Laboratory Monitoring of Mother, Fetus, and Newborn in Hemolytic Disease of Fetus and Newborn

Antenatal RHD screening to guide antenatal anti-D immunoprophylaxis in non-immunized D- pregnant women

In pregnancy, D- pregnant women may be at risk of becoming immunized against D when carrying a D+ fetus, which may eventually lead to hemolytic disease of the fetus and newborn. Administrating antenatal and postnatal anti-D immunoglobulin prophylaxis decreases the risk of immunization substantially. Noninvasive fetal RHD genotyping, based on testing cell-free DNA extracted from maternal plasma, offers a reliable tool to predict the fetal RhD phenotype during pregnancy. Used as a screening program, antenatal RHD screening can guide the administration of antenatal prophylaxis in non-immunized D- pregnant women so that unnecessary prophylaxis is avoided in those women who carry a D- fetus. In Europe, antenatal RHD screening programs have been running since 2009, demonstrating high test accuracies and program feasibility. In this review, an overview is provided of current state-of-the-art antenatal RHD screening, which includes discussions on the rationale for its implementation, methodology, detection strategies, and test performance. The performance of antenatal RHD screening in a routine setting is characterized by high accuracy, with a high diagnostic sensitivity of ≥99.9 percent. The result of using antenatal RHD screening is that 97-99 percent of the women who carry a D- fetus avoid unnecessary prophylaxis. As such, this activity contributes to avoiding unnecessary treatment and saves valuable anti-D immunoglobulin, which has a shortage worldwide. The main challenges for a reliable noninvasive fetal RHD genotyping assay are low cell-free DNA levels, the genetics of the Rh blood group system, and choosing an appropriate detection strategy for an admixed population. In many parts of the world, however, the main challenge is to improve the basic care for D- pregnant women.

A novel pyrosequencing strategy for RHD zygosity for predicting risk of hemolytic disease of the fetus and newborn

OBJECTIVE

The aim of this study was the development of an accurate and quantitative pyrosequence (PSQ) method for paternal RHD zygosity detection to help risk management of hemolytic disease of the fetus and newborn (HDFN).

METHODS

Blood samples from 96 individuals were genotyped for RHD zygosity using pyrosequencing assay. To validate the accuracy of pyrosequencing results, all the samples were then detected by the mismatch polymerase chain reaction with sequence-specific primers (PCR-SSP) method and Sanger DNA sequencing. Serological tests were performed to assess RhD phenotypes.

RESULTS

Serological results revealed that 36 cases were RhD-positive and 60 cases were RhD-negative. The concordance rate between pyrosequencing assay and mismatch PCR-SSP assay was 94.8% (91/96). There were 5 discordant results between pyrosequencing and the mismatch PCR-SSP assay. Sanger sequencing confirmed that the pyrosequencing assay correctly assigned zygosity for the 5 samples.

CONCLUSION

This DNA pyrosequencing method accurately detect RHD zygosity and will help risk management of pregnancies that are at risk of HDFN.

Feasibility for non-invasive prenatal fetal blood group and platelet genotyping by massively parallel sequencing: A single test system for multiple atypical red cell, platelet and quality control markers

Non-invasive prenatal tests (NIPT) to predict fetal red cell or platelet antigen status for alloimmunised women are provided for select antigens. This study reports on massively parallel sequencing (MPS) using a red cell and platelet probe panel targeting multiple nucleotide variants, plus individual identification single nucleotide polymorphisms (IISNPs). Maternal blood samples were provided from 33 alloimmunised cases, including seven with two red cell antibodies. Cell-free and genomic DNA was sequenced using targeted MPS and bioinformatically analysed using low-frequency variant detection. The resulting maternal genomic DNA allele frequency was subtracted from the cell-free DNA counterpart. Outcomes were matched against validated phenotyping/genotyping methods, where available. A 2.5% subtractive allele frequency threshold was set after comparing MPS predictions for K, RhC/c, RhE/e and Fya /Fyb against expected outcomes. This threshold was used for subsequent predictions, including HPA-15a, Jka /Jkb , Kpa /Kpb and Lua . MPS outcomes were 97.2% concordant with validated methods; one RhC case was discordantly negative and lacked IISNPs. IISNPs were informative for 30/33 cases as controls. NIPT MPS is feasible for fetal blood group genotyping and covers multiple blood groups and control targets in a single test. Noting caution for the Rh system, this has the potential to provide a personalised service for alloimmunised women.

Effect of RhD and RhE sample phenotypic blood transfusion on the prognosis of hepatocellular carcinoma

OBJECTIVE

This study aimed to analyze the therapeutic effects and clinical outcomes of HCC patients, who received both RhD and RhE same phenotypic blood transfusion during perioperative period.

METHODS

Microcolumn gel technology (MGT) was used to detect Rh blood group phenotyping in 98 HCC patients. Patients received RhD and RhE same phenotypic transfusion were defined experimental group, and those received only RhD same phenotypic but RhE different phenotypic transfusion were included in control group. Hemoglobin (Hb) and hematocrit (HCT) before and after perioperative transfusion were analyzed. The occurrence of adverse transfusion reactions were observed. Survival analysis was performed using the Kaplan-Meier method.

