Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 59
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Clin Invest ; 130(1): 507-522, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31714901

RESUMO

X-linked immunodeficiency with magnesium defect, EBV infection, and neoplasia (XMEN) disease are caused by deficiency of the magnesium transporter 1 (MAGT1) gene. We studied 23 patients with XMEN, 8 of whom were EBV naive. We observed lymphadenopathy (LAD), cytopenias, liver disease, cavum septum pellucidum (CSP), and increased CD4-CD8-B220-TCRαß+ T cells (αßDNTs), in addition to the previously described features of an inverted CD4/CD8 ratio, CD4+ T lymphocytopenia, increased B cells, dysgammaglobulinemia, and decreased expression of the natural killer group 2, member D (NKG2D) receptor. EBV-associated B cell malignancies occurred frequently in EBV-infected patients. We studied patients with XMEN and patients with autoimmune lymphoproliferative syndrome (ALPS) by deep immunophenotyping (32 immune markers) using time-of-flight mass cytometry (CyTOF). Our analysis revealed that the abundance of 2 populations of naive B cells (CD20+CD27-CD22+IgM+HLA-DR+CXCR5+CXCR4++CD10+CD38+ and CD20+CD27-CD22+IgM+HLA-DR+CXCR5+CXCR4+CD10-CD38-) could differentially classify XMEN, ALPS, and healthy individuals. We also performed glycoproteomics analysis on T lymphocytes and show that XMEN disease is a congenital disorder of glycosylation that affects a restricted subset of glycoproteins. Transfection of MAGT1 mRNA enabled us to rescue proteins with defective glycosylation. Together, these data provide new clinical and pathophysiological foundations with important ramifications for the diagnosis and treatment of XMEN disease.

2.
iScience ; 23(1): 100759, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31887663

RESUMO

T lymphocytes are critical for effective immunity, and the ability to study their behavior in vitro can facilitate major insights into their development, function, and fate. However, the composition of human plasma differs from conventional media, and we hypothesized that such differences could impact immune cell physiology. Here, we showed that relative to the medium typically used to culture lymphocytes (RPMI), a physiologic medium (human plasma-like medium; HPLM) induced markedly different transcriptional responses in human primary T cells and in addition, improved their activation upon antigen stimulation. We found that this medium-dependent effect on T cell activation is linked to Ca2+, which is six-fold higher in HPLM than in RPMI. Thus, a medium that more closely resembles human plasma has striking effects on T cell biology, further demonstrates that medium composition can profoundly affect experimental results, and broadly suggests that physiologic media may offer a valuable way to study cultured immune cells.

3.
Curr Opin Pediatr ; 31(6): 815-820, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31693592

RESUMO

PURPOSE OF REVIEW: Studying primary immunodeficiencies (PIDs) provides insights into human antiviral immunity in the natural infectious environment. This review describes new PIDs with genetic defects that impair innate antiviral responses. RECENT FINDINGS: New genetic defects in the interferon (IFN) signaling pathway include IFNAR1 deficiency, which causes uncontrolled infections with measles-mumps-rubella or yellow fever vaccines, and possibly also cytomegalovirus (CMV); and IRF9 deficiency, which results in influenza virus susceptibility. Genetic defects in several pattern recognition receptors include MDA5 deficiency, which impairs viral RNA sensing and confers human rhinovirus susceptibility; RNA polymerase III haploinsufficiency, which impairs sensing of A:T-rich virus DNA and confers VZV susceptibility; and TLR3 deficiency, which causes HSV-1 encephalitis (HSE) or influenza virus pneumonitis. Defects in RNA metabolism, such as that caused by Debranching enzyme 1 deficiency, can cause virus meningoencephalitis. Finally, defects in host restriction factors for virus replication, such as in CIB1 deficiency, contribute to uncontrolled ß-HPV infections. SUMMARY: Several new PIDs highlight the role of type I/III IFN signaling pathway, virus sensors, and host virus restriction factors in human antiviral immunity.

