Anti-Rh alloimmunization after trauma resuscitation

The AABB recently posted a bulletin (19-02) regarding their recommendations for the use of group O red blood cells (RBCs) during trauma. Though group O Rh(D)-negative RBC units are considered the 'safest', the demand of such units often exceeds the supply. Therefore, O Rh(D)-positive units are often used during the first parts of a massive transfusion protocol (MTP) or patients with particularly severe hemorrhage are switched over from O Rh(D)-negative to O Rh(D)-positive RBC units in order to preserve the O Rh(D)-negative supply. In light of these limitations, it is important to understand the risk of such policies to the patient. The reported risk of alloimmunization after exposure to Rh(D)-positive RBCs ranges widely from 3 to 70%. In response, we performed a retrospective review of 1,198 patients in our institution that had a MTP activation due to trauma. Of those patients, we focused on Rh(D)-negative patients that received at least 1 unit of Rh(D)-positive RBCs. Seventy-two patients met the criteria for inclusion, accounting for 6% of the total population. Of the 72 Rh(D)-negative patients, we identified 17% that formed new Rh group antibodies after exposure to Rh(D)-positive RBCS. All 10 of our alloimmunized patients (two of which were females of childbearing age) formed anti-D, while 3 patients also formed either anti-E or anti-C. Since this was a retrospective review, we did not perform repeated antibody screens for the entire study period, but did review all records for the entire period. We did note that we were more likely to detect an novel alloantibody if more antibody screens were performed during the patient's initial stay and during follow-up visits. We conclude that providing Rh(D) negative patients Rh(D) positive RBC units is not without risk and policies regarding such provisions should be carefully considered. As RBC shortages continue to be a part of daily practice, such issues may continue to be a challenge for the blood bank community.

Laboratory management of perinatal patients with apparently "new" anti-D

Despite the existence of long-standing, well-organized programs for Rh immune globulin (RhIG) prophylaxis, immune anti-D continues to be detected in the D– perinatal population. Between 2006 and 2008, 91 prenatal patients, found to have a previously unidentified anti-D, were followed up with a survey to their treating physician and with additional serologic testing where possible. The physician survey requested pregnancy and RhIG history information, including recent or distant potential alloimmunizing events, and the physicians were asked their opinion on the likely cause for the anti-D. Based on survey responses, updated RhIG information, and results of follow-up serology, anti-D was determined to be attributable to previously unreported RhIG in 44 of 91 (48.3%) cases and to active immunization (immune anti-D) in 36 of 91 cases (39.6%). A probable cause for alloimmunization was reported in 14 of 52 (26.9%) returned surveys. Anti-D alloimmunization continues to occur in our prenatal population despite a comprehensive approach to RhIG therapy. Observations from this prospective patient management strategy include the need for improved application of guidelines for RhIG administration and improved quality of information provided to laboratories assessing RhIG eligibility. A laboratory process for prospective follow-up when unexpected anti-D is detected in pregnancy is recommended.

Detection of fetomaternal hemorrhage

The prevention of Rhesus D alloimmunization through Rh immune globulin (RhIg) administration is the major indication for the accurate detection and quantification of fetomaternal hemorrhage (FMH). In the setting of D incompatibility, D-positive fetal cells can sensitize the D-negative mother, resulting in maternal anti-D alloantibody production. These anti-D alloantibodies may lead to undesirable sequelae such as hemolytic disease of the newborn (HDN). Since the widespread adoption of FMH screening and RhIg immunoprophylaxis, the overall risk of Rh alloimmunization and infant mortality from HDN has substantially decreased. The rosette screen, the initial test of choice, is highly sensitive in qualitatively detecting 10 mL of fetal whole blood in the maternal circulation. As the screen is reliant on the presence of the D antigen to distinguish fetal from maternal cells, it cannot be used to detect FMH in D-positive mothers or in D-negative mothers carrying a D-negative fetus. The Kleihauer-Betke acid-elution test, the most widely used confirmatory test for quantifying FMH, relies on the principle that fetal RBCs contain mostly fetal hemoglobin (HbF), which is resistant to acid-elution whereas adult hemoglobin is acid-sensitive. Although the Kleihauer-Betke test is inexpensive and requires no special equipment, it lacks standardization and precision, and may not be accurate in conditions with elevated F-cells. Anti-HbF flow cytometry is a promising alternative, although its use is limited by equipment and staffing costs. Hematology analyzers with flow cytometry capabilities may be adapted for fetal cell detection, thus giving clinical laboratories a potentially attractive automated alternative for quantifying FMH.

