Search results for "Lymph nodes"

Melanoma of unknown primary: New perspectives for an old story

2021

Melanoma of unknown primary site (MUP) comprises 3-4 % of all melanomas. It mostly presents in lymph nodes (LNs), followed by subcutaneous sites, and visceral organs; nevertheless, there is a trend of increase in the relative incidence of visceral counterpart in recent years. Spontaneous regression of the primary lesion is a well-established theory, based on the evidence that melanoma can undergo regression at the primary site. MUP and stage-matched melanoma of known primary site (MKP) share similar prognostic factors. The survival rate of patients with MUP has been compared to those with stage-matched MKP. Multiple studies conducted before the era of novel therapy with immune checkpoint or…

Lymphatic Endothelial Cells Control Initiation of Lymph Node Organogenesis

2017

Lymph nodes (LNs) are strategically situated throughout the body at junctures of the blood vascular and lymphatic systems to direct immune responses against antigens draining from peripheral tissues. The current paradigm describes LN development as a programmed process that is governed through the interaction between mesenchymal lymphoid tissue organizer (LTo) cells and hematopoietic lymphoid tissue inducer (LTi) cells. Using cell-type-specific ablation of key molecules involved in lymphoid organogenesis, we found that initiation of LN development is dependent on LTi-cell-mediated activation of lymphatic endothelial cells (LECs) and that engagement of mesenchymal stromal cells is a succeedi…

Nutritional Wheat Amylase-Trypsin Inhibitors Promote Intestinal Inflammation via Activation of Myeloid Cells.

2016

Background & Aims Wheat amylase-trypsin inhibitors (ATIs) are nutritional activators of innate immunity, via activation of the toll-like receptor 4 (TLR4) on myeloid cells. We aimed to characterize the biologic activity of ATIs in various foods and their effect on intestinal inflammation. Methods We selected 38 different gluten-containing and gluten-free products, either unprocessed (such as wheat, rye, barley, quinoa, amaranth, soya, lentils, and rice) or processed (such as pizza, pasta, bread, and biscuits). ATIs were extracted and their biological activities determined in TLR4-responsive mouse and human cell lines. Effects of oral ATIs on intestinal inflammation were determined in health…

In cutaneous leishmaniasis, induction of retinoic acid in skin-derived Langerhans cells is not sufficient for induction of parasite persistence-media…

2017

Down-Regulation of CD62L Shedding in T Cells by CD39+ Regulatory T Cells Leads to Defective Sensitization in Contact Hypersensitivity Reactions

2016

Injection of regulatory T cells (Tregs) followed by sensitization with 2,4,6-trinitrochlorobenzene induced a transient increase in size and cellularity of skin-draining lymph nodes (LNs) in mice. This led us to hypothesize that Tregs may affect the trafficking of T cells from and to peripheral LNs. Two to three hours after sensitization, we found fewer CD8+ T cells expressing CD62L in LNs compared with untreated controls. Injection of wild-type Tregs prevented this down-regulation of CD62L. In contrast, Tregs devoid of the adenosine triphosphate (ATP)-degrading ecto-enzyme CD39 were unable to do so. As for the mechanism of CD62L regulation, we found that ATP, which is released in skin upon …

Microenvironmental regulation of the IL-23R/IL-23 axis overrides chronic lymphocytic leukemia indolence

2018

Although the progression of chronic lymphocytic leukemia (CLL) requires the cooperation of the microenvironment, the exact cellular and molecular mechanisms involved are still unclear. We investigated the interleukin (IL)-23 receptor (IL-23R)/IL-23 axis and found that circulating cells from early-stage CLL patients with shorter time-to-treatment, but not of those with a more benign course, expressed a defective form of the IL-23R complex lacking the IL-12Rβ1 chain. However, cells from both patient groups expressed the complete IL-23R complex in tissue infiltrates and could be induced to express the IL-12Rβ1 chain when cocultured with activated T cells or CD40L+ cells. CLL cells activated in…

Lymph node - an organ for T-cell activation and pathogen defense.

2016

The immune system is a multicentered organ that is characterized by intimate interactions between its cellular components to efficiently ward off invading pathogens. A key constituent of this organ system is the distinct migratory activity of its cellular elements. The lymph node represents a pivotal meeting point of immune cells where adaptive immunity is induced and regulated. Additionally, besides barrier tissues, the lymph node is a critical organ where invading pathogens need to be eliminated in order to prevent systemic distribution of virulent microbes. Here, we explain how the lymph node is structurally and functionally organized to fulfill these two critical functions - pathogen de…

Is there any therapeutic role of pelvic and para-aortic lymphadenectomy in apparent early stage epithelial ovarian cancer?

2020

Objective: The therapeutic role of pelvic and para-aortic lymphadenectomy in surgical staging of apparent early-stage epithelial ovarian cancer (eEOC) is still under debate. The aim of this study was to evaluate the potential therapeutic role of systematic lymphadenectomy in patients with eEOC. Methods: Multi-center retrospective cohort study, comparing women with apparent eEOC who underwent comprehensive bilateral pelvic and para-aortic lymphadenectomy (defined as ≥20 lymph nodes) versus patients receiving no lymphadenectomy or lymph node sampling, from 05/1985 to 12/2016. Patients with bulky nodes at CT-scan and those without complete intra-peritoneal surgical staging were excluded. Only …

Genetic proof for the transient nature of the Th17 phenotype

2010

IL-17-producing CD4(+) T cells (Th17) have been classified as a new T helper cell subset. Using an IL-17 fate mapping mouse strain, which genetically fixes the memory of IL-17 expression, we demonstrate that IL-17A/F-expressing T helper cells generated either in vitro or in vivo are not a stable T-cell subset. Upon adoptive transfer of IL-17F-reporter-positive Th17 cells to RAG-deficient or WT animals, encephalitogenic Th17 cells partially lose IL-17 expression and upregulate IFN-γ. Additionally, we show that Th1 cells can convert in vivo to IL-17A/IFN-γ-coexpressing cells in the mesenteric lymph nodes (mLN). Our data classify IL-17A and IL-17F as cytokines produced transiently in response …

B?cells are not required for T?cell priming in low zone tolerance to contact allergens and contact hypersensitivity

2004

Low zone tolerance (LZT) to contact allergens is induced by epicutaneous exposure to haptens in subsensitizing doses resulting in an inhibition of contact hypersensitivity (CHS), which, in contrast, occurs after sensitization with immunogenic doses of allergens. Performing the protocol of tolerance induction resulted in robust LZT to allergens in B cell-deficient mice in vivo, indicating that B cells are not required for the induction and effector phase of LZT. However, CHS reactions in vivo were restricted in B cell-deficient mice as compared to wild-type (WT) mice. In contrast, analysis of hapten-specific T cell activation in vitro revealed a strong proliferative response of T cells deriv…