4.
Curr Opin Pediatr ; 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31464763

RESUMO

PURPOSE OF REVIEW: Studying primary immunodeficiencies (PIDs) provides insights into human antiviral immunity in the natural infectious environment. This review describes new PIDs with genetic defects that impair innate antiviral responses. RECENT FINDINGS: New genetic defects in the interferon (IFN) signaling pathway include IFNAR1 deficiency, which causes uncontrolled infections with measles-mumps-rubella or yellow fever vaccines, and possibly also cytomegalovirus (CMV); and IRF9 deficiency, which results in influenza virus susceptibility. Genetic defects in several pattern recognition receptors include MDA5 deficiency, which impairs viral RNA sensing and confers human rhinovirus susceptibility; RNA polymerase III haploinsufficiency, which impairs sensing of A:T-rich virus DNA and confers VZV susceptibility; and TLR3 deficiency, which causes HSV-1 encephalitis (HSE) or influenza virus pneumonitis. Defects in RNA metabolism, such as that caused by Debranching enzyme 1 deficiency, can cause virus meningoencephalitis. Finally, defects in host restriction factors for virus replication, such as in CIB1 deficiency, contribute to uncontrolled ß-HPV infections. SUMMARY: Several new PIDs highlight the role of type I/III IFN signaling pathway, virus sensors, and host virus restriction factors in human antiviral immunity.

5.
J Clin Immunol ; 39(6): 592-595, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31267431

RESUMO

Mutations in Dedicator of cytokinesis 8 (DOCK8) are a rare cause of combined immunodeficiency associated with atopy, infectious susceptibility, and risk for malignancy. We describe a 22-year-old male with a diagnosis of B cell lymphoblastic leukemia followed by Epstein-Barr virus (EBV)-associated diffuse large B cell lymphoma (DLBCL) with compound heterozygous mutations in DOCK8 and normal intracellular DOCK8 protein expression. Here, B cell lymphoblastic leukemia followed by EBV-associated DLBCL led to the discovery of DOCK8 deficiency. For instances of high clinical suspicion despite normal DOCK8 protein expression, additional functional testing is critical to make a diagnosis. Understanding the spectrum of DOCK8 mutants and their phenotypes will improve our understanding of DOCK8 deficiency.

6.
Front Immunol ; 10: 1005, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31139182

RESUMO

Background: Mannose-binding lectin (MBL) is an innate immune protein with strong biologic plausibility for protecting against influenza virus-related sepsis and bacterial co-infection. In an autopsy cohort of 105 influenza-infected young people, carriage of the deleterious MBL gene MBL2_Gly54Asp("B") mutation was identified in 5 of 8 individuals that died from influenza-methicillin-resistant Staphylococcus aureus (MRSA) co-infection. We evaluated MBL2 variants known to influence MBL levels with pediatric influenza-related critical illness susceptibility and/or severity including with bacterial co-infections. Methods: We enrolled children and adolescents with laboratory-confirmed influenza infection across 38 pediatric intensive care units from November 2008 to June 2016. We sequenced MBL2 "low-producer" variants rs11003125("H/L"), rs7096206("Y/X"), rs1800450Gly54Asp("B"), rs1800451Gly57Glu("C"), rs5030737Arg52Cys("D") in patients and biologic parents. We measured serum levels and compared complement activity in low-producing homozygotes ("B/B," "C/C") to HYA/HYA controls. We used a population control of 1,142 healthy children and also analyzed family trios (PBAT/HBAT) to evaluate disease susceptibility, and nested case-control analyses to evaluate severity. Results: We genotyped 420 patients with confirmed influenza-related sepsis: 159 (38%) had acute lung injury (ALI), 165 (39%) septic shock, and 30 (7%) died. Although bacterial co-infection was diagnosed in 133 patients (32%), only MRSA co-infection (n = 33, 8% overall) was associated with death (p < 0.0001), present in 11 of 30 children that died (37%). MBL2 variants predicted serum levels and complement activation as expected. We found no association between influenza-related critical illness susceptibility and MBL2 variants using family trios (633 biologic parents) or compared to population controls. MBL2 variants were not associated with admission illness severity, septic shock, ALI, or bacterial co-infection diagnosis. Carriage of low-MBL producing MBL2 variants was not a risk factor for mortality, but children that died did have higher carriage of one or more B alleles (OR 2.3; p = 0.007), including 7 of 11 with influenza MRSA-related death (vs. 2 of 22 survivors: OR 14.5, p = 0.0002). Conclusions: MBL2 variants that decrease MBL levels were not associated with susceptibility to pediatric influenza-related critical illness or with multiple measures of critical illness severity. We confirmed a prior report of higher B allele carriage in a relatively small number of young individuals with influenza-MRSA associated death.

