A case for comprehensive antenatal screening for blood group antibodies

OBJECTIVES

To determine the frequency of various blood group antibodies responsible for haemolytic disease of the new born (HDN).

DESIGN

A prospective study of all neonates and still born foetuses suspected to have haemolytic disease of the new born and their mothers.

SUBJECTS

Neonates suspected to have HDN as per study criteria along with their mothers and mothers of still born foetuses with hydrops foetalis.

METHODS

Pertinent serological tests, serum bilirubin estimation, haemoglobin estimation and reticulocyte count on neonate's blood samples and demonstration/titration of blood group specific antibodies in maternal blood samples.

RESULTS

Six cases of HDN due to blood group antibodies were detected so far. Four were due to anti-D and all were of mild severity as per study criteria. Two cases were of severe haemolytic disease (hydrops foetalis). Both were due to anti Kell. Both women had history of previous blood transfusion and abortions.

CONCLUSION

Comprehensive antibody screening should be performed during antenatal period in women who have received blood transfusion and/or have history of un-explained abortions.

[Prenatal typing of Rh- and Kell- blood group system antigens]

Rhesus (Rh) and Kell blood group immunisations are the most frequent causes of haemolytic disease of the newborn. Recently, the molecular bases of the Rh and Kell antigens have been elucidated. Subsequently, specific polymerase chain reactions (PCRs) could be developed to determine the RhD, RhC/Rhc and RhE/Rhe genotypes as well as the KI genotype (from the Kell blood group) with genomic DNA. The tests were applied to genomically determine the foetal Rh and Kell blood groups with DNA obtained from amniotic fluid cells. The genotypes obtained were compared with the Rh phenotypes established by cord blood red cell serology. The PCRs to determine the RhD, Rhc, RhE and Rhe and KI genotypes were found to be reliable. The test for RhC however, resulted in false-positive C genotypes. Indeed, more than half of the subsequently tested C-negative Negroid donors were false-positive with the DNA test. Thus, except for RhC, it is possible to reliably determine the Rh and KI genotypes of a foetus with DNA isolated from amniotic fluid cells. Amniocentesis, however, carries a risk for the pregnancy and therefore the tests will only be justified in pregnant women in whom an antibody has been detected and the father of the foetus is heterozygous for the specific antigen. Recently foetal RhD genotypes were determined in foetal DNA circulating in the plasma of RhD-negative pregnant women. This could eventually lead to the introduction of assays with which the foetal blood group can be determined without any risk to the foetus.

[Two neonates with severe rhesus antagonism inspite of low values in recent tests of antibody dependent cellular cytotoxicity (ADCC)]

In two female newborn babies severe haemolytic disease of the newborn developed due to anti-RhD antibodies of the mother. In both cases the results of the last antibody-dependent cellular cytotoxicity (ADCC) test had been < 10% (two and three weeks before parturition respectively) making haemolytic disease unlikely. The ADCC test is used to determine the destructive power of the responsible maternal antibodies. It is believed that with a low ADCC value (< 10%), there is no danger of clinically relevant haemolytic disease. The first neonate recovered after exchange transfusion, the second died notwithstanding extensive supportive therapy. A recent low ADCC value makes serious haemolytic disease unlikely, but does not completely exclude it, as the titre of the causative antibodies can rise very quickly.

[Risk management program in a health facility using a project approach: transfusion risk management]

Risk management in the hospital, which is one of the referentiels of the ANAES accreditation manual, may be considered on two levels. Firstly, risk management may be approached globally, in the same way as it is tackled in the accreditation process. Secondly, risk management may be more definite. A specific risk chosen in accordance with the priorities of a particular plan may be dealt with individually. In this respect, the tranfusion process allows the risk management method to be tested and developed. f1

[Irregular blood group antibodies during pregnancy: screening is mandatory]

During pregnancy irregular blood group antibodies, originating either from earlier pregnancies or from blood transfusions, may severely jeopardize both mother and child. Three patients are described with pregnancy-associated blood group incompatibility. In one case of Kell antagonism a previous child had reportedly died of cot death, but in retrospect it had most probably suffered from erythroblastosis fetalis as a result of anti Kell antibodies. In the second case, a twin pregnancy, the diagnosis of neonatal haemolytic anaemia on the basis of blood group incompatibility with a very rare antibody (anti-Kpb) had been established in the previous child. No precautions had been taken during this pregnancy, putting both mother and children at risk. All three children recovered, the twins after repeated transfusion of Kpb-free erythrocytes. The described cases emphasize the importance of being informed about the presence of antibodies during pregnancy. Such information can only be obtained by assessing the antibody status during pregnancy. In the Netherlands, the screening of all pregnant women for the presence of irregular antibodies was introduced last year.

Fading kitten syndrome and neonatal isoerythrolysis

Fading kitten syndrome includes noninfectious and infectious causes for neonatal death (birth to weaning age). Noninfectious causes are mostly responsible for mortality in the first week of life and include congenital disorders, low birth weights, trauma, malnutrition, environmental causes, and neonatal isoerythroylsis. Infectious causes are more prevalent at 3-4 weeks of age. This article discusses the causes, clinical signs, and management of fading kitten syndrome.

