RESUMO
Studies of the monogenic autoimmune disease immunodysregulation polyendocrinopathy enteropathy X-linked syndrome (IPEX) have elucidated the essential function of the transcription factor FOXP3 and thymic-derived regulatory T cells (Tregs) in controlling peripheral tolerance. However, the presence and the source of autoreactive T cells in IPEX remain undetermined. Here, we investigated how FOXP3 deficiency affects the T cell receptor (TCR) repertoire and Treg stability in vivo and compared T cell abnormalities in patients with IPEX with those in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED). To study Tregs independently of their phenotype and to analyze T cell autoreactivity, we combined Treg-specific demethylation region analyses, single-cell multiomic profiling, and bulk TCR sequencing. We found that patients with IPEX, unlike patients with APECED, have expanded autoreactive T cells originating from both autoreactive effector T cells (Teffs) and Tregs. In addition, a fraction of the expanded Tregs from patients with IPEX lost their phenotypic and functional markers, including CD25 and FOXP3. Functional experiments with CRISPR-Cas9-mediated FOXP3 knockout Tregs and Tregs from patients with IPEX indicated that the patients' Tregs gain a TH2-skewed Teff-like function, which is consistent with immune dysregulation observed in these patients. Analyses of FOXP3 mutation-carrier mothers and a patient with IPEX after hematopoietic stem cell transplantation indicated that Tregs expressing nonmutated FOXP3 prevent the accumulation of autoreactive Teffs and unstable Tregs. These findings could be directly used for diagnostic and prognostic purposes and for monitoring the effects of immunomodulatory treatments.
Assuntos
Doenças Genéticas Ligadas ao Cromossomo X , Poliendocrinopatias Autoimunes , Humanos , Poliendocrinopatias Autoimunes/genética , Poliendocrinopatias Autoimunes/terapia , Doenças Genéticas Ligadas ao Cromossomo X/genética , Linfócitos T Reguladores , Mutação/genética , Síndrome , Fatores de Transcrição Forkhead/genética , Receptores de Antígenos de Linfócitos T/genéticaRESUMO
X-Linked Hyper-IgM Syndrome is caused by pathogenic variants in CD40LG. Three patients with atypical clinical and immunological features were identified with variants in CD40LG requiring further characterization. Flow cytometry was used to evaluate CD40L protein expression and binding capacity to a surrogate receptor, CD40-muIg. Though functional anomalies were observed, there was still a lack of clarity regarding the underlying mechanism. We developed structural models for wild-type and the three variants of CD40L protein observed in these patients (p. Lys143Asn, Leu225Ser and Met36Arg) to evaluate structural alterations by molecular mechanic calculations, and assess protein movement by molecular dynamic simulations. These studies demonstrate that functional analysis of variants of unknown significance in CD40LG can be supplemented by advanced computational analysis in atypical clinical contexts. These studies in combination identify the deleterious effects of these variants and potential mechanisms for protein dysfunction.
