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Biomedical subjects

M E Reid

Publications and source records attributed to M E Reid.

At least 163 records · Page 9Linked to original sources
PubMed1993

Anti-Uz found in mother's serum and child's eluate.

A saline-reactive antibody, anti-Uz, that reacted stronger with S+ than with S- red blood cells (RBCs) and failed to react with U- or ficin-treated RBCs has been previously reported. We describe an antibody of similar specificity in the postpartum serum of an untransfused woman and the eluate from her fourth child's cord RBCs. The mother's RBCs typed S-s+U+, He+(weak), and appeared to have normal glycophorin A and B content, as deter- mined by immunoblotting. The direct antiglobulin test (DAT) and the autocontrol were negative. Her serum reacted stronger with S + RBCs only in the antiglobulin phase, and failed to react with U- or ficin-treated RBCs. The antibody was adsorbed completely by S-s+U+ RBCs, proving that anti-S was not present. Monocyte monolayer assay results with S+s-U+ and S-s+U+ RBCs indicated that transfusion of incompatible blood would not result in significant hemolysis. The child's cord RBCs typed S-s+. The DAT was 3+ with anti-IgG, and an eluate prepared from these RBCs had the same reactivity as the maternal serum. The child showed no clinical signs of hemolytic disease of the newborn. In contrast to previous reports, these results suggest an immune form of anti-Uz.

Journal Article↗
PubMed1992

Autoimmune hemolytic anemia associated with anti-Sc1.

A case of autoimmune hemolytic anemia (AIHA) in a young child is described. The hemolysis was resistant to steroid therapy but responded to splenectomy and intravenous immunoglobulin. The autoantibody was shown to be anti-Sc1 by both serologic and immunoblotting techniques. This seems to be the first report of an autoanti-Sc1 detected by immunoblotting and the first example of AIHA in a child caused by autoanti-Sc1.

Anemia, Hemolytic, Autoimmune↗
PubMed1992

Identification of autoantigens in autoimmune haemolytic anaemia by a non-radioisotope immunoprecipitation method.

In human autoimmune anaemia (AIHA), warm autoantibodies frequently appear to have serological specificity for the Rh complex, but to date, immunochemical techniques have failed to demonstrate that the antibodies react with Rh-associated polypeptides. We describe the immunoprecipitation of red blood cell (RBC) autoantigens, using biotin labelling and a luminescent detection method. In three cases of warm AIHA, a band of 32 kD and a diffuse zone of 38-51 kD or 40-51 kD were specifically precipitated by eluted RBC autoantibody. This pattern corresponds closely with that precipitated by two Rh-specific monoclonal antibodies, BRIC 207 and AB5. Antibody from the three eluates also showed serological specificity for the Rh complex in a haemagglutination assay against a panel of RBC with a range of Rh phenotypes, including rare -D-/-D- and Rh null cells. Eluted autoantibody from another warm AIHA patient immunoprecipitated a peptide of 67 kD that did not correspond in apparent molecular mass either with Rh-associated bands, or with major RBC membrane proteins or sialoglycoproteins (SGP). The haemagglutination assay showed that this eluate contained both Rh-specific and Rh-unrelated antibody. Warm autoantibody eluted from the RBC of a clinically normal, but direct antiglobulin test positive, blood donor was serologically unreactive with the Rh complex, and immunoprecipitated unknown peptides of 26, 29, 35, 48 and 51 kD, together with a band of 90 kD that comigrated with SGP alpha 2 (glycophorin A). In six further warm AIHA cases, no antigens were precipitated by autoantibody-containing RBC eluates. Overall, the results demonstrate that autoantibodies bind to Rh polypeptides in some, but not all, patients with warm AIHA, suggesting that the aetiology of the disease may vary.

Adult↗
PubMed1992

Point mutation in the glycophorin C gene results in the expression of the blood group antigen Dha.

The blood group Duch (Dha) antigen is located on glycophorin C (GPC). Total RNA prepared from the reticulocyte fraction of two Dh(a+) individuals were used in the synthesis of first-strand cDNA. The first-strand cDNA served as templates for the amplification of GPC-related DNA by polymerase chain reaction (PCR). The expected PCR product consisted of 412 base pairs. On sequencing the PCR-amplified DNA, a base change (cytosine----thymidine) at nucleotide 40 of the GPC cDNA was detected. Thus, the variant GPC (GPC.Dha) on Dh(a+) red cells has a substitution of leucine by phenylalanine at amino acid residue 14.

