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

Maternal red blood cell alloimmunization prevalence in the United States

ABSTRACT

Hemolytic disease of fetus and newborn (HDFN) is a life-threatening disease mediated by maternal alloimmunization to red blood cell (RBC) antigens. Studies of maternal alloimmunization prevalence in the United States lack national data. This study describes prevalence and trends in alloimmunization in pregnancy in the United States. RBC antibodies (abs) were identified in a large, nationwide, commercial laboratory database from 2010 through 2021. The cohort comprised pregnancies for which the year of laboratory collection and patient's state of residence were available. Data were normalized based on US Centers for Disease Control and Prevention estimates of live births and weighted by year and US Census Division. Cochrane-Armitage tests assessed temporal trends of alloimmunization. Of 9 876 196 pregnancies, 147 262 (1.5%) screened positive for RBC abs, corresponding to an estimated prevalence of 1518 of 100 000 pregnancies. Of identified RBC abs, anti-D comprised 64.1% pregnancies (586/100 000). Prevalence of other high-risk RBC abs for HDFN included anti-K (68/100 000) and anti-c (29/100 000). Incidence of all 3 high-risk abs increased from 2010 to 2021 (all P < .001). Among almost 10 million pregnancies in the United States, comprising an estimated 14.4% of all pregnancies, 1.5% screened positive for RBC abs. Almost three-quarters (679/100 000 [74.3%]) of RBC abs identified were high risk for HDFN. Although prevalence of anti-D is difficult to interpret without the ability to distinguish alloimmunization from passive immunity, it remains problematic in HDFN, ranking second only to anti-K in critical titers. Given the sequelae of HDFN, new initiatives are required to reduce the incidence of alloimmunization in patients of reproductive potential.

Hemolytic disease of the fetus and newborn-a perspective of immunohematology

BACKGROUND

Hemolytic disease of the fetus and newborn is a public health problem caused by maternal-fetal incompatibility; no prophylaxis is available for most alloantibodies that induce this disease. This study reviews the literature regarding which antibodies are the most common in maternal plasma and which were involved in hemolytic disease of the fetus and newborn.

METHOD

Seventy-five studies were included in this review using a systematic search. Two independent authors identified studies of interest from the PubMed and SciELO databases.

MAIN RESULTS

Forty-four case reports were identified, of which 11 babies evolved to death. From 17 prevalence studies, the alloimmunization rate was 0.17 % with 161 babies receiving intrauterine transfusions and 23 receiving transfusions after birth. From 28 studies with alloimmunized pregnant women (7616 women), 455 babies received intrauterine transfusions and 21 received transfusions after birth.

CONCLUSION

Rh, Kell, and MNS were the commonest blood systems involved. The geographical distribution of studies shows that as these figures vary between continents, more studies should be performed in different countries. Investing in early diagnosis is important to manage the risks and complications of hemolytic disease of the fetus and newborn.

The influence of HLA allele and haplotype on RhE alloimmunization among pregnant females in the Chinese Han population

BACKGROUND AND OBJECTIVES

Anti-E alloantibody is the most common and important red blood cell (RBC) alloantibody during pregnancy. The study aimed to determine the correlation between RhE alloimmunization and human leukocyte antigen (HLA) allele polymorphism, as well as haplotype diversity, among pregnant individuals in the Chinese Han population.

STUDY DESIGN AND METHODS

All individuals included in our study were RhE-negative pregnant women of Chinese Han ethnicity, confirmed through serological testing. Pregnancy could be the only potential stimulating factor in RBC alloimmunization. Given the serological testing, the participants were divided into anti-E (responders) and non-anti-E-producing group (non-responders). The class I and II classical HLA genotyping were determined using next-generation sequencing, and the HLA genotype and haplotype frequencies were compared between the responders and non-responders.

RESULTS

In total, 76 responders and 94 non-responders were enrolled in this study. Comparison results showed that all HLA class I alleles had no difference between the two groups. For HLA class II phenotypes, responders had higher frequencies of HLA-DRB1*09:01, HLA-DQA1*03:02 and HLA-DQB1*03:03 phenotypes than non-responders, and the differences were statistically significant (pc < 0.05). In addition, the haplotype frequency of HLA-DRB1*09:01-DQA1*03:02-DQB1*03:03 in the RhE responders was significantly higher than in the non-responders (31.58% vs. 12.77%; odds ratio, 3.154; 95% confidence interval, 1.823-5.456; pc value, 1.25 × 10-3).

CONCLUSION

Our findings indicated that HLA-DRB1*09:01, HLA-DQA1*03:02 and HLA-DQB1*03:03 might be susceptible alleles for RhE alloimmunization among Chinese Han pregnant females. These three susceptible alleles constituted the unique three-locus haplotype in the RhE responders and collaborated to RhE alloimmunization.

