RESUMO
Mutation in nucleophosmin (NPM1) causes relocalization of this normally nucleolar protein to the cytoplasm (NPM1c+). Despite NPM1 mutation being the most common driver mutation in cytogenetically normal adult acute myeloid leukemia (AML), the mechanisms of NPM1c+-induced leukemogenesis remain unclear. Caspase-2 is a proapoptotic protein activated by NPM1 in the nucleolus. Here, we show that caspase-2 is also activated by NPM1c+ in the cytoplasm and DNA damage-induced apoptosis is caspase-2 dependent in NPM1c+ but not in NPM1wt AML cells. Strikingly, in NPM1c+ cells, caspase-2 loss results in profound cell cycle arrest, differentiation, and down-regulation of stem cell pathways that regulate pluripotency including impairment of the AKT/mTORC1 pathways, and inhibition of Rictor cleavage. In contrast, there were minimal differences in proliferation, differentiation, or the transcriptional profile of NPM1wt cells lacking caspase-2. Our results show that caspase-2 is essential for proliferation and self-renewal of AML cells expressing mutated NPM1. This study demonstrates that caspase-2 is a major effector of NPM1c+ function.
Assuntos
Apoptose , Caspase 2 , Proliferação de Células , Leucemia Mieloide Aguda , Mutação , Proteínas Nucleares , Nucleofosmina , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Caspase 2/metabolismo , Caspase 2/genética , Humanos , Animais , Diferenciação Celular , Linhagem Celular Tumoral , Autorrenovação Celular/genética , Camundongos , Dano ao DNARESUMO
BACKGROUND: In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity. OBJECTIVE: This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants. METHODS: We identified 191 patients from 33 countries with 72 unique mutations. Inclusion criteria included symptoms of immune dysregulation and a biochemically confirmed germline heterozygous GOF variant in STAT3. RESULTS: Overall survival was 88%, median age at onset of symptoms was 2.3 years, and median age at diagnosis was 12 years. Immune dysregulatory features were present in all patients: lymphoproliferation was the most common manifestation (73%); increased frequencies of double-negative (CD4-CD8-) T cells were found in 83% of patients tested. Autoimmune cytopenias were the second most common clinical manifestation (67%), followed by growth delay, enteropathy, skin disease, pulmonary disease, endocrinopathy, arthritis, autoimmune hepatitis, neurologic disease, vasculopathy, renal disease, and malignancy. Infections were reported in 72% of the cohort. A cellular and humoral immunodeficiency was observed in 37% and 51% of patients, respectively. Clinical symptoms dramatically improved in patients treated with JAK inhibitors, while a variety of other immunomodulatory treatment modalities were less efficacious. Thus far, 23 patients have undergone bone marrow transplantation, with a 62% survival rate. CONCLUSION: STAT3 GOF patients present with a wide array of immune-mediated disease including lymphoproliferation, autoimmune cytopenias, and multisystem autoimmunity. Patient care tends to be siloed, without a clear treatment strategy. Thus, early identification and prompt treatment implementation are lifesaving for STAT3 GOF syndrome.
Assuntos
Doenças do Sistema Imunitário , Síndromes de Imunodeficiência , Criança , Humanos , Autoimunidade/genética , Estudos de Coortes , Mutação com Ganho de Função , Síndromes de Imunodeficiência/genética , Mutação , Fator de Transcrição STAT3/genética , Proliferação de Células , LinfócitosRESUMO
BACKGROUND: Lymphocyte differentiation is regulated by coordinated actions of cytokines and signaling pathways. IL-21 activates STAT1, STAT3, and STAT5 and is fundamental for the differentiation of human B cells into memory cells and antibody-secreting cells. While STAT1 is largely nonessential and STAT3 is critical for this process, the role of STAT5 is unknown. OBJECTIVES: This study sought to delineate unique roles of STAT5 in activation and differentiation of human naive and memory B cells. METHODS: STAT activation was assessed by phospho-flow cytometry cell sorting. Differential gene expression was determined by RNA-sequencing and quantitative PCR. The requirement for STAT5B in B-cell and CD4+ T-cell differentiation was assessed using CRISPR-mediated STAT5B deletion from B-cell lines and investigating primary lymphocytes from individuals with germline STAT5B mutations. RESULTS: IL-21 activated STAT5 and strongly induced SOCS3 in human naive, but not memory, B cells. Deletion of STAT5B in B-cell lines diminished IL-21-mediated SOCS3 induction. PBMCs from STAT5B-null individuals contained expanded populations of immunoglobulin class-switched B cells, CD21loTbet+ B cells, and follicular T helper cells. IL-21 induced greater differentiation of STAT5B-deficient B cells into plasmablasts in vitro than B cells from healthy donors, correlating with higher expression levels of transcription factors promoting plasma cell formation. CONCLUSIONS: These findings reveal novel roles for STAT5B in regulating IL-21-induced human B-cell differentiation. This is achieved by inducing SOCS3 to attenuate IL-21 signaling, and BCL6 to repress class switching and plasma cell generation. Thus, STAT5B is critical for restraining IL-21-mediated B-cell differentiation. These findings provide insights into mechanisms underpinning B-cell responses during primary and subsequent antigen encounter and explain autoimmunity and dysfunctional humoral immunity in STAT5B deficiency.
