RESUMEN
BACKGROUND: Autoimmune diseases are leading causes of ill health and morbidity and have diverse etiology. Two signaling pathways are key drivers of autoimmune pathology, interferon and nuclear factor-κB (NF-κB)/RelA, defining the 2 broad labels of interferonopathies and relopathies. Prior work has established that genetic loss of function of the NF-κB subunit RelB leads to autoimmune and inflammatory pathology in mice and humans. OBJECTIVE: We sought to characterize RelB-deficient autoimmunity by unbiased profiling of the responses of immune sentinel cells to stimulus and to determine the functional role of dysregulated gene programs in the RelB-deficient pathology. METHODS: Transcriptomic profiling was performed on fibroblasts and dendritic cells derived from patients with RelB deficiency and knockout mice, and transcriptomic responses and pathology were assessed in mice deficient in both RelB and the type I interferon receptor. RESULTS: We found that loss of RelB in patient-derived fibroblasts and mouse myeloid cells results in elevated induction of hundreds of interferon-stimulated genes. Removing hyperexpression of the interferon-stimulated gene program did not ameliorate the autoimmune pathology of RelB knockout mice. Instead, we found that RelB suppresses a different set of inflammatory response genes in a manner that is independent of interferon signaling but associated with NF-κB binding motifs. CONCLUSION: Although transcriptomic profiling would describe RelB-deficient autoimmune disease as an interferonopathy, the genetic evidence indicates that the pathology in mice is interferon-independent.
Asunto(s)
Enfermedades Autoinmunes , FN-kappa B , Animales , Humanos , Ratones , Enfermedades Autoinmunes/genética , Interferones/genética , Ratones Noqueados , FN-kappa B/metabolismo , Transducción de Señal , Factor de Transcripción ReIB/genéticaRESUMEN
BACKGROUND: Genetic aberrations in the NFκB pathway lead to primary immunodeficiencies with various degrees of severity. We previously demonstrated that complete ablation of the RelB transcription factor, a key component of the alternative pathway, results in an early manifested combined immunodeficiency requiring stem cell transplantation. OBJECTIVE: To study the molecular basis of a progressive severe autoimmunity and immunodeficiency in three patients. METHODS: Whole exome sequencing was performed to identify the genetic defect. Molecular and cellular techniques were utilized to assess the variant impact on NFκB signaling, canonical and alternative pathway crosstalk, as well as the resultant effects on immune function. RESULTS: Patients presented with multiple autoimmune progressive severe manifestations encompassing the liver, gut, lung, and skin, becoming debilitating in the second decade of life. This was accompanied by a deterioration of the immune system, demonstrating an age-related decline in naïve T cells and responses to mitogens, accompanied by a gradual loss of all circulating CD19+ cells. Whole exome sequencing identified a novel homozygous c. C1091T (P364L) transition in RELB. The P364L RelB protein was unstable, with extremely low expression, but retained some function and could be transiently and partially upregulated following Toll-like receptor stimulation. Stimulation of P364L patient fibroblasts resulted in a marked rise in a cluster of pro-inflammatory hyper-expressed transcripts consistent with the removal of RelB inhibitory effect on RelA function. This is likely the main driver of autoimmune manifestations in these patients. CONCLUSION: Incomplete loss of RelB provided a unique opportunity to gain insights into NFκB's pathway interactions as well as the pathogenesis of autoimmunity. The P364L RelB mutation leads to gradual decline in immune function with progression of severe debilitating autoimmunity.
