A comparison of in vitro tests for predicting the severity of haemolytic disease of the fetus and newborn

Effect of intravenous immunoglobulins to postpone the gestational age of first intrauterine transfusion in very severe red blood cell alloimmunization: A case-control study

BACKGROUND

Early intrauterine transfusion (IUT) is associated with a higher risk of fetal loss. Our objective was to evaluate the efficiciency of intravenous immunoglobulins (IVIG) to postpone the gestational age at first IUT beyond 20 weeks of gestation (WG) compared to the previous pregnancy in case of very severe red blood cell (RBC) alloimmunization.

STUDY DESIGN AND METHODS

Very severe RBC alloimmunization was defined by a high titer of antibodies and a previous pregnancy complicated by a first IUT before 24 WG and/or perinatal death directly related to alloimmunization. We performed a single-center case-control study. Cases and controls were patients respectively treated with weekly IVIG infusions started before 13 WG, and without.

RESULTS

Twenty cases and 21 controls were included. Gestational age (GA) at first IUT was postponed after 20 WG in 18/20 (90 %) of patients treated with IVIG and in 15/21 (71 %) in the control group (p = 0.24). Compared to the previous pregnancy, the GA at first IUT was postponed by a median of 22 [+11; +49] days in the IVIG group and occurred in average 2 days earlier [-17 ; +12] in the non-treated group (p = 0.02). There was no difference between number of IUT and need for exchange-transfusion. IVIG treatment was associated with a significant decrease of antibodies' quantitation.

CONCLUSION

In our series, IVIG tends to differ first IUT beyond 20 WG and have a significant effect in postponing the gestational age of the first IUT in patients with very severe RBC alloimmunization.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Distribution of Kell phenotype among pregnant women in Sokoto, North Western Nigeria

Introduction

Kell antigen is highly immunogenic and is the common cause of antibody production in mismatched blood transfusions, haemolytic transfusion reaction (HTR) and maternal alloimmunization, which causes severe anaemia in neonates. The aim of this study is to determine the prevalence and ethnic variation of the Kell phenotype among pregnant women in Sokoto, Nigeria.

Methods

Kell antigen status of 150 pregnant women aged 18-45 years and mean age 27.19 ±4.69 years attending antenatal clinic in UDUTH Sokoto Nigeria was determined using the conventional tube method and anti-Kell reagents (Lorne Laboratories, UK).

Results

Among the 150 subjects studied, 3 (2.0%) of subjects were positive and 147 (98.0) were negative for K antigen. Of the 150 pregnant subjects; 32 (21.3%) were primigravidae while 118 (78.7%) were multigravidae. Kell phenotype was more prevalent among primigravidae (3.1%) compared to multigravidae (1.7%) women. The distribution of Kell phenotype among the pregnant subjects was compared based on ethnicity. The prevalence of Kell antigen was significantly higher among the Hausa ethnic group (3.2%) compared to other ethnic groups which indicated zero prevalence (p = 0.001). Kell negative phenotype was ≥ 96.8% among all the ethnic groups.

Conclusion

Our observed prevalence of Kell phenotype is consistent with previous studies among Blacks and Asians but significantly lower than values observed in previous studies among Caucasians. We recommend that all pregnant women should be screened for the presence clinically significant red cell antigens including Kell antigen on their first antenatal visit. Kell negative red cell should be routinely provided for all pregnant women and women with child bearing potential to reduce the risk of Kell-associated HDFN. There is need to introduce routine screening of pregnant women for clinically significant red cell antibodies to facilitate the effective management of HDFN as well as prevent HTR. There is also need for sustained health education of pregnant women in the area to encourage early booking for antenatal care.

Hemolytic disease of the fetus and newborn caused by anti-D and anti-S alloantibodies: a case report

Introduction

Hemolytic disease of the fetus and newborn is most commonly caused by anti-D alloantibody. It is usually seen in Rhesus D (RhD)-negative mothers that have been previously sensitized. We report here a case of hemolytic disease of the fetus and newborn in a newborn baby caused by anti-D and anti-S alloantibodies, born to a mother who was RhD negative, but with no previous serological evidence of RhD alloimmunization.