Assuntos
Citocinas , Fator de Transcrição STAT5 , Diferenciação Celular , Citocinas/metabolismo , Homeostase , Humanos , Isotipos de Imunoglobulinas/metabolismo , RNA , Fator de Transcrição STAT5/genética , Fator de Transcrição STAT5/metabolismoRESUMO
The Signal Transducer and Activator of Transcription (STAT)-5 proteins are required in immune regulation and homeostasis and play a crucial role in the development and function of several hematopoietic cells. STAT5b activation is involved in the expression of genes that participate in cell development, proliferation, and survival. STAT5a and STAT5b are paralogs and only human mutations in STAT5B have been identified leading to immune dysregulation and hematopoietic malignant transformation. The inactivating STAT5B mutations cause impaired post-natal growth, recurrent infections and immune dysregulation, whereas gain of function somatic mutations cause dysregulated allergic inflammation. These mutations are rare, and they are associated with a wide spectrum of clinical manifestations which provide a disease model elucidating the biological mechanism of STAT5 by studying the consequences of perturbations in STAT5 activity. Further, the use of Jak inhibitors as therapy for a variety of autoimmune and malignant disorders has increased substantially heading relevant lessons for the consequences of Jak/STAT immunomodulation from the human model. This review summarizes the biology of the STAT5 proteins, human disease associate with molecular defects in STAT5b, and the connection between aberrant activation of STAT5b and the development of certain cancers.
Assuntos
Fator de Transcrição STAT5 , Humanos , Fator de Transcrição STAT5/metabolismo , FosforilaçãoRESUMO
Human NK cells are comprised of phenotypic subsets, whose potentially unique functions remain largely unexplored. C-X-C-motif-chemokine-receptor-6 (CXCR6) + NK cells have been identified as phenotypically immature tissue-resident NK cells in mice and humans. A small fraction of peripheral blood (PB)-NK cells also expresses CXCR6. However, prior reports about their phenotypic and functional plasticity are conflicting. In this study, we isolated, expanded, and phenotypically and functionally evaluated CXCR6+ and CXCR6- PB-NK cells, and contrasted results to bulk liver and spleen NK cells. We found that CXCR6+ and CXCR6- PB-NK cells preserved their distinct phenotypic profiles throughout 14 days of in vitro expansion ("day 14"), after which phenotypically immature CXCR6+ PB-NK cells became functionally equivalent to CXCR6- PB-NK cells. Despite a consistent reduction in CD16 expression and enhanced expression of the transcription factor Eomesodermin (Eomes), day 14 CXCR6+ PB-NK cells had superior antibody-dependent cellular cytotoxicity (ADCC) compared to CXCR6- PB-NK cells. Further, bulk liver NK cells responded to IL-15, but not IL-2 stimulation, with STAT-5 phosphorylation. In contrast, bulk splenic and PB-NK cells robustly responded to both cytokines. Our findings may allow for the selection of superior NK cell subsets for infusion products increasingly used to treat human diseases.
