20 research outputs found
Cytotoxic dendritic cells generated from cancer patients.
International audienceKnown for years as professional APCs, dendritic cells (DCs) are also endowed with tumoricidal activity. This dual role of DC as killers and messengers may have important implications for tumor immunotherapy. However, the tumoricidal activity of DCs has mainly been investigated in animal models. Cancer cells inhibit antitumor immune responses using numerous mechanisms, including the induction of immunosuppressive/ tolerogenic DCs that have lost their ability to present Ags in an immunogenic manner. In this study, we evaluated the possibility of generating tumor killer DCs from patients with advanced-stage cancers. We demonstrate that human monocyte-derived DCs are endowed with significant cytotoxic activity against tumor cells following activation with LPS. The mechanism of DC-mediated tumor cell killing primarily involves peroxynitrites. This observed cytotoxic activity is restricted to immature DCs. Additionally, after killing, these cytotoxic DCs are able to activate tumor Ag-specific T cells. These observations may open important new perspectives for the use of autologous cytotoxic DCs in cancer immunotherapy strategies
Splenic TFH expansion participates in B-cell differentiation and antiplatelet-antibody production during immune thrombocytopenia
Antiplatelet-antibody-producing B cells play a key role immune thrombocytopenia (ITP) pathogenesis; however, little is known about T-cell dysregulations that support B-cell differentiation. During the past decade, T follicular helper cells (TFHs) have been characterized as the main T-cell subset within secondary lymphoid organs that promotes B-cell differentiation leading to antibody class-switch recombination and secretion. Herein, we characterized TFHs within the spleen of 8 controls and 13 ITP patients. We show that human splenic TFHs are the main producers of interleukin (IL)-21, express CD40 ligand(CD154), and are located within the germinal center of secondary follicles. Compared with controls, splenic TFH frequency is higher in ITP patients and correlates with germinal center and plasma cell percentages that are also increased. In vitro, IL-21 stimulation combined with an anti-CD40 agonist antibody led to the differentiation of splenic B cells into plasma cells and to the secretion of antiplatelet antibodies in ITP patients. Overall, these results point out the involvement of TFH in ITP pathophysiology and the potential interest of IL-21 and CD40 as therapeutic targets in ITP
Etude des populations lymphocytaires T au cours de lâanĂ©mie hĂ©molytique auto immune
Warm autoimmune hemolytic anemia (wAIHA) is a rare acquired autoimmune disease mediated by antibodies targeting red blood cells. The involvement of CD4 T helper (Th) cells has been scarcely explored, with most findings extrapolated from animal models. Although it is still debated, wAIHA is thought to be associated with a pro-inflammatory Th17 polarization and a quantitative deficit of regulatory T cells (Treg).In this work, we performed the first concomitant quantification of circulating effector T lymphocytes (Teff) and Treg, associated with functional and transcriptomic analyses of Treg in human wAIHA at diagnosis. We observed a shift towards a Th17 polarization of Teff and a decrease in circulating Treg, notably effector Treg. This quantitative deficit was associated with an impairment of Treg capability to inhibit Teff proliferation and promoted the Th17 skewing. Treg deficiency was related to the diminished Foxp3 protein level, the master transcription factor maintaining phenotype stability and suppressive functions of Treg.The transcriptomic profile of patients' Treg revealed: |1. A strong engagement of TNF