Effect of Anti-D titers in RhD-negative pregnant women on fetuses and newborns: A retrospective study

BACKGROUND

Transplacental-derived anti-D IgG in RhD-negative pregnant women can trigger an immune response to Rh D-positive red cells in fetuses and newborns. We assessed the effect of anti-D titers in RhD-negative pregnant women on fetuses and newborns.

METHODS

The clinical data of 142 singleton RhD-sensitized pregnancies were retrospectively collected. The pregnant women received routine prenatal care and the newborns had standard care. Based on the tertile categories of the pregnancies, the maximum titers of anti-D IgG in the pregnant women were divided into three groups ranging from low to high as follows: low-titer group (anti-D titer: 1:4-1:128, n = 57); medium-titer group (anti-D titer: 1:256-1:512, n = 50); and high-titer group (anti-D titer: 1:1024-1:4096, n = 35).

RESULTS

The frequencies of major neonatal complications did not significantly differ among the three groups. The high-titer group had the highest frequency of pregnancies requiring intrauterine transfusion (IUT) and number of IUTs among the three groups. The high-titer group had a significantly higher frequency of newborns treated with top-up transfusion, number of top-up transfusions, frequency of newborns treated with exchange transfusion (ET), and number of ETs when compared to the low-titer group.

CONCLUSION

Higher anti-D titers in RhD-negative pregnant women predict more severe fetal and neonatal hemolytic anemia. Increasing maternal anti-D titers results in an increased need for IUTs, and neonatal top-up transfusions and ETs. Methods for reducing titers of anti-D IgG in RhD-sensitized pregnant women warrants further investigation.

Immunohematological testing and transfusion management of the prenatal patient

The primary indication for immunohematological testing in the prenatal patient is to detect and identify maternal red cell antibodies. If there are antibodies that are expected to hemolyze the fetus' red cells, their strength of reactivity must be tested, and the fetus' antigen status determined. After delivery, testing is performed to assess the extent of fetomaternal hemorrhage, as a large hemorrhage may require other therapeutic interventions. Another major role for immunohematological testing is to select blood components appropriately when intrauterine transfusion is required for fetal anemia resulting from maternal alloimmunization or some other cause. Supplementation with molecular methods has transformed the practice of immunohematology, particularly as it applies to typing for the D antigen of the Rh blood group system. Notwithstanding the advances in testing, close coordination and communication between the transfusion service and the obstetrics service are the foundation for ensuring the finest care for prenatal patients, and for new mothers and their infants. This review describes testing and transfusion practices for prenatal patients, using case presentations to highlight the management of selected immunohematological findings. It also includes a discussion of key patient management topics that are currently unresolved.

Immunohaematological conundrums in obstetrics from transfusion services viewpoint in Armed Forces setup

Background

Obstetrics as a speciality has a very long association with the transfusion services and poses its own set of immunohematological (IHL) challenges. A study was carried out to evaluate the spectrum of IHL issues in obstetrics in our setup and to suggest a way forward.

Methods

This study was carried out in a transfusion services setup catering to antenatal care (ANC) clientele in two tertiary-level health care setups. Samples were collected from all ANC patients requiring transfusion and patients reporting for Indirect Coombs Test (ICT). Data included ICT positive cases with implicated alloantibodies, those requiring specialised procedures and the foetal outcome. The results were described using descriptive statistics by frequencies and percentages.

Results

A total of 4683 eligible samples were included in the study, out of 21,893 antenatal patients visiting our setup during study period. One hundred thirty-six ANC patient samples were found to be ICT positive. The most common single alloantibody was anti-D (n = 77, 57.5%). Double antibody positivity was found in 28 patients. Multiple alloantibodies were found in 1 patient. Up to 48% of these allo-anti D cases necessitated specialised procedures.

Conclusion

The IHL issues of obstetrics faced in our setup are no less than that in Indian population. We have much higher frequency of double alloantibody in our ANC population. The authors propose that all multiparous ANC patients, especially with a history of transfusion, irrespective of Rh D status should be screened for irregular alloantibodies to circumvent these issues and the last-minute rush for provision of compatible units.

Anti-RH1 alloimmunization: At what maternal antibody threshold is there a risk of severe fetal anemia?

BACKGROUND

To define a threshold of maternal antibodies at risk of severe fetal anemia in patients followed for anti-RH1 alloimmunization (AI).

STUDY, DESIGN, AND METHODS

We conducted a retrospective study of patients followed for anti-RH1 AI at the Lille University Hospital. The first group, severe anemia, included patients who received one or more in utero transfusions (IUT) or who were induced before 37 weeks of pregnancy for suspected severe fetal anemia. The second group, absence of severe anemia, corresponded to patients without intervention during pregnancy related to AI. Sensitivities, specificities, and positive and negative predictive values for screening for severe fetal anemia were calculated for the antibody thresholds of 3.5 and 5 IU/ml for the quantification.

RESULTS

Between 2000 and 2018, 207 patients were included 135 in the severe anemia group and 72 in the no severe anemia group. No severe anemia was observed for an antibody titer below 16. For an antibody threshold of 3.5 IU/ml, the sensitivity was 98.2%, with 30.2% false positives. All severe anemias were detected in the second trimester; two cases of severe anemia were not detected in the third trimester. For an antibody threshold of 5 IU/ml, the sensitivity was lower at 95.6%, with five cases of severe anemia not detected.

CONCLUSION

The antibody threshold of 3.5 IU/ml for the quantification and 16 for the titration allow targeting patients requiring close monitoring by an experienced team in case of anti-RH1 AI.

Population-based incidence and risk factors for cholestasis in hemolytic disease of the fetus and newborn

OBJECTIVE

To estimate the incidence of cholestasis in neonates with hemolytic disease of the fetus and newborn (HDFN) and investigate risk factors and long-term liver disease.

STUDY DESIGN

A population-based cohort study of all infants born with HDFN within the Stockholm region between 2006 and 2015. The study period was the first 90 days of life, and presence of any chronic liver disease was evaluated at two years of age.

RESULTS

Cholestasis occurred in 7% (11/149). Median age at detection was 1.1 days. Intrauterine blood transfusions and maternal alloimmunization with multiple red blood cell antibodies including D-, c- or K-antibodies were independent risk factors for cholestasis. No infant had chronic liver disease at two years of age.

CONCLUSIONS

Infants with severe HDFN have increased risk for cholestasis, particularly those requiring multiple intrauterine transfusions. Early and repeated screening for conjugated hyperbilirubinemia in the first week of life is needed to ensure adequate management.

