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1.
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.

2.
Front Immunol ; 9: 2944, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30619304

RESUMO

CARD11 is a lymphocyte-specific scaffold molecule required for proper activation of B- and T-cells in response to antigen. Germline gain-of-function (GOF) mutations in the CARD11 gene cause a unique B cell lymphoproliferative disorder known as B cell Expansion with NF-κB and T cell Anergy (BENTA). In contrast, patients carrying loss-of-function (LOF), dominant negative (DN) CARD11 mutations present with severe atopic disease. Interestingly, both GOF and DN CARD11 variants cause primary immunodeficiency, with recurrent bacterial and viral infections, likely resulting from impaired adaptive immune responses. This report describes a unique four-generation family harboring a novel heterozygous germline indel mutation in CARD11 (c.701-713delinsT), leading to one altered amino acid and a deletion of 4 others (p.His234_Lys238delinsLeu). Strikingly, affected members exhibit both moderate B cell lymphocytosis and atopic dermatitis/allergies. Ectopic expression of this CARD11 variant stimulated constitutive NF-κB activity in T cell lines, similar to other BENTA patient mutations. However, unlike other GOF mutants, this variant significantly impeded the ability of wild-type CARD11 to induce NF-κB activation following antigen receptor ligation. Patient lymphocytes display marked intrinsic defects in B cell differentiation and reduced T cell responsiveness in vitro. Collectively, these data imply that a single heterozygous CARD11 mutation can convey both GOF and DN signaling effects, manifesting in a blended BENTA phenotype with atopic features. Our findings further emphasize the importance of balanced CARD11 signaling for normal immune responses.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/genética , Mutação com Ganho de Função , Mutação em Linhagem Germinativa , Guanilato Ciclase/genética , Síndromes de Imunodeficiência/genética , Transtornos Linfoproliferativos/genética , Linfócitos B/imunologia , Linfócitos B/metabolismo , Sequência de Bases , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Saúde da Família , Feminino , Guanilato Ciclase/metabolismo , Humanos , Síndromes de Imunodeficiência/metabolismo , Síndromes de Imunodeficiência/patologia , Lactente , Transtornos Linfoproliferativos/patologia , Masculino , NF-kappa B/metabolismo , Linhagem , Linfócitos T/imunologia , Linfócitos T/metabolismo
4.
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
5.
N Engl J Med ; 377(1): 52-61, 2017 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-28657829

RESUMO

BACKGROUND: Studies of monogenic gastrointestinal diseases have revealed molecular pathways critical to gut homeostasis and enabled the development of targeted therapies. METHODS: We studied 11 patients with abdominal pain and diarrhea caused by early-onset protein-losing enteropathy with primary intestinal lymphangiectasia, edema due to hypoproteinemia, malabsorption, and less frequently, bowel inflammation, recurrent infections, and angiopathic thromboembolic disease; the disorder followed an autosomal recessive pattern of inheritance. Whole-exome sequencing was performed to identify gene variants. We evaluated the function of CD55 in patients' cells, which we confirmed by means of exogenous induction of expression of CD55. RESULTS: We identified homozygous loss-of-function mutations in the gene encoding CD55 (decay-accelerating factor), which lead to loss of protein expression. Patients' T lymphocytes showed increased complement activation causing surface deposition of complement and the generation of soluble C5a. Costimulatory function and cytokine modulation by CD55 were defective. Genetic reconstitution of CD55 or treatment with a complement-inhibitory therapeutic antibody reversed abnormal complement activation. CONCLUSIONS: CD55 deficiency with hyperactivation of complement, angiopathic thrombosis, and protein-losing enteropathy (the CHAPLE syndrome) is caused by abnormal complement activation due to biallelic loss-of-function mutations in CD55. (Funded by the National Institute of Allergy and Infectious Diseases and others.).


