Laboratory of Immunology and Immunotherapy

Baguer-Morvan, France

Laboratory of Immunology and Immunotherapy

Baguer-Morvan, France
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Tempescul A.,Institute of Oncology and Haematology | Tempescul A.,French Institute of Health and Medical Research | Bagacean C.,French Institute of Health and Medical Research | Riou C.,Institute of Oncology and Haematology | And 11 more authors.
European Journal of Haematology | Year: 2016

The management of patients with chronic lymphocytic leukaemia (CLL) has improved with the utilisation of ofatumumab as a novel anti-CD20 monoclonal antibody. However, as half of the patients fail to respond to the treatment, the aim of this study was to evaluate circulating CLL cell depletion and clinical response according to the context of complement activation and FcγRIIIA polymorphism in ten CLL patients with relapsed/refractory disease. At the end of the treatment, results indicated that circulating CD5+ CD19+ CLL cell depletion was major (<0.01 × 109/L) in 4 of 10 patients, partial (>50% decrease) in 4 of 10 patients and ineffective for the two other patients. No clinical modifications were observed following ofatumumab introduction. Ofatumumab administration leads to a rapid and important exhaustion of complement C4 levels in patients with initial lymphocytosis. C4 exhaustion was accelerated in a non-responder patient, and incomplete in two patients with partial circulating depletion. Moreover, delaying weekly to monthly ofatumumab injections improved CLL cell depletion in two patients. FcγRIIIA 158 polymorphism (FF n = 6 and VF n = 4) was not associated with major and/or partial circulating CLL cell depletion. In conclusion, ofatumumab induces an important C4 exhaustion that needs to be taken into account when treating CLL patients with ofatumumab. © 2016 John Wiley & Sons A/S.

Guerrier T.,iGo | Pochard P.,iGo | Lahiri A.,iGo | Youinou P.,iGo | And 5 more authors.
Journal of Autoimmunity | Year: 2014

Toll-like receptors (TLRs) are positioned at the interface between innate and adaptive immunity. Unlike others, those such as TLR9, that recognize nucleic acids, are confined to the endosomal compartment and are scarce on the cell surface. Here, we present evidence for TLR9 expression on the plasma membrane of B cells. In contrast to endosomal TLR9, cell surface TLR9 does not bind CpG-B oligodeoxynucleotides. After B cell-receptor (BCR) stimulation, TLR9 was translocated into lipid rafts with the BCR, suggesting that it could serve as a co-receptor for BCR. Nevertheless, stimulation of B cells with anti-TLR9 antibodies did not modify the BCR-induced responses despite up-regulation of tyrosine phosphorylation of proteins. However, CpG-B activation of B cells, acting synergistically with BCR signals, was inhibited by anti-TLR9 stimulation. Induction of CD25 expression and proliferation of B cells were thus down-regulated by the engagement of cell surface TLR9. Overall, our results indicate that TLR9 expressed on the plasma membrane of B cells might be a negative regulator of endosomal TLR9, and could provide a novel control by which activation of autoreactive B cells is restrained. © 2014 Elsevier Ltd.

Le Dantec C.,European University of Brittany | Vallet S.,University of Western Brittany | Brooks W.H.,University of South Florida | Renaudineau Y.,European University of Brittany | Renaudineau Y.,Laboratory of Immunology and Immunotherapy
Viruses | Year: 2015

Human endogenous retrovirus group E (HERV-E) elements are stably integrated into the human genome, transmitted vertically in a Mendelian manner, and are endowed with transcriptional activity as alternative promoters or enhancers. Such effects are under the control of the proviral long terminal repeats (LTR) that are organized into three HERV-E phylogenetic subgroups, namely LTR2, LTR2B, and LTR2C. Moreover, HERV-E expression is tissue-specific, and silenced by epigenetic constraints that may be disrupted in cancer, autoimmunity, and human placentation. Interest in HERV-E with regard to these conditions has been stimulated further by concerns regarding the capacity of HERV-E elements to modify the expression of neighboring genes and/or to produce retroviral proteins, including immunosuppressive env peptides, which in turn may induce (auto)-antibody (Ab) production. Finally, better understanding of HERV-E elements may have clinical applications for prevention, diagnosis, prognosis, and therapy. © 2015 by the authors; licensee MDPI, Basel, Switzerland.