Red Blood Cell Alloimmunization in Pregnancy: A Review of the Pathophysiology, Prevalence, and Risk Factors

This review paper provides an overview of the risk factors and laboratory testing for red blood cell (RBC) alloimmunization in pregnancy. RBC alloimmunization is a significant medical issue that can cause haemolytic disease of the fetus and newborn (HDFN), leading to neonatal morbidity and mortality. Current HDFN prophylaxis targets only Rhesus D (RhD) alloimmunization, with no effective measures to prevent alloimmunization to other RBC antigen groups. Several factors can increase the risk of developing RBC alloimmunization during pregnancy, including fetomaternal haemorrhage, RBC and maternal genetic status, and previous transfusions. Identifying these risk factors is essential to execute the appropriate management strategies to minimize the risk of HDFN. The review also discusses the laboratory methods and overview of pregnancy management. The paper highlights the importance of identifying and managing the risk factors for RBC alloimmunization in pregnancy to minimize the risk of HDFN and improve neonatal outcomes.

Different Types of Minor Blood Group Incompatibility Causing Haemolytic Disease of Neonates in one of the National Children's Medical Centre in China

Purpose

To review the neonatal cases with different types of minor blood group incompatible haemolytic diseases in China, and to improve the clinical understanding and management.

Materials and Methods

Seven cases from January, 1st, 2013 to December 31st, 2019 were searched out and reviewed retrospectively. All clinical data and laboratory findings were collected.

Results

There were totally seven cases enrolled including three cases of MNS, three of Diego, and one of Kidd combined with Rh, anti-RhE incompatibility. Among the seven cases, two had intrauterine transfusion, two underwent exchange transfusion, five received intravenous immune globulin, five cases developed anaemia, and three of them had transfusion. But among them, only four were found to have positive antibody screening and three were confirmed HDN with antibody types antenatally.

Conclusion

The clinical presentation is diverse. Antibody screening followed by the technique of peak systolic velocity in the fetal middle cerebral artery (MCA-PSV) helps to filter out the severe cases.

An Unusual Case of Hemolytic Disease of Newborn Due to ABO and Rh Isoimmunization

Anti-D is the most common cause of hemolytic disease of the newborn (HDN) in the developing countries even after the introduction of anti-D immunoprophylaxis. Still, ABO incompatibility and other alloantibodies against minor blood group antigens have emerged as significant causes of HDN. Moreover, ABO incompatibility acts as a protective barrier to the expression of Rh isoimmunization. Here we are presenting a case of HDN where both Rh and ABO incompatibility co-existed with their manifestations in a B positive neonate born to an O positive mother. Use of appropriate elution technique can aid in the diagnosis of such cases. Hence, antenatal screening of all mothers irrespective of their Rh D status can help in early diagnosis and proper management that can decrease the neonatal morbidity and mortality.

Immunohematologic aspects of alloimmunization and alloantibody detection: A focus on pregnancy and hemolytic disease of the fetus and newborn

Alloimmunization to non-ABO, red blood cell (RBC) antigens remains one of the most clinically-relevant complexities faced by blood banking practitioners. In the setting of transfusion therapy, these antibodies raise risks for incompatibilities, while for pregnant patients they can mediate deadly forms of hemolytic disease of the fetus and newborn. As such, a thorough understanding of pathways that lead to alloimmunization, as well as the tools used by blood banks to detect alloantibodies, is critical to transfusion practice. In this review, in which alloimmunization in the setting of pregnancy will be emphasized, we will review: 1) the clinical impacts of RBC alloantibodies in the peri-partum period; 2) the current pathophysiologic mechanisms thought to influence non-ABO antigen alloimmunization; 3) the strengths and weaknesses of laboratory tools used in aiding alloimmunization detection; and 4) future directions of the transfusion community related to alloimmunization impacting pregnancy.

The frequent and the unusual red cell phenotypes in Indian blood donors: A quest for rare donors

A clinically significant red cell alloantibody is capable of accelerated destruction of red cells bearing the corresponding antigen. Knowledge of prevalence of these antigens is necessary for performing day to day work and for research in immunohematology. The primary aim of this study was to find the prevalence of 18 clinically significant blood group antigens in blood donors. Secondary objectives were to motivate and create a database of accessible, volunteer O blood group donors and to register rare donors with existing registries. A cross-sectional observational study was conducted in the department of Transfusion Medicine at a large tertiary care hospital in India from October 2016 to May 2018 with a planned sample size of 4800. Study population included healthy blood donors of either gender coming for blood donation to the blood centre. A total of 6678 samples were included in the study. First time donors were 21.41 % while 78.59 % were repeat donors. Voluntary donors constituted 15.81 % while replacement donors were 84.19 %. Male donors were 89.82 % while female donors were 10.18 %. The antigen, phenotype and gene frequencies were calculated. An extended phenotyped voluntary donor database was created and four rare donors were identified. One of these rare donors was registered with the International Rare Donor Panel (IRDP) and rest were registered in a local registry. This study might help enhance the confidence of blood banks in finding appropriate units for patients with unexpected antibodies or with rare phenotypes. It also paves a way for registering rare donors locally and internationally.

