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1.
J Autoimmun ; 101: 145-152, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31054942

RESUMO

BACKGROUND: Cytotoxic T lymphocyte antigen-4 (CTLA-4) limits T-cell activation and is expressed on T-regulatory cells. Human CTLA-4 deficiency results in severe immune dysregulation. Abatacept (CTLA-4 Ig) is approved for the treatment of rheumatoid arthritis (RA) and its mechanism of action is attributed to effects on T-cells. It is known that CTLA-4 modulates the expression of its ligands CD80 and CD86 on antigen presenting cells (APC) by transendocytosis. As B-cells express CD80/CD86 and function as APC, we hypothesize that B-cells are a direct target of abatacept. OBJECTIVES: To investigate direct effects of abatacept on human B-lymphocytes in vitro and in RA patients. METHODS: The effect of abatacept on healthy donor B-cells' phenotype, activation and CD80/CD86 expression was studied in vitro. Nine abatacept-treated RA patients were studied. Seven of these were followed up to 24 months, and two up to 12 months only and treatment response, immunoglobulins, ACPA, RF concentrations, B-cell phenotype and ACPA-specific switched memory B-cell frequency were assessed. RESULTS: B-cell development was unaffected by abatacept. Abatacept treatment resulted in a dose-dependent decrease of CD80/CD86 expression on B-cells in vitro, which was due to dynamin-dependent internalization. RA patients treated with abatacept showed a progressive decrease in plasmablasts and serum IgG. While ACPA-titers only moderately declined, the frequency of ACPA-specific switched memory B-cells significantly decreased. CONCLUSIONS: Abatacept directly targets B-cells by reducing CD80/CD86 expression. Impairment of antigen presentation and T-cell activation may result in altered B-cell selection, providing a new therapeutic mechanism and a base for abatacept use in B-cell mediated autoimmunity.

2.
Front Immunol ; 10: 297, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30941118

RESUMO

Non-canonical NF-κB-pathway signaling is integral in immunoregulation. Heterozygous mutations in NFKB2 have recently been established as a molecular cause of common variable immunodeficiency (CVID) and DAVID-syndrome, a rare condition combining deficiency of anterior pituitary hormone with CVID. Here, we investigate 15 previously unreported patients with primary immunodeficiency (PID) from eleven unrelated families with heterozygous NFKB2-mutations including eight patients with the common p.Arg853* nonsense mutation and five patients harboring unique novel C-terminal truncating mutations. In addition, we describe the clinical phenotype of two patients with proximal truncating mutations. Cohort analysis extended to all 35 previously published NFKB2-cases revealed occurrence of early-onset PID in 46/50 patients (mean age of onset 5.9 years, median 4.0 years). ACTH-deficiency occurred in 44%. Three mutation carriers have deceased, four developed malignancies. Only two mutation carriers were clinically asymptomatic. In contrast to typical CVID, most patients suffered from early-onset and severe disease manifestations, including clinical signs of T cell dysfunction e.g., chronic-viral or opportunistic infections. In addition, 80% of patients suffered from (predominately T cell mediated) autoimmune (AI) phenomena (alopecia > various lymphocytic organ-infiltration > diarrhea > arthritis > AI-cytopenia). Unlike in other forms of CVID, auto-antibodies or lymphoproliferation were not common hallmarks of disease. Immunophenotyping showed largely normal or even increased quantities of naïve and memory CD4+ or CD8+ T-cells and normal T-cell proliferation. NK-cell number and function were also normal. In contrast, impaired B-cell differentiation and hypogammaglobinemia were consistent features of NFKB2-associated disease. In addition, an array of lymphocyte subpopulations, such as regulatory T cell, Th17-, cTFH-, NKT-, and MAIT-cell numbers were decreased. We conclude that heterozygous damaging mutations in NFKB2 represent a distinct PID entity exceeding the usual clinical spectrum of CVID. Impairment of the non-canonical NF-κB pathways affects function and differentiation of numerous lymphocyte-subpopulations and thus causes a heterogeneous, more severe form of PID phenotype with early-onset. Further characteristic features are multifaceted, primarily T cell-mediated autoimmunity, such as alopecia, lymphocytic organ infiltration, and in addition frequently ACTH-deficiency.

