Management of Pregnancies Complicated by Anti-E Alloimmunization

Alloimmune hemolytic disease of the fetus and newborn: genetics, structure, and function of the commonly involved erythrocyte antigens

Hemolytic disease of the fetus and newborn (HDFN) can occur when a pregnant woman has antibody directed against an erythrocyte surface antigen expressed by her fetus. This alloimmune disorder is restricted to situations where transplacental transfer of maternal antibody to the fetus occurs, and binds to fetal erythrocytes, and significantly shortens the red cell lifespan. The pathogenesis of HDFN involves maternal sensitization to erythrocyte "non-self" antigens (those she does not express). Exposure of a woman to a non-self-erythrocyte antigen principally occurs through either a blood transfusion or a pregnancy where paternally derived erythrocyte antigens, expressed by her fetus, enter her circulation, and are immunologically recognized as foreign. This review focuses on the genetics, structure, and function of the erythrocyte antigens that are most frequently involved in the pathogenesis of alloimmune HDFN. By providing this information we aim to convey useful insights to clinicians caring for patients with this condition.

Comparison of automated solid phase versus manual saline indirect antiglobulin test methodology for non-ABO antibody titration: Implications for perinatal antibody monitoring

BACKGROUND

Accurate antibody titration is crucial in prenatal evaluations to identify patients who need clinical monitoring for hemolytic disease of the fetus and newborn (HDFN) causing fetal anemia. This study compares the established gold standard method of manual tube saline indirect antiglobulin testing (SIAT) with the newer automated solid phase (ASP) method of antibody titration and aims to establish the critical titer threshold for ASP that corresponds to the previously established SIAT critical threshold of ≥16 used in our laboratory.

STUDY DESIGN AND METHODS

One hundred fifty-seven prenatal and donor plasma samples with known antibodies were tested using both SIAT and ASP methodologies and results were compared.

RESULTS

The study found that ASP titers were, on average, 1.33 dilutions higher than SIAT titers. The critical titer cutoff for ASP was determined to be ≥32, which is one tube higher than the SIAT cutoff of ≥16.

DISCUSSION

The ASP method for antibody titration offers greater reproducibility and efficiency compared with manual SIAT titration. This study suggests that a titer cutoff of ≥32 is appropriate for most clinically significant antibodies using ASP. However, further research is needed to determine the comparability of ASP with SIAT in samples with multiple antibodies, anti-M antibodies, and other less common antibodies. Validation of the ASP titer cutoff against HDFN clinical outcomes is required before implementing this test for routine use in perinatal antibody titration.

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.

A cross-sectional study of haemolytic disease of the newborn in Uganda

BACKGROUND AND OBJECTIVES

Haemolytic disease of the newborn (HDN) is an immune haemolytic anaemia from maternal alloantibodies. Rh immunoglobulin (RhIg) prophylaxis can prevent alloimmunization to the D antigen. However, RhIg is not universally available in Uganda. ABO incompatibility also causes HDN. We determined the prevalence of HDN among newborn infants with jaundice in Uganda.

MATERIALS AND METHODS

We conducted a prospective cross-sectional study at Kawempe National Referral Hospital, Kampala, Uganda. Infants aged 0-14 days with neonatal jaundice (or total bilirubin >50 μmol/L) were enrolled. Clinical evaluation and laboratory testing, including ABO, RhD typing and maternal antibody screen, were performed.

RESULTS

A total of 466 babies were enrolled. The mean (SD) age was 3.4 (1.5) days. Of newborn babies with jaundice, 17.2% (80/466) had HDN. Babies with HDN had lower haemoglobin (SD); 15.7 (2.7) compared with those without HDN; 16.4 (2.4) g/dL, p = 0.016; and a higher bilirubin (interquartile range); 241 (200-318) compared with those without HDN; 219 (191-263) μmol/L, p < 0.001. One baby had anti-D HDN, while 46/466 had HDN from an ABO incompatibility (anti-A 43.5% and anti-B 56.5%); 82% of babies with HDN also had suspected neonatal sepsis or birth asphyxia. About 79.2% (57/72) of mothers did not have ABO/Rh blood group performed antenatally. All infants with HDN survived except one.

