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1.
J Exp Med ; 214(7): 1949-1972, 2017 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-28606988

RESUMO

MDA5 is a cytosolic sensor of double-stranded RNA (ds)RNA including viral byproducts and intermediates. We studied a child with life-threatening, recurrent respiratory tract infections, caused by viruses including human rhinovirus (HRV), influenza virus, and respiratory syncytial virus (RSV). We identified in her a homozygous missense mutation in IFIH1 that encodes MDA5. Mutant MDA5 was expressed but did not recognize the synthetic MDA5 agonist/(ds)RNA mimic polyinosinic-polycytidylic acid. When overexpressed, mutant MDA5 failed to drive luciferase activity from the IFNB1 promoter or promoters containing ISRE or NF-κB sequence motifs. In respiratory epithelial cells or fibroblasts, wild-type but not knockdown of MDA5 restricted HRV infection while increasing IFN-stimulated gene expression and IFN-ß/λ. However, wild-type MDA5 did not restrict influenza virus or RSV replication. Moreover, nasal epithelial cells from the patient, or fibroblasts gene-edited to express mutant MDA5, showed increased replication of HRV but not influenza or RSV. Thus, human MDA5 deficiency is a novel inborn error of innate and/or intrinsic immunity that causes impaired (ds)RNA sensing, reduced IFN induction, and susceptibility to the common cold virus.


Assuntos
Helicase IFIH1 Induzida por Interferon/genética , Mutação , Infecções por Picornaviridae/genética , Infecções por Picornaviridae/virologia , Rhinovirus/fisiologia , Antivirais/farmacologia , Sequência de Bases , Células Cultivadas , Pré-Escolar , Análise Mutacional de DNA/métodos , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/virologia , Expressão Gênica/efeitos dos fármacos , Genes Recessivos/genética , Heterozigoto , Homozigoto , Interações Hospedeiro-Patógeno , Humanos , Helicase IFIH1 Induzida por Interferon/deficiência , Interferons/farmacologia , Masculino , Linhagem
2.
J Allergy Clin Immunol ; 133(5): 1400-9, 1409.e1-5, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24589341

RESUMO

BACKGROUND: Identifying genetic syndromes that lead to significant atopic disease can open new pathways for investigation and intervention in allergy. OBJECTIVE: We sought to define a genetic syndrome of severe atopy, increased serum IgE levels, immune deficiency, autoimmunity, and motor and neurocognitive impairment. METHODS: Eight patients from 2 families with similar syndromic features were studied. Thorough clinical evaluations, including brain magnetic resonance imaging and sensory evoked potentials, were performed. Peripheral lymphocyte flow cytometry, antibody responses, and T-cell cytokine production were measured. Whole-exome sequencing was performed to identify disease-causing mutations. Immunoblotting, quantitative RT-PCR, enzymatic assays, nucleotide sugar, and sugar phosphate analyses, along with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry of glycans, were used to determine the molecular consequences of the mutations. RESULTS: Marked atopy and autoimmunity were associated with increased T(H)2 and T(H)17 cytokine production by CD4(+) T cells. Bacterial and viral infection susceptibility were noted along with T-cell lymphopenia, particularly of CD8(+) T cells, and reduced memory B-cell numbers. Apparent brain hypomyelination resulted in markedly delayed evoked potentials and likely contributed to neurologic abnormalities. Disease segregated with novel autosomal recessive mutations in a single gene, phosphoglucomutase 3 (PGM3). Although PGM3 protein expression was variably diminished, impaired function was demonstrated by decreased enzyme activity and reduced uridine diphosphate-N-acetyl-D-glucosamine, along with decreased O- and N-linked protein glycosylation in patients' cells. These results define a new congenital disorder of glycosylation. CONCLUSIONS: Autosomal recessive hypomorphic PGM3 mutations underlie a disorder of severe atopy, immune deficiency, autoimmunity, intellectual disability, and hypomyelination.


Assuntos
Doenças Autoimunes/genética , Transtornos Cognitivos/genética , Imunodeficiência de Variável Comum/genética , Doenças Genéticas Inatas/genética , Hipersensibilidade/genética , Mutação , Fosfoglucomutase/genética , Doenças Autoimunes/enzimologia , Doenças Autoimunes/imunologia , Doenças Autoimunes/patologia , Linfócitos B/enzimologia , Linfócitos B/imunologia , Linfócitos B/patologia , Linfócitos T CD8-Positivos/enzimologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Criança , Pré-Escolar , Transtornos Cognitivos/enzimologia , Transtornos Cognitivos/imunologia , Transtornos Cognitivos/patologia , Imunodeficiência de Variável Comum/enzimologia , Imunodeficiência de Variável Comum/imunologia , Imunodeficiência de Variável Comum/patologia , Família , Feminino , Doenças Genéticas Inatas/enzimologia , Doenças Genéticas Inatas/imunologia , Doenças Genéticas Inatas/patologia , Humanos , Hipersensibilidade/enzimologia , Hipersensibilidade/imunologia , Hipersensibilidade/patologia , Imunoglobulina E/genética , Imunoglobulina E/imunologia , Masculino , Linhagem , Fosfoglucomutase/imunologia , Fosfoglucomutase/metabolismo , Células Th17/enzimologia , Células Th17/imunologia , Células Th17/patologia , Células Th2/enzimologia , Células Th2/imunologia , Células Th2/patologia , Adulto Jovem
3.
J Exp Med ; 209(12): 2247-61, 2012 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-23129749

