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P Rouger

Publications and source records attributed to P Rouger.

At least 73 records · Page 4Linked to original sources
PubMed1998

An enzyme-linked immunosorbent assay for the quantitation of IgG anti-D and IgG subclasses in the sera of alloimmunized patients.

BACKGROUND: IgG subclass composition of maternal alloantibodies to the D antigen seems to play a role in the severity of hemolytic disease of the newborn. The subclassing of IgG anti-D is usually performed by hemagglutination techniques, but the results are not quantitative and sometimes are difficult to interpret. Thus, there is a need for quantitative methods. STUDY DESIGN AND METHODS: The aim of this study was to develop an enzyme-linked immunosorbent assay (ELISA) for the quantitation of specific IgG anti-D and IgG subclasses in the sera of alloimmunized patients. Group O R1R2 red cells were sensitized with anti-D. Red cell membranes were solubilized with nonionic detergent. IgG and IgG subclasses were measured by a sensitive and reproducible immunocapture ELISA. A serum calibrated for its IgG subclass content was used as a reference, and the anti-D preparation 68/419 was used as an internal control. Optimal conditions for the detection of IgG anti-D and IgG subclasses by ELISA were studied. The absolute concentration and the proportions of IgG subclasses were determined in the sera of 14 pregnant women. RESULTS: A close parallelism was observed between dilutions of the IgG reference serum and the IgG anti-D solubilized from sensitized RBCs. The sum of IgG anti-D subclass concentrations, determined by the ELISA, correlated well with other quantitative methods. CONCLUSION: The method described is sensitive and can be used routinely for the quantitative determination of specific IgG anti-D and IgG subclasses in sera.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

A recombinant human scFv anti-Rh(D) antibody with multiple valences using a C-terminal fragment of C4-binding protein.

Monomeric recombinant molecules prove generally unsatisfactory for in vivo use. Most biological systems are indeed multivalent either structurally, associating different chains, or functionally, when cross-linked by their ligands. Mimicking natural molecules for immune intervention implies the need for multimerizing systems to create multivalent molecules capable of interfering with physiological processing. A multivalent anti-Rh(D) recombinant protein has been designed by reconstructing the antibody binding site of a human monoclonal anti-Rh(D) antibody as a single chain Fv mini antibody, then multimerizing it by inserting at its C-terminal end the C-terminal part of the C4 binding protein (C4bp) alpha chain, which is responsible for the octamer multimerization of that molecule. This soluble multivalent recombinant molecule was functional, bound red blood cells (RBCs), agglutinated them, and did not activate complement. This demonstration model opens the way for future in vivo use of multivalent molecules associating antibody valences and other functional molecules for cell targeting, imaging, or removal of cells such as Rh(D)-positive RBCs for preventing Rh alloimmunization.

Amino Acid Sequence↗
PubMed1997

Advances in the use of monoclonal antibodies for blood group testing.

Until the '80s blood group reagents were composed of human or animal polyclonal antibodies; nowadays they are mainly produced from monoclonal antibodies. In this paper two aspects will be considered; firstly the evolution in the use of monoclonal reagents in France and secondly the quality of these new reagents in comparison with polyclonal reagents. From 1981 to 1995, 17567 batches of blood group reagents were analyzed and controlled by the French Blood Group Reference Laboratory (CNRGS). All data are given in six tables.

ABO Blood-Group System↗
PubMed1996

Characterization of the gene encoding the human LW blood group protein in LW+ and LW- phenotypes.

The LW blood group is carried by a 42-kD glycoprotein that belongs to the family of intercellular adhesion molecules. The LW gene is organized into three exons spanning an HindIII fragment of approximately 2.65 kb. The exon/intron architecture correlates to the structural domains of the protein and resembles that of other Ig superfamily members except that the signal peptide and the first Ig-like domain are encoded by the first exon. The 5'UT region (nucleotides -289 to +9) includes potential binding sites for various transcription factors (Ets, CACC, SP1, GATA-1, AP2) and exhibited a significant transcriptional activity after transfection in the erythroleukemic K562 cells. No obvious abnormality of the LW gene, including the 5'UT region, has been detected by sequencing polymerase chain reaction-amplified genomic DNA from RhD+ or RhD- donors and from an Rhnull variant that lacks the Rh and LW proteins on red blood cells. However, a deletion of 10 bp in exon 1 of the LW gene was identified in the genome of an LW (a- b-) individual (Big) deficient for LW antigens but carrying a normal Rh phenotype. The 10-bp deletion generates a premature stop codon and encodes a truncated protein without transmembrane and cytoplasmic domain. No detectable abnormality of the LW gene or transcript could be detected in another LW(a- b-) individual (Nic), suggesting the heterogeneity of these phenotypes.

Amino Acid Sequence↗
PubMed1996

[The direct antiglobulin and elution tests: evaluation of quality control in Blood Transfusion Centers].

The Société Française de Transfusion Sanguine and the Centre National de Référence pour les Groupes Sanguins performed a quality control to evaluate the performances of two serological tests: the Direct Antiglobulin Test (DAT) and the Elution test. Among the 110 Blood Transfusion Centers participating in this control, 80 (73%) returned a result. Of these, 68 results were correct for the DAT (85%; positive for type IgG) and 31 results were correct for the elution (39%; anti-FY1). This control gave the opportunity to confirm the main procedures used in routine testing on a national scale. The analysis of the results underlines the importance of the choice of a standardized technique for these tests. Such controls are useful to appreciate the quality of the routine tests and to find the means to improve them.

