Haemolytic disease of the newborn due to maternal irregular antibodies in the Chinese population in Taiwan

Non-RhD alloimmunization in pregnancy: an updated review

RhD alloimmunization in pregnancy is still the main cause of hemolytic disease of the fetus and neonate (HDFN). Nevertheless, there are other antigens that may be associated with the occurrence of this phenomenon and that have been growing in proportion, given that current prevention strategies focus only on anti-RhD antibodies. Although not widespread, the screening and diagnostic management of the disease caused by these antibodies has recommendations in the literature. For this reason, the following review was carried out with the objective of listing the main red blood cell antigen groups described - such as Rh, ABO, Kell, MNS, Duffy, Kidd, among others - addressing the clinical importance of each one, prevalence in different countries, and recommended management when detecting such antibodies during pregnancy.

Irregular Antibody Screening Using a Microdroplet Platform

The screening procedure for antibodies is considered the most tedious among the three pretransfusion operations, i.e., ABO and Rhesus (Rh) typing, irregular antibody screening/identification, and crossmatching tests. The commonly used screening method for irregular antibodies in clinics at present is a manual polybrene test (MP). The MP test involves numerous reagent replacement and centrifuge procedures, and the sample volume is expected to be relatively less. Herein, screening red blood cells (RBCs) and serum irregular antibodies are encapsulated in microdroplets with a diameter of ~300 μm for a hemagglutination reaction. Owing to the advantage of spatial limitation in microdroplets, screening RBCs and irregular antibodies can be directly agglutinated, thereby eliminating the need for centrifugation and the addition of reagents to promote agglutination, as required by the MP method. Furthermore, the results for a large number of repeated tests can be concurrently obtained, further simplifying the steps of irregular antibody screening and increasing accuracy. Eight irregular antibodies are screened using the proposed platform, and the results are consistent with the MP method. Moreover, the volume of blood samples and antibodies can be reduced to 10 μL and 5 μL, respectively, which is ten times less than that using the MP method.

Hemolytic disease of the fetus and newborn due to minor blood group alloimmunization in a mother of sickle cell disease with multiple alloantibodies

Hemolytic disease of the fetus and newborn is due to maternal IgG antibodies that transport through the placenta and destroy neonatal red cells. A mismatch of antigens between mother and fetus causes isoimmunization resulting in mild anemia, which may progress to fetal hydrops in the intrauterine period and severe hyperbilirubinemia to kernicterus in neonates. The isoimmunization is mainly caused by Rh-D and ABO antibodies. In this case report, we found neonatal hyperbilirubinemia due to the presence of anti-c alloantibody previously developed in a sickle cell disease (SCD) pregnant female. It is an unusual case of fetal hyperbilirubinemia due to minor blood group alloimmunization in a SCD needing exchange transfusion. Multi-transfused patients should be counseled regarding the need to perform antibody screening frequently before pregnancy for better treatment of both mother and child.

Fetal and neonatal outcome in severe alloimmunization managed with intrauterine transfusion: 18-year experience in a tertiary referral hospital in China

Background

Hemolytic disease of the fetus and newborn (HDFN) due to red cell alloimmunization, is an important cause of fetal and neonatal morbidity and mortality. However, fetal and neonatal outcome of HDFN managed with intrauterine transfusion (IUT) in China are unknown. In addition, fetal and neonatal outcomes according to the type of maternal red cell alloantibodies involved and outcomes of hydrops fetalis are also unclear.

Objectives

The objective of this study was to evaluate fetal and neonatal outcomes of severe red-cell alloimmunization treated by IUT, to compare the outcomes according to the type of antibody, and to investigate the perinatal and postnatal outcomes of hydrops fetalis due to red cell alloimmunization.

Methods

A retrospective study of pregnancies affected by HDFN and managed with IUT at a tertiary care university hospital in China between January 2001 and December 2018 was performed. Fetal and neonatal outcomes were investigated, and comparison of outcomes depending on the type of antibody and comparison of outcome between hydrops fetalis and fetuses without hydrops were also conducted.

Results

244 IUTs were performed in 81 fetuses from 80 pregnancies. Anti-RhD was the major etiology of HDFN requiring IUT (71.6%). The fetal survival rate was 90.1%. The survival rate of the hydropic fetuses was significantly lower than those of the non hydropic fetuses (61.2% vs. 95.6%) (P = 0.002**). Compared with non hydropic fetuses, hydropic fetuses had significantly lower gestational age and lower hemoglobin level at first IUT. The neonatal survival rate was 98.6%. Exchange transfusions were required in 26% of the neonates. 30.1% of neonates had late anemia and required top-up transfusions, and hydropic fetuses required more late top-up transfusions than fetuses without hydrops. No significant difference in fetal and neonatal outcomes was found among the four subgroups stratified by the antibody involved.

