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AIMS/HYPOTHESIS: Tolerance induction in lymph nodes can be mediated by both haematopoietic cells (e.g. specific dendritic cells subsets) and by non-haematopoietic cells (e.g. lymph node stromal cells [LNSCs]) when they present peripheral tissue antigens to autoreactive T cells. LNSCs normally regulate T cell trafficking and survival and help to maintain peripheral tolerance by exerting immunosuppressive effects. However, whether autoimmunity can be associated with defective tolerogenic functions of LNSCs is unknown and studies aimed at characterising LNSCs in humans are lacking. We hypothesised that dysregulated T cell responses in pancreatic lymph nodes (PLNs) from donors with type 1 diabetes and from NOD mice may be associated with altered LNSC function. METHODS: We analysed PLNs from donors with type 1 diabetes and NOD mice for LNSC distribution and phenotype using flow cytometry. We assessed the expression of tolerance-related genes in different subsets of LNSCs from human donors, as well as in a population of dendritic cells enriched in autoimmune regulator (AIRE)+ cells and identified as HLA-DRhigh CD45low. RESULTS: The relative frequency of different LNSC subsets was altered in both donors with type 1 diabetes and NOD mice, and both MHC class II and programmed death-ligand 1 (PD-L1) expression were upregulated in human type 1 diabetes. Tolerance-related genes showed similar expression profiles between mouse and human LNSCs at steady state but were generally upregulated in the context of human type 1 diabetes, while, at the same time, many such genes were downregulated in the AIRE-enriched dendritic cell population. CONCLUSION/INTERPRETATION: Our study shows that LNSCs are substantially altered in type 1 diabetes, but, surprisingly, they exhibit an enhanced tolerogenic phenotype along with increased antigen-presenting potential, which may indicate an attempt to offset dendritic cell-related tolerogenic defects in tolerance. Thus, LNSCs could constitute alternative therapeutic targets in which to deliver antigens to help re-establish tolerance and prevent or treat type 1 diabetes. DATA AVAILABILITY: All data generated or analysed during this study are included in the published article (and its online supplementary files). Biomark gene expression data were deposited on the Mendeley repository at https://data.mendeley.com/datasets/d9rdzdmvyf/1 . Any other raw datasets are available from the corresponding author on reasonable request. No applicable resources were generated or analysed during the current study.
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Diabetes Mellitus Tipo 1/patología , Ganglios Linfáticos/patología , Páncreas/patología , Células del Estroma/citología , Animales , Presentación de Antígeno , Antígenos , Autoinmunidad , Células Dendríticas/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Femenino , Citometría de Flujo , Expresión Génica , Humanos , Tolerancia Inmunológica/inmunología , Terapia de Inmunosupresión , Antígenos Comunes de Leucocito/metabolismo , Ratones , Ratones Endogámicos NOD , Fenotipo , Linfocitos T/citologíaRESUMEN
AIMS/HYPOTHESIS: Pancreatic lymph nodes (PLNs) are critical sites for the initial interaction between islet autoantigens and autoreactive lymphocytes, but the histology of PLNs in tissue from individuals with type 1 diabetes has not been analysed in detail. The aim of this study was to examine PLN tissue sections from healthy donors compared with those at risk of, or with recent-onset and longer-duration type 1 diabetes. METHODS: Immunofluorescence staining was used to examine PLN sections from the following donor groups: non-diabetic (n=15), non-diabetic islet autoantibody-positive (n=5), recent-onset (≤1.5 years duration) type 1 diabetes (n=13), and longer-duration type 1 diabetes (n=15). Staining for CD3, CD20 and Ki67 was used to detect primary and secondary (germinal centre-containing) follicles and CD21 and CD35 to detect follicular dendritic cell networks. RESULTS: The frequency of secondary follicles was lower in the recent-onset type 1 diabetes group compared with the non-diabetic control group. The presence of insulitis (as evidence of ongoing beta cell destruction) and diagnosis of type 1 diabetes at a younger age, however, did not appear to be associated with a lower frequency of secondary follicles. A higher proportion of primary B cell follicles were observed to lack follicular dendritic cell networks in the recent-onset type 1 diabetes group. CONCLUSIONS/INTERPRETATION: Histological analysis of rare PLNs from individuals with type 1 diabetes suggests a previously unrecognised phenotype comprising decreased primary B cell follicle frequency and fewer follicular dendritic cell networks in recent-onset type 1 diabetes.
