Red cell alloimmunization in RhD positive pregnant women and neonatal outcome

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

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

Distribution and frequency of principal Rh blood group antigens (D, C, c, E, and e) and their phenotypes in the blood donors attending blood bank in a tertiary care hospital in Barpeta district of Assam

BACKGROUND

The ABO and Rhesus grouping system antigens have been found to have the highest immunogenicity and propensity to produce alloantibodies that cause most of the transfusion reactions. The Rhesus antigens that produce most of the immunogenic transfusion reactions are D, C, c, E, and e. Knowledge of the distribution of these Rh antigens in a population helps to render compatible blood in alloimmunized patients.

AIM

The aim was to study the distribution and frequency of principal Rh blood group antigens (D, C, c, E, and e) and their phenotypes in the blood donors attending blood bank in a tertiary care hospital in Barpeta district of Assam.

MATERIALS AND METHODS

The study was conducted in 315 voluntary blood donors in the blood bank of a tertiary care center. Rh-D typing was done by conventional tube method. Specific monoclonal antisera, i.e., anti-C, anti-c, anti-E, and anti-e, were used and tests were performed by conventional tube method for detection of the presence of rest of the major Rh antigens.

RESULTS

The samples were analyzed for the five major Rhesus antigens. "D" antigen was found to be the most common antigen (99.05%), followed by e (97.14%), C (92.38%), c (51.43%), and E (20.95%). In order of descending frequency, the most common phenotypes were DCCee - 45.71%, DCcee - 30.48%, DCcEe - 11.43%, DccEe - 4.76%, DCcEE - 1.90%, DCCEe - 1.90%, Dccee - 1.90%, DCCEE - 0.95%, and dccee - 0.95%.

CONCLUSION

D antigen is the most common antigen in our study population, whereas "e" antigen is the most common in most of the studies done from other parts of India. Data on frequencies of major Rh antigens in the local donor population will help in transfusing alloimmunized patients with corresponding antibody-negative blood ensuring blood safety.

Neonatal and pediatric transfusion practices and policies in India: A survey-based cross-sectional assessment of blood centers

BACKGROUND

Blood centers play a critical role in supporting neonatal and pediatric transfusions. We aim to study the variation in pediatric/neonatal transfusion policies and practices for blood centers in India.

STUDY DESIGN AND METHODS

This is a survey-based (45 question) cross-sectional assessment of blood centers in India supporting pediatric/neonatal transfusions.

RESULTS

One hundred three centers responded to the survey (response rate 51.2%; 103/201). As a part of pretransfusion testing, use of "microtainers" was reported by 58.4% (59/101) centers and only 57.4% (58/101) centers provide antibody screening. In case of absence of maternal sample, type O negative blood is most commonly used (48.5%; 49/101), and in case of ABO incompatibility, 68.3% (69/101) use units compatible with both mother and newborn. Leukoreduced RBCs are provided by 89% (90/101) centers and irradiated products are provided by 48.5% (49/101). 82% (83/101) of centers reported not receiving requests for CMV negative units considering the high incidence of CMV-seropositivity in donors. Fresh units are defined as <7 days old by 44.5% (45/101) and <5 days old by 31.6% (32/101) centers. 97% centers reported SAGM suspended RBCs in inventory but only 67.3% (68/101) use them for top-up transfusions to neonates. Overall >80% centers use the buffy-coat method for platelet concentrates preparation. Volume-based (ml/kg) aliquots preparation is done by 88% (89/101), mainly using the sterile connecting device (84.6%; 83/98).

CONCLUSION

This survey shows heterogeneity and lack of standardization in practices across blood centers in India and highlights the need for more studies to establish best practices for this vulnerable age group.

Irregular erythrocyte antibodies among antenatal women and their neonatal outcome at a tertiary care hospital in Northern India

BACKGROUND

Red blood cell alloimmunisation during the pregnancy is a significant cause for neonatal mortality and morbidity. This study was planned to determine the prevalence and specificity of irregular erythrocyte antibodies in antenatal mothers and their neonatal outcome.

METHODS

In this observational study, blood grouping and red cell antibody screening of mothers were performed at first visit and after 28 weeks of gestation and positive cases were identified and followed up monthly till delivery by repeating antibody titre and middle cerebral artery-peak systolic velocity. After delivery of alloimmunised mothers, cord blood haemoglobin, bilirubin and direct antiglobulin tests (DAT) were analysed and further outcome of neonate was recorded.

RESULTS

Among 652 registered antenatal cases, 18 multigravida women were found to be alloimmunised, accounting to prevalence of 2.8%. Most common alloantibody identified was anti D (>70%) followed by anti-Le^a, anti-C, anti-Le^b, anti-E and anti-Jk^a. Only 47.7% Rh D negative women received anti-D prophylaxis during previous pregnancies or whenever indicated. DAT was positive in 56.2% of neonates. Among nine DAT positive neonates, two early neonatal deaths due to severe anaemia were observed following birth resuscitation. Four antenatal mothers required intrauterine transfusion in view of fetal anaemia while three neonates received double volume exchange transfusion and top up transfusions after birth.

CONCLUSIONS

This study emphasises importance of red cell antibody screening for all multigravida antenatal women at registration of pregnancy and additionally at 28 weeks or later in high-risk cases irrespective of RhD status.

Red cell alloimmunization among antenatal women attending tertiary care center in Jamnagar, Gujarat, India

BACKGROUND

The following study was conducted to measure the presence of alloantibodies of Rh and other blood group antigens produced due to fetomaternal hemorrhage in all antenatal women as well as those leading to hemolytic disease of fetus and newborn; presenting to a tertiary care center, G.G. Government Hospital, Jamnagar, Gujarat, India, between April 2014 and March 2016 (2 years).

MATERIALS AND METHODS

All multiparous women irrespective of their period of gestation or obstetrics history were included whereas those having taken anti-D immunoprophylaxis or with a history of blood transfusion were excluded. Antibody screening and identification were done using Bio-Rad ID microtyping system.

RESULTS

Out of total 8920 multigravida females, 8488 were D-antigen positive whereas 432 were D-antigen negative. A total of 126 antibodies among 117 females (1.31%) were found; out of them, 33 were found in D-antigen positive females (0.39%) and 84 in D-antigen negative ones (19.44%) looking at overall frequency of other antibodies such as anti-C: 9, anti-c: 9, anti-E: 13, anti-Cw: 1, anti-M: 5, anti-S: 8, anti-Fya: 3, and anti-D: 78; it was found that anti-D is the most common.

CONCLUSION

The rate of alloimmunization in D-antigen negative women was found to be very high as compared to other studies in western region; hence, strict follow-up of immunoprophylaxis of all Rh D-negative women needs to be taken care of. Apart from this, D-antigen-positive women also show alloimmunization against various antigens giving the prevalence of 0.39%; hence, it should be mandatory that there should be one standard universal protocol for screening of all antenatal women.

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

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

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.