Management of pregnancies complicated by anti-Kell isoimmunization

OBJECTIVE

To assess the efficacy of managing pregnancies complicated by anti-Kell isoimmunization using the methods developed for evaluating anti-Rh-D isoimmunization.

METHODS

We reviewed 156 anti-Kell-positive pregnancies seen from 1959 to 1995, which were managed with serial maternal titers, amniotic fluid deltaOD450 determination, and funipuncture. Data on maternal titers, paternal phenotypes, invasive fetal testing and therapies, and neonatal outcomes were collected and analyzed to determine whether severely affected pregnancies were identified in time for successful fetal and neonatal therapy.

RESULTS

Twenty-one fetuses were affected, eight with severe disease, and two fetuses in this group died. All of the severely affected fetuses were associated with maternal serum titers of at least 1:32. A critical titer of 1:32 was found to be 100% sensitive for identifying the affected pregnancies. The affected group had significantly higher amniotic fluid deltaOD450 values over the range of gestational ages than did the unaffected group (P < .001). The upper Liley curve was a specific discriminator for the diagnosis of affected fetuses, and the lower curve was specific for the diagnosis of unaffected or mild cases.

CONCLUSION

Fetal anemia due to anti-Kell isoimmunization might be due in part to erythropoietic suppression, but it is still largely a hemolytic process. The methods based on a hemolytic process, including use of a critical maternal serum titer of 1:32, serial amniotic fluid analyses when the titer was exceeded, and liberal use of funipuncture, were successful in identifying severely affected fetuses.

Prenatal genotyping of the Duffy blood group system by allele-specific polymerase chain reaction

Maternal allo-immunization to antigens of the Duffy blood group system can result in haemolytic disease of the newborn (HDN), therefore, the application of allele-specific polymerase chain reaction (ASPCR) for prenatal genotyping of the Duffy antigen system to identify pregnancies at risk for HDN was evaluated. Oligonucleotide primers were designed for ASPCR of FYA, FYB and nullFY alleles. A validation study was performed using DNA isolated from 94 serotyped whole blood samples and 8 amniocentesis samples. A concordance rate of 100 per cent was observed between serotyping and ASPCR detection of the FYA, FYB and nullFY alleles. This assay is particularly useful for rapid genotyping of fetal amniotic cells to identify pregnancies at risk for HDN due to maternal fetal incompatibilities within the Duffy blood group system.

[Final bedside verification: results of a national survey of reagents and devices used in France]

The national reference Center for blood groups checked samples of reagents and devices used in France for a definitive verification of pretransfusion ABO tests performed at the patient's bedside, as defined by French health authority regulations. The results of an initial inquiry was published in 1991. The new study shows no significant improvement of the quality of reagents and devices. This is a major concern considering the importance of ABO incompatibility in severe hemolytic transfusion reactions.

Reliability of the pretransfusion bedside compatibility test: association with transfusion practice and training

BACKGROUND

The utility of a pretransfusion bedside blood compatibility protocol to decrease immunohemolytic accidents has been questioned for years.

STUDY DESIGN AND METHODS

The reliability of a standard bedside ABO compatibility test was evaluated with a stratified random sample of 48 nurses who performed agglutination testing by using Bristol cards, interpreted compatibility, and decided whether to transfuse red cells for 12 randomly and blindly selected donor-and-recipient blood sample pairs. An expert judged technical performance and the interpretation of each card.

RESULTS

Erroneous decisions occurred in 18.2 percent of 576 tests, including 12 decisions to transfuse incompatible blood. Errors involved both testing protocols and the interpretation of compatibility. Anti-A and anti-B were detected with 92.8-percent sensitivity and 95.9-percent specificity. The expert judged 17.7 percent of tests to be technically inadequate, most often because of the application of excess blood to the card and a lack of rotation of the card. Testing errors (16.1% of tests) were significantly linked to infrequent transfusion activity by the nursing service, inexperience, and insufficient training. Compatibility misinterpretation occurred in 14.6 percent of the tests and was significantly linked to the nurses' infrequent transfusion activity, inexperience, insufficient training, lack of practical experience, and confusion regarding the use of ABO-compatible but not identical blood.

CONCLUSION

Bedside pretransfusion compatibility determination should not be considered a reliable supplemental safety procedure in the hands of inexperienced and insufficiently trained operators.

Detection of high risk pregnancies with relation to ABO haemolytic disease of newborn

IgM and IgG anti A and anti B antibody status of 100 antenatal O group mothers (who had non O group husbands) were studied. Of these, 3 mothers had an IgM anti A antibody levels ranging from 1:512 to 1:2048 and IgG ranging from 1:1204 to 1:2048, IgM anti B ranging from 1:128 to 1:512 and IgG anti B ranging from 1:256 to 1:512. All these mothers had A + ve children and all these children suffered from ABO haemolytic disease of newborn (HDN). A 4th mother had an IgM anti A titre of 1:64 and IgG anti A titre of 1:16. The titre of IgM anti B in this mother was 1:512 and that of IgG 1:1024. The child was A + ve and did not suffer from ABO haemolytic disease of newborn.