Assuntos
Biomarcadores , Plasticidade Celular , Imunofenotipagem , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Receptores CXCR6/metabolismo , Citotoxicidade Celular Dependente de Anticorpos , Degranulação Celular/imunologia , Linhagem Celular , Plasticidade Celular/genética , Plasticidade Celular/imunologia , Citocinas/metabolismo , Citotoxicidade Imunológica , Humanos , Especificidade de Órgãos/imunologia , Fosforilação , Fator de Transcrição STAT5/metabolismoRESUMO
Immunodeficiency often coincides with hyperactive immune disorders such as autoimmunity, lymphoproliferation, or atopy, but this coincidence is rarely understood on a molecular level. We describe five patients from four families with immunodeficiency coupled with atopy, lymphoproliferation, and cytokine overproduction harboring mutations in NCKAP1L, which encodes the hematopoietic-specific HEM1 protein. These mutations cause the loss of the HEM1 protein and the WAVE regulatory complex (WRC) or disrupt binding to the WRC regulator, Arf1, thereby impairing actin polymerization, synapse formation, and immune cell migration. Diminished cortical actin networks caused by WRC loss led to uncontrolled cytokine release and immune hyperresponsiveness. HEM1 loss also blocked mechanistic target of rapamycin complex 2 (mTORC2)-dependent AKT phosphorylation, T cell proliferation, and selected effector functions, leading to immunodeficiency. Thus, the evolutionarily conserved HEM1 protein simultaneously regulates filamentous actin (F-actin) and mTORC2 signaling to achieve equipoise in immune responses.
Assuntos
Actinas/metabolismo , Citocinas/biossíntese , Síndromes de Imunodeficiência/genética , Transtornos Linfoproliferativos/genética , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Proteínas de Membrana/fisiologia , Fator 1 de Ribosilação do ADP/metabolismo , Linfócitos T CD4-Positivos/imunologia , Proliferação de Células , Humanos , Síndromes de Imunodeficiência/imunologia , Transtornos Linfoproliferativos/imunologia , Proteínas de Membrana/genética , Linhagem , Fosforilação , Família de Proteínas da Síndrome de Wiskott-Aldrich/química , Família de Proteínas da Síndrome de Wiskott-Aldrich/metabolismoRESUMO
Patients with common variable immunodeficiency associated with autoimmune cytopenia (CVID+AIC) generate few isotype-switched B cells with severely decreased frequencies of somatic hypermutations (SHMs), but their underlying molecular defects remain poorly characterized. We identified a CVID+AIC patient who displays a rare homozygous missense M466V mutation in ß-catenin-like protein 1 (CTNNBL1). Because CTNNBL1 binds activation-induced cytidine deaminase (AID) that catalyzes SHM, we tested AID interactions with the CTNNBL1 M466V variant. We found that the M466V mutation interfered with the association of CTNNBL1 with AID, resulting in decreased AID in the nuclei of patient EBV-transformed B cell lines and of CTNNBL1 466V/V Ramos B cells engineered to express only CTNNBL1 M466V using CRISPR/Cas9 technology. As a consequence, the scarce IgG+ memory B cells from the CTNNBL1 466V/V patient showed a low SHM frequency that averaged 6.7 mutations compared with about 18 mutations per clone in healthy-donor counterparts. In addition, CTNNBL1 466V/V Ramos B cells displayed a decreased incidence of SHM that was reduced by half compared with parental WT Ramos B cells, demonstrating that the CTNNBL1 M466V mutation is responsible for defective SHM induction. We conclude that CTNNBL1 plays an important role in regulating AID-dependent antibody diversification in humans.