RESUMO

Nuclear factor-κB (NF-κB) controls genes involved in normal lymphocyte functions, but constitutive NF-κB activation is often associated with B cell malignancy. Using high-throughput whole transcriptome sequencing, we investigated a unique family with hereditary polyclonal B cell lymphocytosis. We found a novel germline heterozygous missense mutation (E127G) in affected patients in the gene encoding CARD11, a scaffolding protein required for antigen receptor (AgR)-induced NF-κB activation in both B and T lymphocytes. We subsequently identified a second germline mutation (G116S) in an unrelated, phenotypically similar patient, confirming mutations in CARD11 drive disease. Like somatic, gain-of-function CARD11 mutations described in B cell lymphoma, these germline CARD11 mutants spontaneously aggregate and drive constitutive NF-κB activation. However, these CARD11 mutants rendered patient T cells less responsive to AgR-induced activation. By reexamining this rare genetic disorder first reported four decades ago, our findings provide new insight into why activating CARD11 mutations may induce B cell expansion and preferentially predispose to B cell malignancy without dramatically perturbing T cell homeostasis.


Assuntos
Linfócitos B/metabolismo , Proteínas Adaptadoras de Sinalização CARD/genética , Predisposição Genética para Doença/genética , Guanilato Ciclase/genética , Linfocitose/genética , Sequência de Bases , Análise por Conglomerados , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Perfilação da Expressão Gênica , Mutação em Linhagem Germinativa/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Immunoblotting , Linfocitose/complicações , Microscopia Confocal , Dados de Sequência Molecular , Mutação de Sentido Incorreto/genética , NF-kappa B/metabolismo , Linhagem , Esplenomegalia/complicações
4.
Blood ; 119(23): 5575-83, 2012 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-22496155

RESUMO

FoxP3(+) regulatory T cells (Tregs) suppress GVHD while preserving graft-versus-tumor effects, making them an attractive target for GVHD therapy. The donor-derived Treg pool can potentially be derived from the expansion of preexisting natural Tregs (nTregs) or from de novo generation of inducible Tregs (iTregs) from donor Tconvs in the transplantation recipient. Using an MHC-mismatched model of acute GVHD, in the present study we found that the Treg pool was comprised equally of donor-derived nTregs and iTregs. Experiments using various combinations of T cells from wild-type and FoxP3-deficient mice suggested that both preexisting donor nTregs and the generation of iTregs in the recipient mice contribute to protection against GVHD. Surprisingly, CD8(+)FoxP3(+) T cells represented approximately 70% of the iTreg pool. These CD8(+)FoxP3(+) T cells shared phenotypic markers with their CD4(+) counterparts and displayed suppressive activity, suggesting that they were bona fide iTregs. Both CD4(+) and CD8(+) Tregs appeared to be protective against GVHD-induced lethality and required IL-2 and TGFß receptor expression for their generation. These data illustrate the complex makeup of the donor-derived FoxP3(+) Treg pool in allogeneic recipients and their potential role in protection against GVHD.


Assuntos
Antígenos CD4/imunologia , Linfócitos T CD4-Positivos/imunologia , Antígenos CD8/imunologia , Linfócitos T CD8-Positivos/imunologia , Doença Enxerto-Hospedeiro/imunologia , Receptores de Interleucina-2/imunologia , Receptores de Fatores de Crescimento Transformadores beta/imunologia , Animais , Fatores de Transcrição Forkhead/imunologia , Camundongos , Camundongos Endogâmicos C57BL
5.
N Engl J Med ; 361(21): 2046-55, 2009 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-19776401

RESUMO

BACKGROUND: Recurrent sinopulmonary and cutaneous viral infections with elevated serum levels of IgE are features of some variants of combined immunodeficiency. The genetic causes of these variants are unknown. METHODS: We collected longitudinal clinical data on 11 patients from eight families who had recurrent sinopulmonary and cutaneous viral infections. We performed comparative genomic hybridization arrays and targeted gene sequencing. Variants with predicted loss-of-expression mutations were confirmed by means of a quantitative reverse-transcriptase-polymerase-chain-reaction assay and immunoblotting. We evaluated the number and function of lymphocytes with the use of in vitro assays and flow cytometry. RESULTS: Patients had recurrent otitis media, sinusitis, and pneumonias; recurrent Staphylococcus aureus skin infections with otitis externa; recurrent, severe herpes simplex virus or herpes zoster infections; extensive and persistent infections with molluscum contagiosum; and human papillomavirus infections. Most patients had severe atopy with anaphylaxis; several had squamous-cell carcinomas, and one had T-cell lymphoma-leukemia. Elevated serum IgE levels, hypereosinophilia, low numbers of T cells and B cells, low serum IgM levels, and variable IgG antibody responses were common. Expansion in vitro of activated CD8 T cells was impaired. Novel homozygous or compound heterozygous deletions and point mutations in the gene encoding the dedicator of cytokinesis 8 protein (DOCK8) led to the absence of DOCK8 protein in lymphocytes. CONCLUSIONS: Autosomal recessive DOCK8 deficiency is associated with a novel variant of combined immunodeficiency.


Assuntos
Deleção de Genes , Fatores de Troca do Nucleotídeo Guanina/genética , Imunodeficiência Combinada Severa/genética , Linfócitos T CD8-Positivos/fisiologia , Feminino , Genes Recessivos , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Humanos , Imunoglobulinas/sangue , Estudos Longitudinais , Ativação Linfocitária , Masculino , Linhagem , Infecções Respiratórias/genética , Infecções Respiratórias/imunologia , Imunodeficiência Combinada Severa/imunologia , Dermatopatias Infecciosas/genética , Dermatopatias Infecciosas/imunologia
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