The combined effect of anti-D and non-D Rh antibodies in maternal alloimmunization

Objective

This study aims to investigate the distribution of antibodies that cause hemolytic disease of the fetus and newborn (HDFN) and compare the clinical outcomes of pregnancies affected by anti-D and anti-D combined with non-D Rh alloimmunization.

Materials and Methods

We retrospectively searched and obtained the perinatal and neonatal data of patients with anti-D antibodies and anti-D combined with non-D Rh antibodies (anti-c, -C, -e, -E, and -Kell) from October 2015 to December 2018 at the University of Health Sciences Turkey, Kanuni Sultan Süleyman Training and Research Hospital. Univariate and multiple logistic regression analyses and adjusted odds ratios with their confidence intervals were used to define independent risk factors for non-D antibody positive.

Results

The severe fetal hydrops rate was significantly higher in the anti-D combined non-D group (3/25, 12%) than in the anti-D group (1/128, 0.08%, p<0.001). The intrauterine transfusion (IUT) requirement in the anti-D combined non-D group (16/25, 64%) tended to be significantly higher than that in the anti-D group (5/128, 7.46%, p<0.001). The incidence of neonatal exchange transfusion, top-up transfusion, and postnatal phototherapy frequency in the anti-D combined non-D group was significantly higher than in the anti-D group.

Conclusion

Anti-D combined with another non-D Rh alloantibody resulted in significantly higher HDFN rates than the anti-D alloimmunized pregnancies. Also, anti-D in association with non-D Rh antibodies resulted in more severe HDFN requiring more invasive treatment procedures, including IUT, neonatal exchange transfusion, or top-up transfusion.

Management and clinical consequences of red blood cell antibodies in pregnancy: A population-based cohort study

INTRODUCTION

Anti-D alloimmunization is the most common cause of severe hemolytic disease of the fetus and newborn (HDFN). The management of pregnancies affected by less frequent red blood cell (RBC) antibodies poses a challenge to clinicians, and perinatal outcomes are less well described. This study aimed to describe the frequency of clinically significant RBC antibodies in our pregnant population and analyze the risk of prenatal and postnatal treatment for HDFN in relation to our national risk classification system and management guidelines.

MATERIAL AND METHODS

A retrospective cohort study in the population of all alloimmunized singleton pregnancies in the Stockholm region 1990-2016. Descriptive summaries of different RBC antibodies and pregnancy outcomes were presented, the risks of intrauterine blood transfusion (IUT) and neonatal treatment for HDFN were estimated by type of antibodies.

RESULTS

Of the 1724 alloimmunized pregnancies, 1079 (63%) were at risk of HDFN and constituted our study cohort. Anti-D was detected in 492 (46%) pregnancies, followed by anti-E in 161 (15%), and anti-c in 128 (12%). Eighty-seven (8%) pregnancies had IUT, with the highest risk in pregnancies affected by anti-D combined with other antibodies. The maximum titer recorded before IUT was 64 or above, except for two pregnancies affected by anti-c, for which the maximum titers were 8 and 16. For the 942 (95%) live-born neonates from 992 alloimmunized pregnancies without IUT, the median gestational age at birth was 38⁺⁵  weeks compared with 35⁺⁵  weeks for those who had IUT. Neonatal treatment was most common in the anti-D alone and anti-D combined groups, with 136 (57%) and 21 (44%), respectively, treated with phototherapy and 35 (15%) and 9 (20%) receiving exchange transfusions, respectively. For pregnancies complicated by moderate- and low-risk antibodies, phototherapy was less frequent (32 [36%] and 21 [19%]) and exchange transfusion was rare (5 [6%] and 3 [3%]).

CONCLUSIONS

Anti-D, especially in combination with other antibodies, presents the highest risk of severe HDFN. The classification of less frequent and less well-known RBC antibodies into risk groups can help clinicians in assessing the risk of HDFN and counseling alloimmunized pregnant women regarding the risk of prenatal and postnatal treatments.

Prediction of ABO hemolytic disease of the newborn using pre- and perinatal quantification of maternal anti-A/anti-B IgG titer

BACKGROUND

Hemolysis in fetus/newborns is often caused by maternal antibodies. There are currently no established screening procedures for maternal ABO antibodies harmful to fetus/newborn. We investigated the clinical significance, and predictive value of maternal anti-A/B titer for hyperbilirubinemia in ABO-incompatible newborns.

METHODS

We conducted a case-control study of blood group O mothers and their ABO-compatible (O) vs. -incompatible (A/B) newborns receiving phototherapy, and of ABO-incompatible newborns receiving phototherapy vs. no phototherapy. Newborn data and treatment modalities were recorded, and total serum bilirubin and hemoglobin were measured. Maternal anti-A/B immunoglobulin-γ (IgG) titers were measured prenatally and perinatally, and negative and positive predictive values (NPV, PPV) were calculated to assess the risk of developing hyperbilirubinemia requiring phototherapy.

RESULTS

We found a significantly higher maternal IgG antibody titer in the case group (p < 0.001). Maternal anti-A/B titers at first trimester had modest predictive values: NPV = 0.82 and PPV = 0.65 for neonatal hyperbilirubinemia; titers at birth improved the predictive values: NPV = 0.93 and PPV = 0.73. Newborn hemoglobin was significantly lower in incompatibles compared to compatibles (p = 0.034). Furthermore, increased anti-A/B IgG production during pregnancy was associated with hyperbilirubinemia and hemolysis in incompatible newborns.

CONCLUSIONS

There was a significant association between maternal anti-A/B IgG titer and hyperbilirubinemia requiring treatment.

IMPACT

Maternal anti-A/B IgG titer in the first trimester and at birth is predictive of hemolytic disease of the ABO-incompatible newborn. Increased IgG anti-A/B production throughout pregnancy in mothers to ABO-incompatible newborns developing hyperbilirubinemia contrasts a constant or reduced production in mothers to newborns not developing hyperbilirubinemia. Screening tools available in most immunohematology laboratories can identify clinically important IgG anti-A/B. Use of maternal samples taken at birth yielded NPV = 0.93 and PPV = 0.73.

A comparative study on perinatal outcomes of red blood cell-alloimmunized pregnancies with anti-RhD in combination and anti-RhD alone in China

BACKGROUND AND OBJECTIVES

The advent of intrauterine transfusion (IUT) has improved the survival of severe foetal anaemia. The aim of this study was to compare the perinatal outcomes of red blood cell (RBC)-alloimmunized pregnancies with anti-RhD in combination and anti-RhD alone in China.

