Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 121
Filtrar
1.
Diabet Med ; 36(9): 1092-1099, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-30955221

RESUMEN

AIMS: Most people with Type 1 diabetes have low levels of persistent endogenous insulin production. The Diabetes Control and Complications Trial showed that close to diagnosis preserved endogenous insulin was associated with lower HbA1c , hypoglycaemia and complication rates, when intensively treated. We aimed to assess the clinical impact of persistent C-peptide on rate of hypoglycaemia and HbA1c in those with long duration (> 5 years) Type 1 diabetes. METHODS: We conducted a cross-sectional case-control study of 221 people (median age 24 years) with Type 1 diabetes. We confirmed ongoing endogenous insulin secretion by measuring C-peptide after a mixed-meal tolerance test. We compared self-reported hypoglycaemia (n = 160), HbA1c , insulin dose and microvascular complications (n = 140) in those with preserved and low C-peptide. RESULTS: Stimulated median (IQR) C-peptide was 114 (43, 273) pmol/l and < 3 (< 3, < 3) pmol/l in those with preserved and low C-peptide respectively. Participants with preserved C-peptide had lower reported monthly rates of hypoglycaemia, with 21% fewer symptomatic episodes, 5.9 vs. 7.5 [incidence rate ratio (IRR) 0.79, P = 0.001], and 65% fewer asymptomatic episodes, 1.0 vs. 2.9 (IRR 0.35, P < 0.001). Those with preserved C-peptide had a lower insulin dose (0.68 vs. 0.81 units/kg, P = 0.01) but similar HbA1c (preserved 69 vs. low 67 mmol/mol, P = 0.06). CONCLUSIONS: Adults with Type 1 diabetes and preserved endogenous insulin production receiving usual care in the UK have lower daily insulin doses and fewer self-reported hypoglycaemic episodes, but no difference in HbA1c . This is consistent with non-intensive treatment in previous studies, and suggests a need to consider therapy intensification to gain full benefit of preserved endogenous insulin.


Asunto(s)
Péptido C/sangre , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Hemoglobina Glucada/metabolismo , Hipoglucemia/sangre , Hipoglucemiantes/uso terapéutico , Adolescente , Adulto , Glucemia/análisis , Glucemia/metabolismo , Automonitorización de la Glucosa Sanguínea , Péptido C/metabolismo , Estudios de Casos y Controles , Estudios Transversales , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/epidemiología , Femenino , Hemoglobina Glucada/análisis , Humanos , Hipoglucemia/inducido químicamente , Hipoglucemia/epidemiología , Hipoglucemiantes/efectos adversos , Masculino , Pautas de la Práctica en Medicina/estadística & datos numéricos , Reino Unido/epidemiología , Adulto Joven
2.
Int J Pharm ; 562: 303-312, 2019 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-30910633

RESUMEN

Antigen specific immunotherapy aims to tolerise patients to specific autoantigens that are responsible for the pathology of an autoimmune disease. Immune tolerance is generated in conditions where the immune response is suppressed and thus gold nanoparticles (AuNPs) are an attractive drug delivery platform due to their anti-inflammatory effects and their potential to facilitate temporal and spatial delivery of a peptide autoantigen in conjunction with pro-tolerogenic elements. In this study we have covalently attached an autoantigen, currently under clinical evaluation for the treatment of type 1 diabetes (PIC19-A3 peptide), to AuNPs to create nanoscale (<5 nm), negatively charged (-40 to -60 mV) AuNP-peptide complexes for immunotherapy. We also employ a clinically approved microneedle delivery system, MicronJet600, to facilitate minimally-invasive intradermal delivery of the nanoparticle constructs to target skin-resident antigen presenting cells, which are known to be apposite target cells for immunotherapy. The AuNP-peptide complexes remain physically stable upon extrusion through microneedles and when delivered into ex vivo human skin they are able to diffuse rapidly and widely throughout the dermis (their site of deposition) and, perhaps more surprisingly, the overlying epidermal layer. Intracellular uptake was extensive, with Langerhans cells proving to be the most efficient cells at internalising the AuNP-peptide complex (94% of the local population within the treated region of skin). In vitro studies showed that uptake of the AuNP-peptide complexes by dendritic cells reduced the capacity of these cells to activate naïve T cells. This indicator of biological functionality encourages further development of the AuNP-peptide formulation, which is now being evaluated in clinical trials.