7.
JCI Insight ; 52019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31021819

RESUMO

Bi-allelic inactivating mutations in DOCK8 cause a combined immunodeficiency characterised by severe pathogen infections, eczema, allergies, malignancy and impaired humoral responses. These clinical features result from functional defects in most lymphocyte lineages. Thus, DOCK8 plays a key role in immune cell function. Hematopoietic stem cell transplantation (HSCT) is curative for DOCK8 deficiency. While previous reports have described clinical outcomes for DOCK8 deficiency following HSCT, the effect on lymphocyte reconstitution and function has not been investigated. Our study determined whether defects in lymphocyte differentiation and function in DOCK8-deficient patients were restored following HSCT. DOCK8-deficient T and B lymphocytes exhibited aberrant activation and effector function in vivo and in vitro. Frequencies of αß T and MAIT cells were reduced while γδT cells were increased in DOCK8-deficient patients. HSCT improved, abnormal lymphocyte function in DOCK8-deficient patients. Elevated total and allergen-specific IgE in DOCK8-deficient patients decreased over time following HSCT. Our results document the extensive catalogue of cellular defects in DOCK8-deficient patients, and the efficacy of HSCT to correct these defects, concurrent with improvements in clinical phenotypes. Overall, our findings provide mechanisms at a functional cellular level for improvements in clinical features of DOCK8 deficiency post-HSCT, identify biomarkers that correlate with improved clinical outcomes, and inform the general dynamics of immune reconstitution in patients with monogenic immune disorders following HSCT.

8.
J Allergy Clin Immunol Pract ; 7(3): 848-855, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30391550

RESUMO

BACKGROUND: Biallelic variations in the dedicator of cytokinesis 8 (DOCK8) gene cause a combined immunodeficiency with eczema, recurrent bacterial and viral infections, and malignancy. Natural disease outcome is dismal, but allogeneic hematopoietic stem cell transplantation (HSCT) can cure the disease. OBJECTIVE: To determine outcome of HSCT for DOCK8 deficiency and define possible outcome variables. METHODS: We performed a retrospective study of the results of HSCT in a large international cohort of DOCK8-deficient patients. RESULTS: We identified 81 patients from 22 centers transplanted at a median age of 9.7 years (range, 0.7-27.2 years) between 1995 and 2015. After median follow-up of 26 months (range, 3-135 months), 68 (84%) patients are alive. Severe acute (III-IV) or chronic graft versus host disease occurred in 11% and 10%, respectively. Causes of death were infections (n = 5), graft versus host disease (5), multiorgan failure (2), and preexistent lymphoma (1). Survival after matched related (n = 40) or unrelated (35) HSCT was 89% and 81%, respectively. Reduced-toxicity conditioning based on either treosulfan or reduced-dose busulfan resulted in superior survival compared with fully myeloablative busulfan-based regimens (97% vs 78%; P = .049). Ninety-six percent of patients younger than 8 years at HSCT survived, compared with 78% of those 8 years and older (P = .06). Of the 73 patients with chimerism data available, 65 (89%) had more than 90% donor T-cell chimerism at last follow-up. Not all disease manifestations responded equally well to HSCT: eczema, infections, and mollusca resolved quicker than food allergies or failure to thrive. CONCLUSIONS: HSCT is curative in most DOCK8-deficient patients, confirming this approach as the treatment of choice. HSCT using a reduced-toxicity regimen may offer the best chance for survival.

