. METHODS: A total of 20 unrelated Korean blood samples were obtained and an African-black sample was used for GATA control. Phenotyping was performed by hemagglutination (DiaMed AG, Switzerland). GATA and FYA/B PCR products were obtained by PCR-restriction fragment length polymorphism (RFLP) using Taq DNA polymerase (Promega, WI) and enzymes BanI and StyI (New England Biolab, UK). For HRM, PCR amplification was performed using LightCycler 480 ResoLight Dye (Roche, USA) and Lightcycer 480 (Roche, USA). RESULTS: Phenotyping and genotyping data using PCR-RFLP and HRM analysis were compared. Different types of HRM curves were obtained according to genotypes, FYA/FYA, FYB/FYB, and FYA/FYB, and to GATA mutations, homozygote FYB-33T (T/T), heterozygote FYB-33T/33C (T/C), and homozygote FYB-33C (C/C). Phenotypes 18 Fy(a+b-), 1 Fy(a+b+), 1 Fy(a-b+), and 1 Fy(a-b-) showed complete concordance with genotyping methods. Fy(a-b-) sample was found to be a FYB-33C homozygote by both genotyping methods. CONCLUSION: Phenotyping and genotyping showed concordant results and both genotyping methods using PCR-RFLP and HRM analysis showed good agreement in finding mutation in GATA and FY gene coding regions. HRM analysis is suitable and reliable for high-throughput screening for Duffy genotyping.

Actividad del cortisol plasmático en ratas en condiciones de estrés crónico suplementadas con resveratrol / Plasma cortisol activity in rats under conditions of chronic stress supplemented with resveratrol

Objective: Determine the activity of cortisol in rats treated with exogenous adrenocorticotropic hormone (ACTH) and a resveratrol supplement. Methodology:Forty-eight adult male rats and 16 adult female rats (Rattus norvegicus) three months old with a body weight of 200 to 250g and 300 to 350g for both male and female were used and kept in controlled environmental conditions, temperature of 20±2°C and light-dark cycles of 14 and 10 hours. They were fed with balanced food and had free access to water. The rats were randomly divided into four groups: group 1, was treated with 5 µg/kg of ACTH i.p. every twelve hours; group 2, received the same treatment with ACTH plus a grape extract supplementation of 40 mg/kg; group 3, only received grape extract and group 4,served as control and only received saline solution (0.9%) i.p. The experimental was designed as a 2×2 factorial with two ACTH levels and two extract grape levels. Results:Significant differences were not found in cortisol concentrations for day, gender or treatment effects (0.75ug/dL ± 0.11; p<0.001).

Objetivo: Determinar la actividad de cortisol en ratas tratadas con hormona adrecorticotropa (ACTH) exógena y un suplemento de resveratrol.Metodología:Se utilizaron 48 ratas hembras adultas y 16machos de la cepa wistar (Rattus norvegicus) de tres meses de edad y con un peso corporal de 200-250g y 300-350 g, para hembras y machos, respectivamente, que permanecieron en condiciones ambientales controladas, temperatura 20±2°C de ciclos de luz-oscuridad de 14 y 10 horas, respectivamente.Se les proporcionó alimento balanceado con libre acceso a agua. Las ratas fueron divididas en cuatro grupos al azarasí: grupo 1, fue tratado con 5 µg/kg de ACTH i.p. cada 12 horas; grupo 2, recibió el mismo tratamiento con ACTH además de una suplementación oral de 40 mg/kg de extracto deshidratado de uva (resveratrol); grupo 3, solo recibió extracto de uva y el grupo 4,recibió solución salina y sirvió como control y (0,9%) i.p. y oral. El diseño experimental fue en factorial 2×2, con dos niveles de ACTH y dos niveles de polifenol. Resultados: No se encontraron diferencias significativas del cortisol sanguíneo, con respecto al día y sexo, entre los tratamientos (0,75ug/dL ± 0,11; p<0,001). Conclusión: Los resultados sugieren que el estrés crónico y el consumo de resveratrol no alteran directamente los niveles plasmáticos de cortisol, en ratas estresadas y no estresadas. De la misma manera que, posiblemente la dosis utilizada de ACTH no produjo estimulación de la glándula suprarrenal en las ratas.