CONCLUSION

Among newborn infants with jaundice, HDN is not rare. The majority is due to ABO HDN affecting group A and group B babies equally. Ensuring routine ABO/Rh grouping for all pregnant women is an area for improvement.

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.

Successful treatment of COVID-19-related acute respiratory distress syndrome with a rare blood type: A case report

Extracorporeal membrane oxygenation is indispensable for critically severe COVID-19 patients. However, it would be inapplicable to patients with a rare blood type or blood transfusion refusal. In that case, severely conservative fluid management with the sacrifice of renal functions and hydrocortisone therapy should be considered for better oxygenation.

Hemolytic Disease of Fetus and Newborn in a Primigravida with Multiple Alloantibodies Involving Anti-Jka and Anti-E: A Case Report

The majority of hemolytic disease of the fetus and newborn (HDFN) reported in the literature is due to ABO and rhesus incompatibility. However, there are also other minor blood groups that have been identified as a cause of HDFN, although the occurrence is much rarer. The antibody screening program for D negative mother and the anti-D immunoglobulin treatment showed a significant reduction of the occurrence of HDFN secondary to anti-D. In a developed country, the screening for red blood cell antibody in the pregnant mother other than anti-D reduced the possibility of HDFN occurrence hence reduced the fetal morbidity and subsequently increased the fetal well being during pregnancy and after the postnatal period. In this case report, we discuss HDFN in a primigravida patient secondary to multiple alloantibodies (anti-Jka and anti-E). The baby developed jaundice with bilirubin levels approaching the exchange transfusion level. However, with extensive phototherapy and immunoglobulin treatment, the child did not require exchange transfusion. We also included the importance of the routine antenatal antibody screening program. This practice will help the transfusion center to find the antigen negative blood in a timely manner and reduce the morbidities and mortalities of HDFN among the newborns.

Hemolytic disease of the fetus and newborn due to multiple alloantibodies in pregnancy

Immune hemolytic disease of the fetus and newborn is a condition in which there is the premature destruction of fetal or neonatal red cells due to maternal alloantibody against red cell antigen inherited from father. We report the case of Hemolytic disease of fetus and newborn (HDFN) due to anti-E and anti-Fya antibody. Blood grouping was done using the conventional tube technique. Rh and Kell phenotyping of the patient and her husband performed by column agglutination and Duffy phenotyping were done by the conventional tube technique. Direct antiglobulin test was performed by column agglutination technique. Antibody screening and identification were done. Anti-E and Anti-Fya were identified with titer of Anti-E: 1:64 and Anti-Fy^a: 1:256. The patient's neonate developed jaundice. Phototherapy was given. Bilirubin stabilized and discharged on the 12^th day.

Diagnostic value of laboratory monitoring to predict severe hemolytic disease of the fetus and newborn in non-D and non-K-alloimmunized pregnancies

BACKGROUND

Pregnant women are routinely screened for red blood cell (RBC) antibodies early in pregnancy. If RBC-alloantibodies are detected, repeated laboratory testing is advised to timely identify pregnancies at high risk for severe hemolytic disease of the fetus and newborn (HDFN). We assessed for RBC alloantibodies, other than anti-D or anti-K, cut-offs for the titer and the antibody dependent cellular cytotoxicity (ADCC) test to select high-risk cases. To advise on test repeat intervals, and to avoid unnecessary testing, we evaluated the chance for exceeding the cut-offs for Rh antibodies other than anti-D, Jk, Fy, and S/s antibodies.

STUDY DESIGN AND METHODS

Diagnostic value of antibody titer and ADCC test was determined with data from a prospective index-cohort study, conducted in 2002-2004. Laboratory test outcomes were from a recent observational cohort (2015-2016).

