Receipt of RhD-positive whole blood for life-threatening bleeding in female children: A survey in alloimmunized mothers regarding minimum acceptable survival benefit relative to risk of maternal alloimmunization to anti-D

BACKGROUND

Low-titer group O whole blood (LTOWB) for treatment of hemorrhagic shock sometimes necessitates transfusion of RhD-positive units due to short supply of RhD-negative LTOWB. Practitioners must choose between using RhD-positive LTOWB when RhD-negative is unavailable against the risk to a female of childbearing potential of becoming RhD-alloimmunized, risking hemolytic disease of the fetus and newborn (HDFN) in future children, or using component therapy with RhD-negative red cells. This survey asked females with a history of red blood cell (RBC) alloimmunization about their risk tolerance of RhD alloimmunization compared to the potential for improved survival following transfusion of RhD-positive blood for an injured RhD negative female child.

STUDY DESIGN AND METHODS

A survey was administered to RBC alloimmunized mothers. Respondents were eligible if they were living in the United States with at least one red cell antibody known to cause HDFN and if they had at least one RBC alloimmunized pregnancy.

RESULTS

Responses from 107 RBC alloimmmunized females were analyzed. There were 32/107 (30%) with a history of severe HDFN; 12/107 (11%) had a history of fetal or neonatal loss due to HDFN. The median (interquartile range) absolute improvement in survival at which the respondents would accept RhD-positive transfusions for a female child was 4% (1%-14%). This was not different between females with and without a history of severe or fatal HDFN (p = .08 and 0.38, respectively).

CONCLUSION

Alloimmunized mothers would accept the risk of D-alloimmunization in a RhD-negative female child for improved survival in cases of life-threatening bleeding.

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.

Passive transfer of alloantibodies through breast milk as a mediator of hemolytic anemia

BACKGROUND

Hemolytic disease of the fetus and newborn (HDFN) is characterized by destruction of fetal/neonatal red blood cells (RBCs) secondary to maternally derived antibodies, which are typically thought to be passively acquired via placental transfer. Few cases have examined the possibility of HDFN mediated by maternal antibodies passively transferred via breast milk.

METHODS

We describe two cases of persistent HDFN in infants potentially mediated by passively acquired antibodies via maternal breast milk. We discuss supporting and refuting evidence that may account for this possibility and describe testing methodology illustrating how maternal alloantibodies can be detected in breast milk.

RESULTS

In both cases, anti-D antibodies were detected in maternal breast milk. One patient experienced a significant decrease in anti-D plasma titer from 64 to 4 dilutions following 2 weeks of breastfeeding cessation. The other patient experienced a resolution of anemia without breastfeeding cessation.

CONCLUSION

There is a paucity of data regarding the lifespan of passively acquired RBC antibodies in neonatal circulation, with significant variation noted between passively acquired IgG based on studies utilizing intravenous immunoglobulin compared to studies of maternally-acquired antiviral IgG antibodies. While our data do not definitively implicate passive transfer of alloantibodies in breast milk as a mediator of HDFN, they do illustrate the need for further investigation into the mechanisms and kinetics of passively acquired antibodies in neonatal circulation.

Misclassification of RhD variants among pregnant women: a systematic review

The D antigen of the Rh blood group is considered clinically significant due to its ability to cause hemolytic transfusion reactions and hemolytic disease in the fetus and newborn. This systematic review discusses the prevalence of RhD variants among pregnant women and the importance of including RhD genotyping for prenatal testing to detect RhD variants and prevent anti-D alloimmunization. A comprehensive literature search was conducted using scientific search engines, including PubMed and MEDLINE databases, with the keywords 'anti-D alloimmunization', 'RhD variant', and 'pregnant women.' The review adhered to the PRISMA guidelines. Meta-analysis was performed using MedCalc version 20. A significance level of p≤0.05 was considered statistically significant for all two-tailed tests. The meta-analysis included four articles that met the inclusion criteria. The total prevalence of RhD positivity (RhD+) was 61% (95% CI:34%-85%). The prevalence ranged from 22% to 82%, indicating a high degree of heterogeneity between studies (I2=98.71%, p<0.0001). The overall prevalence of D variants was 15% (95% CI, 9%-23%) with a prevalence of 0.05% to 100%, showing a high degree of heterogeneity between studies (I2=99.89%, p<0.0001). Anti-D alloimmunization could occur in pregnant women with some types of RhD variants. All four studies focused on molecular testing of samples showing inconsistent or weak results with at least two anti-D antibodies using serological methods.

