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PubMed2005

[Foetomaternal erythrocyte incompatibilities: from immunohaematologic surveillance of pregnant women to haemolytic disease of the newborn].

Despite the generalization of prevention measures against foetomaternal alloimmunization with anti-D immunoprophylaxis since 1970s, retrospectively 30 years later, its complications (new-born child's severe haemolytic disease, foetal death by anemia or nuclear icterus by bilirubin encephalopathy) have not disappeared. At the same time, alloimmunizations against antigens other than D increase with no possible prevention. As part of the set up in France of regional files analysing and making an inventory of serious foetomaternal incompatibilities requiring in utero or neonatal transfusion, we felt the need to synthesize current data, biological profiles (early screening of erythrocytic alloimmunization and its follow up during pregnancy, father's immunohaematologic status, evaluation of in utero immune haemolysis and impact of new non invasive techniques of diagnosis-RH1 foetal genotypage from ADN foetal of RH1--mothers' maternal plasma), clinical and paraclinical data (evaluation of foetal haemolysis by echography, recording of foetal movements and foetal cardiac rhythm), therapeutic indicators (in utero foetal transfusions or exsanguinotransfusions, neo and postnatal transfusions or exsanguinotransfusions, induced premature labour, newborn's intensive continue phototherapy and Rhesus immunoprophylaxis) in order to enable medical and paramedical professionals to carry out the specific supervision of pregnancies with foetomaternal incompatibility, the in utero, neo- and postnatal treatment of child and the efficient therapeutic prevention of anti-D alloimmunization, in a cooperative way.

Adult↗
PubMed2005

[Transfusions of rhesus-incompatible platelet concentrates in Rouen University Hospital: procedures and consequences].

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.

Adolescent↗
PubMed2006

Recent developments in fetal nucleic acids in maternal plasma: implications to noninvasive prenatal fetal blood group genotyping.

The discovery of circulating cell-free fetal DNA in maternal plasma has opened up new possibilities for noninvasive prenatal diagnosis. Fetal DNA in maternal plasma has been used for the noninvasive prenatal determination of the RhD status of fetuses carried by RhD-negative pregnant women. In such analysis, the possible need of an internal control for the presence of detectable amounts of fetal DNA in a particular maternal plasma sample has been actively discussed. Recently, the development of a robust method for discriminating single nucleotide differences in plasma DNA using single allele base extension reaction (SABER) followed by matrix-assisted laser-desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) has opened up the possibilities of using a panel of single nucleotide polymorphisms as such a positive control. A second approach is the recent successful development of fetal epigenetic markers which can be developed into universal fetal DNA markers. These developments hold promise to allow the eventual widespread utilization of maternal plasma DNA analysis for the noninvasive prenatal diagnosis of blood group mismatches between the mother and fetus.

Blood Group Antigens↗
PubMed2006

Molecular genetics of RH and its clinical application.

BACKGROUND: The RH genes RHD and RHCE encode two proteins that represent the clinically most important blood group system defined by the sequences of red cell membrane proteins. In the last five years the field has been moving from defining the underlying molecular genetics to applying the molecular genetics in clinical practice. MATERIALS AND METHODS: The state of the current knowledge is briefly summarized using recent reviews and original work since 2000. RESULTS: The RHD and RHCE genes are strongly homologous and located closely adjacent at the human chromosomal position 1p36.11. Part of the genetic complexity is explained by the clustered orientation of both genes with their tail ends facing each other. The SMP1 gene is located interspersed between both RH genes. Using additional genetic features of the RH gene locus, RHCE was shown to represent the ancestral RH position, while RHD is the duplicated gene. More than 150 alleles have been defined for RHD alone. They were classified based on antigenic and clinical properties into phenotypes like partial D, weak D and DEL. Among the D negative phenotype a large variety of non-functional alleles were found. The frequencies of these distinct alleles vary widely among human populations, which has consequences for clinical practice. CONCLUSION: Rhesus is a model system for the correlation of genotype and phenotype, facilitating the understanding of underlying genetic mechanisms in clustered genes. With regard to clinical practice, the genetic diagnostics of blood group antigens will advance the cost-effective development of transfusion medicine.

Alleles↗
PubMed2006

Alloimmunity to RhD in humans.