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Linfocitos B/citología , Diabetes Mellitus Tipo 1/inmunología , Centro Germinal/inmunología , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/patología , Páncreas/patología , Adolescente , Adulto , Anciano , Animales , Autoanticuerpos/inmunología , Autoantígenos/inmunología , Niño , Preescolar , Estudios de Cohortes , Células Dendríticas/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Femenino , Cabras , Humanos , Procesamiento de Imagen Asistido por Computador , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Antígeno Ki-67/metabolismo , Masculino , Ratones , Microscopía Fluorescente , Fenotipo , Conejos , Adulto JovenRESUMEN
The mechanisms of autoimmune reactivity onset in type 1 diabetes (T1D) remain elusive despite extensive experimentation and discussion. We reconsider several key aspects of the early stages of autoimmunity at four levels: islets, pancreatic lymph nodes, thymic function and peripheral immune homeostasis. Antigen presentation is the islets and has the capacity to provoke immune sensitization, either in the process of physiological neonatal ß cell apoptosis or as a consequence of cytolytic activity of self-reactive thymocytes that escaped negative regulation. Diabetogenic effectors are efficiently expanded in both the islets and the lymph nodes under conditions of empty lymphoid niches during a period of time coinciding with a synchronized wave of ß cell apoptosis surrounding weaning. A major drive of effector cell activation and expansion is inherent peripheral lymphopenia characteristic of neonates, though it remains unclear when is autoimmunity triggered in subjects displaying hyperglycemia in late adolescence. Our analysis suggests that T1D evolves through coordinated activity of multiple physiological mechanisms of stimulation within specific characteristics of the neonate immune system.
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Autoinmunidad , Diabetes Mellitus Tipo 1/inmunología , Animales , Apoptosis , Autoantígenos/inmunología , Susceptibilidad a Enfermedades , Homeostasis , Humanos , Sistema Inmunológico/citología , Sistema Inmunológico/inmunología , Sistema Inmunológico/metabolismo , Vigilancia Inmunológica , Inflamación/inmunología , Islotes Pancreáticos/citología , Islotes Pancreáticos/inmunología , Islotes Pancreáticos/metabolismo , Activación de Linfocitos , Linfocitos T/inmunología , Linfocitos T/metabolismoRESUMEN
Autoimmune diseases are characterized by the stimulation of an excessive immune response to self-tissues by inner and/or outer organism factors. Common characteristics in their etiology include a complex genetic predisposition and environmental triggers as well as the implication of the major histocompatibility (MHC) locus on human chromosome 6p21. A restraint number of non-MHC susceptibility genes, part of the genetic component of type 1 diabetes have been identified in human and in animal models, while the complete spectrum of genes involved remains unknown. We elaborate herein patterns of chromosomal organization of 162 genes differentially expressed in the pancreatic lymph nodes of Non-Obese Diabetic mice, carefully selected by early sub-phenotypic evaluation (presence or absence of insulin autoantibodies). Chromosomal assignment of these genes revealed a non-random distribution on five chromosomes (47%). Significant gene enrichment was observed in particular for two chromosomes, 6 and 7. While a subset of these genes coding for secreted proteins showed significant enrichment on both chromosomes, the overall pool of genes was significantly enriched on chromosome 7. The significance of this unexpected gene distribution on the mouse genome is discussed in the light of novel findings indicating that genes affecting common diseases map to recombination "hotspot" regions of mammalian genomes. The genetic architecture of transcripts differentially expressed in specific stages of autoimmune diabetes offers novel venues towards our understanding of patterns of inheritance potentially affecting the pathological disease mechanisms.