RESULTS

A titer cut-off of ≥16 showed a sensitivity of 100% (95% CI:73-100%) and a positive predictive value (PPV) of 17% (95% CI:14%-20%). The percentage of pregnancies reaching a titer above the cut-off of ≥16 varied from 0% for anti-Jk^a /Jk^b (n = 38) to 36% for anti-c (n = 97). The ADCC test showed no cut-off with a 100% sensitivity. However, in cases with a titer ≥16 and an ADCC test ≥30% a PPV of 38% was obtained to detect severe HDFN.

CONCLUSION

A titer cut-off of ≥16 is adequate to detect all cases at risk for severe HDFN; the ADCC test may add a more accurate risk estimation. Repeated testing is recommended in pregnancies with anti-c. In pregnancies with other Rh antibodies a repeated test in the third trimester is recommended.

Haemolytic disease of the fetus and newborn diagnosed after delivery of a baby to a mother with low anti-E antibody titres

The authors report a term male neonate who was born in unexpectedly poor condition with low Apgar scores and low venous cord gas pH. He required admission to the neonatal unit and was found to have developed haemolytic anaemia with associated hydrops, following a presumed severe antenatal insult. Antenatally, low levels of anti-E antibodies (titre 8) had been detected at 28 weeks' gestation. Following the British Society for Haematology and local neonatal team guidance, advice was given for cord direct antiglobulin test, full blood count and bilirubin at delivery. This case highlights the rare case of haemolytic disease of the fetus and newborn on a background of maternal low titre anti-E antibodies.

Hydrops Fetalis and Persistent Pulmonary Hypertension in a Neonate with Anti-E Alloimmunization

Anti-E alloimmunization is the third most common cause of neonatal hemolytic disease, typically causing mild to moderate hemolytic anemia. We report an unusual case of severe hydrops fetalis and persistent pulmonary hypertension (PPHN) in a neonate with anti-E alloimmunization. Our case emphasizes the importance of close surveillance for development of severe fetal hemolytic anemia and possible need for antenatal intervention. These neonates may also need vigilant monitoring for PPHN.

How clinically important are non-D Rh antibodies?

INTRODUCTION

The advent of RhD immunoglobulin prophylaxis to prevent maternal RhD alloimmunization has reduced the incidence of this condition and its associated poor outcomes. Consequently, non-D Rh antibodies now account for a greater proportion of alloimmunized pregnancies. These antibodies have been the subject of comparatively little research. This study investigated the incidence and clinical outcome of pregnancies affected by non-D Rh alloimmunization at an Australian tertiary maternity service.

MATERIAL AND METHODS

This was a retrospective study of all pregnancies with non-D Rh antibodies (namely anti-C, -E, -c, -e, -C^w as well as the compound antibodies anti-CD, -cE and -ce) managed at the Royal Women's Hospital, Victoria, Australia, from 2009 to 2013 inclusive. Information collected included maternal demographics, details of the antibodies, course of the pregnancy and neonatal outcomes.

RESULTS

During the study period, 115 non-D Rh alloimmunized pregnancies were identified in 102 mothers. Forty-nine pregnancies reached the critical titer (> 16) from non-D Rh alone and 11 fetuses received intrauterine red blood cell transfusion. Labor was induced or cesarean section performed in 38 cases. Forty-three neonates were admitted to the special care nursery and 59 received phototherapy. Nine received treatment for anemia and 10 neonates received intravenous immunoglobulin.

CONCLUSIONS

Non-D Rh alloimmunization is a relatively uncommon complication of pregnancy, occurring in only .33% of pregnancies in the study period. It can lead to significant fetal/neonatal morbidity (and may lead to mortality). The most severe outcomes (including perinatal deaths) were mostly associated with the compound antibodies anti-CD and anti-cE, or a non-D Rh antibody in conjunction with anti-D.

The Incidence and Effects of Alloimmunization in Pregnancy During the Period 2000 - 2013

INTRODUCTION

The objective of the analysis was to examine the epidemiological aspects of maternal alloimmunization and to determine the most common antibody specificities resulting in hemolytic disease of the newborn (HDN).

MATERIALS AND METHODS

The retrospective epidemiological study encompasses all pregnant women who underwent immunohematological screening and the newborn treated for HDN in the period from 2000 to 2013 in the Herzegovina region.