The RhD protein is expressed only on human red blood cells (RBC), and is one of the most immunogenic of the blood groups. It is of clinical importance since the alloantibody (anti-D) can hemolyse D positive RBC after blood transfusion, or cause hemolytic disease of the newborn. The immunogenicity of D is better understood with the knowledge of the genetic basis of the protein(s) involved, the molecular orientation in the RBC membrane, and the nature of the cellular immune response to proteins. The adaptive humoral response consists of antigen presenting cells, T-cells and B-cells, which interact cooperatively to result in antibody against the antigen in question. The anti-D that B-cells produce is targeted against surface membrane determinants (B-cell epitopes) and are conformational i.e. non-contiguous amino acids. The antigen specific T-cells recognize short linear peptides in the context of MHC class II, and these T-cell epitopes can reside anywhere in the protein. Since the RhD protein in D-positive individuals differs by some 35 amino acids from the RhCcEe protein in D-negative individuals, the opportunity for generating immunogenic T-cell epitopes is much greater than that for alleles characterized by a single amino acid difference e.g. E and e. Multiple conformational B-cell epitopes are also created by the presence of several D-specific amino acids in extracellular loops on the red cells surface, which may stimulate several B-cell clones and develop a strong polyclonal antibody response. With greater understanding comes the possibility of manipulating the immune response to D in clinical situations.

Animals↗
PubMed2005

Specificity and isotype of Rh specific antibodies produced by human B-cell lines established from alloimmunized Rh negative women.

Despite the successful outcome of anti-D prophylaxis program, alloimmunization still occurs. The aim of this study was to examine the specificity and isotype of anti-Rh antibodies in plasma samples of Rh negative alloimmunized individuals and to study the same parameters in lymphoblastoid cell lines (LCLs) generated from the same donors. Specificity of anti-Rh antibodies was determined in plasma of nine alloimmunized subjects by direct hemagglutination using a panel of known RBC genotypes and isotype of specific antibodies were identified by an antigen specific ELISA. Similar methods were employed to determine specificity and isotype of antibodies produced by Rh specific LCLs established from four donors. LCLs were generated by Epstein-Barr virus transformation of peripheral blood mononuclear cells isolated from each donor followed by their culture over a feeder of human fetal fibroblasts. Upon emergence of lymphoblastoid cells, culture supernatants were assayed for presence of Rh specific antibody by hemagglutination assay. Anti-D was the predominant antibody in both plasma samples and among the 128 established LCLs; however, antibodies to other Rh specificities namely C and E were also produced. The isotype of anti-Rh antibody in all plasma samples was found to be IgG, predominantly IgG1, combined in 7 samples with IgM. Similarly 76%, 9.2% and 14.8% of LCLs were determined to produce antibody of IgG, IgM and of both isotypes, respectively. The data supported that the D antigen is the immunodominant component of the Rh system as indicated by the in vitro and in vivo profiles of Rh specificities in our alloimmunized subjects.

Adult↗
PubMed2006

A case of severe Rh (D) alloimmunization treated by intensive plasma exchange and high-dose intravenous immunoglobulin.

BACKGROUND: In extremely severe Rh (D) alloimmunization, during pregnancy, early diagnosis and treatment is essential to avoid hydrops fetalis. Intrauterine transfusion (IUT) is of utmost importance in the prevention of fetal anemia but it is usually feasible only after 20 weeks of pregnancy. Therefore, additional treatment options in early pregnancy are needed. STUDY DESIGN AND METHODS: A 27-year-old severely D+C immunized woman was admitted at 8 weeks of gestation in her fifth pregnancy with an extremely high concentration of anti-D. Her first pregnancy was uneventful but resulted in D+C alloimmunization. The next two pregnancies were unsuccessful, because of hydrops fetalis resulting in fetal death in pregnancy week 20 and 24, respectively, despite treatment with high-dose intravenous immunoglobulin (IVIG) and IUT treatment. A fourth pregnancy was terminated with legal abortion. The patient was eager and persistent to accomplish a successful pregnancy. Therefore, a combination of treatments consisting of plasma exchange (PE) three times/week and IVIG 100g/week was started in pregnancy week 12. PE was performed 53 times and totally 159L of plasma was exchanged. RESULTS: The anti-D concentration was 12mug/mL (IAT titer 2000) before start of treatment by PE and IVIG in pregnancy week 12. The concentration of anti-D was gradually reduced to approximately 3mug/mL after only two weeks of treatment and was maintained at that level until pregnancy week 22. In pregnancy week 26 and 27, signs of hydrops were detected by ultrasonography and IUT were performed at each occasion. Sectio was inevitable at pregnancy week 28+1 and a male baby was born: Hb 58g/L (cord sample) and 68g/L (venous sample); weight 1385g; Apgar score=4-5-7; Bilirubin 56-150mmol/L (4h). Exchange transfusion was performed on day two and day five. Phototherapy was also implemented for eight days. The newborn's recovery thereafter was uneventful and complete. CONCLUSION: A combination of PE and IVIG may be an efficient treatment possible to start in early pregnancy in patients with extremely severe Rh (D) alloimmunization, with a history of hydrops fetalis in previous pregnancies.

