Publications by authors named "Christophe Tournamille"

Blood group antigens of the RH system (formerly known as "Rhesus") play an important role in transfusion medicine because of the severe haemolytic consequences of antibodies to these antigens. No crystal structure is available for RhD proteins with its partner RhAG, and the precise stoichiometry of the trimer complex remains unknown. To analyse their structural properties, the trimers formed by RhD and/or RhAG subunits were generated by protein modelling and molecular dynamics simulations were performed.

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Hundreds of articles containing heterogeneous data describe D variants or add to the knowledge of known alleles. Data can be difficult to find despite existing online blood group resources and genetic and literature databases. We have developed a modern, elaborate database for D variants, thanks to an extensive literature search with meticulous curation of 387 peer-reviewed articles and 80 abstracts from major conferences and other sources.

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Background: Many RhD variants associated with anti-D formation (partial D) in carriers exposed to the conventional D antigen carry mutations affecting extracellular loop residues. Surprisingly, some carry mutations affecting transmembrane or intracellular domains, positions not thought likely to have a major impact on D epitopes.

Study Design And Methods: A wild-type Rh trimer (RhD RhAG ) was modeled by comparative modeling with the human RhCG structure.

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Background: CD36 glycoprotein is expressed by various cell types, including platelets (PLTs), monocytes, and erythroid precursors, and is also the receptor for several ligands. However, absence of CD36 expression seems asymptomatic and is poorly described in Caucasians. In contrast, the frequency reaches 7% and 11% in African Caribbean and Asian persons, respectively.

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Background: In the novel era of blood group genomics, (re-)defining reference gene/allele sequences of blood group genes has become an important goal to achieve, both for diagnostic and research purposes. As novel potent sequencing technologies are available, we thought to investigate the variability encountered in the three most common alleles of , the gene encoding the clinically relevant Duffy antigens, at the haplotype level by a long-read sequencing approach.

Materials And Methods: After long-range PCR amplification spanning the whole gene locus (∼2.

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Background: Partial D status is a major concern for transfusion and pregnancy, due to the possibility of carriers becoming immunized. When known carriers of a D variant have never been exposed to complete D, they are assumed to have D partial status based on the position of the amino acid substituted. New approaches for predicting immunization risk are required.

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This review presents the French strategy for blood group genotyping in high-responder and newly diagnosed sickle cell disease (SCD) patients. In addition to , , and genotyping, the RH blood group system is now explored in SCD patients in France. Molecular typing has been used for the deduction of partial RH2 (C) antigens since 2010, and the gradual implementation of systematic and genotyping nationwide was initiated in late 2014.

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Background: Sickle cell disease (SCD) patients undergo multiple red blood cell (RBC) transfusions and are regularly exposed to low-prevalence (LP) antigens specific to individuals of African descent. This study evaluated the prevalence of antibodies against LP antigens in SCD patients and the need to identify these antibodies in everyday practice.

Study Design And Methods: Plasma from 211 SCD patients was tested with RBCs expressing the following LP antigens: RH10 (V), RH20 (VS), RH23 (D ), RH30 (Go ), KEL6 (Js ), and MNS6 (He).

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Background: The RH blood group system has many RHCE variant alleles that have arisen through gene conversion or nucleotide changes. Two probands, with red blood cells (RBCs) that were D+C+E-c+(w) e+ were sent to our laboratories to resolve the weak c expression.

Study Design And Methods: Hemagglutination tests were performed by automated and manual procedures.

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Background: Partial Rh antigens have been widely described in black individuals. Carriers are prone to immunization when exposed to the normal antigens. In sickle cell disease (SCD), patient alloimmunization is a major cause of transfusion failure.

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Background: Weak D Types 1, 2, and 3 recipients cannot be immunized when exposed to D antigen. Molecular biology is very efficient to type weak D variants but rarely implemented in daily practice. The serologic typing practice of weak D in a Caucasian patient population was analyzed and a transfusion strategy is proposed.

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Background: It has long been known that relative immunogenicity is a characteristic of protein red blood cell (RBC) antigens, but the mechanisms remain unclear. The aim of this work was to elucidate the mechanisms underlying this relative immunogenicity.

Study Design And Methods: Two RBC antigens were used as a model--the highly immunogenic K antigen (KEL1) and the less immunogenic Fya antigen (FY1)--and analyzed the distribution of DRB1* molecules in two groups of Caucasian individuals producing anti-Fya (n = 29) or anti-K (n = 30) alloantibodies.

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Background: Antibodies against RH antigens are clinically significant. Some rare RH phenotypes, for example, RH:-46 (R(N)), RH:-18 (Hr(s)-), RH:-34 (Hr(b)-), and homozygous partial RH5 (e), are found exclusively in black persons of African descent. Quantitative and qualitative RHCE variants require characterization because the presence of these alleles can lead to difficulties when transfusion is needed.

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The Duffy antigen/ receptor for chemokine, DARC, acts as a widely expressed promiscuous chemokine receptor and as the erythrocyte receptor for Plasmodium vivax. To gain insight into the evolution and structure/function relations of DARC, we analyzed the binding of anti-human Fy monoclonal antibodies (mAbs) and human chemokines to red blood cells (RBCs) from 11 nonhuman primates and two nonprimate mammals, and we elucidated the structures of the DARC genes from gorilla, gibbon, baboon, marmoset, tamarin, night monkey and cattle. CXCL-8 and CCL-5 chemokine binding analysis indicated that the promiscuous binding profile characteristic of DARC is conserved across species.

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The Duffy antigen/receptor for chemokines (DARC), a seven-transmembrane glycoprotein carrying the Duffy (Fy) blood group, acts as a widely expressed promiscuous chemokine receptor. In a structure-function study, we analysed the binding of chemokines and anti-Fy monoclonal antibodies (mAbs) to K562 cells expressing 39 mutant forms of DARC with alanine substitutions spread out on the four extracellular domains (ECDs). Using synthetic peptides, we defined previously the Fy6 epitope (22-FEDVW-26), and we characterized the Fya epitope as the linear sequence 41-YGANLE-46.

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