Asunto(s)
Enfermedades Autoinmunes , Factor de Transcripción ReIB , Humanos , Factor de Transcripción ReIB/genética , Factor de Transcripción ReIB/metabolismo , FN-kappa B/metabolismo , Transducción de Señal , Regulación de la Expresión Génica , Enfermedades Autoinmunes/genéticaRESUMEN
Vertebrate genomes contain major (>99.5%) and minor (<0.5%) introns that are spliced by the major and minor spliceosomes, respectively. Major intron splicing follows the exon-definition model, whereby major spliceosome components first assemble across exons. However, since most genes with minor introns predominately consist of major introns, formation of exon-definition complexes in these genes would require interaction between the major and minor spliceosomes. Here, we report that minor spliceosome protein U11-59K binds to the major spliceosome U2AF complex, thereby supporting a model in which the minor spliceosome interacts with the major spliceosome across an exon to regulate the splicing of minor introns. Inhibition of minor spliceosome snRNAs and U11-59K disrupted exon-bridging interactions, leading to exon skipping by the major spliceosome. The resulting aberrant isoforms contained a premature stop codon, yet were not subjected to nonsense-mediated decay, but rather bound to polysomes. Importantly, we detected elevated levels of these alternatively spliced transcripts in individuals with minor spliceosome-related diseases such as Roifman syndrome, Lowry-Wood syndrome and early-onset cerebellar ataxia. In all, we report that the minor spliceosome informs splicing by the major spliceosome through exon-definition interactions and show that minor spliceosome inhibition results in aberrant alternative splicing in disease.
Asunto(s)
Empalme Alternativo , Exones , Intrones , Empalmosomas/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis/metabolismo , Cardiomiopatías/genética , Células Cultivadas , Ataxia Cerebelosa/genética , Trastornos del Crecimiento/genética , Humanos , Discapacidad Intelectual/genética , Discapacidad Intelectual Ligada al Cromosoma X/genética , Ratones , Microcefalia/genética , Degradación de ARNm Mediada por Codón sin Sentido , Osteocondrodisplasias/genética , Polirribosomas/metabolismo , Enfermedades de Inmunodeficiencia Primaria/genética , ARN Nuclear Pequeño/antagonistas & inhibidores , Enfermedades de la Retina/genética , Factores de Transcripción/metabolismoRESUMEN
BACKGROUND: STAT1 gain-of-function (GOF) is an immune dysregulatory disorder with poorly studied genotype-phenotype correlation, impeding prognostication and early intervention. Given previous mechanistic studies, as well as anecdotal clinical reports, we sought to systematically determine whether DNA-binding domain (DBD) mutations in STAT1 result in a different phenotype than mutations in other gene domains. METHODS: Negative prognostic features previously identified by the International STAT1 GOF Study Group (invasive infections, intracranial aneurysms, and malignancy), as well as other clinical features and mortality, were compared within a cohort of 30 patients with STAT1 GOF diagnosed at our center, consisting of 9 patients with DBD mutations and 21 patients with non-DBD mutations. We subsequently re-analyzed mortality data from a large, previously-published 274-patient cohort by the International STAT1 GOF Study Group. RESULTS: While no differences were noted with respect to malignancy or symptomatic aneurysms, invasive /opportunistic infections were substantially more common among DBD patients, as were sinopulmonary infections, bronchiectasis, enteropathy, endocrinopathies, lymphoproliferative manifestations, and recurrent fevers/HLH. DBD patients also had a lower probability of survival and younger age of mortality compared with non-DBD patients. Our re-evaluation of the published data from the International STAT1 GOF Study Group revealed a similar finding of earlier mortality among patients harboring DBD mutations. CONCLUSION: We report that STAT1 GOF patients with DBD mutations may be regarded as a unique subgroup, impacted more by early-onset profound combined immunodeficiency and with earlier mortality. These findings may impact clinical decision making with respect to early intervention, and in particular hematopoietic stem cell transplant considerations, in such patients.