MATERIALS AND METHODS

A retrospective study was conducted involving RBC-alloimmunized pregnancies with anti-RhD in combination and anti-RhD alone admitted to The First Affiliated Hospital, Sun Yat-sen University, between January 2007 and December 2019. Obstetric data and neonatal outcomes were compared.

RESULTS

A total of 165 alloimmunized pregnancies were identified, with 32 pregnancies in the anti-RhD-in-combination group (25 pregnancies with anti-RhD + anti-RhC and 7 pregnancies with anti-RhD + anti-RhE) and 133 pregnancies in the anti-RhD-alone group. The anti-RhD-in-combination group had significantly higher frequency of IUTs than the anti-RhD-alone group (59.4% [19/32] vs. 30.1% [40/133]; p < 0.01). The postnatal frequency of top-up transfusions was significantly higher in the anti-RhD in combination group than the anti-RhD-alone group (90.6% [29/32] vs. 70.7% [94/133]; p = 0.02). There was no significant difference in the frequency of exchange transfusions (ETs) between the two groups (15.6% [5/32] vs. 17.3% [23/133]; p = 0.82).

CONCLUSIONS

Compared to alloimmunized pregnancies with anti-RhD alone, pregnancies with anti-RhD in combination with anti-RhC or anti-RhE have an increased requirement for antenatal IUTs and postnatal top-up transfusions but do not have an increased need for ETs.

Prenatal prediction of fetal Rh C, c and E status by amplification of maternal cfDNA and deep sequencing

BACKGROUND

The Rh blood group system has considerable clinical importance. The C, c, and E antigens are targets of alloantibodies. Anti-C, anti-c or anti-E alloreactive antibodies produced in pregnant women can cause anemia of a fetus carrying the corresponding antigens.

AIMS

Based on NGS technology, we have developed a noninvasive diagnostic assay to predict the fetal blood group of C, c or E antigens by sequencing cell-free DNA (cfDNA) during pregnancy.

MATERIALS AND METHODS

The SNVs underlying either the C, c or E antigens were PCR amplified and sequenced using NGS on a MiSeq instrument. The DNA sequences encoding the C, c or E antigen were counted, as were the number of total sequences. Based on the percentage of fetally derived target SNVs inherited from the father, the fetal blood group could be predicted.

RESULTS

The results of 55 consecutive RHCE prenatal analyses with postnatal serological blood group determination of 30 newborns showed no discordant results. A threshold discerning positive from negative samples was set at 0.05% specific reads.

DISCUSSION

Noninvasive, prenatal prediction of fetal blood groups by sequencing cfDNA for the detection of low-level RHCE*C, RHCE*c and RHCE*E sequences was established as an accurate and robust assay applicable for use in clinical settings.

Frequency and clinical significance of red cell antibodies in pregnancy - A prospective study from India

Background

For appropriate management of hemolytic disease of the fetus and newborn (HDFN), it is important to detect irregular red cell antibody in the antenatal period. Though it is a simple one-step method, it is not part of routine antenatal screening in many developing countries. To reiterate the importance of antenatal antibody screening, we have assessed the frequency and clinical significance of irregular red cell antibodies in our patient population.

Materials and Methods

A prospective study was carried out from October 2013 to May 2015 at a tertiary care center from south India. All antenatal samples received by the laboratory for red cell antibody screening were screened using a commercial three-cell screening panel. Antibody identification along with further Immunohematological techniques as required were performed for cases with positive screening results. Neonates of the alloimmunized cases were followed up to determine the clinical significance of the antibody.

Results

A total of 2336 antenatal mothers were screened for red cell antibodies. The overall rate of alloimmunization in the study group was 2.27%. Alloimmunization rate among RhD-negative pregnancies was 6.9%. Other than anti-D (49%), we identified anti-D + anti-C (5%), anti-G (5%), anti-c (5%), anti-E (2%), anti-e (2%), anti-H (Bombay phenotype) (7%), anti-M (2%), anti-Lea (2%), anti-Leb (12%), and autoantibodies (9%) in the maternal serum. Anti-D, anti-D + anti-C, anti-G, anti-c, and anti-H were found to be clinically significant in this study.

Conclusion

This study showed that 1 in 125 RhD-positive pregnancies can develop red cell alloantibodies. Hence, implementing routine antenatal antibody screening irrespective of RhD status is essential.

Hemolytic disease and reticulocytopenia of the newborn attributable to maternal immunoglobulin G anti-M reacting optimally at cold temperatures

BACKGROUND

Hemolytic disease of the fetus and newborn (HDFN) attributable to anti-M is rare, although case reports implicate anti-M in varying severities of HDFN, including fetal hydrops and intrauterine death.

CASE DESCRIPTION

We describe the case of a newborn with HDFN associated with an atypical immunoglobulin (Ig) G anti-M that reacted best at cold temperatures. The maternal antibody detected in pregnancy was not reactive at 37°C, and a direct antiglobulin test (DAT) on red blood cells (RBCs) from the newborn was negative, suggesting an anti-M that should not have been clinically relevant. However, the infant developed hyperbilirubinemia (bilirubin level, 17.6 mg/dL), hemolytic anemia (hemoglobin nadir, 5.5 g/dL), and reticulocytopenia. Laboratory testing demonstrated the presence of an IgG anti-M in maternal and neonatal samples reacting best at 4°C. This passively acquired IgG anti-M provoked hemolytic anemia in the infant and likely suppressed erythropoiesis, resulting in reticulocytopenia with prolonged anemia. He was treated for IgG anti-M HDFN with 10 intravenous Ig infusions and 10 days of oral prednisone followed by a taper. He required seven transfusions with M- RBCs. His hemoglobin level normalized at 3 months of age. Follow-up at 2 years revealed no hematologic or neuro-developmental concerns.

CONCLUSION

To our knowledge, this is the second report of HDFN attributable to an IgG anti-M reacting preferentially at cold temperature with no 37°C reactivity. Clinically relevant IgG anti-M may elude standard testing. Early recognition and testing for cold-reacting IgG anti-M should be considered for newborns with hemolysis, a negative DAT, and prolonged anemia.

Implementation of a Standardized Prenatal Testing Protocol in an Integrated, Multihospital Health System

OBJECTIVES

When our institution grew into an integrated multihospital health system, we were faced with the need to standardize laboratory processes, including blood bank processes, across all locations. The purpose of this article is to describe our experience of standardizing the protocols for prenatal testing.