signaling pathways in Treg, consistent with serum TNF-α increase in patients. |2. A possible role of post-translational mechanisms leading to Foxp3 downregulation accounting for Treg dysfunctions.Through this work, we report two novel and major observations for the understanding of wAIHA pathophysiology: the increase of serum TNF-α in patients at diagnosis, and both a quantitative and functional deficit of circulating Treg. Although the mechanistic aspects and the links between these two observations remain to be clarified, they allow us to consider new therapeutic axes for patients such as Treg strengthening and/or the neutralization of TNF-α production.L'anĂ©mie hĂ©molytique auto-immune Ă auto-anticorps chaud (AIHA) est une maladie auto-immune rare et acquise, mĂ©diĂ©e par des anticorps ciblant les globules rouges. L'implication des lymphocytes T helper (Th) CD4+ dans la physiopathologie a Ă©tĂ© peu Ă©tudiĂ©e et la plupart des rĂ©sultats sont extrapolĂ©s de modĂšles murins. Bien que cela soit encore dĂ©battu, lâAIHA pourrait ĂȘtre associĂ©e Ă une polarisation pro-inflammatoire de type Th17 et Ă un dĂ©ficit quantitatif en lymphocytes T rĂ©gulateurs (Treg).Au cours de ce travail, nous avons rĂ©alisĂ© la premiĂšre Ă©tude concomitante des LT effecteurs et des Treg circulants, ainsi quâune Ă©tude fonctionnelle et transcriptomique des Treg de patients atteints dâAHAI au diagnostic.Nous avons observĂ© une orientation des LT effecteurs vers une polarisation Th17 accompagnĂ©e dâune diminution des Treg circulants, principalement des Treg effecteurs. Ce dĂ©ficit quantitatif est associĂ© Ă une diminution de la capacitĂ© des Treg Ă inhiber la prolifĂ©ration des LT effecteurs, ce qui semble favoriser dâavantage la polarisation Th17.Le dĂ©ficit en Treg est associĂ© Ă une diminution du niveau dâexpression de la protĂ©ine Foxp3, le facteur de transcription dominant des Treg, qui assure la stabilitĂ© de leur phĂ©notype et le maintien de leurs fonctions suppressives. Le profil transcriptomique des Treg des patients a rĂ©vĂ©lĂ© : |1. Un fort engagement des voies de signalisation du TNF dans les Treg, en accord avec une augmentation significative du TNF-α sĂ©rique chez les patients. |2. Un rĂŽle possible de mĂ©canismes post-traductionnels conduisant Ă la dĂ©gradation de Foxp3 Ă lâorigine des dysfonctionnements des Treg.A travers ce travail nous rapportons deux observations inĂ©dites et importantes pour la comprĂ©hension de la physiopathologie de lâAHAI, lâaugmentation du TNF-α sĂ©rique chez les patients AHAI au diagnostic ainsi que le dĂ©ficit quantitatif et fonctionnel des Treg circulants. Bien que les aspects mĂ©canistiques ou les liens entre ces deux observations restent Ă prĂ©ciser, elles nous permettent dâores et dĂ©jĂ dâenvisager de nouveaux axes thĂ©rapeutiques pour les patients tels que le renforcement des populations Treg et/ou la neutralisation de la production du TNF-α
T cell lymphocytes in warm autoimmune hemolytic anemia
L'anĂ©mie hĂ©molytique auto-immune Ă auto-anticorps chaud (AIHA) est une maladie auto-immune rare et acquise, mĂ©diĂ©e par des anticorps ciblant les globules rouges. L'implication des lymphocytes T helper (Th) CD4+ dans la physiopathologie a Ă©tĂ© peu Ă©tudiĂ©e et la plupart des rĂ©sultats sont extrapolĂ©s de modĂšles murins. Bien que cela soit encore dĂ©battu, lâAIHA pourrait ĂȘtre associĂ©e Ă une polarisation pro-inflammatoire de type Th17 et Ă un dĂ©ficit quantitatif en lymphocytes T rĂ©gulateurs (Treg).Au cours de ce travail, nous avons rĂ©alisĂ© la premiĂšre Ă©tude concomitante des LT effecteurs et des Treg circulants, ainsi quâune Ă©tude fonctionnelle et transcriptomique des Treg de patients atteints dâAHAI au diagnostic.Nous avons observĂ© une orientation des LT effecteurs vers une polarisation Th17 accompagnĂ©e