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2.
Blood ; 134(1): 9-21, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-30940614

RESUMO

Evans syndrome (ES) is a rare severe autoimmune disorder characterized by the combination of autoimmune hemolytic anemia and immune thrombocytopenia. In most cases, the underlying cause is unknown. We sought to identify genetic defects in pediatric ES (pES), based on a hypothesis of strong genetic determinism. In a national, prospective cohort of 203 patients with early-onset ES (median [range] age at last follow-up: 16.3 years ([1.2-41.0 years]) initiated in 2004, 80 nonselected consecutive individuals underwent genetic testing. The clinical data were analyzed as a function of the genetic findings. Fifty-two patients (65%) received a genetic diagnosis (the M+ group): 49 carried germline mutations and 3 carried somatic variants. Thirty-two (40%) had pathogenic mutations in 1 of 9 genes known to be involved in primary immunodeficiencies (TNFRSF6, CTLA4, STAT3, PIK3CD, CBL, ADAR1, LRBA, RAG1, and KRAS), whereas 20 patients (25%) carried probable pathogenic variants in 16 genes that had not previously been reported in the context of autoimmune disease. Lastly, no genetic abnormalities were found in the remaining 28 patients (35%, the M- group). The M+ group displayed more severe disease than the M- group, with a greater frequency of additional immunopathologic manifestations and a greater median number of lines of treatment. Six patients (all from the M+ group) died during the study. In conclusion, pES was potentially genetically determined in at least 65% of cases. Systematic, wide-ranging genetic screening should be offered in pES; the genetic findings have prognostic significance and may guide the choice of a targeted treatment.

3.
PLoS One ; 13(10): e0205826, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30365510

RESUMO

Mutations in interleukin-10 receptor (IL-10R) genes are one cause of very early-onset inflammatory bowel disease with perianal lesions, which can be cured by hematopoietic stem cell transplantation. Using a functional test, which assesses responsiveness of peripheral monocytes to IL-10, we identified three unrelated Portuguese patients carrying two novel IL-10RB mutations. In the three patients, sequencing of genomic DNA identified the same large deletion of exon 3 which precluded protein expression. This mutation was homozygous in two patients born from consanguineous families and heterozygous in the third patient born from unrelated parents. Microsatellite analysis of the IL10RB genomic region revealed a common haplotype in the three Portuguese families pointing to a founder deletion inherited from a common ancestor 400 years ago. In the third patient, surface expression of IL-10R was normal but signaling in response to IL-10 was impaired. Complementary DNA sequencing and next-generation sequencing of IL10RB locus with custom-made probes revealed a ≈ 6 Kb duplication encompassing the exon 6 which leads to a frameshift mutation and a loss of the TYK2-interacting Box 2 motif. Altogether, we describe two novel copy number variations in IL10RB, one with founder effect and one preserving cell surface expression but abolishing signaling.

4.
J Crohns Colitis ; 2018 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-29788237

RESUMO

Background and Aims: An expanding number of monogenic defects have been identified as causative of severe forms of very early-onset inflammatory bowel diseases (VEO-IBD). The present study aimed at defining how next-generation sequencing (NGS) methods can be used to improve identification of known molecular diagnosis and adapt treatment. Methods: 207 children were recruited in 45 Paediatric centres through an international collaborative network (ESPGHAN GENIUS working group) with a clinical presentation of severe VEO-IBD (n=185) or an anamnesis suggestive of a monogenic disorder (n=22). Patients were divided at inclusion into three phenotypic subsets: predominantly small bowel inflammation, colitis with perianal lesions, and colitis only. Methods to obtain molecular diagnosis included functional tests followed by specific Sanger sequencing, custom-made targeted NGS, and in selected cases whole exome sequencing (WES) of parents-child trios. Genetic findings were validated clinically and/or functionally. Results: Molecular diagnosis was achieved in 66/207 children (32%): 61% with small bowel inflammation, 39% with colitis and perianal lesions and 18% with colitis only. Targeted NGS pinpointed gene mutations causative of atypical presentations and identified large exonic copy number variations previously missed by WES. Conclusions: Our results lead us to propose an optimised diagnostic strategy to identify known monogenic causes of severe IBD.