Anti-C causing severe hemolytic disease of the fetus and newborn: a rare case report

Hemolytic disease of the fetus and newborn (HDFN) due to anti-D was severe and fatal before the development of RhD immune prophylaxis. Proper screening and universal administration of Rh immune globulin has decreased the incidence of HDFN to a great extent. Pregnancy, transfusion, and transplantation still increase the chances of other alloantibody formation and the potential for HDFN. Advanced methods for immunohematology investigation allow for the identification of alloantibodies causative for HDFN other than anti-D. Many antibodies have been reported to cause HDFN, but there is scant literature where isolated anti-C is responsible for HDFN. We present here a case of severe HDFN caused by anti-C leading to severe hydrops and death of the neonate despite three intrauterine transfusions and other measures.

Maternal Cold-Reacting Immunoglobulin G Anti-M of MNS Blood Group System Causing Hemolytic Disease of the Fetus

Several cases of the hemolytic disease of the fetus and newborn (HDFN) caused by immunoglobulin G (IgG) anti-M antibodies have been reported, in which almost all the HDFN-associated anti-M were warmly reacting. Here we report two cases of severe HDFN associated with cold-reacting IgG anti-M. In both cases, pregnancy was terminated, in weeks 33 and 23 respectively, due to a diagnosis of fetal growth retardation (FGR). To our knowledge, these are the most severe HDFN cases caused by cold-reacting IgG anti-M.

Serologic reactivity of unidentified specificity in antenatal testing and hemolytic disease of the fetus and newborn: The BEST collaborative study

BACKGROUND

The clinical significance of serologic reactivity of unidentified specificity (SRUS) in pregnancy is not clear based on available literature. The aim of this study is to determine if SRUS is associated with hemolytic disease of the fetus and newborn (HDFN).

STUDY DESIGN AND METHODS

Retrospective data were collected from eight institutions over an 11-year study period (2010-2020), when available (5/8 sites). The outcome of the pregnancies with SRUS-no, mild, moderate, or severe HDFN-was determined.

RESULTS

SRUS was demonstrated in 589 pregnancies. After excluding those with incomplete data, a total of 284 pregnancies were included in the primary HDFN outcome analysis. SRUS was detected in 124 (44%) pregnancies in isolation, and none were affected by HDFN. Of 41 pregnancies with SRUS and ABO incompatibility, 37 (90%) were unaffected, and 4 (10%) were associated with mild HDFN. Of 98 pregnancies with SRUS and concurrent identifiable antibody reactivity(s), 80 (81%) were unaffected, and 19 (19%) were associated with mild to severe HDFN. There was 1 case of mild HDFN and 1 case of severe HDFN in the 21 pregnancies with SRUS, ABO incompatibility, and concurrent identifiable antibody reactivity(s), and 19 (90%) were unaffected by HDFN. Among all patients with repeat testing, newly identified alloantibodies or other antibodies were identified in 63 of 212 (30%) patients. Although most were not clinically significant, on occasion SRUS preceded clinically significant antibody(s) associated with HDFN (3%, 5/188).

CONCLUSION

The antenatal serologic finding of SRUS in isolation is not associated with HDFN but may precede clinically significant antibodies.

Hemolytic disease of the fetus and newborn in the sensitizing pregnancy where anti-D was incorrectly identified as RhIG

Background

Hemolytic disease of the fetus and newborn (HDFN) is a potentially fatal complication in Rh‐incompatible pregnancies and rarely occurs in the sensitizing pregnancy. Distinguishing RhIG from true anti‐D identified is challenging. A case of severe HDFN in which a sample drawn at 28 weeks showed anti‐D antibody (3+ strength) attributed to RhIG is described. RBC antibody testing early in pregnancy was negative. At birth, the infant was severely anemic and maternal anti‐D titer was 1:256. This case represents a clinically significant anti‐D in the sensitizing pregnancy that was missed due to confusion with RhIG.

Methods

To determine if agglutination strength could be helpful, a retrospective chart‐review using both electronic and paper medical records was performed on 348 samples identified as RhIG and 52 true anti‐D samples. The agglutination strength of antibody was recorded for each sample.

