Biomedical subjects

Y Mérieux

Publications and source records attributed to Y Mérieux.

6 recordsLinked to original sources

PubMed2005

New method for DNA microarrays development: applied to human platelet antigens polymorphisms.

DNA microarrays are a powerful experimental tool for the detection of specific genomic sequences and are invaluable to a broad array of applications: clinical diagnosis, personalized medicine, drug research and development, gene therapy, food control technologies, and environmental sciences. Alloimmunization to human platelet antigens (HPAs) is commonly responsible for neonatal alloimmune thrombocytopenia, post-transfusional purpura and platelet transfusion refractoriness. Using DNA microarrays, we developed a diagnosis to type the biallelic HPA-1 platelet group. The region for the human genomic DNA sequence that contains the polymorphism responsible for HPA-1 alleles was amplified by polymerase chain reaction (PCR). The expected DNA fragments were hybridized on DNA microarrays, and the data were analyzed using specially developed software. Our initial results show that the two HPA-1 antigens polymorphisms containing a single base difference were detected using DNA microarrays.

Antigens, Human Platelet↗

PubMed2004

HLA antibodies and neonatal alloimmune thrombocytopenia.

A female baby with a severe thrombocytopenia at 18 x 10(9)/l was born to a 29-year-old (gestation 2/partum 2) mother. Scattered petechiae were present on her legs, arms, chest and face, but there was no bleeding, infection, fever or hepatosplenomegaly. A platelet antibody screening immunocapture test was positive, which was performed on the mother's serum 3, 12 and 38 days after delivery, but no platelet-specific antibodies were found by the monoclonal-antibody-specific immobilization of platelet antigen assay. The baby's platelets and lymphocytes and the father's platelets reacted strongly with the HLA antibodies present in the mother's serum. The neonate was treated with intravenous human immunoglobulin (Tegeline), 1 g/kg per day) 1, 2 and 3 days after delivery. The platelet count rose from 18 x 10(9)/l on day 0 to 37 x 10(9)/l on day 3 and to 227 x 10(9)/l on day 12. No platelet transfusion was needed. Several factors which developed hereafter lead us to think that this neonatal alloimmune thrombocytopenia is due to the transplacental passage of maternal HLA antibodies to the baby.

Adult↗

PubMed1997

Human platelet antigen frequencies of platelet donors in the French population determined by polymerase chain reaction with sequence-specific primers.

To prevent human platelet alloimmunization, Blood Transfusion Centres have to develop a strategy close to the erythrocytes' one. The first step of this strategy is to perform the HPA typing of donors with an accurate method. We applied the PCR-SSP to type 800 platelet donors in the HPA-1 and HPA-5 systems and 350 in the HPA-2 and HPA-3 ones. This study reports the human platelet antigen frequencies of four platelet-specific alloantigen systems in the French population. The results are quite similar to those currently published for Caucasian population frequencies. Low prevalences are observed for the HPA-1b, (2%), HPA-2b (0.6%) and HPA-5b (2%) groups. Furthermore, this study confirms the need to type donors and recipients in the HPA-1 system at least, in case of post-transfusion pupura and platelet refractoriness to platelet transfusion therapy.

Antigens, Human Platelet↗

PubMed1997

[Contribution of dual CD13/CD14 markers in combination with CD34 for the collection of peripheral hematopoietic stem cells].

We evaluated the reliability of a flow cytometry technique for counting mononuclear cells (MNCs) in cytapheresis products. Eighty freshly-prepared samples of peripheral stem cells were studied using a dual immunolabeling technique with antibodies to CD13/CD14, and were also labeled with anti-CD34. Results of this immunophenotype determination were compared to those of the conventional method for counting MNCs under the microscope. Dual CD13/CD14 labeling was found to be a simple and reliable method for counting MNCs in the presence of immature and stimulated cells. When used in combination with CD34 labeling, the dual immunolabeling method helped improve the evaluation of the quality of peripheral stem cell grafts.

Antigens, CD34↗

PubMed1996

Expression of a NK cell-restricted epitope on decidual large granular lymphocytes.

Decidual large granular lymphocytes (DLGL) are the most abundant lymphoid cell type found in the first trimester maternal decidua. The function of DLGL remains controversial, although freshly isolated DLGL have been shown to exert a weak NK activity. We report here the phenotypic characterization of two DLGL subpopulations by immunofluorescence, using mAb against CD56, PEN5 as well as adhesion molecules potentially involved in cell-cell contact between DLGL and trophoblasts. DLGL are CD56bright and express the CD2, CD11a, CD18, CD38 and CD50 molecules, dimly the CD54 molecule, and poorly the CD102 and CD69 molecules. A strong expression of the polysialylated form of N-CAM (or CD56) was also observed on the surface of DLGL. Finally, 40% of CD56bright DLGL cells express the PEN5 epitope, which is selectively expressed on CD56dim cells NK in the peripheral blood. No other phenotypic difference was detected between the CD56brightPEN5+ and the CD56brightPEN5- DLGL populations. Our results show that DLGL are heterogeneous and suggest that the CD56brightPEN5+ DLGL subset belongs to the classical NK cell lineage.

Amino Sugars↗

PubMed1996

Strong increase in the percentage of the CD8bright+ CD28- T-cells and delayed engraftment associated with cyclosporine-induced autologous GVHD.

Four children with acute lymphoblastic leukaemia had autologous bone marrow (BM) or peripheral stem cell (PSC) transplantation with low dose of cyclosporine (CsA, img/kg/d i.v. during the first 28 d) to induce an autologous GVHD (auto-GVHD). Two children did not have clinical auto-GVHD and they relapsed 3 and 4 months after treatment. The 2 other children had clinical signs of auto-GVHD (grade I and grade II); they both are in complete remission but after a first normal haematological recovery they had a prolonged period of aplasia until month 9 for 1 patient and still persistent at month 7 in the other case. We studied lymphocyte subsets reconstitution after transplantation in these patients. All patients had an important decrease in the CD4/CD8 ratio related both to a strong decrease in the CD4+ cells and a strong increase in the CD8+ cells. Most of the CD8+ cells were of the CD8bright+ CD28- phenotype. These CD8bright+ CD28- T-cells represented from 33% to 68% of the total lymphocytes. We discuss the role of these cells after autologous transplantation with CsA, and wonder if these cells could mediate cytotoxicity. In conclusion, among 4 children who received autologous BM or PBC transplantation with low dose of CsA, we observed a complete remission after an auto-GVHD and a prolonged period of aplasia in 2 patients and a relapse of leukaemia in 2 other patients. All these 4 patients had an increase in the CD8bright+ CD28- T lymphocytes.

Autoimmune Diseases↗