5.
Front Immunol ; 9: 718, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29686686

RESUMO

Objective: Autoimmune lymphoproliferative syndrome (ALPS) with FAS mutation (ALPS-FAS) is a nonmalignant, noninfectious, lymphoproliferative disease with autoimmunity. Given the central role of natural regulatory T cells (nTregs) in the control of lymphoproliferation and autoimmunity, we assessed nTreg-suppressive function in 16 patients with ALPS-FAS. Results: The proportion of CD25highCD127low Tregs was lower in ALPS-FAS patients than in healthy controls. This subset was correlated with a reduced CD25 expression in CD3+CD4+ T cells from ALPS patients and thus an abnormally low proportion of CD25highFOXP3+ Helios+ T cells. The ALPS patients also displayed a high proportion of naïve Treg (FOXP3lowCD45RA+) and an unusual subpopulation (CD4+CD127lowCD15s+CD45RA+). Despite this abnormal phenotype, the CD25highCD127low Tregs' suppressive function was unaffected. Furthermore, conventional T cells from FAS-mutated patients showed normal levels of sensitivity to Treg suppression. Conclusion: An abnormal Treg phenotype is observed in circulating lymphocytes of ALPS patients. However, these Tregs displayed a normal suppressive function on T effector proliferation in vitro. This is suggesting that lymphoproliferation observed in ALPS patients does not result from Tregs functional defect or T effector cells insensitivity to Tregs suppression.

6.
Clin Immunol ; 188: 52-57, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29330115

RESUMO

Evans syndrome (ES) is defined by the combination of autoimmune hemolytic anemia and immune thrombocytopenia. Clinical presentation includes manifestations of immune dysregulation, found in primary immune deficiencies, autoimmune lymphoproliferative syndrome with FAS (ALPS-FAS), Cytotoxic T Lymphocyte Antigen-4 (CTLA-4) and Lipopolysaccharide-Responsive vesicle trafficking Beige-like and Anchor protein (LRBA) defects. We report the clinical history and genetic results of 18 children with ES after excluding ALPS-FAS. Thirteen had organomegaly, five lymphocytic infiltration of non-lymphoid organs, nine hypogammaglobulinemia and fifteen anomalies in lymphocyte phenotyping. Seven patients had genetic defects: three CTLA4 mutations (c.151C>T; c.109+1092_568-512del; c.110-2A>G) identified by Sanger sequencing and four revealed by Next Generation Sequencing: LRBA (c.2450+1C>T), STAT3 gain-of-function (c.2147C>T; c.2144C>T) and KRAS (c.37G>T). No feature emerged to distinguish patients with or without genetic diagnosis. Our data on pediatric-onset ES should prompt physicians to perform extensive screening for mutations in the growing pool of genes involved in primary immune deficiencies with autoimmunity.

7.
J Exp Med ; 214(6): 1769-1785, 2017 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-28484079

RESUMO

Activation of the cyclic dinucleotide sensor stimulator of interferon (IFN) genes (STING) is critical for IFN and inflammatory gene expression during innate immune responses. However, the role of STING in adaptive immunity is still unknown. In this study, we show that STING activation reduces the proliferation of T lymphocytes. This activity was independent of TBK1 and IRF3 recruitment and of type I IFN but required a distinct C-terminal domain of STING that activates NF-κB. Inhibition of cell proliferation by STING required its relocalization to the Golgi apparatus and caused mitotic errors. T lymphocytes from patients carrying constitutive active mutations in TMEM173 encoding STING showed impaired proliferation and reduced numbers of memory cells. Endogenous STING inhibited proliferation of mouse T lymphocytes. Therefore, STING, a critical innate sensor, also functions intrinsically in cells of the adaptive immune system to inhibit proliferation.