Results

For RhIG, there was an even distribution between the weak to moderate agglutination strength (w+, 1+, and 2+) results (35%, 26%, and 33%, respectively) and just 6% had a 3+ strength. Agglutination strength in patients with high titer (≥1:16) anti‐D showed they often (44.4%) have 1+ or 2+ agglutination reactivity.

Conclusions

These results show that agglutination strength alone does not provide reliable evidence to distinguish RhIG from high titer anti‐D antibodies. We recommend that in cases where there is any uncertainty about whether the anti‐D reactivity is due to RhIG, titers should be performed to rule out clinically significant anti‐D antibody.

Recommendation for validation and quality assurance of non-invasive prenatal testing for foetal blood groups and implications for IVD risk classification according to EU regulations

BACKGROUND AND OBJECTIVES

Non-invasive assays for predicting foetal blood group status in pregnancy serve as valuable clinical tools in the management of pregnancies at risk of detrimental consequences due to blood group antigen incompatibility. To secure clinical applicability, assays for non-invasive prenatal testing of foetal blood groups need to follow strict rules for validation and quality assurance. Here, we present a multi-national position paper with specific recommendations for validation and quality assurance for such assays and discuss their risk classification according to EU regulations.

MATERIALS AND METHODS

We reviewed the literature covering validation for in-vitro diagnostic (IVD) assays in general and for non-invasive foetal RHD genotyping in particular. Recommendations were based on the result of discussions between co-authors.

RESULTS

In relation to Annex VIII of the In-Vitro-Diagnostic Medical Device Regulation 2017/746 of the European Parliament and the Council, assays for non-invasive prenatal testing of foetal blood groups are risk class D devices. In our opinion, screening for targeted anti-D prophylaxis for non-immunized RhD negative women should be placed under risk class C. To ensure high quality of non-invasive foetal blood group assays within and beyond the European Union, we present specific recommendations for validation and quality assurance in terms of analytical detection limit, range and linearity, precision, robustness, pre-analytics and use of controls in routine testing. With respect to immunized women, different requirements for validation and IVD risk classification are discussed.

CONCLUSION

These recommendations should be followed to ensure appropriate assay performance and applicability for clinical use of both commercial and in-house assays.

Breast milk contains red cell isohaemagglutinins: An observational study of 176 mothers

BACKGROUND AND OBJECTIVES

Maternal antibodies are transferred to the child, predominantly IgG, via the transplacental route, and mostly IgA through breast milk. Cases reported by us and others have shown the transfer of red cell allo-antibodies through breast milk. This study was conducted to assess the presence of isohaemagglutinins in breast milk, the range of titres, and the correlation between breast milk and maternal plasma titres.

MATERIALS AND METHODS

A total of 176 mothers were recruited in this study. Breast milk was collected after sufficient feeding was established and within 2-5 days of delivery in a sterile container without any anticoagulant. Antibody screen, identification and titres were performed on maternal plasma as well as breast milk.

RESULTS

Anti-A and anti-B in breast milk corresponding to their respective maternal blood groups were found in all the samples. This study has shown titres in the breast milk of anti-A and anti-B ranging from 2 to 1024 in both saline and Coombs phases. There was no association between plasma and breast milk titres, thus making it impossible to predict which mother may potentially transfer a larger amount of these haemagglutinins. Isotypes of anti-A and anti-B were evaluated in both plasma and breast milk of 11 samples, which showed predominantly IgG in 7 (63.63%) and predominantly IgA in 4 (36.36%) samples.

CONCLUSION

Our study demonstrates the presence of a wide range of titres for IgG antibodies of the ABO blood group system in breast milk. The clinical impact of this finding needs to be studied further, as it assumes great relevance in developing countries where anaemia continues to challenge young infants.

Estimating the risks of prehospital transfusion of D-positive whole blood to trauma patients who are bleeding in England

Background and Objectives

D‐negative red cells are transfused to D‐negative females of childbearing potential (CBP) to prevent haemolytic disease of the foetus and newborn (HDFN). Transfusion of low‐titre group O whole blood (LTOWB) prehospital is gaining interest, to potentially improve clinical outcomes and for logistical benefits compared to standard of care. Enhanced donor selection requirements and reduced shelf‐life of LTOWB compared to red cells makes the provision of this product challenging.

Materials and Methods

A universal policy change to the use of D‐positive LTOWB across England was modelled in terms of risk of three specific harms occurring: risk of haemolytic transfusion reaction now or in the future, and the risk of HDFN in future pregnancies for all recipients or D‐negative females of CBP.