METHODS

For each hospital in the system, we established service tiers to define tests offered on site or referred to another location. For each prenatal test, we examined the related processes for ways to improve uniformity, efficiency, and reliability. Throughout this process of standardization, we collaborated with the clinical services to gain concurrence on the interpretation and reporting of results.

RESULTS

We created and implemented a uniform protocol for testing prenatal patients. The protocol standardized the definition of critical titer, instituted criteria to identify passively acquired anti-D, and established a process for the follow-up of women with inconsistent serologic results on Rh(D) typing.

CONCLUSIONS

Close collaboration with the clinical services ensured that our testing protocol is aligned with the needs of the integrated obstetrics service in the health system. The approach described in this article may provide a plan outline for pathologists facing similar challenges at other integrated health systems.

Title: Effect of multiple maternal red cell alloantibodies on the occurrence and severity of Hemolytic Disease of the Fetus and Newborn

INTRODUCTION

Antenatal antibody screening in India is focused on the detection of anti-D in RhD-negative mothers. HDFN outcome can also be affected by the presence of antibodies other than anti-D. We planned this study to find the impact of 'anti-D in combination with additional antibodies' on the development and severity of HDFN compared with 'anti-D alone'.

METHODS

This is a retrospective study performed at a referral center in northern India from October 2015 to March 2018. Antibody screening was performed on women with complicated obstetric history. Women with anti-D antibody were included in the study and categorized on the basis of presence of additional antibody (anti-D alone or in combination with other antibody). Various clinical, laboratory & interventional parameters were used to define HDFN and severe HDFN. Perinatal outcome was then compared between the two groups.

RESULTS

A total of 176 women with anti-D antibody were included in the study. Of these, 136 cases (77.3%) had anti-D alone while at least one additional antibody was present in 40 (22.7 %) cases. Most common additional antibodies were anti-C, anti-E and anti-c. After excluding 46 women for various reasons, 130 women were left for final analysis. Approximately 57% and 78% of cases were affected by severe HDFN amongst women with anti-D alone and in combination, respectively. Relative risk of developing severe HDFN was 1.7 times higher in women with additional antibody.

CONCLUSIONS

Patients with combination antibodies were found to have more severe HDFN compared to the ones with anti-D alone.

The rhesus incompatible pregnancy and its consequences for affected fetuses and neonates

Rhesus incompatibility in pregnancy may result in haemolytic disease of the fetus and newborn (HDFN). This review discusses the fetal, neonatal and long-term consequences of HDFN and its management. Untreated, the fetal and neonatal prognosis of HDFN is poor. Provision of intravascular intrauterine transfusion (IUT) in a dedicated referral centre significantly reduces perinatal loss. Early-onset, severe fetal anaemia carries a greater risk of adverse fetal and neonatal outcomes and is less amenable to treatment with IUT. Interventions to prevent and treat severe, early onset disease have been investigated, however evidence from randomised controlled trials is required. Neonatal consequences of Rhesus haemolytic disease include early and late postnatal anaemia, and hyperbilirubinaemia leading to bilirubin-induced neurological dysfunction. Neurodevelopmental impairment and adult cardiovascular disease are long-term complications that have been reported in association with severe fetal anaemia. Strategies to prevent fetal hydrops, and further research into the long-term impacts of fetal anaemia may improve health outcomes for adult survivors of HDFN.

Distribution of maternal red cell antibodies and the risk of severe alloimmune haemolytic disease of the foetus in a Chinese population: a cohort study on prenatal management

BACKGROUND

Haemolytic disease of the foetus and newborn (HDFN) is the most common aetiology of haemolytic anaemia and hyperbilirubinaemia in foetuses and neonates. Studies on the distribution of antibodies that cause haemolytic disease of the foetus (HDF) in China are limited, and the effects of multiple antibodies on the severity of HDF need further evaluation.

METHODS

An observational cohort study from January 2005 to December 2019 was conducted in two hospitals affiliated with Sun Yat-sen University. Maternal red cell alloimmunization was identified by the Guangzhou Blood Centre. In total, 268 pregnant woman-foetus pairs were divided into four groups according to the type of maternal alloantibodies: anti-D, anti-D combined with other antibodies, other single-antibody and other multiple antibodies. The obstetric history, antibody characteristics, incidence of severe HDF and foetal outcomes were collected and compared. Logistic regression analysis of the risk factors for HDF and survival analysis of the severe HDF-free interval were conducted.

RESULTS

Anti-D was the most common cause of HDF, followed by anti-M. No anti-K- or isolated anti-c-associated HDF was found. The incidence of severe HDF was higher in the group with anti-D combined with other antibodies than in the group with anti-D alone (P = 0.025), but no significant difference was found in haemoglobin level and reticulocyte count in the anaemic foetuses between these two groups. Foetuses in the other single-antibody group had a lower reticulocyte count (P = 0.007), more IUTs (P = 0.007) and an earlier onset of severe HDF (P = 0.012). The maximum antibody titre was significantly lower in the other single-antibody group than in the anti-D group (P < 0.001). A high maternal antibody titre (P < 0.001), multiple affected pregnancies (P < 0.001) and other single-antibody (P = 0.042) were independent risk factors for HDF. A higher reticulocyte count (P = 0.041) was an independent risk factor for severe HDF in anaemia foetuses affected by Rh(D) alloimmunization.

CONCLUSIONS

The distribution of HDF-associated antibodies in China is different from that in Western countries. Other single non-Rh(D) antibodies could increase the risk of HDF, and anti-D combined with other antibodies would not influence the severity of foetal anaemia compared with anti-D alone.

Monitoring of prenatal patients using a combined antibody titre for Rh and non-Rh antibodies

OBJECTIVES

This was a laboratory exercise designed to determine whether combined antibody titrations in the presence of multiple antibodies achieve a critical level earlier or at the same time as antibodies having individual antibody titrations.

BACKGROUND

Management of haemolytic disease of the fetus and newborn involves monitoring maternal antibody concentration by antibody titration. Separate titrations are generally performed for each antibody.

METHOD

Thirty-one samples containing combinations of two different Rh and/or non-Rh antibodies were examined with separate titres for each antibody and one single combined titration.

RESULTS

Of 31 samples, 19 (61.3%) showed an increased combined titre. Of 12 samples that showed no increase, 10 contained a separate titre of <1 for either one or both antibodies. Where both antibodies had a separate titre of ≥1, 15 of 17 (88.2%) showed an increased combined titre. In contrast to the separate titration method, no decrease in titre level was observed using the combined method.