Assuntos
Imunidade Inata , Proteínas de Membrana/metabolismo , Linfócitos T/citologia , Linfócitos T/metabolismo , Sítios de Ligação , Proliferação de Células , Células Dendríticas/metabolismo , Humanos , Fator Regulador 3 de Interferon/metabolismo , Proteínas de Membrana/química , Mitose , Proteínas Mutantes/metabolismo , Domínios Proteicos , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais
8.
J Pediatr Gastroenterol Nutr ; 64(3): 378-384, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27253662

RESUMO

OBJECTIVE: Early-onset inflammatory bowel diseases can result from a wide spectrum of rare mendelian disorders. Early molecular diagnosis is crucial in defining treatment and in improving life expectancy. Herein we aimed at defining the mechanism of an immunodeficiency-polyendrocrinopathy and enteropathy-X-linked (IPEX)-like disease combined with a severe immunodeficiency in 2 siblings born from distantly related parents. METHODS: Whole exome sequencing was performed on blood-extracted genomic DNA from the 2 affected children and their parents on the genomic platform of Institut IMAGINE. Candidate gene mutation was identified using the in-house software PolyWeb and confirmed by Sanger sequencing. Protein expression was determined by western blot. Flow cytometry was used to assess consequences of the mutation on lymphocyte phenotype and nuclear factor-kappa B (NF-κB) activation at diagnosis and after treatment by hematopoietic stem cell transplantation. RESULTS: We identified a homozygous missense mutation in mucosa-associated lymphoid tissue lymphoma translocation 1 gene (MALT1), which precluded protein expression. In keeping with the known function of MALT1, NF-κB-dependent lymphocyte activation was severely impaired. Moreover, there was a drastic reduction in Forkhead box P3 (FOXP3) regulatory T cells accounting for the IPEX-like phenotype. Following identification of the mutation, both children received hematopoietic stem cell transplantation, which permitted full clinical recovery. Immunological workup at 6 and 12 months after transplantation showed normal NF-κB activation and correction of regulatory T cells frequency. CONCLUSIONS: Along with FOXP3, interleukin 2 receptor alpha chain (IL2RA), and cytotoxic T-lymphocyte protein 4 precursor (CTLA-4) mutations, MALT1 deficiency should now be considered as a possible cause of IPEX-like syndrome associated with immunodeficiency that can be cured by hematopoietic stem cell transplantation.


Assuntos
Diabetes Mellitus Tipo 1/congênito , Diarreia/genética , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças do Sistema Imunitário/congênito , Proteína de Translocação 1 do Linfoma de Tecido Linfoide Associado à Mucosa/deficiência , Mutação de Sentido Incorreto , Criança , Pré-Escolar , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/genética , Diarreia/diagnóstico , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Marcadores Genéticos , Homozigoto , Humanos , Doenças do Sistema Imunitário/diagnóstico , Doenças do Sistema Imunitário/genética , Masculino , Proteína de Translocação 1 do Linfoma de Tecido Linfoide Associado à Mucosa/genética , Irmãos
9.
Clin Immunol ; 168: 88-93, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27057999

RESUMO

LRBA (lipopolysaccharide-responsive and beige-like anchor protein) deficiency associates immune deficiency, lymphoproliferation, and various organ-specific autoimmunity. To date, prevalent symptoms are autoimmune cytopenias and enteropathy, and lymphocytic interstitial lung disease. In 2 siblings from a consanguineous family presenting with early onset polyautoimmunity, we presumed autosomal recessive inheritance and performed whole exome sequencing. We herein report the first case of early-onset, severe, chronic polyarthritis associated with LRBA deficiency. A novel 1bp insertion in the LRBA gene, abolishing protein expression, was identified in this family. Among the 2 brothers homozygous for LRBA mutation, one developed Evans syndrome and deceased at age 8.5 from complications of severe autoimmune thrombocytopenia. His brother, who carried the same homozygous LRBA mutation, early-onset erosive polyarthritis associated with chronic, bilateral, anterior uveitis and early onset type 1 diabetes mellitus. This report widens the clinical spectrum of LRBA deficiency and, in lights of the variable phenotypes described so far, prompts us to screen for this disease in patients with multiple autoimmune symptoms in the family, including severe, erosive, polyarticular juvenile arthritis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Artrite/genética , Autoimunidade/genética , Mutação , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adolescente , Artrite/complicações , Artrite/metabolismo , Pré-Escolar , Doença Crônica , Consanguinidade , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Exoma/genética , Saúde da Família , Evolução Fatal , Feminino , Humanos , Immunoblotting , Masculino , Linhagem , Análise de Sequência de DNA , Irmãos , Uveíte Anterior/complicações , Uveíte Anterior/genética , Uveíte Anterior/metabolismo
10.
J Clin Invest ; 124(12): 5516-20, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25401470

