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1.
Proc Natl Acad Sci U S A ; 117(46): 29155-29165, 2020 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-33139539

RESUMO

LRRC8 family proteins on the plasma membrane play a critical role in cellular osmoregulation by forming volume-regulated anion channels (VRACs) necessary to prevent necrotic cell death. We demonstrate that intracellular LRRC8 proteins acting within lysosomes also play an essential role in cellular osmoregulation. LRRC8 proteins on lysosome membranes generate large lysosomal volume-regulated anion channel (Lyso-VRAC) currents in response to low cytoplasmic ionic strength conditions. When a double-leucine L706L707 motif at the C terminus of LRRC8A was mutated to alanines, normal plasma membrane VRAC currents were still observed, but Lyso-VRAC currents were absent. We used this targeting mutant, as well as pharmacological tools, to demonstrate that Lyso-VRAC currents are necessary for the formation of large lysosome-derived vacuoles, which store and then expel excess water to maintain cytosolic water homeostasis. Thus, Lyso-VRACs allow lysosomes of mammalian cells to act as the cell`s "bladder." When Lyso-VRAC current was selectively eliminated, the extent of necrotic cell death to sustained stress was greatly increased, not only in response to hypoosmotic stress, but also to hypoxic and hypothermic stresses. Thus Lyso-VRACs play an essential role in enabling cells to mount successful homeostatic responses to multiple stressors.

2.
Artigo em Inglês | MEDLINE | ID: mdl-33096268

RESUMO

BACKGROUND: Iron uptake mediated by transferrin receptor 1 (TfR1), encoded by the TFRC gene, is essential for lymphocyte development and proliferation. Autosomal-recessive mutations in the human TFRC gene cause a combined immunodeficiency characterized by defective T- and B-cell proliferation as well as impaired class-switching. Clinical presentations have been severe in all reported cases, with symptoms including recurrent sinopulmonary infections, hypogammaglobulinemia, chronic diarrhea, and intermittent cytopenias. OBJECTIVE: To describe outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) in patients with TFRC deficiency. METHODS: Retrospective chart review study of 5 patients with TFRC deficiency who underwent allogeneic HSCT between July 2011 and May 2018 at Boston Children's Hospital. RESULTS: Intermittent thrombocytopenia and neutropenia were a predominant feature of the clinical presentation in our cohort, and 3 patients who underwent bone marrow evaluation before HSCT were found to have signs of dysmyelopoiesis and dysplasia. One patient, who had a transplant at age 11 years, developed a clonal cytogenetic abnormality concerning for myelodysplastic syndrome. All 5 patients tolerated myeloablative conditioning regimens and had robust donor cell engraftment with resolution of cytopenias and independence from intravenous immunoglobulin substitution. All 5 patients were alive at a median follow-up of 47.1 months posttransplant (range, 15.7-85.4) and none had developed acute or chronic graft-versus-host disease. CONCLUSIONS: Allogeneic HSCT is curative for TFRC deficiency and rescues all known disease manifestations. Patients with TFRC deficiency may have a predisposition to malignant transformation of hematopoietic cells and may benefit from HSCT earlier in their disease course.

3.
Commun Biol ; 3(1): 621, 2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33110194

RESUMO

Iron is essential for living cells. Uptake of iron-loaded transferrin by the transferrin receptor 1 (CD71, TFR) is a major but not sufficient mechanism and an alternative iron-loaded ligand for CD71 has been assumed. Here, we demonstrate that CD71 utilizes heme-albumin as cargo to transport iron into human cells. Binding and endocytosis of heme-albumin via CD71 was sufficient to promote proliferation of various cell types in the absence of transferrin. Growth and differentiation of cells induced by heme-albumin was dependent on heme-oxygenase 1 (HO-1) function and was accompanied with an increase of the intracellular labile iron pool (LIP). Import of heme-albumin via CD71 was further found to contribute to the efficacy of albumin-based drugs such as the chemotherapeutic Abraxane. Thus, heme-albumin/CD71 interaction is a novel route to transport nutrients or drugs into cells and adds to the emerging function of CD71 as a scavenger receptor.

