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Papers by Philippe Rouger

Research paper thumbnail of Évaluation du portfolio électronique et de son système d’accompagnement dédié à l’évaluation des pratiques professionnelles en technique et médecin e transfusionnelles

Informatique et Santé, 2009

Abstract In order 10 help physicians to meet the compulsory evaluation of professional practices ... more Abstract In order 10 help physicians to meet the compulsory evaluation of professional practices as regards blood transfusion, the French National Blood Transfusion Institute and the University of Nice imagined a structured and accompanied eportfolio available on the Internet, This innovative system, faced up problem of the approval of an implement of new technology intended for a specific professional environment.

Research paper thumbnail of Using a C-Terminal Fragment of C4Binding Protein A Recombinant Human scFv AntiRh(D) Antibody With Multiple Valences

Research paper thumbnail of Flow cytometric evaluation of human basophils

Cytometry, 1993

The expression of CD45 and IgE cell surface antigens on human leucocytes was studied by flow cyto... more The expression of CD45 and IgE cell surface antigens on human leucocytes was studied by flow cytometry. More than 80% of sorted cells that expressed low CD45 (CD45dim) and high IgE (IgEbright) antigen site density were identified as basophils. Immunomagnetic depletion of the CD45dim-IgEbright cell subset by a biotin-coupled anti-IgE antibody and streptavidin-coated magnetic beads was greater than 90%, and more than 80% of cells binding significant numbers of beads exhibited the morphological characteristics of basophils. Interestingly, when the cell staining was performed in the presence of calcium and magnesium, we observed a significant increase of CD45 and an equivalent decrease of IgE cell surface expression, as well as an IgE concentration dependent diminution of the number of CD45dim-IgEbright cells.

Research paper thumbnail of Flow cytometric monitoring of allergen induced basophil activation

Cytometry, 1995

Human basophils express many clustered differentiation antigens (CD), including CD45; however, no... more Human basophils express many clustered differentiation antigens (CD), including CD45; however, none are specific for these cells. In a previous study, we described a two-color immunofluorescence procedure, employing antibodies to CD45 and IgE for the cytometric evaluation of basophils. In the present work, we show that when sensitized basophils are stimulated by allergenic preparations, they demonstrate an upregulation of CD45 as well as a decrease in anti-IgE binding. Since CD45 antigen modulation was observed with all aeroallergens tested and the decrease in IgE expression varied with allergenic preparations, the measurement of CD45 upregulation was used to evaluate basophil activation. Using this approach, reproducible results were observed when atopic patients were tested at different time intervals. In addition, we show that the upregulation of CD45 on allergen stimulated basophils is a very rapid phenomenon that is observed after a few minutes and that this rapid flow cytometr...

Research paper thumbnail of Human monoclonal antibody against Rh(D) antigen: partial characterization of the Rh(D) polypeptide from human erythrocytes

Blood, 1987

A human monoclonal anti-Rh(D) antibody produced by an Epstein-Barr virus (EBV)-transformed B-cell... more A human monoclonal anti-Rh(D) antibody produced by an Epstein-Barr virus (EBV)-transformed B-cell line (IgG1(lambda), clone H2D5D2) has been purified on protein A-Sepharose column and used for binding studies and immune precipitation of the blood group rhesus (Rh) antigens. Scatchard plot analyses show that the 125I-labeled antibody (iodo-gen procedure), binds to 1.09 X 10(5), 0.43 X 10(5), and 0.32 X 10(5) antigen sites on each D--/D--, R2R2 and R1R1 RBC, respectively, with an association constant of approximately 0.6 X 10(8) mol/L-1. Immune precipitation studies indicate also that the Rh(D) antigen of the Rh(D)-positive RBCs is carried by a 29 kd polypeptide as deduced from sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). No material could be precipitated from Rh(D)-negative or Rhnull RBCs. These results indicate that the monoclonal and the polyclonal human anti-Rh(D) behave similarly. A sample (Blo., presumed genotype R2r or R0R2) showing an increased number ...