Asunto(s)
Autoantígenos/administración & dosificación , Oro/administración & dosificación , Inmunoterapia , Nanopartículas del Metal/administración & dosificación , Péptidos/administración & dosificación , Piel/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Transporte Biológico , Células Cultivadas , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Femenino , Humanos , Inyecciones Intradérmicas , Persona de Mediana Edad , Piel/citología , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología
3.
Genes Immun ; 18(3): 176-183, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28794505

RESUMEN

Tolerogenic dendritic cells (tolDCs) are assessed as immunomodulatory adjuvants to regulate autoimmunity. The underlying gene expression endorsing their regulatory features remains ill-defined. Using deep mRNA sequencing, we compared transcriptomes of 1,25-dihydroxyvitaminD3/dexametasone-modulated tolDCs with that of non-modulated mature inflammatory DCs (mDCs). Differentially expressed genes controlled cellular interactions, metabolic pathways and endorse tolDCs with the capacity to regulate cell activation through nutrient and signal deprivation, collectively gearing tolDCs into tolerogenic immune regulators. Gene expression differences correlated with protein expression, designating low CD86 and high CD52 on the cell surface as superior discriminators between tolDCs and mDCs. Of 37 candidate genes conferring risk to developing type 1 diabetes (T1D), 11 genes differentially expressed in tolDCs and mDCs regulated immune response and antigen-presenting activity. Differential-expressed transcripts of candidate risk loci for T1D suggest a role of these 'risk genes' in immune regulation, which targeting may modulate the genetic contribution to autoimmunity.


Asunto(s)
Autoinmunidad/genética , Células Dendríticas/inmunología , Diabetes Mellitus Tipo 1/genética , Tolerancia Inmunológica/genética , Transcriptoma , Presentación de Antígeno/genética , Antígeno B7-2/genética , Antígeno B7-2/metabolismo , Antígeno CD52/genética , Antígeno CD52/metabolismo , Calcitriol/farmacología , Línea Celular , Células Cultivadas , Células Dendríticas/efectos de los fármacos , Dexametasona/farmacología , Diabetes Mellitus Tipo 1/inmunología , Humanos
4.
Genes Immun ; 17(6): 342-8, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27467285

RESUMEN

Autoreactive CD8(+) T cells recognizing autoantigens expressed by pancreatic islets lead to the destruction of insulin-producing beta cells in type 1 diabetes (T1D), but these T cells also occur in healthy subjects. We tested the hypothesis that uncontrolled expansion of diabetogenic T cells in patients occurs, resulting from failure to activate apoptosis. We compared function, transcriptome and epigenetic regulation thereof in relation with fate upon repeated exposure to islet-autoantigen of islet autoreactive T cells from healthy and type 1 diabetic donors with identical islet epitope specificity and HLA-A2 restriction. Patient's T cells proliferated exponentially, whereas those of non-diabetic origin succumbed to cell death. Transcriptome analysis revealed reduced expression of TRAIL, TRAIL-R2, FAS and FASLG (members of the extrinsic apoptosis pathway) in patient-derived compared with healthy donor-derived T cells. This was mirrored by increased expression of microRNAs predicted to regulate these particular genes, namely miR-98, miR-23b and miR-590-5p. Gene-specific targeting by these microRNAs was confirmed using dual-luciferase reporter assays. Finally, transfection of these microRNAs into primary T cells reduced FAS and TRAIL mRNA underscoring their functional relevance. We propose that repression of pro-apoptotic pathways by microRNAs contributes to unrestricted expansion of diabetogenic cytotoxic T cells, implicating microRNA-mediated gene silencing in islet autoimmunity in T1D.


Asunto(s)
Apoptosis , Autoinmunidad , Linfocitos T CD8-positivos/fisiología , Diabetes Mellitus Tipo 1/inmunología , MicroARNs/metabolismo , Ligando Inductor de Apoptosis Relacionado con TNF/metabolismo , Receptor fas/metabolismo , Apoptosis/genética , Linfocitos T CD8-positivos/inmunología , Proliferación Celular , Supervivencia Celular , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Humanos , Células Secretoras de Insulina , Transcriptoma
5.
Clin Exp Immunol ; 185(2): 133-40, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-26861694