Asunto(s)
ADN , Mutación con Ganancia de Función , Estudios de Asociación Genética , Humanos , Mutación , Fenotipo , Factor de Transcripción STAT1/genética , Factor de Transcripción STAT1/metabolismoRESUMEN
BACKGROUND: Genetic faults in several components of the nuclear factor-κB pathway cause immunodeficiency. Most defects lead to combined immunodeficiency with a range of severity. Heterozygous mutations in NFKB1 were associated with common variable immunodeficiency, however, homozygous mutations have not been described. OBJECTIVE: We studied the molecular basis of combined immunodeficiency in a patient who presented with failure to thrive, persistent EBV viremia and hepatitis, pneumocystis jirovecii pneumonitis, and generalized lymphadenopathy. METHODS: Whole genome and exome sequencing followed by Sanger confirmation were performed to identify the genetic defect. Molecular and cellular techniques were used to assess the variant impact on the nuclear factor-κB pathway and lymphocyte function. RESULTS: Genetic analysis revealed a novel homozygous mutation in NFKB1, c.2878G>A, p.Gly960Arg (G960R). This affected p105 phosphorylation and p50 formation on antigen and cytokine stimulation, as well as attenuating nuclear signal transmission. As a result, both T- and B-cell maturation and function were perturbed. The number of memory CD4+ T cells were reduced, while CD8+ T cells consisted predominately of expanded differentiated populations. The function of T cells were diminished as shown by reduced responses to mitogens as well as diminished cytokine secretion. B-cell maturation was also affected, with decreased IgD+CD27+ memory B cells while transitional B cells were increased, likely contributing to the reduced ability to produce specific antibodies. CONCLUSION: Homozygous G960R mutation in NFKB1 leads to a severe clinical presentation of combined immunodeficiency. This was associated with blockade of nuclear factor-κB pathway signaling, resulting in aberrations in T- and B-cell maturation and function.
Asunto(s)
Subunidad p50 de NF-kappa B/genética , Inmunodeficiencia Combinada Grave/genética , Homocigoto , Humanos , Lactante , Masculino , Mutación , LinajeRESUMEN
BACKGROUND & AIMS: A proportion of infants and young children with inflammatory bowel diseases (IBDs) have subtypes associated with a single gene variant (monogenic IBD). We aimed to determine the prevalence of monogenic disease in a cohort of pediatric patients with IBD. METHODS: We performed whole-exome sequencing analyses of blood samples from an unselected cohort of 1005 children with IBD, aged 0-18 years (median age at diagnosis, 11.96 years) at a single center in Canada and their family members (2305 samples total). Variants believed to cause IBD were validated using Sanger sequencing. Biopsies from patients were analyzed by immunofluorescence and histochemical analyses. RESULTS: We identified 40 rare variants associated with 21 monogenic genes among 31 of the 1005 children with IBD (including 5 variants in XIAP, 3 in DOCK8, and 2 each in FOXP3, GUCY2C, and LRBA). These variants occurred in 7.8% of children younger than 6 years and 2.3% of children aged 6-18 years. Of the 17 patients with monogenic Crohn's disease, 35% had abdominal pain, 24% had nonbloody loose stool, 18% had vomiting, 18% had weight loss, and 5% had intermittent bloody loose stool. The 14 patients with monogenic ulcerative colitis or IBD-unclassified received their diagnosis at a younger age, and their most predominant feature was bloody loose stool (78%). Features associated with monogenic IBD, compared to cases of IBD not associated with a single variant, were age of onset younger than 2 years (odds ratio [OR], 6.30; P = .020), family history of autoimmune disease (OR, 5.12; P = .002), extra-intestinal manifestations (OR, 15.36; P < .0001), and surgery (OR, 3.42; P = .042). Seventeen patients had variants in genes that could be corrected with allogeneic hematopoietic stem cell transplantation. CONCLUSIONS: In whole-exome sequencing analyses of more than 1000 children with IBD at a single center, we found that 3% had rare variants in genes previously associated with pediatric IBD. These were associated with different IBD phenotypes, and 1% of the patients had variants that could be potentially corrected with allogeneic hematopoietic stem cell transplantation. Monogenic IBD is rare, but should be considered in analysis of all patients with pediatric onset of IBD.