Research paper thumbnail of « Lecture critique appliquée au vieillissement » L.-R. Salmi, M. Rainfray, J.-F. Dartigues. Éditions Elsevier

Research paper thumbnail of UN EPORTFOLIO STRUCTURÉ ET TUTORÉ POUR LA GESTION ET LE SUIVI PERSONNALISÉ DE L’EVALUATION DES PRATIQUES PROFESSIONNELLES EN TECHNOLOGIE ET MÉDECINE TRANSFUSIONNELLES

Research paper thumbnail of Professeur Jacques Ruffié (1921–2004)

Transfusion Clinique et Biologique, 2004

Research paper thumbnail of Fatal hemolytic disease of the fetus and newborn associated with anti-Jr a

Research paper thumbnail of Heterogeneous molecular background of the weak C, VS+, hr B -, Hr B - phenotype in black persons

Transfusion, 2009

The rare Hr B -phenotype is encoded by the (C)ce s haplotype when present at the homozygous state... more The rare Hr B -phenotype is encoded by the (C)ce s haplotype when present at the homozygous state. This haplotype contains two altered genes: a hybrid RHD-CE-D s gene segregated with a ce s allele of RHCE (733C>G and 1006G>T substitutions in Exon 5 and Exon 7 respectively). The aim of this study was to further investigate the molecular background of the (C)ce s haplotype. STUDY DESIGN AND METHODS: Twelve individuals with depressed C and/or depressed e phenotype were selected from their genomic DNA analysis showing both 733C>G and 1006G>T substitutions. Phenotypic expression of low-and high-prevalence Rh antigens was studied. Complete sequences of RHD and RHCE transcripts were analyzed when obtained.

Research paper thumbnail of Alloanti-c (RH4) revealing that the (C)ce s haplotype encodes a partial c antigen

Research paper thumbnail of Alloanti-c/ce in a c+ ceAR/Ce patient suggests that the rare RHCE*ceAR allele ( ceAR ) encodes a partial c antigen

Research paper thumbnail of Blood group genotyping by high-throughput DNA analysis applied to 356 reagent red blood cell samples

Transfusion, 2011

BACKGROUND: DNA analysis for the prediction of blood group antigen expression has broad implicati... more BACKGROUND: DNA analysis for the prediction of blood group antigen expression has broad implications in transfusion medicine. It may be of particular interest especially to detect variants, when antigen expression is weak or altered. The use of high-throughput DNA analysis has never been applied to donors whose red blood cells (RBCs) are selected for reagent RBCs. The aim of this study was to analyze the concordance between the serologic phenotype and that predicted from DNA analysis in panel donors, to determine the benefit of the use of DNA analysis in reagent RBC selection strategy.

Research paper thumbnail of HIV antibody screening remains indispensable for ensuring viral safety of blood components despite NAT implementation

Transfusion, 2003

The main objective of the implementation of NAT for the screening of blood-borne viruses was to c... more The main objective of the implementation of NAT for the screening of blood-borne viruses was to compensate for the failure of serologic assays during the window period. Because this new screening procedure theoretically covers the entire period of infectivity, the necessity for maintaining serologic assays in blood screening strategy could become questionable. To investigate this issue, a panel of 35 samples has been studied by NAT. These samples had been collected from HIV-1 antibody-positive individuals presenting a persistently low viral RNA load (<400 copies/mL) in the absence of antiviral therapy. All samples were analyzed with the minipool (x8) NAT routinely used in blood bank setting (HIV-1 and HCV assay based on transcription-mediated amplification) and with single-donation testing. The minipool NAT failed to detect the presence of HIV RNA in 15 of the 35 samples (11 remained negative when retested). Single-donation testing gave negative results in 4 samples (3 remained negative when retested). Fourteen of the 18 samples with a viral load greater than 50 copies per mL were positive by minipool NAT versus 6 of the 17 samples with fewer than 50 copies per mL (p = 0.02). The results clearly demonstrate that anti-HIV screening should not be withdrawn from biologic qualification procedures of blood donations, even when single NAT is performed.