RESUMEN

The initiation of type 1 diabetes (T1D) requires a break in peripheral tolerance. New insights into neoepitope formation indicate that post-translational modification of islet autoantigens, for example via deamidation, may be an important component of disease initiation or exacerbation. Indeed, deamidation of islet autoantigens increases their binding affinity to the T1D highest-risk human leucocyte antigen (HLA) haplotypes HLA-DR3/DQ2 and -DR4/DQ8, increasing the chance that T cells reactive to deamidated autoantigens can be activated upon T cell receptor ligation. Here we investigated human pancreatic islets and inflammatory and tolerogenic human dendritic cells (DC and tolDC) as potential sources of deamidated islet autoantigens and examined whether deamidation is altered in an inflammatory environment. Islets, DC and tolDC contained tissue transglutaminase, the key enzyme responsible for peptide deamidation, and enzyme activity increased following an inflammatory insult. Islets treated with inflammatory cytokines were found to contain deamidated insulin C-peptide. DC, heterozygous for the T1D highest-risk DQ2/8, pulsed with native islet autoantigens could present naturally processed deamidated neoepitopes. HLA-DQ2 or -DQ8 homozygous DC did not present deamidated islet peptides. This study identifies both human islets and DC as sources of deamidated islet autoantigens and implicates inflammatory activation of tissue transglutaminase as a potential mechanism for islet and DC deamidation.


Asunto(s)
Amidas/química , Autoantígenos/inmunología , Autoantígenos/metabolismo , Células Dendríticas/inmunología , Diabetes Mellitus Tipo 1/inmunología , Islotes Pancreáticos/inmunología , Procesamiento Proteico-Postraduccional , Autoantígenos/biosíntesis , Autoantígenos/genética , Péptido C/inmunología , Células Dendríticas/fisiología , Antígenos HLA-DQ/inmunología , Antígeno HLA-DR3/inmunología , Humanos , Tolerancia Inmunológica , Inflamación/inmunología , Islotes Pancreáticos/citología , Islotes Pancreáticos/fisiología , Proteoma , Linfocitos T/inmunología , Transglutaminasas/metabolismo
7.
Genes Immun ; 17(1): 75-8, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26656450

RESUMEN

Cytotoxic T-lymphocyte-associated protein 4 (CTLA4) is a protein receptor that downregulates the immune system. CTLA4 gene variants associate with various autoimmune diseases, including type 1 diabetes. Fine mapping of the genetic risk has shown that the genomic region near CTLA4 marked by the single-nucleotide polymorphism (SNP) CT60A/G (rs3087243) acts as a susceptibility factor. Yet, the functional basis for the increased susceptibility conferred by rs3087243 remains unclear. We demonstrate that the length of the dinucleotide (AT)n repeat within the CTLA4 3' untranslated region (3'UTR) strongly associates with the risk of SNP CT60A/G (P<6.5 × 10(-72)). Genomic (AT)n repeat length inversely correlated with CTLA4 messenger RNA (mRNA) and protein levels in islet autoreactive T-cell lines. Transfer of a long (AT)n element into T cells lead to a reduction of mRNA compared to a short (AT)n element. Thus, this study provides evidence for a role of the CTLA4 3'UTR (AT)n repeat in the increased genetic risk for islet autoimmunity associated with the CTLA4 locus.


Asunto(s)
Regiones no Traducidas 3' , Antígeno CTLA-4/genética , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/inmunología , Repeticiones de Dinucleótido , Predisposición Genética a la Enfermedad , Linfocitos T/inmunología , Humanos , Procesamiento Postranscripcional del ARN
8.
Clin Exp Immunol ; 182(3): 251-60, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26206289

RESUMEN

Peptide immunotherapy (PIT) is a targeted therapeutic approach, involving administration of disease-associated peptides, with the aim of restoring antigen-specific immunological tolerance without generalized immunosuppression. In type 1 diabetes, proinsulin is a primary antigen targeted by the autoimmune response, and is therefore a strong candidate for exploitation via PIT in this setting. To elucidate the optimal conditions for proinsulin-based PIT and explore mechanisms of action, we developed a preclinical model of proinsulin autoimmunity in a humanized HLA-DRB1*0401 transgenic HLA-DR4 Tg mouse. Once proinsulin-specific tolerance is broken, HLA-DR4 Tg mice develop autoinflammatory responses, including proinsulin-specific T cell proliferation, interferon (IFN)-γ and autoantibody production. These are preventable and quenchable by pre- and post-induction treatment, respectively, using intradermal proinsulin-PIT injections. Intradermal proinsulin-PIT enhances proliferation of regulatory [forkhead box protein 3 (FoxP3(+))CD25(high) ] CD4 T cells, including those capable of proinsulin-specific regulation, suggesting this as its main mode of action. In contrast, peptide delivered intradermally on the surface of vitamin D3-modulated (tolerogenic) dendritic cells, controls autoimmunity in association with proinsulin-specific IL-10 production, but no change in regulatory CD4 T cells. These studies define a humanized, translational model for in vivo optimization of PIT to control autoimmunity in type 1 diabetes and indicate that dominant mechanisms of action differ according to mode of peptide delivery.


