Red Cell Blood Group Antigens Research Articles

Detection of red cell alloantibodies in thalassaemia patients

Background: β-thalassaemia patients receive regular blood transfusion to thrive. Due to antigen disparity between the blood donors and these patients they develop red cell alloantibodies due to alloimmunization. The objective of this study is to predict the frequency of red cell alloimmunization amongst β-thalassaemia major patients receiving regular blood transfusion.Methods: This study including 106 patients with β-thalassaemia was conducted in the department of Transfusion Medicine, S. C. B. Medical College, Cuttack for a period of 12 months. Alloantibodies to different red cell blood group antigens in multi-transfused thalassaemia patients were detected using the glass bead technology for blood group serology in the present study.Results: Out of 106 β-thalassaemia major patients included in the study, 7.5% of patients developed alloantibodies, all being clinically significant. The alloantibodies were anti-E, anti c, anti e and anti-D. The rate of incidence of these alloantibodies was 3.8%, 1.9%, 0.9% and 0.9% respectively. There was a significant association between alloantibody formation with number of transfused packed red cells (Mann-Whitney Test: p value = 0.035) and age at first transfusion (p value = 0.001). The factors having no association with alloimmunization to red cell antigens are age and gender.Conclusions: Alloimmunization to various erythrocyte blood group antigens is a common problem in multi-transfused β-thalassaemia patients. There is an association between number of transfused packed red cells and age at first transfusion with alloantibody formation in the study.

Prevalence of Red Cell Blood Group Antigens Among Egyptian Population in Comparison with Other Ethnic Groups

Prevalence of Red Cell Blood Group Antigens Among Egyptian Population in Comparison with Other Ethnic Groups

Basic aspects, application and platforms currently available for molecular blood grouping of donor and patient population

The majority of allelic variants conferring red cell blood group antigens are attributable to single nucleotide polymorphisms, which are immensely amenable to routine genotyping methods such as PCR‐RFLP, SSP, SSO and fluorescent‐based real‐time PCR assays. These techniques are feasible in a low‐ to medium‐throughput setting. Multiplexing and use of solid surfaces or beads for probe capture have further improved the throughput and turnaround time allowing multiple alleles to be interrogated simultaneously. Novel approaches, as in the use of MALDI‐TOF mass spectrometry, appear as an attractive option for accurate, cost‐effective, high‐throughput SNP genotyping within major blood centres. Massively parallel targeted sequencing is likely the next step in the evolution of RBC genotyping. In the hospital setting, genotyping is unlikely to supplant serological typing but would rather be complementary to it. Scenarios where it would play an important role would be in the transfusion management of transfusion dependant patients such as in sickle cell anaemia or in situations where RBC phenotyping cannot be reliably undertaken as in auto‐immune haemolytic anaemia and haemolytic disease of foetus and newborn. Genotyping would also be useful where anti‐sera are not readily available or are of weak potency. Molecular typing is likely to, however, show its greatest potential in donor genotyping to establish pools of fully typed donors as well as identify donors with rare blood groups. Such an exercise will facilitate prompt and efficient delivery of best‐matched blood for patients.