Assuntos
Proteínas Reguladoras de Apoptose , Linfócitos B , Imunodeficiência de Variável Comum , Homozigoto , Memória Imunológica/genética , Mutação de Sentido Incorreto , Proteínas Nucleares , Hipermutação Somática de Imunoglobulina , Substituição de Aminoácidos , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/imunologia , Linfócitos B/imunologia , Linfócitos B/patologia , Linhagem Celular , Pré-Escolar , Imunodeficiência de Variável Comum/genética , Imunodeficiência de Variável Comum/imunologia , Imunodeficiência de Variável Comum/patologia , Citidina Desaminase/genética , Citidina Desaminase/imunologia , Feminino , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/imunologiaRESUMO
BACKGROUND: Patients with signal transducer and activator of transcription 5b (STAT5b) deficiency have impairment in T-cell homeostasis and natural killer (NK) cells which leads to autoimmunity, recurrent infections, and combined immune deficiency. OBJECTIVE: In this study we characterized the NK cell defect in STAT5b-deficient human NK cells, as well as Stat5b-/- mice. METHODS: We used multiparametric flow cytometry, functional NK cell assays, microscopy, and a Stat5b-/- mouse model to elucidate the effect of impaired and/or absent STAT5b on NK cell development and function. RESULTS: This alteration generated a nonfunctional CD56bright NK cell subset characterized by low cytokine production. The CD56dim NK cell subset had decreased expression of perforin and CD16 and a greater frequency of cells expressing markers of immature NK cells. We observed low NK cell numbers and impaired NK cell maturation, suggesting that STAT5b is involved in terminal NK cell maturation in Stat5b-/- mice. Furthermore, human STAT5b-deficient NK cells had low cytolytic capacity, and fixed-cell microscopy showed poor convergence of lytic granules. This was accompanied by decreased expression of costimulatory and activating receptors. Interestingly, granule convergence and cytolytic function were restored after IL-2 stimulation. CONCLUSIONS: Our results show that in addition to the impaired terminal maturation of NK cells, human STAT5b mutation leads to impairments in early activation events in NK cell lytic synapse formation. Our data provide further insight into NK cell defects caused by STAT5b deficiency.
Assuntos
Imunidade Celular , Sinapses Imunológicas/imunologia , Células Matadoras Naturais/imunologia , Mutação , Fator de Transcrição STAT5/imunologia , Animais , Feminino , Humanos , Sinapses Imunológicas/genética , Células Matadoras Naturais/patologia , Masculino , Camundongos , Camundongos Knockout , Fator de Transcrição STAT5/genéticaRESUMO
Nuclear factor kappa-B subunit 2 (NF-κB2/p100/p52), encoded by NFKB2 (MIM: 164012) belongs to the NF-κB family of transcription factors that play a critical role in inflammation, immunity, cell proliferation, differentiation and survival. Heterozygous C-terminal mutations in NFKB2 have been associated with early-onset common variable immunodeficiency (CVID), central adrenal insufficiency and ectodermal dysplasia. Only two previously reported cases have documented decreased natural killer (NK) cell cytotoxicity, and little is known about the role of NF-κB2 in NK cell maturation and function. Here we report a 13-year-old female that presented at 6 years of age with a history of early onset recurrent sinopulmonary infections, progressive hair loss, and hypogamaglobulinemia consistent with a clinical diagnosis of CVID. At 9 years of age she had cytomegalovirus (CMV) pneumonia that responded to ganciclovir treatment. Functional NK cell testing demonstrated decreased NK cell cytotoxicity despite normal NK cell numbers, consistent with a greater susceptibility to systemic CMV infection. Research exome sequencing (ES) was performed and revealed a novel de novo heterozygous nonsense mutation in NFKB2 (c.2611C>T, p.Gln871*) that was not carried by either of her parents. The variant was Sanger sequenced and confirmed to be de novo in the patient. At age 12, she presented with a reactivation of the systemic CMV infection that was associated with severe and progressive nephrotic syndrome with histologic evidence of pedicellar effacement and negative immunofluorescence. To our knowledge, this is the third NF-κB2 deficient patient in which an abnormal NK cell function has been observed, suggesting a role for non-canonical NF-κB2 signaling in NK cell cytotoxicity. NK cell function should be assessed in patients with mutations in the non-canonical NF-κB pathway to explore the risk for systemic viral infections that may lead to severe complications and impact patient survival. Similarly NF-κB2 should be considered in patients with combined immunodeficiency who have aberrant NK cell function. Further studies are needed to characterize the role of NF-κB2 in NK cell cytotoxic function.
RESUMO
In this report, we describe a novel T437N STAT1 mutation found in a mother and 3 of her 4 children which we demonstrate yields gain-of-function. All of the four patients with the T437N STAT1 mutation experienced lymphadenopathy. However, two of the children developed Nodular Lymphocyte Predominant Hodgkin Lymphoma (NHLPL) and have responded to chemotherapeutic regimens. The fourth sibling had neither the STAT1 variant nor lymphadenopathy or malignancy. To our knowledge this is the first description of a potential association between STAT1 GOF mutations and lymphoma development.
