Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 109
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Immunology ; 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31880316

RESUMO

SLAMF9 is an orphan receptor of the CD2/SLAM family of leucocyte surface proteins. Examination of SLAMF9 expression and function indicates that SLAMF9 promotes inflammation by specialized subsets of antigen presenting cells. Within healthy liver and circulating mouse PBMCs, SLAMF9 is expressed on CD11b+, Ly6C-, CD11clow , F4/80low , MHC-II+, CX3 CR1+ mononuclear phagocytes as well as plasmacytoid dendritic cells. In addition, SLAMF9 can be found on peritoneal B1 cells and small (F4/80low ), but not large (F4/80high ), peritoneal macrophages. Upon systemic challenge with Salmonella enterica Typhimurium, Slamf9-/- mice were impaired in their ability to clear the infection from the liver. In humans, SLAMF9 is up-regulated upon differentiation of monocytes into macrophages, and LPS stimulation of PMA-differentiated, SLAMF9 knockdown THP-1 cells showed an essential role of SLAMF9 in production of GM-CSF, TNFα, and IL-1ß. Taken together, these data implicate SLAMF9 in the initiation of inflammation and clearance of bacterial infection.

2.
Nat Commun ; 10(1): 5120, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31719529

RESUMO

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare inflammatory disease of unknown cause. 30% of patients have anti-neutrophil cytoplasmic antibodies (ANCA) specific for myeloperoxidase (MPO). Here, we describe a genome-wide association study in 676 EGPA cases and 6809 controls, that identifies 4 EGPA-associated loci through conventional case-control analysis, and 4 additional associations through a conditional false discovery rate approach. Many variants are also associated with asthma and six are associated with eosinophil count in the general population. Through Mendelian randomisation, we show that a primary tendency to eosinophilia contributes to EGPA susceptibility. Stratification by ANCA reveals that EGPA comprises two genetically and clinically distinct syndromes. MPO+ ANCA EGPA is an eosinophilic autoimmune disease sharing certain clinical features and an HLA-DQ association with MPO+ ANCA-associated vasculitis, while ANCA-negative EGPA may instead have a mucosal/barrier dysfunction origin. Four candidate genes are targets of therapies in development, supporting their exploration in EGPA.

3.
J Exp Med ; 216(9): 1986-1998, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31235509

RESUMO

IL-6 excess is central to the pathogenesis of multiple inflammatory conditions and is targeted in clinical practice by immunotherapy that blocks the IL-6 receptor encoded by IL6R We describe two patients with homozygous mutations in IL6R who presented with recurrent infections, abnormal acute-phase responses, elevated IgE, eczema, and eosinophilia. This study identifies a novel primary immunodeficiency, clarifying the contribution of IL-6 to the phenotype of patients with mutations in IL6ST, STAT3, and ZNF341, genes encoding different components of the IL-6 signaling pathway, and alerts us to the potential toxicity of drugs targeting the IL-6R.

4.
Arterioscler Thromb Vasc Biol ; 39(7): 1379-1389, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31092015

RESUMO

Objective- Investigate the impact of modulating B cell FcγRIIb (Fcγ receptor IIb) expression on atherosclerosis. Approach and Results- Western diet-induced atherosclerosis was assessed in Ldlr-/- or Apoe-/- mice with B cell-specific overexpression of FcγRIIb or with an FcγRIIb promoter mutation that alters FcγRIIb expression in germinal center (GC) B cells. In males, overexpression of FcγRIIb on B cells severely reduced activated, class switched B cell responses, as indicated by reductions in GC B cells, plasma cells, and serum IgG but not IgM antibodies. Male mice overexpressing FcγRIIb developed less atherosclerosis, suggesting a pathogenic role for GC B cell IgG responses. In support of this hypothesis, male mice with a promoter polymorphism-driven reduction in FcγRIIb on GC B cells but not plasma cells have a converse phenotype of enhanced GC responses and IgG2c antibodies and enhanced atherosclerosis. IgG2c significantly enhanced TNF (tumor necrosis factor) secretion by CD11b+ CD11c+ cells expressing the high-affinity receptor FcγRIV. In females, overexpression of FcγRIIb on B cells not only reduced GC B cell responses but also substantially reduced B-1 cells and IgM antibodies, which translated into acceleration of atherosclerosis. Promoter-driven reduction in FcγRIIb did not alter GC B cell responses in females and, therefore, had no impact on atherosclerosis. Conclusions- B cell FcγRIIb differentially alters proatherogenic adaptive GC B cell and atheroprotective innate B-1 responses in male and female mice fed a western diet. Our results highlight the importance of a better understanding and ability to selectively target B cell responses in future immunotherapeutic approaches against human cardiovascular disease. Visual Overview- An online visual overview is available for this article.