Results

The risk of any of the three harms occurring for all recipients was 1:14 × 10³ transfusions (credibility interval [CI] 56 × 10²–42 × 10³) while for females of CBP it was 1:520 transfusions (CI 250–1700). The latter was dominated by HDFN risk, which would be expected to occur once every 5.7 years (CI 2.6–22.5). We estimated that a survival benefit of ≥1% using LTOWB would result in more life‐years gained than lost if D‐positive units were transfused exclusively. These risks would be lower, if D‐positive blood were only transfused when D‐negative units are unavailable.

Conclusion

These data suggest that the risk of transfusing RhD‐positive blood is low in the prehospital setting and must be balanced against its potential benefits.

Perception of risk in massive transfusion as it relates to fetal outcomes: A survey of surgeons and nurses at one American trauma center

BACKGROUND

The use of blood products early in the resuscitation of bleeding trauma patients is widely accepted, but made difficult by limited supplies of D- red blood cell (RBC)-containing products. Use of D+ RBC-containing products would alleviate this issue, but could lead to alloimmunization. Risk associated with transfusing D+ RBC in emergency bleeding situations is being reconsidered. The level of concern surrounding emergency transfusion as it relates to future fetal harm was surveyed among surgeons and nurses.

METHODS

Faculty and staff in the Departments of Surgery and Nursing were surveyed on the risks of receiving an emergency RBC transfusion and the subsequent potential for fetal harm. Answers were grouped as likely to accept (likely/very likely) or refuse transfusion (unlikely/very unlikely). Participants were compared by sex, and women by child-bearing age, ([15-50 years] vs. [>50 years]).

RESULTS

Ninety surveys were initiated with 76 fully completed. Male (n = 39) and female (n = 37) respondents were comparable. Most female respondents (30/37, 81%) were of childbearing age. Overall, both males (38/39, 95%) and females (33/37, 89%; p = .19) were likely to accept a transfusion in an emergency. There was no difference in transfusion acceptance if the risk of fetal harm was presented as 1% (p = .73) or 0.1% (p = .51). Most females (34/37, 92%) were not opposed to transfusion even if there was an unspecified risk of future fetal harm.

CONCLUSION

Most of the surgeons and nurses who responded would accept a transfusion in an emergency situation even if it might lead to harming a future fetus.

From A to AB: A Caucasian Mother with High Anti-B Titer Causing Hemolytic Disease of the Newborn

We report on a term infant with clinically significant hemolysis and hyperbilirubinemia. Testing revealed ABO incompatibility between maternal type A and infant type AB. The maternal alloantibody screen was negative. The infant's direct antiglobulin test was positive, and anti-B IgG was eluted off the infant's red blood cells (RBCs). Testing of the mother's plasma revealed a high anti-B titer. The infant was successfully treated with phototherapy and intravenous immunoglobulin. The bilirubin and hematocrit stabilized, and the infant was discharged home. This case was unusual because of its severity and unusual ABO constellation. Furthermore, this report is an exemplary educational case study on how effective collaboration between the clinical team and the blood bank laboratory is critical in reaching the correct diagnosis. In summary, the differential diagnosis of more unusual and atypical ABO-incompatible constellations must be considered when an infant presents with unexplained hemolysis.

The effect of extended c, E and K matching in females under 45 years of age on the incidence of transfusion-induced red blood cell alloimmunisation

Maternal alloantibodies directed against fetal red blood cell (RBC) antigens may cause potentially life‐threatening haemolytic disease of the fetus and newborn (HDFN). Dutch transfusion guidelines therefore prescribe preventive cEK matching for all (pre‐)fertile females. To quantify the impact of cEK matching, we compared overall and antigen‐specific cumulative RBC alloimmunisation incidences in females and males aged <45 years. Among a multicentre cohort comprised of patients who received their first and subsequent RBC unit between 2005 and 2019, first‐formed RBC alloantibodies were detected in 47 of 2998 (1·6%) females and 49 of 2507 (2·0%) males. Comparing females and males, overall alloimmunisation incidences were comparable (3·1% [95% confidence interval (CI) 2·1–4·4] versus 3·5% (95% CI 2·4–4·9, P = 0·853) after 10 units transfused). However, cEK alloimmunisation incidences were significantly lower among females (0·6% (95% CI 0·3–1.5) versus 2·2% (95% CI 1·5–3·4, P = 0·001) after 10 units transfused). Yet, despite cEK‐matching guidelines being in effect, 6·5%, 3·6% and 0·2% of all RBC units remained mismatched for c, E or K antigens respectively. Most of these mismatches were almost always due to emergency settings. Even though cEK alloimmunisation was not prevented completely, implementation of cEK matching resulted in an alloantigen‐exposure risk reduction of up to 98%.