Research paper thumbnail of Molecular background of D(C)(e) haplotypes within the white population

Transfusion, 2002

BACKGROUND: D(C)(e) and D(C)e haplotypes may be encountered in the white population. Few data are... more BACKGROUND: D(C)(e) and D(C)e haplotypes may be encountered in the white population. Few data are available on the molecular backgrounds responsible for depressed expression of C and e. STUDY DESIGN AND METHODS: Individuals of white origin carrying a D(C)(e) genotype resulting in depressed expression of C or both C and e were subdivided into two categories based on the RBC reactivity with the human sera Mol and Hor, which contain antibodies against low-frequency antigens of the Rh (RH) system and other non-Rh low-frequency antigens. Neither Hor+, Mol+ nor Hor+, Mol-RBCs expressed the V (RH10), VS (RH20), and/or Rh32 (RH32) low-frequency antigens. These results suggested that Hor+, Mol+ variants expressed Rh33 (RH33 or Har) and FPTT (RH50), whereas Hor+, Mol-variants might express an undefined low-frequency antigen. Further serologic and molecular analyses were performed. RESULTS: Molecular analysis of Hor+, Mol+ variants revealed a hybrid gene structure RHCe-D(5)-Ce, in which exon 5 of RHCE (RHCe allele) was replaced by exon 5 of RHD (the so-called RHCeVA allele). The presence of exon 5RHD resulted in several amino acid alterations predicted in the external loop 4 of the CeVA polypeptide. Molecular analysis of Hor+, Mol-variants revealed the presence of a new RHCe allele characterized by a single point mutation C340T within exon 3 (the so-called RHCeMA allele), resulting in a R114W substitution predicted on the external loop 2 of the CeMA polypeptide. A serologic study showed a different pattern of reactivity with C and e MoAbs. CONCLUSION: Two types of mutations resulted in amino acid substitutions predicted in external loops 4 and 2, respectively, which altered both the C and e reactivity, and indicated conformation changes or defective interaction between nonadjacent loops of the Ce polypeptide. Serologic analysis showed that together with Hor and Mol sera testing, the use of different C and e MoAbs could help to identify these variants within the white population. ABBREVIATION: SSP = sequence-specific primer.

Research paper thumbnail of Analysis of complement receptor Type 1 expression on red blood cells in negative phenotypes of the Knops blood group system, according to CR1 gene allotype polymorphisms

Transfusion, 2010

The KN blood group system, which consists of nine antigen specificities, is located on complement... more The KN blood group system, which consists of nine antigen specificities, is located on complement receptor Type 1 (CR1/CD35). CR1, a complement regulatory protein, acts as a vehicle for immune complex clearance. CR1 exhibits a red blood cell (RBC) density polymorphism. CR1 sites on RBCs in normal individuals range from 150 to 1200 molecules per cell. CR1 density polymorphism is regulated by HindIII restriction fragment length polymorphism and Q981H and P1786R polymorphisms in Caucasians. Yet, the role of the different polymorphisms in determining the CR1 density on RBCs remains unknown. The "null" serologic KN phenotype, known as Helgeson phenotype, was reported to be related with a very low CR1 density, less than 150 molecules per cell.

Research paper thumbnail of Anti-U-like as an alloantibody in S−s−U− and S−s−U+var black people

Research paper thumbnail of Anti-D investigations in individuals expressing weak D Type 1 or weak D Type 2: allo- or autoantibodies?