RESULTS

After the transfusion treatment, the Hb (118.9 ± 34.8 g/L vs 99.6 ± 26.9 g/L) and HCT [(34.0 ± 7.6)% vs (29.9 ± 8.8)%] of experimental group and the Hb (104.3 ± 36.2 g/L vs 94.8 ± 25.0 g/L) of control group were significantly higher than those before blood transfusion, respectively (all P < .05). In addition, Hb and HCT in experimental group were significantly higher than those in the control group after transfusion (P < .05). For the adverse blood transfusion reactions, the incidence of backache was reduced in the patients received Rh same phenotypic transfusion compared with those in control group (1.9% vs 15.2%, P = .024). The overall survival of patients in experimental group was better than that in control group (log-rank P = .036).

CONCLUSION

Our study indicated that both RhD and RhE same phenotypic transfusion significantly increased Hb and HCT and reduced backache incidence than RhE different phenotypic transfusion in HCC patients. The overall survival of patients was improved by RhD and RhE same phenotypic transfusion.

Clinical value of combined predictors of RET%, γ-GT, LDH in the ABO neonatal hemolytic disease

Objective

The purpose of this study is to examine the prognostic significance of the amalgamated indicators, reticulocyte percentage (RET%), lactate dehydrogenase (LDH), and γ-Glutamyltransferase (γ-GT), in neonatal ABO hemolytic disease.

Methods

A total of 137 hospitalized children with pathological jaundice were included. Based on their medical conditions, they were categorized into two groups, hemolytic (67 cases) and non-hemolytic (70 cases). Pearson linear correlation and binary logistic multivariate analysis were used to analyze LDH, γ-GT, RET% and hemolysis. Furthermore, the predictive value of the combined predictors of RET%, LDH, and γ-GT on ABO neonatal hemolytic disease was evaluated using the ROC curve analysis.

Results

The laboratory indexes of the two groups were subject to analysis using binary logistic regression to identify suspicious influencing factors. The study revealed that RET%, LDH, and γ-GT were independent risk factors for hemolysis. Pearson linear correlation analysis indicated a positive correlation between LDH and γ-GT with RET% (r = 0.529, P < 0.01; r = 0.526, P = <0.01, respectively). Furthermore, the predictive value of each combined predictor was obtained using the ROC curve, and it was observed that combined predictor L (RET% + LDH + γ-GT)>L1 (RET% + LDH)>L2 (RET% + γ-GT).

Conclusion

Combined predictor L (RET% + LDH + γ-GT)demonstrate its optimal diagnostic efficacy, offering a novel approach towards diagnosing early-onset ABO hemolytic disease of the newborn.

Evaluation of an automated platform for non-invasive single-exon fetal RHD genotyping early in pregnancy

BACKGROUND

RhD immunization is still the major cause of hemolytic disease of the fetus and newborn. Fetal RHD genotyping during pregnancy followed by tailored anti-D prophylaxis for pregnant RhD-negative women carrying an RHD-positive fetus to prevent RhD immunization is a well-established practice in many countries. This study aimed to validate a platform for high-throughput, non-invasive, single-exon, fetal RHD genotyping consisting of automated DNA extraction and PCR set-up, and a novel system for electronic data transfer to the real-time PCR instrument. We also investigated the effect of storage conditions of fresh or frozen samples on the outcome of the assay.

MATERIALS AND METHODS

Blood samples from 261 RhD-negative pregnant women collected in Gothenburg, Sweden, between November 2018 and April 2020 during gestation week 10-14 were either tested as fresh after storage for 0-7 days at room temperature or as thawed plasma samples previously separated and stored for up to 13 months at -80°C. Extraction of cell-free fetal DNA and PCR set-up were performed in a closed automated system. Fetal RHD genotyping was determined by real-time PCR amplification of the RHD gene exon 4.

RESULTS

The outcome of RHD genotyping was compared with either the results obtained with serological RhD typing of newborns or with the results of RHD genotyping performed by other laboratories. No difference was observed in genotyping results when using fresh or frozen plasma during short- and long-term storage, revealing high stability of cell-free fetal DNA. The assay has shown high sensitivity (99.37%), specificity (100%), and accuracy (99.62%).

DISCUSSION

These data confirm that the proposed platform for non-invasive, single-exon, RHD genotyping early in pregnancy is accurate and robust. Importantly, we demonstrated the stability of cell-free fetal DNA in fresh and frozen samples after short- and long-term storage.

Hemolytic disease of the fetus and newborn: rapid review of postnatal care and outcomes

BACKGROUND

Advances in postnatal care for hemolytic disease of the fetus and newborn (HDFN) have occurred over the past decades, but little is known regarding the frequency of postnatal treatment and the clinical outcomes of affected neonates. Most studies reporting on HDFN originate from high-income countries or relatively large centers, but important differences between centers and countries may exist due to differences in prevalence and available treatment options. We therefore aimed to evaluate the postnatal treatment landscape and clinical outcomes in neonates with Rhesus factor D (Rh(D))- and/or K-mediated HDFN and to provide recommendations for future research.