Conclusion

Our study demonstrates that IUT is an effective and safe therapy for severe HDFN at our institution. Early detection and treatment of hydrops is critical for perinatal outcomes. Particular attention should be paid to late postnatal anemia in affected neonates and top-up transfusion is still commonly needed.

Upregulation of miR-181a-5p and miR-125b-2-3p in the Maternal Circulation of Fetuses with Rh-Negative Hemolytic Disease of the Fetus and Newborn Could Be Related to Dysfunction of Placental Function

The transplacental transfer of maternal antibodies to the fetus is a critical mechanism for infant protection and perinatal disease. Hemolytic disease of the fetus and newborn (HDFN) is a representative fetal disease caused by transplacental transfer of maternal IgG antibodies. However, it is unclear whether placental-related miRNAs are expressed in Rh-HDFN. Through the investigation of the miR-181a-5p and miR-125b-2-3p levels in maternal plasma using qPCR, we found that both miR-181a-5p and miR-125b-2-3p were highly expressed in maternal plasma of newborns with Rh-HDFN compared with healthy controls, indicating the potential roles of these two miRNAs in Rh-HDFN. To demonstrate whether dysregulation of miR-125b-2-3p and miR-181a-5p contributes to Rh-HDFN development, we analyze the placental miRNA-/mRNA sequencing data (GSE73714) using weighted gene coexpression network analysis (WGCNA), miRNA target predictive databases, and DAVID (Database for Annotation, Visualization, and Integrated Discovery). The results showed that miR-125b-2-3p and miR-181a-5p could regulate several biological processes including cytoplasmic microtubule organization and angiogenesis. Moreover, core promoter sequence-specific DNA binding and protein binding were highly enriched molecular functions, indicating the potential roles of transcriptional regulation. Further pathway enrichment showed that miR-181a-5p and miR-125b-2-3p could regulate several biological pathways that were closely related to placental function, including the FoxO signaling pathway, focal adhesion, mTOR signaling pathway, and central carbon metabolism in cancer. In conclusion, the present results first revealed miRNA expression in the maternal circulation of newborns with Rh-HDFN, which could be caused by dysfunction of the placenta.

Hemolytic disease of the fetus and newborn caused by irregular antibody: A mortality case report and case series during the past 15 years in NCKUH

OBJECTIVE

Hemolytic disease of the fetus and newborn (HDFN) caused by irregular antibodies is a rare, but possibly life-threatening condition. We report a case of severe intrauterine hemolysis caused by anti-E alloimmunization, and review 16 cases in the past 15 years of our hospital.

CASE REPORT

A woman with gestational age 28 weeks and 5 days, received emergent Cesarean section because of fetal distress. The baby was expired at the next day after delivery and the comprehensive study showed severe anemia and alloimmunization related hemolysis caused by anti-E due to high antibody titer (1: 4096).

CONCLUSION

Anti-E antibody is one of the most common non-Rhesus D antibodies in the pathogenesis of HDFN, but rarely leads to severe hemolysis. However, our case has the highest reported anti-E titer in HDFN and is the first case of mortality during the past 15 years in NCKUH.

Non-Invasive Prenatal Fetal Blood Group Genotype and Its Application in the Management of Hemolytic Disease of Fetus and Newborn: Systematic Review and Meta-Analysis