Asunto(s)
Colitis Ulcerosa/genética , Enfermedad de Crohn/genética , Secuenciación del Exoma , Variación Genética , Adolescente , Factores de Edad , Productos Biológicos/uso terapéutico , Niño , Preescolar , Colitis Ulcerosa/diagnóstico , Colitis Ulcerosa/epidemiología , Colitis Ulcerosa/terapia , Enfermedad de Crohn/diagnóstico , Enfermedad de Crohn/epidemiología , Enfermedad de Crohn/terapia , Femenino , Predisposición Genética a la Enfermedad , Trasplante de Células Madre Hematopoyéticas , Humanos , Lactante , Recién Nacido , Masculino , Ontario/epidemiología , Fenotipo , Prevalencia , Medición de Riesgo , Factores de Riesgo , Trasplante Homólogo , Resultado del TratamientoRESUMEN
Minor intron splicing plays a central role in human embryonic development and survival. Indeed, biallelic mutations in RNU4ATAC, transcribed into the minor spliceosomal U4atac snRNA, are responsible for three rare autosomal recessive multimalformation disorders named Taybi-Linder (TALS/MOPD1), Roifman (RFMN), and Lowry-Wood (LWS) syndromes, which associate numerous overlapping signs of varying severity. Although RNA-seq experiments have been conducted on a few RFMN patient cells, none have been performed in TALS, and more generally no in-depth transcriptomic analysis of the â¼700 human genes containing a minor (U12-type) intron had been published as yet. We thus sequenced RNA from cells derived from five skin, three amniotic fluid, and one blood biosamples obtained from seven unrelated TALS cases and from age- and sex-matched controls. This allowed us to describe for the first time the mRNA expression and splicing profile of genes containing U12-type introns, in the context of a functional minor spliceosome. Concerning RNU4ATAC-mutated patients, we show that as expected, they display distinct U12-type intron splicing profiles compared to controls, but that rather unexpectedly mRNA expression levels are mostly unchanged. Furthermore, although U12-type intron missplicing concerns most of the expressed U12 genes, the level of U12-type intron retention is surprisingly low in fibroblasts and amniocytes, and much more pronounced in blood cells. Interestingly, we found several occurrences of introns that can be spliced using either U2, U12, or a combination of both types of splice site consensus sequences, with a shift towards splicing using preferentially U2 sites in TALS patients' cells compared to controls.
Asunto(s)
Enanismo/genética , Retardo del Crecimiento Fetal/genética , Microcefalia/genética , Osteocondrodisplasias/genética , Empalme del ARN/genética , Transcriptoma/genética , Adulto , Anciano , Secuencia de Bases/genética , Preescolar , Secuencia de Consenso/genética , Femenino , Perfilación de la Expresión Génica/métodos , Humanos , Lactante , Intrones/genética , Masculino , Persona de Mediana Edad , ARN/genética , ARN Mensajero/genética , ARN Nuclear Pequeño/genética , Empalmosomas/genética , Adulto JovenRESUMEN
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.
Asunto(s)
Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Heterocigoto , Mutación , Subunidad p50 de NF-kappa B/genética , Fenotipo , Adulto , Anciano , Autoinmunidad/genética , Variación Biológica Poblacional , Biomarcadores , Manejo de la Enfermedad , Femenino , Técnica del Anticuerpo Fluorescente , Estudios de Asociación Genética/métodos , Humanos , Inmunohistoquímica , Estimación de Kaplan-Meier , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Pronóstico , Tomografía Computarizada por Rayos XRESUMEN
INTRODUCTION: Adenosine deaminase (ADA) deficiency causes severe immunodeficiency that is lethal in infancy. Enzyme replacement therapy (ERT) can improve the metabolic, immune and non-immune abnormalities in patients prior to transplantation, however, its benefits over extended periods are not well characterized. We describe a 28-year-old female who received ERT for 27 years. She suffered from EBV negative B cell lymphoma of the hip at 14 years of age and Guillian-Barre Syndrome 2 years later. At 22 years of age, she experienced a gastrointestinal infection with Mycobacterium genavense. At 26 years of age, lymphoma reoccurred with multiple liver lesions followed by Mycobacterium genavense infection with dissemination to the brain. Throughout this period, ADA activity in the plasma was within the therapeutic range. Repeated evaluations demonstrated very low lymphocyte counts and impaired T cell function. CONCLUSIONS: ERT might be insufficient to maintain normal immunity over extended periods in some ADA-deficient patients.