RESULTS

The indirect Coombs test (ICT) detected antibodies against antigens in 384 (2.4%) pregnant women of the 18 800 who were tested at the Department of Transfusion Medicine. The direct Coombs test (DCT) detected antibodies against antigens in 160 (0.8%) newborn treated for HDN. The results of our 13-year study, in which 60% of the pregnant women had non-RhD antibodies, confirms this finding.

CONCLUSION

However, we have reached the 21st century and the burden of alloimmunisation in pregnancy is still on our backs. The problem of immunization and HDN is still present in our region, which is a neonatal and public health problem.

Alloimmunization due to red cell antibodies in Rhesus positive Omani Pregnant Women: Maternal and Perinatal outcome

OBJECTIVE

This study is aimed to determine the prevalence of alloimmunization due to antibodies to red blood cell (RBC) antigens (other than rhesus [Rh] antigen) and report the maternal, perinatal, and neonatal outcomes.

MATERIALS AND METHODS

A retrospective review of medical records of all patients with minor RBCs antibodies alloimmunization who were followed and delivered at Sultan Qaboos University Hospital, Oman from June 2011 to June 2013. Maternal characteristics, antibody type, antibody titer in addition to perinatal and neonatal outcomes were reviewed.

RESULTS

There were 1160 patients with Rh positive status in the study. The most common ABO blood group was O, followed by A, B, and AB. We found 33 out of 1160 Rh positive women alloimmunized with minor RBCs antibodies that gave a prevalence of minor RBCs alloimmunization of 2.7%. The most frequent antibody was anti-E 38%, followed by anti-c 17% and anti-kell 17%. 6 of these 33 patients were identified to have significant antibody titer, and two cases showed evidence of fetal anemia. Only one case required an intrauterine blood transfusion. The most common neonatal complication was jaundice in 53%, followed by respiratory distress syndrome in 28%. Two cases complicated by neonatal anemia required a postnatal blood transfusion.

CONCLUSION

Alloimmunization with anti-E, anti-c, and anti-kell were the most common antibodies among the study group. Minor RBCs alloimmunization was an important cause of neonatal morbidity.

Hemolytic disease of the fetus and newborn due to multiple maternal antibodies

OBJECTIVE

The objective of the study was to determine whether women with combinations of red blood cell antibodies are more likely to develop significant hemolytic disease of the fetus and newborn than those with single antibodies.

STUDY DESIGN

A retrospective exposure cohort study was conducted of pregnant women with red blood cell antibodies. The development of significant hemolytic disease of the fetus and newborn was then compared between patients with single antibodies and those with multiple antibodies. Data analysis was limited to pregnancies delivering since the year 2000.

RESULTS

Thirteen percent of the patients referred to our program had multiple red blood cell antibodies. Odds of developing significant hemolytic disease of the fetus and newborn for patients with anti-Rh(D) combined with at least 1 additional red blood cell antibody were 3.65 times the odds for women with anti-Rh(D) antibodies in isolation (95% confidence interval, 1.84-7.33). In the setting of multiple antibodies including anti-Rh(D), Rh-positive fetuses/neonates have an increased odds of developing significant hemolytic disease even if the fetus is negative for the other corresponding red blood cell antigen.

CONCLUSION

Women with multiple red blood cell antibodies are more likely to develop significant hemolytic disease of the fetus and newborn than those with a single antibody especially in the presence of anti-(Rh)D. This pathophysiology may suggest a more aggressive immune response in women who develop more than 1 red blood cell antibody.

Haemolytic disease of the fetus and newborn

Haemolytic Disease of the Fetus and Newborn (HDFN) is caused by maternal alloimmunization against red blood cell antigens. In severe cases, HDFN may lead to fetal anaemia with a risk for fetal death and to severe forms of neonatal hyperbilirubinaemia with a risk for kernicterus. Most severe cases are caused by anti-D, despite the introduction of antental and postnatal anti-D immunoglobulin prophylaxis. In general, red blood cell antibody screening programmes are aimed to detect maternal alloimmunization early in pregnancy to facilitate the identification of high-risk cases to timely start antenatal and postnatal treatment. In this review, an overview of the clinical relevance of red cell alloantibodies in relation to occurrence of HDFN and recent views on prevention, screening and treatment options of HDFN are provided.