RESUMO
Autosomal dominant hyper-IgE syndrome caused by mutations in the transcription factor STAT3 (AD-HIES) is characterized by a collection of immunologic and non-immune features including eczema, recurrent infections, elevated IgE levels, and connective tissue anomalies. We report the case of a Qatari child with a history of recurrent staphylococcal skin infections since infancy, who was found to have a novel, de novo mutation in STAT3 (c.1934T>A, p.L645Q). The absence of mucocutaneous candidiasis and undetectable IgE levels until the age of 7 years prolonged the time to molecular confirmation of the cause for the patient's immune deficiency. STAT3 p.L645Q was found to have decreased transcriptional capacity. The patient also had low levels of Th17 cells and STAT3 phosphorylation was impaired in patient-derived cells. Nearly 100 unique mutations in STAT3 have been reported in association with AD-HIES.
RESUMO
The section heading that reads PI3K100δ Deficiency should be corrected to read PI3K110δ Deficiency.
RESUMO
NK cells are important early effectors in the innate immune response to a variety of viral infections and for elimination of tumor cells. The JAK/STAT signaling cascade is critical for NK cell development, maturation, survival, and proliferation, therefore, it is important to understand the role of this pathway in NK cell biology. Many cytokines can activate multiple JAK/STAT protein family members, creating a severe phenotype when mutations impair their function or expression. Here we discuss the impact of defective JAK/STAT signaling pathways on NK cell development, activation and cytotoxicity.
Assuntos
Janus Quinases/imunologia , Células Matadoras Naturais/imunologia , Fatores de Transcrição STAT/imunologia , Animais , Humanos , Imunidade Inata/imunologia , Transdução de Sinais/imunologiaRESUMO
PURPOSE OF REVIEW: Natural killer cells are innate lymphoid cells (ILCs) that play critical roles in human host defense and are especially useful in combating viral pathogens and malignancy. RECENT FINDINGS: The NK cell deficiency (NKD) is particularly underscored in patients with a congenital immunodeficiency in which NK cell development or function is affected. The classical NK cell deficiency (cNKD) is a result of absent or a profound decrease in the number of circulating NK cells. In contrast, functional NKD (fNKD) is characterized by abnormal NK cell function but with normal number of NK cells. The combined immune deficiencies with significant impact on NK cells are not considered classical or functional NK cell deficiencies. In these disorders, the impairment of NK cells represents an important aspect of the overall immunodeficiency. In turn, this leads to improved insights on the NK cell development and function. Here, we detail the NK cell biology based upon recent natural killer cell defects described in combined immune deficiencies.
Assuntos
Síndromes de Imunodeficiência/imunologia , Células Matadoras Naturais/imunologia , HumanosAssuntos
Mutação com Ganho de Função , Predisposição Genética para Doença , Fator de Transcrição STAT1/genética , Imunodeficiência Combinada Severa/diagnóstico , Imunodeficiência Combinada Severa/genética , Candidíase Mucocutânea Crônica/etiologia , Análise Mutacional de DNA , Feminino , Estudos de Associação Genética , Transplante de Células-Tronco Hematopoéticas , Heterozigoto , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Linhagem , Fenótipo , Imunodeficiência Combinada Severa/complicações , Imunodeficiência Combinada Severa/terapia , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
BACKGROUND: Heterozygous gain-of-function mutations in PI3K110δ lead to lymphadenopathy, lymphoid hyperplasia, EBV and cytomegalovirus viremia, and sinopulmonary infections. OBJECTIVE: The known role of natural killer (NK) cell function in the control of EBV and cytomegalovirus prompted us to investigate the functional and phenotypic effects of PI3K110δ mutations on NK cell subsets and cytotoxic function. METHODS: Mutations in patients were identified by using whole-exome or targeted sequencing. We performed NK cell phenotyping and functional analysis of patients' cells using flow cytometry, standard Cr51 cytotoxicity assays, and quantitative confocal microscopy. RESULTS: PI3K110δ mutations led to an altered NK cell developmental phenotype and cytotoxic dysfunction. Impaired NK cell cytotoxicity was due to decreased conjugate formation with susceptible target cells and abrogated activation of cell machinery required for target cell killing. These defects were restored partially after initiation of treatment with rapamycin in 3 patients. CONCLUSION: We describe novel NK cell functional deficiency caused by PI3K110δ mutation, which is a likely contributor to the severe viremia observed in these patients. Rapamycin treatment partially restores NK cell function, providing a further rationale for its use in patients with this disease.