Base Sequence↗
PubMed1992

TSEN: a novel MNS-related blood group antigen.

We report an antibody (anti-TSEN) that recognizes an antigen (TSEN) at the unique amino acid sequence that results from the junction of GPA58 to GPB27 if the GPB carries the S antigen. Red cells from several unrelated donors that possess this specific GP(A-B) hybrid molecule were agglutinated by anti-TSEN. Since a synthetic peptide with the amino acid sequence at this junction (Pro-Glu-Glu-Glu-Thr-Gly-Glu-Met-Gly-Gln-Leu-Val-His-Arg) specifically inhibited anti-TSEN, it must detect an antigen within this novel amino acid sequence. The TSEN antigen has been provisionally assigned the MNS blood group system number 002.033 on behalf of the ISBT Working Party on Terminology for Red Cell Surface Antigens.

Adult↗
PubMed1992

MINY: a novel MNS-related blood group antigen.

We report an antibody (anti-MINY) that recognises a novel low-incidence MNS-related blood group antigen. Anti-MINY agglutinates all Hil-positive red cells tested (Mi.III, Mi.V, Mi.VI, GP.Kipp, GP.Mor and AG) and Hil-negative TSEN-positive red cells (Mi.IV, JR, JL, Oca. and Rag.). All MINY-positive red cells possess glycophorin A-B hybrid molecules. The MINY antigen occurs at the unique amino acid sequence which results from the junction of glycophorin A58 to glycophorin B27 regardless of whether the glycophorin B gene encodes methionine or threonine at amino acid residue 29 of normal glycophorin B. The MINY antigen has been provisionally assigned the MNS blood group system number 002.034 on behalf of the ISBT Working Party on Terminology for Red Cell Surface Antigens.

Amino Acid Sequence↗
PubMed1992

A Polynesian family showing co-dominant inheritance of normal glycophorin C and the Gerbich variant form of glycophorin C.

Two individuals with the rare Ge:-2-3,4 phenotype (Gerbich type of Gerbich negative) were identified in a family of Polynesian descent who reside in the Cook Islands. In initial serologic tests, all other family members typed as Ge-positive, and heterozygous individuals could not be identified. Further studies on blood samples from seven members of this Polynesian family by immunoblotting and hemagglutination tests on trypsin-treated red blood cells showed that normal glycophorin C and the product of the Gerbich allele were inherited in an autosomal dominant manner.

Journal Article↗
PubMed1991

Biochemical studies on red blood cells from a patient with the Inab phenotype (decay-accelerating factor deficiency).

A 38-year-old Russian woman (KZ) has been identified as the fourth proposita with the Inab blood group phenotype. Like the first two propositi, she has a chronic intestinal disorder and, as shown for the third proposita, her Inab phenotype is demonstrably inherited. KZ's serum contained anti-IFC, which reacted with a red blood cell (RBC) membrane component with an Mr of 70,000, which is decay accelerating factor (DAF). Her RBCs lacked all Cromer-related blood group antigens and DAF. Her RBCs were no more susceptible than normal control RBCs to lysis in acid lysis or in rabbit or human antibody-initiated complement lysis tests. Northern blots of total RNA isolated from KZ's Epstein-Barr virus-transformed lymphoblasts showed a marked reduction of DAF mRNA when compared with normal. Polymerase chain reaction (PCR) amplification of cDNA confirmed this reduced level of DAF mRNA. Sequencing of the PCR product showed a 44-nucleotide deletion in the mRNA close to the short consensus repeats IIIa/IIIb intron/exon boundary. This deletion results in a change in the reading frame that places a termination codon six amino acids after the deletion. The putative translation product would lack a glycosyl phosphatidyl-inositol linkage site and, therefore, would not be membrane-bound in the RBC.

Adult↗
PubMed1991

Molecular characterization of erythrocyte glycophorin C variants.

