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Publications (4)13.72 Total impact

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    ABSTRACT: Multiparametric flow cytometry has proven to be a powerful method for detection and immunophenotypic characterization of clonal subsets, particularly in lymphoproliferative disorders of the B-cell lineage. Although in theory promising, this approach has not been comparably fulfilled in mature T-cell malignancies. Specifically, the T-cell receptor-Vβ repertoire analysis in blood can provide strong evidence of clonality, particularly when a single expanded Vß family is detected. The purpose of this study was to determine the relevance of this approach when applied to biopsies, at the site of tumor involvement. To this end, 30 peripheral T-cell lymphoma and 94 control biopsies were prospectively studied. Vβ expansions were commonly detected within CD4+ or CD8+ T cells (97% of peripheral T-cell lymphoma and 54% of non-peripheral T-cell lymphoma cases); thus, not differentiating malignant from reactive processes. Interestingly, we demonstrated that using a standardized evaluation, the detection of a high Vβ expansion was closely associated with diagnosis of peripheral T-cell lymphoma, with remarkable specificity (98%) and sensitivity (90%). This approach also identified eight cases of peripheral T-cell lymphoma that were not detectable by other forms of immunophenotyping. Moreover, focusing Vβ expression analysis to T-cell subsets with aberrant immunophenotypes, we demonstrated that the T-cell clone might be heterogeneous with regard to surface CD7 or CD10 expression (4/11 cases), providing indication on 'phenotypic plasticity'. Finally, among the wide variety of Vβ families, the occurrence of a Vβ17 expansion in five cases was striking. To our knowledge, this is the first report demonstrating the power of T-cell receptor-Vβ repertoire analysis by flow cytometry in biopsies as a basis for peripheral T-cell lymphoma diagnosis and precise T-cell clone identification and characterization.
    Modern Pathology 05/2012; 25(9):1246-57. · 5.25 Impact Factor
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    ABSTRACT: After HLA-identical hematopoietic stem cell transplantation, minor histocompatibility (mH) antigen alloreactivity plays a dominant role in the development of graft-versus-host disease (GVHD) and graft versus leukemia (GVL). We have analyzed the mH alloreactivity (enzyme-linked immunospot [ELISpot] for interferon-gamma[IFN-gamma] assay) from 24 donor/recipient pairs over a period of 2 years of follow-up and correlated such alloreactivity with the development of GVHD or absence of relapse. Circulating specific T cells anti-mH with multimer HLA-peptides were also studied. We show by ELISpot IFN-gamma assay that alloreactivity during the first 3 months from donor versus recipient or donor versus mismatched identified mH antigens is associated with acute GVHD and GVL effect. In addition, we demonstrate that the donor-versus-recipient reactivity observed after the third month is highly associated with chronic GVHD and GVL (p = 0.0007). Finally, we show by multimer HLA-peptide assay that mH epitope-specific T cells present after 3 months are statistically related to the GVL effect. Our results provide a robust method to monitor mH antigen graft-versus-host reaction and suggest that current identified mH have predictive value on GVHD and GVL.
    Transfusion 10/2009; 50(2):418-28. · 3.53 Impact Factor
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    ABSTRACT: Analysis of the T-cell receptor (TCR) repertoire by flow cytometry proved to be relevant for investigating T-cell diversity and detecting reactive cells in blood samples. We used this approach to characterize non-malignant T-lymphocytes in lymph nodes and give insights into their origin. The TCR repertoire of CD4+ and CD8+ T-cells from 81 lymph nodes was analyzed with a four-color flow cytometer using a wide panel of 25 anti-Vbeta monoclonal antibodies. Flow cytometry proved to be a useful and informative technique. We demonstrated a diversified TCR-Vbeta repertoire, and only low level expansions, in 53% of the samples. They involved nearly all Vbeta families, were more frequent in the CD8+ subset of older patients, but were not related to pathology. No evidence could be demonstrated in favor of stimulation by common antigens. Interestingly, the TCR-Vbeta repertoire proved to be very similar in lymph nodes and blood samples. Our results argue that in the cases studied, lymph node enlargement is mainly due to an increased homing of circulating T-cells. They also provide reference values for expression of 25 TCR-Vbeta in lymph nodes, which could serve as a basis for further applications in diagnosis of T-cell lymphoproliferative disorders.
    Cytometry Part A 08/2009; 75(9):743-51. · 3.71 Impact Factor
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    ABSTRACT: In agreement with good practices for therapeutic use of human cells, quality control has to be performed to valid the process of extracorporeal photopheresis (ECP) with the Vilbert-Lourmat system. Since no protocol exists, we evaluated a technique based on the measurement of the inhibition of mitogen (PHA, Con-A, OKT3)-induced proliferation, in 164 procedures from 16 patients. Whatever the pathology, we observed a high proliferation rate in most samples, and we obtained over 90% ECP-induced inhibition in as many as 94% of the cases. Since this approach proved to be relevant regarding our objective, a protocol for the ECP process validation is proposed.
    Transfusion and Apheresis Science 03/2003; 28(1):63-70. · 1.23 Impact Factor