Transfusion, 2011

Whether anti-D produced by individuals with a weak D phenotype are allo- or autoantibodies remain... more Whether anti-D produced by individuals with a weak D phenotype are allo- or autoantibodies remains a matter of debate even though blood transfusion practice is impacted. The aim of our study was to determine the serologic features of anti-D in individuals expressing the most frequent weak D type in Caucasians that are weak D Type 1 or weak D Type 2, to assess whether anti-D were allo- or autoantibodies. Serologic D typing and molecular analysis enabled the including of 121 weak D Type 1 individuals and 99 weak D Type 2 individuals in our study. Serologic features of anti-D included autologous controls, direct antiglobulin test, elution, and titration of anti-D before and after adsorption of serum on autologous red blood cells (RBCs). Serologic D typing showed a variable reactivity of RBCs expressing weak D Type 1 or weak D Type 2 (4+ to 0). Anti-D was identified in six weak D Type 1 and six weak D Type 2 individuals, respectively. The serologic data were in favor of autoantibodies. A complete anti-D investigation in individuals with a D variant (weak D or partial D identified by molecular analysis) should be systematically performed before any valid conclusion on the nature of the antibody. Transfusing weak D Type 1 or weak D Type 2 patients with D+ RBC units should be recommended. Weak D Type 1 or weak D Type 2 pregnant women do not need anti-D immunoprophylaxis.

Research paper thumbnail of Relative immunogenicity of Fya and K antigens in a Caucasian population, based on HLA class II restriction analysis

Transfusion, 2006

BACKGROUND: It has long been known that relative immunogenicity is a characteristic of protein re... more 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 Fy a antigen (FY1)-and analyzed the distribution of DRB1* molecules in two groups of Caucasian individuals producing anti-Fy a (n = 29) or anti-K (n = 30) alloantibodies. These experimental results were compared to the results generated by TEPITOPE, a DRB1* peptide-binding motif prediction algorithm. RESULTS: It was found that within the anti-Fy a group, the DRB1*04 phenotypic frequency was 100 percent, indicating that the DRB1*04 molecule is the restriction molecule. In the anti-K group, numerous DRB1* molecules were identified, demonstrating a high degree of histocompatibility promiscuity, corresponding to the predominant molecules in the Caucasian population. These findings were confirmed by TEPITOPE. CONCLUSION: These results strongly suggest that protein RBC intrinsic immunogenicity depends on the distribution of DRB1* restriction molecules.

Research paper thumbnail of Anti-Hr B and anti-hr B revisited

Transfusion, 2009

BACKGROUND: Since their description in the 1970s, anti-Hr B (antibody against a high-prevalence R... more BACKGROUND: Since their description in the 1970s, anti-Hr B (antibody against a high-prevalence Rh antigen) and anti-hr B (anti-e-like antibody) are still a subject of debate about representing two aspects of a global immune response or being two independent antibodies. STUDY DESIGN AND METHODS: The aim of this study was to evaluate the immune response against the antigens of Rh system of 30 individuals presenting a hr B (RH31)-phenotype. Genomic analysis of RH genes was performed in all individuals. RESULTS: Among the 30 individuals, 27 had a Hr B (RH34)-phenotype. No immunization against Rh antigens was found in 16 individuals. Three individuals made anti-D only, whereas six individuals made anti-Hr B (four with anti-hr B and two without anti-hr B ) and two individuals made anti-hr B without anti-Hr B . Among the 30 individuals, three had a Hr B + phenotype. No immunization against Rh antigens was found in one individual, whereas two individuals made anti-hr B ; the genomic analysis of selected individuals showed the presence of a (C)ce s haplotype, either Type 1 or Type 2, and a DIII Type 5 ce s haplotype, in the homozygous state, in compound heterozygosity with each other or in heterozygosity with a DcE haplotype. Genomic data were in accordance with serologic data. CONCLUSION: Our data provide the evidence that anti-Hr B and anti-hr B are independent antibodies, defining two different specificities. These antibodies may be produced by individuals expressing variants of RhCE protein. Serologic and molecular data indicate that e antigen encoded by the (C)ce s haplotype is a partial antigen. In individuals carrying a (C)ce s haplotype, the risk and the type of alloimmunization to Rh antigens are related to the second Rh haplotype.