Molecular RH blood group typing of serologically D-/CE+ donors: the use of a polymerase chain reaction-sequence-specific primer test kit with pooled samples

The known presence of RHD blood group alleles in apparently D– individuals who are positive for C or E antigens leads to an appropriate investigation for the RHD gene on the red blood cells (RBCs) of D– blood donors, thus preventing their RBCs from immunizing D– recipients. Ready-to-use polymerase chain reaction–sequence-specific primer (PCR-SSP) typing kits are available and allow single-sample results. The need to perform this testing on a large number of donors affiliated with the Transfusion Department of Udine (Northern Italy) led to the use of molecular genetic RH blood group typing with PCR-SSP test kits and DNA samples mixed in pools. From a population of 35,000 blood donors screened for D antigen by serologic typing, a total of 235 samples, distributed in pools of 5 DNA samples, were investigated. Positive results were reevaluated by opening the pools and retesting single samples. Validation of DNA-pool typing with commercial kits was done. Among 235 genotyped samples, 12 were found to be PCR positive (5.1%), exhibiting DEL genotype and RHD-CE-D hybrid alleles. Our data demonstrate that the use of a PCR-SSP commercial test kit with pooled samples is a helpful and valid method to correctly detect RHD alleles. As a consequence, we reclassified our donors as carriers of potentially immunogenic alleles.

Risk factors for RhD immunisation despite antenatal and postnatal anti-D prophylaxis

OBJECTIVE

To identify risk factors for Rhesus D (RhD) immunisation in pregnancy, despite adequate antenatal and postnatal anti-D prophylaxis in the previous pregnancy. To generate evidence for improved primary prevention by extra administration of anti-D Ig in the presence of a risk factor.

DESIGN

Case-control study.

SETTING

Nation-wide evaluation of the Dutch antenatal anti-D-prophylaxis programme.

POPULATION

CASES

42 RhD-immunised parae-1, recognised by first-trimester routine red cell antibody screening in their current pregnancy, who received antenatal and postnatal anti-D Ig prophylaxis (gifts of 1000 iu) in their first pregnancy.

CONTROLS

339 parae-1 without red cell antibodies.

METHODS

Data were collected via obstetric care workers and/or personal interviews with women.

MAIN OUTCOME MEASURE

Significant risk factors for RhD immunisation in multivariate analysis.

RESULTS

Independent risk factors were non-spontaneous delivery (assisted vaginal delivery or caesarean section) (OR 2.23; 95% CI:1.04-4.74), postmaturity (>or=42 weeks of completed gestation: OR 3.07; 95% CI:1.02-9.02), pregnancy-related red blood cell transfusion (OR 3.51; 95% CI:0.97-12.7 and age (OR 0.89/year; 95% CI:0.80-0.98). In 43% of cases, none of the categorical risk factors was present.

CONCLUSIONS

In at least half of the failures of anti-D Ig prophylaxis, a condition related to increased fetomaternal haemorrhage (FMH) and/or insufficient anti-D Ig levels was observed. Hence, RhD immunisation may be further reduced by strict compliance to guidelines concerning determination of FMH and accordingly adjusted anti-D Ig prophylaxis, or by routine administration of extra anti-D Ig after a non-spontaneous delivery and/or a complicated or prolonged third stage of labour.

Transfusions de concentrés plaquettaires Rhésus incompatible au CHU de Rouen : pratiques et conséquences

INTRODUCTION

Guidelines for distribution and use of blood products have been established for both blood transfusion institution and hospitals, in particular for the use of Rh (D)-incompatible platelet concentrates. The aim of this study was to evaluate: 1) the rate of attribution for the Rh (D)-incompatible platelets concentrates, 2) the immunisation prophylaxis practices, 3) the immunological consequences using short and medium term follow-up of transfused patients.

METHODS

Patients with Rh (D)-incompatible platelets concentrate administered during the year 2003 at Rouen University Hospital were retrospectively selected. Patients on transfusion were described. The relationship of various factors with the injection as well as the appearance of allo-immunization was statistically tested.

RESULTS

During a year, 280 Rh (D)-incompatible platelets concentrates were administered to 67 patients. Immunisation prophylaxis by injection of Ig anti-D was not systematically performed. Four immunizations in the Rhesus group system were identified: 2 against D antigen (Ag), 1 against E Ag and 1 against C Ag. Immunisations against D Ag occurred for two younger women considered as immunodeficient. Immunization prophylaxis was more frequent in poly-transfused patients. However no difference was observed for the other factors.

CONCLUSION

Compatibility concerning Rhesus (D) is not always possible. The immunization against red cells persists, in particular against the antigens of the Rhesus group system and moreover for the immunodeficient patients. Recommendations for immunization prophylaxis by injection of specific anti-D immune-globulin (Ig) could be reconsidered.

A comprehensive analysis of DEL types: partial DEL individuals are prone to anti-D alloimmunization

BACKGROUND

The D antigen of the polymorphic Rh blood group system is of particular clinical importance regarding transfusion- and pregnancy-induced alloimmunization. Different RhD variants with specific clinical implications have been characterized. The least expressed D variants collectively called DEL are serologically detectable only by adsorption-elution techniques, with so far only poorly defined antigenic properties.