Brooks W.H.,University of South Florida | Renaudineau Y.,European University of Brittany | Renaudineau Y.,Laboratory of Immunology and Immunotherapy
Frontiers in Genetics | Year: 2015

Autoimmune diseases occur more often in females, suggesting a key role for the X chromosome. X chromosome inactivation, a major epigenetic feature in female cells that provides dosage compensation of X-linked genes to avoid overexpression, presents special vulnerabilities that can contribute to the disease process. Disruption of X inactivation can result in loss of dosage compensation with expression from previously sequestered genes, imbalance of gene products, and altered endogenous material out of normal epigenetic context. In addition, the human X has significant differences compared to other species and these differences can contribute to the frequency and intensity of the autoimmune disease in humans as well as the types of autoantigens encountered. Here a link is demonstrated between autoimmune diseases, such as systemic lupus erythematosus, and the X chromosome by discussing cases in which typically non-autoimmune disorders complicated with X chromosome abnormalities also present lupus-like symptoms. The discussion is then extended to the reported spatial and temporal associations of the inactive X chromosome with the nucleolus. When frequent episodes of cellular stress occur, the inactive X chromosome may be disrupted and inadvertently become involved in the nucleolar stress response. Development of autoantigens, many of which are at least transiently components of the nucleolus, is then described. Polyamines, which aid in nucleoprotein complex assembly in the nucleolus, increase further during cell stress, and appear to have an important role in the autoimmune disease process. Autoantigenic endogenous material can potentially be stabilized by polyamines. This presents a new paradigm for autoimmune diseases: that many are antigen-driven and the autoantigens originate from altered endogenous material due to episodes of cellular stress that disrupt epigenetic control. This suggests that epigenetics and the X chromosome are important aspects of autoimmune diseases. © 2015 Brooks and Renaudineau.

Bagacean C.,European University of Brittany | Bagacean C.,University of Medicine and Pharmacy, Cluj-Napoca | Zdrenghea M.,University of Medicine and Pharmacy, Cluj-Napoca | Zdrenghea M.,Ion Chiricuta Institute of Oncology | And 4 more authors.
Immunotherapy | Year: 2016

Over the last two decades, anti-CD20 monoclonal antibody (mAb) therapy has improved patient outcome in B-cell malignancies, and confirmed CD20 as an important target in chronic lymphocytic leukemia (CLL). Until recently, the gold standard was based on the utilization of rituximab combined with chemotherapy (fludarabine and cyclophosphamide), but patients often relapse. Next, with our better understanding of mAb engineering, anti-CD20 mAb therapy has evolved with the development of new mAb permitting significant clinical responses by improving pharmacokinetics, safety, activity and immunogenicity. Last but not least, the development of key tumoral tyrosine kinase inhibitors and their association with anti-CD20 mAb is a work in progress with promising results. © 2016 Future Medicine Ltd.

Mohr A.,French Institute of Health and Medical Research | Renaudineau Y.,French Institute of Health and Medical Research | Renaudineau Y.,Laboratory of Immunology and Immunotherapy | Bagacean C.,French Institute of Health and Medical Research | And 5 more authors.
OncoImmunology | Year: 2016

Chronic lymphocytic leukemia (CLL) is characterized by an abnormal expansion of mature B cells in the bone marrow and their accumulation in blood and secondary lymphoid organs. Tumor CLL cells share expression of various surface molecules with many subsets of B cells and have several common characteristics with regulatory B cells (B regs). However, the identification of B regs and their role in CLL remain elusive. The aim of this review is to summarize recent works regarding the regulatory and phenotypic characteristic of B regs and their associated effects on the immune system. It is also meant to highlight their potential importance with regards to the immunotherapeutic response. © 2016 Taylor & Francis Group, LLC.

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