Réponse des Lymphocytes T Gamma-Delta à deux Complications de la transplantation rénale (le Cytomégalovirus et les anticorps spécifiques du donneur)

La transplantation rénale est la stratégie de suppléance rénale la plus performante. Le renforcement des thérapeutiques ciblant la réponse cellulaire T (i) a conduit à réévaluer la réponse allogénique humorale et (ii) a souligné deux complications majeures de la pression immunosuppressive : l infection à cytomégalovirus CMV et le risque de cancer. Dans le travail présenté ici, nous analysons d abord l impact histologique de deux de ces facteurs de détérioration de l allogreffon rénal : l infection à CMV avant une biopsie sur indication et la pathogénicité des anticorps anti-HLA dirigés contre le donneur, détectés par des techniques d identification en Single Antigen in situ dans le greffon. Nous montrons ensuite comment les lymphocytes T (LT) g Vd2neg font le lien entre CMV et DSA : induits par le CMV, les LT g Vd2neg participent aux lésions médiées par les DSA par leur capacité à réaliser une lyse dépendante de l anticorps (ADCC) impliquant le CD16. En plus de cette nouvelle fonction allogénique indirecte, les LT g Vd2neg possèdent une double réactivité anti-CMV et anti-tumoral. Nous présentons ici un modèle où les lymphocytes T g V 2neg s activent spécifiquement de façon TCR dépendante par la reconnaissance d un marqueur d intégrité épithéliale (EphA2) : ils détournent le mécanisme d interaction classique d EphA2 avec ses ligands naturels éphrines A1 et A4 pour s en faire un signal de costimulation, en s appuyant sur le contexte de stress pour renforcer son activation. Collectivement, nos résultats contribuent à mieux préciser la bioréactivité et le rôle des LT g V 2neg en transplantation rénale. Nos données suggèrent que chez l'homme, a fortiori lorsqu il est immunodéprimé, les LT g constituent un compartiment de surveillance lymphoide du stress, capable de censurer la dérégulation des cellules infectées ou transformées et de prendre part à la réponse allogénique par un mécanisme d ADCC.Kidney transplant is the most performant strategy for renal replacement therapy. Increasing treatment targetting T cell response has led (i) to reappraise the importance of humoral allogenic response, (ii) to underline two main complications subsequent to immunosuppressive pressure : cytomegalovirus infection and tumorigenesis. Here, we first report the pathological impact of two of these factors on kidney allograft deterioration : CMV infection prior a biopsy for cause and Donor Specific Alloantibodies (DSA) detected within the graft with single antigen flow bead assay. Then we showed that CMV-induced V 2neg g T cells are a new player and a potentially useful clinical biomarker in antibody-mediated lesions of kidney transplants. By engaging DSA on their Fcg-receptor CD16, g T cells participate in allograft lesions mediated by DSA through antibody-dependent cell cytotoxicity (ADCC). In addition to this new indirect allogenic function, CMV-induced V 2neg g T cells displayed a dual anti-CMV and anti-tumor reactivity. Finally, we here identified EphA2 as a new stress-regulated antigen targetting by a non V 2neg g T cell clone, which recognition implies the hijacking of the natural EphA2-ephrin interactions to activation. These data suggest that in humans, a fortiori when immunosuppressed, g T cells compose a lymphoid stress-surveillance compartment, capable of recognizing the dysregulated state of infected or transformed cells and to take part to allogenic response through an ADCC mechanism.BORDEAUX2-Bib. électronique (335229905) / SudocBORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Effect of a musical intervention on tolerance and efficacy of non-invasive ventilation in the ICU: study protocol for a randomized controlled trial (MUSique pour l’Insuffisance Respiratoire Aigue - Mus-IRA)

NIV protocol. (DOCX 103 kb

Natural killer cell degeneration exacerbates experimental arthritis in mice via enhanced interleukin-17 production