Hemolytic disease of fetus and newborn (HDFN) imposes great healthcare burden being associated with maternal alloimmunization against parental-inherited fetal red blood cell antigens causing fetal anemia or death. Noninvasive prenatal analysis (NIPT) provides safe fetal RHD genotyping for early identification of risk pregnancies and proper management guidance. We aimed to conduct systematic review and meta-analysis on NIPT's beneficial application, in conjunction with quantitative maternal alloantibody analysis, for early diagnosis of pregnancies at risk. Search for relevant articles was done in; PubMed/Medline, Scopus, and Ovid (January 2006April 2020), including only English-written articles reporting reference tests and accuracy data. Nineteen eligible studies were critically appraised. NIPT was estimated highly sensitive/specific for fetal RHD genotyping beyond 11-week gestation. Amplifications from ≥2 exons are optimum to increase accuracy. NIPT permits cost-effectiveness, precious resources sparing, and low emotional stress. Knowledge of parental ethnicity is important for correct NIPT result interpretations and quantitative screening. Cut-off titer ≥8-up-to-32 is relevant for anti-D alloantibodies, while, lower titer is for anti-K. Alloimmunization is influenced by maternal RHD status, gravida status, and history of adverse obstetrics. In conclusion, NIPT allows evidence-based provision of routine anti-D immunoprophylaxis and estimates potential fetal risks for guiding further interventions. Future large-scale studies investigating NIPT's non-RHD genotyping within different ethnic groups and in presence of clinically significant alloantibodies are needed.

Successful prenatal management of two foetuses affected by antibodies against GP.Mur with prenatal genotyping analysis and a literature review

BACKGROUND

GP.Mur belongs to the GP(B-A-B) hybrid glycophorin family, which is the most common hybrid glycophorin in Southeast Asia. Antibodies against GP.Mur may cause a clinically significant haemolytic disease of the foetus and newborn (HDFN) although, so far, not many cases have been reported in mainland China.

MATERIALS AND METHODS

Two Chinese women with a history of severe hydrops foetalis were seen in our centre. Alloantibody identification and GYP.Mur genotyping analysis were used for prenatal evaluation. Intrauterine transfusion was performed in two pregnancies in case 1. The features of these two women are described and literature-reported cases of HDFN related to antibodies against GP.Mur are summarised.

RESULTS

The phenotype of both mothers was Mi^a- Mur-, while the fathers' was Mi^a+ Mur+ with a heterozygous GYP.Mur hybrid gene as determined by a high-resolution melting method of genotyping. In case 1, the antibodies against GP.Mur were detected in the mother's serum and the cord blood of two foetuses. Fortunately, the latest foetus was successfully saved after intrauterine transfusion. In case 2, hydrops foetalis occurred in the first two pregnancies, but the risk of HDFN was excluded for the third foetus because of the GP.Mur negative phenotype. The literature review showed that 68.8% (11/16) of the reported cases of HDFN related to antibodies against GP.Mur occurred in the Chinese population, and that 37.5% (6/16) of them were cases of severe HDFN.

DISCUSSION

More cases of severe HDFN caused by antibodies against GP.Mur are presumably undetected as GP.Mur cells are not included in the panel of obligatory screening tests in most Southeast Asian countries including mainland China. The high-resolution melting method for GYP.Mur genotyping and zygosity detection is helpful in prenatal management.

Minor blood group incompatibility due to blood groups other than Rh(D) leading to hemolytic disease of fetus and newborn: a need for routine antibody screening during pregnancy

Minor blood group incompatibility due to blood groups other than Rh(D), although an uncommon cause of neonatal hyperbilirubinemia, has the potential to cause severe hyperbilirubinemia and its sequelae in infants, if left undiagnosed and untreated. Here, we describe clinical presentation, diagnosis and treatment of three cases of minor blood group incompatibility due to anti-E and anti-c antibody. All three neonates presented with pallor, icterus and splenomegaly within the first three days of life. Investigations showed indirect hyperbilirubinemia and a positive direct coombs test. Indirect coombs test was positive in the mothers. There was no setting of ABO or Rh(D) incompatibility in any of the neonates. When tested for minor blood group incompatibility, anti E antibody was found to be responsible for hemolysis and hyperbilirubinemia in the first case, and anti c antibody was found in the second case and third case had both anti c and anti E antibodies. While hyperbilirubinemia improved with intensive phototherapy in the first two cases, the third case required a double volume exchange transfusion. On follow up, bilateral sensorineural hearing loss was seen in one of the patients. All three neonates were otherwise healthy, gaining weight and developmentally normal.

Hybrid glycophorin and red blood cell antigen genotyping in Asian American type O blood donors with Mia phenotype

BACKGROUND

The GP.Mur glycophorin with Mi^a phenotype is relatively common and clinically significant in the Southeast Asian populations. The aim of this study is to genotype Mi^a -positive Asian American type O blood donors. Red blood cell (RBC) minor antigens were also determined in the same cohort.