4.
Artigo em Inglês | MEDLINE | ID: mdl-32888943

RESUMO

BACKGROUND: Next-generation sequencing has become a first-line tool for the diagnosis of primary immunodeficiency. However, patient access remains limited because of restricted insurance coverage and a lack of guidelines addressing the use of targeted panels versus whole-exome sequencing (WES). OBJECTIVES: We sought to compare targeted next-generation sequencing with WES in a global population of patients with primary immunodeficiency. METHODS: This was a longitudinal study of 878 patients with likely primary immunodeficiency sequenced between 2010 and 2020. Most patients (n = 780) were first sequenced using a 264 gene panel. This was followed by WES in selected cases if a candidate gene was not found. A subset of patients (n = 98) were selected for a WES-only pipeline if the history was atypical for genes within the targeted panel. RESULTS: Disease-causing variants were identified in 498 of the 878 probands (56%), encompassing 152 distinct monogenic disorders. Sixteen patients had disorders that were novel at the time of sequencing (1.8%). Diagnostic yield in patients sequenced by targeted panel was 56% (433 of 780 patients), with subsequent WES leading to an additional 18 diagnoses (overall diagnostic yield 58%, 451 of 780 patients). The WES-only approach had a diagnostic yield of 45% (45 of 98 patients), reflecting that these cases had less common clinical and laboratory phenotypes. Cost analysis, based on current commercial WES and targeted panel prices, demonstrated savings ranging from $300 to $950 with a WES-only approach, depending on diagnostic yield. CONCLUSIONS: Advantages of WES over targeted next-generation sequencing include simplified workflow, reduced overall cost, and the potential for identification of novel diseases.

5.
J Allergy Clin Immunol ; 146(5): 1194-1200.e1, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32853638

RESUMO

BACKGROUND: We studied 2 unrelated patients with immune thrombocytopenia and autoimmune hemolytic anemia in the setting of acute infections. One patient developed multisystem inflammatory syndrome in children in the setting of a severe acute respiratory syndrome coronavirus 2 infection. OBJECTIVES: We sought to identify the mechanisms underlying the development of infection-driven autoimmune cytopenias. METHODS: Whole-exome sequencing was performed on both patients, and the impact of the identified variants was validated by functional assays using the patients' PBMCs. RESULTS: Each patient was found to have a unique heterozygous truncation variant in suppressor of cytokine signaling 1 (SOCS1). SOCS1 is an essential negative regulator of type I and type II IFN signaling. The patients' PBMCs showed increased levels of signal transducer and activator of transcription 1 phosphorylation and a transcriptional signature characterized by increased expression of type I and type II IFN-stimulated genes and proapoptotic genes. The enhanced IFN signature exhibited by the patients' unstimulated PBMCs parallels the hyperinflammatory state associated with multisystem inflammatory syndrome in children, suggesting the contributions of SOCS1 in regulating the inflammatory response characteristic of multisystem inflammatory syndrome in children. CONCLUSIONS: Heterozygous loss-of-function SOCS1 mutations are associated with enhanced IFN signaling and increased immune cell activation, thereby predisposing to infection-associated autoimmune cytopenias.


Assuntos
Anemia Hemolítica Autoimune/imunologia , Anemia Hemolítica Autoimune/virologia , Infecções por Coronavirus/complicações , Pneumonia Viral/complicações , Síndrome de Resposta Inflamatória Sistêmica/imunologia , Síndrome de Resposta Inflamatória Sistêmica/virologia , Trombocitopenia/imunologia , Trombocitopenia/virologia , Adolescente , Anemia Hemolítica Autoimune/genética , Betacoronavirus , Pré-Escolar , Infecções por Coronavirus/imunologia , Haploinsuficiência , Humanos , Masculino , Mutação , Pandemias , Pneumonia Viral/imunologia , Proteína 1 Supressora da Sinalização de Citocina/genética , Trombocitopenia/genética
7.
J Allergy Clin Immunol Pract ; 8(10): 3543-3548, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32707237

