Body-wide chimerism and mosaicism are predominant causes of naturally occurring ABO discrepancies.

Routine ABO blood group typing of apparently healthy individuals sporadically uncovers unexplained mixed-field reactions. Such blood group discrepancies can either result from a haematopoiesis-confined or body-wide dispersed chimerism or mosaicism. Taking the distinct clinical consequences of these four different possibilities into account, we explored the responsible cause in nine affected individuals.

Management of a pregnant woman with anti-holley alloantibody.

Background: Holley (Hy) is a high-incidence antigen of the Dombrock blood group system (ISBT 014), present in almost 100% of most populations and more than 99% of Blacks. Since anti-Hy is an extremely rare antibody, data on its clinical relevance and in particular on a possible hemolytic disease of the fetus and newborn (HDFN) are scarce.

Case Report: The pregnant patient underwent two autologous whole blood collections at weeks 17 and 19 of gestation with cryopreservation.

Lack of the nucleoside transporter ENT1 results in the Augustine-null blood type and ectopic mineralization.

The Augustine-negative alias At(a-) blood type, which seems to be restricted to people of African ancestry, was identified half a century ago but remains one of the last blood types with no known genetic basis. Here we report that a nonsynonymous single nucleotide polymorphism in SLC29A1 (rs45458701) is responsible for the At(a-) blood type. The resulting p.

Implementation of a mandatory donor RHD screening in Switzerland.

Starting in 2013, blood donors must be tested at least using: (1) one monoclonal anti-D and one anti-CDE (alternatively full RhCcEe phenotyping), and (2) all RhD negative donors must be tested for RHD exons 5 and 10 plus one further exonic, or intronic RHD specificity, according to the guidelines of the Blood Transfusion Service of the Swiss Red Cross (BTS SRC). In 2012 an adequate stock of RHD screened donors was built. Of all 25,370 RhD negative Swiss donors tested in 2012, 20,015 tested at BTS Berne and 5355 at BTS Zürich, showed 120 (0.

Molecular RHD screening of RhD negative donors can replace standard serological testing for RhD negative donors.

This work aims to assess the value of a generalized molecular RHD screening strategy which could replace routine serological screening of weak D by indirect antiglobulin test. Three independent studies were performed at the two Blood Transfusion Services Berne and Zurich. Donors investigated were 652 RhD negative, but RhC and/or RhE positive, 17,391 mainly Rhccee, and 8200 with normal RhCcEe phenotype distribution.

Serologic and molecular investigations of DAR1 (weak D Type 4.2), DAR1.2, DAR1.3, DAR2 (DARE), and DARA.

Background: The partial D variant DAR1 (weak D Type 4.2) is caused by three single-point mutations, 602C>G, 667T>G, and 1025T>C. Here we report a molecular study on different D variants belonging to the DAR category (DAR1, DAR1.

A novel B(weak) hybrid allele lacks three enhancer repeats but generates normal ABO transcript levels.

Background And Objectives: Weak expression of A/B histo-blood group antigens is often explained by single nucleotide substitutions at the ABO locus. However, hybrid alleles containing segments from different ABO alleles can result in unexpected phenotypes and may complicate genotype analysis. We investigated the basis of weak B phenotype in a referred sample.

Molecular basis of the Rh antigen RH48 (JAL).

Background And Objectives: RH48 (JAL) is a low-incidence Rh antigen of unknown molecular background associated with weakened expression of RhCE antigens. The objective of this study was to establish the molecular basis of JAL.

Materials And Methods: Seventeen JAL+ samples, from seven black (one of them a Brazilian of mixed race: black/Caucasian), nine European Caucasians and one Asian individuals, were typed with anti-D, -C, -c, -E and -e.

Structural basis for red cell phenotypic changes in newly identified, naturally occurring subgroup mutants of the human blood group B glycosyltransferase.

Background: Four amino-acid-changing polymorphisms differentiate the blood group A and B alleles. Multiple missense mutations are associated with weak expression of A and B antigens but the structural changes causing subgroups have not been studied.

Study Design And Methods: Individuals or families having serologically weak B antigen on their red cells were studied.

The molecular diversity of Sema7A, the semaphorin that carries the JMH blood group antigens.

Background: Semaphorin 7A (Sema7A), the protein that carries the JMH blood group antigen, is involved in immune responses and plays an important role in axon growth and guidance. Because previous serologic studies on red blood cells (RBCs) suggested a considerable diversity of Sema7A, the present study was designed to elucidate the complex picture of the molecular diversity of this protein.

Study Design And Methods: The JMH antigen status was determined by serology, flow cytometry, and Western blot.

In-frame triplet deletions in RHD alter the D antigen phenotype.

Background: The deletion of three adjacent nucleotides in an exon may cause the lack of a single amino acid, while the protein sequence remains otherwise unchanged. Only one such in-frame deletion is known in the two RH genes, represented by the RHCE allele ceBP expressing a "very weak e antigen."

Study Design And Methods: Blood donor samples were recognized because of discrepant results of D phenotyping.

Identification of six new alleles at the FUT1 and FUT2 loci in ethnically diverse individuals with Bombay and Para-Bombay phenotypes.

Background: The Bombay and para-Bombay phenotypes arise from mutations of the FUT1 gene that silence the gene or affect the efficiency of the encoded 2-alpha-fucosyltransferase. Samples from seven individuals of different geographic backgrounds whose red blood cells had an apparent Bombay or para-Bombay phenotype were investigated. Among these, novel FUT1 and FUT2 alleles were identified.