Hyporegenerative anemia in anti-M-associated hemolytic disease of the fetus

BACKGROUND

The anti-M antibody can lead to hemolytic disease of the fetus and newborn (HDFN) and adverse fetal outcomes, especially in the Asian population. However, fetal erythropoiesis resulting from M alloimmunization needs further investigation.

STUDY DESIGN AND METHODS

We analyzed erythropoiesis in eight fetuses with M alloimmunization and compared them with the fetuses affected by anti-D. They were matched as pairs according to the gestational age of diagnosis and the hematocrit before treatment. Paired t-tests or paired Wilcoxon rank-sum tests were conducted to compare the difference in the cord blood indexes. Pearson correlation analysis was used to evaluate the correlativity between hematocrit and the reticulocyte percentage in the two groups.

RESULTS

The fetuses in the MN group had lower reticulocyte count and percentage than those in the RhD group (p < .05). All of the fetal reticulocyte production indexes (RPIs) in the MN group were less than 2, indicating an inadequate hemopoietic response to anemia, while the majority of the RPIs in the RhD group (85.7%) were significantly higher (p = .003), with 6 cases greater than 2.5. Hematocrit was negatively correlated with reticulocyte percentage (y = 54.7-171.7x, r²  = 0.825, p = .005) in the RhD group, while no significant correlation was found in the MN group. No difference in the number of IUT, interval, or the fetal outcome was found between the two groups.

CONCLUSION

Fetal reticulocytopenia provided direct evidence of an inadequate hemopoietic response in HDFN due to anti-M, leading to hyporegenerative anemia. Once the IgG component of anti-M is detected, close monitoring should be considered.

Anti-S Antibody: A Rare Cause of Fetal Hydrops in a Previously Sensitized Mother

Anti-S is an IgG antibody and a rare cause of hemolytic disease of the fetus and newborn. A 38 year old woman with blood group O Rh-positive presented to the hospital at 30 weeks gestation. Her past medical history was significant for sickle cell disease and alloantibodies against the Fya, Jkb, and S antigens. Obstetric ultrasound showed the fetus to have developed scalp edema, cardiomegaly, small pericardial effusion, and large ascites. Periumbilical blood sampling results showed the fetus blood type as blood group O Rh-positive with anti-S and hemoglobin of 2 gm/dL. After multiple intrauterine transfusions of red blood cells, the fetal hemoglobin increased to 12.9 g/dL. Anti-S can cause fetal hydrops, although it is rare. All pregnant women with anti-S should be closely monitored and treated during pregnancy for the possibility of developing a severe hemolytic disease of the fetus and newborn.

Evaluating automated titre score as an alternative to continuous flow analysis for the prediction of passive anti-D in pregnancy

OBJECTIVES

To evaluate the potential of the automated titre score (TS) as an alternative method to continuous flow analysis (CFA) for the prediction of the nature of anti-D in pregnancy.

BACKGROUND

The 2016 revised British Society for Haematology (BSH) antenatal guidelines recommended a measurement of anti-D concentration by CFA to ensure the detection of potential immune anti-D. Due to high referral costs and resource pressures, uptake has been challenging for hospital laboratories. Serious Hazards of transfusion (SHOT) data have previously shown that this has contributed to missed antenatal follow ups for women with immune anti-D and neonates affected by haemolytic disease of the fetus/newborn.

METHODS/MATERIALS

In this multicentre comparative study, samples referred for CFA quantification were also tested by an ORTHO VISION automated anti-D indirect antiglobulin test (IAT) serial dilution and then converted to TS. CFA results and history of anti-D prophylaxis were used to categorise samples as passive or immune, with the aim of determining a potential TS cut-off for CFA referral of at risk patients.

RESULTS

Five UK National Health Service (NHS) trusts generated a total of 196 anti-D TS results, of which 128 were classified as passive and 68 as immune. Diagnostic testing of CFA and TS values indicated a TS cut-off of 35 to assist in distinguishing the nature of anti-D. Using this cut-off, 175 (89%) results were correctly assigned into the passive or immune range, giving a specificity of 92.19% and a negative predictive value of 91.47%.