5.
Science ; 364(6442)2019 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-31123110

RESUMO

Approximately 2.4% of the human mitochondrial DNA (mtDNA) genome exhibits common homoplasmic genetic variation. We analyzed 12,975 whole-genome sequences to show that 45.1% of individuals from 1526 mother-offspring pairs harbor a mixed population of mtDNA (heteroplasmy), but the propensity for maternal transmission differs across the mitochondrial genome. Over one generation, we observed selection both for and against variants in specific genomic regions; known variants were more likely to be transmitted than previously unknown variants. However, new heteroplasmies were more likely to match the nuclear genetic ancestry as opposed to the ancestry of the mitochondrial genome on which the mutations occurred, validating our findings in 40,325 individuals. Thus, human mtDNA at the population level is shaped by selective forces within the female germ line under nuclear genetic control, which ensures consistency between the two independent genetic lineages.

6.
Nat Commun ; 10(1): 1970, 2019 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-31036800

RESUMO

Several tolerance checkpoints exist throughout B cell development to control autoreactive B cells and prevent the generation of pathogenic autoantibodies. FcγRIIb is an Fc receptor that inhibits B cell activation and, if defective, is associated with autoimmune disease, yet its impact on specific B cell tolerance checkpoints is unknown. Here we show that reduced expression of FcγRIIb enhances the deletion and anergy of autoreactive immature B cells, but in contrast promotes autoreactive B cell expansion in the germinal center and serum autoantibody production, even in response to exogenous, non-self antigens. Our data thus show that FcγRIIb has opposing effects on pre-immune and post-immune tolerance checkpoints, and suggest that B cell tolerance requires the control of bystander germinal center B cells with low or no affinity for the immunizing antigen.


Assuntos
Linfócitos B/imunologia , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Tolerância Imunológica/imunologia , Receptores de IgG/metabolismo , Algoritmos , Animais , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Centro Germinativo , Humanos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Masculino , Camundongos , Receptores de IgG/genética , Software
7.
J Exp Med ; 216(6): 1311-1327, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31040185

RESUMO

Interleukin-2, which conveys essential signals for immunity, operates through a heterotrimeric receptor. Here we identify human interleukin-2 receptor (IL-2R) ß chain (IL2RB) gene defects as a cause of life-threatening immune dysregulation. We report three homozygous mutations in the IL2RB gene of eight individuals from four consanguineous families that cause disease by distinct mechanisms. Nearly all patients presented with autoantibodies, hypergammaglobulinemia, bowel inflammation, dermatological abnormalities, lymphadenopathy, and cytomegalovirus disease. Patient T lymphocytes lacked surface expression of IL-2Rß and were unable to respond to IL-2 stimulation. By contrast, natural killer cells retained partial IL-2Rß expression and function. IL-2Rß loss of function was recapitulated in a recombinant system in which IL2RB mutations caused reduced surface expression and IL-2 binding. Stem cell transplant ameliorated clinical symptoms in one patient; forced expression of wild-type IL-2Rß also increased the IL-2 responsiveness of patient T lymphocytes in vitro. Insights from these patients can inform the development of IL-2-based therapeutics for immunological diseases and cancer.