CONCLUSION

Where two antibodies are present, titrations performed by a combined method will produce titre levels equal to or higher than antibodies titred individually. Therefore, a combined titration can be expected to reach a critical titre level as early as, or earlier in gestation than, antibodies monitored by a single titration method. Further studies relating fetal outcomes to titration methodology would be valuable in determining the validity of this approach for prenatal management. Cost-effectiveness of this approach to prenatal screening should also be assessed.

Rhesus D alloimmunization in pregnancy from 1996 to 2015 in Iceland: a nation-wide population study prior to routine antenatal anti-D prophylaxis

BACKGROUND

Rhesus D (RhD) incompatibility is still the most important cause of hemolytic disease of the fetus and newborn (HDFN) worldwide. The aim of this study was to investigate the incidence, causes, and consequences of anti-D alloimmunizations in pregnancy in Iceland, prior to implementation of targeted routine antenatal anti-D prophylaxis (RAADP) in 2018.

STUDY DESIGN AND METHODS

This was a nation-wide cohort study of 130 pregnancies affected by RhD alloimmunization in Iceland in the period from 1996 through 2015. Data were collected from transfusion medicine databases, medical records, and the Icelandic Medical Birth Register.

RESULTS

Of 130 RhD alloimmunizations, 80 cases (61.5%) represented new RhD immunization in the current pregnancy. Sensitization was discovered in the third trimester in 41 (51.3%) and occurred in the first pregnancy in 14 cases (17.5%). The most likely causative immunization event was the index pregnancy for 45 (56.25%), a previous pregnancy/birth for 26 (32.5%), abortion for 3 (3.75%), and unknown for 6 women (7.5%). Higher anti-D titers were associated with shorter gestational length, cesarean sections, positive direct antiglobulin test (DAT), and severe HDFN. Intrauterine transfusion (IUT) was performed in five pregnancies (3.8%), and 35 of 132 (26.5%) live-born neonates received treatment for HDFN; 32 received phototherapy (24.2%), 13 exchange transfusion (9.8%), and seven simple blood transfusion (5.3%).

CONCLUSION

In about half of cases, RhD alloimmunization was caused by the index pregnancy and discovered in the third trimester. Thus, the newly implemented RAADP protocol should be effective in reducing the incidence of RhD immunization in Iceland in the future.

Prevalence and obstetric outcome of women with red cell antibodies in pregnancy at the Leeds Teaching Hospitals NHS Trust, West Yorkshire, England

OBJECTIVE

The prevalence of red cell antibodies in pregnancy varies with ethnicity and geographical location, while the obstetric outcome depends on the available standard of care. Despite being the tertiary fetal medicine centre in West Yorkshire, the prevalence of red cell antibodies, and the outcome of pregnancies associated with these antibodies at the Leeds University Teaching Hospitals Trust remains unreported. This article aims to provide this information for the purpose of patient education and counselling.

STUDY DESIGN

The data of pregnant women with red cell antibodies between January 2011 and December 2016 was obtained from the Trust's database and reconciled with the Fetal Medicine Unit records using Viewpoint©. Fetal anaemia requiring in utero transfusion (IUT) was defined as a Middle Cerebral Artery Peak Systolic Velocities ≥ 1.5multiple of the median expected for gestational age. The mean gestational age at delivery, and perinatal outcomes of the pregnancies were recorded.

RESULT

Overall, 398 of the 96, 692 pregnant women that were screened had red cell antibodies, giving a prevalence of 1: 242 pregnancies. The Anti- E and Anti-M antibodies were the most common (114 women; 28.6%, and 112 women; 28.1% respectively), but did not cause fetal anaemia in isolation, while anti-D alloimmunization was the predominant indication for in-utero transfusion (IUT). Anti-DE and anti-Kell antibodies had the highest mean number of transfusions per pregnancy. The mean gestational age at delivery was 34 ± 2weeks. Post-transfusion fetal demise was recorded in two hydropic fetuses, both at a gestational age of 25 weeks; giving a transfusion-related mortality rate of 2.5%.

CONCLUSION

The prevalence of red cell antibodies at West Yorkshire is lower compared with reports from other Caucasian populations.Nevertheless, these antibodies are important causes of iatrogenic preterm delivery and fetal morbidity. The prognosis is however good with prompt diagnosis and management.

RBC alloantibody prevalence and specificity in a Western Norwegian tertiary hospital

BACKGROUND AND OBJECTIVE

Although several studies focus on red blood cell (RBC) alloantibody distribution in selected patient populations, few address the specificity and frequency in all relevant groups. This study reports alloantibody frequency, distribution and the relationship to age and gender in blood donors, pregnant women and potential recipients of blood products.

METHODS

This historical cohort study included 55 462 consecutive antibody screening tests from a tertiary Western Norwegian Hospital. Descriptive statistics were performed, and the results were compared with the literature.

RESULTS

The detection and immunisation frequency for the whole cohort were 0·39 and 0·51%, respectively, whereas the RBC alloantibody prevalence was 0·73%. The most frequent RBC alloantibodies were anti-E (20·1%), anti-M (18·7%), anti-K (9·8%), anti-D (8·9%) and anti-Fy(a) (7·0%). In pregnant women, the most frequent RBC alloantibodies were anti-M, anti-D and anti-Le(a) (20·8, 18·9 and 18·9%, respectively), whereas there was no anti-K detected. Anti-E and anti-M were the dominating RBC alloantibodies in the pre-transfusion testing of in-hospital patients (24·1 and 17·1%, respectively). Eighteen (9·2%) persons in the total cohort had two RBC alloantibodies, six persons had three alloantibodies, and two persons had four alloantibodies. Rh and K typing to prevent future immunisations was only performed in 21·0% of the individuals who presented with a new alloantibody; despite that, 50·5% of the detected alloantibodies had such specificities.

CONCLUSIONS

The immunisation frequency and the level of anti-K are low compared to national and international studies. Rh and K phenotype-matched blood transfusions might be a feasible future strategy to further decrease RBC alloantibodies.

Approach to a Pregnant Woman with Anti D + Anti C Reactivity Pattern: A Diagnostic Conundrum

The Rhesus G antigen is present on all RBCs that are C+ and also on most D+ RBCs. Due to this co-distribution of G with either C or D antigen, it mimics a reactivity pattern of anti C + anti D on Indirect Antiglobulin Test (IAT), though the role of Anti G in causing Hemolytic Disease of Newborn (HDN) is controversial. The differentiation of anti D, anti C, and anti G is essential particularly in pregnant females. We hereby report a rare case of anti G with anti D and anti C in a pregnant woman with emphasis on approach to identify anti D+C+G and its implications.