RESUMO

Innate immunity to viral infection involves induction of the type I IFN response; however, dysfunctional regulation of this pathway leads to inappropriate inflammation. Here, we evaluated a nonconsanguineous family of mixed European descent, with 4 members affected by systemic inflammatory and autoimmune conditions, including lupus, with variable clinical expression. We identified a germline dominant gain-of-function mutation in TMEM173, which encodes stimulator of type I IFN gene (STING), in the affected individuals. STING is a key signaling molecule in cytosolic DNA-sensing pathways, and STING activation normally requires dimerization, which is induced by 2'3' cyclic GMP-AMP (cGAMP) produced by the cGAMP synthase in response to cytosolic DNA. Structural modeling supported constitutive activation of the mutant STING protein based on stabilized dimerization. In agreement with the model predictions, we found that the STING mutant spontaneously localizes in the Golgi of patient fibroblasts and is constitutively active in the absence of exogenous 2'3'-cGAMP in vitro. Accordingly, we observed elevated serum IFN activity and a type I IFN signature in peripheral blood from affected family members. These findings highlight the key role of STING in activating both the innate and adaptive immune responses and implicate aberrant STING activation in features of human lupus.


Assuntos
Doenças Genéticas Inatas/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Mutação , Multimerização Proteica/imunologia , Transdução de Sinais/imunologia , Imunidade Adaptativa/genética , Adulto , Idoso , Pré-Escolar , Feminino , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/patologia , Humanos , Imunidade Inata/genética , Interferon Tipo I/genética , Interferon Tipo I/imunologia , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/patologia , Masculino , Proteínas de Membrana , Nucleotídeos Cíclicos/genética , Nucleotídeos Cíclicos/imunologia , Multimerização Proteica/genética , Transdução de Sinais/genética , Síndrome
11.
Blood ; 124(10): 1597-609, 2014 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-24970930

RESUMO

Autoimmune lymphoproliferative syndrome (ALPS) caused by impaired FAS-mediated apoptosis of lymphocytes is characterized by lymphoproliferation, autoimmunity, but also an increased risk of invasive bacterial infection, notably following splenectomy. We surveyed a cohort of 100 ALPS patients (including 33 splenectomized) and found that 12 (10 splenectomized) had experienced 23 invasive bacterial infections mainly caused by Streptococcus pneumoniae. This vulnerability was associated with evidence of defective B-cell function characterized by low serum immunoglobulin (Ig) M, low IgM antibody production in response to S pneumoniae following nonconjugated immunization, and low blood memory B-cells counts (including marginal zone [MZ] B-cell counts). This immunodeficiency strongly correlated with intensity of lymphoproliferation. Spleen sections from 9 ALPS patients revealed double-negative T-cell (DN-T) infiltration of the MZ, which was depleted of B cells. MZ in ALPS patients contained an abnormally thick layer of MAdCAM-1((+)) stromal cells and an excess of DN-Ts. DN-Ts were shown to express MAdCAM-1 ligand, the α4ß7 integrin. These observations suggest that accumulating DN-Ts are trapped within stromal cell meshwork and interfere with correct localization of MZ B cells. Similar observations were made in spleens of fas-deficient mice. Our data revealed an unexpected mechanism by which ALPS results in anti-polysaccharide IgM antibody production-specific defect. Splenectomy should be avoided.