Assuntos
Infecções por Citomegalovirus/genética , Citomegalovirus/fisiologia , Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/fisiologia , Síndromes de Imunodeficiência/genética , Células Matadoras Naturais/fisiologia , Mutação/genética , Fosfatidilinositol 3-Quinases/genética , Sirolimo/uso terapêutico , Diferenciação Celular , Células Cultivadas , Classe I de Fosfatidilinositol 3-Quinases , Citotoxicidade Imunológica/efeitos dos fármacos , Heterozigoto , Humanos , Síndromes de Imunodeficiência/tratamento farmacológico , Sinapses Imunológicas/metabolismo , Imunofenotipagem , Ativação Linfocitária , Microscopia Confocal , Viremia , Sequenciamento do ExomaRESUMO
BACKGROUND: Natural killer (NK) cells are critical innate effector cells whose development is dependent on the Janus kinase-signal transducer and activator of transcription (STAT) pathway. NK cell deficiency can result in severe or refractory viral infections. Patients with STAT1 gain-of-function (GOF) mutations have increased viral susceptibility. OBJECTIVE: We sought to investigate NK cell function in patients with STAT1 GOF mutations. METHODS: NK cell phenotype and function were determined in 16 patients with STAT1 GOF mutations. NK cell lines expressing patients' mutations were generated with clustered regularly interspaced short palindromic repeats (CRISPR-Cas9)-mediated gene editing. NK cells from patients with STAT1 GOF mutations were treated in vitro with ruxolitinib. RESULTS: Peripheral blood NK cells from patients with STAT1 GOF mutations had impaired terminal maturation. Specifically, patients with STAT1 GOF mutations have immature CD56dim NK cells with decreased expression of CD16, perforin, CD57, and impaired cytolytic function. STAT1 phosphorylation was increased, but STAT5 was aberrantly phosphorylated in response to IL-2 stimulation. Upstream inhibition of STAT1 signaling with the small-molecule Janus kinase 1/2 inhibitor ruxolitinib in vitro and in vivo restored perforin expression in CD56dim NK cells and partially restored NK cell cytotoxic function. CONCLUSIONS: Properly regulated STAT1 signaling is critical for NK cell maturation and function. Modulation of increased STAT1 phosphorylation with ruxolitinib is an important option for therapeutic intervention in patients with STAT1 GOF mutations.
Assuntos
Síndromes de Imunodeficiência/imunologia , Células Matadoras Naturais/efeitos dos fármacos , Pirazóis/farmacologia , Fator de Transcrição STAT1/genética , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Mutação com Ganho de Função , Humanos , Síndromes de Imunodeficiência/tratamento farmacológico , Síndromes de Imunodeficiência/genética , Janus Quinases/antagonistas & inibidores , Células Matadoras Naturais/imunologia , Masculino , Nitrilas , PirimidinasRESUMO
Natural killer (NK) cells are critical in immune defense against infected, stressed or transformed cells. Their function is regulated by the heterogeneous expression of a wide array of surface receptors that shape its phenotypic diversity. Although NK cells develop in the bone marrow and secondary lymphoid tissues, substantive differentiation is apparent in the peripheral blood including known age-related variation. In order to gain greater insight into phenotypic and functional variation within peripheral blood NK cells across age groups, we used multi-parametric, polyfunctional flow cytometry to interrogate the NK cell variability in 20 healthy adults and 15 5-10, 11-15 and 16-20 year-old children. We found that the normative ranges in both adults and children displayed great inter-individual variation for most markers. While the expression of several receptors did not differ, among those that did, the majority of the differences existed between adults and the three pediatric groups, rather than among children of different ages. Interestingly, we also identified variation in the individual expression of some markers by sex and ethnicity. Combinatorial analysis of NK cell receptors revealed intermediate subsets between the CD56bright and CD56dim NK cells. Furthermore, on examining the NK cell diversity by age, adults were discovered to have the lowest developmental diversity. Thus, our findings identify previously unappreciated NK cell subsets potentially distinguishing children from adults and suggest functional correlates that may have relevance in age-specific host defense.
