Lola Svensson

Intravenous synthetic alphaGal saccharides delay hyperacute rejection following pig-to-baboon heart transplantation.

Romano E, Neethling FA, Nilsson K, Kosanke S, Shimizu A, Magnusson S, Svensson L, Samuelsson B, Cooper DKC Intravenous synthetic αgal saccharides delay hyperacure rejection following pig‐to‐baboon heart transplantation. Xenotransplantation 1999; 6: 00‐00

DNA Sequencing and Screening for Point Mutations in the Human Lewis (FUT3) Gene Enables Molecular Genotyping of the Human Lewis Blood Group System

The human Lewis gene encodes an α(1,3/1,4)‐fucosyltransferase responsible for synthesis of the Lea and Leb antigens. To define the molecular background for non‐functional Lewis genes we have sequenced PCR‐amplified DNA fragments from two Le(a‐b‐) individuals. One was homozygously mutated at nucleotides 202 (T→C) and 314 (C→T), altering Trp68 to Arg and Thrl05 to Met, and the other was homozygously mutated at nucleotides 59 (T→G) and 1067 (T→A), altering Leu20 to Arg and Ile356 to Lys. Using PCR we screened for these and additionally one other mutation atnucleotide 508 (G→A) among 40 Caucasians. Of 15 Le(a‐b‐) individuals, 7 typed as le59/1067 le202/314, 4 as le202/314le202/314 and 1 as le59/10671e59/1067. Of 21 Le(a‐b+) and 4 Le(a+b‐), 17 typed as LeLeand 7 as Lele202/314. A pedigree study of 8 Lewis‐positive individuals showed that the mutations at nucleotides 202 and 314 were located on the same allele.

Forssman expression on human erythrocytes: biochemical and genetic evidence of a new histo-blood group system

In analogy with histo-blood group A antigen, Forssman (Fs) antigen terminates with α3-N-acetylgalactosamine and can be used by pathogens as a host receptor in many mammals. However, primates including humans lack Fs synthase activity and have naturally occurring Fs antibodies in plasma. We investigated individuals with the enigmatic ABO subgroup A(pae) and found them to be homozygous for common O alleles. Their erythrocytes had no A antigens but instead expressed Fs glycolipids. The unexpected Fs antigen was confirmed in structural, serologic, and flow-cytometric studies. The Fs synthase gene, GBGT1, in A(pae) individuals encoded an arginine to glutamine change at residue 296. Gln296 is present in lower mammals, whereas Arg296 was found in 6 other primates, > 250 blood donors and A(pae) family relatives without the A(pae) phenotype. Transfection experiments and molecular modeling showed that Agr296Gln reactivates the human Fs synthase. Uropathogenic E coli containing prsG-adhesin-encoding plasmids agglutinated A(pae) but not group O cells, suggesting biologic implications. Predictive tests for intravascular hemolysis with crossmatch-incompatible sera indicated complement-mediated destruction of Fs-positive erythrocytes. Taken together, we provide the first conclusive description of Fs expression in normal human hematopoietic tissue and the basis of a new histo-blood group system in man, FORS.

Typing for the Human Lewis Blood Group System by Quantitative Fluorescence–Activated Flow Cytometry: Large Differences in Antigen Presentation on Erythrocytes between A1, A2, B, O Phenotypes

Background: Lewis phenotyping by hemagglutination is an unreliable routine method for Lewis antigen designation. Now genomic typing of the Lewis gene is available. Additionally, flow cytometry has been used for typing. We wanted to compare the results of Lewis typing in healthy individuals using the three methods. Materials and Methods: Ninety–three randomly selected plasma donors were genotyped for inactivating Secretor (FUT2) G428A and Lewis (FUT3) T59G, T202C, C314T, G508A and T1067A point mutations. All Le(a+b–) individuals (nonsecretors) were homozygous for the FUT2 G428A mutation and all Le(a–b–) individuals had inactivating mutations on both FUT3 alleles. Fixed erythrocytes were analyzed by fluorescence–activated flow cytometry and the results were compared with hem– agglutination and genotypic data. Antigen availability was expressed as median fluorescence intensity and as percentage positive cells with fluorescence intensities ≥102. Results: Using an anti–Lea reagent a mean of 99% of erythrocytes from Le(a+b–) individuals and 1% of erythrocytes from Le(a–b–) or Le(a–b+) individuals were stained positive. Using an anti–Leb reagent, a mean of 71% of erythrocytes from A1, 95% from B and 99% from O and A2 Le(a–b+) individuals and less than 10% of erythrocytes from Le(a–b–) or Le(a+b–) individuals were stained positive. After papain treatment 100% of the erythrocytes from A1 and A1B Le(a–b+) individuals stained positive without increase in background staining. The flow cytometric technique revealed large differences in staining intensities, within each ABO Le(a–b+) subgroup which was not directly correlated to plasma donation frequencies nor to Secretor or Lewis genotypes. Conclusion: Flow cytometry may prove valuable as a Lewis blood group typing technique but also as a research tool when investigating Lewis phenotypes of human erythrocytes.

