Publications by authors named "Emmanuel Xystrakis"

Liver transplantation (LT) is a successful treatment for patients with liver failure. However, organ shortage results in over 11% of patients losing their chance of a transplant attributed to liver decompensation (LD) and death. Ischemia/reperfusion injury (IRI) following conventional cold storage (CS) is a major cause of injury leading to graft loss after LT.

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Article Synopsis
  • The study explores how different liver donation methods (living donors, brain death, and cardiac death) impact the behavior and function of liver T-cells, which play a role in organ injury during transplantation.
  • Researchers isolated T-cells from liver perfusate and analyzed their characteristics, finding that memory CD8 T-cells were more prevalent in livers from brain-dead donors, showing increased cytotoxic activity.
  • The results suggest that brain death influences liver T-cell function, potentially leading to more liver damage, which could inform therapeutic strategies to improve organ quality before transplantation.
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Background: Understanding of immune mechanisms underpinning asthma has emerged from studies in adults. It is increasingly recognised, both immunologically and in the development of novel therapies, that adult responses cannot be used accurately to predict those of children.

Methods: Using a well-defined paediatric cohort of severe therapy-resistant asthma (STRA) patients, we investigated cytokine profiles in the airway by analysis of bronchoalveolar lavage fluid.

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1α,25-Dihydroxyvitamin D3 (1α25VitD3) has potent immunomodulatory properties. We have previously demonstrated that 1α25VitD3 promotes human and murine IL-10-secreting CD4(+) T cells. Because of the clinical relevance of this observation, we characterized these cells further and investigated their relationship with Foxp3(+) regulatory T (Treg) cells.

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Changes in monocytes and their subsets (CD14(hi)/CD16(neg), CD14(hi)/CD16(pos) and CD14(lo)/CD16(pos)) have been described in several diseases. The combination of CD14, CD16 and HLA-DR has been suggested to discriminate monocytes from the CD16(pos) /HLA-DR(neg) NK-cells and neutrophils but no data exist whether this strategy can be used in situations when monocyte HLA-DR expression is pathologically reduced. Monocytes and their subsets were concurrently identified through negative (exclusion of CD66b(pos) neutrophils, CD56(pos) NKcells, CD19(pos) B-cells, and CD3(pos) T-cells) and positive gating (inclusion of monocytes by expression of CD14, CD16, and HLA-DR) strategies on 30 occasions [9 healthy controls (HC) and 21 patients with conditions associated with low monocyte HLA-DR expression].

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Signaling through the TLR family of molecular pattern recognition receptors has been implicated in the induction of innate and adaptive immune responses. A role for TLR signaling in the maintenance and/or regulation of Treg function has been proposed, however its functional relevance remains unclear. Here we have shown that TLR9 is highly expressed by human Treg secreting the antiinflammatory cytokine IL-10 induced following stimulation of blood and tissue CD3+ T cells in the presence of 1alpha,25-dihydroxyvitamin D3 (1alpha25VitD3), the active form of Vitamin D, with or without the glucocorticoid dexamethasone.

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Purpose Of Review: Regulatory T cells have been identified as key players in the maintenance of peripheral tolerance, which prevents inappropriate immune responses to both self-antigens and innocuous allergens. This review aims to provide an update on our current understanding of the therapeutic potential of naturally occurring and adaptive regulatory T cell subsets in allergic and asthmatic disease.

Recent Findings: Evidence is emerging that regulatory T cells control aberrant immune responses to allergens in health and exhibit impaired function in active disease.

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Allergic diseases, including asthma, are chronic inflammatory disorders originating from an aberrant immune response to innocuous antigens in our environment (allergens). In susceptible individuals, sensitization to allergen leads to the induction of allergen-specific T-helper type 2 (Th2) responses and immunoglobulin E (IgE) production. Subsequent challenge with allergen results in IgE-mediated mast cell activation and the recruitment and activation of effector cells, leading to clinical symptoms of disease.

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We previously reported that human CD4+ Tregs secrete high levels of IL-10 when stimulated in the presence of dexamethasone and calcitriol (vitamin D3). We now show that following stimulation by allergen, IL-10-secreting Tregs inhibit cytokine secretion by allergen-specific Th2 cells in an IL-10-dependent manner. A proportion of patients with severe asthma fail to demonstrate clinical improvement upon glucocorticoid therapy, and their asthma is characterized as glucocorticoid resistant (SR, abbreviation derived from "steroid resistant").

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Differential cytokine production by T cells plays an important role in the outcome of the immune response. We show that the level of CD45RC expression differentiates rat CD8 T cells in two subpopulations, CD45RC(high) and CD45RC(low), that have different cytokine profiles and functions. Upon in vitro stimulation, in an Ag-presenting cell-independent system, CD45RC(high) CD8 T cells produce IL-2 and IFN-gamma while CD45RC(low) CD8 T cells produce IL-4, IL-10, and IL-13.

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The immune system contains natural regulatory T cells that control the magnitude of the immune response during physiologic and pathologic conditions. Although this suppressive function was historically attributed to CD8 T cells, most recent reports have focused on natural regulatory CD4 T cells. In the present study, we describe a new subset of natural CD8 regulatory T cells in normal healthy animals.

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Graft-versus-host disease (GvHD) is a major complication of allogeneic bone marrow transplantation and occurs when donor T cells react with histo-incompatible recipient's antigens. In the present study, we analyzed the contribution of CD4 T cell subsets, defined according to their CD45RC expression level, in the development of acute and chronic GvHD. For this purpose, we used the model of GvHD induced in rats when parental lymphocytes are transferred to irradiated (LEWxBN) F1 hybrid recipients.

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Differential cytokine production by T cells plays an important role in regulating the nature of an immune response. In the rat, Brown-Norway (BN) and Lewis (LEW) strains differ markedly in their susceptibility to develop either type 1 or type 2-mediated autoimmune manifestations. BN rats are susceptible to type 2-dependent systemic autoimmunity, while LEW rats are resistant.

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