STUDY DESIGN AND METHODS

A comprehensive immunohematologic analysis of five of the six currently known DEL genotypes was performed. DEL phenotypes associated with the RHD(M295I), RHD(IVS3+1g>a), RHD(K409K), RHD(X418L), or RHD(IVS5-38del4) allele were characterized with extended serology and flow cytometry.

RESULTS

Epitope mapping with adsorption-elution revealed a prominent D epitope loss in the RHD(IVS3+1g>a)-associated DEL phenotype, whereas in the other four DEL types no signs of qualitative D antigen alteration were detected. The observation of alloanti-D in two RHD(IVS3+1g>a) cases confirmed the partial nature of this DEL phenotype. The RHD(M295I) phenotype exhibited the highest D antigen expression among all investigated DEL types, as determined by a semiquantitative adsorption-elution approach and flow cytometry.

CONCLUSION

In conclusion, evidence is provided that different DEL genotypes code either for partial or complete D antigen expression and that this finding is clinically relevant.

Secondary anti-D immunization by Del red blood cells

BACKGROUND

Recent molecular studies of the RHD gene have revealed that D(el) individuals retain a grossly intact RHD gene or have a portion of RHD in their genomes. No D(el) phenotype has yet been shown to induce a primary or secondary alloanti-D immunization, however.

CASE REPORT

A 67-year-old D- Japanese woman with a history of allosensitization from transfusion of D+ red blood cells (RBCs) was negative for anti-D at admission. After she received RBCs from 19 apparently D- donors, she developed anti-D with an 8-fold titer. The titer of anti-D increased further to 128-fold after transfusions of cross-match-compatible D- negative RBCs from 40 donors over the next 2 years. Two of 59 donors were found to be RHD gene-positive and antigen D- with a D(el) phenotype, that is, RHD(K409K).

CONCLUSION

This is the first case in which RBCs having the D(el) phenotype induced a secondary alloanti-D immunization. A D- donor with the RHD(K409K) allele was associated with the development of anti-D. Adverse episodes or evidence of hemolysis was not observed after the transfusion of RHD(K409K) RBCs. Further clinical evidence is needed to reveal whether the D(el) phenotype has a clinically relevant potential for anti-D immunization.

Novel weak D types 31 and 32: adsorption-elution-supported D antigen analysis and comparison to prevalent weak D types

BACKGROUND

Weak D types are thought to express rather quantitative than qualitative D antigen variants. Distinct type-specific phenotypes and weak D cases with anti-D alloimmunization, however, suggest a variable degree of D antigen alteration.

STUDY DESIGN AND METHODS

Variant D types were investigated by use of molecular typing, RHD sequencing, extended serologic D antigen investigations, and flow cytometric D antigen density determination.

RESULTS

Two novel weak D types were discovered, termed weak D type 31 and 32 with single RHD nucleotide substitutions coding for amino acid exchanges in predicted intracellular RhD polypeptide stretches, with antigen densities of approximately 130 and 50 D sites per red blood cell, respectively. Adsorption-elution technique-supported D epitope mapping of these two weak D types, the recently described weak D type 26, and of the most common Central European weak D types (weak D types 1, 2, 3, 4.0, and 4.1) demonstrated the expression of all tested D epitopes. In contrast, a distinct D epitope loss was detected in weak D type 15 and partial D control samples.

CONCLUSION

All novel and prevalent weak D types expressed all tested D epitopes. Our results indicate that adsorption-elution techniques may be of advantage whenever D epitope loss is suspected in extremely weak D variants.

Partial D, weak D types, and novel RHD alleles among 33,864 multiethnic patients: implications for anti-D alloimmunization and prevention

BACKGROUND

The D antigen includes category D, partial D, and weak D types, which are important because anti-D alloimmunization can occur in some but not all persons that express a variant RHD allele. At present, there is little prospective information on the prevalence of D variants among obstetric patients and potential transfusion recipients.

STUDY DESIGN AND METHODS

The RHD alleles were prospectively examined in a large patient population identified on the basis of a difference in anti-D reactivity between two reagents.

RESULTS

Fifty-five discrepancies (0.96% of D-) were noted among 33,864 ethnically diverse patients over 18 months, of which 54 represented mutated RHD alleles. Seven obstetric patients were assigned D- status based on serology; only 1 patient had a partial RHD allele. Ten of 25 (36%) obstetric patients and 4 of 6 (67%) female potential transfusion recipients of childbearing age or younger were assigned D+ status, and they expressed a D variant known to permit anti-D alloimmunization. In total 20 RHD alleles were identified including category, DVa or DVa-like alleles (n = 7), DAR (n = 8), and four novel RHD alleles including two new DAU alleles.