Assuntos
Antígenos CD55/genética , Ativação do Complemento/genética , Proteínas do Sistema Complemento/metabolismo , Mutação , Enteropatias Perdedoras de Proteínas/genética , Trombose/genética , Antígenos CD55/sangue , Criança , Pré-Escolar , Ativação do Complemento/efeitos dos fármacos , Inativadores do Complemento/farmacologia , Feminino , Homozigoto , Humanos , Imunoglobulina A/sangue , Lactente , Intestino Delgado/patologia , Masculino , Linhagem , Enteropatias Perdedoras de Proteínas/complicações , Estatísticas não Paramétricas , Síndrome , Linfócitos T/metabolismo
6.
Nat Genet ; 49(8): 1192-1201, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28628108

RESUMO

Few monogenic causes for severe manifestations of common allergic diseases have been identified. Through next-generation sequencing on a cohort of patients with severe atopic dermatitis with and without comorbid infections, we found eight individuals, from four families, with novel heterozygous mutations in CARD11, which encodes a scaffolding protein involved in lymphocyte receptor signaling. Disease improved over time in most patients. Transfection of mutant CARD11 expression constructs into T cell lines demonstrated both loss-of-function and dominant-interfering activity upon antigen receptor-induced activation of nuclear factor-κB and mammalian target of rapamycin complex 1 (mTORC1). Patient T cells had similar defects, as well as low production of the cytokine interferon-γ (IFN-γ). The mTORC1 and IFN-γ production defects were partially rescued by supplementation with glutamine, which requires CARD11 for import into T cells. Our findings indicate that a single hypomorphic mutation in CARD11 can cause potentially correctable cellular defects that lead to atopic dermatitis.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/genética , Dermatite Atópica/genética , Mutação em Linhagem Germinativa , Guanilato Ciclase/genética , Sistema ASC de Transporte de Aminoácidos/metabolismo , Estudos de Coortes , Análise Mutacional de DNA , Dermatite Atópica/imunologia , Feminino , Genes Dominantes , Glutamina/metabolismo , Humanos , Células Jurkat , Ativação Linfocitária , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina , Antígenos de Histocompatibilidade Menor/metabolismo , Complexos Multiproteicos/metabolismo , NF-kappa B/metabolismo , Linhagem , Linfócitos T/imunologia , Linfócitos T/metabolismo , Serina-Treonina Quinases TOR/metabolismo
8.
J Exp Med ; 214(1): 91-106, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28011864

RESUMO

In this study, we describe four patients from two unrelated families of different ethnicities with a primary immunodeficiency, predominantly manifesting as susceptibility to Epstein-Barr virus (EBV)-related diseases. Three patients presented with EBV-associated Hodgkin's lymphoma and hypogammaglobulinemia; one also had severe varicella infection. The fourth had viral encephalitis during infancy. Homozygous frameshift or in-frame deletions in CD70 in these patients abolished either CD70 surface expression or binding to its cognate receptor CD27. Blood lymphocyte numbers were normal, but the proportions of memory B cells and EBV-specific effector memory CD8+ T cells were reduced. Furthermore, although T cell proliferation was normal, in vitro-generated EBV-specific cytotoxic T cell activity was reduced because of CD70 deficiency. This reflected impaired activation by, rather than effects during killing of, EBV-transformed B cells. Notably, expression of 2B4 and NKG2D, receptors implicated in controlling EBV infection, on memory CD8+ T cells from CD70-deficient individuals was reduced, consistent with their impaired killing of EBV-infected cells. Thus, autosomal recessive CD70 deficiency is a novel cause of combined immunodeficiency and EBV-associated diseases, reminiscent of inherited CD27 deficiency. Overall, human CD70-CD27 interactions therefore play a nonredundant role in T and B cell-mediated immunity, especially for protection against EBV and humoral immunity.