Asunto(s)
Adenosina Desaminasa/deficiencia , Agammaglobulinemia/tratamiento farmacológico , Terapia de Reemplazo Enzimático , Inmunodeficiencia Combinada Grave/tratamiento farmacológico , Adenosina Desaminasa/uso terapéutico , Adulto , Agammaglobulinemia/epidemiología , Femenino , Humanos , Morbilidad , Inmunodeficiencia Combinada Grave/epidemiologíaRESUMEN
Nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) signaling pathways play a key role in various cell processes related to host immunity. The last few years have seen an explosion of disorders associated with NF-κB components from core members of the canonical and noncanonical cascades to adaptor protein and ubiquitination-related enzymes. Disease phenotypes have extended beyond susceptibility to infections and include autoimmunity, lymphoproliferation, atopy, and inflammation. Concurrently, studies are unveiling a tightly regulated system marked by extensive cross-talk between the canonical and noncanonical pathways, as well as among the NF-κB and other signaling pathways. As the rate of discovery in the realm of NF-κB defects accelerates, this review presents a timely summary of major known defects causing human disease, as well as diagnostic, therapeutic, and research challenges and opportunities.
Asunto(s)
Enfermedades del Sistema Inmune/metabolismo , Trastornos Linfoproliferativos/metabolismo , FN-kappa B/metabolismo , Animales , Autoinmunidad , Humanos , Inmunidad , Inflamación , Fenotipo , Receptores de Cinasa C Activada , Receptores Inmunológicos/metabolismo , Transducción de SeñalRESUMEN
BACKGROUND: We previously reported a novel syndrome characterized by combined immunodeficiency associated with severe developmental defects-subsequently known as Roifman-Chitayat syndrome (RCS; OMIM 613328). Linkage analysis identified 2 disease-associated loci. OBJECTIVES: We sought to identify the genetic defect in these patients and characterize their immunologic cellular abnormalities. METHODS: Genetic, immunologic, protein, and cellular functional analyses were used to identify and characterize patient genetic deficiencies and aberrant patient cell behavior. RESULTS: Deleterious variants were found at both loci identified by linkage analysis: a homozygous stop codon in PI3-kinase p110δ (PIK3CD) and a homozygous frame shift mutation in SKAP (KNSTRN), both ablating protein expression. Patients with RCS display aberrant B-cell development, similar to p110δ-deficient mice, but also aberrant T-cell spreading, cell-cell interaction, and migration. Patients also display significant developmental abnormalities not seen in p110δ knockouts (eg, optic nerve atrophy and skeletal anomalies) that we ascribe to loss of SKAP. Aberrant SKAP expression can prolong anaphase and this may contribute to developmental defects. However, we also identified microtubule-associated protein 4 microtubule-binding protein as a novel SKAP-binding partner and show that it undergoes relocalization in patient T cells, with associated areas of aberrant microtubule hyperstabilization, likely contributing not only to the altered properties of RCS lymphoid cells but also to developmental defects. CONCLUSIONS: The complex RCS presentation, with combined developmental and immunologic defects, is associated with a combined deficiency of 2 genes products, PI3-kinase p110δ and SKAP, both of which appear to play a significant role in the disease.