The Significance of Imunohematology Research in Relation to Menagement of Hemolitical Diseases of the Newborn in Republic of Macedonia

AIM: Prompt discovery of allosensibilisation to RBC’s antigens during pregnancy and successful management of HDFN in Republic of Macedonia, in order to decrease morbidity and mortality of the fetus and the newborn.MATERIALS AND METHODS: The study comprises in total 23,800 patients, 14,858 pregnant women and 8,842 newborn babies.RESULTS: The screening and identification of anti RBC’s antibodies detected in total 216 alloantibodies, out of which 81% (175) had a clinical significance. Out of the above mentioned 164 alloantibodies (65.9%) belong to the Rh system. The most often reason for a severe hemolytic disease is the anti-D antibody. The HDFN symptoms of mild and moderate degree demonstrated 32.5%, and 18.9% had symptoms of severe fetal suffering, and almost half of them (48%) were with or with mild HDFN and had no need of therapy. In 15% it was about alloantibodies of other Rg antigens: anti-C, anti-E and anti-c, at which in most cases there were no signs of HDFN, or it showed weak symptoms (89%), just one case of anti-c ended with intrauterine death.CONCLUSIONS: Anti D antibody represents the most often reason for severe HDFN and displays a need of intrauterine transfusion and exsangvino transfusion. Anti-c is the only antibody that demonstrated the same potential for severe HBN as the anti-D. The most often reason for alloimmunisation of the mother is the lack of RhIG prophylaxis (97.8): postnatal, antenatal and in case of possible sensible conditions during pregnancy. Thus, there is a need and an outmost importance of elaboration and adoption of the National programe for RhIG prophylaxis in Republic of Macedonia.

[Fetomaternal anti-RH3, -4 (anti-E and anti-c) rhesus isoimmunization: a case report]

Hemolytic disease of the newborn caused by maternal isoimmunization has been decreasing over the past 10 years because of prophylactic treatment with anti-RH1 (anti-D) immunoglobulin. Nevertheless, there is an increase in the incidence of both relative and absolute numbers of non-RH1 red-cell maternofetal isoimmunizations, essentially anti-RH4 (anti-c), anti-RH3 (anti-E), and anti-Kell. In 8 to 14% of cases, multispecificity antibodies are present, the most common combination being the association of anti-RH3 and -4. Despite absence of specific prophylactic therapy, anti-RH4 isoimmunization could be as severe as anti-RH1 ; as for anti-RH3, it is usually associated with mild to moderate clinical manifestations. Nevertheless, there are few publications on anti-RH3, -4 maternofetal isoimmunization with a bias toward the most severe cases being reported. We report here a case of nonsevere maternofetal anti-RH3, -4 isoimmunization complicated with severe hyperbilirubinemia and delayed profound anemia. Hyperbilirubinemia was controlled using intensive phototherapy. Although anemia was absent at birth, it appeared progressively with a nadir at 7.8 g/dL at 1-month postnatal age. Blood counts were monitored for 3 months but the patient did not require red blood cell transfusion. This report underlines the need for a prolonged and rigorous pediatric follow-up of children born in the context of maternofetal isoimmunization after the acute neonatal period. Furthermore, it stresses the necessity of DAT testing in all pregnant women, even those who are RH1-positive.

Intravenous Immunoglobulin therapy for anti-E hemolytic disease in the newborn

Anti-E alloimmunisation is a less common cause of haemolytic disease in the newborn (HDN) and is usually associated with mild to moderate clinical manifestations, that are often less severe than anti-D immunisation. Conventional treatments for HDN are phototherapy and exchange transfusion, the latter still representing a high-risk procedure. Currently, intravenous immunoglobulin has been used as alternative treatment for HDN to reduce the need for exchange transfusion, as well as the length of phototherapy and hospitalisation. We report a case of anti-E HDN treated successfully with intravenous immunoglobulin, as adjuvant treatment to phototherapy.