RESUMO

BACKGROUND: Chronic granulomatous disease is a primary immunodeficiency characterized by recurrent bacterial and fungal infections, granuloma formation, and inflammatory disease. Impaired neutrophil oxidative function is an essential diagnostic criterion. In vitro exposure of neutrophils to acetaminophen, a commonly used over-the-counter medication, has been associated with reduced neutrophil oxidative function. The clinical implications of acetaminophen intake for dihydrorhodamine (DHR) testing remain unknown. OBJECTIVE: To evaluate the effect of in vivo administration of therapeutic doses of acetaminophen on DHR diagnostic testing. METHODS: We performed DHR testing in 15 healthy adults before and after administering a single dose of acetaminophen. We retrospectively reviewed 195 DHR test results from hospitalized patients who had received acetaminophen, nonsteroidal anti-inflammatory drug, or corticosteroid before testing. RESULTS: DHR testing result was abnormal in 100% (n = 15) of healthy adults 2 hours after acetaminophen intake. We identified 195 instances of DHR testing less than or equal to 72 hours after acetaminophen ingestion in hospitalized patients who did not have chronic granulomatous disease. DHR results were abnormal in 43 of 195 cases (22.1%). Frequency of false-positive testing was increased in patients who received acetaminophen within 24 hours of testing, and in patients who received more than 1 dose of acetaminophen. Nonsteroidal anti-inflammatory drug and corticosteroid intakes were not associated with abnormal DHR result. CONCLUSIONS: Patients treated with acetaminophen have decreased neutrophil oxidative burst as measured by DHR testing. To avoid falsely abnormal testing for chronic granulomatous disease, patients should be advised to avoid acetaminophen for at least 24 hours before DHR testing.

8.
J Clin Invest ; 130(11): 5942-5950, 2020 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-32701511

RESUMO

BACKGROUNDPediatric SARS-CoV-2 infection can be complicated by a dangerous hyperinflammatory condition termed multisystem inflammatory syndrome in children (MIS-C). The clinical and immunologic spectrum of MIS-C and its relationship to other inflammatory conditions of childhood have not been studied in detail.METHODSWe retrospectively studied confirmed cases of MIS-C at our institution from March to June 2020. The clinical characteristics, laboratory studies, and treatment response were collected. Data were compared with historic cohorts of Kawasaki disease (KD) and macrophage activation syndrome (MAS).RESULTSTwenty-eight patients fulfilled the case definition of MIS-C. Median age at presentation was 9 years (range: 1 month to 17 years); 50% of patients had preexisting conditions. All patients had laboratory confirmation of SARS-CoV-2 infection. Seventeen patients (61%) required intensive care, including 7 patients (25%) who required inotrope support. Seven patients (25%) met criteria for complete or incomplete KD, and coronary abnormalities were found in 6 cases. Lymphopenia, thrombocytopenia, and elevation in inflammatory markers, D-dimer, B-type natriuretic peptide, IL-6, and IL-10 levels were common but not ubiquitous. Cytopenias distinguished MIS-C from KD and the degree of hyperferritinemia and pattern of cytokine production differed between MIS-C and MAS. Immunomodulatory therapy given to patients with MIS-C included intravenous immune globulin (IVIG) (71%), corticosteroids (61%), and anakinra (18%). Clinical and laboratory improvement were observed in all cases, including 6 cases that did not require immunomodulatory therapy. No mortality was recorded in this cohort.CONCLUSIONMIS-C encompasses a broad phenotypic spectrum with clinical and laboratory features distinct from KD and MAS.FUNDINGThis work was supported by the National Institutes of Health, National Institute of Arthritis and Musculoskeletal and Skin Diseases; the National Institute of Allergy and Infectious Diseases; Rheumatology Research Foundation Investigator Awards and Medical Education Award; Boston Children's Hospital Faculty Career Development Awards; the McCance Family Foundation; and the Samara Jan Turkel Center.