Asunto(s)
Linfocitos B/inmunología , Enfermedades del Desarrollo Óseo/genética , Linfocitos T CD4-Positivos/inmunología , Proteínas de Ciclo Celular/genética , Fosfatidilinositol 3-Quinasa Clase I/genética , Síndromes de Inmunodeficiencia/genética , Proteínas Asociadas a Microtúbulos/genética , Enfermedades del Nervio Óptico/genética , Eliminación de Secuencia/genética , Adolescente , Ciclo Celular/genética , Diferenciación Celular/genética , Línea Celular , Preescolar , Discapacidades del Desarrollo/genética , Facies , Femenino , Humanos , Inmunofenotipificación , Lactante , Linaje , Enfermedades de Inmunodeficiencia Primaria , Hermanos , Secuenciación Completa del Genoma , Adulto JovenRESUMEN
BACKGROUND: Combined immunodeficiency (CID) is a T-cell defect frequently presenting with recurrent infections, as well as associated immune dysregulation manifesting as autoimmunity or allergic inflammation. OBJECTIVE: We sought to identify the genetic aberration in 4 related patients with CID, early-onset asthma, eczema, and food allergies, as well as autoimmunity. METHODS: We performed whole-exome sequencing, followed by Sanger confirmation, assessment of the genetic variant effect on cell signaling, and evaluation of the resultant immune function. RESULTS: A heterozygous novel c.C88T 1-bp substitution resulting in amino acid change R30W in caspase activation and recruitment domain family member 11 (CARD11) was identified by using whole-exome sequencing and segregated perfectly to family members with severe atopy only but was not found in healthy subjects. We demonstrate that the R30W mutation results in loss of function while also exerting a dominant negative effect on wild-type CARD11. The CARD11 defect altered the classical nuclear factor κB pathway, resulting in poor in vitro T-cell responses to mitogens and antigens caused by reduced secretion of IFN-γ and IL-2. CONCLUSION: Unlike patients with biallelic mutations in CARD11 causing severe CID, the R30W defect results in a less profound yet prominent susceptibility to infections, as well as multiorgan atopy and autoimmunity.
Asunto(s)
Proteínas Adaptadoras de Señalización CARD/genética , Proteínas Adaptadoras de Señalización CARD/inmunología , Guanilato Ciclasa/genética , Guanilato Ciclasa/inmunología , Síndromes de Inmunodeficiencia/genética , Síndromes de Inmunodeficiencia/inmunología , Adulto , Proteínas Adaptadoras de Señalización CARD/deficiencia , Preescolar , Femenino , Guanilato Ciclasa/deficiencia , Humanos , Interferón gamma/genética , Interleucina-2/genética , Masculino , Mutación , FN-kappa B/genética , Estudios Prospectivos , Estudios Retrospectivos , Transducción de Señal/genética , Transducción de Señal/inmunología , Linfocitos T/inmunología , Secuenciación del Exoma/métodosRESUMEN
BACKGROUND: Gain-of-function (GOF) mutations in signal transducer and activator of transcription 1 (STAT1) cause susceptibility to a range of infections, autoimmunity, immune dysregulation, and combined immunodeficiency. Disease manifestations can be mild or severe and life-threatening. Hematopoietic stem cell transplantation (HSCT) has been used in some patients with more severe symptoms to treat and cure the disorder. However, the outcome of HSCT for this disorder is not well established. OBJECTIVE: We sought to aggregate the worldwide experience of HSCT in patients with GOF-STAT1 mutations and to assess outcomes, including donor engraftment, overall survival, graft-versus-host disease, and transplant-related complications. METHODS: Data were collected from an international cohort of 15 patients with GOF-STAT1 mutations who had undergone HSCT using a variety of conditioning regimens and donor sources. Retrospective data collection allowed the outcome of transplantation to be assessed. In vitro functional testing was performed to confirm that each of the identified STAT1 variants was in fact a GOF mutation. RESULTS: Primary donor engraftment in this cohort of 15 patients with GOF-STAT1 mutations was 74%, and overall survival was only 40%. Secondary graft failure was common (50%), and posttransplantation event-free survival was poor (10% by 100 days). A subset of patients had hemophagocytic lymphohistiocytosis before transplant, contributing to their poor outcomes. CONCLUSION: Our data indicate that HSCT for patients with GOF-STAT1 mutations is curative but has significant risk of secondary graft failure and death.