CONCLUSION

Given the complexity of D antigen expression, it is concluded that some clinically important D variants identified by standard serologic analysis phenotype as D+ and are potentially at risk for the development of anti-D.

Risk factors for alloimmunization by patients with sickle cell disease

Blood transfusion in patients with sickle cell disease (SCD) is limited by the development of alloantibodies to erythrocytes. In the present study, the frequency and risk factors for alloimmunization were determined. Transfusion records and medical charts of 828 SCD patients who had been transfused and followed at the Belo Horizonte Blood Center, Belo Horizonte, MG, Brazil, were retrospectively reviewed. Alloimmunization frequency was 9.9% (95% CI: 7.9 to 11.9%) and 125 alloantibodies were detected, 79% of which belonged to the Rhesus and Kell systems. Female patients developed alloimmunization more frequently (P = 0.03). The median age of the alloimmunized group was 23.3 years, compared to 14.6 years for the non-alloimmunized group (P < 0.0001). Multivariate analyses were applied to the data for 608 hemoglobin (Hb) SS or SC patients whose number of transfusions was recorded accurately. Number of transfusions (P = 0.00006), older age (P = 0.056) and Hb SC (P = 0.02) showed independent statistical associations with alloimmunization. Hb SC patients older than 14 years faced a 2.8-fold higher (95% CI: 1.3 to 6.0) risk of alloimmunization than Hb SS patients. Female Hb SC patients had the highest risk of developing alloantibodies. In patients younger than 14 years, only the number of transfusions was significant. We conclude that an increased risk of alloimmunization was associated with older patients with Hb SC, specially females, even after adjustments were made for the number of transfusions received, the most significant variable.

Three cases of massive fetomaternal hemorrhage presenting without clinical suspicion

Fetomaternal hemorrhage (FMH) is a common obstetrical occurrence most often associated with small volumes of blood transferred across the placenta. Fetomaternal hemorrhage leads to alloimmunization of Rh D-negative mothers, resulting in an increased risk of hemolytic disease of the newborn. Massive FMH involving volumes of blood greater than 30 mL can cause substantial fetal morbidity and mortality. Massive FMH may present with signs and symptoms such as decreased movement, sinusoidal heart rhythms, or fetal anomalies. We present 3 cases of clinically unexpected massive FMH of 206, 88, and 155 mL. The treating clinicians were unaware of any fetal or maternal signs or symptoms of FMH until contacted by the laboratory. These cases illustrate the necessity for FMH quantitation, even in the absence of clinical suspicion. Additional studies are needed to find better ways to identify these patients in advance. Development of criteria allowing identification of patients at risk would be of benefit to both mother and baby.

RBC alloimmunization and autoimmunization among transfusion-dependent Arab thalassemia patients

BACKGROUND

Thalassemia major is a common hemoglobinopathy in the Arabian Gulf region. However, limited data are available on the frequency of RBC alloimmunization and autoimmunization in transfusion-dependent Arab thalassemia patients.

STUDY DESIGN AND METHODS

A total of 190 thalassemia major patients were classified as Kuwaiti Arab and non-Kuwaiti Arab. Pretransfusion investigation records were reviewed for the presence of RBC alloantibody and autoantibody, and the age at which RBC alloantibody was developed.

RESULTS

Fifty-seven (30%) patients developed RBC alloantibodies. The most common clinically significant alloantibodies were directed against antigens in the Kell and Rh systems. Anti-K developed in 41 (72%) patients followed by anti-E in 26 (45.6%). RBC autoantibodies developed in 21 (11%) patients with and without underlying RBC alloantibodies. Sixty-six (49.6%) RBC alloantibodies developed between the ages of 2 and 10 years.

CONCLUSION

Several factors might have contributed to the high alloimmunization and autoimmunization rate observed in this study, including the heterogeneity of the population living in Kuwait, lack of better-matched donors for those patients, and the use of poststorage leukodepleted blood. It is recommended that thalassemia patients receive blood matched for Rh and Kell antigens and prestorage leukodepleted RBCs.

DNB: a partial D with anti-D frequent in Central Europe

To improve routine D typing and define transfusion strategy, it is important to establish the frequency of partial D alleles and their susceptibility to anti-D alloimmunization due to transfusion or pregnancy. We identified the partial D DNB that was caused by an RHD(G355S) allele associated with a CDe haplotype and whose phenotype presented a normal D in routine typing. The antigen density was about 6000 D antigens per red blood cell, and the Rhesus index was 0.02. Five anti-D immunization events with allo-anti-D titers up to 128 were observed. Twelve carriers of DNB were whites of Central Europe; the only Danish proband had Austrian ancestry. DNB was the most frequent partial D recognized so far in whites, occurring with frequencies of up to 1:292 in Switzerland. DNB was the underlying partial D phenotype in a relevant fraction of anti-D immunizations occurring in whites.