CONCLUSION

TS in conjunction with clinical and anti-D prophylaxis history can be used as a viable and cost-effective alternative to CFA in a hospital laboratory setting.

Hemolytic disease of the fetus and newborn caused by anti-Hr0 in a 27-year-old female with Dc- phenotype: A case report

Anti-Hr₀ (Anti-Rh17) is a rare immune Immunoglobulin G (IgG) to high-frequency Rh antigens that may cause severe and often fatal Hemolytic disease of the fetus and newborn (HDFN) in D--, Dc- and DC^w- mothers who have been exposed to red cells of the common Rh phenotype by transfusion or pregnancy. Several pregnant women have been affected by this antibody leading to perinatal death. Therefore, immediate and effective management of these cases is of great importance. We report a case of HDFN in a 27-year-old (G5, P3, L1), woman with Rh Dc- phenotype managed successfully using intravenous immunoglobulin (IVIg) and simple transfusions.

Do red cell alloantibodies continue to challenge breast fed babies?

BACKGROUND

Newborns have limited specific immune capability at birth, owing to delayed and constrained development of adaptive immunity. To supplement this period the mother passively transfers antibodies to the child either transplacentally or through breast milk. When maternal alloimmunisation occurs through foreign or fetal red cell surface antigens, stimulating the production of immunoglobulin G (IgG) antibodies, these IgG antibodies can cross the placenta and cause haemolytic disease of the fetus and the newborn.

OBJECTIVE

We present two case reports of a neonate and an infant in whom IgG red cell alloantibodies were transferred through maternal breast milk.

METHODS

Maternal serum, baby's serum and expressed breast milk samples were tested for the presence of red cell alloantibodies using gel card. Antibody screening, antibody identifications and titres alongside monospecific direct antiglobulin test, IgG subtypes were performed using the standard methods.

RESULTS

In the first case, a 6-month-old child was incidentally found to have positive antibody screen. Anti-KELL1 was identified, which was also present in maternal serum and breast milk. The second neonate was evaluated for haemolysis and was found to have anti-D. Anti-D was also detected in the maternal serum and breast milk. Both babies did not have any sensitising events. The first baby was asymptomatic, but the second baby had ongoing haemolysis until 1 month.

CONCLUSION

We report that maternal anti-KELL1 and anti-D antibodies were present in breast milk and were capable of being transferred to a feeding child. Our case report also raises interesting and unanswered immunologic fundamentals that should be considered in neonates with unexplained anaemia or delayed and persistent haemolysis.

Resolving Blocked Antigen Phenomenon in Hemolytic Disease of the Fetus and Newborn Due to Anti-K

High-titer antibodies are a cause of false-negative reactions in red blood cell antigen phenotyping, an event referred to as blocked antigen phenomenon (BAP). In hemolytic disease of the fetus and newborn, BAP complicates laboratory workups as fetal phenotype is helpful in confirming the responsible antibody. Acid elution techniques, techniques using ethylenediaminetetraacetic glycine acid, as well as those using chloroquine diphosphate have been used to resolve BAP; however, ethylenediaminetetraacetic glycine acid destroys K-antigen expression and chloroquine diphosphate is not always effective. We report a case of severe hemolytic disease of the fetus and newborn from anti-K where a modified gentle heat elution resolved BAP. Although infrequently considered with isolated reports in the literature, heat elution is simple, is effective, and involves readily available materials in most blood banks.

The unusual abundance of a rare finding!

We present images (Figure 1A-D) of a preterm girl who had severe anemia due to HDFN caused by maternal anti-C and anti-D alloantibodies. These images show erythrophagocytosis, which is a very interesting and rarely encountered feature. We believe that physicians taking care of such patients should be more aware of this characteristic yet under-detected finding.