Asunto(s)
Mutación con Ganancia de Función , Predisposición Genética a la Enfermedad , Enfermedad Injerto contra Huésped/genética , Enfermedad Injerto contra Huésped/mortalidad , Trasplante de Células Madre Hematopoyéticas , Factor de Transcripción STAT1/genética , Aloinjertos , Supervivencia sin Enfermedad , Femenino , Enfermedad Injerto contra Huésped/inmunología , Humanos , Masculino , Estudios Retrospectivos , Factores de Riesgo , Factor de Transcripción STAT1/inmunología , Tasa de SupervivenciaRESUMEN
BACKGROUND & AIMS: Severe forms of inflammatory bowel disease (IBD) that develop in very young children can be caused by variants in a single gene. We performed whole-exome sequence (WES) analysis to identify genetic factors that might cause granulomatous colitis and severe perianal disease, with recurrent bacterial and viral infections, in an infant of consanguineous parents. METHODS: We performed targeted WES analysis of DNA collected from the patient and her parents. We validated our findings by a similar analysis of DNA from 150 patients with very-early-onset IBD not associated with known genetic factors analyzed in Toronto, Oxford, and Munich. We compared gene expression signatures in inflamed vs noninflamed intestinal and rectal tissues collected from patients with treatment-resistant Crohn's disease who participated in a trial of ustekinumab. We performed functional studies of identified variants in primary cells from patients and cell culture. RESULTS: We identified a homozygous variant in the tripartite motif containing 22 gene (TRIM22) of the patient, as well as in 2 patients with a disease similar phenotype. Functional studies showed that the variant disrupted the ability of TRIM22 to regulate nucleotide binding oligomerization domain containing 2 (NOD2)-dependent activation of interferon-beta signaling and nuclear factor-κB. Computational studies demonstrated a correlation between the TRIM22-NOD2 network and signaling pathways and genetic factors associated very early onset and adult-onset IBD. TRIM22 is also associated with antiviral and mycobacterial effectors and markers of inflammation, such as fecal calprotectin, C-reactive protein, and Crohn's disease activity index scores. CONCLUSIONS: In WES and targeted exome sequence analyses of an infant with severe IBD characterized by granulomatous colitis and severe perianal disease, we identified a homozygous variant of TRIM22 that affects the ability of its product to regulate NOD2. Combined computational and functional studies showed that the TRIM22-NOD2 network regulates antiviral and antibacterial signaling pathways that contribute to inflammation. Further study of this network could lead to new disease markers and therapeutic targets for patients with very early and adult-onset IBD.
Asunto(s)
Enfermedad de Crohn/genética , Variación Genética , Antígenos de Histocompatibilidad Menor/genética , Proteína Adaptadora de Señalización NOD2/metabolismo , Proteínas Represoras/genética , Transducción de Señal , Proteínas de Motivos Tripartitos/genética , Edad de Inicio , Australia , Células Cultivadas , Biología Computacional , Consanguinidad , Enfermedad de Crohn/diagnóstico , Enfermedad de Crohn/metabolismo , Enfermedad de Crohn/terapia , Bases de Datos Genéticas , Inglaterra , Exoma , Femenino , Perfilación de la Expresión Génica/métodos , Redes Reguladoras de Genes , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Alemania , Homocigoto , Humanos , Recién Nacido , Antígenos de Histocompatibilidad Menor/metabolismo , Ontario , Linaje , Fenotipo , Mapas de Interacción de Proteínas , Proteínas Represoras/metabolismo , Índice de Severidad de la Enfermedad , Transfección , Proteínas de Motivos Tripartitos/metabolismoRESUMEN
Primary effusion lymphoma (PEL) is a rare lymphoma that occurs more frequently in immunocompromised adults and has a poor survival. We report a 9-year-old female with combined immunodeficiency with an Epstein-Barr virus positive/human herpes virus 8 negative PEL-like lymphoma. The treatment with systemic chemotherapy for non-Hodgkin lymphoma, zidovudine, and interferon-α failed to control disease progression. This is the first reported pediatric case of PEL-like lymphoma. Increased diagnostic awareness and more effective treatment strategies are needed for this rare lymphoma.