Prenatal Fetal DNA Testing for Predicting HDFN, FNAIT, and RhIG Candidacy

Red cell blood group antigen and platelet antigen incompatibility between a pregnant women and her fetus can result in maternal alloimmunisation and, consequently, hemolytic disease of the fetus and newborn (HDFN) and fetal neonatal alloimmune thrombocytopenia (FNAIT), respectively. For a long time, immunization against D-antigen has been the major cause of HDFN, but postnatal immune-prophylaxis and more recently antenatal immunoprophylaxis, has successfully decreased its incidence. The majority of severe FNAIT cases are caused by antibodies against HPA-1a, and a comparable immunoprophylaxis program is presently investigated. Postnatal immunoprophylaxis is traditionally given based on the fetal blood group determined on cord blood, since only 60 percent of the newborns of a D-negative mother are D-positive. But as long as the fetal blood group is not known, antenatal prophylaxis is administered to all D-negative women. Also in alloimmunised pregnant women, knowledge of the fetal antigen status is beneficial to tailor pregnancy management. In case of red cell alloantibodies, the antibody titers have to be followed during pregnancy and the fetus is careful monitored to recognize fetuses needing intrauterine blood transfusions. In many countries, pregnant women with anti-HPA-1a alloantibodies are treated with intravenous IgG during the last trimester of pregnancy to prevent intracranial hemorrhages. Traditionally, fetal blood group genotyping has been performed through amniocentesis. This invasive procedure carries a small risk of miscarriage (especially in FNAIT cases) and could potentially enhance maternal sensitization. The discovery of cell-free fetal DNA in the blood of pregnant women in 1997 presented a noninvasive, and thus safe, method to determine the fetal blood group genotype. Cell-free fetal DNA is released from trophoblastic cells undergoing apoptosis. Within the maternal circulation, cell-free fetal DNA is present among an overwhelming background of maternal cell-free DNA, predominately of hematopoietic origin. It can be detected at as early as five weeks of gestation, and gradually increases during pregnancy, from 10 genome equivalents (GE) per ml to around 300 GE late in pregnancy, although quantities vary between pregnancies. After birth, cell-free fetal DNA is cleared from the maternal circulation within several hours, with an observed half-life of 16 minutes. Since 2000, many laboratories have developed assays that are sensitive and specific enough to genotype the fetus reliably using cell-free DNA isolated from maternal plasma. This assay is relatively simple for RHD, because in Caucasians D-negativity is caused by the complete absence of the RHD gene. However, due to the high frequency of variant RHD genes, especially in African blacks and Asians, the interpretation of the assay can be difficult. Most other blood groups are caused by SNPs, and the design of those assays is, therefore, technically more challenging. However, nowadays for most clinical blood group antigens (D, c, C, E, e, K, HPA-1a), reliable, non-invasive genotyping assays are offered worldwide on a routine basis, and invasive procedures for fetal blood group typing have become obsolete. In several European countries, large-scale feasibility studies have been performed to investigate whether non-invasive fetal RHD genotyping could be safely applied to restrict antenatal immunoprophylaxis to those D-negative women carrying D-positive fetuses. This would prevent the unnecessarily exposure of 40 percent of D-negative women to the small but non-negligible risk of infection with a blood-borne disease, as anti-D is still produced from plasma of hyperimmunised donors. Furthermore, worldwide supplies of RhD immunoglobulin are limited. Based on the promising outcomes of these studies, the Danish and Dutch government decided in 2010 and 2011, respectively, to implement fetal RHD typing. With our fully automated assay we encountered only eight false negative results in more than 25,000 tested pregnancies (0.03%, 95% CI: 0.01-0.05%). In the Netherlands, postnatal immunoprophylaxis is also now given based on the PCR result in week 27 of pregnancy, and no routine cord blood serology is performed anymore. Overall, this program is cost-effective in the Dutch setting. In several other European countries (e.g., Sweden, UK, France) studies are ongoing on the implementation of fetal RHD genotyping to guide prophylaxis. Disclosures:No relevant conflicts of interest to declare.

The structure and function of band 3 (AE1): recent developments (review).

This review discusses recent advances in our understanding of the structure, function and molecular genetics of the membrane domain of red cell anion exchanger, band 3 (AE1), and its role in red cell and kidney disease. A new model for the topology of band 3 has been proposed, which suggests the membrane domain has 12 membrane spans, rather than the 14 membrane spans of earlier models. The major difference between the models is in the topology of the region on the C-terminal side of membrane spans 1-7. Two dimensional crystals of the deglycosylated membrane domain of band 3 have yielded two and three dimensional projection maps of the membrane domain dimer at low resolution. The human band 3 gene has been completely sequenced and this has facilitated the study of natural band 3 mutations and their involvement in disease. About 20% of hereditary spherocytosis cases arise from heterozygosity for band 3 mutations, and result in the absence or decrease of the mutant protein in the red cell membrane. Several other natural band 3 mutations are known that appear to be clinically benign, but alter red cell phenotype or are associated with altered red cell blood group antigens. These include the mutant band 3 present in Southeast Asian ovalocytosis, a condition which provides protection against cerebral malaria in children. Familial distal renal tubular acidosis, a condition associated with kidney stones, has been shown to result from a novel group of band 3 mutations. The total absence of band 3 has been described in animals-occurring naturally in cattle and after targeted disruption in mice. Some of these severely anaemic animals survive, so band 3 is not strictly essential for life. Although the band 3-negative red cells were very unstable, they contained a normally-assembled red cell skeleton, suggesting that the bilayer of the normal red cell membrane is stabilized by band 3 interactions with membrane lipids, rather than by interactions with the spectrin skeleton.

Evidence that CDw108 membrane protein bears the JMH blood group antigen.

CDw108 is a cluster-of-differentiation antigen that resides on a glycosylphosphatidylinositol (GPI)-linked protein; it has not previously been shown to be expressed on red cells. JMH is a high-frequency red cell blood group antigen that resides on a GPI-linked protein of molecular weight similar to that bearing CDw108. The purpose of this study was to investigate whether CDw108 is expressed on red cells and whether it resides on the same membrane protein as does JMH. Murine monoclonal antibodies to CDw108, MEM-121 and MEM-150, as well as a murine monoclonal antibody and human antibodies to JMH were used in radioimmunoassay, inhibition assay, Western blotting, and monoclonal antibody-specific immobilization of erythrocyte antigen assay. MEM-121 and MEM-150 were found to bind to red cells, and MEM-150 blocked binding of human anti-JMH to red cells. Anti-CDw108 and anti-JMH identified red cell membrane proteins that were of similar size and that were absent from JMH-negative red cells on Western blotting. MEM-150 and MEM-121 also immobilized the same protein that reacted with human anti-JMH. CDw108 is expressed on red cells and resides on the same GPI-linked membrane protein as does the JMH blood group antigen.