Case presentation

A one-day-old Chinese baby boy was born to a mother who was group A RhD negative. The baby was jaundiced with hyperbilirubinemia, but with no evidence of infection. His blood group was group A RhD positive, his direct Coombs' test result was positive and red cell elution studies demonstrated the presence of anti-D and anti-S alloantibodies. Investigations performed on the maternal blood during the 22 weeks of gestation showed the presence of anti-S antibodies only. Repeat investigations performed post-natally showed the presence of similar antibodies as in the newborn and an anti-D titer of 1:32 (0.25 IU/mL), which was significant. A diagnosis of hemolytic disease of the fetus and newborn secondary to anti-D and anti-S was made. The baby was treated with phototherapy and close monitoring. He was discharged well after five days of phototherapy.

Conclusions

This case illustrates the possibility of an anamnestic response of allo-anti-D from previous sensitization in a RhD-negative mother, or the development of anti-D in mid-trimester. Thus, it highlights the importance of thorough antenatal ABO, RhD blood grouping and antibody screening, and if necessary, antibody identification and regular monitoring of antibody screening and antibody levels for prevention or early detection of hemolytic disease of the fetus and newborn, especially in cases of mothers with clinically significant red cell alloantibody.

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

BACKGROUND

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

AIMS

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

SETTINGS AND DESIGN

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Étude quantitative des sous-classes d’IgG anti-D par Élisa au cours de la maladie hémolytique néonatale

The quantification of IgG anti-D subclasses is one of the most important parameters considered in the assessment of the severity of hemolytic disease of the newborn. Traditionally IgG subclassing is performed using qualitative haemagglutination methods, difficult to interpret. A quantitative enzyme-linked immunosorbent assay (Elisa) was implemented for measuring IgG anti-D subclasses in 20 sera collected from 14 RhD-immunized pregnant women. All 4 IgG subclasses were detected in the 20 sera tested. The mean proportion of IgG1 was 52.8%. The mean proportion of IgG3 was 30.7%. The mean proportions of IgG2 and IgG4 were 14.5 and 1.9% respectively. A good correlation between the sum of IgG subclasses and the severity of HDN was found. Severe HDN occurred when both IgG1 and IgG3 were present. IgG1 anti-D was the predominant subclass in 4 of the 8 severe cases.

Anti-E alloimmunization in pregnancy: management dilemmas

Compared to anti-D alloimmunization, anti-E alloimmunization is a less common cause of hemolytic diseases of the newborn. Being a less potent immunogen, clinical manifestations of anti-E alloimmunization are more variable and usually of less severity. However, the clinical obstetric management of these cases of anti-E alloimmunization is just as challenging. We report here the management of a patient with anti-E alloimmunization to illustrate the controversies of invasive and non-invasive monitoring in the management of such cases.

IgG1 and IgG3 anti-D in maternal serum and on the RBCs of infants suffering from HDN: relationship with the severity of the disease

BACKGROUND

Anti-D IgG antibodies that are responsible for severe cases of HDN belong chiefly to IgG1 and IgG3 subclasses. The relationship between the concentrations of IgG1 anti-D and IgG3 anti-D in maternal serum and the amount bound to the surface of infants' RBCs is not known. In addition, the contribution of the two subclasses to the severity of HDN is not well established.

STUDY DESIGN AND METHODS

Blood samples from 40 infants suffering from severe forms of HDN due to anti-D were collected before transfusion together with sera from their respective mother. The amount of total anti-D IgG as well as IgG1 anti-D and IgG3 anti-D on infants' RBCs and the concentration in maternal sera were determined by ELISA.