Association of HLA-DRB1 and HLA-DQB1 with red-blood-cell alloimmunization in the Czech population

BACKGROUND AND OBJECTIVES

Alloimmune antibodies against red-blood-cell (RBC) antigens induced in susceptible individuals (responders) by transfusion, pregnancy or transplantation may have serious clinical consequences. The aim of this study was to investigate association of alloimmunization against selected RBC antigens with HLA-Class II.

MATERIALS AND METHODS

A total of 230 responders (106 monoresponders and 124 multiresponders) were enrolled into the study. HLA-DRB1 and HLA-DQB1 variants were determined by PCR-SSO and their frequencies compared between the patients (patient subgroups) and 375 ethnically and regionally matched controls.

RESULTS

Development of multiple RBC antibodies was associated with HLA-DRB1*15 and HLA-DQB1*06 allelic groups in the patients, with the relationship being particularly apparent in those with anti-C+D antibodies. Furthermore, DRB1*13 and DQB1*06 were more frequent in multiresponders with anti-E+c antibodies and DRB1*03 and DQB1*02 in those with anti-E+Cw.

CONCLUSION

For the first time, we confirmed the association of HLA-DRB1*15 with RBC antibody multiresponder status and found HLA-Class II associations for three frequent RBC antibody combinations. Our data support the concept that HLA restriction plays an important role in the response to RBC alloantigens.

What is it really? Anti-G or Anti-D plus Anti-C: Clinical Significance in Antenatal Mothers

G antigen of Rh blood group system is present either along with D and/or C positive red cells. Hence, [serologically anti-G presents with the similar picture as that of multiple antibodies (anti-D + anti-C). Differentiating them is important as anti-D + anti-C causes severe hemolytic disease of the fetus and newborn than anti-G. In pregnancies with anti-G alone, alloimmunization due to D antigen could be prevented by prophylactic administration of RhIg. Differentiating between anti-D + C from anti-G in alloimmunized pregnant mothers becomes essential. Sera from antenatal mothers, whose antibody identification by 11-cell panel gave a pattern for anti-D and anti-C were selected. Extended phenotyping for Rh system was performed for these antenatal cases. Differential adsorption and elution testing using R₂R₂ cells initially and r'r cells subsequently were performed to distinguish anit-G from anti-D + anti-C. Antibody titers of these antibodies were determined and their clinical outcome in the newborn was followed. A pattern suggestive of anti D and anti C on antibody identification were observed in six antenatal cases. On further workup 50 % of them confirmed to have anti G. Antibody titers of anti-G and anti-C were lower than that of Anti-D. All newborns were sensitized in vivo and the antibody specificity in them were confirmed with elution studies. The mothers who had only anti-G were subsequently administered with an appropriate dose of RhIg.Differential adsorption and elution studies help in identifying anti-G and distinguishing it from anti-D plus anti-C, thus helping in better patient management.

Red cell alloimmunization in RhD positive pregnant women and neonatal outcome

The frequency of red blood cell (RBC) alloimmunization in RhD positive pregnant women is not known in our population. We planned to determine its frequency and correlation with neonatal outcome. We included 1000 RhD positive pregnant women: 500 had 'normal pregnancy' (Group I) and another 500 had 'high risk pregnancy' (Group II). ABO and extended Rh phenotyping were done by tube technique, antibody screening and identification by gel technique. For alloimmunized women, the paternal and neonatal ABO and extended Rh typing were done. Neonatal direct antiglobulin test (DAT) was also done and their clinical outcome observed. The frequency of RBC alloimmunization was 0.7% (7/1000) and all these women were from group II (p = 0.015). The alloantibodies were anti-E (85.7%), anti-c (71.4%), anti-Cw (14.3%) and anti-S (14.3%). Also, 6 women had history of transfusion (p < 0.01). Of the 7 neonates born to alloimmunized mothers, 4 (57.14%) had a positive DAT. The mean duration of phototherapy was higher in the DAT positive neonates (p < 0.01) and 2 (50%) required exchange transfusion. Thus, the frequency of alloimmunization was 0.7% in RhD positive pregnant women. High risk pregnancies and antenatal patients having a history of blood transfusion should be considered for regular antibody screening.

Next-Generation Sequencing for Antenatal Prediction of KEL1 Blood Group Status

The KEL1 antigen can give rise to immunization of KEL2 mothers. Maternal antibodies can be transferred to the fetus and destroy fetal red blood cells and their stem cell precursors and give rise to serious fetal disease. It is important to be able to predict the fetal KEL status in order to intervene in those pregnancies where the fetus is at risk, and to ascertain when the fetus is not at risk. Technically it can be demanding to predict KEL1 status from a maternal blood sample. The KEL1 allele is based on a single SNP present in about 1-10 % of cell-free maternal DNA after gestation week 10. Here we describe our protocol for antenatal prediction of fetal KEL1 status by NGS analysis of maternal DNA on a MiSeq instrument.

Noninvasive Antenatal Determination of Fetal Blood Group Using Next-Generation Sequencing

Hemolytic disease of the fetus and newborn (HDFN) is a condition characterized by a decreased lifespan of fetal red blood cells caused by maternally produced allospecific antibodies transferred to the fetus during pregnancy. The antibodies bind to the corresponding blood group antigens on fetal red blood cells and induce hemolysis. Cell-free DNA derived from the conceptus circulates in maternal blood. Using next-generation sequencing (NGS), it can be determined if this cell-free fetal DNA encodes the corresponding blood group antigen that is the target of the maternal allospecific antibodies. This determination carries no risk to the fetus. It is important to determine if the fetus is at risk of hemolysis to enable timely intervention. Many tests for blood groups are based solely on the presence or absence of a single nucleotide polymorphism (SNP). Antenatal determination of fetal blood group by NGS analysis holds advantages over polymerase chain reaction (PCR) determination based on allele specific amplification.