8.
Gut ; 68(8): 1386-1395, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31030191

RESUMO

OBJECTIVE: We have previously described a prognostic transcriptional signature in CD8 T cells that separates patients with IBD into two phenotypically distinct subgroups, termed IBD1 and IBD2. Here we sought to develop a blood-based test that could identify these subgroups without cell separation, and thus be suitable for clinical use in Crohn's disease (CD) and ulcerative colitis (UC). DESIGN: Patients with active IBD were recruited before treatment. Transcriptomic analyses were performed on purified CD8 T cells and/or whole blood. Phenotype data were collected prospectively. IBD1/IBD2 patient subgroups were identified by consensus clustering of CD8 T cell transcriptomes. In a training cohort, machine learning was used to identify groups of genes ('classifiers') whose differential expression in whole blood recreated the IBD1/IBD2 subgroups. Genes from the best classifiers were quantitative (q)PCR optimised, and further machine learning was used to identify the optimal qPCR classifier, which was locked down for further testing. Independent validation was sought in separate cohorts of patients with CD (n=66) and UC (n=57). RESULTS: In both validation cohorts, a 17-gene qPCR-based classifier stratified patients into two distinct subgroups. Irrespective of the underlying diagnosis, IBDhi patients (analogous to the poor prognosis IBD1 subgroup) experienced significantly more aggressive disease than IBDlo patients (analogous to IBD2), with earlier need for treatment escalation (hazard ratio=2.65 (CD), 3.12 (UC)) and more escalations over time (for multiple escalations within 18 months: sensitivity=72.7% (CD), 100% (UC); negative predictive value=90.9% (CD), 100% (UC)). CONCLUSION: This is the first validated prognostic biomarker that can predict prognosis in newly diagnosed patients with IBD and represents a step towards personalised therapy.


Assuntos
Linfócitos T CD8-Positivos/metabolismo , Colite Ulcerativa , Doença de Crohn , Adulto , Biomarcadores/sangue , Colite Ulcerativa/sangue , Colite Ulcerativa/diagnóstico , Doença de Crohn/sangue , Doença de Crohn/diagnóstico , Diagnóstico Diferencial , Feminino , Expressão Gênica , Perfilação da Expressão Gênica/métodos , Humanos , Aprendizado de Máquina , Masculino , Pessoa de Meia-Idade , Fenótipo , Valor Preditivo dos Testes , Prognóstico , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Índice de Gravidade de Doença
10.
BMJ Open ; 8(12): e026767, 2018 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-30523133

RESUMO

BACKGROUND: The course of Crohn's disease (CD) varies substantially between individuals, but reliable prognostic markers do not exist. This hinders disease management because patients with aggressive disease are undertreated by conventional 'step-up' therapy (in which treatment is gradually escalated in response to refractory or relapsing disease) while those with more indolent disease would be exposed to unnecessary treatment-related toxicity if a more aggressive 'top-down' approach was indiscriminately used. The Predicting outcomes for Crohn's disease using a molecular biomarker trial will assess whether a prognostic transcriptional biomarker, that we have developed and validated, can improve clinical outcomes by facilitating personalised therapy in CD. This represents the first the biomarker-stratified trial in inflammatory bowel disease. METHODS AND ANALYSIS: This biomarker-stratified trial will compare the relative efficacy of 'top-down' and 'accelerated step-up' therapy between biomarker-defined subgroups of patients with newly diagnosed CD. 400 participants from ~50 UK centres will be recruited. Subjects within each biomarker subgroup (IBDhi or IBDlo) will be randomised (1:1) to receive one of the treatment strategies until trial completion (48 weeks). The primary outcome is the incidence of sustained surgery and steroid-free remission from the completion of induction treatment through to week 48. Secondary outcomes include mucosal healing, quality-of-life assessments and surrogate measures of disease burden including number of flares, cumulative steroid exposure, number of hospital admissions and number of Crohn's-related surgeries (assessed hierarchically). Analyses will compare the relative benefit of the treatment strategies in each biomarker-defined subgroup, powered as an interaction analysis, to determine whether the biomarker can accurately match patients to the most appropriate therapy. ETHICS AND DISSEMINATION: Ethical approval has been obtained and recruitment is under way at sites around the UK. Following trial completion and data analysis, the results of the trial will be submitted for publication in peer-reviewed journals and presented at international conferences. TRIAL REGISTRATION NUMBER: ISRCTN11808228; Pre-results.