Objective. An altered phenotype and dysfunction of natural killer (NK) cells have been observed in patients with rheumatoid arthritis. The aim of this study was to determine whether dysregulated NK cells contribute to the pathogenesis of experimental arthritis. Methods. For initiation of collagen-induced arthritis (CIA), DBA/1J mice were immunized with type II collagen in Freund's adjuvant. Control mice were immunized with adjuvant alone. NK cells from the blood, spleens, and bone marrow of immunized mice were analyzed by flow cytometry. Levels of interleukin-17 (IL-17) secretion and autoantibody production were measured by enzyme-linked immunosorbent assays. Immunized mice in which NK cells were depleted by anti-asialo GM1 antibody treatment were assessed for the development of CIA. Moreover, sorting-purified NK cells from both mice with CIA and control mice were analyzed for cytokine gene expression. Results. We observed markedly reduced frequencies of NK cells in the blood and spleens of mice with CIA compared with the frequencies in adjuvant-treated control mice. Upon NK cell depletion, immunized mice displayed an early onset of arthritis with more severe clinical symptoms, which correlated with increased plasma cell generation and autoantibody production. Moreover, a substantially increased number of IL-17-secreting cells in synovial tissue and more pronounced joint damage were observed. Freshly isolated NK cells from mice with CIA showed markedly reduced expression of interferon-γ (IFNγ). Furthermore, coculture of normal NK cells and CD4+ T cells revealed that NK cells strongly suppressed production of Th17 cells via their IFNγ production. Conclusion. These results suggest that NK cells play a protective role in the development of experimental arthritis, an effect that is possibly mediated by suppressing Th17 cell generation via IFNγ production. © 2008, American College of Rheumatology.postprin

Responsiveness of human T lymphocytes to bacterial superantigens presented by cultured rheumatoid arthritis synoviocytes

Objective . Type B fibroblastic synoviocytes are abundant in inflamed joints of patients with rheumatoid arthritis (RA), and can secrete cytokines and other mediators of inflammation. The aim of this study was to determine whether cell lines derived from RA type B synoviocytes could also serve as accessory cells for T lymphocyte activation. Methods . Cells from RA synoviocyte lines, with or without preculture in interferon-Γ (IFNΓ), were cultured with purified peripheral blood T cells, in the presence or absence of superantigens or other accessory cell–dependent T cell mitogens. T cell proliferation was measured by thymidine incorporation, and synoviocyte surface markers were analyzed by flow cytometry. Results . RA type B synoviocyte lines were potent accessory cells for T cell responses to bacterial superantigens or lectins, and direct cell-cell contact was required. Preculture in IFNΓ augmented synoviocyte expression of major histocompatibility complex (MHC) class II molecules and of ligands for some T cell costimulatory receptors, but synoviocyte accessory cell function was evident even in the absence of IFNΓ. Blocking studies using monoclonal antibodies supported the notion of a role for CD2, CD11a/CD18 and MHC class II molecules in synoviocyte-dependent T cell activation. Monoclonal antibodies against IFNΓ, interleukin-1Β (IL-1Β), IL-6, IL-8, and tumor necrosis factor Α failed to block the T cell proliferative responses, but anti–IL-2 was strongly inhibitory. Conclusion . Cultured RA type B synoviocytes can perform some of the functions of professional antigen-presenting cells. If such cells have similar properties in vivo, they may be important participants in activation of immune responses, in addition to their previously described synthetic and proinflammatory roles. If RA synovial tissue T cells, like normal peripheral blood T cells, can respond to superantigens presented by synoviocytes, this interaction could be important in the pathogenesis of RA.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37807/1/1780390117_ftp.pd

Peripheral blood T-cell signatures from high-resolution immune phenotyping of γδ and αβ T-cells in younger and older subjects in the Berlin Aging Study II