3.
Artigo em Inglês | MEDLINE | ID: mdl-29729943

RESUMO

BACKGROUND: Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a negative immune regulator. Heterozygous CTLA4 germline mutations can cause a complex immune dysregulation syndrome in human subjects. OBJECTIVE: We sought to characterize the penetrance, clinical features, and best treatment options in 133 CTLA4 mutation carriers. METHODS: Genetics, clinical features, laboratory values, and outcomes of treatment options were assessed in a worldwide cohort of CTLA4 mutation carriers. RESULTS: We identified 133 subjects from 54 unrelated families carrying 45 different heterozygous CTLA4 mutations, including 28 previously undescribed mutations. Ninety mutation carriers were considered affected, suggesting a clinical penetrance of at least 67%; median age of onset was 11 years, and the mortality rate within affected mutation carriers was 16% (n = 15). Main clinical manifestations included hypogammaglobulinemia (84%), lymphoproliferation (73%), autoimmune cytopenia (62%), and respiratory (68%), gastrointestinal (59%), or neurological features (29%). Eight affected mutation carriers had lymphoma, and 3 had gastric cancer. An EBV association was found in 6 patients with malignancies. CTLA4 mutations were associated with lymphopenia and decreased T-, B-, and natural killer (NK) cell counts. Successful targeted therapies included application of CTLA-4 fusion proteins, mechanistic target of rapamycin inhibitors, and hematopoietic stem cell transplantation. EBV reactivation occurred in 2 affected mutation carriers after immunosuppression. CONCLUSIONS: Affected mutation carriers with CTLA-4 insufficiency can present in any medical specialty. Family members should be counseled because disease manifestation can occur as late as 50 years of age. EBV- and cytomegalovirus-associated complications must be closely monitored. Treatment interventions should be coordinated in clinical trials.

4.
J Allergy Clin Immunol ; 141(2): 730-740, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28554560

RESUMO

BACKGROUND: A subgroup of patients with common variable immunodeficiency (CVID) experience immune dysregulation manifesting as autoimmunity, lymphoproliferation, and organ inflammation and thereby increasing morbidity and mortality. Therefore treatment of these complications demands a deeper comprehension of their cause and pathophysiology. OBJECTIVES: On the basis of the identification of an interferon signature in patients with CVID with secondary complications and a skewed follicular helper T-cell differentiation in defined monogenic immunodeficiencies, we sought to determine the profile of CD4 memory T cells in blood and secondary lymphatic tissues of these patients. METHODS: We quantified TH1/TH2/TH17 CD4 memory T cells in blood and lymph nodes of patients with CVID using flow cytometry, analyzed their function, and correlated all findings to the burden of immune dysregulation. RESULTS: Patients with CVID with immune dysregulation had a skewed memory CD4 T-cell differentiation toward a CXCR3+CCR6- TH1 phenotype both in blood and lymph nodes. Consistent with our phenotypic findings, we observed a higher IFN-γ production in peripheral CD4 memory T cells and lymph node-derived follicular helper T cells of patients with CVID compared with those of healthy control subjects. Increased IFN-γ production was accompanied by a poor germinal center output, an accumulation of T-box transcription factor (T-bet)+ B cells in lymph nodes, and an accumulation of T-bet+CD21low B cells in peripheral blood of affected patients. CONCLUSION: Identification of excessive IFN-γ production by blood and lymph node-derived T cells of patients with CVID with immune dysregulation will offer new therapeutic avenues for this subgroup. CD21low B cells might serve as a marker of this IFN-γ-associated dysregulation.

5.
Inflamm Bowel Dis ; 23(12): 2109-2120, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28930861

RESUMO

BACKGROUND: In contrast to adult-onset inflammatory bowel disease (IBD), where many genetic loci have been shown to be involved in complex disease etiology, early-onset IBD (eoIBD) and associated syndromes can sometimes present as monogenic conditions. As a result, the clinical phenotype and ideal disease management in these patients often differ from those in adult-onset IBD. However, due to high costs and the complexity of data analysis, high-throughput screening for genetic causes has not yet become a standard part of the diagnostic work-up of eoIBD patients. METHODS: We selected 28 genes of interest associated with monogenic IBD and performed targeted panel sequencing in 71 patients diagnosed with eoIBD or early-onset chronic diarrhea to detect causative variants. We compared these results to whole-exome sequencing (WES) data available for 25 of these patients. RESULTS: Target coverage was significantly higher in the targeted gene panel approach compared with WES, whereas the cost of the panel was considerably lower (approximately 25% of WES). Disease-causing variants affecting protein function were identified in 5 patients (7%), located in genes of the IL10 signaling pathway (3), WAS (1), and DKC1 (1). The functional effects of 8 candidate variants in 5 additional patients (7%) are under further investigation. WES did not identify additional causative mutations in 25 patients. CONCLUSIONS: Targeted gene panel sequencing is a fast and effective screening method for monogenic causes of eoIBD that should be routinely established in national referral centers.