Asunto(s)
Síndromes de Inmunodeficiencia/complicaciones , Linfoma de Efusión Primaria/etiología , Niño , Femenino , Humanos , Síndromes de Inmunodeficiencia/congénito , Linfoma de Efusión Primaria/diagnóstico , Linfoma de Efusión Primaria/tratamiento farmacológicoRESUMEN
X-linked severe combined immunodeficiency (X-SCID) leads to a T(-) NK(-) B(+) immunophenotype and is caused by mutations in the gene encoding the IL-2 receptor γ-chain (IL2RG). IL2RG(R222C) leads to atypical SCID with a severe early onset phenotype despite largely normal NK- and T-cell numbers. To address this discrepancy, we performed a detailed analysis of T, B, and NK cells, including quantitative STAT phosphorylation and functional responses to the cytokines IL-2, IL-4, IL-15, and IL-21 in a patient with the IL2RG(R222C) mutation. Moreover, we identified nine additional unpublished patients with the same mutations, all with a full SCID phenotype, and confirmed selected immunological observations. T-cell development was variably affected, but led to borderline T-cell receptor excision circle (TREC) levels and a normal repertoire. T cells showed moderately reduced proliferation, failing enhancement by IL-2. While NK-cell development was normal, IL-2 enhancement of NK-cell degranulation and IL-15-induced cytokine production were absent. IL-2 or IL-21 failed to enhance B-cell proliferation and plasmablast differentiation. These functional alterations were reflected by a differential impact of IL2RG(R222C) on cytokine signal transduction, with a gradient IL-4Asunto(s)
Linfocitos B/inmunología
, Citocinas/inmunología
, Subunidad gamma Común de Receptores de Interleucina/genética
, Células Asesinas Naturales/inmunología
, Inmunodeficiencia Combinada Grave/inmunología
, Linfocitos T/inmunología
, Humanos
, Lactante
, Subunidad gamma Común de Receptores de Interleucina/inmunología
, Activación de Linfocitos/genética
, Activación de Linfocitos/inmunología
, Masculino
, Mutación
, Fenotipo
, Transducción de Señal/inmunología
RESUMEN
Multiple receptors that control cell growth and inflammation activate the NFκB pathway that comprises of two pathways. Dysfunction of the classical pathway leads to impaired adaptive and innate immunity in humans. In contrast the exact role of the alternative NFκB pathway mediated by RelB in humans remains largely elusive. We have recently identified deleterious mutations in RelB in patients with combined immunodeficiency and autoimmunity. We studied here the biological effects of RelB deficiency on the immune system. We show that the thymus in this patient is dysplastic and consequently new thymus emigrants are rare and there is an accumulation of CD45 RO(+) T cells with an increase in CD62L(+) central memory cells. The TCR repertoire of these cells appears skewed with selective clonal expansion. In vitro responses to T cell mitogens were markedly depressed and so were PHA induced IL2 and IFNγ production. In addition, the TH1 promoting T bet and STAT1 were reduced. In contrast, hyper-activation was seen in response to anti-CD3 and CD28. T cell dependent antibody responses were low to absent in all patients. We found that BAFF-R was reduced and CD40 signaling aberrant. Critically, CD27(+) memory cells were absent. We have shown here for the first time the role of RelB on lymphocyte development in humans. In the absence of RelB, B cells development is arrested, resulting in poor production of immunoglobulins and specific antibodies. T cell maturation in the thymus appears altered with reduced output and production of a skewed T cell repertoire with expansion of clones which are likely the cause of the autoimmune features observed in these patients.