STUDY DESIGN AND METHODS

Asian American blood donors of the Gulf Coast Regional Blood Center (Houston, TX) were screened using a typing reagent (NOVACLONE Anti-Mi^a Monoclonal IgG Typing Reagent, Dominion Biologicals Ltd) from March 2016 to July 2018. Aliquots of Mi^a -positive blood from type O donors were subjected to serologic confirmation using Mi^a - and/or Mur-specific GAMA210 and 64D6 monoclonal antibodies, and two human antisera. Extracted genomic DNA was amplified by polymerase chain reaction (PCR) using GYP hybrid gene/allele-specific primers followed by bidirectional Sanger sequencing. Zygosity for GYP*Mur and GYP*Bun was determined using TaqMan real-time PCR assay. Phenotypes of 35 RBC antigens and three phenotypic variants were determined with use of an in vitro diagnostic test, PreciseType HEA Molecular BeadChip Test (Immucor).

RESULTS

By screening 4600 blood donations in the Houston metropolitan area, 209 samples from 103 unique donors were identified to be Mi^a -positive. By PCR and sequencing analysis, 97 of the 103 Mi^a -positive donors carried hybrid genes GYP*Mur (89.7% including two homozygotes), GYP*Bun (6.2%), GYP*Vw (3.1%) and GYP*Hut (1.0%). Concordance between serology and DNA analysis was 98%, 99%, and 100% for the GAMA210, 64D6, and human antisera, respectively. Genotyping of RBC antigens showed that the Mi^a -positive donors were predominantly associated M+ N- S- s+ (48.5%) and M+ N+ S- s+ (38.1%) phenotypes.

CONCLUSIONS

The GP.Mur glycophorin is most prevalent in the Mi^a -positive Asian American type O blood donors.

Effects of cooperative blood transfusion and homologous blood transfusion on the production of red blood cell irregular antibodies in obstetric patients

Effects of cooperative blood transfusion and homologous blood transfusion on the production of red blood cell irregular antibodies in obstetric patients were investigated. A total of 300 obstetric patients who underwent blood transfusion in the Maternity and Child Health Care of Zaozhuang from February 2016 to February 2018 were enrolled. There were 150 obstetric patients receiving the same type of transfusion who were included in the control group. Due to special circumstances the remaining 150 obstetric patients with ABO and Hr with cooperative blood transfusion were included in the research group. The positive detection rate of blood cell irregular antibody, the effectiveness of blood transfusion and the incidence of adverse transfusion reaction were observed in the two groups after the comparison of blood transfusion of both groups. The total positive detection rate of erythrocyte irregular antibody in the research and control groups was not statistically significant (P>0.05). There were no significant differences in the red blood cell counts, hemoglobin concentration, hematocrit and platelet count between the research and control groups after infusion (P>0.05). Comparing all the groups, the red blood cell counts, hemoglobin concentration, hematocrit and platelet count after infusion in both the research and control groups were significantly higher than before the infusion, and differences were statistically significant (P<0.001). There was no significant difference in the incidence of adverse reactions between the two groups (P>0.05). The effect of blood transfusion and homologous blood transfusion on the positive detection rate of red blood cell irregular antibody in obstetric patients, the efficiency of blood transfusion and the incidence of adverse transfusion reactions are similar, and all have high clinical application value.

Molecular Detection of Glycophorins A and B Variant Phenotypes and their Clinical Relevance

Crossover or conversion between the homologous regions of glycophorin A (GYPA) and glycophorin B (GYPB) gives rise to several different hybrid glycophorin genes encoding a number of different glycophorin variant phenotypes which bear low prevalence antigens in the MNS blood group system. GP.Mur is the main glycophorin variant phenotype which causes hemolytic transfusion reaction (HTR) and hemolytic disease of the fetus and newborn (HDFN) in East and Southeast Asians. The detection of glycophorin variant phenotypes using serological methods is limited to phenotyping reagents that are not commercially available. Moreover, the red blood cells used for antibody identification are usually of the GP.Mur phenotype. The current Polymerase Chain Reaction (PCR)-based methods and loop-mediated isothermal amplification (LAMP) are available alternatives to phenotyping that allow for the specific detection of glycophorin variant phenotypes. This review highlights the molecular detection method for glycophorins A and B variant phenotypes and their clinical relevance.

Selection of GP. Mur antigen-negative RBC for blood recipients with anti-'Mia ' records decreases transfusion reaction rates in Taiwan

OBJECTIVES

To evaluate the clinical significance of GP. Mur antigen-negative blood selection for transfusion in patients with anti-'Mi^a ' records.