ABH and Colton blood group antigens on Aquaporin-1, the human red cell water channel protein

The recent identification of the red cell water transporter (AQP1) has led to the identification of the "aquaporins", a new class of membrane proteins which function as water-selective transport proteins and are involved in many physiological processes. Identification of the chromosomal localization of the corresponding gene led to the recognition that AQP1 is the structural basis of the Colton blood group antigens. Analysis of individuals with the Colton null phenotype led to the recognition that homozygosity for knockout mutations in the corresponding gene is exceedingly rare but is without a significant clinical phenotype, predicting a redundancy in expression of other aquaporin homologs. These studies demonstrate the importance which molecular studies in red cell blood group antigens may play in diverse areas of biomedical research. Moreover, they provide another example that blood group antigens may be polymorphisms in functionally important proteins on the red cell surface.

No irregular erythrocyte antibodies observed after bone allografts in 144 patients.

Red cell blood group antigens present in bone allografts may cause the formation of irregular erythrocyte antibodies (IEA). In the literature, 4 such cases have been described; all were Rh(D) negative females who had received Rh(D) positive bone and had made anti-Rh(D). To investigate the immunization by red cells after bone allografting, a retrospective and a prospective study was carried out. Altogether 144 patients were tested for the presence of IEA, before as well as after obtaining frozen allogeneic bone in orthopedic or maxillo-facial surgery. In 9 patients, the tests disclosed IEA preoperatively. No new IEA were detected postoperatively in the 144 patients, including 30 Rh(D) negative patients who received Rh(D) positive bone. We conclude that formation of IEA is a rare phenomenon. Nevertheless, it is recommended to give only Rh(D) negative bone to Rh(D) negative girls and women of childbearing age.

Molecular biology of red cell blood group genes.

The explosion of new information and technology for probing the fine architecture of gene structure has already brought new insights into the varied phenotypic expression of red cell blood group antigens. Molecular biologic techniques will be increasingly applied to red cell antigens as well as blood group antigens on other blood cells. Not since the introduction of the Coombs reagent has such a powerful method been available with which to increase our understanding of the nature of blood cell antigens.

Feijao chumbinhoの植物性凝集素を用いたウシのFc式赤血球型出現頻度

<I>Feijao chumbinho</I>の植物性凝集素を用いたウシのFc式赤血球型出現頻度

Effect of pentoxifylline on Wrb antigen.

Pentoxifylline, a hemorrheologic agent that lowers whole blood viscosity by increasing red cell membrane deformability, recently was approved by the Food and Drug Administration for the treatment of intermittent claudication. The effect of this drug on the phenotypic expression of red cell blood group antigens was studied with cells collected from six patients with intermittent claudication. After in vivo treatment with pentoxifylline, the serologic expression of the Wrb antigen increased. Comparative studies, using hemagglutination titration techniques, with red cells collected before treatment and 1 month after treatment, showed an increase in titer of at least two tubes and an increase in score of greater than 10 in all six patient samples drawn after treatment. No in vivo serologic changes were observed in any of the other antigens studied (A, B, D, C, E, c, e, M, N, S, s, U, P1, Leb, K, k, Fya, Fyb, Jka, Jkb, Yta). Protein analysis (sodium-dodecylsulfate polyacrylamide gel electrophoresis, silver stain) of red cell membranes prepared from blood collected before treatment and 1 month after treatment showed an increase in band density in the 24,000 and 14,000 dalton regions in the samples drawn after treatment. In vitro treatment of red cells with pentoxifylline and one of its major metabolites did not affect the phenotypic expression of any of the antigens studied, including Wrb.

Status of major red cell blood group antigens on neutrophils, lymphocytes and monocytes.

Previous investigators have reported that a number of red cell (RBC) antigens are found on neutrophils (PMN) and lymphocytes. However, there is a lack of consensus in the literature. Furthermore, few data are available concerning the occurrence of RBC antigens on monocytes. To address this problem, leucocyte fractions prepared from donors of known RBC antigen phenotype were analysed by fluorescence flow cytometry. Based on recent reports that PMN do not express ABH antigens and on the data presented here, the occurrence of major RBC antigens on leucocytes may be defined as follows: (1) lymphocytes express A, B. Lea and Leb antigens, depending on the ABH secretor (Se) status of the donor; (2) ABH and Lewis antigens cannot be detected on monocytes and PMN regardless of Se status; (3) D, E, e, C, c, Fya, Fyb, Fy5, Jka, Jkb, Jk, K, k, M, N, S, s, U, Vel, Coa, Lan, Jk3Yta, Dib, Ge, Sc:1 or Lub antigens were not detected on lymphocytes, monocytes and PMN; (4) lymphocytes, monocytes and PMN all express I, i, P and P1 antigens. The absence of selected Rhesus, Duffy, Kell, Kidd and other antigens on PMN is at variance with some previous reports. Furthermore, the distribution of RBC antigens on lymphocytes and monocytes has not been previously characterized using immunofluorescence flow cytometry.