Asunto(s)
Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 1/terapia , Inmunoterapia , Péptidos/farmacología , Proinsulina/farmacología , Linfocitos T Reguladores/inmunología , Animales , Autoanticuerpos/inmunología , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/inmunología , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/inmunología , Diabetes Mellitus Tipo 1/patología , Antígeno HLA-DR4/genética , Antígeno HLA-DR4/inmunología , Cadenas HLA-DRB1/genética , Cadenas HLA-DRB1/inmunología , Humanos , Interferón gamma/genética , Interferón gamma/inmunología , Interleucina-10/genética , Interleucina-10/inmunología , Ratones , Ratones Transgénicos , Linfocitos T Reguladores/patología
9.
Clin Exp Immunol ; 179(3): 398-413, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25302633

RESUMEN

Several ß cell antigens recognized by T cells in the non-obese diabetic (NOD) mouse model of type 1 diabetes (T1D) are also T cell targets in the human disease. While numerous antigen-specific therapies prevent diabetes in NOD mice, successful translation of rodent findings to patients has been difficult. A human leucocyte antigen (HLA)-transgenic mouse model incorporating human ß cell-specific T cells might provide a better platform for evaluating antigen-specific therapies. The ability to study such T cells is limited by their low frequency in peripheral blood and the difficulty in obtaining islet-infiltrating T cells from patients. We have worked to overcome this limitation by using lentiviral transduction to 'reprogram' primary human CD8 T cells to express three T cell receptors (TCRs) specific for a peptide derived from the ß cell antigen islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP265-273 ) and recognized in the context of the human class I major histocompatibility complex (MHC) molecule HLA-A2. The TCRs bound peptide/MHC multimers with a range of avidities, but all bound with at least 10-fold lower avidity than the anti-viral TCR used for comparison. One exhibited antigenic recognition promiscuity. The ß cell-specific human CD8 T cells generated by lentiviral transduction with one of the TCRs released interferon (IFN)-γ in response to antigen and exhibited cytotoxic activity against peptide-pulsed target cells. The cells engrafted in HLA-A2-transgenic NOD-scid IL2rγ(null) mice and could be detected in the blood, spleen and pancreas up to 5 weeks post-transfer, suggesting the utility of this approach for the evaluation of T cell-modulatory therapies for T1D and other T cell-mediated autoimmune diseases.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , Diabetes Mellitus Tipo 1/inmunología , Vectores Genéticos/genética , Inmunoterapia Adoptiva/métodos , Células Secretoras de Insulina/inmunología , Lentivirus/genética , Linfocitos T Citotóxicos/inmunología , Animales , Linfocitos T CD8-positivos/trasplante , Supervivencia Celular , Glucosa-6-Fosfatasa/inmunología , Antígeno HLA-A2/genética , Antígeno HLA-A2/metabolismo , Humanos , Células Jurkat , Ratones , Ratones Endogámicos NOD , Ratones Noqueados , Ratones Transgénicos , Fragmentos de Péptidos/inmunología , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores de Interleucina-2/genética , Linfocitos T Citotóxicos/trasplante
10.
Curr Diab Rep ; 13(5): 704-12, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23943207

RESUMEN

Type 1 diabetes (T1D) is an autoimmune disease in which the insulin-producing beta-cells are destroyed. Islet or pancreas transplantation can restore insulin secretion and are established therapies for subgroups of T1D patients. Long-term insulin-independence is, however, hampered by recurrent autoimmunity and rejection. Accurate monitoring of these immune events is therefore of critical relevance for the timely detection of deleterious immune responses. The identification of relevant immune biomarkers of allo- and autoreactivity has allowed a more accurate monitoring of disease progression and responses to therapy at early stages, allowing proper therapeutic intervention, and possibly improvements in the success rate of islet and pancreas transplantation. This review describes the tools established and validated to monitor immune correlates of auto- and alloreactivity that associate with clinical outcome and identifies challenges that current immunosuppression strategies trying to preserve islet graft function face.