Blood Transfusion↗
PubMed1996

[Quality assurance and prevention of immuno-hemolytic incidents in blood transfusion].

Direct and indirect measures of the reliability of the transfusion process are described. These measures can be used to assess the improvement of the transfusion process with a view to preventing hemolytic incidents. Quality assurance arrangements required by their use are made clear. The stress is put upon four points: processes must be formalized and standardised; quality audits must become a routine part of the transfusion process; the system of error reporting must be extended to include all failures; anonymity must be insured to improve reporting.

Anemia, Hemolytic↗
PubMed1996

[DNA polymorphism and paternity exclusions: analysis of 543 cases of paternity testing].

The study of the genetic markers of polymorphism has known a very large evolution during these last ten years in relation to the development of the molecular biology and the discovery and analysis of some DNA repeated loci. In a study of 543 of paternity testing, the authors analyse the performance of some probes, the limits of their using, the program and strategy of testing to establish a high probability of exclusion.

DNA↗
PubMed1996

[Improvement of transfusion safety in a health care service through the implementation of a quality program].

The quality policy brings with it an efficient method as well as relevant tools to improve transfusion safety in health care services. This article illustrates the details of the approach through the presentation of a project developed in the East Picardie region throughout several hospitals. It underlines the importance of the choice of a good reference system, of a pertinent method and the necessity of a real project management. Furthermore, the follow-up of the project has enabled us to identify a certain number of success criteria in the steering of the changing process.

France↗
PubMed1996

[Immuno-hemolytic transfusion accidents. I. General remarks].

The transfusion of red blood cells may induce an immediate immunological risk and prompt reactions of the immune system, causing the production of alloantibodies. Therefore, it is presently vital to assess the benefit-risk ratio of treatment, to be fully aware of the reality of risk and to prevent immunological complications and reactions.

Clinical Trials as Topic↗
PubMed1996

[Immuno-hemolytic transfusion reactions. II Physiopathologic basis and diagnosis].

Immunological transfusion reactions more than often lead to an activation of the complement proteins and mononuclear cells, inducing a haemolysis from which stem the observed clinical symptoms. In the case of incompatibility, the alloantibodies can lead to an immediate reaction, taking place in the first few minutes or, in the case of a delayed reaction, arising after 24 hours. A standardized clinical and biological evaluation is necessary in order to confirm the diagnosis and to assess the consequences of the antigen-antibody conflict.

Diagnosis, Differential↗
PubMed1996

[Immuno-hemolytic transfusion reactions. III. Report of 61 cases].

Blood transfusion is mainly bound to immunological and infectious risks. The immunological risk originates from an incompatibility between the blood of the donor and that of the recipient; this risk remains insufficiently assessed. A multicentre study has been carried out by the French Blood Transfusion Society and the National Institute for Blood Transfusion. Sixty-one accidents due to an erythrocyte incompatibility were found: 26 cases with ABO incompatibility, and 35 cases with alloantibodies of other blood group systems. For the former category of accidents, the most frequent cause was due to a failure in the realization of the bedside ABO check. For the latter, the main problem was the achievement and the interpretation of antibody screening. The long term follow-up shows no chronic after-effects of immunological accidents. For each accident, errors have been identified and analysed. It was proven that they all originate from health care establishments.

ABO Blood-Group System↗
PubMed1996

[Immuno-hemolytic transfusion reactions. IV. Analysis, risks and prevention].

The immunological risk of red blood cell transfusions now seems higher than the viral risk. According to studies, severe accidents due to blood incompatibility occur with a frequency estimated at 1/6000 to 1/29000; despite technical progress, the risk does not significantly diminish. The majority of accidents do not originate from laboratory or production stages but from defects in the application of clinical procedures. Preventive measures are based on (i) the elaboration of clinical guidelines, (ii) the compliance to strict rules in carrying out bedside ABO check, and (iii) the realization and interpretation of antibody screening tests. The implementation of quality assurance systems and of the epidemiological surveillance system, which define the basis of a prevention policy, leads to the expectation of an improvement of transfusion safety.

Adult↗
PubMed1996

Serological studies of monoclonal RH1(D) antibodies with RH1(D) variants.

In this paper we chose to emphasize three aspects of our work. First we underlined that "low grade and high grade" D weak red blood cells studied at the DNA level could, when monoclonal antibodies were used, give patterns of positive and negative reactions like partial RH1(D) cells. Secondly, we showed the importance of the technical conditions of the study which are essential for establishing a pattern of reactivity defining an epitope. It appears that the use of papain treated cells at room temperature can be misleading for the definition of epitope especially with IgM antibodies. Lastly we pointed out the interest of Rh variant cells, defined at the gene level, to study the expression of RH1(D) epitopes on the external part of the membrane.

Antibodies, Monoclonal↗
PubMed1996

Flow cytometric evaluation of non anti-RH1(D) monoclonal Rh antibodies.

IgG non anti-RH1(D) monoclonal Rh antibodies were evaluated by flow cytometry. The values obtained with these antibodies were less strong than those obtained with anti-RH1(D) antibodies. For a significant number of antibodies, the signal was not high enough to give reliable results for the antibody specificity. Despite these drawbacks, flow cytometry was an efficient tool to appreciate the variation of reactivity by different antibodies with normal or variant cells. These variations were not always obvious by serological means.

Animals↗