dâune diminution des Treg circulants, principalement des Treg effecteurs. Ce dĂ©ficit quantitatif est associĂ© Ă une diminution de la capacitĂ© des Treg Ă inhiber la prolifĂ©ration des LT effecteurs, ce qui semble favoriser dâavantage la polarisation Th17.Le dĂ©ficit en Treg est associĂ© Ă une diminution du niveau dâexpression de la protĂ©ine Foxp3, le facteur de transcription dominant des Treg, qui assure la stabilitĂ© de leur phĂ©notype et le maintien de leurs fonctions suppressives. Le profil transcriptomique des Treg des patients a rĂ©vĂ©lĂ© : |1. Un fort engagement des voies de signalisation du TNF dans les Treg, en accord avec une augmentation significative du TNF-α sĂ©rique chez les patients. |2. Un rĂŽle possible de mĂ©canismes post-traductionnels conduisant Ă la dĂ©gradation de Foxp3 Ă lâorigine des dysfonctionnements des Treg.A travers ce travail nous rapportons deux observations inĂ©dites et importantes pour la comprĂ©hension de la physiopathologie de lâAHAI, lâaugmentation du TNF-α sĂ©rique chez les patients AHAI au diagnostic ainsi que le dĂ©ficit quantitatif et fonctionnel des Treg circulants. Bien que les aspects mĂ©canistiques ou les liens entre ces deux observations restent Ă prĂ©ciser, elles nous permettent dâores et dĂ©jĂ dâenvisager de nouveaux axes thĂ©rapeutiques pour les patients tels que le renforcement des populations Treg et/ou la neutralisation de la production du TNF-α.Warm autoimmune hemolytic anemia (wAIHA) is a rare acquired autoimmune disease mediated by antibodies targeting red blood cells. The involvement of CD4 T helper (Th) cells has been scarcely explored, with most findings extrapolated from animal models. Although it is still debated, wAIHA is thought to be associated with a pro-inflammatory Th17 polarization and a quantitative deficit of regulatory T cells (Treg).In this work, we performed the first concomitant quantification of circulating effector T lymphocytes (Teff) and Treg, associated with functional and transcriptomic analyses of Treg in human wAIHA at diagnosis. We observed a shift towards a Th17 polarization of Teff and a decrease in circulating Treg, notably effector Treg. This quantitative deficit was associated with an impairment of Treg capability to inhibit Teff proliferation and promoted the Th17 skewing. Treg deficiency was related to the diminished Foxp3 protein level, the master transcription factor maintaining phenotype stability and suppressive functions of Treg.The transcriptomic profile of patients' Treg revealed: |1. A strong engagement of TNF signaling pathways in Treg, consistent with serum TNF-α increase in patients. |2. A possible role of post-translational mechanisms leading to Foxp3 downregulation accounting for Treg dysfunctions.Through this work, we report two novel and major observations for the understanding of wAIHA pathophysiology: the increase of serum TNF-α in patients at diagnosis, and both a quantitative and functional deficit of circulating Treg. Although the mechanistic aspects and the links between these two observations remain to be clarified, they allow us to consider new therapeutic axes for patients such as Treg strengthening and/or the neutralization of TNF-α production
ĂTUDE DES CELLULES LYMPHOĂDES INNĂES SPLĂNIQUES HUMAINES ET DE LEURS IMPLICATIONS AU COURS DE LA THROMBOPĂNIE IMMUNOLOGIQUE