Cesarean Section↗
PubMed1994

Clinical utility of fetal RhD typing in alloimmunized pregnancies by means of polymerase chain reaction on amniocytes or chorionic villi.

OBJECTIVE: Our purpose was to describe the clinical utility of a deoxyribonucleic acid amplification method for determining fetal RhD status in alloimmunized pregnancies STUDY DESIGN: Six RhD-negative women with alloimmunized pregnancies and heterozygous partners underwent amniocentesis (n = 5) or chorionic villus sampling (n = 1). Fetal RhD type was determined by polymerase chain reaction and results disclosed to the attending physicians. RESULTS: Knowledge of the fetal RhD status avoided further invasive procedures in two pregnancies and facilitated the timing or performance of intrauterine transfusions in the remainder. CONCLUSIONS: In alloimmunized pregnancies the ability to RhD-type the fetus in amniotic fluid avoids the risks of fetomaternal hemorrhage and increased sensitization associated with fetal blood sampling or chorionic biopsy. This allows more rational pregnancy management, avoiding invasive procedures in the presence of an RhD-negative fetus, or planning therapeutic interventions or offering termination of pregnancy in the presence of an RhD-positive fetus.

Amniotic Fluid↗
PubMed1997

Polymerase chain reaction determination of RhC, Rhc, and RhE blood types: an evaluation of accuracy and clinical utility.

OBJECTIVE: Polymerase chain reaction amplification of a portion of the RhC/c/E/e gene could lead to a rapid, accurate determination of fetal RhC/c/E status. The purpose of this study was to evaluate the accuracy of this technique by testing for the first time a large number of deoxyribonucleic acid samples derived from individuals whose RhC/c/E status was established by standard serologic methods. We also evaluated the potential clinical utility of polymerase chain reaction to ascertain fetal antigen status. STUDY DESIGN: Samples were obtained from Centre d'Etude du Polymorphisme Humain families used for studies of genetic variation (n = 655). Deoxyribonucleic acid was extracted by standard techniques. With few modifications, published primers and reaction conditions were used. Samples were digested with restriction enzymes yielding characteristic electrophoresis patterns for RhC/c/E. Clinical utility was assessed by review of all patients evaluated for erythrocyte sensitization. RESULTS: RhC-positive (n = 479), RhC-negative (n = 176), Rhc-positive (n = 524), Rhc-negative (n = 131), RhE-positive (n = 131) and RhE-negative (n = 524) samples were evaluated. The sensitivity of RhC/ c and E typing by polymerase chain reaction was 98.3%, 98.1%, and 96.9%, respectively. The specificity of polymerase chain reaction for identifying the RhC/c/E antigens was 91.5%, 94.7%, and 99.2%, respectively. CONCLUSIONS: Although it would appear that use of polymerase chain reaction to establish RhC/c/E type could aid in evaluation of RhC/c/E sensitization, we are concerned about the instances of antigen-positive individuals characterized as antigen negative. Further study is necessary to determine if this reflects a polymorphism, mutation, a data coding error, or a combination. The Centre d'Etude du Polymorphisme Humain database is known to contain such errors at a rate that may surpass the error rate of our testing. A second molecular technique could be used to achieve better accuracy in the ascertainment of Rh C/c/E type. On the basis of a review of our patient population, molecular deoxyribonucleic acid techniques now available could aid the management of erythrocyte sensitization in pregnancy in > 96% of cases.

Blood Grouping and Crossmatching↗
PubMed2002

Management of rhesus alloimmunization in pregnancy.

Hemolytic disease of the newborn secondary to rhesus alloimmunization was once a major contributor to perinatal morbidity and mortality. Today, rhesus immune globulin has markedly decreased the prevalence of this disease so that only one to six cases occur in every 1000 live births. The rarity of this condition warrants consideration of consultation or referral to a maternal-fetal medicine specialist. Once sensitization occurs, rhesus immune globulin is no longer effective. Evaluation for the presence of maternal anti-D antibody should be undertaken at the first prenatal visit. First-time sensitized pregnancies are followed with serial maternal titers and, when necessary, serial amniocenteses to detect fetal bilirubin by DeltaOD(450). In cases of a heterozygous paternal genotype, new deoxyribonucleic acid techniques now make it possible to diagnose the fetal blood type through amniocentesis or even from plasma/serum deoxyribonucleic acid analysis. When there is a history of an affected fetus or infant, maternal titers are no longer diagnostic as a screening test. Serial peak middle cerebral artery velocities using Doppler ultrasound can be used in these pregnancies to detect fetal anemia. In some situations, intrauterine transfusion is necessary through ultrasound-directed puncture of the umbilical cord with the direct intravascular injection of red cells. Perinatal survival rates of more than 90% have been reported; hydrops fetalis reduces the chance for a viable outcome by up to 25%. Immediate neonatal outcome is complicated by the need for repeated transfusions secondary to suppressed erythropoiesis. Long-term studies have revealed normal neurologic outcomes in more than 90% of cases. Future therapy will involve selective modulation of the maternal immune system making the need for intrauterine transfusions a rarity.