Assuntos
Ligante de CD40 , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1 , Síndrome de Imunodeficiência com Hiper-IgM , Humanos , Antígenos CD40 , Ligante de CD40/genética , Síndrome de Imunodeficiência com Hiper-IgM Tipo 1/genética , Imunoglobulina M , MutaçãoAssuntos
Doença Granulomatosa Crônica , Histoplasmose , Hipertensão Pulmonar , Humanos , Criança , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , Doença Granulomatosa Crônica/complicações , Doença Granulomatosa Crônica/diagnóstico , Doença Granulomatosa Crônica/tratamento farmacológico , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/tratamento farmacológico , Hipertensão Pulmonar/etiologia , HistoplasmaAssuntos
Doença Granulomatosa Crônica , Lipoblastoma , Neoplasias do Mediastino , NADPH Oxidase 2/genética , Pneumonia , Criança , Doença Granulomatosa Crônica/diagnóstico por imagem , Doença Granulomatosa Crônica/genética , Doença Granulomatosa Crônica/patologia , Humanos , Lipoblastoma/diagnóstico por imagem , Lipoblastoma/genética , Lipoblastoma/patologia , Pulmão/diagnóstico por imagem , Pulmão/patologia , Masculino , Neoplasias do Mediastino/diagnóstico por imagem , Neoplasias do Mediastino/genética , Neoplasias do Mediastino/patologia , Pneumonia/diagnóstico por imagem , Pneumonia/genética , Pneumonia/patologiaRESUMO
Chronic granulomatous disease (CGD) is an immunodeficiency disorder affecting about 1 in 250,000 individuals. CGD patients suffer from severe bacterial and fungal infections. The disease is caused by a lack of superoxide production by the leukocyte enzyme NADPH oxidase. Superoxide and subsequently formed other reactive oxygen species (ROS) are instrumental in killing phagocytosed micro-organisms in neutrophils, eosinophils, monocytes and macrophages. The leukocyte NADPH oxidase is composed of five subunits, of which the enzymatic component is gp91phox, also called Nox2. This protein is encoded by the CYBB gene on the X chromosome. Mutations in this gene are found in about 70% of all CGD patients in Europe and in about 20% in countries with a high ratio of parental consanguinity. This article lists all mutations identified in CYBB and should therefore help in genetic counseling of X-CGD patients' families. Moreover, apparently benign polymorphisms in CYBB are also given, which should facilitate the recognition of disease-causing mutations. In addition, we also include some mutations in G6PD, the gene on the X chromosome that encodes glucose-6-phosphate dehydrogenase, because inactivity of this enzyme may lead to shortage of NADPH and thus to insufficient activity of NADPH oxidase. Severe G6PD deficiency can induce CGD-like symptoms.
Assuntos
Cromossomos Humanos X/genética , Doença Granulomatosa Crônica/genética , Mutação , NADPH Oxidase 2/genética , HumanosRESUMO
Constrictive pericarditis is the final common result of a number of processes that affect the pericardium. Establishing the diagnosis and determining the underlying etiology of constrictive pericarditis are often a diagnostic rendezvous. Here, we describe a patient who presented to the general practitioner with edema, ascites, and weight gain and was found to have constrictive pericarditis secondary to an inflammatory myofibroblastic tumor of the mediastinum. Interestingly, she had a relative lack of cardiorespiratory complaints, and, aside from the edema and mildly elevated jugular venous pressure, she had an unremarkable cardiac and pulmonary examination. During the diagnostic evaluation for constrictive pericarditis, she was found to have hypogammaglobulinemia and profound lymphocytopenia. A stool α-1-antitrypsin level was sent and was elevated, which confirmed the diagnosis of protein-losing enteropathy, a rare but important complication of constrictive pericarditis. This case highlights important diagnostic considerations and management of these complications for the general practitioner.
Assuntos
Agamaglobulinemia/complicações , Pericardite Constritiva/complicações , Adolescente , Feminino , Humanos , Pericardite Constritiva/diagnóstico por imagemRESUMO
Inborn errors of immunity (IEI) are a genetically heterogeneous group of disorders with a broad clinical spectrum. Identification of molecular and functional bases of these disorders is important for diagnosis, treatment, and an understanding of the human immune response. We identified 6 unrelated males with neutropenia, infections, lymphoproliferation, humoral immune defects, and in some cases bone marrow failure associated with 3 different variants in the X-linked gene TLR8, encoding the endosomal Toll-like receptor 8 (TLR8). Interestingly, 5 patients had somatic variants in TLR8 with <30% mosaicism, suggesting a dominant mechanism responsible for the clinical phenotype. Mosaicism was also detected in skin-derived fibroblasts in 3 patients, demonstrating that mutations were not limited to the hematopoietic compartment. All patients had refractory chronic neutropenia, and 3 patients underwent allogeneic hematopoietic cell transplantation. All variants conferred gain of function to TLR8 protein, and immune phenotyping demonstrated a proinflammatory phenotype with activated T cells and elevated serum cytokines associated with impaired B-cell maturation. Differentiation of myeloid cells from patient-derived induced pluripotent stem cells demonstrated increased responsiveness to TLR8. Together, these findings demonstrate that gain-of-function variants in TLR8 lead to a novel childhood-onset IEI with lymphoproliferation, neutropenia, infectious susceptibility, B- and T-cell defects, and in some cases, bone marrow failure. Somatic mosaicism is a prominent molecular mechanism of this new disease.