Research paper thumbnail of Évaluation du portfolio électronique et de son système d’accompagnement dédié à l’évaluation des pratiques professionnelles en technique et médecin e transfusionnelles

Informatique et Santé, 2009

Abstract In order 10 help physicians to meet the compulsory evaluation of professional practices ... more Abstract In order 10 help physicians to meet the compulsory evaluation of professional practices as regards blood transfusion, the French National Blood Transfusion Institute and the University of Nice imagined a structured and accompanied eportfolio available on the Internet, This innovative system, faced up problem of the approval of an implement of new technology intended for a specific professional environment.

Research paper thumbnail of Using a C-Terminal Fragment of C4Binding Protein A Recombinant Human scFv AntiRh(D) Antibody With Multiple Valences

Research paper thumbnail of Flow cytometric evaluation of human basophils

Cytometry, 1993

The expression of CD45 and IgE cell surface antigens on human leucocytes was studied by flow cyto... more The expression of CD45 and IgE cell surface antigens on human leucocytes was studied by flow cytometry. More than 80% of sorted cells that expressed low CD45 (CD45dim) and high IgE (IgEbright) antigen site density were identified as basophils. Immunomagnetic depletion of the CD45dim-IgEbright cell subset by a biotin-coupled anti-IgE antibody and streptavidin-coated magnetic beads was greater than 90%, and more than 80% of cells binding significant numbers of beads exhibited the morphological characteristics of basophils. Interestingly, when the cell staining was performed in the presence of calcium and magnesium, we observed a significant increase of CD45 and an equivalent decrease of IgE cell surface expression, as well as an IgE concentration dependent diminution of the number of CD45dim-IgEbright cells.

Research paper thumbnail of Flow cytometric monitoring of allergen induced basophil activation

Cytometry, 1995

Human basophils express many clustered differentiation antigens (CD), including CD45; however, no... more Human basophils express many clustered differentiation antigens (CD), including CD45; however, none are specific for these cells. In a previous study, we described a two-color immunofluorescence procedure, employing antibodies to CD45 and IgE for the cytometric evaluation of basophils. In the present work, we show that when sensitized basophils are stimulated by allergenic preparations, they demonstrate an upregulation of CD45 as well as a decrease in anti-IgE binding. Since CD45 antigen modulation was observed with all aeroallergens tested and the decrease in IgE expression varied with allergenic preparations, the measurement of CD45 upregulation was used to evaluate basophil activation. Using this approach, reproducible results were observed when atopic patients were tested at different time intervals. In addition, we show that the upregulation of CD45 on allergen stimulated basophils is a very rapid phenomenon that is observed after a few minutes and that this rapid flow cytometr...

Research paper thumbnail of Human monoclonal antibody against Rh(D) antigen: partial characterization of the Rh(D) polypeptide from human erythrocytes

Blood, 1987

A human monoclonal anti-Rh(D) antibody produced by an Epstein-Barr virus (EBV)-transformed B-cell... more A human monoclonal anti-Rh(D) antibody produced by an Epstein-Barr virus (EBV)-transformed B-cell line (IgG1(lambda), clone H2D5D2) has been purified on protein A-Sepharose column and used for binding studies and immune precipitation of the blood group rhesus (Rh) antigens. Scatchard plot analyses show that the 125I-labeled antibody (iodo-gen procedure), binds to 1.09 X 10(5), 0.43 X 10(5), and 0.32 X 10(5) antigen sites on each D--/D--, R2R2 and R1R1 RBC, respectively, with an association constant of approximately 0.6 X 10(8) mol/L-1. Immune precipitation studies indicate also that the Rh(D) antigen of the Rh(D)-positive RBCs is carried by a 29 kd polypeptide as deduced from sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). No material could be precipitated from Rh(D)-negative or Rhnull RBCs. These results indicate that the monoclonal and the polyclonal human anti-Rh(D) behave similarly. A sample (Blo., presumed genotype R2r or R0R2) showing an increased number ...