Amniocentesis↗
PubMed1996

Fetal RhD typing by polymerase chain reaction in pregnancies complicated by rhesus alloimmunization.

OBJECTIVE: To review the specificity and sensitivity of diagnostic techniques using the polymerase chain reaction (PCR) on amniotic fluid (AF) samples for the determination of fetal RhD status. DATA SOURCES: A MEDLINE computerized search was conducted for January 1991 through March 1996 using the key terms "polymerase chain reaction," "rhesus," and "RhD typing." METHODS OF STUDY SELECTION: All articles describing the use of PCR in AF for RhD typing were reviewed. Only cases in which the results of PCR testing were confirmed by fetal or neonatal serology were included in the final analysis. TABULATION, INTEGRATION, AND RESULTS: The results of PCR typing were compared with serology to determine the sensitivity, specificity, and positive and negative predictive values of DNA-based techniques. A total of 500 cases were reviewed, in which four different sets of oligonucleotide primers were used. The sensitivity and specificity of PCR typing were 98.7% and 100%, respectively, and the positive and negative predictive values were 100% and 96.9%, respectively. In five cases, an RhD-positive fetus was incorrectly diagnosed: Two fetuses died, one neonate needed exchange transfusions, and another neonate needed phototherapy in conjunction with a simple transfusion. The remaining infant was lost to follow-up. A theoretical model indicated that amniocentesis with PCR-based techniques for fetal RhD typing would be associated with a fourfold reduction in perinatal loss compared with funipuncture and serology for fetal typing. CONCLUSIONS: This lower rate of procedure-related loss makes RhD typing using AF the preferred method for assessing the fetal Rh status in cases of a heterozygous paternal genotype.

Algorithms↗
PubMed1998

Prenatal diagnosis of the fetal Rhc genotype from peripheral maternal blood.

OBJECTIVE: To determine the fetal Rhc genotype by using the polymerase chain reaction (PCR) amplification procedure and maternal blood at the different steps of the fetal cell enrichment process. METHODS: Maternal peripheral venous blood samples were obtained from 11 pregnant women homozygous for the C antigen before amniocentesis. Three were not alloimmunized and eight were alloimmunized. The fathers were known to be heterozygous or homozygous for the c antigen by serologic testing. The mononuclear cell layer was isolated from maternal blood and flow sorted using monoclonal antibodies to CD36 or CD71 and glycophorin A. This was followed by PCR of the blood, mononuclear cells, and the sorted cells with allele-specific primers to RhCc genes. Gel electrophoresis was performed to predict fetal Rhc genotype. The fetal RhCc genotype was confirmed by serologic and DNA testing. RESULTS: All infants were positive for the Rhc gene. The positive fetal Rhc genotype was determined correctly in three of the 11 maternal blood samples without enrichment, in six of the nine mononuclear cell samples, and in seven of the eight sorted cell samples. The fetal genotype from one sorted sample was predicted to be homozygous C. One infant was determined by serology on cord blood to be negative for the c antigen, but repeated infant DNA amplification was consistent with the c genotype. CONCLUSION: Noninvasive fetal Rhc genotyping can be determined by PCR amplification of the rare fetal cells in maternal blood. These data reaffirm that enrichment of maternal blood for fetal cells is necessary to improve the sensitivity of the test.

Blood Grouping and Crossmatching↗
PubMed1985

Expression of Rh0(D) antigen in choriocarcinoma of the uterus in an Rh0(D)-negative patient: report of a case.

Choriocarcinoma of the uterus developed in an Rh0(D)-negative woman six weeks after delivery of a normal Rh0(D)-positive child. Although the patient's medical history did not show any previous sensitization, a strong anti-Rh0(D) antibody was detected during evaluation preceding surgical removal of the tumor. The tumor was considered the most probable cause of the Rh0(D) sensitization, since large Rh0(D)-positive areas of tumor were demonstrated by the immunoperoxidase method. This finding indicates that the Rh0(D) antigen is not restricted to erythrocytes, as commonly assumed, but can also be expressed on other tissue, such as tumor tissue.

Adult↗