Duffy blood group system and the malaria adaptation process in humans

Malaria is an acute infectious disease caused by the protozoa of the genus Plasmodium. The antigens of the Duffy Blood Group System, in addition to incompatibilities in transfusions and hemolytic disease of the newborn, are of great interest in medicine due to their association with the invasion of red blood cells by the parasite Plasmodium vivax. For invasions to occur an interaction between the parasites and antigens of the Duffy Blood Group System is necessary. In Caucasians six antigens are produced by the Duffy locus (Fya, Fyb, F3, F4, F5 and F6). It has been observed that Fy(a-b-) individuals are resistant to Plasmodium knowlesi and P. vivax infection, because the invasion requires at least one of these antigens. The P. vivax Duffy Binding Protein (PvDBP) is functionally important in the invasion process of these parasites in Duffy / DARC positive humans. The proteins or fractions may be considered, therefore, an important and potential inoculum to be used in immunization against malaria.

Chagas' disease and Duffy antigen/receptor for chemokine (DARC): a mini-review

Duffy gene (FY) codifies the transmembrane glycoprotein Duffy (gp-Fy) of 35 to 43 kDa which is moderately immunogenic. This glycoprotein is polymorphic, and constitutes the antigens of the Duffy histo-blood system which were designated receptors for chemokines and denominated DARC (Duffy antigen/receptor for chemokine). This receptor has an important role in the regulation of chemokine levels in the circulation, as it binds and adsorbs them on the surface of red cells as a reservoir. It plays a "sink" role, which can contribute to homeostasis by removing inflammatory chemokines from circulation as well as maintaining them in plasmatic levels. Chronic Chagas' cardiopathy (CCC) is the most frequent form of the disease. It is an inflammatory disease, in which infiltrated inflammatory cells play an important role in the development and progress of the infection. High chemokine levels in the plasma have been associated with the disease severity in patients with heart failure. In this context, the profile of DARC expression could play an important function as a receptor for chemokines in Chagas' disease, in patients with CCC, as it can modulate damage from this inflammatory disease.

Duffy blood group genotypes among African-Brazilian communities of the Amazon region

Duffy blood group genotype was studied in 95 unrelated subjects from four African-Brazilian communities of the Amazon region: Trombetas, Pitimandeua, Curiaú, and Mazagão Velho. Genotyping was performed using an allele-specific primer polymerase chain reaction technique for determining the three major alleles at FY blood group, and as expected, FY*O allele was the most common one, with frequencies ranging from 56.4% in Mazagão Velho to 72.2% in Pitimandeua, whereas the FY*O/FY*O genotype was found with frequencies between 32.3% in Mazagão Velho and 58.8% in Curiaú. Genotype and allele distributions in the four Amazonian communities are consistent with a predominantly African origin with some degree of local differentiation and admixture with people of Caucasian ancestry and/or Amerindians. These results reveal that the impact of the FY*O/FY*O genotype on the transmission and endemicity of the vivax malaria deserves to be investigated in full detail in an attempt to identify the contribution of host biological factors and explain the non-homogeneous prevalence of malaria in the region expressed by its different levels of exposure

Polymorphism of Duffy blood group phenotypes and breast cancer in Chinese female breast disease patients of Han population / 中国癌症杂志