One size will never fit all: the future of research in pediatric transfusion medicine

There is concern at the National Heart, Lung, and Blood Institute (NHLBI) and among transfusion medicine specialists regarding the small number of investigators and studies in the field of pediatric transfusion medicine (PTM). Accordingly, the objective of this article is to provide a snapshot of the clinical and translational PTM research considered to be of high priority by pediatricians, neonatologists, and transfusion medicine specialists. Included is a targeted review of three research areas of importance: (i) transfusion strategies, (ii) short- and long-term clinical consequences, and (iii) transfusion-transmitted infectious diseases. The recommendations by PTM and transfusion medicine specialists represent opportunities and innovative strategies to execute translational research, observational studies, and clinical trials of high relevance to PTM. With the explosion of new biomedical knowledge and increasingly sophisticated methodologies over the past decade, this is an exciting time to consider transfusion medicine as a paradigm for addressing questions related to fields such as cell biology, immunology, neurodevelopment, outcomes research, and many others. Increased awareness of PTM as an important, fertile field and the promotion of accompanying opportunities will help establish PTM as a viable career option and advance basic and clinical investigation to improve the health and wellbeing of children.

Responder individuality in red blood cell alloimmunization

Many different factors influence the propensity of transfusion recipients and pregnant women to form red blood cell alloantibodies (RBCA). RBCA may cause hemolytic transfusion reactions, hemolytic disease of the fetus and newborn and may be a complication in transplantation medicine. Antigenic differences between responder and foreign erythrocytes may lead to such an immune answer, in part with suspected specific HLA class II associations. Biochemical and conformational characteristics of red blood cell (RBC) antigens, their dose (number of transfusions and pregnancies, absolute number of antigens per RBC) and the mode of exposure impact on RBCA rates. In addition, individual circumstances determine the risk to form RBCA. Responder individuality in terms of age, sex, severity of underlying disease, disease- or therapy-induced immunosuppression and inflammation are discussed with respect to influencing RBC alloimmunization. For particular high-risk patients, extended phenotype matching of transfusion and recipient efficiently decreases RBCA induction and associated clinical risks.

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.

Integration of noninvasive prenatal prediction of fetal blood group into clinical prenatal care

Incompatibility of red blood cell blood group antigens between a pregnant woman and her fetus can cause maternal immunization and, consequently, hemolytic disease of the fetus and newborn. Noninvasive prenatal testing of cell-free fetal DNA can be used to assess the risk of hemolytic disease of the fetus and newborn to fetuses of immunized women. Prediction of the fetal RhD type has been very successful and is now integrated into clinical practice to assist in the management of the pregnancies of RhD immunized women. In addition, noninvasive prediction of the fetal RhD type can be applied to guide targeted prenatal prophylaxis, thus avoiding unnecessary exposure to anti-D in pregnant women. The analytical aspect of noninvasive fetal RHD typing is very robust and accurate, and its routine utilization has demonstrated high sensitivities for fetal RHD detection. A high compliance with administering anti-D is essential for obtaining a clinical effect. Noninvasive fetal typing of RHC/c, RHE/e, and KEL may become more widely used in the future.

Hemolytic disease of the fetus and newborn with late-onset anemia due to anti-M: a case report and review of the Japanese literature

Hemolytic disease of the fetus and newborn (HDFN) attributed to M/N-incompatibility varies from asymptomatic to lethally hydropic. Case reports are rare, and the clinical significance of anti-M is not completely understood. A challenging case of HDFN due to anti-M prompted an investigation of the Japanese literature, in order to characterize the clinical spectrum of M/N-incompatibility pregnancies in Japan and report results to English-language readers. Japanese reports of HDFN attributed to M/N incompatibility were compiled. Abstracted data include maternal antibody titers at delivery, fetal direct antiglobulin test, hemoglobin, total bilirubin, reticulocyte count at birth, and therapeutic interventions. We investigated characteristics of HDFN due to M/N-incompatible pregnancies in Japan after encountering a case of severe HDFN along with late-onset anemia in an infant born to a woman carrying IgG anti-M with a titer of 1. In total, thirty-three babies with HDFN due to anti-M and one due to anti-N have been reported in Japan since 1975. The median maternal antibody titer was 64 at delivery and was 16 or less in 10 of 34 women (29%). Five of 34 babies (15%) were stillborn or died as neonates. Twenty-one of 29 survivors (72%) had severe hemolytic anemia and/or hydrops fetalis. The reticulocyte count of neonates with anemia stayed below the reference interval. Sixteen (55%) developed late-onset anemia and 14 (48%) were transfused with M-negative RBCs. Significant positive correlation (P < .05) between the hemoglobin value and the reticulocyte count within 4 days of birth was obtained in 16 babies with anti-M HDFN. In the Japanese population, 21 of 34 cases of M/N-incompatible HDFN (72%) have manifested as severe hemolytic anemia and/or hydrops fetalis. Low reticulocyte count in neonates with late-onset anemia is consistent with suppressed erythropoiesis due to anti-M.

Maternofetal transplacental transport of recombinant IgG antibodies lacking effector functions

The neonatal Fc receptor (FcRn) directs the transfer of maternal immunoglobulin G (IgG) antibodies across the placenta and thus provides the fetus and newborn with passive protective humoral immunity. Pathogenic maternal IgG antibodies will also be delivered via the placenta and can cause alloimmunity, which may be lethal. A novel strategy to control pathogenic antibodies would be administration of a nondestructive IgG antibody blocking antigen binding while retaining binding to FcRn. We report on 2 human IgG3 antibodies with a hinge deletion and a C131S point mutation (IgG3ΔHinge) that eliminate complement activation and binding to all classical Fcγ receptors (FcγRs) and to C1q while binding to FcRn is retained. Additionally, 1 of the antibodies has a single point mutation in the Fc (R435H) at the binding site for FcRn (IgG3ΔHinge:R435H). We compared transplacental transport with wild-type IgG1 and IgG3, and found transport across trophoblast-derived BeWo cells and ex vivo placenta perfusions with hierarchies as follows: IgG3ΔHinge:R435H>wild-type IgG1≥IgG3ΔHinge and IgG3ΔHinge:R435H=wild-type IgG1=wild-type IgG3>>>IgG3ΔHinge, respectively. Collectively, IgG3ΔHinge:R435H was transported efficiently from the maternal to the fetal placental compartment. Thus, IgG3ΔHinge:R435H may be a good candidate for transplacental delivery of a nondestructive antibody to the fetus to combat pathogenic antibodies.

Development of Anti-G, Anti-C and Anti-Jk(b) in a 22-Year-Old Mother during Her Fourth Pregnancy

BACKGROUND

Anti-G antibodies are rarely found since anti-D, in combination with anti-C, are difficult to discriminate from anti-G antibodies in routine testing.