Assuntos
Linfócitos B/imunologia , Ligante CD27/deficiência , Infecções por Vírus Epstein-Barr/complicações , Doença de Hodgkin/etiologia , Síndromes de Imunodeficiência/complicações , Adolescente , Adulto , Ligante CD27/genética , Linfócitos T CD8-Positivos/imunologia , Criança , Citotoxicidade Imunológica , Feminino , Herpesvirus Humano 4/imunologia , Humanos , Memória Imunológica , Masculino , Mutação , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/fisiologia
9.
Science ; 349(6246): 436-40, 2015 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-26206937

RESUMO

Mutations in the LRBA gene (encoding the lipopolysaccharide-responsive and beige-like anchor protein) cause a syndrome of autoimmunity, lymphoproliferation, and humoral immune deficiency. The biological role of LRBA in immunologic disease is unknown. We found that patients with LRBA deficiency manifested a dramatic and sustained improvement in response to abatacept, a CTLA4 (cytotoxic T lymphocyte antigen-4)-immunoglobulin fusion drug. Clinical responses and homology of LRBA to proteins controlling intracellular trafficking led us to hypothesize that it regulates CTLA4, a potent inhibitory immune receptor. We found that LRBA colocalized with CTLA4 in endosomal vesicles and that LRBA deficiency or knockdown increased CTLA4 turnover, which resulted in reduced levels of CTLA4 protein in FoxP3(+) regulatory and activated conventional T cells. In LRBA-deficient cells, inhibition of lysosome degradation with chloroquine prevented CTLA4 loss. These findings elucidate a mechanism for CTLA4 trafficking and control of immune responses and suggest therapies for diseases involving the CTLA4 pathway.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Doenças Autoimunes/tratamento farmacológico , Antígeno CTLA-4/deficiência , Imunodeficiência de Variável Comum/tratamento farmacológico , Imunoconjugados/uso terapêutico , Abatacepte , Proteínas Adaptadoras de Transdução de Sinal/genética , Adolescente , Doenças Autoimunes/metabolismo , Antígeno CTLA-4/genética , Criança , Cloroquina/farmacologia , Imunodeficiência de Variável Comum/metabolismo , Endossomos/metabolismo , Feminino , Fatores de Transcrição Forkhead/análise , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Doenças Pulmonares Intersticiais/tratamento farmacológico , Doenças Pulmonares Intersticiais/metabolismo , Ativação Linfocitária , Lisossomos/metabolismo , Masculino , Proteólise , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Adulto Jovem
11.
Cell ; 159(7): 1578-90, 2014 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-25525876

RESUMO

Proteasomes and lysosomes constitute the major cellular systems that catabolize proteins to recycle free amino acids for energy and new protein synthesis. Tripeptidyl peptidase II (TPPII) is a large cytosolic proteolytic complex that functions in tandem with the proteasome-ubiquitin protein degradation pathway. We found that autosomal recessive TPP2 mutations cause recurrent infections, autoimmunity, and neurodevelopmental delay in humans. We show that a major function of TPPII in mammalian cells is to maintain amino acid levels and that TPPII-deficient cells compensate by increasing lysosome number and proteolytic activity. However, the overabundant lysosomes derange cellular metabolism by consuming the key glycolytic enzyme hexokinase-2 through chaperone-mediated autophagy. This reduces glycolysis and impairs the production of effector cytokines, including IFN-γ and IL-1ß. Thus, TPPII controls the balance between intracellular amino acid availability, lysosome number, and glycolysis, which is vital for adaptive and innate immunity and neurodevelopmental health.


Assuntos
Imunidade Adaptativa , Aminopeptidases/metabolismo , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Glicólise , Imunidade Inata , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/metabolismo , Proteólise , Serina Endopeptidases/metabolismo , Sequência de Aminoácidos , Aminopeptidases/química , Animais , Dipeptidil Peptidases e Tripeptidil Peptidases/química , Feminino , Humanos , Síndromes de Imunodeficiência/imunologia , Lisossomos/metabolismo , Masculino , Modelos Moleculares , Dados de Sequência Molecular , Linhagem , Alinhamento de Sequência , Serina Endopeptidases/química
12.
J Exp Med ; 211(13): 2549-66, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25422492

RESUMO

DOCK8 mutations result in an inherited combined immunodeficiency characterized by increased susceptibility to skin and other infections. We show that when DOCK8-deficient T and NK cells migrate through confined spaces, they develop cell shape and nuclear deformation abnormalities that do not impair chemotaxis but contribute to a distinct form of catastrophic cell death we term cytothripsis. Such defects arise during lymphocyte migration in collagen-dense tissues when DOCK8, through CDC42 and p21-activated kinase (PAK), is unavailable to coordinate cytoskeletal structures. Cytothripsis of DOCK8-deficient cells prevents the generation of long-lived skin-resident memory CD8 T cells, which in turn impairs control of herpesvirus skin infections. Our results establish that DOCK8-regulated shape integrity of lymphocytes prevents cytothripsis and promotes antiviral immunity in the skin.