Assuntos
Doença de Crohn/diagnóstico , Doença de Crohn/tratamento farmacológico , Marcadores Genéticos , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Anti-Inflamatórios/uso terapêutico , Humanos , Estudos Multicêntricos como Assunto , Prognóstico , Ensaios Clínicos Controlados Aleatórios como Assunto , Indução de Remissão
11.
PLoS Genet ; 14(9): e1007458, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30199539

RESUMO

Chronic inflammation in inflammatory bowel disease (IBD) results from a breakdown of intestinal immune homeostasis and compromise of the intestinal barrier. Genome-wide association studies have identified over 200 genetic loci associated with risk for IBD, but the functional mechanisms of most of these genetic variants remain unknown. Polymorphisms at the TNFSF15 locus, which encodes the TNF superfamily cytokine commonly known as TL1A, are associated with susceptibility to IBD in multiple ethnic groups. In a wide variety of murine models of inflammation including models of IBD, TNFSF15 promotes immunopathology by signaling through its receptor DR3. Such evidence has led to the hypothesis that expression of this lymphocyte costimulatory cytokine increases risk for IBD. In contrast, here we show that the IBD-risk haplotype at TNFSF15 is associated with decreased expression of the gene by peripheral blood monocytes in both healthy volunteers and IBD patients. This association persists under various stimulation conditions at both the RNA and protein levels and is maintained after macrophage differentiation. Utilizing a "recall-by-genotype" bioresource for allele-specific expression measurements in a functional fine-mapping assay, we localize the polymorphism controlling TNFSF15 expression to the regulatory region upstream of the gene. Through a T cell costimulation assay, we demonstrate that genetically regulated TNFSF15 has functional relevance. These findings indicate that genetically enhanced expression of TNFSF15 in specific cell types may confer protection against the development of IBD.


Assuntos
Colite Ulcerativa/genética , Doença de Crohn/genética , Predisposição Genética para Doença , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/metabolismo , Adulto , Alelos , Células Cultivadas , Colite Ulcerativa/sangue , Colite Ulcerativa/imunologia , Doença de Crohn/sangue , Doença de Crohn/imunologia , Feminino , Haplótipos/genética , Humanos , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Pessoa de Meia-Idade , Monócitos/imunologia , Monócitos/metabolismo , Polimorfismo de Nucleotídeo Único/genética , Cultura Primária de Células , Locos de Características Quantitativas/imunologia , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/sangue , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/genética , Adulto Jovem
12.
Front Immunol ; 9: 1784, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30147686

RESUMO

A diverse B-cell receptor (BCR) repertoire is required to bind a wide range of antigens. BCRs are generated through genetic recombination and can be diversified through somatic hypermutation (SHM) or class-switch recombination (CSR). Patterns of repertoire diversity can vary substantially between different health conditions. We use isotype-resolved BCR sequencing to compare B-cell evolution and class-switch fate in healthy individuals and in patients with chronic lymphocytic leukemia (CLL). We show that the patterns of SHM and CSR in B-cells from healthy individuals are distinct from CLL. We identify distinct properties of clonal expansion that lead to the generation of antibodies of different classes in healthy, malignant, and non-malignant CLL BCR repertoires. We further demonstrate that BCR diversity is affected by relationships between antibody variable and constant regions leading to isotype-specific signatures of variable gene usage. This study provides powerful insights into the mechanisms underlying the evolution of the adaptive immune responses in health and their aberration during disease.