Assuntos
Formação de Anticorpos , Síndrome Linfoproliferativa Autoimune/imunologia , Síndrome Linfoproliferativa Autoimune/patologia , Lipopolissacarídeos/imunologia , Baço/imunologia , Baço/patologia , Adolescente , Adulto , Animais , Síndrome Linfoproliferativa Autoimune/epidemiologia , Síndrome Linfoproliferativa Autoimune/cirurgia , Criança , Pré-Escolar , Humanos , Lactente , Recém-Nascido , Camundongos , Camundongos Transgênicos , Baço/cirurgia , Esplenectomia/efeitos adversos , Esplenectomia/estatística & dados numéricos , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/imunologia , Streptococcus pneumoniae/crescimento & desenvolvimento , Streptococcus pneumoniae/imunologia , Adulto Jovem
13.
J Allergy Clin Immunol ; 131(2): 486-90, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22857792

RESUMO

BACKGROUND: Autoimmune lymphoproliferative syndrome (ALPS) is characterized by chronic nonmalignant lymphoproliferation, accumulation of double-negative T cells, hypergammaglobulinemia G and A, and autoimmune cytopenia. OBJECTIVES: Although mostly associated with FAS mutations, different genetic defects leading to impaired apoptosis have been described in patients with ALPS, including the FAS ligand gene (FASLG) in rare cases. Here we report on the first case of complete FAS ligand deficiency caused by a homozygous null mutant. METHODS: Double-negative T-cell counts and plasma IL-10 and FAS ligand concentrations were determined as ALPS markers. The FASLG gene was sequenced, and its expression was analyzed by means of Western blotting. FAS ligand function was assessed based on reactivation-induced cell death. RESULTS: We describe a patient born to consanguineous parents who presented with a severe form of ALPS caused by FASLG deficiency. Although the clinical presentation was compatible with a homozygous FAS mutation, FAS-induced apoptosis was normal, and plasma FAS ligand levels were not detectable. This patient carries a homozygous, germline, single-base-pair deletion in FASLG exon 1, leading to a premature stop codon (F87fs x95) and a complete defect in FASLG expression. The healthy parents were each heterozygous for the mutation, confirming its recessive trait. CONCLUSION: FAS ligand deficiency should be screened in patients presenting with ALPS features but lacking the usual markers, including plasma soluble FAS ligand and an in vitro apoptotic defect. An activation-induced cell death test could help in discrimination.


Assuntos
Síndrome Linfoproliferativa Autoimune/genética , Proteína Ligante Fas/deficiência , Proteína Ligante Fas/genética , Mutação , Síndrome Linfoproliferativa Autoimune/imunologia , Proteína Ligante Fas/imunologia , Homozigoto , Humanos , Lactente , Masculino
14.
Blood ; 118(18): 4798-807, 2011 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-21885602

RESUMO

Autoimmune lymphoproliferative syndrome (ALPS) is a genetic disorder characterized by early-onset, chronic, nonmalignant lymphoproliferation, autoimmune manifestations, and susceptibility to lymphoma. The majority of ALPS patients carry heterozygous germline (ALPS-FAS) or somatic mutations (ALPS-sFAS) of the TNFRSF6 gene coding for FAS. Although the clinical features of ALPS have been described previously, long-term follow-up data on morbidity and mortality are scarce. We performed a retrospective analysis of clinical and genetic features of 90 ALPS-FAS and ALPS-sFAS patients monitored over a median period of 20.5 years. Heterozygous germline mutations of TNFRSF6 were identified in 83% of probands. Somatic TNFRSF6 mutations were found in 17% of index cases (all located within the intracellular domain of FAS). Sixty percent of the ALPS-FAS patients with mutations in the extracellular domain had a somatic mutation affecting the second allele of TNFRSF6; age at onset was later in these patients. No other genotype-phenotype correlations could be found. Long-term analysis confirmed a trend toward spontaneous remission of lymphoproliferation in adulthood but mixed outcomes for autoimmune manifestations. We observed significant and potentially life-threatening disease and treatment-related morbidity, including a high risk of sepsis after splenectomy that calls for careful long-term monitoring of ALPS patients. We also noted a significantly greater occurrence of disease-related symptoms in male than in female patients.