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Introduction. Primary amyloidosis is a disorder resulting from the deposition of fibrillary protein in extracellular tissue. Diagnosis of primary amyloidosis in the celiac/para-pancreatic lymph nodes via endoscopic ultrasound-guided fine needle aspiration has not been reported in the literature. In this article, we report our first observation. Our patient is a 64-year-old Caucasian man who was referred to our institution from an outlying hospital for recurrent abdominal pain. Radiological imaging revealed an enlarged abdominal lymph node that was already biopsied under computed tomography needle guidance but diagnosis was not achieved on pathological examination. At our institution, endoscopic ultrasound-guided fine needle aspiration showed enlarged para-celiac/pancreatic lymph nodes. Endosonography-guided fine needle aspiration revealed the diagnosis of primary amyloidosis. The patient tolerated the procedure well with follow-up as an outpatient. Conclusions. Lymph node involvement in amyloidosis is not uncommon. However, the involvement of the pancreatic/celiac lymph nodes by amyloidosis is obscure in this case. This case shows a rare presentation of amyloidosis diagnosed for the first time by the technique of endosonography-guided fine needle aspiration. In the future, this might serve as an establishment to standardize diagnosing abdominal lymph node amyloidosis, once suspected, by endosonography-guided fine needle aspiration.
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Gene therapy mediated by bone marrow-derived hematopoietic stem cells (BM-HSC) has been widely used in treating genetic deficiencies in both pre-clinical and clinical settings. Using mitotically inactive cell-targeting lentivirus with separate promoters for our gene of interest (the murine MHC class II (MHCII) chaperone, invariant chain (Ii)) and a GFP reporter, we monitored the expression and function of introduced Ii in various types of professional antigen presenting cells (B cells, macrophages and DC) from different organs (spleen, pancreatic lymph nodes (PLN), BM and blood). Ii and GFP were detected. Ii levels correlated with GFP levels only in macrophages and monocytes from spleen, monocytes from PLN and macrophage precursors from blood. By cell type, Ii levels in PLN cells were more similar to those in spleen cells than to those in blood or BM cells. Functionally, Ii expressed in PLN or spleen had more effect on MHCII abundance than Ii expressed in BM or blood. The results have implications for analysis of the outcomes of gene therapy when both therapeutic and reporter genes are introduced. The findings also have implications for understanding the development of immune molecule function.
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Células de la Médula Ósea/citología , Regulación de la Expresión Génica , Trasplante de Células Madre Hematopoyéticas , Células Madre Hematopoyéticas/metabolismo , Transgenes/genética , Animales , Células Presentadoras de Antígenos/citología , Células Presentadoras de Antígenos/metabolismo , Antígenos de Diferenciación de Linfocitos B/genética , Antígenos de Diferenciación de Linfocitos B/metabolismo , Células Cultivadas , Genes Reporteros , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células Madre Hematopoyéticas/citología , Antígenos de Histocompatibilidad Clase II/genética , Antígenos de Histocompatibilidad Clase II/metabolismo , Lentivirus/genética , Ganglios Linfáticos/metabolismo , Ratones , Regiones Promotoras Genéticas , Bazo/metabolismoRESUMEN
Rotavirus infection has been proposed to enhance progression towards type 1 diabetes in at-risk children. Rhesus monkey rotavirus (RRV) accelerates diabetes onset in non-obese diabetic (NOD) and T cell receptor transgenic NOD8.3 mice. Infected NOD mice show virus spread to pancreatic lymph nodes (PLN) and mesenteric lymph nodes (MLN), induction of a serum T helper 1-biased specific antibody response and proinflammatory cytokine mRNA expression in PLN and islets. Here, we analysed the effects of RRV infection on intestinal responses and the activation of antigen presenting cells (APC), T cells and B cells in PLN, MLN, spleen and islets. Diabetes acceleration by RRV was associated with minimal immune activation in Peyer's patches. Increased proinflammatory cytokine expression by APC, including dendritic cells, was observed exclusively in the PLN, while cytokine expression by T cells was detected in islets, PLN, MLN and spleen. RRV infection of NOD8.3 mice increased IFNγ expression by CD8(+) T cells, which primarily recognise an islet autoantigen. A peptide corresponding to RRV VP7 amino acids 5-13, with sequence similarity to this islet autoantigen, did not induce activation or proliferation of NOD8.3 mouse T cells. RRV infection of NOD mice elevated B cell MHC I expression in PLN and MLN, and increased the B cell-mediated proliferation of islet antigen-specific CD8(+) T cells. These studies demonstrate that RRV infection of NOD mice activates APC, T cells and B cells at sites where autoreactive lymphocytes accumulate, in association with proinflammatory cytokine expression and an increased capacity to present antigen. Taken together with previous findings, these data support a possible role for bystander activation in type 1 diabetes acceleration by RRV.