Evaluation of flow cytometric enumeration of foetal erythrocytes in maternal blood

In pregnant women subject to abdominal trauma or other foetomaternal haemorrhage, foetal red blood cells containing haemoglobin-F (HbF) can be found in the circulation. Recently, a monoclonal antibody to HbF has become commercially available, enabling application of a flow cytometric immunofluorescence method for accurately determining the concentration of HbF+ red blood cells. We demonstrate that white blood cells are included in the cluster selected as red blood cells and that these white blood cells exhibit a level of autofluorescence that coincides with the fluorescence signal from HbF+ red blood cells. However, these white blood cells can be excluded from the analysis, thus preventing spuriously increased HbF+ red blood cell counts. We present the results of patient samples containing HbF+ red cells as illustrations of the technique and as a potential interference by HbF-containing cells of nonfoetal origin. Using samples spiked with cord blood, the method is exactly linear with a high coefficient of correlation (r=0.997). Furthermore, the assay has excellent precision (CV < 2.4%), a low limit of detection (0.12% HbF+ RBC), is independent of Rhesus D and can be completed within 1.5 h. This method is suitable for accurate determination of foetomaternal haemorrhage.

Paediatric transfusion

Paediatric transfusion encompasses a wide range of clinical circumstances including the consideration of maternal antibodies, the changing nature of the transfusion recipient with respect to growth and development, and the management of inherited conditions which if optimally treated in early life may have problems which are delayed or less severe in adult life. Whilst the transfusion of adults and children has much in common, a child cannot be considered as a scaled down adult; there are many important differences. Developmental changes are most marked in the neonate and, together with the fact that their antibodies are maternally derived, this population provide some of the most striking challenges. The increased use of intra uterine transfusion adds an extra dimension here. A particular paediatric concern is the long-term consequences of transfusion. It is to be hoped that paediatric transfusion recipients will live long enough that any potential problems will manifest themselves, thus the aim must be to minimize transfusion risks.

Incidence of Rhesus isoimmunization in Rhesus-negative mothers in Ramadi, Iraq, in the mid-1990s

This work was carried out in Ramadi, Iraq over the period 1993 to 1997. Of 487 rhesus (Rh)-negative mothers tested and followed up, 172 were primigravida, 1.7% of whom were Rh-isoimmunized. The frequency of isoimmunization increased with increasing number of pregnancies (4.9% for second pregnancies to 45.4% for fifth pregnancies). Comparison of our results with other earlier studies shows that the incidence of Rh-isoimmunization in our study was considerably greater than the others.

Intravenous drug abuse is an indication for antepartum screening for RH alloimmunization. A case report and review of literature

Intravenous drug abuse is a risk for alloimmunization in pregnancy. One case is presented of a nulliparous Rhesus-negative parturient who shared her Rhesus-positive partner's needles for the injection of heroin; she subsequently developed elevated antepartum anti-D titers despite routine anti-D prophylaxis.

Severe hemolytic disease from rhesus anti-C antibodies in a surrogate pregnancy after oocyte donation. A case report

BACKGROUND

Maternal sensitization with rhesus anti-C antibodies is comparatively rare and usually benign. In pregnancies conceived using donor oocytes, the mother's blood group may differ from that of both the father and the oocyte donor, making blood group incompatibility more likely.

CASE

Twins, the result of a surrogate pregnancy using donor oocytes, were born with severe hemolytic disease due to rhesus anti-C antibodies. Both infants required exchange transfusion for profound anemia at birth. Isoimmunization in the surrogate mother was not detected antenatally. The twins were delivered by emergency cesarean section due to fetal compromise, detected fortuitously when the mother attended for routine fetal assessment at 35 weeks' gestation.

CONCLUSION

Isoimmunization with anti-C antibodies is not always benign and may cause significant hemolytic disease. With the success of in vitro fertilization and oocyte donation, more infertile couples may use these methods to conceive, with or without surrogacy arrangements. In such cases, the provision of antenatal care may become a complex matter, involving several parties, and good communication between everyone involved is vital. In pregnancies conceived with donor oocytes, there may be a higher risk of blood group incompatibility, and special vigilance is warranted.

An audit of anti-D sensitisation in Yorkshire

OBJECTIVE

To determine the likely factors that contribute to RhD sensitisation.

DESIGN

Retrospective study of all new cases of RhD sensitisation occurring between 1988 and 1991.

SETTING

Leeds Blood Centre, National Blood Service, Yorkshire.

POPULATION

One hundred and forty-seven cases of RhD sensitisation from 15 obstetric units within the Yorkshire region, of which 129 (312 pregnancies) could be assessed.

MAIN OUTCOME MEASURE

S Identification of potential immunising events and adherence with recommendations on anti-D immunoglobulin administration.