Human erythrocyte glycophorin C plays a functionally important role in maintaining erythrocyte shape and regulating membrane mechanical stability. Immunochemical and serologic studies have identified a number of glycophorin C variants that include the Yus, Gerbich, and Webb phenotypes. We report here the molecular characterization of these variants. Amplification of glycophorin C mRNA from the Yus phenotype, using two oligonucleotide primers that span the coding domain, generated a 338-bp fragment compared with a 395-bp fragment generated by amplification of normal glycophorin C mRNA. Sequencing of the mutant 338-bp fragment identified a 57-bp deletion that corresponds to exon 2 of the glycophorin C gene. Similar analysis showed deletion of 84-bp exon 3 in the Gerbich phenotype. In contrast to the generation of shorter than normal DNA fragments from mRNA amplification in the Yus and Gerbich phenotypes, amplification of mRNA from the Webb phenotype generated a normal-sized fragment. Sequencing of this DNA fragment showed an A----G substitution at nucleotide 23 of the coding sequence, resulting in the substitution of asparagine by serine. This modification accounts for the altered glycosylation of glycophorin C seen in this phenotype. These results have enabled us to characterize glycophorin C variants in three different phenotypes that involve deletions of exons 2 and 3 of the glycophorin C gene, as well as a point mutation in exon 1 that results in altered glycosylation of this protein.

Amino Acid Sequence↗
PubMed1991

Evidence that the human blood group antigens Gya and Hy are carried on a novel glycosylphosphatidylinositol-linked erythrocyte membrane glycoprotein.

Immunoblotting under non-reducing conditions with purified human anti-Gya and anti-Hy locates both antigens to an erythrocyte membrane glycoprotein of apparent Mr 46,750-57,500. The antigens are destroyed on intact red cells by the enzymes pronase, trypsin and chymotrypsin, and by treatment with reducing agents. Immunoblotting with anti-Gya and anti-Hy to membranes prepared from red cells pre-treated with an Endo F preparation caused a mean reduction in apparent Mr of the glycoprotein by 11 kDa at the leading and trailing edges, when compared with control membranes. These results suggest that the glycoprotein has one or more complex N-glycans that are not completely sensitive to Endo F digestion on intact cells. The majority of Gya/Hy-active molecules are not tightly associated with the red cell membrane skeleton. A gross reduction in reactivity with anti-Gya and anti-Hy by immunoblotting was observed in red cell membranes from patients with paroxysmal nocturnal haemoglobinuria, suggesting a possible membrane linkage via glycosylphosphatidylinositol for the glycoprotein that carries the Gya and Hy antigens. Immunoprecipitation of the glycoprotein by anti-Gya showed that the protein migrates faster under reducing conditions (Mr 45,000-54,000). A putative dimer was also evident in the precipitates. The glycoprotein was demonstrated to be distinct from lymphocyte-function-associated antigen-3 (CD58), the LWab-active glycoprotein, the Fya-active glycoprotein, the Oka-active glycoprotein and the BRIC 125 glycoprotein (CD47).

Antibodies, Monoclonal↗
PubMed1991

Evaluation of bovine serum albumin preparations and Ficoll addition in capillary tube hemagglutination.

Eighteen commercial bovine serum albumin (BSA) preparations were evaluated for their efficacy in hemagglutination enhancement by the capillary tube method. Their physicochemical variables (pH, conductivity, free fatty acids, total protein, and polymer content) were quantified. The results showed that a BSA preparation which consistently performed well in hemagglutination enhancement contained some albumin polymer and had a low free fatty acid content. We also found that the addition of Ficoll (final concentration of 1.24%) could convert BSA preparations producing mediocre hemagglutination enhancement into good enhancers, provided that these preparations did not have high free fatty acid content. Hence, the addition of Ficoll can obviate the requirement for selecting a polymer-enhanced albumin for use in capillary tube tests.

Animals↗
PubMed1990

Glycophorin C content of human erythrocyte membrane is regulated by protein 4.1.