Anti-e alloimmunization: a rare cause of severe fetal hemolytic disease resulting in pregnancy loss

We report a case of severe intrauterine hemolysis caused by sole anti-E alloimmunization. A 36-year-old multipara woman presented with hydrops fetalis at 27 weeks of gestation. She had a history of previous neonatal death. In this pregnancy, she was found to have very high titer of anti-E antibody. Ultrasonography detected marked skin edema, cardiomegaly, hepatosplenomegaly, pleural effusion, ascites, placentomegaly, and polyhydramnios. The Doppler peak systolic velocity in the middle cerebral artery was 0.8 m/s, indicating severe fetal anemia. Multiple intrauterine transfusions for the anemic fetus were administered. However, persistent severe fetal anemia and placentomegaly caused poor neonatal death and mirror syndrome in the mother. Uncommon red blood cell alloimmunization has to be watched for early in any population, especially in a woman with a history of unexplained perinatal loss.

Fetal anemia due to non-Rhesus-D red-cell alloimmunization

Although anti-RhD was once the major etiology of hemolytic disease of the fetus/newborn (HDFN), the widespread adoption of antenatal and postpartum Rhesus immune globulin has resulted in a marked decrease in the prevalence of alloimmunization to the RhD antigen in pregnancy. Maternal alloimmunization to other red cell antigens continues to play a role as the cause of fetal disease since no prophylactic immune globulins are available to prevent the formation of these antibodies. An increasing incidence of the Kell (anti-K1) antibody has been noted in the United States. Guidelines for intervention in cases of irregular red cell antibodies are limited by the bias of anecdotal reports in the literature in favor of severe cases of HFDN. Although most diagnostic protocols used in the management of the RhD-alloimmunized pregnancy can be applied in cases of non-RhD sensitization, Kell (K1 and K2) alloimmunization should be managed more conservatively.

Effect of screening for red cell antibodies, other than anti-D, to detect hemolytic disease of the fetus and newborn: a population study in the Netherlands

BACKGROUND

Hemolytic disease of the fetus and newborn (HDFN) is a severe disease, resulting from maternal red cell (RBC) alloantibodies directed against fetal RBCs. The effect of a first-trimester antibody screening program on the timely detection of HDFN caused by antibodies other than anti-D was evaluated.

STUDY DESIGN AND METHODS

Nationwide, all women (1,002 in 305,000 consecutive pregnancies during 18 months) with alloantibodies other than anti-D, detected by a first-trimester antibody screen, were included in a prospective index-cohort study. In a parallel-coverage validation study, patients with HDFN caused by antibodies other than anti-D, that were missed by the screening program, were retrospectively identified.

RESULTS

The prevalence of positive antibody screens at first-trimester screening was 1,232 in 100,000; the prevalence of alloantibodies other than anti-D was 328 in 100,000, of which 191 of 100,000 implied a risk for occurrence of HDFN because the father carried the antigen. Overall, severe HDFN, requiring intrauterine or postnatal (exchange) transfusions, occurred in 3.7 percent of fetuses at risk: for anti-K in 11.6 percent; anti-c in 8.5 percent; anti-E in 1.1 percent; Rh antibodies other than anti-c, anti-D, or anti-E in 3.8 percent; and for antibodies other than Rh antibodies or anti-K, in none of the fetuses at risk. All affected children, where antibodies were detected, were promptly treated and healthy at the age of 1 year. The coverage validation study showed a sensitivity of the screening program of 75 percent. Five of 8 missed cases were caused by anti-c, with delay-induced permanent damage in at least 1.

CONCLUSION

First-trimester screening enables timely treatment of HDFN caused by antibodies other than anti-D, however, with a sensitivity of only 75 percent. A second screening at Week 30 of c- women will enhance the screening program. Severe HDFN, caused by antibodies other than anti-D, is associated with anti-K, anti-c, and to a lesser extent with other Rh-alloantibodies.