Asunto(s)
Trasplante de Islotes Pancreáticos , Monitorización Inmunológica , Trasplante de Páncreas , Autoinmunidad/inmunología , Diabetes Mellitus Tipo 1/inmunología , Humanos , Memoria Inmunológica/inmunología
11.
Genes Immun ; 14(1): 58-61, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22932817

RESUMEN

The genetic variation causal for predisposition to type 1 diabetes (T1D) remains unidentified for the majority of known T1D risk loci. MicroRNAs function as post-transcriptional gene regulators by targeting microRNA-binding sites in the 3' untranslated regions (UTR) of mRNA. Genetic variation within the 3'-UTR of T1D-associated genes may contribute to T1D development by altering microRNA-mediated gene regulation. In silico analysis of variable sites predicted altered microRNA binding in established T1D loci. Functional implications were assessed for variable sites in the 3'-UTR of T1D candidate risk genes CTLA4 and IL10, both involved in immune regulation. We confirmed that in these genes 3'-UTR variation either disrupted or introduced a microRNA-binding site, affecting the repressive capacity of miR-302a* and miR-523, respectively. Our study points to the potential of 3'-UTR variation to affect T1D pathogenesis by altering post-transcriptional gene regulation by microRNAs.


Asunto(s)
Antígeno CTLA-4/genética , Diabetes Mellitus Tipo 1/genética , Interleucina-10/genética , MicroARNs/metabolismo , Polimorfismo de Nucleótido Simple , Regiones no Traducidas 3'/genética , Sitios de Unión , Antígeno CTLA-4/metabolismo , Regulación de la Expresión Génica , Predisposición Genética a la Enfermedad , Células HEK293 , Humanos , Interleucina-10/metabolismo , MicroARNs/genética
12.
Clin Exp Immunol ; 170(1): 57-65, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22943201

RESUMEN

Beta cells presenting islet epitopes are recognized and destroyed by autoreactive CD8 T cells in type 1 diabetes. These islet-specific T cells are believed to react with epitopes binding with high affinity to human leucocyte antigen (HLA) expressed on beta cells. However, this assumption might be flawed in case of islet autoimmunity. We evaluated T cell recognition of the complete array of preproinsulin (PPI) peptides with regard to HLA binding affinity and T cell recognition. In a comprehensive approach, 203 overlapping 9-10mer PPI peptides were tested for HLA-A2 binding and subjected to binding algorithms. Subsequently, a high-throughput assay was employed to detect PPI-specific T cells in patient blood, in which conditional HLA ligands were destabilized by ultraviolet irradiation and HLA molecules refolded with arrays of PPI peptides, followed by quantum-dot labelling and T cell staining. Analysis of patient blood revealed high frequencies of CD8 T cells recognizing very low HLA binding peptides. Of 28 peptides binding to HLA-A2, a majority was predicted not to bind. Unpredicted peptides bound mainly with low affinities. HLA binding affinity and immunogenicity may not correlate in autoimmunity. Algorithms used to predict high-affinity HLA peptide binders discount the majority of low-affinity HLA binding epitopes. Appreciation that peptides binding HLA with very low affinity can act as targets of autoreactive T cells may help to understand loss of tolerance and disease pathogenesis and possibly point to tissue-specific immune intervention targets.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , Diabetes Mellitus Tipo 1/inmunología , Epítopos de Linfocito T/inmunología , Antígenos de Histocompatibilidad Clase I/inmunología , Insulina/inmunología , Precursores de Proteínas/inmunología , Adolescente , Algoritmos , Secuencia de Aminoácidos , Autoinmunidad/inmunología , Linfocitos T CD8-positivos/metabolismo , Niño , Preescolar , Diabetes Mellitus Tipo 1/metabolismo , Epítopos de Linfocito T/química , Epítopos de Linfocito T/metabolismo , Femenino , Antígeno HLA-A2/inmunología , Antígeno HLA-A2/metabolismo , Antígenos de Histocompatibilidad Clase I/metabolismo , Humanos , Insulina/química , Insulina/metabolismo , Células Secretoras de Insulina/inmunología , Células Secretoras de Insulina/metabolismo , Masculino , Péptidos/análisis , Péptidos/química , Péptidos/inmunología , Péptidos/metabolismo , Unión Proteica , Precursores de Proteínas/química , Precursores de Proteínas/metabolismo
14.
Clin Exp Immunol ; 169(2): 190-8, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22774994