Assuntos
Síndrome Linfoproliferativa Autoimune/genética , Mutação , Receptor fas/genética , Adolescente , Adulto , Idoso , Síndrome Linfoproliferativa Autoimune/sangue , Síndrome Linfoproliferativa Autoimune/complicações , Síndrome Linfoproliferativa Autoimune/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Coleta de Dados , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Mutação/fisiologia , Adulto Jovem
15.
J Clin Invest ; 121(1): 106-12, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21183795

RESUMO

Autoimmune diseases develop in approximately 5% of humans. They can arise when self-tolerance checkpoints of the immune system are bypassed as a consequence of inherited mutations of key genes involved in lymphocyte activation, survival, or death. For example, autoimmune lymphoproliferative syndrome (ALPS) results from defects in self-tolerance checkpoints as a consequence of mutations in the death receptor-encoding gene TNF receptor superfamily, member 6 (TNFRSF6; also known as FAS). However, some mutation carriers remain asymptomatic throughout life. We have now demonstrated in 7 ALPS patients that the disease develops as a consequence of an inherited TNFRSF6 heterozygous mutation combined with a somatic genetic event in the second TNFRSF6 allele. Analysis of the patients' CD4(-)CD8(-) (double negative) T cells--accumulation of which is a hallmark of ALPS--revealed that in these cells, 3 patients had somatic mutations in their second TNFRSF6 allele, while 4 patients had loss of heterozygosity by telomeric uniparental disomy of chromosome 10. This observation provides the molecular bases of a nonmalignant autoimmune disease development in humans and may shed light on the mechanism underlying the occurrence of other autoimmune diseases.


Assuntos
Síndrome Linfoproliferativa Autoimune/genética , Mutação , Receptor fas/genética , Adolescente , Adulto , Síndrome Linfoproliferativa Autoimune/imunologia , Cromossomos Humanos Par 10/genética , Feminino , Mutação em Linhagem Germinativa , Heterozigoto , Humanos , Perda de Heterozigosidade , Linfócitos Nulos/imunologia , Masculino , Pessoa de Meia-Idade , Modelos Genéticos , Linhagem , Dissomia Uniparental , Adulto Jovem
16.
Gastroenterology ; 139(3): 770-8, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20537998

RESUMO

BACKGROUND & AIMS: Little is known about the pathophysiology of early onset forms of autoimmune enteropathy (AIE). AIE has been associated with mutations in FOXP3-a transcription factor that controls regulatory T-cell development and function. We analyzed the molecular basis of neonatal or early postnatal AIE using clinical, genetic, and functional immunological studies. METHODS: Gastroenterological and immunological features were analyzed in 9 boys and 2 girls with AIE that began within the first 5 months of life. FOXP3 and IL2RA were genotyped in peripheral blood monocytes. FOXP3 messenger RNA and protein expression were analyzed using reverse-transcription polymerase chain reaction, flow cytometry, and confocal immunofluorescence of CD4(+) T cells. Regulatory T-cell function (CD4(+)CD25(+)) was assayed in coculture systems. RESULTS: AIE associated with extraintestinal autoimmunity was severe and life-threatening; all patients required total parenteral nutrition. Regulatory T cells from 7 patients had altered function and FOXP3 mutations that resulted in lost or reduced FOXP3 protein expression; 2 infants had reduced regulatory T-cell activity and reduced levels of FOXP3 protein, although we did not detect mutations in FOXP3 coding region, poly-A site, or promoter region (called FOXP3-dependent AIE). Two patients had a normal number of regulatory T cells that expressed normal levels of FOXP3 protein and normal regulatory activity in in vitro coculture assays (called FOXP3-independent AIE). No mutations in IL2RA were found. CONCLUSIONS: Most cases of AIE are associated with alterations in regulatory T-cell function; some, but not all, cases have mutations that affect FOXP3 expression levels. Further studies are needed to identify mechanisms of AIE pathogenesis.