Assuntos
Corticosteroides/administração & dosagem , Betacoronavirus/metabolismo , Imunoglobulinas Intravenosas/administração & dosagem , Imunomodulação , Proteína Antagonista do Receptor de Interleucina 1/administração & dosagem , Síndrome de Resposta Inflamatória Sistêmica , Adolescente , Biomarcadores/sangue , Criança , Pré-Escolar , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Humanos , Lactente , Interleucina-10/sangue , Interleucina-6/sangue , Síndrome de Ativação Macrofágica/sangue , Síndrome de Ativação Macrofágica/diagnóstico , Síndrome de Ativação Macrofágica/tratamento farmacológico , Síndrome de Ativação Macrofágica/imunologia , Masculino , Síndrome de Linfonodos Mucocutâneos/sangue , Síndrome de Linfonodos Mucocutâneos/diagnóstico , Síndrome de Linfonodos Mucocutâneos/tratamento farmacológico , Síndrome de Linfonodos Mucocutâneos/imunologia , Peptídeo Natriurético Encefálico/sangue , Estudos Retrospectivos , Síndrome de Resposta Inflamatória Sistêmica/sangue , Síndrome de Resposta Inflamatória Sistêmica/diagnóstico , Síndrome de Resposta Inflamatória Sistêmica/tratamento farmacológico , Síndrome de Resposta Inflamatória Sistêmica/imunologia
10.
Clin Immunol ; 216: 108459, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32418917

RESUMO

The COVID-19 pandemic is one of the greatest infectious challenges in recent history. Presently, few treatment options exist and the availability of effective vaccines is at least one year away. There is an urgent need to find currently available, effective therapies in the treatment of patients with COVID-19 infection. In this review, we compare and contrast the use of intravenous immunoglobulin and hyperimmune globulin in the treatment of COVID-19 infection.


Assuntos
Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Síndrome da Liberação de Citocina/patologia , Imunoglobulinas Intravenosas/administração & dosagem , Fatores Imunológicos/administração & dosagem , Pandemias , Pneumonia Viral/tratamento farmacológico , Imunidade Adaptativa/efeitos dos fármacos , Anticorpos Facilitadores/efeitos dos fármacos , Betacoronavirus/imunologia , Betacoronavirus/patogenicidade , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/terapia , Infecções por Coronavirus/virologia , Síndrome da Liberação de Citocina/etiologia , Síndrome da Liberação de Citocina/imunologia , Síndrome da Liberação de Citocina/prevenção & controle , Expressão Gênica , Humanos , Imunidade Inata/efeitos dos fármacos , Imunização Passiva/efeitos adversos , Imunização Passiva/métodos , Imunoglobulinas Intravenosas/efeitos adversos , Fatores Imunológicos/efeitos adversos , Terapia de Alvo Molecular , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/imunologia , Pneumonia Viral/epidemiologia , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/virologia
11.
J Allergy Clin Immunol ; 146(4): 901-911, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32278790

RESUMO

BACKGROUND: An increasing number of NFKB1 variants are being identified in patients with heterogeneous immunologic phenotypes. OBJECTIVE: To characterize the clinical and cellular phenotype as well as the management of patients with heterozygous NFKB1 mutations. METHODS: In a worldwide collaborative effort, we evaluated 231 individuals harboring 105 distinct heterozygous NFKB1 variants. To provide evidence for pathogenicity, each variant was assessed in silico; in addition, 32 variants were assessed by functional in vitro testing of nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB) signaling. RESULTS: We classified 56 of the 105 distinct NFKB1 variants in 157 individuals from 68 unrelated families as pathogenic. Incomplete clinical penetrance (70%) and age-dependent severity of NFKB1-related phenotypes were observed. The phenotype included hypogammaglobulinemia (88.9%), reduced switched memory B cells (60.3%), and respiratory (83%) and gastrointestinal (28.6%) infections, thus characterizing the disorder as primary immunodeficiency. However, the high frequency of autoimmunity (57.4%), lymphoproliferation (52.4%), noninfectious enteropathy (23.1%), opportunistic infections (15.7%), autoinflammation (29.6%), and malignancy (16.8%) identified NF-κB1-related disease as an inborn error of immunity with immune dysregulation, rather than a mere primary immunodeficiency. Current treatment includes immunoglobulin replacement and immunosuppressive agents. CONCLUSIONS: We present a comprehensive clinical overview of the NF-κB1-related phenotype, which includes immunodeficiency, autoimmunity, autoinflammation, and cancer. Because of its multisystem involvement, clinicians from each and every medical discipline need to be made aware of this autosomal-dominant disease. Hematopoietic stem cell transplantation and NF-κB1 pathway-targeted therapeutic strategies should be considered in the future.