ĂTUDE DES CELLULES LYMPHOĂDES INNĂES SPLĂNIQUES HUMAINES ET DE LEURS IMPLICATIONS AU COURS DE LA THROMBOPĂNIE IMMUNOLOGIQUEDe dĂ©couverte rĂ©cente, les ILC ont Ă©tĂ© caractĂ©risĂ©es comme cellules effectrices de lâimmunitĂ© innĂ©ecapables de moduler les rĂ©ponses lymphocytaires T et B dans les muqueuses. Cependant, leur rĂŽle ausein des organes lymphoĂŻdes chez lâHomme au cours des maladies auto-immunes nâa pas Ă©tĂ© Ă©tudiĂ©.La thrombopĂ©nie immunologique est une maladie auto-immune responsable dâune destructionpĂ©riphĂ©rique des plaquettes associĂ©e Ă une production mĂ©dullaire inadaptĂ©e. La rate joue un rĂŽlecentral dans la physiopathologie en Ă©tant le site principal de la destruction des plaquettes et du maintiende la rĂ©ponse auto-immune. La splĂ©nectomie faisant partie du traitement de cette maladie, cela donneune occasion unique dâĂ©tudier la rĂ©ponse immunitaire au sein dâun organe lymphoĂŻde secondaire aucours dâune maladie auto-immune chez lâHomme.Dans le cadre de ce projet nous avons Ă©tudiĂ© le phĂ©notype des ILC splĂ©niques dans des conditionsphysiologiques et au cours du PTI.LâĂ©tude du compartiment splĂ©nique humain dans des conditions physiologiques nous a permis dequantifier les ILC totales qui reprĂ©sentent 0,24 % des cellules lymphoĂŻdes et dâidentifier les diffĂ©rentessous populations dâILC splĂ©niques. Les ILC totales expriment majoritairement le rĂ©cepteur de chĂ©mokineCCR6 et sĂ©crĂštent dâimportantes quantitĂ©s de TNF-α. Les ILC3 sont les plus reprĂ©sentĂ©es, constituĂ©esessentiellement dâILC3 NCR-, tandis que les ILC2 sont trĂšs peu nombreuses dans la rate.Au cours du PTI, la frĂ©quence des ILC splĂ©niques totales est similaire Ă celle des tĂ©moins, en revancheelles sont plus nombreuses Ă exprimer CD62L, ligand de MadCam, exprimĂ© dans la zone marginale.Les ILC1, plus nombreuses dans les rates des patients, contribuent vraisemblablement Ă alimenterlâenvironnement pro-inflammatoire splĂ©nique. Elles sont plus nombreuses Ă exprimer CXCR3, CD62L etĂ sĂ©crĂ©ter de lâIL-2 et de lâIFN-Îł. La frĂ©quence des ILC3 splĂ©niques totales est similaire entre les patientset les tĂ©moins mais la proportion de cellules sĂ©crĂ©tant du GM-CSF est plus importante au cours du PTI.De mĂȘme, la sous-population dâILC3 « naĂŻves » NCR-CD62L+, est augmentĂ©e et sa frĂ©quence est corrĂ©lĂ©eĂ celle des ILC1 CD62L+.Enfin, la rĂ©partition des sous-populations dâILC splĂ©niques des patients non rĂ©pondeurs Ă lasplĂ©nectomie diffĂšre des patients rĂ©pondeurs par une diminution des ILC3 NCR-CD62L+, des ILC3 NCR+et ILC1 CD62L+, au profit des ILC3 NCR-HLA-DR+. Lâaugmentation de cette population dâILC3 NCR-HLADR+nâexprimant pas ou peu les molĂ©cules de costimulation et lâaugmentation de la proportion dâILC3sĂ©crĂ©tant de lâIL-10 et peu dâIL-2 sont autant de signes en faveur dâun rĂŽle principalement rĂ©gulateurdes ILC3 dans la rate des patients non rĂ©pondeurs Ă la splĂ©nectomie.Ces rĂ©sultats viennent enrichir les connaissances sur la physiopathologie du PTI et sur la contributiondes ILC1 et des ILC3 Ă lâenvironnement pro-inflammatoire splĂ©nique. Ils ouvrent Ă©galement de nouvellesperspectives sur une possible implication des ILC3 dans le maintien de la tolĂ©rance, notamment chezles patients non rĂ©pondeurs Ă la splĂ©nectomie
Etude des populations lymphocytaires T au cours de lâanĂ©mie hĂ©molytique auto immune
Warm autoimmune hemolytic anemia (wAIHA) is a rare acquired autoimmune disease mediated by antibodies targeting red blood cells. The involvement of CD4 T helper (Th) cells has been scarcely explored, with most findings extrapolated from animal models. Although it is still debated, wAIHA is thought to be associated with a pro-inflammatory Th17 polarization and a quantitative deficit of regulatory T cells (Treg).In this work, we performed the first concomitant quantification of circulating effector T lymphocytes (Teff) and Treg, associated with functional and transcriptomic analyses of Treg in human wAIHA at diagnosis. We observed a shift towards a Th17 polarization of Teff and a decrease in circulating Treg, notably effector Treg. This quantitative deficit was associated with an impairment of Treg capability to inhibit Teff proliferation and promoted the Th17 skewing. Treg