Assuntos
Doenças Autoimunes/imunologia , Fatores de Transcrição Forkhead/sangue , Enteropatias/imunologia , Linfócitos T Reguladores/imunologia , Idade de Início , Doenças Autoimunes/genética , Doenças Autoimunes/mortalidade , Doenças Autoimunes/terapia , Contagem de Linfócito CD4 , Estudos de Casos e Controles , Células Cultivadas , Criança , Pré-Escolar , Técnicas de Cocultura , Regulação para Baixo , Feminino , Citometria de Fluxo , Fatores de Transcrição Forkhead/genética , Humanos , Imunossupressores/uso terapêutico , Lactente , Recém-Nascido , Subunidade alfa de Receptor de Interleucina-2/sangue , Subunidade alfa de Receptor de Interleucina-2/genética , Enteropatias/genética , Enteropatias/mortalidade , Enteropatias/terapia , Masculino , Microscopia Confocal , Mutação , Fases de Leitura Aberta , Nutrição Parenteral Total , Regiões Promotoras Genéticas , RNA Mensageiro/sangue , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Índice de Gravidade de Doença , Resultado do Tratamento
17.
Eur J Immunol ; 39(7): 1966-76, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19548248

RESUMO

Complete lack of function of the tyrosine kinase ZAP70 in humans results in a severe immunodeficiency, characterized by a lack of mature CD8(+) T cells and non-functional CD4(+) T cells. We report herein an immunodeficiency with an inherited hypomorphic mutation of ZAP70 due to a single G-to-A substitution in a non-coding intron. This mutation introduces a new acceptor splice site and allows low levels of normal alternative splicing and of WT ZAP70 expression. This partial deficiency results in a compromised TCR signaling that was totally restored by increased expression of ZAP70, demonstrating that defective activation of the patient T cells was indeed caused by the low level of ZAP70 expression. This partial ZAP70 deficiency was associated with an attenuated clinical and immunological phenotype as compared with complete ZAP70 deficiency. CD4(+) helper T-cell populations including, follicular helper T cells, Th1, Th17 and Treg were detected in the blood. Finally, the patient had no manifestation of autoimmunity suggesting that the T-cell tolerogenic functions were not compromised, in contrast to what has been observed in mice carrying hypomorphic mutations of Zap70. This report extends the phenotype spectrum of ZAP70 deficiency with a residual function of ZAP70.


Assuntos
Síndromes de Imunodeficiência/genética , Mutação Puntual , Proteína-Tirosina Quinase ZAP-70/genética , Sequência de Aminoácidos , Autoimunidade/imunologia , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Cálcio/metabolismo , Criança , Análise Mutacional de DNA , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Síndromes de Imunodeficiência/imunologia , Síndromes de Imunodeficiência/metabolismo , Contagem de Linfócitos , Masculino , Receptores de Antígenos de Linfócitos T/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais , Transfecção , Proteína-Tirosina Quinase ZAP-70/metabolismo
18.
Blood ; 113(13): 3027-30, 2009 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-19176318

RESUMO

Autoimmune lymphoproliferative syndrome (ALPS) is characterized by splenomegaly, lymphadenopathy, hypergammaglobulinemia, accumulation of double-negative TCRalphabeta(+) CD4(-)CD8(-) T cells (DNT cells), and autoimmunity. Previously, DNT cell detection and a functional defect of T cells in a FAS-induced apoptosis test in vitro had been used for ALPS diagnosis. However, a functional defect can also be detected in mutation-positive relatives (MPRs) who remain free of any ALPS-related disease. In contrast, lymphocytes from patients carrying a somatic mutation of FAS exhibit normal sensitivity to FAS-induced apoptosis in vitro. We assessed the soluble FAS-L concentration in the plasma of ALPS patients carrying FAS mutations. Overall, we showed that determination of the FAS-L represents, together with the IL-10 concentration and the DNT cell percentage, a reliable tool for the diagnosis of ALPS.