Assuntos
Diarreia/etiologia , Predisposição Genética para Doença , Doenças Inflamatórias Intestinais/genética , Idade de Início , Criança , Pré-Escolar , Doença Crônica , Feminino , Estudo de Associação Genômica Ampla , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Recém-Nascido , Masculino , Mutação , Sequenciamento Completo do Exoma
6.
J Allergy Clin Immunol Pract ; 5(6): 1556-1563, 2017 Nov - Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28916432

RESUMO

BACKGROUND: Rituximab (RTX) is approved for induction therapy of granulomatosis with polyangiitis and microscopic polyangiitis. In eosinophilic granulomatosis with polyangiitis (EGPA), organ-threatening manifestations are mainly treated with cyclophosphamide (CYC). RTX as treatment in EGPA has been described in small case series; however long-term data and the efficacy of RTX in EGPA refractory to CYC have not been reported yet. OBJECTIVES: To investigate the efficacy and safety of RTX and conventional immunosuppressive therapy with CYC in EGPA as induction therapy and during long-term follow-up. METHODS: Retrospective analysis of 28 patients with EGPA was done. Treatment response and disease activity were determined by Birmingham Vasculitis Activity Score, C-reactive protein, eosinophils, antineutrophil cytoplasmic antibody, and peripheral CD19+ B cells. RESULTS: Fourteen patients with EGPA treated with RTX were compared with 14 age- and sex-matched patients with EGPA treated with CYC for remission induction; 64% of the RTX-treated patients with EGPA had previously failed CYC treatment. Disease duration was longer and the number of previous immunosuppressants higher in RTX-treated patients. Five RTX-treated patients (36%) and 4 CYC-treated patients (29%) achieved complete remission. All other patients were in partial remission. There was no difference between both groups in respect to treatment response and partial and complete remission. In both treatment groups, eosinophils, C-reactive protein, and IgE levels dropped. Relapse-free survival within an observation period of 36 months was comparable between RTX- and CYC-treated patients. RTX was well tolerated, but resulted in a decline in serum immunoglobulin levels. CONCLUSIONS: RTX was effective in inducing remission and during long-term follow-up in patients with EGPA, even when previously refractory to standard immunosuppressive therapy including CYC. RTX-treated patients should be monitored for hypogammaglobulinemia.


Assuntos
Linfócitos B/imunologia , Síndrome de Churg-Strauss/tratamento farmacológico , Ciclofosfamida/uso terapêutico , Eosinófilos/imunologia , Granulomatose com Poliangiite/tratamento farmacológico , Imunossupressores/uso terapêutico , Rituximab/uso terapêutico , Adulto , Anticorpos Anticitoplasma de Neutrófilos/metabolismo , Proteína C-Reativa/metabolismo , Quimioterapia Combinada , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
7.
J Exp Med ; 214(9): 2547-2562, 2017 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-28747427

RESUMO

Multiple cytokines, including interleukin 6 (IL-6), IL-11, IL-27, oncostatin M (OSM), and leukemia inhibitory factor (LIF), signal via the common GP130 cytokine receptor subunit. In this study, we describe a patient with a homozygous mutation of IL6ST (encoding GP130 p.N404Y) who presented with recurrent infections, eczema, bronchiectasis, high IgE, eosinophilia, defective B cell memory, and an impaired acute-phase response, as well as skeletal abnormalities including craniosynostosis. The p.N404Y missense substitution is associated with loss of IL-6, IL-11, IL-27, and OSM signaling but a largely intact LIF response. This study identifies a novel immunodeficiency with phenotypic similarities to STAT3 hyper-IgE syndrome caused by loss of function of GP130.