9.
Immunol Rev ; 287(1): 9-19, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30565250

RESUMO

DOCK8 immunodeficiency syndrome (DIDS) is a progressive combined immunodeficiency that can be distinguished from other combined immunodeficiencies or hyperimmunoglobulinemia E syndromes in featuring (a) profound susceptibility to virus infections of the skin, with associated skin cancers, and (b) severe food allergies. The DOCK8 locus has many repetitive sequence elements that predispose to the generation of large germline deletions as well as recombination-mediated somatic DNA repair. Residual DOCK8 protein contributes to the variable disease phenotype. The severe virus infections of the skin, and probably also VZV-associated vasculopathy, reflect an important function of DOCK8, which is normally required to maintain lymphocyte shape integrity as the cells migrate through dense tissues. Loss of DOCK8 also causes immune deficits through other mechanisms including a milder generalized cell survival defect and skewing of T helper cell subsets. Recent work has uncovered the roles for DOCK8 in dendritic cell responses that can also help explain the virus susceptibility, as well as in regulatory T cells that might help explain autoimmunity in a minority of patients. Fortunately, hematopoietic stem cell transplantation cures the eczema and infection susceptibility of DIDS, but not necessarily the other disease manifestations including food allergies.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/genética , Síndromes de Imunodeficiência/imunologia , Linfócitos T/imunologia , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Suscetibilidade a Doenças , Eczema , Terapia Genética , Transplante de Células-Tronco Hematopoéticas , Humanos , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/terapia , Neoplasias de Células Escamosas , Pneumonia , Vasculite do Sistema Nervoso Central
10.
Nat Med ; 24(12): 1815-1821, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30397357

RESUMO

Human microbiome studies have revealed the intricate interplay of host immunity and bacterial communities to achieve homeostatic balance. Healthy skin microbial communities are dominated by bacteria with low viral representation1-3, mainly bacteriophage. Specific eukaryotic viruses have been implicated in both common and rare skin diseases, but cataloging skin viral communities has been limited. Alterations in host immunity provide an opportunity to expand our understanding of microbial-host interactions. Primary immunodeficient patients manifest with various viral, bacterial, fungal, and parasitic infections, including skin infections4. Dedicator of cytokinesis 8 (DOCK8) deficiency is a rare primary human immunodeficiency characterized by recurrent cutaneous and systemic infections, as well as atopy and cancer susceptibility5. DOCK8, encoding a guanine nucleotide exchange factor highly expressed in lymphocytes, regulates actin cytoskeleton, which is critical for migration through collagen-dense tissues such as skin6. Analyzing deep metagenomic sequencing data from DOCK8-deficient skin samples demonstrated a notable increase in eukaryotic viral representation and diversity compared with healthy volunteers. De novo assembly approaches identified hundreds of novel human papillomavirus genomes, illuminating microbial dark matter. Expansion of the skin virome in DOCK8-deficient patients underscores the importance of immune surveillance in controlling eukaryotic viral colonization and infection.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/genética , Síndromes de Imunodeficiência/virologia , Dermatopatias/virologia , Pele/virologia , Adolescente , Bacteriófagos/genética , Criança , Feminino , Genoma Viral/genética , Fatores de Troca do Nucleotídeo Guanina/deficiência , Voluntários Saudáveis , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/imunologia , Humanos , Imunidade/genética , Síndromes de Imunodeficiência/microbiologia , Síndromes de Imunodeficiência/patologia , Linfócitos/virologia , Masculino , Metagenoma/genética , Metagenoma/imunologia , Microbiota/genética , Papillomaviridae/isolamento & purificação , Papillomaviridae/patogenicidade , Pele/microbiologia , Dermatopatias/genética , Dermatopatias/microbiologia , Dermatopatias/patologia
11.
J Exp Med ; 215(10): 2567-2585, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30143481