Research paper thumbnail of « Lecture critique appliquée au vieillissement » L.-R. Salmi, M. Rainfray, J.-F. Dartigues. Éditions Elsevier

Research paper thumbnail of UN EPORTFOLIO STRUCTURÉ ET TUTORÉ POUR LA GESTION ET LE SUIVI PERSONNALISÉ DE L’EVALUATION DES PRATIQUES PROFESSIONNELLES EN TECHNOLOGIE ET MÉDECINE TRANSFUSIONNELLES

Research paper thumbnail of Professeur Jacques Ruffié (1921–2004)

Transfusion Clinique et Biologique, 2004

Research paper thumbnail of Fatal hemolytic disease of the fetus and newborn associated with anti-Jr a

Research paper thumbnail of Heterogeneous molecular background of the weak C, VS+, hr B -, Hr B - phenotype in black persons

Transfusion, 2009

The rare Hr B -phenotype is encoded by the (C)ce s haplotype when present at the homozygous state... more The rare Hr B -phenotype is encoded by the (C)ce s haplotype when present at the homozygous state. This haplotype contains two altered genes: a hybrid RHD-CE-D s gene segregated with a ce s allele of RHCE (733C>G and 1006G>T substitutions in Exon 5 and Exon 7 respectively). The aim of this study was to further investigate the molecular background of the (C)ce s haplotype. STUDY DESIGN AND METHODS: Twelve individuals with depressed C and/or depressed e phenotype were selected from their genomic DNA analysis showing both 733C>G and 1006G>T substitutions. Phenotypic expression of low-and high-prevalence Rh antigens was studied. Complete sequences of RHD and RHCE transcripts were analyzed when obtained.

Research paper thumbnail of Alloanti-c (RH4) revealing that the (C)ce s haplotype encodes a partial c antigen

Research paper thumbnail of Alloanti-c/ce in a c+ ceAR/Ce patient suggests that the rare RHCE*ceAR allele ( ceAR ) encodes a partial c antigen

Research paper thumbnail of Blood group genotyping by high-throughput DNA analysis applied to 356 reagent red blood cell samples

Transfusion, 2011

BACKGROUND: DNA analysis for the prediction of blood group antigen expression has broad implicati... more BACKGROUND: DNA analysis for the prediction of blood group antigen expression has broad implications in transfusion medicine. It may be of particular interest especially to detect variants, when antigen expression is weak or altered. The use of high-throughput DNA analysis has never been applied to donors whose red blood cells (RBCs) are selected for reagent RBCs. The aim of this study was to analyze the concordance between the serologic phenotype and that predicted from DNA analysis in panel donors, to determine the benefit of the use of DNA analysis in reagent RBC selection strategy.

Research paper thumbnail of HIV antibody screening remains indispensable for ensuring viral safety of blood components despite NAT implementation

Transfusion, 2003

The main objective of the implementation of NAT for the screening of blood-borne viruses was to c... more The main objective of the implementation of NAT for the screening of blood-borne viruses was to compensate for the failure of serologic assays during the window period. Because this new screening procedure theoretically covers the entire period of infectivity, the necessity for maintaining serologic assays in blood screening strategy could become questionable. To investigate this issue, a panel of 35 samples has been studied by NAT. These samples had been collected from HIV-1 antibody-positive individuals presenting a persistently low viral RNA load (<400 copies/mL) in the absence of antiviral therapy. All samples were analyzed with the minipool (x8) NAT routinely used in blood bank setting (HIV-1 and HCV assay based on transcription-mediated amplification) and with single-donation testing. The minipool NAT failed to detect the presence of HIV RNA in 15 of the 35 samples (11 remained negative when retested). Single-donation testing gave negative results in 4 samples (3 remained negative when retested). Fourteen of the 18 samples with a viral load greater than 50 copies per mL were positive by minipool NAT versus 6 of the 17 samples with fewer than 50 copies per mL (p = 0.02). The results clearly demonstrate that anti-HIV screening should not be withdrawn from biologic qualification procedures of blood donations, even when single NAT is performed.