Assuntos
Imunofenotipagem , Células Matadoras Naturais/metabolismo , Adolescente , Adulto , Fatores Etários , Antígeno CD56/metabolismo , Criança , Análise por Conglomerados , Feminino , Citometria de Fluxo , Humanos , Células Matadoras Naturais/citologia , Células Matadoras Naturais/imunologia , Leucócitos Mononucleares/citologia , Pessoa de Meia-Idade , Receptores de Células Matadoras Naturais/metabolismo , Adulto JovemRESUMO
Common Variable Immunodeficiency (CVID) is a primary immunodeficiency characterized by B cell dysfunction and decreased serum immunoglobulin. CVID patients are classified by the absence or presence of memory B cells. In addition, T cell defects have been demonstrated in only a proportion of CVID patients. The aim of this study was to evaluate the function of CD4(+) T cells from CVID patients and its association with memory B cells. Patients were classified according to their Freiburg groups: group Ia and Ib, with decreased switched memory B cells (<0.4 of PBL), and group II, with normal B cell subsets. Their T cell function was evaluated after stimulation. We observed normal and even increased CD4(+) T cell proliferation in group Ia (p=0.0277). The proliferation positively correlated with the clinical severity score (r=0.4796). We observed lower levels of IL-17A and IL-10 in group Ia (p=0.0177, 0.0109) and Ib (p=0.0009, 0.0084) patients. Group Ib patients also had low levels of IL-13 and IL-9 (p=0.0169, 0.010). Group II patients had similar cytokine production to that of the controls. BAFFR expression was reduced in groups Ia (p=0.0001) and Ib (p=0.0002) and showed an inverse correlation with the severity score (p=0.0262; r=0.5371). ICOS expression was reduced in group Ia (p=0.0364), and PD-1 was increased in group Ib (p=0.0432) patients. This study shows a selective impairment in cytokine production in group Ia patients, which was more extensive than in group Ib patients. The impairment was associated with BAFFR expression in B cells, with ICOS and PD-1 in T cells and, remarkably, with the absence of memory B cells and with the disease severity. Our results suggest that the evaluation of cytokine expression by T cells in combination with the study of B cell memory could be important for understand the pathogenesis of CVID patients.
Assuntos
Receptor do Fator Ativador de Células B/imunologia , Linfócitos B/imunologia , Imunodeficiência de Variável Comum/imunologia , Memória Imunológica , Proteína Coestimuladora de Linfócitos T Induzíveis/imunologia , Receptor de Morte Celular Programada 1/imunologia , Linfócitos T/imunologia , Adulto , Idoso , Receptor do Fator Ativador de Células B/genética , Linfócitos B/patologia , Antígeno B7-H1/genética , Antígeno B7-H1/imunologia , Antígeno CTLA-4/genética , Antígeno CTLA-4/imunologia , Proliferação de Células , Imunodeficiência de Variável Comum/genética , Imunodeficiência de Variável Comum/patologia , Estudos Transversais , Feminino , Regulação da Expressão Gênica , Humanos , Proteína Coestimuladora de Linfócitos T Induzíveis/genética , Interleucina-10/genética , Interleucina-10/imunologia , Interleucina-13/genética , Interleucina-13/imunologia , Interleucina-17/genética , Interleucina-17/imunologia , Interleucina-9/genética , Interleucina-9/imunologia , Ativação Linfocitária , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Cultura Primária de Células , Receptor de Morte Celular Programada 1/genética , Índice de Gravidade de Doença , Transdução de Sinais , Linfócitos T/patologiaRESUMO
The X-linked hyper-IgM syndrome (XHIGM) is the most common form of HIGM. Patients are clinically diagnosed on the basis of recurrent sinopulmonary infections, accompanied with low levels of IgG and IgA, normal to elevated levels of IgM, and the presence of peripheral B cells. Here, we have reported a novel deletion of four nucleotides in CD40LG exon 3, c.375_378delCAAA, which led to a frameshift mutation with a premature stop codon, p.Asn101*126. The deletion resulted in a truncated protein, in which majority of the extracellular domain was lost. However, detection of surface CD40L was still possible as the intracellular, transmembrane, and part of the extracellular domains were not affected. This indicated that this mutation did not affect protein stability and that immunodetection of CD40L expression is not enough for the diagnosis of XHIGM. Our study strongly suggests that genetic diagnosis for XHIGM should always be performed when clinical data support this diagnosis and CD40L protein is present.