Assuntos
Transtornos da Insuficiência da Medula Óssea/patologia , Mutação com Ganho de Função , Síndromes de Imunodeficiência/patologia , Inflamação/patologia , Mosaicismo , Pancitopenia/patologia , Receptor 8 Toll-Like/genética , Adolescente , Adulto , Linfócitos B/patologia , Transtornos da Insuficiência da Medula Óssea/etiologia , Transtornos da Insuficiência da Medula Óssea/metabolismo , Diferenciação Celular , Criança , Pré-Escolar , Citocinas/metabolismo , Feminino , Seguimentos , Humanos , Síndromes de Imunodeficiência/etiologia , Síndromes de Imunodeficiência/metabolismo , Lactente , Inflamação/etiologia , Inflamação/metabolismo , Ativação Linfocitária , Masculino , Pancitopenia/etiologia , Pancitopenia/metabolismo , Linhagem , Prognóstico , Linfócitos T/imunologia , Adulto JovemAssuntos
Empiema/diagnóstico , Predisposição Genética para Doença , Doença Granulomatosa Crônica/diagnóstico , Doença Granulomatosa Crônica/genética , Mutação , NADPH Oxidase 2/genética , Biomarcadores , Pré-Escolar , Empiema/complicações , Ativação Enzimática , Estudos de Associação Genética , Doença Granulomatosa Crônica/complicações , Doença Granulomatosa Crônica/terapia , Humanos , Masculino , NADPH Oxidases/genética , NADPH Oxidases/metabolismo , Avaliação de Sintomas , Tomografia Computadorizada por Raios XAssuntos
COVID-19/diagnóstico , Doença Granulomatosa Crônica/imunologia , Linfopenia/imunologia , SARS-CoV-2/imunologia , Linfócitos T/imunologia , Infecções Assintomáticas , COVID-19/imunologia , COVID-19/virologia , Doença Granulomatosa Crônica/complicações , Doença Granulomatosa Crônica/terapia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Lactente , Linfopenia/complicações , Linfopenia/terapia , Masculino , SARS-CoV-2/isolamento & purificaçãoRESUMO
BACKGROUND: Infants with severe respiratory syncytial virus (RSV) bronchiolitis have an increased risk of recurrent wheezing and asthma. We aimed to evaluate the relationships between regulatory T cell (Treg) percentage and cytokine production of in vitro-stimulated CD4+ T cells during acute bronchiolitis and the development of recurrent wheezing in the first 3 years of life. METHODS: We obtained peripheral blood from 166 infants hospitalized with their first episode of RSV-confirmed bronchiolitis. Granzyme B (GZB) expression, and interleukin-10, interferon-γ, tumor necrosis factor-α (TNF-α), IL-4, and IL-5 production by in vitro anti-CD3/CD28- and anti-CD3/CD46-activated CD4+ T cells, and percentage of peripheral Treg (CD4+CD25hi Foxp3hi ) cells were measured by flow cytometry. Wheezing was assessed every 6 months. Recurrent wheezing was defined as three or more episodes following the initial RSV bronchiolitis. RESULTS: Sixty-seven percent (n = 111) of children had wheezing after their initial RSV infection, with 30% having recurrent wheezing. The percentage of peripheral Treg (CD4+CD25hi Foxp3hi ) cells was not significantly different between the wheezing groups. Decreased TNF-α production from anti-CD3/CD28- and anti-CD3/CD46- activated CD4+ T cells was observed in the recurrent wheezers, compared with nonwheezers (p = .048 and .03, respectively). There were no significant differences in the GZB+ CD4+ T cells and production of other inflammatory cytokines between these groups. CONCLUSIONS: We demonstrated lower TNF-α production by in vitro stimulated CD4+ T cells during severe RSV bronchiolitis in children that subsequently developed recurrent wheezing, compared with children with no subsequent wheeze. These findings support the role of CD4+ T cell immunity in the development of subsequent wheezing in these children.