Assuntos
Craniossinostoses/genética , Receptor gp130 de Citocina/genética , Síndromes de Imunodeficiência/genética , Mutação de Sentido Incorreto/genética , Pré-Escolar , Receptor gp130 de Citocina/fisiologia , Exoma/genética , Feminino , Humanos , Interleucina-11/deficiência , Interleucina-6/deficiência , Interleucinas/deficiência
8.
BMC Immunol ; 18(1): 34, 2017 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-28651547

RESUMO

BACKGROUND: The ability of anti-cytokine antibodies to play a disease-causing role in the pathogenesis of immunodeficiencies is widely accepted. The aim of this study was to investigate whether autoantibodies against BAFF (important B cell survival signal), APRIL (important plasma cell survival signal), or Interleukin-21 (important cytokine for immunoglobulin class switch) present an alternative mechanism for the development of the following primary antibody deficiencies (PADs): common variable immune deficiency (CVID) or selective IgA deficiency (sIgAD). RESULTS: Two hundred thirty-two sera from patients with PADs were screened for autoantibodies against cytokines by ELISA. Statistical data analysis yielded a significant difference (p < 0.01) between the healthy donor sera and both PAD cohorts. The analysis was deepened by subdividing the patient collective into groups with distinct B cell phenotypes but no significant differences were found. For selected sera with notable high ELISA-read outs functional analysis ensued. Anti-BAFF and anti-APRIL antibodies were further examined by a B cell survival assay, whilst the functional relevance of putative anti-IL-21 autoantibodies was investigated by means of a STAT3 phosphorylation assay. However, the results of these experiments revealed no discernible functional effect. CONCLUSION: Whilst statistical analysis of ELISA results showed significant differences between patients and healthy controls, in our set of patients functional tests yielded no evidence for an involvement of autoantibodies against BAFF, APRIL, or IL-21 in the pathogenesis of CVID or sIgAD.


Assuntos
Autoanticorpos/fisiologia , Fator Ativador de Células B/imunologia , Síndromes de Imunodeficiência/imunologia , Síndromes de Imunodeficiência/fisiopatologia , Interleucinas/imunologia , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/imunologia , Autoanticorpos/sangue , Subpopulações de Linfócitos B/citologia , Subpopulações de Linfócitos B/imunologia , Sobrevivência Celular , Imunodeficiência de Variável Comum/imunologia , Imunodeficiência de Variável Comum/fisiopatologia , Humanos , Deficiência de IgA/imunologia , Deficiência de IgA/fisiopatologia , Interleucinas/metabolismo , Fosforilação , Fator de Transcrição STAT3/imunologia
9.
Arthritis Rheumatol ; 69(8): 1689-1700, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28493328

RESUMO

OBJECTIVE: We aimed to test the relevance of deficiency of adenosine deaminase 2 (DADA2) in patients with antibody deficiency and describe the clinical picture of the disease in adulthood. METHODS: We screened for DADA2 in a cohort of 181 patients with antibody deficiency with or without vascular lesions using next-generation sequencing and targeted Sanger sequencing. All mutations were confirmed by determining the ADA2 enzymatic activity levels in dried plasma spots. Clinical data and laboratory values were collected in a standardized format. RESULTS: Following the diagnosis of 2 siblings in the index family, we identified 9 additional affected patients with compound heterozygous or homozygous CECR1 mutations, containing 6 novel and 4 previously published mutations. The patients' age at evaluation ranged from 13 to 51 years, with a median age of 22 years. Clinically, we saw a broad phenotype, ranging from isolated antibody deficiency to recurrent strokes. All but 1 patient had low numbers of memory B cells. Moreover, B cell function seemed to correlate with inflammation. CONCLUSION: Taken together, our findings indicate that DADA2 presents not only with vasculopathy but also with an immunodeficiency of the B cell compartment. Therefore, patients with antibody deficiency should be screened for DADA2. Anti-tumor necrosis factor treatment might improve immunologic features over time and might be considered in patients without vascular manifestations but with elevated inflammation markers. Conservative management has so far proven to be the choice for our less severely affected adolescent and adult DADA2 patients; however, in patients with severe cytopenias and bone marrow failure, hematopoietic stem cell transplantation should be considered.