Predicting anaemia and transfusion dependency in severe alloimmune haemolytic disease of the fetus and newborn in the first 3 months after birth

Infants with haemolytic disease of the fetus and newborn (HDFN) often require erythrocyte transfusions in the first 3 months of life. We aimed to evaluate the incidence, timing and potential predictors of transfusion-dependent anaemia. An observational cohort of 298 term and near-term infants with severe HDFN treated with or without intrauterine transfusion (IUT) was evaluated. Transfusions were administered to 88% (169/193) of infants with IUT and 60% (63/105) without IUT. The following potential predictors were associated with less anaemia: K compared to D immunisation [odds ratio (OR) 0·13, 95% confidence interval (CI): 0·03-0·55], higher reticulocyte count at birth [per 10 parts per thousand (‰) higher, OR 0·99, CI: 0·97-1·00] and exchange transfusion (OR 0·11, 95% CI: 0·03-0·50). Without IUT, these variables were: lower reticulocyte count at birth (per 10‰ lower, OR 1·02, 95% CI: 1·00-1·03), lower maximum bilirubin after birth (per 10 μmol/l lower, OR 1·01, 95% CI: 1·01-1·02) and exchange transfusion (OR 0·07, 95% CI: 0·01-0·20). In conclusion, potential predictors for anaemia in infants with severe HDFN varied between infants treated with and without IUT and are useful for selecting subgroups of infants at increased risk of anaemia.

Red Blood Cell Alloimmunization in the Pregnant Patient

Alloimmunization to red blood cell (RBC) antigens represents a challenge for physicians caring for women of child bearing potential. Exposure to non-self RBC antigens may occur during transfusion or pregnancy leading to the development of antibodies. If a subsequent fetus bears that antigen, maternal antibodies may attack the fetal red blood cells causing red cell destruction and clinically significant hemolytic disease of the fetus and newborn (HDFN). In the most severe cases, HDFN may result in intrauterine fetal demise due to high output cardiac failure, effusions and ascites, known as "hydrops fetalis". This article reviews strategies for management and prevention of RBC alloimmunization in women of child bearing potential.

Molecular characterization and multidisciplinary management of Gerbich hemolytic disease of the newborn

Gerbich (Ge) antigens are high frequency red cell antigens expressed on glycophorin C (GYPC) and glycophorin D. Hemolytic disease of the fetus and newborn (HDFN) due to Gerbich antibody is rare and presents a clinical challenge, as Gerbich negative blood is scarce. We report a case of HDFN due to maternal Ge3 negative phenotype and anti-Ge3 alloimmunization, successfully managed by transfusion of maternal blood. Molecular testing revealed that the mother has homozygous deletion of exon 3 of GYPC, the father is homozygous wildtype for GYPC, and the infant is obligate heterozygote expressing Ge3.

A Case of a Newborn With Blocked RhD Antigen and HDFN

A group O RhD-negative pregnant patient with anti-D antibody at titer 1:2048 delivered a baby boy by cesarean section at 38 + 6 weeks gestational age. The neonate typed as group O, but D antigen was at first uncertain. DAT and antibody screen of newborn were both positive. Various assays were used for D antigen determination. Ultimately, D antigen blocked by high-titer maternal anti-D antibody was confirmed. Total bilirubin of the newborn was 52.7 umol/L, and hemoglobin was 1.46 mg/dL. O RhD-negative red cells were used for an exchange transfusion.

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.

Anti-D Antibodies in Pregnant D Variant Antigen Carriers Initially Typed as RhD

BACKGROUND

To evaluate the incidence, the consequences, and the prevention strategy of anti-D alloimmunizations of D variant carriers in the obstetric population of Split-Dalmatia County, Croatia.

METHODS

RhD immunization events were evaluated retrospectively for the period between 1993 and 2012. Women were tested for RhD antigen and irregular antibodies. Those with anti-D antibody who were not serologically D- were genotyped for RHD. They were evaluated for their obstetric and transfusion history and their titer of anti-D. The neonates were evaluated for RhD status, direct antiglobulin test (DAT), hemoglobin and bilirubin levels, transfusion therapy as well as phototherapy and outcome.

RESULTS

Out of 104,884 live births 102,982 women were tested for RhD antigen. Anti-D immunization occurred in 184 women which accounts for 0.9% of individuals at risk of anti-D formation. 181 cases occurred in women serologically typed as D-. Three women were partial D carriers (DVa n = 2, DNB n = 1), initially typed RhD+, and recognized as D variant carriers after the immunization occurred. Anti-D titer varied from 1:1 to 1:16. Six children were RhD+, four had positive DAT, and two underwent phototherapy.

CONCLUSION

Anti-D immunization occurred in pregnant partial D carriers (DVa, DNB). RhD+ children had serologic markers of hemolytic disease of the fetus and newborn (HDFN), with no cases of severe HDFN.