RESUMO

Life-threatening pulmonary influenza can be caused by inborn errors of type I and III IFN immunity. We report a 5-yr-old child with severe pulmonary influenza at 2 yr. She is homozygous for a loss-of-function IRF9 allele. Her cells activate gamma-activated factor (GAF) STAT1 homodimers but not IFN-stimulated gene factor 3 (ISGF3) trimers (STAT1/STAT2/IRF9) in response to IFN-α2b. The transcriptome induced by IFN-α2b in the patient's cells is much narrower than that of control cells; however, induction of a subset of IFN-stimulated gene transcripts remains detectable. In vitro, the patient's cells do not control three respiratory viruses, influenza A virus (IAV), parainfluenza virus (PIV), and respiratory syncytial virus (RSV). These phenotypes are rescued by wild-type IRF9, whereas silencing IRF9 expression in control cells increases viral replication. However, the child has controlled various common viruses in vivo, including respiratory viruses other than IAV. Our findings show that human IRF9- and ISGF3-dependent type I and III IFN responsive pathways are essential for controlling IAV.


Assuntos
Alelos , Homozigoto , Influenza Humana , Fator Gênico 3 Estimulado por Interferon, Subunidade gama/deficiência , Orthomyxoviridae/imunologia , Pneumonia Viral , Feminino , Humanos , Lactente , Influenza Humana/genética , Influenza Humana/imunologia , Influenza Humana/patologia , Interferon alfa-2/genética , Interferon alfa-2/imunologia , Fator Gênico 3 Estimulado por Interferon, Subunidade gama/imunologia , Pneumonia Viral/genética , Pneumonia Viral/imunologia , Pneumonia Viral/patologia
13.
Front Immunol ; 9: 198, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29472930

RESUMO

B-cell expansion with NF-κB and T-cell anergy (BENTA) disease is a B-cell-specific lymphoproliferative disorder caused by germline gain-of-function mutations in CARD11. These mutations force the CARD11 scaffold into an open conformation capable of stimulating constitutive NF-κB activation in lymphocytes, without requiring antigen receptor engagement. Many BENTA patients also suffer from recurrent infections, with 7 out of 16 patients exhibiting chronic, low-grade Epstein-Barr virus (EBV) viremia. In this mini-review, we discuss EBV infection in the pathogenesis and clinical management of BENTA disease, and speculate on mechanisms that could explain inadequate control of viral infection in BENTA patients.


Assuntos
Linfócitos B/imunologia , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/imunologia , Transtornos Linfoproliferativos/virologia , NF-kappa B/imunologia , Linfócitos B/patologia , Proteínas Adaptadoras de Sinalização CARD/genética , Proliferação de Células , Anergia Clonal , Guanilato Ciclase/genética , Herpesvirus Humano 4 , Humanos , Ativação Linfocitária , Transtornos Linfoproliferativos/genética , Transtornos Linfoproliferativos/fisiopatologia , Mutação , Transdução de Sinais/imunologia , Transdução de Sinais/fisiologia , Linfócitos T/imunologia , Viremia
14.
Ann Rheum Dis ; 77(4): 612-619, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29358286