Assuntos
Adenosina Desaminase/genética , Síndromes de Imunodeficiência/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Acidente Vascular Cerebral/genética , Adenosina Desaminase/imunologia , Adenosina Desaminase/metabolismo , Adolescente , Adulto , Linfócitos B/imunologia , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Homozigoto , Humanos , Síndromes de Imunodeficiência/imunologia , Peptídeos e Proteínas de Sinalização Intercelular/imunologia , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Mutação , Fenótipo , Análise de Sequência de DNA , Doenças Vasculares/genética , Adulto Jovem
11.
Clin Immunol ; 175: 99-108, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27923702

RESUMO

NFKB1, a component of the canonical NF-κB pathway, was recently reported to be mutated in a limited number of CVID patients. CVID-associated mutations in NFKB2 (non-canonical pathway) have previously been shown to impair NK cell cytotoxic activity. Although a biological function of NFKB1 in non-human NK cells has been reported, the role of NFKB1 mutations for human NK cell biology and disease has not been investigated yet. We decided therefore to evaluate the role of monoallelic NFKB1 mutations in human NK cell maturation and functions. We show that NFKB1 mutated NK cells present impaired maturation, defective cytotoxicity and reduced IFN-γ production upon in vitro stimulation. Furthermore, human IL-2 activated NFKB1 mutated NK cells fail to up-regulate the expression of the activating marker NKp44 and show reduced proliferative capacity. These data suggest that NFKB1 plays an essential novel role for human NK cell maturation and effector functions.


Assuntos
Células Matadoras Naturais/imunologia , Subunidade p50 de NF-kappa B/imunologia , Linhagem Celular Tumoral , Citotoxicidade Imunológica/imunologia , Feminino , Humanos , Interferon gama/imunologia , Interleucina-2/imunologia , Células K562 , Masculino , NF-kappa B/imunologia
12.
J Clin Immunol ; 36(1): 73-84, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26604104

RESUMO

PURPOSE: Gain-of-function (GOF) mutations in the signal transducer and activator of transcription 1 (STAT1) result in unbalanced STAT signaling and cause immune dysregulation and immunodeficiency. The latter is often characterized by the susceptibility to recurrent Candida infections, resulting in the clinical picture of chronic mucocutaneous candidiasis (CMC). This study aims to assess the frequency of GOF STAT1 mutations in a large international cohort of CMC patients. METHODS: STAT1 was sequenced in genomic DNA from 57 CMC patients and 35 healthy family members. The functional relevance of nine different STAT1 variants was shown by flow cytometric analysis of STAT1 phosphorylation in patients' peripheral blood cells (PBMC) after stimulation with interferon (IFN)-α, IFN-γ or interleukin-27 respectively. Extended clinical data sets were collected and summarized for 26 patients. RESULTS: Heterozygous mutations within STAT1 were identified in 35 of 57 CMC patients (61%). Out of 39 familial cases from 11 families, 26 patients (67%) from 9 families and out of 18 sporadic cases, 9 patients (50%) were shown to have heterozygous mutations within STAT1. Thirteen distinct STAT1 mutations are reported in this paper. Eight of these mutations are known to cause CMC (p.M202V, p.A267V, p.R274W, p.R274Q, p.T385M, p.K388E, p.N397D, and p.F404Y). However, five STAT1 variants (p.F172L, p.Y287D, p.P293S, p.T385K and p.S466R) have not been reported before in CMC patients. CONCLUSION: STAT1 mutations are frequently observed in patients suffering from CMC. Thus, sequence analysis of STAT1 in CMC patients is advised. Measurement of IFN- or IL-induced STAT1 phosphorylation in PBMC provides a fast and reliable diagnostic tool and should be carried out in addition to genetic testing.


Assuntos
Candidíase Mucocutânea Crônica/diagnóstico , Síndromes de Imunodeficiência/diagnóstico , Leucócitos Mononucleares/imunologia , Mutação/genética , Fator de Transcrição STAT1/metabolismo , Adulto , Candidíase Mucocutânea Crônica/genética , Células Cultivadas , Citocinas/metabolismo , Análise Mutacional de DNA , Feminino , Humanos , Síndromes de Imunodeficiência/genética , Masculino , Linhagem , Fenótipo , Estrutura Terciária de Proteína/genética , Fator de Transcrição STAT1/genética
13.
Pediatr Infect Dis J ; 35(4): 428-31, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26658378