BACKGROUND

The GP. Mur RBC phenotype is prevalent (7·3%) in Taiwan. Antibodies against GP. Mur (anti-'Mi^a ') are identified in 1·24% of our population, and anti-'Mi^a ' screening using GP. Mur RBC has been routine for Taiwan's blood banks. However, due to the lack of commercial antibodies, only cross-matching was used to prevent transfusion of GP. Mur-positive blood to patients with anti-'Mi^a ' in most hospitals. There is still a risk of GP. Mur-positive RBC exposure and subsequent anti-'Mi^a '-related transfusion reactions.

METHODS

Since February 2014, GP. Mur antigen-negative RBCs identified by reaction with anti-'Mi^a '-positive serum were selected for blood recipients with anti-'Mi^a ' records. The transfusion reactions between January 2013 and January 2014 were compared with those that occurred between February 2014 and July 2015.

RESULTS

The transfusion reaction rate was significantly higher in anti-'Mi^a '-positive blood recipients compared to total subjects receiving an RBC transfusion before GP. Mur-negative donor RBC selection. After antigen-negative RBC selection, the transfusion reaction frequency in subjects with anti-'Mi^a ' became similar to total blood recipients. IgG form anti-'Mi^a ' antibodies were present in all cases of probable anti-'Mi^a '-related transfusion reactions. The time required for anti-'Mi^a ' boosting after transfusion was around 4-21 days.

CONCLUSION

Selection of GP. Mur-negative RBC for transfusion to patients with anti-'Mi^a ' records could decrease the rate of transfusion reaction and antibody boosting. This procedure should be incorporated into blood bank routines in areas where anti-'Mi^a ' is prevalent.

Anti-Mur as the most likely cause of mild hemolytic disease of the newborn

BACKGROUND

Although rare in the United States, anti-Mur is relatively common in Southeast Asia and has been reported to have clinical significance in Chinese and Taiwanese populations.

STUDY DESIGN AND METHODS

The infant was full term and the second child of a Chinese mother and Vietnamese father, presenting with jaundice. He was clinically diagnosed with immune-mediated hemolytic anemia.

RESULTS

The direct antiglobulin test indicated that the infant's red blood cells were coated only with anti-IgG. Anti-Mur was identified in the maternal serum and the neonate's plasma. The father was found to be positive for the Mur antigen. The cause of the infant's hemolytic anemia was determined to be most likely anti-Mur.

CONCLUSION

Since anti-Mur is implicated in causing hemolytic disease of the newborn, it is important to recognize this antibody more commonly found in Asian patients in the United States as the Mur+ phenotype has a higher prevalence in this population.

Hemolytic disease of fetus and newborn due to maternal red blood cell alloantibodies in the Malay population

Background:

Maternal red blood cell (RBC) alloimmunization may lead to production of harmful antibodies that result in hemolytic disease of fetus and newborn (HDFN). There is insufficient data on the prevalence of HDFN due to RBC alloantibodies in the Malay neonatal population.

Aim:

The aim of this study was to determine the incidence of HDFN in the Malay neonatal population due to clinically significant RBC alloantibodies.

Subjects and Methods:

A cross sectional study was conducted in Transfusion Medicine Unit, Hospital Universitiy Sains Malaysia over one year period from January to December 2009. A total of 5163 Malay pregnant women who attended labor room for delivery were collected and analyzed prospectively. The blood samples were subjected to the standard immunohematological procedure for RBC antibody screening and identification using reagents of Diamed-ID Gel microtyping system. All the newborns with RBC alloantibody were investigated for the evidence of HDFN.

Results:

Thirty (0.58%) women were found to have clinically significant RBC alloantibodies. Most of the alloantibodies belonged to Rhesus (Rh) system (56.7%) where anti-E (33.3%) was the most common followed by anti-D (10.0%). Rh antibodies were the main cause of HDFN in fourteen (0.27%) neonates. Anti-D and anti-c were identified to cause moderate to very severe HDFN.

Conclusions:

With the low prevalence of clinically significant RBC alloantibodies and HDFN, routine antenatal antibody screening practice may not be advised as a routine practice at present, preferably reserved for those women of RhD negative or with history of HDFN, significantly of those attributed to anti-c.