deficiency was related to the diminished Foxp3 protein level, the master transcription factor maintaining phenotype stability and suppressive functions of Treg.The transcriptomic profile of patients' Treg revealed: |1. A strong engagement of TNF signaling pathways in Treg, consistent with serum TNF-α increase in patients. |2. A possible role of post-translational mechanisms leading to Foxp3 downregulation accounting for Treg dysfunctions.Through this work, we report two novel and major observations for the understanding of wAIHA pathophysiology: the increase of serum TNF-α in patients at diagnosis, and both a quantitative and functional deficit of circulating Treg. Although the mechanistic aspects and the links between these two observations remain to be clarified, they allow us to consider new therapeutic axes for patients such as Treg strengthening and/or the neutralization of TNF-α production.L'anĂ©mie hĂ©molytique auto-immune Ă auto-anticorps chaud (AIHA) est une maladie auto-immune rare et acquise, mĂ©diĂ©e par des anticorps ciblant les globules rouges. L'implication des lymphocytes T helper (Th) CD4+ dans la physiopathologie a Ă©tĂ© peu Ă©tudiĂ©e et la plupart des rĂ©sultats sont extrapolĂ©s de modĂšles murins. Bien que cela soit encore dĂ©battu, lâAIHA pourrait ĂȘtre associĂ©e Ă une polarisation pro-inflammatoire de type Th17 et Ă un dĂ©ficit quantitatif en lymphocytes T rĂ©gulateurs (Treg).Au cours de ce travail, nous avons rĂ©alisĂ© la premiĂšre Ă©tude concomitante des LT effecteurs et des Treg circulants, ainsi quâune Ă©tude fonctionnelle et transcriptomique des Treg de patients atteints dâAHAI au diagnostic.Nous avons observĂ© une orientation des LT effecteurs vers une polarisation Th17 accompagnĂ©e dâune diminution des Treg circulants, principalement des Treg effecteurs. Ce dĂ©ficit quantitatif est associĂ© Ă une diminution de la capacitĂ© des Treg Ă inhiber la prolifĂ©ration des LT effecteurs, ce qui semble favoriser dâavantage la polarisation Th17.Le dĂ©ficit en Treg est associĂ© Ă une diminution du niveau dâexpression de la protĂ©ine Foxp3, le facteur de transcription dominant des Treg, qui assure la stabilitĂ© de leur phĂ©notype et le maintien de leurs fonctions suppressives. Le profil transcriptomique des Treg des patients a rĂ©vĂ©lĂ© : |1. Un fort engagement des voies de signalisation du TNF dans les Treg, en accord avec une augmentation significative du TNF-α sĂ©rique chez les patients. |2. Un rĂŽle possible de mĂ©canismes post-traductionnels conduisant Ă la dĂ©gradation de Foxp3 Ă lâorigine des dysfonctionnements des Treg.A travers ce travail nous rapportons deux observations inĂ©dites et importantes pour la comprĂ©hension de la physiopathologie de lâAHAI, lâaugmentation du TNF-α sĂ©rique chez les patients AHAI au diagnostic ainsi que le dĂ©ficit quantitatif et fonctionnel des Treg circulants. Bien que les aspects mĂ©canistiques ou les liens entre ces deux observations restent Ă prĂ©ciser, elles nous permettent dâores et dĂ©jĂ dâenvisager de nouveaux axes thĂ©rapeutiques pour les patients tels que le renforcement des populations Treg et/ou la neutralisation de la production du TNF-α
Immune Thrombocytopenia: Recent Advances in Pathogenesis and Treatments