Nomenclature of Granulocyte Alloantigens

and the detection of new ones has made a new nomenclature for these antigens necessary. Neutrophil alloantibodies are known to cause neonatal alloimmune neutropenia, immune neutropenia after bone marrow transplantation, refractoriness to granulocyte transfusions, and severe transfusion-related acute lung injury. With respect to the increasing use of granulocyte transfusions this is of special importance, since alloimmunization to granulocyte antigens can decrease the recovery and half-life of transfused granulocytes, can prevent their migration to sites of infection and can cause severe pulmonary transfusion reactions. The Granulocyte Antigen Working Party of the ISBT agreed at their meeting in S’Agaró, Spain, in 1998, to establish a new nomenclature system for well-defined neutrophil alloantigens, which is based on the following rules: (1) Neutrophil antigens are to be called HNA for ‘human neutrophil antigen(s)’. (2) MemISBT Working Party

Blood group A1 and A2 revisited: an immunochemical analysis

Background and Objective  The basis of blood group A1 and A2 phenotypes has been debated for many decades, and still the chemical basis is unresolved. The literature generally identifies the glycolipid chemical differences between blood group A1 and A2 phenotypes as being poor or no expression of A type 3 and A type 4 structures on A2 red cells, although this assertion is not unanimous.

Secretor genotyping for A385T, G428A, C571T, C628T, 685delTGG, G849A, and other mutations from a single PCR.

BACKGROUND: The secretor status of an individual is important for disease relationship studies, because it determines the presence of ABH blood group antigens in the gastrointestinal tract and bodily secretions. Routine serologic methods for determining secretor status are unreliable. Current strategies based on PCR for genotyping require relatively large amounts of DNA and have to be done as several separate experiments.

Novel glycolipid variations revealed by monoclonal antibody immunochemical analysis of weak ABO subgroups of A

Background and Objectives  The chemical basis of the subgroups of A is largely unknown. We used thin‐layer chromatography immunochemical staining techniques together with a range of characterized monoclonal reagents to analyse glycolipids isolated from a variety of weak subgroups.

The structural basis of blood group A related glycolipids in an A3 red cell phenotype and a potential explanation to a serological phenomenon

Glycolipids from the red cells of a rare blood group A subgroup individual, expressing the blood group A(3) phenotype with the classical mixed-field agglutination phenomenon, A(2(539G>A))/O(1) genotype, and an unusual blood group A glycolipid profile, were submitted to a comprehensive biochemical and structural analysis. To determine the nature of blood group A glycolipids in this A(3) phenotype, structural determination was carried out with complementary techniques including proton nuclear magnetic resonance (1D and 2D), mass spectrometry (MS) (nano-electrospray ionization/quadrupole time-of-flight and tandem mass spectrometry) and thin layer chromatography with immunostaining detection. As expected, total blood group A structures were of low abundance, but contrary to expectations extended-A type 2 and A type 3 glycolipids were more dominant than A hexaglycosylceramides based on type 2 chain (A-6-2 glycolipids), which normally is the major A glycolipid. Several para-Forssman (GalNAcβ3GbO(4)) structures, including extended forms, were identified but surmised not to contribute to the classic mixed-field agglutination of the A(3) phenotype. It is proposed that the low level of A antigen combined with an absence of extended branched glycolipids may be the factor determining the mixed-field agglutination phenomenon in this individual.

Glycolipid- and glycoprotein-based blood group A antigen expression in human thrombocytes. A1/A2 difference

Total non-acid glycolipid fractions and total sodium dodecylsulphate (SDS) solubilized protein fractions were isolated from human thrombocytes obtained from single human donors having different blood group A1/A2 phenotypes. The blood group A glycolipid antigens were characterized by immunostaining of thin layer plates with different monoclonal anti-A antibodies. The glycoproteins carrying blood group A epitopes were identified by SDS-PAGE and Western blot analysis using a monoclonal anti-A antibody. Blood group A glycolipid antigens were found in both A1 and A2 thrombocytes but the A2 individuals expressed at least ten times less A glycolipids compared to the A1 individuals. Expression of A type 3/4 chain and small amounts of A type 1 chain glycolipids were seen in thrombocytes of both A1 and A2 individuals, while the type 2 chain A glycolipids appeared to be missing from the A2 thrombocytes. Blood group A reactive glycoproteins were only found in thrombocytes of A1 individuals and could not be detected in A2 individuals or a blood group O individual. The major blood group A glycoprotein were found as a double band migrating in the 130 kDa region.