METHODS

We conducted a rapid literature review of case reports and series, observational retrospective and prospective cohort studies, and trials describing pregnancies or children affected by Rh(D)- or K-mediated HDFN published between 2005 and 2021. Information relevant to the treatment of HDFN and clinical outcomes was extracted. Medline, ClinicalTrials.gov and EMBASE were searched for relevant studies by two independent reviewers through title/abstract and full-text screening. Two independent reviewers extracted data and assessed methodological quality of included studies.

RESULTS

Forty-three studies reporting postnatal data were included. The median frequency of exchange transfusions was 6.0% [interquartile range (IQR): 0.0-20.0] in K-mediated HDFN and 26.5% [IQR: 18.0-42.9] in Rh(D)-mediated HDFN. The median use of simple red blood cell transfusions in K-mediated HDFN was 50.0% [IQR: 25.0-56.0] and 60.0% [IQR: 20.0-72.0] in Rh(D)-mediated HDFN. Large differences in transfusion rates were found between centers. Neonatal mortality amongst cases treated with intrauterine transfusion(s) was 1.2% [IQR: 0-4.4]. Guidelines and thresholds for exchange transfusions and simple RBC transfusions were reported in 50% of studies.

CONCLUSION

Most included studies were from middle- to high-income countries. No studies with a higher level of evidence from centers in low-income countries were available. We noted a shortage and inconsistency in the reporting of relevant data and provide recommendations for future reports. Although large variations between studies was found and information was often missing, analysis showed that the postnatal burden of HDFN, including need for neonatal interventions, remains high.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2021 CRD42021234940. Available from:  https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021234940 .

Hemolytic disease of the fetus and newborn: systematic literature review of the antenatal landscape

BACKGROUND

Prevention of pregnancy-related alloimmunization and the management of hemolytic disease of the fetus and newborn (HDFN) has significantly improved over the past decades. Considering improvements in HDFN care, the objectives of this systematic literature review were to assess the prenatal treatment landscape and outcomes of Rh(D)- and K-mediated HDFN in mothers and fetuses, to identify the burden of disease, to identify evidence gaps in the literature, and to provide recommendations for future research.

METHODS

We performed a systematic search on MEDLINE, EMBASE and clinicaltrials.gov. Observational studies, trials, modelling studies, systematic reviews of cohort studies, and case reports and series of women and/or their fetus with HDFN caused by Rhesus (Rh)D or Kell alloimmunization. Extracted data included prevalence; treatment patterns; clinical outcomes; treatment efficacy; and mortality.

RESULTS

We identified 2,541 articles. After excluding 2,482 articles and adding 1 article from screening systematic reviews, 60 articles were selected. Most abstracted data were from case reports and case series. Prevalence was 0.047% and 0.006% for Rh(D)- and K-mediated HDFN, respectively. Most commonly reported antenatal treatment was intrauterine transfusion (IUT; median frequency [interquartile range]: 13.0% [7.2-66.0]). Average gestational age at first IUT ranged between 25 and 27 weeks. weeks. This timing is early and carries risks, which were observed in outcomes associated with IUTs. The rate of hydrops fetalis among pregnancies with Rh(D)-mediated HDFN treated with IUT was 14.8% (range, 0-50%) and 39.2% in K-mediated HDFN. Overall mean ± SD fetal mortality rate that was found to be 19.8%±29.4% across 19 studies. Mean gestational age at birth ranged between 34 and 36 weeks.

CONCLUSION

These findings corroborate the rareness of HDFN and frequently needed intrauterine transfusion with inherent risks, and most births occur at a late preterm gestational age. We identified several evidence gaps providing opportunities for future studies.

Non-Invasive Fetal K Status Prediction: 7 Years of Experience

Introduction

In the Kell blood group system, the K and k antigens are the clinically most important ones. Maternal anti-K IgG antibodies can lead to the demise of a K-positive fetus in early pregnancy. Intervention can save the fetus. Prenatal K status prediction of the fetus in early pregnancy is desirable and gives a good basis for pregnancy risk management. We present the results from 7 years of clinical experience in predicting fetal K status as well as some theoretical considerations relevant for design of the assay and evaluation of results.

Methods

Blood was collected from 43 women, all immunized against K, at a mean gestational age of 18 weeks (range 10–38). A total of 56 consecutive samples were tested. The KEL *01.01 /KEL *02 single nucleotide variant that determines K status was amplified from maternal plasma DNA by PCR without allele specificity. The PCR product was sequenced by NGS technology, and the number of sequenced KEL *01.01 and KEL *02 reads were counted. Prediction of the fetal K status was based on this count and was compared with the serologically determined K status of the newborns.

Results

All fetal K predictions were in accordance with postnatal serology where available (n = 34), using our current data analysis.

Conclusion

We have developed an NGS-based method for the non-invasive prediction of fetal K status. This approach requires special considerations in terms of primer design, stringent preanalytical sample handling, and careful analytical procedures. We analyzed samples starting at GA 10 weeks and demonstrated the correct prediction of fetal K status. This assay enables timely clinical intervention in pregnancies at risk of hemolytic disease of the fetus and newborn caused by maternal anti-K IgG antibodies.