Immune thrombocytopenia (ITP) is a rare autoimmune disease due to both a peripheral destruction of platelets and an inappropriate bone marrow production. Although the primary triggering factors of ITP remain unknown, a loss of immune toleranceâmostly represented by a regulatory T-cell defectâallows T follicular helper cells to stimulate autoreactive splenic B cells that differentiate into antiplatelet antibody-producing plasma cells. Glycoprotein IIb/IIIa is the main target of antiplatelet antibodies leading to platelet phagocytosis by splenic macrophages, through interactions with Fc gamma receptors (FcÎłRs) and complement receptors. This allows macrophages to activate autoreactive T cells by their antigen-presenting functions. Moreover, the activation of the classical complement pathway participates to platelet opsonization and also to their destruction by complement-dependent cytotoxicity. Platelet destruction is also mediated by a FcÎłR-independent pathway, involving platelet desialylation that favors their binding to the Ashwell-Morell receptor and their clearance in the liver. Cytotoxic T cells also contribute to ITP pathogenesis by mediating cytotoxicity against megakaryocytes and peripheral platelets. The deficient megakaryopoiesis resulting from both the humoral and the cytotoxic immune responses is sustained by inappropriate levels of thrombopoietin, the major growth factor of megakaryocytes. The better understanding of ITP pathogenesis has provided important therapeutic advances. B cell-targeting therapies and thrombopoietin-receptor agonists (TPO-RAs) have been used for years. New emerging therapeutic strategies that inhibit FcÎłR signaling, the neonatal Fc receptor or the classical complement pathway, will deeply modify the management of ITP in the near future
Altered distribution and function of splenic innate lymphoid cells in adult chronic immune thrombocytopenia
IF 7.607International audienceInnate lymphoid cells (ILCs) have been characterized as innate immune cells capable to modulate the immune response in the mucosae. Human ILCs have been rarely described in secondary lymphoid organs except in tonsils. Moreover, their function and phenotype in human secondary lymphoid organs during autoimmune diseases have never been studied. We took advantage of splenectomy as a treatment of immune thrombocytopenia (ITP) to describe and compare splenic ILC from 18 ITP patients to 11 controls. We first confirmed that ILC3 represented the most abundant ILC subset in human non-inflamed spleens, accounting for 90% of total ILC, and that they were mostly constituted of NKp44- cells. On the contrary, proportions of ILC1 and ILC2 in spleens were lower than in blood. Splenic IL-2- and IFN-Îł-producing ILC1 were increased in ITP. While the frequencies of total splenic ILC3 were similar in the two groups, splenic GM-CSF-producing ILC3 were increased in ITP. This is the first description of human ILC in a major secondary lymphoid organ during an autoimmune disease, ITP. We observed an expansion of splenic ILC1 that could participate to the Th1 skewing, while the increased production of GM-CSF by splenic ILC3 could stimulate splenic macrophages which play a key role in ITP pathophysiology
Splenic and Circulating Human T Follicular Helper Cell Regulation By B Cell Depleting Therapy during Immune Thrombocytopenia
T Lymphocyte Inhibition by Tumor-Infiltrating Dendritic Cells Involves Ectonucleotidase CD39 but Not Arginase-1
T lymphocytes activated by dendritic cells (DC) which present tumor antigens play a key role in the antitumor immune response. However, in patients suffering from active cancer, DC are not efficient at initiating and supporting immune responses as they participate to T lymphocyte inhibition. DC in the tumor environment are functionally defective and exhibit a characteristic of immature phenotype, different to that of DC present in nonpathological conditions. The mechanistic bases underlying DC dysfunction in cancer responsible for the modulation of T-cell responses and tumor immune escape are still being investigated. Using two different mouse tumor models, we showed that tumor-infiltrating DC (TIDC) are constitutively immunosuppressive, exhibit a semimature phenotype, and impair responder T lymphocyte proliferation and activation by a mechanism involving CD39 ectoenzyme