Assuntos
Doenças Autoimunes/diagnóstico , Proteína Ligante Fas/metabolismo , Interleucina-10/metabolismo , Transtornos Linfoproliferativos/diagnóstico , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Linfócitos T/metabolismo , Receptor fas/genética , Adolescente , Adulto , Doenças Autoimunes/sangue , Doenças Autoimunes/genética , Doenças Autoimunes/metabolismo , Biomarcadores/sangue , Biomarcadores/metabolismo , Antígenos CD4/sangue , Antígenos CD4/metabolismo , Antígenos CD8/sangue , Antígenos CD8/metabolismo , Estudos de Casos e Controles , Criança , Pré-Escolar , Proteína Ligante Fas/sangue , Humanos , Lactente , Recém-Nascido , Interleucina-10/sangue , Transtornos Linfoproliferativos/sangue , Transtornos Linfoproliferativos/genética , Transtornos Linfoproliferativos/metabolismo , Pessoa de Meia-Idade , Mutação/fisiologia , Síndrome , Linfócitos T/patologia , Adulto Jovem , Receptor fas/fisiologia
19.
Blood ; 110(13): 4285-92, 2007 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-17724145

RESUMO

Activation-induced cell death (AICD) is involved in peripheral tolerance by controlling the expansion of repeatedly stimulated T cells via an apoptotic Fas (CD95; APO-1)-dependent pathway. The TNFRSF-6 gene encoding Fas is mutated in children suffering from autoimmune lymphoproliferative syndrome (ALPS), which is characterized by lymphoproliferation and autoimmunity. We examined AICD in Fas-deficient T cells from ALPS patients. We showed that primary activated Fas-deficient T cells die by apoptosis after repeated T cell antigen receptor (TCR) stimulation despite resistance to Fas-mediated cell death. This Fas-independent AICD was found to be mediated through a cytotoxic granules-dependent pathway. Cytotoxic granules-mediated AICD was also detected in normal T lymphocytes though to a lesser extent. As expected, the cytotoxic granules-dependent AICD was abolished in T cells from Rab27a- or perforin-deficient patients who exhibited defective granules-dependent cytotoxicity. Supporting an in vivo relevance of the cytotoxic granules-dependent AICD in ALPS patients, we detected an increased number of circulating T lymphocytes expressing granzymes A and B. Altogether, these data indicated that the cytotoxic granules-dependent cell death in ALPS may compensate for Fas deficiency in T lymphocytes. Furthermore, they identified a novel AICD pathway as a unique alternative to Fas apoptosis in human peripheral T lymphocytes.


Assuntos
Apoptose , Ativação Linfocitária , Transtornos Linfoproliferativos/imunologia , Perforina/fisiologia , Linfócitos T/patologia , Receptor fas/deficiência , Doenças Autoimunes/imunologia , Estudos de Casos e Controles , Morte Celular , Células Cultivadas , Criança , Humanos , Tolerância Imunológica , Mutação , Receptores de Antígenos de Linfócitos T/metabolismo , Receptor fas/genética
20.
N Engl J Med ; 351(14): 1409-18, 2004 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-15459302

RESUMO

BACKGROUND: Impaired Fas-induced apoptosis of lymphocytes in vitro is a principal feature of the autoimmune lymphoproliferative syndrome (ALPS). We studied six children with ALPS whose lymphocytes had normal sensitivity to Fas-induced apoptosis in vitro. METHODS: Susceptibility to Fas-mediated apoptosis and the Fas gene were analyzed in purified subgroups of T cells and other mononuclear cells from six patients with ALPS type III. RESULTS: Heterozygous dominant Fas mutations were detected in the polyclonal double-negative T cells from all six patients. In two patients, these mutations were found in a fraction of CD4+ and CD8+ T cells, monocytes, and CD34+ hematopoietic precursors, but not in hair or mucosal epithelial cells. CONCLUSIONS: Somatic heterozygous mutations of Fas can cause a sporadic form of ALPS by allowing lymphoid precursors to resist the normal process of cell death.


Assuntos
Doenças Autoimunes/genética , Transtornos Linfoproliferativos/genética , Mutação , Receptor fas/genética , Adolescente , Apoptose , Doenças Autoimunes/classificação , Células Cultivadas , Criança , Análise Mutacional de DNA , Feminino , Expressão Gênica , Hematopoese/genética , Hematopoese/fisiologia , Heterozigoto , Humanos , Transtornos Linfoproliferativos/classificação , Masculino , Mosaicismo , Fenótipo , Reação em Cadeia da Polimerase , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T
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