Prevalence and specificity of clinically significant red cell alloantibodies in pregnant women - a study from a tertiary care hospital in Southeast Michigan

Background

Maternal red cell IgG antibodies can cross the placenta and cause hemolysis of fetal red cells in case of antigenic differences between maternal and fetal RBCs, leading to hemolytic disease of the fetus and newborn (HDFN). Although the incidence of anti-D associated HDFN has drastically reduced with Rh immune globulin prophylaxis, HDFN due to other maternal red cell alloantibodies still remains a concern. Prevalence and specificities of clinically significant red cell alloantibodies in pregnant females have rarely been reported in the USA.

Methods

A retrospective chart review was conducted to determine the prevalence and specificity of clinically significant red cell alloantibodies in pregnant females who delivered at Beaumont Hospital Royal Oak between May 1, 2017 and December 31, 2017. A total of 4548 pregnant females were screened using electronic medical records. One female above 50 years age and two females with invalid ABO type were excluded from the study per IRB approved protocol. The remaining 4545 pregnant females with a valid ABO/RhD type and valid red cell antibody screen were included.

Results

Out of the 4545 included females, 440 had a positive red cell antibody screen. Of these 440 females, 34 had clinically significant alloantibodies, giving an overall prevalence of 0.74%. Anti-E was the most frequently identified significant alloantibody followed by anti-K. The most prevalent significant alloantibodies in RhD positive and RhD negative females were anti-E and anti-K, respectively. Significant association (p-value <0.001) was found between RhD type and the presence of clinically significant alloantibodies amongst females with positive antibody screen.

Conclusion

Our study aims to reiterate the importance of maternal red cell antibody screening during early pregnancy to help identify and manage high-risk pregnancies. Minimizing the exposure of childbearing age females to incompatible red cell antigens through unnecessary transfusions can help reduce the incidence of red cell alloimmunization and the risk of HDFN.

Screening and identification of RhD antigen mimic epitopes from a phage display random peptide library for the serodiagnosis of haemolytic disease of the foetus and newborn

BACKGROUND

Identification of RhD antigen epitopes is a key component in understanding the pathogenesis of haemolytic disease of the foetus and newborn. Research has indicated that phage display libraries are useful tools for identifying novel mimic epitopes (mimotopes) which may help to determine antigen specificity.

MATERIALS AND METHODS

We selected the mimotopes of blood group RhD antigen by affinity panning a phage display library using monoclonal anti-D. After three rounds of biopanning, positive phage clones were identified by enzyme-linked immunosorbent assay (ELISA) and then sent for sequencing and peptides synthesis. Next, competitive ELISA and erythrocyte haemagglutination inhibition tests were carried out to confirm the inhibitory activity of the synthetic peptide. To evaluate the diagnostic performance of the synthetic peptide, a diagnostic ELISA was examined.

RESULTS

Fourteen of 35 phage clones that were chosen randomly from the titering plate were considered to be positive. Following DNA sequencing and translation, 11 phage clones were found to represent the same peptide - RMKMLMMLMRRK (P4) - whereas each of the other three clones represented a unique peptide. Through the competitive ELISA and erythrocyte haemagglutination inhibition tests, the peptide (P4) was verified to have the ability to mimic the RhD antigen. The diagnostic ELISA for P4 proved to be sensitive (82.61%) and specific (88.57%).

DISCUSSION

This study reveals that the P4 peptide can mimic RhD antigen and paves the way for the development of promising targeted diagnostic and therapeutic platforms for haemolytic disease of the foetus and newborn.

Frequency of Red Cell Alloantibodies in Pregnant Females of Navsari District: An Experience that Favours Inclusion of Screening for Irregular Erythrocyte Antibody in Routine Antenatal Testing Profile

Background

Alloimmunisation due to irregular erythrocyte antibodies is a recognised cause of hemolytic disease of the fetus and newborn (HDFN). Prior knowledge of red cell alloimmunisation in pregnant females guides the obstetrician to monitor the foetus for HDFN and if required for appropriated intervention. As limited data are available on prevalence of red cell alloimmunisation in pregnant females in India, the current study was carried out to know the prevalence of red cell alloimmunisation in pregnant females coming at our laboratory.

Methods

Screening for irregular erythrocyte antibodies was performed in 1960 pregnant females after obtaining informed consent between June 2015 and June 2016. MatrixTM screening and identification reagent red cells from Tulip Diagnostics (P) Ltd were used, and column agglutination technique was employed as a method for the test.

Results

Twenty antibodies (all of single specificity) were detected in 1960 samples giving a prevalence rate of alloimmunisation of 1.02%. Out of the 20 antibodies, 18 were identified to be anti-D, 1 was anti-c and 1 antibody was anti-H. The results obtained were then compared with those reported in the literature.

Conclusion

Red cell alloimmunisation is not uncommonly observed in pregnant females; the information gained can help the obstetrician to identify high-risk cases to timely start antenatal and post-natal treatment. Obstetricians should request screening for irregular red cell antibody desirably in all pregnant females; however, if limiting factors are there, it should be done at least in select group of pregnant females having bad obstetric history.