Research paper thumbnail of Molecular background of D(C)(e) haplotypes within the white population

Transfusion, 2002

BACKGROUND: D(C)(e) and D(C)e haplotypes may be encountered in the white population. Few data are... more BACKGROUND: D(C)(e) and D(C)e haplotypes may be encountered in the white population. Few data are available on the molecular backgrounds responsible for depressed expression of C and e. STUDY DESIGN AND METHODS: Individuals of white origin carrying a D(C)(e) genotype resulting in depressed expression of C or both C and e were subdivided into two categories based on the RBC reactivity with the human sera Mol and Hor, which contain antibodies against low-frequency antigens of the Rh (RH) system and other non-Rh low-frequency antigens. Neither Hor+, Mol+ nor Hor+, Mol-RBCs expressed the V (RH10), VS (RH20), and/or Rh32 (RH32) low-frequency antigens. These results suggested that Hor+, Mol+ variants expressed Rh33 (RH33 or Har) and FPTT (RH50), whereas Hor+, Mol-variants might express an undefined low-frequency antigen. Further serologic and molecular analyses were performed. RESULTS: Molecular analysis of Hor+, Mol+ variants revealed a hybrid gene structure RHCe-D(5)-Ce, in which exon 5 of RHCE (RHCe allele) was replaced by exon 5 of RHD (the so-called RHCeVA allele). The presence of exon 5RHD resulted in several amino acid alterations predicted in the external loop 4 of the CeVA polypeptide. Molecular analysis of Hor+, Mol-variants revealed the presence of a new RHCe allele characterized by a single point mutation C340T within exon 3 (the so-called RHCeMA allele), resulting in a R114W substitution predicted on the external loop 2 of the CeMA polypeptide. A serologic study showed a different pattern of reactivity with C and e MoAbs. CONCLUSION: Two types of mutations resulted in amino acid substitutions predicted in external loops 4 and 2, respectively, which altered both the C and e reactivity, and indicated conformation changes or defective interaction between nonadjacent loops of the Ce polypeptide. Serologic analysis showed that together with Hor and Mol sera testing, the use of different C and e MoAbs could help to identify these variants within the white population. ABBREVIATION: SSP = sequence-specific primer.

Research paper thumbnail of Analysis of complement receptor Type 1 expression on red blood cells in negative phenotypes of the Knops blood group system, according to CR1 gene allotype polymorphisms

Transfusion, 2010

The KN blood group system, which consists of nine antigen specificities, is located on complement... more The KN blood group system, which consists of nine antigen specificities, is located on complement receptor Type 1 (CR1/CD35). CR1, a complement regulatory protein, acts as a vehicle for immune complex clearance. CR1 exhibits a red blood cell (RBC) density polymorphism. CR1 sites on RBCs in normal individuals range from 150 to 1200 molecules per cell. CR1 density polymorphism is regulated by HindIII restriction fragment length polymorphism and Q981H and P1786R polymorphisms in Caucasians. Yet, the role of the different polymorphisms in determining the CR1 density on RBCs remains unknown. The "null" serologic KN phenotype, known as Helgeson phenotype, was reported to be related with a very low CR1 density, less than 150 molecules per cell.

Research paper thumbnail of Anti-U-like as an alloantibody in S−s−U− and S−s−U+var black people

Research paper thumbnail of Anti-D investigations in individuals expressing weak D Type 1 or weak D Type 2: allo- or autoantibodies?