RESULTS

Twenty-eight women (22%) had immune anti-D antibodies during their first pregnancy or at delivery and 50 (39%) in their second pregnancy. Overall, 98 potential immunising events were identified in 62 women, excluding delivery; 67 women (52%) had no events, other than delivery. Miscarriages and medical terminations of pregnancy accounted for 81% of all identified events. Iatrogenic failure to adhere to recommendations for the administration of anti-D immunoglobulin occurred in a significant proportion of women who subsequently developed immune anti-D antibodies. Anti-D immunoglobulin failed to protect against immunisation despite adherence to the protocol in 20 events (20%), 13 of which involved miscarriages or termination of pregnancy < 20 weeks of gestation. Potentially, antenatal prophylaxis might have prevented 86% of immunisations that were identified during the first pregnancy.

CONCLUSIONS

The introduction of antenatal administration of anti-D immunoglobulin could significantly reduce the level of sensitisation in primigravidae, and adherence to recommendations for administration of anti-D immunoglobulin could be improved. Consideration should be given to reviewing the current recommendation that a dose of 250 IU of anti-D immunoglobulin is adequate following termination of pregnancy before a gestational age of 20 weeks.

[The combined efferent therapy of a blood-transfusion conflict in a puerpera]

Plasmapheresis, ultrafiltration of blood, and hemodialysis were effectively used in the treatment of a 20-year-old woman after cesarean section who was transfused 300 ml of wrong group blood. The resultant hemotransfusion conflict was characterized by shock, disseminated intravascular coagulation, hemolysis, acute pulmonary edema and renal failure. Plasmapheresis helped abolish the hemolysis. Pulmonary edema was eliminated by ultrafiltration of 2 liters of blood. Six sessions of hemodialysis administered within 10 days arrested renal insufficiency. The treatment administered may be considered as the method of choice in such patients.

Midtrimester Rh sensitization associated with circulating anticardiolipin antibodies and elevated maternal serum alpha-fetoprotein. A case report

The incidence of antepartum Rh isoimmunization has been limited by third-trimester Rh immune globulin (RhIg) administration. Prophylactic failures are uncommon but can occur if sensitization takes place prior to the 28th week of gestation. We report a case of midtrimester Rh sensitization in an anticardiolipin antibody-positive primipara coincident with the discovery of an elevated maternal serum alpha-fetoprotein value, oligohydramnios and fetal growth retardation. This case suggests that fetal-maternal hemorrhage and subsequent sensitization may be facilitated by anticardiolipin antibody-induced placental damage. Prophylactic midtrimester RhIg administration might avoid sensitization in similar cases.

Causes and clinical consequences of Rhesus (D) haemolytic disease of the newborn: a study of a Scottish population, 1985-1990

OBJECTIVE

To identify the reasons behind failures to prevent the development of Rhesus (D) haemolytic disease of the newborn.

DESIGN

Retrospective analysis of the case records of all pregnancies that resulted in the birth of an infant with a positive direct antiglobulin test on the cord red cells born to Rh(D) negative women between 1 April 1985 and 31 March 1990.

SETTING

Obstetric units in the South East Scotland region and the South East Scotland Regional Blood Transfusion Service Antenatal Laboratory.

MAIN OUTCOME MEASURES

The causes and clinical consequences of maternal immunisation to the Rhesus (D) antigen.

RESULTS

Between 1985 and 1990, 80 pregnancies resulted in the birth of an infant sensitised with anti-D on the cord red cells. There were no deaths due to haemolytic disease, but considerable resources were deployed in obstetric and neonatal care for these pregnancies. Sufficient data were available to categorise the cause of maternal immunisation in 70 pregnancies. Seven cases were due to immunisation by pregnancy before 1970. Sixty-three cases could be attributed to failure of the Rhesus programme: 10 cases (16%) were due to failure to implement the programme adequately, the other 53 cases (84%) were due to failure of the current guidelines to provide adequate protection. Late immunisation in an uncomplicated pregnancy was the single commonest identifiable cause.

CONCLUSIONS

It is likely that substantial further reductions in Rhesus (D) immunisation and haemolytic disease of the newborn will require changes in the Rhesus prevention programme. In particular the role of antenatal prophylaxis requires detailed consideration.

[Partial deletion of the D antigen in a family group. Determination of its antigenic density by flow cytometry]

Mutations within the genetic Rh system can produce partial deletions of one or more epitope of the D antigen, known as incomplete D. These people, classified Rh positive, are capable of producing anti-D antibodies when exposed to D positive red blood cells (rbcs). We describe the study of a Rh positive, 34 year old, spanish-indian ("mestiza") female patient, in whose blood anti-D antibodies were detected after a blood transfusions. The results of the tests showed a partial deletion of the D antigen in the patient and three of her family members.