Background Aging and latent infection with Cytomegalovirus (CMV) are thought to be major factors driving the immune system towards immunosenescence, primarily characterized by reduced amounts of naïve T-cells and increased memory T-cells, potentially associated with higher morbidity and mortality. The composition of both major compartments, γδ as well as αβ T-cells, is altered by age and CMV, but detailed knowledge of changes to the γδ subset is currently limited. Results Here, we have surveyed a population of 73 younger (23–35 years) and 144 older (62–85 years) individuals drawn from the Berlin Aging Study II, investigating the distribution of detailed differentiation phenotypes of both γδ and αβ T-cells. Correlation of frequencies and absolute counts of the identified phenotypes with age and the presence of CMV revealed a lower abundance of Vδ2-positive and a higher amount of Vδ1-positive cells. We found higher frequencies of late-differentiated and lower frequencies of early-differentiated cells in the Vδ1+ and Vδ1-Vδ2-, but not in the Vδ2+ populations in elderly CMV-seropositive individuals confirming the association of these Vδ2-negative cells with CMV-immunosurveillance. We identified the highest Vδ1:Vδ2 ratios in the CMV-seropositive elderly. The observed increased CD4:CD8 ratios in the elderly were significantly lower in CMV-seropositive individuals, who also possessed a lower naïve and a larger late-differentiated compartment of CD8+ αβ T-cells, reflecting the consensus in the literature. Conclusions Our findings illustrate in detail the strong influence of CMV on the abundance and differentiation pattern of γδ T-cells as well as αβ T-cells in older and younger people. Mechanisms responsible for the phenotypic alterations in the γδ T-cell compartment, associated both with the presence of CMV and with age require further clarification

Endothelin-Dependent Vasoconstriction in Human Uterine Artery: Application to Preeclampsia

BACKGROUND: Reduced uteroplacental perfusion, the initiating event in preeclampsia, is associated with enhanced endothelin-1 (ET-1) production which feeds the vasoconstriction of uterine artery. Whether the treatments of preeclampsia were effective on ET-1 induced contraction and could reverse placental ischemia is the question addressed in this study. We investigated the effect of antihypertensive drugs used in preeclampsia and of ET receptor antagonists on the contractile response to ET-1 on human uterine arteries. METHODOLOGY/PRINCIPAL FINDINGS: Experiments were performed, ex vivo, on human uterine artery samples obtained after hysterectomy. We studied variations in isometric tension of arterial rings in response to the vasoconstrictor ET-1 and evaluated the effects of various vasodilators and ET-receptor antagonists on this response. Among antihypertensive drugs, only dihydropyridines were effective in blocking and reversing the ET-1 contractile response. Their efficiency, independent of the concentration of ET-1, was only partial. Hydralazine, alpha-methyldopa and labetalol had no effect on ET-1 induced contraction which is mediated by both ET(A) and ET(B) receptors in uterine artery. ET receptors antagonists, BQ-123 and BQ-788, slightly reduced the amplitude of the response to ET-1. Combination of both antagonists was more efficient, but it was not possible to reverse the maximal ET-1-induced contraction with antagonists used alone or in combination. CONCLUSION: Pharmacological drugs currently used in the context of preeclampsia, do not reverse ET-1 induced contraction. Only dihydropyridines, which partially relax uterine artery previously contracted with ET-1, might offer interesting perspectives to improve placental perfusion

Elevated serum levels of soluble CD154 in children with juvenile idiopathic arthritis