[Evaluation of the polyethyleneglycol antiglobulin test in the detection and identification of erythrocyte antibodies]

PURPOSE

The polyethylene glycol antiglobulin test has been found to enhance the reactivity of most alloantibodies.

MATERIAL AND METHODS

To investigate the utility of polyethylene glycol antiglobulin test for detection and identification of red blood cell antibodies, a comparison study of polyethylene glycol (PEG), a low-ionic-strength additive solution (LISS) and bovine serum albumin (BSA) was conducted. The sera of 47 different patients with positive antibody screening test by the LISS method, were tested in parallel with reagent antibody-detection cells using PEG, LISS and BSA.

RESULTS

In the sera of 47 patients, 57 antibodies were detected. We identified 39 antibodies by the three methods. Twelve antibodies reacted by the BSA method and the LISS method but did not react with the PEG method (8 anti-I, 1 anti-P1, 1 anti-Lea(a), and two antibodies missed by the PEG method because they did not react with anti-IgG: 1 anti-M and 1 anti-K). Three antibodies reacted only with the LISS method (3 anti-I). Four clinically significant antibodies were detected only by the PEG method (2 anti-Jka, 1 anti-Jkb, 1 anti-c). The serum from a patient with delayed hemolytic transfusion reaction and no antibody detectable by the LISS and the BSA methods was tested by the PEG method. We were able to detect an anti-Jka by PEG in the pretransfusion sample. In 24 (60%) of 40 samples with clinically significant antibodies, PEG antiglobulin reactions were stronger (total score 221) than LISS antiglobulin reactions (total score 170) and BSA antiglobulin reaction (total score 184); in 14 (35%) of 40 samples, they were identical, and in 2 (5%) agglutination in the PEG method was weaker.

CONCLUSION

In our experience, the polyethylene glycol antiglobulin test is more sensitive than LISS and BSA in detecting clinically significant antibodies and is an acceptable technique for routine compatibility test.

Limits of the MAIPA assay when differentiating high-titered platelet-reactive antibodies

Experience with the MAIPA assay for the diagnosis of platelet-reactive antibodies has shown that high-titered antibodies falsify the test results. We here demonstrate 2 cases: i) A serum with high-titered HLA antibodies (100% panel reactivity in the LCT, titer between 4,000 and 12,000), and ii) Serum with a high-titered anti-HPA-1a (titer in the MAIPA assay 1,000). In both cases, it can be demonstrated that these antibodies led to unspecific reactions. In the 1st case, they interfered with the diagnosis of additional platelet-specific antibodies. Only the use of HLA-compatible platelets allowed a correct identification. On the other hand, in the high-titered anti-HPA-1a unspecific reactions were seen with the glycoproteins Ib/IX, Ia/IIa, and beta 2-microglobulin, leading to misinterpretations. These examples demonstrate that, in the test conditions as described, a correct diagnosis of high-titered sera might only be achieved by using compatible HLA or HPA cells.

Rapid donor type isoagglutinin production after allogeneic peripheral progenitor cell transplantation

Signs of haemolysis and donor-type isoagglutinin production were observed in a patient with minor ABO incompatibility following peripheral progenitor cell transplantation with posttransplant cyclosporine for GvHD prophylaxis. Renal failure was avoided by immediate forced diuresis.

The benefit of the direct antiglobulin test using gel technique in ABO hemolytic disease of the newborn

The direct antiglobulin test (DAT) using the gel technique was included in the investigation of infants with hyperbilirubinemia in the first week of life. Twelve cases were preterm and 48 cases were full term infants. The patients were divided into 2 groups: the study group comprised 22 cases of blood group A or B infants born to blood group O mothers; the control group comprised 38 cases of ABO blood groups compatible with those of their mothers. The mean +/- SD (39 +/- 26 hours) of the age at the onset of hyperbilirubinemia induced by ABO hemolytic disease of the newborn (HDN) was significantly earlier than that due to other causes. The positive rate of DAT in the ABO incompatible group was similar by both the conventional technique and the gel technique, 54.5% and 50% respectively. However, the scores by the gel technique were higher than those of the conventional technique. The gel technique is simple, reliable, involves less technical error and requires a small amount of blood sample. The grading system is clear-cut, especially grade 1 + or weak positive as compared to the conventional technique which requires examination under a microscope. Therefore, the DAT using the gel technique is beneficial to the diagnosis of ABO HDN. It should be included in the investigation of infants with hyperbilirubinemia especially in case of suspected ABO HDN.

[Hematological emergencies]

In this short review some important hematologic emergencies, that have been discussed at a round table on the occasion of the 22, meeting of internal medicine in central Switzerland are outlined without intention to be complete. The following emergencies are featured: Anemia, increased hematocrit (polyglobulia), severe (unexpected) neutropenia, marked hyperleukocytosis and leukemias, severe thrombocytopenia; thrombocytopathies (hereditary or acquired), von Willebrand-disease, acquired or hereditary coagulation disorders (coagulopathies), acute venous thrombosis; acute hemolytic transfusion reaction, posttransfusion purpura, severe autoimmune hemolysis.