RESUMO

Caspase-associated recruitment domain-9 (CARD9) deficiency is an autosomal-recessive primary immunodeficiency with genetic defects in Th17 immunity marked by susceptibility to recurrent and invasive Candida infections. We present a case of relapsing Candida albicans meningoencephalitis over 1-year period despite appropriate antifungal therapy. We detected a homozygous p.Q295X mutation in CARD9 as well as a defective interleukin-17 and interferon gamma synthesis in Enzyme-Linked ImmunoSpot tests. We achieved complete clinical remission, and improvement of interleukin-17 secretion with subcutaneous granulocyte colony-stimulating factor) treatment.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/deficiência , Candida albicans , Candidíase Invasiva/tratamento farmacológico , Candidíase Invasiva/etiologia , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Meningoencefalite/tratamento farmacológico , Meningoencefalite/etiologia , Adulto , Anticorpos Antifúngicos/sangue , Anticorpos Antifúngicos/imunologia , Antifúngicos/uso terapêutico , Homozigoto , Humanos , Interleucina-17/sangue , Subpopulações de Linfócitos/imunologia , Subpopulações de Linfócitos/metabolismo , Masculino , Mutação , Recidiva , Resultado do Tratamento
14.
Am J Hum Genet ; 97(3): 389-403, 2015 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-26279205

RESUMO

Common variable immunodeficiency (CVID), characterized by recurrent infections, is the most prevalent symptomatic antibody deficiency. In ∼90% of CVID-affected individuals, no genetic cause of the disease has been identified. In a Dutch-Australian CVID-affected family, we identified a NFKB1 heterozygous splice-donor-site mutation (c.730+4A>G), causing in-frame skipping of exon 8. NFKB1 encodes the transcription-factor precursor p105, which is processed to p50 (canonical NF-κB pathway). The altered protein bearing an internal deletion (p.Asp191_Lys244delinsGlu; p105ΔEx8) is degraded, but is not processed to p50ΔEx8. Altered NF-κB1 proteins were also undetectable in a German CVID-affected family with a heterozygous in-frame exon 9 skipping mutation (c.835+2T>G) and in a CVID-affected family from New Zealand with a heterozygous frameshift mutation (c.465dupA) in exon 7. Given that residual p105 and p50­translated from the non-mutated alleles­were normal, and altered p50 proteins were absent, we conclude that the CVID phenotype in these families is caused by NF-κB1 p50 haploinsufficiency.


Assuntos
Imunodeficiência de Variável Comum/genética , Haploinsuficiência/genética , Subunidade p50 de NF-kappa B/genética , Austrália , Sequência de Bases , Western Blotting , Primers do DNA/genética , Exoma/genética , Humanos , Microscopia de Fluorescência , Dados de Sequência Molecular , Países Baixos , Nova Zelândia , Análise de Sequência de DNA
15.
Nat Med ; 20(12): 1410-1416, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25329329

RESUMO

The protein cytotoxic T lymphocyte antigen-4 (CTLA-4) is an essential negative regulator of immune responses, and its loss causes fatal autoimmunity in mice. We studied a large family in which five individuals presented with a complex, autosomal dominant immune dysregulation syndrome characterized by hypogammaglobulinemia, recurrent infections and multiple autoimmune clinical features. We identified a heterozygous nonsense mutation in exon 1 of CTLA4. Screening of 71 unrelated patients with comparable clinical phenotypes identified five additional families (nine individuals) with previously undescribed splice site and missense mutations in CTLA4. Clinical penetrance was incomplete (eight adults of a total of 19 genetically proven CTLA4 mutation carriers were considered unaffected). However, CTLA-4 protein expression was decreased in regulatory T cells (Treg cells) in both patients and carriers with CTLA4 mutations. Whereas Treg cells were generally present at elevated numbers in these individuals, their suppressive function, CTLA-4 ligand binding and transendocytosis of CD80 were impaired. Mutations in CTLA4 were also associated with decreased circulating B cell numbers. Taken together, mutations in CTLA4 resulting in CTLA-4 haploinsufficiency or impaired ligand binding result in disrupted T and B cell homeostasis and a complex immune dysregulation syndrome.