13.
J Allergy Clin Immunol ; 145(6): 1664-1672.e10, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31945408

RESUMO

BACKGROUND: Deficiency of adenosine deaminase 2 (DADA2) is a syndrome with pleiotropic manifestations including vasculitis and hematologic compromise. A systematic definition of the relationship between adenosine deaminase 2 (ADA2) mutations and clinical phenotype remains unavailable. OBJECTIVE: We sought to test whether the impact of ADA2 mutations on enzyme function correlates with clinical presentation. METHODS: Patients with DADA2 with severe hematologic manifestations were compared with vasculitis-predominant patients. Enzymatic activity was assessed using expression constructs reflecting all 53 missense, nonsense, insertion, and deletion genotypes from 152 patients across the DADA2 spectrum. RESULTS: We identified patients with DADA2 presenting with pure red cell aplasia (n = 5) or bone marrow failure (BMF, n = 10) syndrome. Most patients did not exhibit features of vasculitis. Recurrent infection, hepatosplenomegaly, and gingivitis were common in patients with BMF, of whom half died from infection. Unlike patients with DADA2 with vasculitis, patients with pure red cell aplasia and BMF proved largely refractory to TNF inhibitors. ADA2 variants associated with vasculitis predominantly reflected missense mutations with at least 3% residual enzymatic activity. In contrast, pure red cell aplasia and BMF were associated with missense mutations with minimal residual enzyme activity, nonsense variants, and insertions/deletions resulting in complete loss of function. CONCLUSIONS: Functional interrogation of ADA2 mutations reveals an association of subtotal function loss with vasculitis, typically responsive to TNF blockade, whereas more extensive loss is observed in hematologic disease, which may be refractory to treatment. These findings establish a genotype-phenotype spectrum in DADA2.

14.
Curr Opin Rheumatol ; 32(2): 168-174, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31977526

RESUMO

PURPOSE OF REVIEW: Advances in genomics and animal models of human disease have enabled the discovery of mechanisms important for host immunity and self-tolerance. Here, we summarize conceptual and clinical discoveries identified from 2018 to 2019 in the field of primary immunodeficiencies and autoimmunity. RECENT FINDINGS: Three new primary immunodeficiencies with autoimmunity were identified and the clinical phenotypes of NFKB1 haploinsufficiency and RASGRP1 deficiency were expanded. A diversity of novel mechanisms leading to autoimmunity associated with primary immunodeficiencies (PIDs) was reported, including pathways important for the metabolism and function of regulatory T cells and germinal B cells, the contribution of neutrophil extracellular traps to plasmacytoid dendritic cell activation and the influence of commensal bacteria on the generation of autoantibodies. With regard to therapeutic developments in the field, we highlight the use of janus kinase inhibitors for immune dysregulation associated with gain-of-function variants in STAT1 and STAT3, as well as the risks of persistent hypogammaglobulinemia associated with rituximab treatment. SUMMARY: Mechanistic studies of PIDs with autoimmunity elucidate key principles governing the balance between immune surveillance and self-tolerance.


Assuntos
Autoimunidade/imunologia , Síndromes de Imunodeficiência/imunologia , Linfócitos T Reguladores/imunologia , Animais , Autoanticorpos/imunologia , Humanos , Tolerância Imunológica
15.
J Allergy Clin Immunol ; 146(1): 192-202, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31862378

RESUMO

BACKGROUND: The gene AK2 encodes the phosphotransferase adenylate kinase 2 (AK2). Human variants in AK2 cause reticular dysgenesis, a severe combined immunodeficiency with agranulocytosis, lymphopenia, and sensorineural deafness that requires hematopoietic stem cell transplantation for survival. OBJECTIVE: We investigated the mechanisms underlying recurrent sinopulmonary infections and hypogammaglobulinemia in 15 patients, ranging from 3 to 34 years of age, from 9 kindreds. Only 2 patients, both of whom had mildly impaired T-cell proliferation, each had a single clinically significant opportunistic infection. METHODS: Patient cells were studied with next-generation DNA sequencing, tandem mass spectrometry, and assays of lymphocyte and mitochondrial function. RESULTS: We identified 2 different homozygous variants in AK2. AK2G100S and AK2A182D permit residual protein expression, enzymatic activity, and normal numbers of neutrophils and lymphocytes. All but 1 patient had intact hearing. The patients' B cells had severely impaired proliferation and in vitro immunoglobulin secretion. With activation, the patients' B cells exhibited defective mitochondrial respiration and impaired regulation of mitochondrial membrane potential and quality. Although activated T cells from the patients with opportunistic infections demonstrated impaired mitochondrial function, the mitochondrial quality in T cells was preserved. Consistent with the capacity of activated T cells to utilize nonmitochondrial metabolism, these findings revealed a less strict cellular dependence of T-cell function on AK2 activity. Chemical inhibition of ATP synthesis in control T and B cells similarly demonstrated the greater dependency of B cells on mitochondrial function. CONCLUSIONS: Our patients demonstrate the in vivo sequelae of the cell-specific requirements for the functions of AK2 and mitochondria, particularly in B-cell activation and antibody production.