<p>Abstract</p> <p>Objective</p> <p>Cytokines play important roles in mediating inflammation in autoimmunity. Several cytokines are elevated in serum and synovial fluid samples from children with Juvenile Idiopathic Arthritis (JIA). Soluble CD154 (sCD154) is elevated in other autoimmune disorders, but has not been characterized in JIA. Our objectives were to determine if sCD154 is elevated in JIA, and to examine correlations between sCD154 and other inflammatory cytokines.</p> <p>Methods</p> <p>Serum from 77 children with JIA and 81 pediatric controls was analyzed for interleukin (IL)1β, IL2, IL4, IL5, IL6, IL8, IL10, IL12, IL13, sCD154, interferon-γ (IFNγ), soluble IL2 receptor (sIL2R), and tumor necrosis factor-α (TNFα), using the Luminex Multi-Analyte Profiling system. Differences in levels of cytokines between cases and controls were analyzed. Logistic regression was also performed.</p> <p>Results</p> <p>sCD154 was significantly elevated in cases compared to controls (p < 0.0001). IL1β, IL5, IL6, IL8, IL13, IFNγ, sIL2R, and TNFα were also significantly elevated in JIA. Levels of sCD154 were highly correlated with IL1β, IL6, IL8, and TNFα (p < 0.0001). Logistic regression analysis suggested that IL6 (odds ratio (OR): 1.4, p < 0.0001), sCD154 (OR: 1.1, p < 0.0001), and TNFα (OR: 1.1, p < 0.005) were positively associated with JIA, while IL10 (OR: 0.5, p < 0.002) was protective. sCD154 was elevated in all JIA subtypes, with highest levels among more severe subtypes. IL1β, IL6, IL8, sIL2R and TNFα were also elevated in several JIA subtypes.</p> <p>Conclusion</p> <p>Serum levels of sCD154, IL1β, IL6, IL8, sIL2R and TNFα are elevated in most JIA subtypes, suggesting a major role for sCD154, and these cytokines and cytokine receptors in the pathogenesis of JIA.</p

Clonal selection in the human Vδ1 T cell repertoire indicates γδ TCR-dependent adaptive immune surveillance

γδ T cells are considered to be innate-like lymphocytes that respond rapidly to stress without clonal selection and differentiation. Here we use next-generation sequencing to probe how this paradigm relates to human Vδ2neg T cells, implicated in responses to viral infection and cancer. The prevalent Vδ1 T cell receptor (TCR) repertoire is private and initially unfocused in cord blood, typically becoming strongly focused on a few high-frequency clonotypes by adulthood. Clonal expansions have differentiated from a naive to effector phenotype associated with CD27 downregulation, retaining proliferative capacity and TCR sensitivity, displaying increased cytotoxic markers and altered homing capabilities, and remaining relatively stable over time. Contrastingly, Vδ2+ T cells express semi-invariant TCRs, which are present at birth and shared between individuals. Human Vδ1+ T cells have therefore evolved a distinct biology from the Vδ2+ subset, involving a central, personalized role for the γδ TCR in directing a highly adaptive yet unconventional form of immune surveillance

The effect of cigarette smoking, alcohol consumption and fruit and vegetable consumption on IVF outcomes: A review and presentation of original data

Background - Lifestyle factors including cigarette smoking, alcohol consumption and nutritional habits impact on health, wellness, and the risk of chronic diseases. In the areas of in-vitro fertilization (IVF) and pregnancy, lifestyle factors influence oocyte production, fertilization rates, pregnancy and pregnancy loss, while chronic, low-grade oxidative stress may underlie poor outcomes for some IVF cases. Methods - Here, we review the current literature and present some original, previously unpublished data, obtained from couples attending the PIVET Medical Centre in Western Australia. Results - During the study, 80 % of females and 70 % of male partners completed a 1-week diary documenting their smoking, alcohol and fruit and vegetable intake. The subsequent clinical outcomes of their IVF treatment such as quantity of oocytes collected, fertilization rates, pregnancy and pregnancy loss were submitted to multiple regression analysis, in order to investigate the relationship between patients, treatment and the recorded lifestyle factors. Of significance, it was found that male smoking caused an increased risk of pregnancy loss (p = 0.029), while female smoking caused an adverse effect on ovarian reserve. Both alcohol consumption (β = 0.074, p < 0.001) and fruit and vegetable consumption (β = 0.034, p < 0.001) had positive effects on fertilization. Conclusion - Based on our results and the current literature, there is an important impact of lifestyle factors on IVF clinical outcomes. Currently, there are conflicting results regarding other lifestyle factors such as nutritional habits and alcohol consumption, but it is apparent that chronic oxidative stress induced by lifestyle factors and poor nutritional habits associate with a lower rate of IVF success