RESUMEN

Transplantation of isolated islet of Langerhans cells has great potential as a cure for type 1 diabetes but continuous immune suppressive therapy often causes considerable side effects. Tapering of immunosuppression in successfully transplanted patients would lower patients' health risk. To identify immune biomarkers that may prove informative in monitoring tapering, we studied the effect of tapering on islet auto- and alloimmune reactivity in a pilot study in five transplant recipients in vitro. Cytokine responses to the graft were measured using Luminex technology. Avidity of alloreactive cytotoxic T Lymphocytes (CTL) was determined by CD8 blockade. The influence of immunosuppression was mimicked by in vitro replenishment of tacrolimus and MPA, the active metabolite of mycophenolate mofetil. Tapering of tacrolimus was generally followed by decreased C-peptide production. T-cell autoreactivity increased in four out of five patients during tapering. Overall alloreactive CTL precursor frequencies did not change, but their avidity to donor mismatches increased significantly after tapering (P = 0·035). In vitro addition of tacrolimus but not MPA strongly inhibited CTL alloreactivity during tapering and led to a significant shift to anti-inflammatory graft-specific cytokine production. Tapering of immunosuppression is characterized by diverse immune profiles that appear to relate inversely to plasma C-peptide levels. Highly avid allospecific CTLs that are known to associate with rejection increased during tapering, but could be countered by restoring immune suppression in vitro. Immune monitoring studies may help guiding tapering of immunosuppression after islet cell transplantation, even though we do not have formal prove yet that the observed changes reflect direct effects of immune suppression on immunity.


Asunto(s)
Terapia de Inmunosupresión , Inmunosupresores/administración & dosificación , Trasplante de Islotes Pancreáticos/inmunología , Islotes Pancreáticos/inmunología , Adulto , Autoinmunidad , Citocinas/biosíntesis , Femenino , Estudios de Seguimiento , Supervivencia de Injerto/efectos de los fármacos , Supervivencia de Injerto/inmunología , Humanos , Inmunidad Celular , Masculino , Persona de Mediana Edad , Proyectos Piloto , Linfocitos T Citotóxicos/inmunología , Trasplante Homólogo
15.
Diabet Med ; 29(6): 734-41, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22150609

RESUMEN

AIMS: The relation of disease progression and age, serum interleukin 10 (IL-10) and interferon gamma (IFNγ) and their genetic correlates were studied in paediatric patients with newly diagnosed Type 1 diabetes. METHODS: Two hundred and twenty-seven patients from the Hvidoere Study Group were classified in four different progression groups as assessed by change in stimulated C-peptide from 1 to 6 months. CA repeat variants of the IL-10 and IFNγ gene were genotyped and serum levels of IL-10 and IFNγ were measured at 1, 6 and 12 months. RESULTS: IL-10 decreased (P < 0.001) by 7.7% (1 month), 10.4% (6 months) and 8.6% (12 months) per year increase in age of child, while a twofold higher C-peptide concentration at 1 month (p = 0.06), 6 months (P = 0.0003) and 12 months (P = 0.02) was associated with 9.7%, 18.6% and 9.7% lower IL-10 levels, independent of each other. IL-10 concentrations did not associate with the disease progression groups. By contrast, IFNγ concentrations differed between the four progression groups at 6 and 12 months (P = 0.02 and P = 0.01, respectively); patients with rapid progressing disease had the highest levels at both time points. Distribution of IL-10 and IFNγ genotypes was equal among patients from the progression groups. CONCLUSION: IL-10 serum levels associate inversely with age and C-peptide. As age and C-peptide also associate, a triangular association is proposed. Genetic influence on IL-10 production seems to be masked by distinct disease mechanisms. Increased serum IFNγ concentrations associate with rapid disease progression. Functional genetic variants do not associate with a single progression pattern group, implying that disease processes override genetically predisposed cytokine production.


Asunto(s)
Envejecimiento/sangre , Péptido C/sangre , Diabetes Mellitus Tipo 1/sangre , Interferón gamma/sangre , Interleucina-10/sangre , Adolescente , Envejecimiento/genética , Biomarcadores/sangre , Péptido C/genética , Niño , Preescolar , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/fisiopatología , Progresión de la Enfermedad , Ayuno , Femenino , Predisposición Genética a la Enfermedad , Humanos , Lactante , Interferón gamma/genética , Interleucina-10/genética , Masculino
16.
Diabetologia ; 54(12): 3062-70, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21909837