Transfusion, 2011

Whether anti-D produced by individuals with a weak D phenotype are allo- or autoantibodies remain... more Whether anti-D produced by individuals with a weak D phenotype are allo- or autoantibodies remains a matter of debate even though blood transfusion practice is impacted. The aim of our study was to determine the serologic features of anti-D in individuals expressing the most frequent weak D type in Caucasians that are weak D Type 1 or weak D Type 2, to assess whether anti-D were allo- or autoantibodies. Serologic D typing and molecular analysis enabled the including of 121 weak D Type 1 individuals and 99 weak D Type 2 individuals in our study. Serologic features of anti-D included autologous controls, direct antiglobulin test, elution, and titration of anti-D before and after adsorption of serum on autologous red blood cells (RBCs). Serologic D typing showed a variable reactivity of RBCs expressing weak D Type 1 or weak D Type 2 (4+ to 0). Anti-D was identified in six weak D Type 1 and six weak D Type 2 individuals, respectively. The serologic data were in favor of autoantibodies. A complete anti-D investigation in individuals with a D variant (weak D or partial D identified by molecular analysis) should be systematically performed before any valid conclusion on the nature of the antibody. Transfusing weak D Type 1 or weak D Type 2 patients with D+ RBC units should be recommended. Weak D Type 1 or weak D Type 2 pregnant women do not need anti-D immunoprophylaxis.

Research paper thumbnail of Relative immunogenicity of Fya and K antigens in a Caucasian population, based on HLA class II restriction analysis

Transfusion, 2006

BACKGROUND: It has long been known that relative immunogenicity is a characteristic of protein re... more 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 Fy a antigen (FY1)-and analyzed the distribution of DRB1* molecules in two groups of Caucasian individuals producing anti-Fy a (n = 29) or anti-K (n = 30) alloantibodies. These experimental results were compared to the results generated by TEPITOPE, a DRB1* peptide-binding motif prediction algorithm. RESULTS: It was found that within the anti-Fy a group, the DRB1*04 phenotypic frequency was 100 percent, indicating that the DRB1*04 molecule is the restriction molecule. In the anti-K group, numerous DRB1* molecules were identified, demonstrating a high degree of histocompatibility promiscuity, corresponding to the predominant molecules in the Caucasian population. These findings were confirmed by TEPITOPE. CONCLUSION: These results strongly suggest that protein RBC intrinsic immunogenicity depends on the distribution of DRB1* restriction molecules.

Research paper thumbnail of Anti-Hr B and anti-hr B revisited

Transfusion, 2009

BACKGROUND: Since their description in the 1970s, anti-Hr B (antibody against a high-prevalence R... more BACKGROUND: Since their description in the 1970s, anti-Hr B (antibody against a high-prevalence Rh antigen) and anti-hr B (anti-e-like antibody) are still a subject of debate about representing two aspects of a global immune response or being two independent antibodies. STUDY DESIGN AND METHODS: The aim of this study was to evaluate the immune response against the antigens of Rh system of 30 individuals presenting a hr B (RH31)-phenotype. Genomic analysis of RH genes was performed in all individuals. RESULTS: Among the 30 individuals, 27 had a Hr B (RH34)-phenotype. No immunization against Rh antigens was found in 16 individuals. Three individuals made anti-D only, whereas six individuals made anti-Hr B (four with anti-hr B and two without anti-hr B ) and two individuals made anti-hr B without anti-Hr B . Among the 30 individuals, three had a Hr B + phenotype. No immunization against Rh antigens was found in one individual, whereas two individuals made anti-hr B ; the genomic analysis of selected individuals showed the presence of a (C)ce s haplotype, either Type 1 or Type 2, and a DIII Type 5 ce s haplotype, in the homozygous state, in compound heterozygosity with each other or in heterozygosity with a DcE haplotype. Genomic data were in accordance with serologic data. CONCLUSION: Our data provide the evidence that anti-Hr B and anti-hr B are independent antibodies, defining two different specificities. These antibodies may be produced by individuals expressing variants of RhCE protein. Serologic and molecular data indicate that e antigen encoded by the (C)ce s haplotype is a partial antigen. In individuals carrying a (C)ce s haplotype, the risk and the type of alloimmunization to Rh antigens are related to the second Rh haplotype.