The risk assessment study for hemolytic disease of the fetus and newborn in a University Hospital in Turkey

Maternal red-cell alloimmunization occurs when a woman's immune system is sensitized to foreign red-blood cell surface antigens, leading to the production of alloantibodies. The resulting antibodies often cross the placenta during pregnancies in sensitized women and, if the fetus is positive for red-blood-cell surface antigens, this will lead to hemolysis of fetal red-blood cells and anemia. The most severe cases of hemolytic disease in the fetus and newborn baby are caused by anti-D, anti-c, anti-E and anti-K antibodies. There are limited data available on immunization rates in pregnant women from Turkey. The aim of the present study was to provide data on the frequency and nature of maternal RBC alloimmunization in pregnant women in a tertiary care hospital. In this study, we retrospectively evaluated the indirect antiglobulin test results of Rh-negative pregnant women performed in our Blood Bank between 2006 and 2012. Indirect antiglobulin test positive women also underwent confirmatory antibody screening and identification. During the study period, 4840 women admitted to our antenatal clinics. With regards to the major blood group systems (ABO and Rh), the most common phenotype was O positive (38.67%). There were 4097 D-antigen-positive women (84.65%) and 743 women with D-antigen-negative phenotype (15.35%). The prevalence of alloimmunization was found to be 8.74% in D-antigen negative group. Despite prophylactic use of Rh immunglobulins, anti-D is still a common antibody identified as the major cause of alloimmunization in our study (anti-D antibody 68.57%, non-D antibody 31.42%). While alloimmunization rate to D antigen was 6.46%, non-D alloimmunization rate was 2.69% among Rh-negative pregnant women. Moreover, detailed identification facilities for antibodies other than anti-D are not available in most of centers across Turkey. However, large-scale studies on pregnant women need to be done in order to collect sufficient evidence to formulate guidelines and to define indications for alloantibody screening and identification.

The prevalence of irregular erythrocyte antibodies among antenatal women in Delhi

BACKGROUND

Universal screening of all antenatal women, including D antigen-positive pregnant ones, is mandatory in most developed countries. However, no guidelines on this issue are available for developing countries such as India. Furthermore, there is limited information on immunisation rates in pregnant women (D antigen-positive and D antigen-negative) from India. We, therefore, studied the prevalence of alloantibodies among multigravida women in India.

MATERIALS AND METHODS

In this prospective study, carried out to detect the prevalence of alloantibodies among multigravida women in India, 3,577 multigravida women attending antenatal clinics were typed for ABO and D antigens and screened for alloantibodies by column agglutination technology. The medical history and detailed obstetric history of these women were reviewed and information recorded on any prior haemolytic disease of the foetus and newborn among siblings and/or blood transfusions.

RESULTS

The overall prevalence of alloantibodies in this study was 1.25%. There was a statistically significant difference between alloimmunisation rates in the D antigen-negative and D antigen-positive groups (10.7% versus 0.12%, respectively). Anti-D antibody contributed to 78.4% of total alloimmunisations in our study.

DISCUSSION

Anti-D was the most common culprit responsible for alloimmunisation. Other alloantibodies found included anti-C, anti-M, anti-S and anti-c. Large-scale population-based studies are required to assess the real magnitude of alloimmunisation in pregnant women in India.

Hemolytic disease of the fetus and newborn: Current trends and perspectives

The spectrum of hemolytic disease of the newborn has changed over the last few decades. With the implementation of Rhesus D immunoprophylaxis, hemolytic disease due to ABO incompatibility and other alloantibodies has now emerged as major causes of this condition. Though in developing countries, anti D is still a common antibody in pregnant women, many Asian countries have identified alloantibodies other than anti D as a cause of moderate-severe hemolytic disease. The most concerned fact is that, some of these have been described in Rh D positive women. It appears that universal antenatal screening in all pregnant women needs to be initiated, since Rh D positive women are just as likely as D negative women to form alloantibodies. Many developed nations have national screening programs for pregnant women. This is necessary to ensure timely availability of antigen negative blood and reduce effects on the newborn. Although universal screening seems justified, the cost and infrastructure required would be immense. Developing countries and under resourced nations need to consider universal antenatal screening and frame guidelines accordingly.

Prevalence and specificity of red-blood-cell antibodies in a multiethnic South and East Asian patient population and influence of using novel MUT+Mur+ kodecytes on its detection

BACKGROUND AND OBJECTIVES

Appropriate screening for irregular red-cell antibodies is essential for ensuring transfusion compatibility and for antenatal management of mothers at risk of haemolytic disease of the foetus and newborn. Screening for all relevant antibodies is, however, limited by screening cells that do not express antigens present in the patient and donor population. Technology to artificially incorporate antigens into red cells is currently available and may be an option for customizing screening cells.