Fetal genotyping for the K (Kell) and Rh C, c, and E blood groups on cell-free fetal DNA in maternal plasma

BACKGROUND

When a pregnant woman has an antibody with the potential to cause hemolytic disease of the fetus and newborn, it is beneficial to determine whether her fetus has the corresponding antigen to assess risk. In many countries this is now done routinely for RhD, by testing cell-free fetal DNA in the maternal plasma. Similar tests for K, C, c, and E are reported.

STUDY DESIGN AND METHODS

Real-time quantitative polymerase chain reaction incorporating an allele-specific primer was developed for detecting the K allele of KEL and the C, c, and E alleles of RHCE. These methods were used to test DNA isolated from plasma of pregnant women with antibodies to K, C, c, or E. Accuracy of the tests was determined by comparing results with serologic tests performed on cord red blood cells (RBCs) after delivery or by molecular genotyping on DNA obtained from fetal cells.

RESULTS

The K test incorporated an allele-specific primer with two locked nucleic acids and a mismatch. In 70 tests, including 27 K+ fetuses, only one false-negative and no false-positive results were obtained. The C, c, and E tests, performed on 13, 44, and 46 samples, respectively, gave rise to no false results.

CONCLUSION

Reliable methods have been developed for predicting fetal K, C, c, and E phenotypes, by testing fetal DNA in the plasma samples of pregnant women whose RBCs lack the corresponding antigens. These methods are now being used routinely in a diagnostic service in the United Kingdom.

Management of pregnancies complicated by anti-Fyaalloimmunization

BACKGROUND

The objective was to evaluate the management and outcome of patients with anti-Fy(a) at the Ohio State University.

STUDY DESIGN AND METHODS

A database search for patients with pregnancies complicated only by anti-Fy(a) from 1959 to 2004. Collected information included maternal testing, fetal therapy, and neonatal outcomes.

RESULTS

The final data set included 18 pregnancies in 15 women where anti-Fy(a) was the only maternal alloantibody present and the fetus was Fy(a) antigen-positive. Maternal antibody titers of at least 32 and optical density at 450 nm values in modified Liley Zone IIB or III identified all fetuses or neonates with significant hemolytic disease (2/18, 11%). No fetuses had hydrops, and there were no deaths attributed to hemolytic disease of the fetus and newborn.

CONCLUSION

Anti-Fy(a) has the potential to lead to significant fetal hemolysis. Management guidelines developed for D sensitization are appropriate for pregnancies complicated by anti-Fy(a) alloimmunization.

High additional maternal red cell alloimmunization after Rhesus- and K-matched intrauterine intravascular transfusions for hemolytic disease of the fetus

OBJECTIVE

Intrauterine transfusion (IUT) is a life-saving therapy for the severely anemic fetus with hemolytic disease. However, maternal additional antibody formation is a complication of the procedure. In this study, we determined antibody formation after introduction of preventive Rh-D, -C, -c, -E, and -e and K matching of IUT donors.

STUDY DESIGN

This was a retrospective follow-up study.

RESULTS

During an 11-year period, 686 Rhesus- and K-matched IUTs were performed in 233 pregnancies and in 95% (652/686) posttransfusion antibody testing was performed after a median interval of 21 days. Twenty-five percent (53/212) of the women formed 64 new antibodies and, compared to our previous study, this incidence was not decreased by the use of Rhesus- and K-matched donors. After delivery, 72% (153/212) of the women had multiple RBC antibodies. Additional antibodies were in 48% (31/64) directed against Rhesus and K antigens, induced by the fetus, or as natural antibodies. In 52% (33/64) the antibodies were directed against non-Rhesus and -K antigens and in 65% (11/17) of eligible cases the IUT donor and not the fetus expressed the corresponding antigen(s).

CONCLUSION

Despite Rhesus- and K-matching, women treated with IUTs still show strikingly broad red cell alloimmunization. More extensive IUT donor red cell matching, including FY, JK, and S antigens, to reduce the formation of new red cell antibodies should be explored.