RESUMO

OBJECTIVES: To characterise the clinical features, immune manifestations and molecular mechanisms in a recently described autoinflammatory disease caused by mutations in TRNT1, a tRNA processing enzyme, and to explore the use of cytokine inhibitors in suppressing the inflammatory phenotype. METHODS: We studied nine patients with biallelic mutations in TRNT1 and the syndrome of congenital sideroblastic anaemia with immunodeficiency, fevers and developmental delay (SIFD). Genetic studies included whole exome sequencing (WES) and candidate gene screening. Patients' primary cells were used for deep RNA and tRNA sequencing, cytokine profiling, immunophenotyping, immunoblotting and electron microscopy (EM). RESULTS: We identified eight mutations in these nine patients, three of which have not been previously associated with SIFD. Three patients died in early childhood. Inflammatory cytokines, mainly interleukin (IL)-6, interferon gamma (IFN-γ) and IFN-induced cytokines were elevated in the serum, whereas tumour necrosis factor (TNF) and IL-1ß were present in tissue biopsies of patients with active inflammatory disease. Deep tRNA sequencing of patients' fibroblasts showed significant deficiency of mature cytosolic tRNAs. EM of bone marrow and skin biopsy samples revealed striking abnormalities across all cell types and a mix of necrotic and normal-appearing cells. By immunoprecipitation, we found evidence for dysregulation in protein clearance pathways. In 4/4 patients, treatment with a TNF inhibitor suppressed inflammation, reduced the need for blood transfusions and improved growth. CONCLUSIONS: Mutations of TRNT1 lead to a severe and often fatal syndrome, linking protein homeostasis and autoinflammation. Molecular diagnosis in early life will be crucial for initiating anti-TNF therapy, which might prevent some of the severe disease consequences.


Assuntos
Anemia Sideroblástica/genética , Anti-Inflamatórios/uso terapêutico , Doenças Genéticas Ligadas ao Cromossomo X/genética , Síndromes de Imunodeficiência/genética , Mutação , Nucleotidiltransferases/genética , RNA de Transferência/genética , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Adulto , Anemia Sideroblástica/sangue , Criança , Pré-Escolar , Citocinas/sangue , Citocinas/genética , Deficiências do Desenvolvimento/genética , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/sangue , Humanos , Imunofenotipagem , Masculino , Linhagem , Fenótipo , Fator de Necrose Tumoral alfa/análise , Sequenciamento Completo do Exoma
16.
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
17.
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
18.
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
19.
J Infect Dis ; 216(1): 14-21, 2017 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-28531322

RESUMO

Background: Interferon-induced transmembrane protein 3 (IFITM3) restricts endocytic fusion of influenza virus. IFITM3 rs12252_C, a putative alternate splice site, has been associated with influenza severity in adults. IFITM3 has not been evaluated in pediatric influenza. Methods: The Pediatric Influenza (PICFLU) study enrolled children with suspected influenza infection across 38 pediatric intensive care units during November 2008 to April 2016. IFITM3 was sequenced in patients and parents were genotyped for specific variants for family-based association testing. rs12252 was genotyped in 54 African-American pediatric outpatients with influenza (FLU09), included in the population-based comparisons with 1000 genomes. Splice site analysis of rs12252_C was performed using PICFLU and FLU09 patient RNA. Results: In PICFLU, 358 children had influenza infection. We identified 22 rs12252_C homozygotes in 185 white non-Hispanic children. rs12252_C was not associated with influenza infection in population or family-based analyses. We did not identify the Δ21 IFITM3 isoform in RNAseq data. The rs12252 genotype was not associated with IFITM3 expression levels, nor with critical illness severity. No novel rare IFITM3 functional variants were identified. Conclusions: rs12252 was not associated with susceptibility to influenza-related critical illness in children or with critical illness severity. Our data also do not support it being a splice site.


Assuntos
Influenza Humana/genética , Proteínas de Membrana/genética , Proteínas de Ligação a RNA/genética , Afro-Americanos/genética , Criança , Pré-Escolar , Feminino , Predisposição Genética para Doença , Técnicas de Genotipagem , Homozigoto , Humanos , Vírus da Influenza A , Masculino , Polimorfismo de Nucleotídeo Único , Estudos Prospectivos , Isoformas de Proteínas/genética , RNA Viral/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA