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M A Overbeeke

Publications and source records attributed to M A Overbeeke.

At least 37 records · Page 2Linked to original sources
PubMed1996

Involvement of Ser103 of the Rh polypeptides in G epitope formation.

BACKGROUND: Almost all red cells that carry D and/or C antigens also express the G antigen (Rh12). A study was conducted on the molecular background of the G epitope. STUDY DESIGN AND METHODS: Two unrelated donors with the rare ccDEe, G- phenotype and one donor with the ccEe, G+ phenotype were studied. Genomic DNA and cDNA of these donors were studied with polymerase chain reaction, Southern blot, and sequence analysis, with special focus on exon 2, because it is only in this exon that there are supposed to be similarities between RHD and the RHC allele, but not between RHD and the RHc allele. RESULTS: In both ccDEe, G- donors, a nucleotide substitution was found in exon 2 of RHD; T307 was replaced by C307, which predicted a Ser->Pro substitution at amino acid position 103 of the D polypeptide. The ccEe, G+ donor carried the complete exon 2 of RHD. Moreover, despite the absence of all known D epitopes, this donor also carried RHD characteristics in exons 1 to 3 and exon 9 and further downstream. CONCLUSION: Ser103, encoded by exon 2 of the RH genes, is involved in G epitope formation.

Blotting, Southern↗
PubMed1996

Characterization of the hybrid RHD gene leading to the partial D category IIIc phenotype.

BACKGROUND: A D-positive white woman was found to have produced alloanti-D leading to hemolytic disease of the newborn in her third D-positive child. The maternal D was identified as the partial D category IIIc antigen (DIIIc). The molecular basis of this phenotype was studied. STUDY DESIGN AND METHODS: The proposita and her relatives were phenotyped for Rh system antigens with standard reagents. D(IIIc) typing of D-positive red cells was done with serum that contained anti-D from the proposita. Southern blot analysis and RHD-specific polymerase chain reactions were performed with genomic DNA. Rh transcripts were cloned and sequenced. RESULTS: Six relatives of the proposita were found to express the DIIIc phenotype, which traveled with Ce. The DIIIc phenotype was inherited in a Mendelian fashion. Southern blot analysis showed an identical digestion pattern in D(IIIc) individuals and in DD controls. Three different Rh transcripts were found. Two Rh transcripts were derived from RHCE (RHce and RHCe). The RHD-derived Rh transcript was the same as that of the published RHD sequence, apart from exon 3, which appeared to be exon 3 of RHCE. At the genomic level, RHD exon 3 was missing in all individuals expressing D(IIIc). CONCLUSION: This study shows the characteristics of a new hybrid D-CE-D allele encoding D(IIIc). It may be concluded that exon 3 of RHD is not involved in the formation of any of the D epitopes known at present, but rather encodes a new D epitope or D epitopes, as yet undefined by monoclonal anti-D reagents.

Adult↗
PubMed1996

Characteristics of anti-Cob in vitro and in vivo: a case study.

Serologic and biologic properties of an example of anti-Cob were investigated. The antibody was of the IgG class, and it bound small amounts of complement. It reacted optimally in the albumin-antiglobulin test with little or no enhancement of its reactivity in tests using enzymes. Additional experiments indicated that the Cob antigen is resistant to treatment with chemicals known to destroy other antigens. The antibody caused shortened survival of radiolabeled Co(b+) donor red cells in our patient. At 24 hours, nearly 50 percent of the red cells were no longer detectable in the circulation. It is concluded that anti-Cob is a clinically relevant antibody, a fact that must be taken into account when transfusing patients with anti-Cob.

Journal Article↗
PubMed1995

Rapid Rh D genotyping by polymerase chain reaction-based amplification of DNA.

Rh (rhesus) D is the dominant antigen of the Rh blood group system. Recent advances in characterization of the nucleotide sequence of the cDNA(s) encoding the Rh D polypeptide allow the determination of the Rh D genotype at the DNA level. This can be of help in cases in which red blood cells are not available for phenotyping, eg, when in concerns a fetus. We have tested three independent DNA typing methods based on the polymerase chain reaction (PCR) for their suitability to determine the Rh D genotype. DNA derived from peripheral blood mononuclear cells from 234 Rh-phenotyped healthy donors (178 Rh D positive and 56 Rh D negative) was used in the PCR. The Rh D genotypes, as determined with a method based on the allele-specific amplification of the 3' noncoding region of the Rh D gene described by Bennett et al (N Engl J Med 329:607, 1993), were not concordant with the serologically established phenotypes in all cases. We have encountered 5 discrepant results, ie, 3 false-positive and 2 false-negative (a father and child). Rh D genotyping with the second method was performed by PCR amplification of exon 7 of the D gene with allele-specific primers. In all donors phenotyped as D positive tested so far (n = 178), the results of molecular genotyping with this method were concordant with the serologic results, whereas a false-positive result was obtained in one of the D-negative donors (also false-positive in the first method). Complete agreement was found between genotypes determined in the third method, based on a 600-bp deletion in intron 4 of the Rh D gene described by Arce et al (Blood 82:651, 1993), and serologically determined phenotypes. The Rh blood group system is complex, and unknown polymorphisms at the DNA level are expected to exist. Therefore, although genotypes determined by the method of Arce et al were in agreement with serotypes, it cannot yet be regarded as the golden standard. More experience with this or other methods is still needed.

Alleles↗
PubMed1995

Rh E/e genotyping by allele-specific primer amplification.

It has been shown that the Rhesus (Rh) blood group antigens are encoded by two homologous genes: the Rh D gene and the Rh CcEe gene. The Rh CcEe gene encodes different peptides: the Rh C, c, E, and e polypeptides. Only one nucleotide difference has been found between the alleles encoding the Rh E and the Rh e antigen polypeptides. It is a C-->G transition at nucleotide position 676, which leads to an amino acid substitution from proline to alanine in the Rh e-carrying polypeptide. Here we present an allele-specific primer amplification (ASPA) method to determine the Rh E and Rh e genotypes. In one polymerase chain reaction, the sense primer had a 3'-end nucleotide specific for the cytosine at position 676 of the Rh E allele. In another reaction, a sense primer was used with a 3'-end nucleotide specific for the guanine at position 676 of the Rh e allele and the Rh D gene, whereas the antisense primer had a 3'-end nucleotide specific for the adenine at position 787 of the Rh CcEe gene. We tested DNA samples from 158 normal donors (including non-Caucasian donors and donors with rare Rh phenotypes) in these assays. There was full concordance with the results of serologic Rh E/e phenotyping. Thus, we may conclude that the ASPA approach leads to a simple and reliable method to determine the Rh E/e genotype. This can be useful in Rh E/e genotyping of fetuses and/or in cases in which no red blood cells are available for serotyping. Moreover, our results confirm the proposed association between the cytosine/guanine polymorphism at position 676 and the Rh E/e phenotype.

Alleles↗
PubMed1995

Red cell antibodies in pregnancy: there is no 'critical titre'.

The purpose of this study was to determine the predictive value and reliability of using a 'critical titre' when assessing the ability of red cell alloantibodies to cause haemolytic disease of the newborn. Titration studies and clinical follow-up of 418 antenatal cases where the mothers had red cell antibodies were studied retrospectively. The antibody specificities were anti-D (n = 359), anti-c (n = 34), anti-E (n = 19) and anti-K (n = 6). Depending on the titre being lower or higher than 16 in the indirect antiglobulin test, the severity of disease was established on the given therapy. Anti-D antibodies with a titre 16 were present in 20% of all cases associated with transfusion need of the child; for anti-c, -E and -K the figure was 4%. Titres > or = 16 resulted in both groups in 50% of the cases in phototherapy only, or no therapy at all. Titres are therefore not reliable indicators for predicting the severity of haemolytic disease of the newborn. Neither should they be used as a guide to whether or not antenatal intervention is indicated. Alternative quantitative or functional assays that measure cytotoxic lysis or phagocytosis or a combination of both should be performed instead.

Blood Group Antigens↗
PubMed1994

Autoimmune haemolytic anaemia during pregnancy.

We describe a 31-year-old woman, who presented during her first pregnancy, with severe haemolytic anaemia due to auto-immune antibodies against erythrocytes. IgG warm-antibodies, as well as IgM antibodies were found in her serum. This idiopathic form of auto-immune haemolysis was successfully treated with glucocorticoids. During her second pregnancy auto-immune haemolysis again developed and was treated similarly. Two healthy children were born. The uneventful outcome we saw with our patient is in keeping with other reports in the literature.

Adult↗
PubMed1994

Serological characteristics of partial D antigen category VI in 8 unrelated blood donors.

Classification of subjects with a partial D antigen is traditionally performed with immune anti-D sera. The development of monoclonal antibodies enables a fine analysis to be made of the specificity of the epitopes that are present or missing in these cases. A systematic search in a Caucasian donor population of 17,500 revealed 8 unrelated male individuals (frequency 0.05%) with a red cell phenotype characteristic of partial D category VI, but without anti-D in their serum. The relation to the 'classic' partial D category VI was investigated and is discussed, as is the observed serological heterogeneity of the partial D category VI group. Clinical consequences for the prevention of immunization of these subjects are mentioned.

Antibodies, Monoclonal↗
PubMed1994

Sequence analysis of cDNA derived from reticulocyte mRNAs coding for Rh polypeptides and demonstration of E/e and C/c polymorphisms.

RNA derived from enriched reticulocytes of Rh-phenotyped donors was isolated, reversely transcribed into cDNA and amplified with Rh-specific primers by polymerase chain reaction. Nucleotide sequence analysis of the entire coding region of the Rh cDNAs was carried out. Four types of cDNAs were identified, tentatively designated as RhSCI, RhSCII, RhSCIII and RhSCIV. Comparison of RhSCII with RhSCI (identical to the previously reported RhIXb/30A cDNA), showed single base pair difference. Since RhSCI and RhSCII were found to be related to the presence of E or e antigen, respectively, the P226A amino acid polymorphism appears to be the genetic basis of the E/e polymorphism. RhSCIII was demonstrated to be a transcript derived from the RhD gene, with 35 amino acid substitutions as compared to RhSCI. RhSCIV was found to be present only in RhC-positive individuals, indicating that RhSCIV encodes a polypeptide carrying the C antigen. Six nucleotide changes, resulting in four amino acid substitutions W16C, L60I, N68S and P103S, were observed between RhSCII and RhSCIV, probably representing the C/c polymorphism.

Amino Acid Sequence↗
PubMed1993

Quantitation of D sites on selected 'weak D' and 'partial D' red cells.

Measurements have been made of the number of available sites on 10 examples of red cells in which the only abnormality appeared to be a quantitative reduction in the expression of D (weak D cells); these estimates were carried out using three monoclonal anti-D antibodies, Fog-1, Brad-3 and Los-2. The values varied with the monoclonal antibody that was used and fell within the range of 170-1,870 sites/cell. A further 3 examples of weak D cells which had brought about immunisation following transfusion were found to have between 390 and 1,470 sites per red cell. The implications of the D site density on the immunogenicity of weak D cells are discussed. The number of sites on red cells with structurally abnormal D (partial D cells) were also estimated, using the antibody Fog-1. Four of the 5 examples of cells of category IVa (probable phenotype Ror) were found to have a high expression of D (range 29,300-41,300), but the available D sites of categories DVa, DVIa, and DVII were considerably reduced (< 500, < 500 and 2,400-7,500 sites/cell, respectively). As a working hypothesis, it is suggested that there are two types of genetic abnormality leading to an abnormal expression of D. First, a defect in genomic DNA leading only to a quantitative reduction in the number of available D sites; this genomic lesion should be termed 'weak D'. Secondly, genomic defects leading to amino acid sequence abnormalities and structural change in the D polypeptide; these lesions should be collectively known as 'partial D'.

Antibodies, Monoclonal↗
PubMed1992

Protection against immune haemolytic disease of newborn infants by maternal monocyte-reactive IgG alloantibodies (anti-HLA-DR).

The extent to which maternal anti-Rh(D) antibodies support lysis of erythrocytes by monocytes in the antibody-dependent cell-mediated cytotoxicity (ADCC) assay is closely correlated with the severity of Rh(D) haemolytic disease of the newborn infant (HDN). However, in some cases HDN is much milder than would be predicted from the ADCC value. We postulated that maternal ADCC-blocking alloantibodies against paternal antigens on monocytes can protect these infants against severe haemolysis. We studied 13 severely Rh(D)-alloimmunised mothers whose infants showed unexpectedly mild HDN (group I) and 14 women with similar ADCC values but whose infants had severe HDN (group II). 7 group-I women had monocyte-reactive IgG alloantibodies that inhibited lysis by paternal monocytes in the ADCC. No such antibodies were found in group II (p less than 0.01). In 6 of the 7 serum samples with monocyte-reactive antibodies, the antibodies had HLA-DR specificity. Our findings suggest that Rh(D)-positive children of some severely Rh(D)-alloimmunised women may be protected from severe HDN by maternal non-HLA-class-I, IgG alloantibodies against paternal monocyte blood-group antigens. These antibodies may inhibit the mononuclear phagocyte system of the fetus.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1992

Misleading results in the determination of haemolytic disease of the newborn using antibody titration and ADCC in a woman with anti-Lub.

The Lutheran blood group system consists of several genes of which Lua and Lub are the best characterized. Over 98% of the Western population is Lu (b+), and consequently antibody formation against Lub is rare. Cases reported in the literature suggest that the expression of Lutheran antigens on red cells of the newborn is weak, and Lutheran antibodies are not known to have caused severe haemolytic disease of the newborn. We describe a case of anti-Lub immunization during pregnancy. Despite increasing anti-Lub antibody titre and antibody-dependent, cell-mediated cytotoxic activity of the anti-Lub, two parameters associated with haemolytic disease of the newborn, the baby did not suffer from erythroblastosis.

Adult↗
PubMed1990

[Revised definition of the concept rhesus-negative blood donor; practical experiences].

In 1987 the Central Medical Blood-transfusion Committee of the Netherlands Red Cross decided to modify their definition of 'Rh-negative' as it applied to blood donors. Until then the term Rh-negative had been reserved for donations that grouped as C- and E-negative and failed to react with IgG anti-D by the indirect antiglobulin test (IAT). From June 1987, however, donations were considered to be Rh-negative if they failed to react with two strong anti-D sera. An evaluation is presented over the first one and a half years of working with the new definition, the problems that were encountered and the measures that are taken to guarantee the quality of Rh testing.

Blood Banks↗