RESULTS

The median percentages of IgG1 anti-D and of IgG3 anti-D in maternal sera were 90 and 10 percent, respectively, whereas on infants' RBCs they were 97 and 3 percent, respectively. The differences between maternal and infantile percentages were significant (p < 0.001). IgG1 and IgG3 anti-D bound to infants' RBCs increased concomitantly with the concentration of IgG1 and IgG3 anti-D in maternal sera. The severity of HDN correlated positively with the concentration of IgG1 anti-D in maternal sera, but negatively with the amount of IgG3 anti-D bound to infants' RBCs. In addition, the existence of a high proportion of IgG3 anti-D in maternal serum was associated with a delayed risk of fetal anemia.

CONCLUSION

The proportion of IgG3 anti-D relative to the total anti-D IgG on infants' RBCs is only one- third of the proportion present in maternal serum. The study of the correlations between the amount of IgG1 anti-D and IgG3 anti-D and the severity of HDN suggests that IgG1 anti-D are more important than IgG3 anti-D in the pathogenesis of fetal anemia.

Prenatal RHD gene determination and dosage analysis by PCR: clinical evaluation

BACKGROUND

Use of the polymerase chain reaction (PCR) for detection of the RHD gene can measure the RHD gene status for unborn babies at risk for hemolytic disease of the newborn (HDN). The occurrence of D gene variants has led to errors in prenatal typing. Previous reports have highlighted the danger of assigning a positive fetus as negative, resulting in intrauterine fetal deaths.

OBJECTIVE

To evaluate the effectiveness of a testing strategy whereby PCR was not only performed to determine the presence/absence of the RHD gene, but also used to assess the D gene copy number (zero, one or two RHD genes) in family studies for at risk pregnancies.

METHODS

Samples comprising maternal (57) and paternal (42) peripheral blood samples, amniotic fluid (64), and matching cord blood (64) were collected. Rhesus (Rh) serotyping was performed on all blood samples. For RHD genotyping, DNA was extracted from all samples except for 28 cord samples, where only serotyping was performed (total 199 DNA genotyping). RHD gene PCR amplified exon 4 and exon 7 regions of the RHD gene. The dosage of RHD gene was determined by comparing the intensity of the RHD gene to that of the RHCE gene.

RESULTS

A total of 197/199 samples showed concordance between exon 4 and exon 7 PCR results. Two discrepant results occurred in one family: the father carried one normal D gene and one D gene variant where PCR was tested to be positive using exon 4 but negative using exon 7. One of a pair of dizygotic twins inherited this abnormal D gene and was mildly affected by HDN. This was correctly identified antenatally and the pregnancy successfully managed. The concordance rate between serotypes and genotypes for 135 blood samples was 100%. Amongst the family groups, 8/14 heterozygous fathers transmitted the D gene and 26/26 homozygous fathers transmitted the D gene to the babies. The concordance rate between RHD genotypes from amniotic fluid and Rh D serotypes from cord blood was also 100%.

CONCLUSION

The present study demonstrates the effectiveness of using PCR in a clinical setting. It verifies the importance of testing more than one region of the gene, and also the need for a testing strategy where both maternal and paternal testing for RHD gene dosages are performed.

An overview of the use of flow cytometry in the analysis of mixed red cell populations

This paper reviews the application of flow cytometric techniques to the analysis and quantitation of mixed red cell populations. Such mixtures may arise in a variety of ways, for example: through transplacental hemorrhage during pregnancy or upon delivery; through iatrogenic procedures such as blood transfusion, bone marrow or peripheral blood stem cell transplantation; or through disease, when a loss of surface antigen expression may occur due to the expansion of abnormal progenitors lacking the appropriate gene or lacking the ability to translate the product of the gene. Flow cytometry can offer a simple and accurate means of identifying and quantitating mixed red cell populations through detection of antigens specific for either donor or recipient, and in many cases it is possible to distinguish homo- or heterozygous expression of a common antigen. Internal antigens may be accessed after fixation and permeabilisation of the red cells. These latter techniques are relatively new and expand the spectrum of antigenic differences available for the identification of individual species in mixed populations.