Assuntos
Linfócitos B/metabolismo , Rearranjo Gênico do Linfócito B , Switching de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/genética , Receptores de Antígenos de Linfócitos B/genética , Hipermutação Somática de Imunoglobulina , Linfócitos B/imunologia , Linfócitos B/patologia , Humanos , Isotipos de Imunoglobulinas/genética , Região de Junção de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/imunologia , Leucemia Linfocítica Crônica de Células B/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/patologia , Família Multigênica
13.
Lancet ; 391(10140): 2619-2630, 2018 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-29910042

RESUMO

BACKGROUND: B cells produce alloantibodies and activate alloreactive T cells, negatively affecting kidney transplant survival. By contrast, regulatory B cells are associated with transplant tolerance. Immunotherapies are needed that inhibit B-cell effector function, including antibody secretion, while sparing regulators and minimising infection risk. B lymphocyte stimulator (BLyS) is a cytokine that promotes B-cell activation and has not previously been targeted in kidney transplant recipients. We aimed to determine the safety and activity of an anti-BLyS antibody, belimumab, in addition to standard-of-care immunosuppression in adult kidney transplant recipients. We used an experimental medicine study design with multiple secondary and exploratory endpoints to gain further insight into the effect of belimumab on the generation of de-novo IgG and on the regulatory B-cell compartment. METHODS: We undertook a double-blind, randomised, placebo-controlled phase 2 trial of belimumab, in addition to standard-of-care immunosuppression (basiliximab, mycophenolate mofetil, tacrolimus, and prednisolone) at two centres, Addenbrooke's Hospital, Cambridge, UK, and Guy's and St Thomas' Hospital, London, UK. Participants were eligible if they were aged 18-75 years and receiving a kidney transplant and were planned to receive standard-of-care immunosuppression. Participants were randomly assigned (1:1) to receive either intravenous belimumab 10 mg per kg bodyweight or placebo, given at day 0, 14, and 28, and then every 4 weeks for a total of seven infusions. The co-primary endpoints were safety and change in the concentration of naive B cells from baseline to week 24, both of which were analysed in all patients who received a transplant and at least one dose of drug or placebo (the modified intention-to-treat [mITT] population). This trial has been completed and is registered with ClinicalTrials.gov, NCT01536379, and EudraCT, 2011-006215-56. FINDINGS: Between Sept 13, 2013, and Feb 8, 2015, of 303 patients assessed for eligibility, 28 kidney transplant recipients were randomly assigned to receive belimumab (n=14) or placebo (n=14). 25 patients (12 [86%] patients assigned to the belimumab group and 13 [93%] patients assigned to the placebo group) received a transplant and were included in the mITT population. We observed similar proportions of adverse events in the belimumab and placebo groups, including serious infections (one [8%] of 12 in the belimumab group and five [38%] of 13 in the placebo group during the 6-month on-treatment phase; and none in the belimumab group and two [15%] in the placebo group during the 6-month follow-up). In the on-treatment phase, one patient in the placebo group died because of fatal myocardial infarction and acute cardiac failure. The co-primary endpoint of a reduction in naive B cells from baseline to week 24 was not met. Treatment with belimumab did not significantly reduce the number of naive B cells from baseline to week 24 (adjusted mean difference between the belimumab and placebo treatment groups -34·4 cells per µL, 95% CI -109·5 to 40·7). INTERPRETATION: Belimumab might be a useful adjunct to standard-of-care immunosuppression in renal transplantation, with no major increased risk of infection and potential beneficial effects on humoral alloimmunity. FUNDING: GlaxoSmithKline.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Sobrevivência de Enxerto/efeitos dos fármacos , Imunossupressão/métodos , Imunossupressores/administração & dosagem , Transplante de Rim/métodos , Administração Intravenosa , Adulto , Idoso , Método Duplo-Cego , Feminino , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade
14.
Immunology ; 155(1): 3-17, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29574826