MATERIALS AND METHODS

We sought to identify retrospectively the changing patterns of alloantibody prevalence in our multiethnic population on change of screening cells. Antibody screening records of 143 501 patients tested from 2004 to 2010 were retrieved and divided into two groups: period-1 (2004-2008) and period-2 (2009-2010). During period-1, standard screening cells were used while in period-2, MUT+Mur+ KODE(™) transformed red cells (kodecytes) were used.

RESULTS

Four per cent of samples tested during period-2 were positive on antibody screening compared to 3·2% in period-1. Specific antibodies, excluding anti-D, were identified in 1·66% and 1·52% of patients in period-2 and -1, respectively. When confined to antibodies of clinical significance only, period-2 showed higher alloantibody prevalence of 1·16% as compared to 0·66% in period-1. Antibodies to glycophorin variants of MNS (vMNS) were more commonly detected while antibodies to Lewis antigens declined during period-2.

CONCLUSION

  Antibodies to vMNS antigens are common in South and East Asian populations and are often missed when using standard screening cells. Use of specifically engineered screening cells to express red-cell antigens artificially is beneficial in detecting the diverse alloantibodies present in our population.

Sixty years of antibodies to MNS system hybrid glycophorins: what have we learned?

The MNS system was the second blood group system discovered and at least 16 of the 46 antigens in the MNS system result from genetic recombination, producing a hybrid glycophorin. The incidence of these hybrid glycophorins is highest in East Asian populations. MNS system antigens defined by hybrid glycophorins are immunogenic with alloimmune IgG responses developing after transfusion or pregnancy; with reports originating from Asia, Europe, the Americas, and Australia. This demonstrates the global nature of problems associated with these antibodies. Since the initial report that production of anti-Mi(a) was a cause of hemolytic disease of the fetus and newborn (HDFN), antibodies to antigens defined by hybrid glycophorins have been reported in 27 cases of HDFN (1 fatal) and 8 cases of hemolytic transfusion reaction (HTR) (1 fatal). In at least 40% of these clinical cases, the disease was reported as severe. Hyporegenerative fetal anemia is a common feature of the reported HDFN cases. In all published cases, the causative antibodies were identified by reference laboratory investigative tests following clinical presentation. The failure to detect these antibodies by routine testing highlights the need for consideration of the medical importance of these antibodies when defining antibody screening practices and reagents. The aim of this review is to raise awareness of severe disease caused by antibodies to MNS antigens defined by hybrid glycophorins and, thus, to improve diagnosis and patient management.

Management of Pregnancies Complicated by Anti-E Alloimmunization

OBJECTIVE

There is limited information published about anti-E alloimmunization. We review our experience at The Ohio State University to determine appropriate management strategies.

METHODS

We reviewed records from June 1959 to April 2004 to identify pregnancies managed for anti-E alloimmunization. Information collected included antibody titers, DeltaOD450 values, Liley zones, middle cerebral artery peak systolic velocity, fetal and neonatal hemoglobin (Hb) and antigen typing, fetal and neonatal direct antiglobulin test, and outcomes. Pregnancies affected only by anti-E alloimmunization with a positive direct antiglobulin test or positive E antigen typing in the fetus or newborn were included.

RESULTS

A total of 283 pregnancies were identified with anti-E. Of these, 32 pregnancies in 27 women were at risk for hemolytic disease of the fetus or newborn from anti-E only and had complete records. Sixteen of these pregnancies had titers greater than or equal to 1:32, with amniocenteses performed for DeltaOD450 in 15 pregnancies. Values of DeltaOD450 in zone IIB or zone III in combination with serologic titers identified all pregnancies with fetal or neonatal anemia. Five of 32 (15%) fetuses had Hb less than 10 g/dL and 1 fetus had hydrops fetalis due to anti-E alloimmunization. There was 1 perinatal death attributable to anti-E hemolytic disease of the fetus or newborn. Middle cerebral artery peak systolic velocity was measured in 2 cases and corroborated information obtained from amniocentesis.

CONCLUSION

Anti-E alloimmunization can cause hemolytic disease of the fetus or newborn requiring prenatal intervention. Based on our population, clinical strategies developed for Rh D alloimmunization using maternal serology, amniotic fluid spectrophotometry, and fetal blood sampling are useful in monitoring E alloimmunization.