16.
J Allergy Clin Immunol ; 145(1): 46-69, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31568798

RESUMO

Genetic testing has become an integral component of the diagnostic evaluation of patients with suspected primary immunodeficiency diseases. Results of genetic testing can have a profound effect on clinical management decisions. Therefore clinical providers must demonstrate proficiency in interpreting genetic data. Because of the need for increased knowledge regarding this practice, the American Academy of Allergy, Asthma & Immunology Primary Immunodeficiency Diseases Committee established a work group that reviewed and summarized information concerning appropriate methods, tools, and resources for evaluating variants identified by genetic testing. Strengths and limitations of tests frequently ordered by clinicians were examined. Summary statements and tables were then developed to guide the interpretation process. Finally, the need for research and collaboration was emphasized. Greater understanding of these important concepts will improve the diagnosis and management of patients with suspected primary immunodeficiency diseases.


Assuntos
Testes Genéticos , Doenças da Imunodeficiência Primária , Asma , Humanos , Doenças da Imunodeficiência Primária/diagnóstico , Doenças da Imunodeficiência Primária/genética , Doenças da Imunodeficiência Primária/terapia , Estados Unidos
17.
Clin Immunol ; 210: 108311, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31760094

RESUMO

Activated PI3Kδ syndrome (APDS) Type I results from gain-of-function mutations in PIK3CD, which encodes the p110δ subunit of PI3Kδ. Abnormal actin dynamics have been hypothesized to contribute to the lymphopenia associated with this disease but have not been studied in patients with APDS. We report a patient with APDS who had widespread necrotic skin lesions that were responsive specifically to immunosuppressive therapy. EBV-transformed lymphoblastoid cells (EBV-LCLs) from patients with APDS exhibit increased polymerized actin and increased apoptosis, suggesting a contribution of impaired actin dynamics to this disease.


Assuntos
Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Pele/patologia , Citoesqueleto de Actina/genética , Apoptose , Células Cultivadas , Pré-Escolar , Classe I de Fosfatidilinositol 3-Quinases/genética , Feminino , Mutação com Ganho de Função/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Linfopenia , Necrose , Doenças da Imunodeficiência Primária/genética
18.
Clin Immunol ; 207: 40-42, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31301515

RESUMO

Mutations in MYD88 cause susceptibility to invasive bacterial infections through impaired signaling downstream of toll-like receptors (TLRs) and IL-1 receptors. We studied a patient presenting with neutropenia, delayed umbilical cord separation, BCG adenitis, andP. aeruginosapneumonia. Next-generation DNA sequencing identified a novel homozygous truncation mutation in MYD88 that abolishes MyD88 expression. The patient's dermal fibroblasts had severely impaired IL-6 production after stimulation with ligands for the MyD88-dependent receptors TLR2, TLR4 and IL-1R, while responses to ligands for the MyD88-independent receptors TLR3 and TNF-α were preserved. Notably, secretion of TNF-α, which is essential for BCG control, was also impaired after LPS stimulation. In this first report of BCG infection in MyD88 deficiency, data suggest that MyD88-dependent TNF-α production contributes to control of mycobacterial disease.


Assuntos
Vacina BCG/efeitos adversos , Linfadenite/patologia , Fator 88 de Diferenciação Mieloide/genética , Neutropenia/genética , Pneumonia Bacteriana/microbiologia , Cordão Umbilical/patologia , Vacina BCG/imunologia , Predisposição Genética para Doença , Humanos , Masculino , Neutropenia/patologia , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa
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