Prevalence, Specificity and Titration of Red Cell Alloantibodies in Multiparous Antenatal Females at a Tertiary Care Centre from North India

Screening and detection of clinically significant antibodies among antenatal women plays an important role in transfusion safety and preventing hemolytic disease of fetus and newborn. Routine screening of antenatal women for antibodies is not done in all blood centres of our country and so immunization rates are not known in pregnant women. We studied the prevalence of alloantibodies and titration of Anti D among antenatal multiparous women in Jammu region. In present prospective study, 750 antenatal multiparous women attending antenatal clinics were typed for ABO and D antigens. Alloantibody screening was done, if positive, specificity of alloantibody was ascertained by using commercially available red cell panel by tube method. Rate of alloimmunization was correlated with Rh D status, gravida, previous transfusion history and bad obstetric history. Titration of alloantibody D was done in first and third trimester of pregnancy. In present study most common blood group detected was B positive (38.4 %). Rh D negative cases constituted 7.6 % of total cases. Rate of alloimmunization was 2 %. A significant correlation was seen between Rh D-negative and alloimmunization (21 % in D-negative and 0.45 % in D-positive). There is significant increasing degree of alloimmunization with increase in Gravida. Alloimmunization in females with bad obstetric history was high (4.41 %) as compared to females with no bad obstetric history showing only 1.76 %. Alloantibodies detected were Anti-D, Anti-E, Anti-C and Anti-K. Anti-D constituted 80 % of all alloantibodies detected. Six women in their third trimester had raised titers of anti-D. Most common alloantibody detected was anti-D (80 %). Alloantibodies to other Rh antigens and Kell blood group systems were also identified. To minimize alloimmunization in Rh D negative women, proper Anti D immunoprophylaxis should be implemented.

Management of a pregnant woman with anti-holley alloantibody

BACKGROUND

Holley (Hy) is a high-incidence antigen of the Dombrock blood group system (ISBT 014), present in almost 100% of most populations and more than 99% of Blacks. Since anti-Hy is an extremely rare antibody, data on its clinical relevance and in particular on a possible hemolytic disease of the fetus and newborn (HDFN) are scarce.

CASE REPORT

The pregnant patient underwent two autologous whole blood collections at weeks 17 and 19 of gestation with cryopreservation. In our case autologous whole blood collection was well tolerated. There were no signs of HDFN in the healthy newborn.

CONCLUSION

Our case improves our understanding of anti-Hy alloantibodies during pregnancy. Additionally, autologous whole blood collection of RBC units with cryopreservation is a safe and feasible way to manage pregnancies in women with rare alloantibodies, when no compatible donor can be found.

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.

Frequencies of maternal red blood cell alloantibodies in Port Harcourt, Nigeria

BACKGROUND

Alloantibodies of clinical importance can cause transfusion reactions or hemolytic disease of the fetus and newborn (HDFN). The frequencies of these antibodies have not been reported in our locality.

AIMS

To determine the frequency of occurrence of alloantibodies among pregnant women in Port Harcourt, Nigeria.

SETTINGS AND DESIGN

This is a prospective study, which was carried out in the Braithwaite Memorial Specialist Hospital, Port Harcourt, Nigeria.

MATERIALS AND METHODS

Screening and identification of red blood cell alloantibodies was done on the sera of 500 pregnant women using the DiaMed, DiaCell, and DiaPanel reagents (Cressier, Switzerland). ABO and Rh blood groups were done using antisera bought from Biotec (Ipswich, UK).

RESULTS

Alloantibodies were identified in the serum of 17 of the 500 (3.4%) pregnant women. The specificity of the antibodies was as follows: anti-C 6 (1.2%), anti-E 3 (0.6%), anti-Jsb 3 (0.6%), and anti-K 5 (1.0%). No anti-D was identified despite 8.6% of the study population being Rhesus D (Rh D) negative. The distribution of the antibodies was found to be independent of the blood groups of the participants (χ(2) = 4.050, P = 0.670). Blood group O constituted the highest percentage (48.0%).

CONCLUSION

This study has identified the presence of non-Rh D antibodies to the proportion of 3.4%. Rh D antibody was absent in this population irrespective of the relatively high percentage of Rh D negative women. There is a need to determine the actual risk these antibodies may pose to the antenatal women and to include antibody screening and identification in routine antenatal care.