Assuntos
Forma Celular/imunologia , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Imunidade , Células Matadoras Naturais/patologia , Pele/imunologia , Pele/virologia , Linfócitos T/patologia , Animais , Apoptose/efeitos dos fármacos , Bovinos , Adesão Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/patologia , Forma Celular/efeitos dos fármacos , Quimiocina CXCL12/farmacologia , Quimiotaxia/efeitos dos fármacos , Colágeno/farmacologia , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Feminino , Fatores de Troca do Nucleotídeo Guanina/deficiência , Humanos , Imunidade/efeitos dos fármacos , Memória Imunológica/efeitos dos fármacos , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais/efeitos dos fármacos , Pele/efeitos dos fármacos , Pele/patologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Proteína cdc42 de Ligação ao GTP/metabolismo , Quinases Ativadas por p21/metabolismo
13.
J Allergy Clin Immunol ; 133(6): 1667-75, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24797421

RESUMO

BACKGROUND: Autosomal recessive loss-of-function mutations in dedicator of cytokinesis 8 (DOCK8) cause a combined immunodeficiency characterized by atopy, recurrent infections, and cancer susceptibility. A genotype-phenotype explanation for the variable disease expression is lacking. OBJECTIVE: We investigated whether reversions contributed to the variable disease expression. METHODS: Patients followed at the National Institutes of Health's Clinical Center were studied. We performed detailed genetic analyses and intracellular flow cytometry to detect DOCK8 protein expression within lymphocyte subsets. RESULTS: We identified 17 of 34 DOCK8-deficient patients who had germline mutations with variable degrees of reversion caused by somatic repair. Somatic repair of the DOCK8 mutations resulted from second-site mutation, original-site mutation, gene conversion, and intragenic crossover. Higher degrees of reversion were associated with recombination-mediated repair. DOCK8 expression was restored primarily within antigen-experienced T cells or natural killer cells but less so in naive T or B cells. Several patients exhibited multiple different repair events. Patients who had reversions were older and had less severe allergic disease, although infection susceptibility persisted. No patients were cured without hematopoietic cell transplantation. CONCLUSIONS: In patients with DOCK8 deficiency, only certain combinations of germline mutations supported secondary somatic repair. Those patients had an ameliorated disease course with longer survival but still had fatal complications or required hematopoietic cell transplantation. These observations support the concept that some DOCK8-immunodeficient patients have mutable mosaic genomes that can modulate disease phenotype over time.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/genética , Síndromes de Imunodeficiência/genética , Mutação , Fenótipo , Adolescente , Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/metabolismo , Criança , Pré-Escolar , Análise Mutacional de DNA , Reparo do DNA , Genótipo , Mutação em Linhagem Germinativa , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Humanos , Síndromes de Imunodeficiência/diagnóstico , Síndromes de Imunodeficiência/mortalidade , Imunofenotipagem , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo
14.
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
15.
Science ; 341(6142): 186-91, 2013 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-23846901

RESUMO

The magnesium transporter 1 (MAGT1) is a critical regulator of basal intracellular free magnesium (Mg(2+)) concentrations. Individuals with genetic deficiencies in MAGT1 have high levels of Epstein-Barr virus (EBV) and a predisposition to lymphoma. We show that decreased intracellular free Mg(2+) causes defective expression of the natural killer activating receptor NKG2D in natural killer (NK) and CD8(+) T cells and impairs cytolytic responses against EBV. Notably, magnesium supplementation in MAGT1-deficient patients restores intracellular free Mg(2+) and NKG2D while concurrently reducing EBV-infected cells in vivo, demonstrating a link between NKG2D cytolytic activity and EBV antiviral immunity in humans. Moreover, these findings reveal a specific molecular function of free basal intracellular Mg(2+) in eukaryotic cells.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Citotoxicidade Imunológica , Infecções por Vírus Epstein-Barr/imunologia , Células Matadoras Naturais/imunologia , Deficiência de Magnésio/imunologia , Magnésio/imunologia , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Humanos , Subfamília K de Receptores Semelhantes a Lectina de Células NK/genética , Doenças por Imunodeficiência Combinada Ligada ao Cromossomo X/imunologia
16.
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
17.
J Clin Immunol ; 32(4): 698-708, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22476911