PATIENTS AND METHODS

The following tests were done to the patient and her family members: 1) ABO and Rh typing; 2) Direct antiglobulin test; 3) Detection of irregular antibodies in their blood serum; 4) Rh genotype; 5) Cross matching of the patient's serum with rbcs of her Rh positive relatives; 6) Titration of a monoclonal anti-D (IgM) and a polyclonal anti-D (IgG) of human origin with the patient's rbcs and with Rh positive rbcs of her family members whose erythrocytes didn't react with the patient's serum; 7) Measurement of the antigenic density of the D antigen by flow cytometry (indirect immunofluorescence) in the rbcs of the patient and in those family members who had the defect, using a polyclonal anti-D (IgG).

RESULTS

1) An anti-D antibody which didn't react with its own Rh positive rbcs was found in the patient's serum; 2) This antibody didn't react with the Rh positive rbcs of her father and two out of her 4 brothers; 3) The cytometric study of these cells (R)r) showed a immunofluorescence pattern weaker than the control cells of the same genotype, but with a variable expression between 15 to 41%.

CONCLUSIONS

The study showed: 1) The presence of an anti-D antibody in a Rh positive patient who had been previously sensitized (by blood transfusion); 2) This antibody was able to react with Rh positive rbcs but not with those of the patient and her family members who had the same partial deletion; 3) The defect was transmitted heterozygously, with a high degree of penetration, but with variable expression; 4) A low antigenic density for her D antigen by flow cytometry.

Fetal-maternal bleed in the second trimester of pregnancy. A report of two cases

Two cases of nontraumatic fetal-maternal bleeding occurred in the second trimester. Both presented with mild, lower quadrant tenderness similar to round ligament pain, illustrating the potential for a misdiagnosis.

Intravenous anti-D gammaglobulin for the prevention of rhesus isoimmunization caused by platelet transfusions in patients with malignant diseases

Previous studies of sensitization to RhD by RhD-positive platelet transfusions in RhD-negative cancer patients have shown different frequencies of alloimmunization (max. 19%). We studied 37 RhD-negative patients who received RhD-incompatible platelet transfusions and simultaneously anti-D-immune globulin. We provide evidence that in this setting RhD-prophylaxis is highly effective in preventing alloimmunization due to RhD antigen, since none of the patients studied developed anti-D. Detection of other red blood cell antibodies than anti-D proves the possibility of immunization in these patients. Prevention of isoimmunization in patients with malignant diseases is recommended especially in young females, since an increasing number of patients are having successful pregnancies, despite prior or even during cytotoxic therapy.

Underutilization of Rh prophylaxis in the emergency department: a retrospective survey

STUDY OBJECTIVE

To determine the practice of emergency physicians with regard to the issue of Rh isoimmunization.

DESIGN

A retrospective chart review.

SETTING

A university-affiliated tertiary care hospital emergency department.

TYPE OF PARTICIPANTS

Pregnant women presenting with a risk factor for Rh sensitization.

MEASUREMENTS AND MAIN RESULTS

One hundred thirty-eight patient encounters were analyzed descriptively as to whether they were candidates for Rh immune prophylaxis, and if so, whether it was given. Most (68%) were hospitalized. Of those, all were Rh typed, but two patients were not given Rh immune globulin (RhIG) when indicated. Of those discharged from the ED, most (86%) were not Rh typed, and none was administered RhIG.

CONCLUSION

This study demonstrates a need for increased attention to the potential for Rh isoimmunization in patients presenting to the ED.

Studies on the prenatal chromosomal analysis and the changes of maternal serum alpha-fetoprotein following chorionic villus sampling

Transcervical chorionic villus sampling (CVS) was performed in 174 patients between 7 & 12 menstrual weeks of pregnancy opting for prenatal diagnosis. Advanced maternal age was the most common indication for CVS (39.7%). The sampling success rate was 95.4% (166/174), representing 88.9% at 7 to 8 weeks, 98.9% at 9 to 10 weeks & 92.7% at 11 to 12 weeks gestation. In 139 of 174 patients (80%), successful sampling was accomplished in one or two catheter passages only. Four spontaneous fetal losses (2.3%) occurred. The cytogenetic analysis routinely used was the direct overnight & long-term culture methods which revealed 4 abnormalities (2.4%). To date, 90 of the women have been delivered & all infants are doing well and the remaining 65 pregnancies are continuing uneventually. Maternal serum alphafetoprotein (MSAFP) concentration was determined in 72 patients immediately before & after CVS. A significant increase of 20% or more, comparable to pre CVS levels, was noted immediately after sampling in 56 of 72 patients (77.8%). The increase in MSAFP concentration correlated with the amount of villi sampled (r = 0.498, p less than 0.001) & with the number of sampling attempts (p less than 0.05). Estimated CVS related fetomaternal hemorrhage (FMH) ranged from 0.005 to 0.1552 ml and in 5 of 72 patients (6.90%) 0.06 ml or more of FMH was noted. Two of the 5 patients had FMH of 0.1 ml or more.