RESUMEN

AIMS/HYPOTHESIS: Natural killer (NK) cells serve as primary immune surveillance and are partially regulated by combinations of killer immunoglobulin-like receptor (KIR) genes and their HLA class I ligands. Alterations in NK cell activity have been associated with type 1 diabetes. The aim of this study was to determine whether KIR-HLA class I gene frequency: (1) is altered in a current population with type 1 diabetes compared with healthy controls; and (2) has changed over the half century in which the incidence of type 1 diabetes has increased rapidly. METHODS: KIR-HLA class I gene frequencies were compared in 551 individuals diagnosed with type 1 diabetes ≤ 15 years of age (394 in a current cohort and 157 from the historical 'Golden Years' cohort) and 168 healthy controls. The overall balance of activation and inhibition was analysed using KIR-HLA genotype models. RESULTS: Children with type 1 diabetes who were positive for KIR2DS2/KIR2DL2 and KIR2DL3 were more often homozygous for HLA-C group 1 and this effect was strongest in children diagnosed with diabetes before the age of 5 years (p = 0.003, corrected p [p (corr)] = 0.012) and (p = 0.001, p (corr) = 0.004), respectively. Children with type 1 diabetes have fewer inhibitory KIRs with their corresponding ligands compared with healthy controls (p = 1.9 × 10(-4)). This pattern of NK activation has not changed significantly in individuals with type 1 diabetes over the last half century. CONCLUSIONS/INTERPRETATION: Activating combinations of KIR-HLA genes are more frequent in young children with type 1 diabetes diagnosed in the first 5 years of life, suggesting that NK cell responses may be altered in this group.


Asunto(s)
Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/inmunología , Antígenos HLA-C/genética , Antígenos HLA-C/inmunología , Receptores de Células Asesinas Naturales/genética , Receptores de Células Asesinas Naturales/inmunología , Adolescente , Edad de Inicio , Niño , Preescolar , Estudios de Cohortes , Femenino , Frecuencia de los Genes/genética , Frecuencia de los Genes/inmunología , Homocigoto , Humanos , Lactante , Células Asesinas Naturales/inmunología , Masculino
17.
Genes Immun ; 12(6): 415-27, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21562577

RESUMEN

Human leukocyte antigen (HLA) class II haplotypes are established risk factors in type 1 diabetes (T1D). The heterozygous DQ2/8 genotype confers the highest risk, whereas the DQ6/8 genotype is protective. We hypothesized that DQ2/8 trans-molecules composed of α and ß chains from DQ2 and DQ8 express unique ß-cell epitopes, whereas DQ6 may interfere with peptide binding to DQ8. Here we show that a single insulin epitope (InsB13-21) within the T1D prototype antigenic InsB6-22 peptide can bind to both cis- and trans-dimers, although these molecules display different peptide binding patterns. DQ6 binds a distinct insulin epitope (InsB6-14). The phenotype of DQ8-restricted T cells from a T1D patient changed from proinflammatory to anti-inflammatory in the presence of DQ6. Our data provide new insights into both susceptible and protective mechanism of DQ, where protecting HLA molecules bind autoantigens in a different (competing) binding register leading to 'epitope stealing', thereby inducing a regulatory, rather than a pathogenic immune response.


Asunto(s)
Diabetes Mellitus Tipo 1/metabolismo , Antígenos HLA-DQ/genética , Islotes Pancreáticos/inmunología , Adolescente , Linfocitos B/citología , Linfocitos B/inmunología , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/inmunología , Epítopos de Linfocito B/inmunología , Predisposición Genética a la Enfermedad , Heterocigoto , Homocigoto , Humanos , Insulina/genética , Masculino , Unión Proteica , Sindecanos/metabolismo , Linfocitos T/citología , Linfocitos T/inmunología , Timosina/metabolismo
18.
Tissue Antigens ; 77(4): 338-40, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21388358

RESUMEN

An extreme genetic risk for type 1 diabetes (T1D) was reported for DR3/4-DQ8 siblings sharing both extended human leukocyte antigen (HLA) haplotypes identical-by-descent (IBD) with their diabetic proband. We attempted to replicate this finding in our prospective Dutch T1D cohort and in families from the Type 1 Diabetes Genetics Consortium (T1DGC). Only 2 of the 14 Dutch siblings, sharing both DR3-DQ2/DR4-DQ8 haplotypes IBD with their diabetic proband, developed T1D in a 12-year follow-up period. No differential sharing of HLA haplotypes or significant transmission distortion in parents homozygous for HLA risk alleles was found in T1DGC material. Therefore, we could not confirm the reported extreme risk for T1D, suggesting that the risk conferred by other HLA complex loci is moderate.


Asunto(s)
Alelos , Diabetes Mellitus Tipo 1/genética , Antígeno HLA-DR3/genética , Antígeno HLA-DR4/genética , Hermanos , Adolescente , Niño , Estudios de Cohortes , Femenino , Predisposición Genética a la Enfermedad , Antígenos HLA-DQ , Haplotipos , Humanos , Masculino , Países Bajos , Factores de Riesgo
19.
Cancer Immunol Immunother ; 60(1): 15-22, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21080166

RESUMEN

Many assays to evaluate the nature, breadth, and quality of antigen-specific T cell responses are currently applied in human medicine. In most cases, assay-related protocols are developed on an individual laboratory basis, resulting in a large number of different protocols being applied worldwide. Together with the inherent complexity of cellular assays, this leads to unnecessary limitations in the ability to compare results generated across institutions. Over the past few years a number of critical assay parameters have been identified which influence test performance irrespective of protocol, material, and reagents used. Describing these critical factors as an integral part of any published report will both facilitate the comparison of data generated across institutions and lead to improvements in the assays themselves. To this end, the Minimal Information About T Cell Assays (MIATA) project was initiated. The objective of MIATA is to achieve a broad consensus on which T cell assay parameters should be reported in scientific publications and to propose a mechanism for reporting these in a systematic manner. To add maximum value for the scientific community, a step-wise, open, and field-spanning approach has been taken to achieve technical precision, user-friendliness, adequate incorporation of concerns, and high acceptance among peers. Here, we describe the past, present, and future perspectives of the MIATA project. We suggest that the approach taken can be generically applied to projects in which a broad consensus has to be reached among scientists working in fragmented fields, such as immunology. An additional objective of this undertaking is to engage the broader scientific community to comment on MIATA and to become an active participant in the project.


Asunto(s)
Consenso , Neoplasias/inmunología , Linfocitos T/inmunología , Alergia e Inmunología/tendencias , Humanos , Técnicas Inmunológicas/normas , Monitoreo Fisiológico/normas , Guías de Práctica Clínica como Asunto , Desarrollo de Programa , Proyectos de Investigación
20.
Clin Exp Immunol ; 161(3): 444-52, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20529086

RESUMEN

The progression of type 1 diabetes after diagnosis is poorly understood. Our aim was to assess the relation of disease progression of juvenile-onset type 1 diabetes, determined by preserved beta cell function the first year after diagnosis, with systemic cytokine concentrations and number of autoantibodies. Juvenile patients (n = 227) had a meal-stimulated C-peptide test 1 and 6 months after diagnosis. On the basis of the C-peptide course for the duration of 1-6 months, four progression groups were defined: patients with persistently low beta cell function ('stable-low'), rapid progressers, slow progressers and remitters. Serum concentrations of adiponectin, interleukin (IL)-1ra, inducible protein 10 (IP-10), IL-6 and glutamic acid decarboxylase (GAD), IA-2A and islet-cell antibodies (ICA) were measured at 1, 6 and 12 months. We found that adiponectin concentrations at 1 month predicted disease progression at 6 months (P = 0·04). Patients with low adiponectin had a higher probability of becoming remitters than rapid progressers, odds ratio 3·1 (1·3-7·6). At 6 and 12 months, adiponectin differed significantly between the groups, with highest concentrations among stable-low and rapid progressers patients (P = 0·03 and P = 0·006). IL-1ra, IP-10 and IL-6 did not differ between the groups at any time-point. The number of autoantibodies differed significantly between the groups at 1 month (P = 0·04), where rapid progressers had the largest number. There was no difference between the groups in human leucocyte antigen-associated risk. We define progression patterns distinguishing patients diagnosed with low beta cell function from those with rapid decline, slow decline or actual increase in beta cell function, pointing to different mechanisms of disease progression. We find that adiponectin concentration at 1 month predicts, and at 6 and 12 months associates with, distinct progression patterns.


Asunto(s)
Adiponectina/sangre , Autoanticuerpos/sangre , Quimiocina CXCL10/sangre , Diabetes Mellitus Tipo 1/sangre , Proteína Antagonista del Receptor de Interleucina 1/sangre , Interleucina-6/sangre , Adolescente , Péptido C/sangre , Niño , Preescolar , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/inmunología , Progresión de la Enfermedad , Femenino , Humanos , Lactante , Masculino , Valor Predictivo de las Pruebas , Estudios Prospectivos , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...