RESUMO

High-throughput sequencing of the DNA/RNA encoding antibody heavy- and light-chains is rapidly transforming the field of adaptive immunity. It can address key questions, including: (i) how the B-cell repertoire differs in health and disease; and (ii) if it does differ, the point(s) in B-cell development at which this occurs. The advent of technologies, such as whole-genome sequencing, offers the chance to link abnormalities in the B-cell antibody repertoire to specific genomic variants and polymorphisms. Here, we discuss the current research using B-cell antibody repertoire sequencing in three polygenic autoimmune diseases where there is good evidence for a pathological role for B-cells, namely systemic lupus erythematosus, multiple sclerosis and rheumatoid arthritis. These autoimmune diseases exhibit significantly skewed B-cell receptor repertoires compared with healthy controls. Interestingly, some common repertoire defects are shared between diseases, such as elevated IGHV4-34 gene usage. B-cell clones have effectively been characterized and tracked between different tissues and blood in autoimmune disease. It has been hypothesized that these differences may signify differences in B-cell tolerance; however, the mechanisms and implications of these defects are not clear.


Assuntos
Anticorpos/imunologia , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Herança Multifatorial/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos
15.
J Allergy Clin Immunol ; 142(4): 1285-1296, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29477724

RESUMO

BACKGROUND: The genetic cause of primary immunodeficiency disease (PID) carries prognostic information. OBJECTIVE: We conducted a whole-genome sequencing study assessing a large proportion of the NIHR BioResource-Rare Diseases cohort. METHODS: In the predominantly European study population of principally sporadic unrelated PID cases (n = 846), a novel Bayesian method identified nuclear factor κB subunit 1 (NFKB1) as one of the genes most strongly associated with PID, and the association was explained by 16 novel heterozygous truncating, missense, and gene deletion variants. This accounted for 4% of common variable immunodeficiency (CVID) cases (n = 390) in the cohort. Amino acid substitutions predicted to be pathogenic were assessed by means of analysis of structural protein data. Immunophenotyping, immunoblotting, and ex vivo stimulation of lymphocytes determined the functional effects of these variants. Detailed clinical and pedigree information was collected for genotype-phenotype cosegregation analyses. RESULTS: Both sporadic and familial cases demonstrated evidence of the noninfective complications of CVID, including massive lymphadenopathy (24%), unexplained splenomegaly (48%), and autoimmune disease (48%), features prior studies correlated with worse clinical prognosis. Although partial penetrance of clinical symptoms was noted in certain pedigrees, all carriers have a deficiency in B-lymphocyte differentiation. Detailed assessment of B-lymphocyte numbers, phenotype, and function identifies the presence of an increased CD21low B-cell population. Combined with identification of the disease-causing variant, this distinguishes between healthy subjects, asymptomatic carriers, and clinically affected cases. CONCLUSION: We show that heterozygous loss-of-function variants in NFKB1 are the most common known monogenic cause of CVID, which results in a temporally progressive defect in the formation of immunoglobulin-producing B cells.


Assuntos
Linfócitos B/imunologia , Imunodeficiência de Variável Comum/genética , Subunidade p50 de NF-kappa B/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Europa (Continente) , Feminino , Humanos , Lactente , Recém-Nascido , Mutação com Perda de Função , Masculino , Pessoa de Meia-Idade , Fenótipo , Linfócitos T/imunologia , Adulto Jovem
16.
Ann Rheum Dis ; 77(4): 589-595, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29374629