Intravenous drug abuse causes Rh immunization

Intravenous drug abuse causes many health problems. From March 1989 to January 1990 of 27 Rh-negative women (28 pregnancies) referred to our centre, 4 women (5 pregnancies) were Rh immunized due to the sharing of needles and blood with their Rh-positive partners. Severe hydrops was present in 4 of their 5 fetuses when they were first seen at 17-35 weeks of gestation. Only the fetus first seen at 35 weeks survived. That infant was moribund at birth and now has evidence of leukomalacia and porencephaly. The fifth fetus, not hydropic, required two intravascular fetal transfusions in order to survive. A fifth woman, immunized in a similar manner, had a spontaneous abortion. These fetuses represent some of the earliest and severest examples of hydrops fetalis ever seen at our centre. The severity of their fetal hemolytic disease is probably due to the fact that their mothers' exposure to Rh(D) antigen by blood sharing was continuous and ongoing. Because of their aberrant behaviour, these women have suffered irreversible reproductive damage.

Detecting fetomaternal hemorrhage: a comparison of five methods

Appropriate postpartum administration of Rh immune globulin relies on sensitive detection and accurate quantitation of fetomaternal hemorrhage (FMH). Recently, the microscopic Du test (micro Du) enhanced with polyethylene glycol (PEG Du) and flow cytometry (FC) have been advocated for this purpose. Three qualitative methods (micro Du, rosette test, and PEG Du) and two quantitative methods (acid elution and FC) for assessing FMH were evaluated with particular attention given to PEG Du and FC. In vitro studies comprised 10 series of dilutions of D+ cord cells in D- adult cells to yield D+ cell concentrations of 0.06, 0.12, 0.25, 0.50, 0.75, 1.0, and 2.0 percent. Additionally, 26 postpartum samples were tested. Of the qualitative techniques, the micro Du test was the least sensitive with 20 percent false-negative results occurring at 0.5 percent fetal cells. The PEG Du test was only slightly more sensitive and offered no clinical advantage. The rosette test was the most sensitive, consistently detecting fetal cells at concentrations of 0.25 percent or greater. FC and acid elution showed similar results, with good correlation obtained between measured and expected quantities of fetal cells (r = 0.99 and 0.96, respectively). One of 26 postpartum samples was positive by all screening techniques; acid elution and FC detected 0.3-percent concentrations of fetal cells and 0.17-percent concentrations of D+ cells, respectively. Although acid elution is a more commonly used method for quantitating FMH, FC offers an acceptable alternative that is capable of analyzing large numbers of cells with objectivity and reproducibility.

[Studies on manifestations of Rh-related hemolytic disease of the newborn in the years 1974-1989 in the Erfurt district]

In the course of 13 years (1977-1989) 223 of 223,121 liveborn infants in the district of Erfurt suffered from haemolytic disease due to Rh-isoimmunization, 0.1 per cent died. An initial drop of morbidity from 1.6 to 0.6 of 1000 newborns was followed by stagnation and further increase during the last years. More than 50% of the affected babies were delivered by women who had to be protected from sensibilization by immune prophylaxis. The cause for the immunization were deliveries (75%), miscarriages and interruptions (23%). The most important reason for the insufficient decrease of the Rh-morbidity is the failure of immune prophylaxis in the case of ABO-incongruence between mother and child. Our results support the demands for a general immune prophylaxis without taking into consideration the main blood groups and the number and result of the pregnancy. The quantity of severe erythroblastosis (7 stillborn and 5 hydropic liveborn) demonstrates the necessity to improve the prenatal management of these babies.

Rh immunization by the partial D antigen of category DVa

Reported here is the first example of a partial D antigen stimulating the production of anti-D: stimulation was of fetal origin. During her second pregnancy, anti-D developed in the serum of a D-negative mother who had received Rh immunoglobulin after the birth of her first D-positive child. Her second baby had moderate neonatal jaundice and was successfully treated by phototherapy. Subsequently the red cells of the father and of the first child were shown to carry a partial D antigen of category DVa type. Six available batches of Rh immunoglobulin reacted with DVa cells.

[Immunization against blood group antigens by allogeneic bone transplantation]

33 bone allotransplants (cryopreserved) of AB0- and Rh-incompatible (donor-recipient) patients were performed to evaluate the question which AB0 Rh-incompatibility leads to immunization of the bone transplant recipient. Several different antibodies were tested pre- and postoperatively in the recipient. Regarding the Rh-system no immunization was demonstrable; however, a significant increase of antibody leads was found regarding the AB0-system. Thus, in bone bank techniques AB0 compatibility is important for allogeneic bone transplantation in young women. Otherwise, there is a risk for the development of MHN in case of pregnancy. Blood group-typing is not necessary in other patient groups. Although no Rh-antibodies were demonstrable, a similar mechanism can be postulated for the Rh-system. We, thus, conclude that in allogeneic bone tx in young women the Rh-system has to be taken into consideration.