Assuntos
Agamaglobulinemia/genética , Doenças Autoimunes/genética , Antígeno CTLA-4/genética , Linfócitos T Reguladores/imunologia , Adolescente , Adulto , Agamaglobulinemia/imunologia , Anemia Hemolítica Autoimune/genética , Anemia Hemolítica Autoimune/imunologia , Animais , Doenças Autoimunes/imunologia , Linfócitos B/imunologia , Antígeno B7-1/metabolismo , Antígeno CTLA-4/imunologia , Criança , Códon sem Sentido , Endocitose/genética , Endocitose/imunologia , Éxons , Feminino , Granuloma/genética , Granuloma/imunologia , Heterozigoto , Humanos , Doenças do Sistema Imunitário/genética , Doenças Pulmonares Intersticiais/genética , Doenças Pulmonares Intersticiais/imunologia , Masculino , Camundongos , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Linhagem , Poliendocrinopatias Autoimunes/genética , Poliendocrinopatias Autoimunes/imunologia , Púrpura Trombocitopênica Idiopática/genética , Púrpura Trombocitopênica Idiopática/imunologia , Recidiva , Infecções Respiratórias/genética , Infecções Respiratórias/imunologia , Síndrome , Adulto Jovem
16.
BMC Immunol ; 15: 10, 2014 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-24581234

RESUMO

BACKGROUND: Inflammatory bowel disease constitutes a heterogeneous group of conditions, whose aetiology is only partly understood. The prevailing hypothesis on its pathogenesis is that IBD is the result of an inadequate immune response to the resident bacterial flora of the intestine. An autoimmune background, however, has been discussed since the 1950s. Lately, it has been shown that failures in interleukin-10 (IL-10) signalling due to IL-10- and IL-10 receptor (IL-10R) mutations result in IBD. Our study aimed at investigating the existence of inhibitory autoantibodies against IL-10 and IL-10R in IBD patients capable of down-modulating IL-10 signalling thereby mimicking IL-10 or IL-10R deficiency. RESULTS: Thirteen IBD patients had IgG autoantibodies against IL-10, IL-10RA and/or IL-10RB, and three patients had IgA autoantibodies against IL-10. However, the absolute OD values of the serum antibodies measured by ELISA were low, there was overall no significant difference between patients and controls, and positive sera had no neutralizing activity. CONCLUSION: No evidence for an involvement of autoantibodies against IL-10 or IL-10R in the pathogenesis of inflammatory bowel disease could be established.


Assuntos
Autoanticorpos/imunologia , Doenças Inflamatórias Intestinais/imunologia , Doenças Inflamatórias Intestinais/metabolismo , Interleucina-10/imunologia , Interleucina-10/metabolismo , Receptores de Interleucina-10/imunologia , Transdução de Sinais , Anticorpos Neutralizantes/imunologia , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina A/imunologia , Imunoglobulina G/imunologia , Receptores de Interleucina-10/metabolismo
17.
J Allergy Clin Immunol ; 131(3): 825-30, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23158016

RESUMO

BACKGROUND: Inherited deficiencies of IL-10 or IL-10 receptor (IL-10R) lead to immune dysregulation with life-threatening early-onset enterocolitis. OBJECTIVES: We sought to gather clinical data of IL-10/IL-10R-deficient patients and devise guidelines for diagnosis and management, including hematopoietic stem cell transplantation (HSCT). METHODS: We enrolled 40 patients with early-onset enterocolitis and screened for mutations in IL10/IL10R using genetic studies, functional studies, or both of the IL-10 signaling pathway. Medical records of IL-10/IL-10R-deficient patients were reviewed and compiled. RESULTS: Of 40 patients, we identified 7 with novel mutations, predominantly in consanguineous families with more than 1 affected member. IL-10/IL-10R-deficient patients had intractable enterocolitis, perianal disease, and fistula formation. HSCT was carried out in 2 patients with IL-10 deficiency and 1 patient with IL-10R α chain deficiency and proved to be an effective therapy, leading to rapid improvement of clinical symptoms and quality of life. CONCLUSION: Because the defect in patients with IL-10/IL-10R deficiency resides in hematopoietic lineage cells and their colitis is resistant to standard immunosuppressive therapy, HSCT should be considered early as a potentially curative therapeutic option.


Assuntos
Colite/terapia , Transplante de Células-Tronco Hematopoéticas , Síndromes de Imunodeficiência/terapia , Interleucina-10/deficiência , Receptores de Interleucina-10/deficiência , Adulto , Criança , Pré-Escolar , Colite/diagnóstico , Colite/etiologia , Colite/genética , Feminino , Humanos , Síndromes de Imunodeficiência/complicações , Síndromes de Imunodeficiência/diagnóstico , Síndromes de Imunodeficiência/genética , Lactente , Recém-Nascido , Masculino , Mutação
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