RESUMO

We describe seven Turkish children with DOCK8 deficiency who have not been previously reported. Three patients presented with typical features of recurrent or severe cutaneous viral infections, atopic dermatitis, and recurrent respiratory or gastrointestinal tract infections. However, four patients presented with other features. Patient 1-1 featured sclerosing cholangitis and colitis; patient 2-1, granulomatous soft tissue lesion and central nervous system involvement, with primary central nervous system lymphoma found on follow-up; patient 3-1, a fatal metastatic leiomyosarcoma; and patient 4-2 showed no other symptoms initially besides atopic dermatitis. Similar to other previously reported Turkish patients, but in contrast to patients of non-Turkish ethnicity, the patients' lymphopenia was primarily restricted to CD4(+) T cells. Patients had homozygous mutations in DOCK8 that altered splicing, introduced premature terminations, destabilized protein, or involved large deletions within the gene. Genotyping of remaining family members showed that DOCK8 deficiency is a fully penetrant, autosomal recessive disease. In our patients, bone marrow transplantation resulted in rapid improvement followed by disappearance of viral skin lesions, including lesions resembling epidermodysplasia verruciformis, atopic dermatitis, and recurrent infections. Particularly for patients who feature unusual clinical manifestations, immunological testing, in conjunction with genetic testing, can prove invaluable in diagnosing DOCK8 deficiency and providing potentially curative treatment.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Fatores de Troca do Nucleotídeo Guanina/deficiência , Fatores de Troca do Nucleotídeo Guanina/genética , Imunodeficiência Combinada Severa/genética , Adolescente , Transplante de Medula Óssea , Criança , Pré-Escolar , Dermatite Atópica/genética , Feminino , Genótipo , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Linfopenia/genética , Linfopenia/terapia , Masculino , Deleção de Sequência , Imunodeficiência Combinada Severa/imunologia , Imunodeficiência Combinada Severa/terapia , Turquia
18.
Nature ; 475(7357): 471-6, 2011 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-21796205

RESUMO

The magnesium ion, Mg(2+), is essential for all life as a cofactor for ATP, polyphosphates such as DNA and RNA, and metabolic enzymes, but whether it plays a part in intracellular signalling (as Ca(2+) does) is unknown. Here we identify mutations in the magnesium transporter gene, MAGT1, in a novel X-linked human immunodeficiency characterized by CD4 lymphopenia, severe chronic viral infections, and defective T-lymphocyte activation. We demonstrate that a rapid transient Mg(2+) influx is induced by antigen receptor stimulation in normal T cells and by growth factor stimulation in non-lymphoid cells. MAGT1 deficiency abrogates the Mg(2+) influx, leading to impaired responses to antigen receptor engagement, including defective activation of phospholipase Cγ1 and a markedly impaired Ca(2+) influx in T cells but not B cells. These observations reveal a role for Mg(2+) as an intracellular second messenger coupling cell-surface receptor activation to intracellular effectors and identify MAGT1 as a possible target for novel therapeutics.


Assuntos
Magnésio/imunologia , Sistemas do Segundo Mensageiro/imunologia , Linfócitos T/imunologia , T-Linfocitopenia Idiopática CD4-Positiva/imunologia , Cálcio/imunologia , Proteínas de Transporte de Cátions/genética , Feminino , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Masculino , Fosfolipase C gama/genética , Fosfolipase C gama/metabolismo , T-Linfocitopenia Idiopática CD4-Positiva/genética
19.
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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