CASE REPORT

A 22-year-old, gravida-3, para-1, woman with blood group A Rh D neg ccddee and known antibody anti-Jk(b), gave birth to her second child. While anti-Jk(b) could not be detected at birth, a new anti-C was found. Antibody screening tests (IAT) were performed using gel cards and rare G positive rGr erythrocytes. Genotyping for RHD and RHCE was performed using PCR-SSP.

RESULTS

The child's blood group was A Rh D neg Ccddee. Genotyping revealed Cde/cde haplotypes. The erythrocytes of the new-born showed a positive direct antiglobulin test with IgG; anti-D and anti-C could be eluted. Erythrocytes with the rare phenotype rGr were reactive with the serum of the mother.

CONCLUSION

The presence of anti-D and anti-C in the eluate from then newborn's Ccddee erythrocytes proved anti-G or anti-G in combination with anti-D. When anti-C and anti-D are seen during a pregnancy, possibly anti-G is present. This observation is of relevance since women with anti-G can still develop anti-D and require rhesus prophylaxis.

A case of alloimmune thrombocytopenia, hemorrhagic anemia-induced fetal hydrops, maternal mirror syndrome, and human chorionic gonadotropin-induced thyrotoxicosis

Fetal/neonatal alloimmune thrombocytopenia (FNAIT) can be a cause of severe fetal thrombocytopenia, with the common presentation being intracranial hemorrhage in the fetus, usually in the third trimester. A very unusual case of fetal anemia progressed to hydrops. This was further complicated by maternal Mirror syndrome and human chorionic gonadotropin-induced thyrotoxicosis. Without knowledge of etiology, and possibly due to associated cardiac dysfunction, fetal transfusion resulted in fetal demise. Subsequent testing revealed FNAIT as the cause of severe hemorrhagic anemia. In cases with fetal anemia without presence of red blood cell antibodies, FNAIT must be ruled out as a cause prior to performing fetal transfusion. Fetal heart may adapt differently to acute hemorrhagic anemia compared with a more subacute hemolytic anemia.

Next-generation sequencing: proof of concept for antenatal prediction of the fetal Kell blood group phenotype from cell-free fetal DNA in maternal plasma

BACKGROUND

Maternal immunization against KEL1 of the Kell blood group system can have serious adverse consequences for the fetus as well as the newborn baby. Therefore, it is important to determine the phenotype of the fetus to predict whether it is at risk. We present data that show the feasibility of predicting the fetal KEL1 phenotype using next-generation sequencing (NGS) technology.

STUDY DESIGN AND METHODS

The KEL1/2 single-nucleotide polymorphism was polymerase chain reaction (PCR) amplified with one adjoining base, and the PCR product was sequenced using a genome analyzer (GAIIx, Illumina); several millions of PCR sequences were analyzed.

RESULTS

The results demonstrated the feasibility of diagnosing the fetal KEL1 or KEL2 blood group from cell-free DNA purified from maternal plasma.

CONCLUSION

This method requires only one primer pair, and the large amount of sequence information obtained allows well for statistical analysis of the data. This general approach can be integrated into current laboratory practice and has numerous applications. Besides DNA-based predictions of blood group phenotypes, platelet phenotypes, or sickle cell anemia, and the determination of zygosity, various conditions of chimerism could also be examined using this approach. To our knowledge, this is the first report focused on antenatal blood group determination using NGS.

High risk of transfusion-induced alloimmunization of patients with inflammatory bowel disease

BACKGROUND

Anemia is highly prevalent in inflammatory bowel disease patients, and red blood cell transfusion is often indicated already at reproductive age. Both transfusion and pregnancy may induce red cell alloantibodies, potentially complicating further transfusions and pregnancies. As recent evidence suggests that inflammation may promote red cell antibody induction, the alloimmunization risk of these patients after allogenic erythrocyte exposure was investigated.

METHODS

Red cell alloantibody status and clinical data were analyzed in 193 inflammatory bowel disease patients with a history of transfusion or pregnancy, and compared with transfused controls with noninflammatory diseases (n=357).

RESULTS

In transfused patients with inflammatory bowel disease, a 2.5-fold-increased red cell antibody prevalence was found (10/119, 8.4%), compared with transfused sex-matched controls with noninflammatory diseases (12/357, 3.4%; P=.023). Patients with inflammatory bowel disease had fewer transfusions (mean 3.0 vs 4.2, P=.003) but higher C-reactive protein levels during transfusion than controls (mean 8.4 vs 5.4 mg/dL, P <.001). The red cell antibodies of inflammatory bowel disease patients were clinically significant, directed against different Rh, Kell, Duffy, or Lutheran blood group antigens, and associated with higher number of transfusions (odds ratio 1.57; 95% confidence interval, 1.03-2.39). Conversely, immunomodulatory therapy during transfusion showed negative association (odds ratio 0.12; 95% confidence interval, 0.02-0.61). Only 1.4% of inflammatory bowel disease patients with pregnancy alone had antibodies.

CONCLUSIONS

Patients with inflammatory bowel disease exhibited a very high risk of transfusion-induced red cell alloimmunization, possibly potentiated by inflammation. Aside from a restrictive transfusion strategy, the implementation of prophylactic blood group phenotype matching of red cell concentrates (not only for ABO and RhD but also RhCcEe, Kell, Kidd, Duffy) could prevent antibody induction and associated complications in these patients.

[Management of feto-maternal red cell allo-immunizations]

Feto-maternal red cell alloimmunization is defined by the presence in a pregnant woman of alloantibodies directed against blood group antigens present on the red blood cells of the fetus and inherited from the father. It arises from the immune response to a first contact to these same antigens during a prior transfusion, transplant or pregnancy. The placental transfer and the fixation of the antibodies on the fetal red cells antigenic targets lead to a haemolysis in the fetus and the newborn. The resulting haemolytic disease can show different clinical forms, from a mild anaemia with neonatal hyperbilirubinemia to a major fetal damage with stillbirth caused by hydrops fetalis. The objective of management strategies of feto-maternal alloimmunization is to detect and monitor maternal alloimmunization and to appreciate the effects on the fetus or the newborn. Since a few years, some new non-invasive techniques of surveillance are used, for instance fetal RHD genotyping on maternal plasma and evaluation of fetal anaemia through velocimetry measurement of the blood flow in the middle cerebral artery. The need for a careful postnatal surveillance has to be emphasized due to the neonatal anaemia, which can be prolonged, and to the resurgence of cases of severe neonatal icteruses recently reported by the Académie de Médecine. The policy of prevention of anti-RH1 alloimmunization should also benefit from the evolution of biological techniques by allowing an improved targeting of concerned women.