Human erythrocyte transmembrane sialoglycoprotein, glycophorin C, plays a functionally important role in maintaining erythrocyte shape and regulating membrane material properties, possibly through its interaction with protein 4.1. Moreover, it has previously been shown that membranes deficient in protein 4.1 exhibit decreased content of glycophorin C. To further define the relationship between protein 4.1 and glycophorin C, a series of studies were performed using both protein 4.1- and glycophorin C-deficient erythrocytes. Quantitation by flow cytometry showed that the glycophorin C content of cells totally deficient in protein 4.1 was 9% of normal and that of cells partially deficient in protein 4.1 was 44% of normal. Interestingly, while homozygous glycophorin C-deficient cells had no detectable levels of this sialoglycoprotein, cells from obligate heterozygotes had normal levels. Protein 4.1 content of membranes of these glycophorin C-deficient cells was also normal. These data suggest that glycophorin C may be synthesized in excess by erythroid cells and its membrane content regulated by protein 4.1. To investigate if this regulation is due to association between protein 4.1 and glycophorin C, we examined the retention of glycophorin C in membrane skeletons (Triton shells) prepared from normal membranes, protein 4.1-deficient membranes, and protein 4.1-deficient membranes reconstituted with exogenous protein 4.1. Glycophorin C is retained by Triton shells prepared from normal membranes, whereas Triton shells prepared from protein 4.1-deficient membranes are totally devoid of this sialoglycoprotein. However, reconstitution of protein 4.1-deficient membranes with purified protein 4.1 resulted in retention of glycophorin C with the Triton shells. This finding suggests that protein 4.1 is necessary for association of glycophorin C with the membrane skeleton. Furthermore, these data suggest that through its interaction with glycophorin C, protein 4.1 may play a role in regulating the membrane content of this sialoglycoprotein in mature human erythrocytes.

Base Sequence↗
PubMed1990

Effects of deficiencies of glycophorins C and D on the physical properties of the red cell.

Red cells of the rare Leach phenotype lack the membrane glycophorins C and D, and a proportion of the red cells are elliptocytes. Judging from tests on suspensions of red cell ghosts sheared rotationally in an ektacytometer, it has previously been suggested that these membranes are relatively fragile and poorly deformable. We have carried out analyses of individual red cells to investigate possible factors which underlie the physical changes in these glycophorin-deficient cells. Micropipette analysis of the red cell membrane showed that the rigidity and viscosity were normal, both for elliptocytes and discocytes, for three donors deficient in glycophorins C and D. Red cell transit times through 5 microns pores, measured electronically for 2000 individual cells, showed no differences from controls. It was confirmed that the index of deformation obtained using an ektacytometer was reduced, but our results suggest that this arises from shape rather than membrane changes. The elliptocytes were found to have a lower volume and surface area than discocytes from the same donor (measured by micropipette aspiration of single red cells), and were rarely found in less dense red cell fractions. No reticulocytes were found to be elliptical. These data suggest that the elliptocytes are older red cells, and are formed from red cells which are initially released into the circulation with normal shape. Their elongated shape might arise from permanent distortion of the unstable membrane by shear forces in the circulation.

Elasticity↗
PubMed1990

Agglutination of red blood cells from patients with diabetes mellitus by a polyclonal human antibody specific for D-glucose.

We have previously described an antibody which will agglutinate red blood cells which had been incubated in vitro in D-glucose. This antibody is specific for the ring form of glucose, beta-D-glucopyranose. The current report demonstrates that without prior in vitro incubation with glucose, red blood cells from 36 of 38 patients with diabetes mellitus, and 7 of 70 patients not diagnosed as diabetic were agglutinated by this antibody. Strength of agglutination of red blood cells from diabetic patients correlated with both glucose (r = 0.61; p less than 0.001) and hemoglobin A1c levels (r = 0.50; p less than 0.01) in simultaneously obtained samples. This reactivity could be reversed by incubating red blood cells from diabetics for several hours in saline. This report suggests that red blood cells from diabetic patients have membrane-bound glucose that can be detected immunologically. Reversibility of the reaction and rapidity of in vitro glycosylation suggests short-term binding of glucose. To our knowledge, this is the first report documenting immunological detection of in vivo short-term reversible binding of glucose to cellular membranes.

Antibodies↗
PubMed1990

Serological and immunochemical specificity of a human autoanti-Gerbich-like antibody.

An 85-year-old male with cardiac failure secondary to anaemia had an apparent anti-Ge2 (Ge = Gerbich) in his serum which did not agglutinate his own red cells even though they were Ge-positive in tests with alloanti-Ge. The direct antiglobulin test was negative; however, an antibody with apparent anti-Ge2 specificity was eluted from his red cells. The patient's autoantibody was shown in immunoblotting experiments to react with an antigenic determinant on beta-sialoglycoprotein. This case illustrates that an autoanti-Ge can masquerade as an alloantibody, thereby complicating antibody identification, and implies that the immunochemical specificity of autoanti-Ge2 is different from that of alloanti-Ge2.

Aged↗