Background and purpose:Duffy blood group(DBG)system contains genotype system and phenotype system.DBG phenotype system is embodied by the protein carrying blood group antigens on the surface of red blood cells.Epidemiological evidence has shown that different races had definitely different DBG phenotype disuribution and there is a variation of morbidity and mortality of breast cancer among different race populations.Therefore,this study was to investigate whether DBG phenotype affects breast cancer occurrence and malignancy.Methods:We investigated DBG phenotypes of 253 female cases with breast diseases who were consecutively hospitalized in the Shanghai Cancer Hospital and analysis was done on its relationship with clinical pathological diagnosis.DBG phenotypes were examined by indirect antiglobulin-test with anti-Fya and anti-Fyb reagents,and were classified into Fya+Fyb-,Fya-Fyb+,Fya+Fyb+,Fya-Fyb-according agglutination.Results:Neither DBG phenotypes distribution difference existed in breast disease patients nor in breast cancer patients as observed in the general Chinese Han population.Fya-Fyb-and Fya-Fyb+ demonstrated more susceptibility to breast cancer than Fya+Fyb-and Fya+Fyb+,but there was no statistical significant difference.Fya-group(57.14%)had more malignant incidence than that of Fya+ group(39.02%),but there was also no statistical significance(P=0.28).No significant differences have been observed in ER,PR,Her-2 status and P53,PCNA,PS2,nm23,P450 status between every DBG phenotypes,nor in tumor grades in various DBG phenotypes.More patients were involved in axillary lymph nodes metastasis in Fya-than that in Fya+ group and reached statistical significance(100% and 39.13% respectively,P

The mutation G298A®Ala100Thr on th coding sequence of the Duffy antigen/chemokine receptor gene in non-caucasian Brazilians

Ala100Thr has been suggested to be a Caucasian genetic marker on the FY*B allele. As the Brazilian population has arisen from miscegenation among Portuguese, Africans, and Indians, this mutation could possibly be found in Euro- and Afro-Brazilians, or in Brazilian Indians. Fifty-three related individuals and a random sample of 100 subjects from the Brazilian population were investigated using the polymerase chain reaction and four restriction fragment length polymorphisms. Confirming the working hypothesis, among the related individuals three Afro-Brazilians (two of them a mother and daughter) and a woman of Amerindian descent had the Ala100Thr mutation on the FY*B allele. Five non-related Euro-Brazilians also carried the mutation. All nine individuals presented the Fy(a-b+) phenotype. We conclude that the Ala100Thr mutation can occur in populations other than Caucasians and that this mutation does not affect Duffy expression on red blood cells. Gene frequencies for this allele in the non-related individuals were in agreement with those of other populations. The Duffy frequencies of two Amerindian tribes were also investigated.

Alleles for Associated with Fy(a), Fy(b), Fy(x) and Fy Antigens in a Korean Population / 대한수혈학회지

BACKGROUND: In the Duffy blood group system (Fy(a), Fy(b), Fy(x), and Fy antigens), Fy(x) antigen is associated with weak Fy(b) while Fy antigen means the null phenotype Fy (a-b-). Fyx antigen and Fy antigen result from the polymorphisms of Fy125 allele. This report assessed the allele frequency and genotype frequency of Fy(a), Fy(b), Fy(x), and Fy antigens in Koreans. METHODS: We performed a study of the followings on 253 visitors to the health promotion center of Seoul National University Bundang Hospital: PCR-RFLP and PCR-SSP for the detection of Duffy 125G > A and -33T > C; PCR-SSP for the detection of Duffy 265C > T and 298G > A. RESULTS: The results of PCR-RFLP and PCR-SSP were consistent with each other in a total of 253 subjects. Allele frequency was as follows: Fy 92.3%, Fy(125) 6.1%, and fy(125/265) 1.6%. The fy(125/265) allele was newly observed. Fy(125/298), fy(125/265/298), and fy(-33/125) alleles were not detected in Koreans. The distribution of Duffy phenotypes in Koreans was as follows: Fy (a+b-) 88.1%, Fy (a-b+) 0.4%, Fy (a+b+) 11.5%, and Fy (a-b-) 0.0%. Fy (a+) was 99.6% and Fy (b+) was 11.9%. CONCLUSION: In our study for Duffy polymorphisms, the frequency of Fy allele was very high. The frequency was similar to those of other Asian populations, but different from those of Caucasians. The fy(125/265) allele, which was associated with Fy(x) antigen, was newly detected in Koreans.