RESUMO

OBJETIVE: Systemic vasculitides represent a heterogeneous group of rare complex diseases of the blood vessels with a poorly understood aetiology. To investigate the shared genetic component underlying their predisposition, we performed the first cross-phenotype meta-analysis of genetic data from different clinically distinct patterns of vasculitis. METHODS: Immunochip genotyping data from 2465 patients diagnosed with giant cell arteritis, Takayasu's arteritis, antineutrophil cytoplasmic antibody-associated vasculitis or IgA vasculitis as well as 4632 unaffected controls were analysed to identify common susceptibility loci for vasculitis development. The possible functional consequences of the associated variants were interrogated using publicly available annotation data. RESULTS: The strongest association signal corresponded with an intergenic polymorphism located between HLA-DQB1 and HLA-DQA2 (rs6932517, P=4.16E-14, OR=0.74). This single nucleotide polymorphism is in moderate linkage disequilibrium with the disease-specific human leucocyte antigen (HLA) class II associations of each type of vasculitis and could mark them. Outside the HLA region, we identified the KDM4C gene as a common risk locus for vasculitides (highest peak rs16925200, P=6.23E-07, OR=1.75). This gene encodes a histone demethylase involved in the epigenetic control of gene expression. CONCLUSIONS: Through a combined analysis of Immunochip data, we have identified KDM4C as a new risk gene shared between systemic vasculitides, consistent with the increasing evidences of the crucial role that the epigenetic mechanisms have in the development of complex immune-mediated conditions.


Assuntos
Loci Gênicos/genética , Histona Desmetilases com o Domínio Jumonji/genética , Fenótipo , Vasculite Sistêmica/genética , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/genética , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/imunologia , Estudos de Casos e Controles , Epigênese Genética , Feminino , Loci Gênicos/imunologia , Predisposição Genética para Doença , Arterite de Células Gigantes/genética , Arterite de Células Gigantes/imunologia , Antígenos HLA-DQ/genética , Antígenos HLA-DQ/imunologia , Cadeias beta de HLA-DQ/genética , Cadeias beta de HLA-DQ/imunologia , Humanos , Histona Desmetilases com o Domínio Jumonji/imunologia , Desequilíbrio de Ligação , Masculino , Polimorfismo de Nucleotídeo Único , Análise Serial de Proteínas , Vasculite Sistêmica/imunologia , Arterite de Takayasu/genética , Arterite de Takayasu/imunologia
17.
J Exp Med ; 214(4): 1111-1128, 2017 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-28351984

RESUMO

The phagocyte respiratory burst is crucial for innate immunity. The transfer of electrons to oxygen is mediated by a membrane-bound heterodimer, comprising gp91phox and p22phox subunits. Deficiency of either subunit leads to severe immunodeficiency. We describe Eros (essential for reactive oxygen species), a protein encoded by the previously undefined mouse gene bc017643, and show that it is essential for host defense via the phagocyte NAPDH oxidase. Eros is required for expression of the NADPH oxidase components, gp91phox and p22phox Consequently, Eros-deficient mice quickly succumb to infection. Eros also contributes to the formation of neutrophil extracellular traps (NETS) and impacts on the immune response to melanoma metastases. Eros is an ortholog of the plant protein Ycf4, which is necessary for expression of proteins of the photosynthetic photosystem 1 complex, itself also an NADPH oxio-reductase. We thus describe the key role of the previously uncharacterized protein Eros in host defense.


Assuntos
Proteínas de Membrana/fisiologia , Fagócitos/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Explosão Respiratória/fisiologia , Animais , Grupo dos Citocromos b/análise , Grupo dos Citocromos b/fisiologia , Retículo Endoplasmático/metabolismo , Células HEK293 , Humanos , Imunidade Inata , Macrófagos/imunologia , Glicoproteínas de Membrana/análise , Glicoproteínas de Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , NADPH Oxidase 2 , NADPH Oxidases/análise , NADPH Oxidases/fisiologia , Neutrófilos/imunologia , Fagocitose
18.
Nat Genet ; 49(2): 262-268, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28067912

