Hélène Trébeden-Nègre

Long‐term persistence of clonally expanded T cells in patients with polymyositis

Polymyositis is a CD8+ T‐cell–mediated disease. T‐cell clonal expansions are observed at disease onset, but little is known about their persistence over time. Qualitative and quantitative spectratyping demonstrated that PM relapse features dramatically perturbed blood T‐cell repertoires but is not associated with the emergence of new T‐cell clones. It is striking that patients in remission also maintained all their T‐cell repertoire abnormalities. The clonally expanded T‐cells displayed a memory phenotype, expressed intracellular perforin, and dramatically responded to IL‐2, showing a potential to be reactivated upon appropriate conditions. These results indicate that persistent T‐cell clonal expansion is an important feature of polymyositis. Ann Neurol 2004

Correlation of clinical and virologic responses to antiviral treatment and regulatory T cell evolution in patients with hepatitis C virus–induced mixed cryoglobulinemia vasculitis

OBJECTIVEnMixed cryoglobulinemia (MC) vasculitis is an autoimmune disorder associated with chronic hepatitis C virus (HCV) infection. We previously reported that MC vasculitis is associated with a quantitative defect of peripheral blood regulatory T cells. The aim of this study was to prospectively evaluate the evolution of this defect during the course of antiviral treatment.nnnMETHODSnTreg cell frequencies and numbers were analyzed in 131 patients with chronic HCV infection (including 66 with MC vasculitis) and 20 healthy volunteer donors. Measurements were taken before, during, and after treatment with PEGylated interferon alfa-2b plus ribavirin.nnnRESULTSnAt baseline, patients with MC vasculitis had a significantly lower frequency and number of Treg cells than did patients without MC vasculitis. Complete remission of MC vasculitis following antiviral treatment was associated with a significant increase in Treg cell levels compared with baseline. In contrast, Treg cell levels in nonresponders or partial responders, which did not differ from those in complete responders at baseline, remained unchanged over the course of the study.nnnCONCLUSIONnThe strong positive correlation between clinical responses and Treg cell levels provides further support for the central role of Treg cells in the pathogenesis of HCV-induced MC vasculitis and emphasizes the dual role of Treg cells in chronic HCV infection: while Treg cells may hinder viral elimination, they also limit autoimmune injury.

Efficient transduction and selection of human T-lymphocytes with bicistronic Thy1/HSV1-TK retroviral vector produced by a human packaging cell line.

T‐cells expressing the HSV1‐TK suicide gene can be used for the control of graft‐versus‐host disease following allogeneic stem cell transplantation. To develop clinical trials based on such a strategy, we have generated under good manufacturing procedures a novel ‘split genome’ human packaging cell line (1704 cells).

Regulatory T Cell Content in the Bone Marrow Graft Does Not Predict the Occurrence of Acute GVHD

The subpopulation of regulatory T cells (Treg) was shown to play a key role in alloreactive responses. In allogeneic hematopoietic stem cell transplantation, several groups tested whether Treg content in transplants correlates with graft-versus-host disease (GVHD) with controversial results. In a retrospective study of 49 consecutive HLA-matched sibling transplantations, we studied the relationship between Treg content in bone marrow transplants and acute GVHD (aGVHD) occurrence. We observed a large variability in Treg in bone marrow grafts. However, contrary to previous observations in peripheral blood stem cells transplantation, we report that the Treg content of allogeneic bone marrow transplantation did not predict the occurrence of aGVHD.

Delayed recovery after autologous peripheral hematopoietic cell transplantation: potential effect of a high number of total nucleated cells in the graft.

BACKGROUND: Some patients demonstrate delayed recoveries after autologous hematopoietic stem cell transplantation despite infusion of an adequate number of CD34+ cells/kg and clinically stable status. Factors considered being possible predictors of this outcome in this context were explored.

IL-2 production by dendritic cells is not critical for the activation of cognate and innate effectors in draining lymph nodes

Dendritic cells (DC) are unique antigen‐presenting cells capable of triggering NK cell effector functions and priming naive T cells in vivo. Microbial stimulation induces early IL‐2 production by mouse DC. Previous reports demonstrated that IL‐2 is enriched at the site of DC/T cell interaction and promotes allogeneic T cell proliferation. However, the direct role of DC‐derived IL‐2 in the differentiation of cytotoxic T lymphocytes and in NK cell triggering in vivo has not been investigated. Lipopolysaccharide (LPS) stimulation of mouse bone morrow‐derived DC results in early IL‐2 production unless IL‐4 is introduced in DC cultures. Here we show that IL‐2 produced by LPS‐activated DC is dispensable for cognate T cell responses since IL‐2 loss of function DC elicit OVA‐specific Tc1 effector and memory lymphocytes in draining lymph nodes in a setting where ex vivo cultured DC do not transfer antigens to host DC. Moreover, adoptively transferred IL‐2 loss of function DC maintain their capacity to trigger NK cell proliferation/recruitment in lymph nodes. Therefore, immediate inducible IL‐2 production by DC following microbial infection might play a regulatory role at ports of entry rather than in secondary lymphoid organs.

Combination of IL-2, rapamycin, DNA methyltransferase and histone deacetylase inhibitors for the expansion of human regulatory T cells

FOXP3+ regulatory T cell (Treg) based cellular therapies represent promising therapeutic options in autoimmunity, allergy, transplantation and prevention of Graft Versus Host (GVH) Disease. Among human FOXP3-expressing CD4+T cells, only the CD45RA+ naïve Treg (nTreg) subset is suitable for in vitro expansion. However, FoxP3 expression decays in cells using currently described culture protocols. Rapamycin alone was not able to prevent FOXP3 loss in nTregs cells, as only a half of them maintained FOXP3 expression after 14 days of culture. In contrast we report a novel combined drug regimen that can drastically stabilize FOXP3 expression in cultured Tregs. IL-2, rapamycin, histone deacetylase and DNA methyltransferase inhibitors act in synergy to allow expansion of human regulatory T cells with sustained high expression of FOXP3 and CD15s with potent suppressive capacities in vitro and control of murine xeno-GVH reactions. Of note, an additional subsequent infusion of expanded nTreg cells did not improve survival of mice. Combination of IL-2, rapamycin, histone deacetylase and DNA methyltransferase inhibitors is optimal for the expansion in vitro of pure effective nTreg maintaining high levels of FOXP3 for therapeutic purposes.