Assuntos
Bronquiolite Viral/imunologia , Linfócitos T CD4-Positivos/imunologia , Sons Respiratórios/etiologia , Infecções por Vírus Respiratório Sincicial/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Células Cultivadas , Citocinas/metabolismo , Feminino , Humanos , Lactente , Masculino , Infecções por Vírus Respiratório Sincicial/complicações , Vírus Sinciciais Respiratórios/isolamento & purificaçãoRESUMO
BACKGROUND: Sarcoidosis is a multi-system disease characterized by the presence of non-caseating epithelioid granulomas in affected tissues, including skeletal muscle. These organized collections of immune cells have important pathophysiologic action including cytokine production leading to inflammation as well as enzymatic conversion of cholecalciferol to calcitriol via 1-α hydroxylase. There are limited reports of isolated granulomatous myositis causing hypercalcemia in pediatric patients. Our patient uniquely presented with symptoms from hypercalcemia and renal insufficiency caused by an overwhelming burden of granulomatous myositis in her lower extremities, but was otherwise asymptomatic. CASE PRESENTATION: A 16 year old Caucasian female presented with protracted symptoms of fatigue, nausea and prominent weight loss with laboratory evidence of hypercalcemia and renal insufficiency. She lacked clinical and physical findings of arthritis, weakness, rash, uveitis, fever, lymphadenopathy or respiratory symptoms. After extensive negative investigations, re-examination yielded subtle soft tissue changes in her lower extremities, with striking MRI findings of extensive myositis without correlative weakness or serum enzyme elevation. Biopsy showed the presence of non-caseating epithelioid granulomas and calcium oxalate crystals. The patient responded well to prednisone and methotrexate but relapsed with weaning of steroids. She reachieved remission with addition of adalimumab. CONCLUSIONS: Sarcoidosis should be considered in patients presenting with symptomatic hypercalcemia with no apparent causes and negative routine workup. The absences of decreased muscle strength or elevated muscle enzymes do not preclude the diagnosis of granulomatous myositis.
Assuntos
Adalimumab/administração & dosagem , Granuloma , Hipercalcemia , Metotrexato/administração & dosagem , Miosite , Prednisona/administração & dosagem , Sarcoidose , Adolescente , Antirreumáticos/administração & dosagem , Diagnóstico Diferencial , Feminino , Granuloma/etiologia , Granuloma/patologia , Humanos , Hipercalcemia/diagnóstico , Hipercalcemia/etiologia , Debilidade Muscular/diagnóstico , Debilidade Muscular/etiologia , Miosite/etiologia , Miosite/patologia , Miosite/fisiopatologia , Insuficiência Renal/sangue , Insuficiência Renal/diagnóstico , Insuficiência Renal/etiologia , Sarcoidose/sangue , Sarcoidose/diagnóstico , Sarcoidose/tratamento farmacológico , Sarcoidose/fisiopatologia , Resultado do TratamentoRESUMO
Recent advances in Kawasaki disease have included attempts to define genes involved in its pathogenesis. There have been recent advances in the studies of rheumatic carditis, leading to a better understanding of the mechanism of the disease. Histologic evaluation of patients with neonatal lupus erythematosus has revealed fibrosis with collagen deposition and calcification of the atrioventricular node. Therapy for cardiac involvement in systemic juvenile idiopathic arthritis should involve treatment of the underlying disease and systemic inflammatory state, and typically includes nonsteroidal antiinflammatory drugs, corticosteroids, disease-modifying drugs, and biologic therapies targeting tumor necrosis factor-alpha, interleukin-1, and interleukin-6.