RESUMO

For most immune-mediated diseases, the main determinant of patient well-being is not the diagnosis itself but instead the course that the disease takes over time (prognosis). Prognosis may vary substantially between patients for reasons that are poorly understood. Familial studies support a genetic contribution to prognosis, but little evidence has been found for a proposed association between prognosis and the burden of susceptibility variants. To better characterize how genetic variation influences disease prognosis, we performed a within-cases genome-wide association study in two cohorts of patients with Crohn's disease. We identified four genome-wide significant loci, none of which showed any association with disease susceptibility. Conversely, the aggregated effect of all 170 disease susceptibility loci was not associated with disease prognosis. Together, these data suggest that the genetic contribution to prognosis in Crohn's disease is largely independent of the contribution to disease susceptibility and point to a biology of prognosis that could provide new therapeutic opportunities.


Assuntos
Doença de Crohn/genética , Predisposição Genética para Doença/genética , Feminino , Genoma/genética , Estudo de Associação Genômica Ampla/métodos , Genótipo , Humanos , Masculino , Polimorfismo de Nucleotídeo Único/genética , Prognóstico
20.
Genome Med ; 8(1): 76, 2016 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-27435189

RESUMO

BACKGROUND: Tumour necrosis factor (TNF) superfamily cytokines and their receptors regulate diverse immune system functions through a common set of signalling pathways. Genetic variants in and expression of individual TNF superfamily cytokines, receptors and signalling proteins have been associated with autoimmune and inflammatory diseases, but their interconnected biology has been largely unexplored. METHODS: We took a hypothesis-driven approach using available genome-wide datasets to identify genetic variants regulating gene expression in the TNF superfamily cytokine signalling network and the association of these variants with autoimmune and autoinflammatory disease. Using paired gene expression and genetic data, we identified genetic variants associated with gene expression, expression quantitative trait loci (eQTLs), in four peripheral blood cell subsets. We then examined whether eQTLs were dependent on gene expression level or the presence of active enhancer chromatin marks. Using these eQTLs as genetic markers of the TNF superfamily signalling network, we performed targeted gene set association analysis in eight autoimmune and autoinflammatory disease genome-wide association studies. RESULTS: Comparison of TNF superfamily network gene expression and regulatory variants across four leucocyte subsets revealed patterns that differed between cell types. eQTLs for genes in this network were not dependent on absolute gene expression levels and were not enriched for chromatin marks of active enhancers. By examining autoimmune disease risk variants among our eQTLs, we found that risk alleles can be associated with either increased or decreased expression of co-stimulatory TNF superfamily cytokines, receptors or downstream signalling molecules. Gene set disease association analysis revealed that eQTLs for genes in the TNF superfamily pathway were associated with six of the eight autoimmune and autoinflammatory diseases examined, demonstrating associations beyond single genome-wide significant hits. CONCLUSIONS: This systematic analysis of the influence of regulatory genetic variants in the TNF superfamily network reveals widespread and diverse roles for these cytokines in susceptibility to a number of immune-mediated diseases.


Assuntos
Doenças Autoimunes/genética , Predisposição Genética para Doença , Doenças Hereditárias Autoinflamatórias/genética , Locos de Características Quantitativas , Receptores do Fator de Necrose Tumoral/genética , Fator de Necrose Tumoral alfa/genética , Alelos , Doenças Autoimunes/diagnóstico , Doenças Autoimunes/imunologia , Doenças Autoimunes/patologia , Cromatina/química , Cromatina/imunologia , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Genoma Humano , Estudo de Associação Genômica Ampla , Doenças Hereditárias Autoinflamatórias/diagnóstico , Doenças Hereditárias Autoinflamatórias/imunologia , Doenças Hereditárias Autoinflamatórias/patologia , Humanos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/patologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/imunologia , Receptores do Fator de Necrose Tumoral/imunologia , Risco , Transdução de Sinais , Fator de Necrose Tumoral alfa/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA