RESUMO
Familial forms of hemophagocytic lymphohistiocytosis (HLH) are caused by loss-of-function mutations in genes encoding perforin as well as those required for release of perforin-containing cytotoxic granule constituent. Perforin is expressed by subsets of CD8+ T cells and NK cells, representing lymphocytes that share mechanism of target cell killing yet display distinct modes of target cell recognition. Here, we highlight recent findings concerning the genetics of familial HLH that implicate CD8+ T cells in the pathogenesis of HLH and discuss mechanistic insights from animal models as well as patients that reveal how CD8+ T cells may contribute to or drive disease, at least in part through release of IFN-γ. Intriguingly, CD8+ T cells and NK cells may act differentially in severe hyperinflammatory diseases such as HLH. We also discuss how CD8+ T cells may promote or drive pathology in other cytokine release syndromes (CSS). Moreover, we review the molecular mechanisms underpinning CD8+ T cell-mediated lymphocyte cytotoxicity, key to the development of familial HLH. Together, recent insights to the pathophysiology of CSS in general and HLH in particular are providing promising new therapeutic targets.
Assuntos
Linfócitos T CD8-Positivos , Síndrome da Liberação de Citocina , Linfo-Histiocitose Hemofagocítica , Humanos , Linfócitos T CD8-Positivos/imunologia , Linfo-Histiocitose Hemofagocítica/imunologia , Linfo-Histiocitose Hemofagocítica/genética , Animais , Síndrome da Liberação de Citocina/imunologia , Síndrome da Liberação de Citocina/genética , Células Matadoras Naturais/imunologia , Perforina/genética , Perforina/metabolismo , Citotoxicidade Imunológica/genética , Interferon gama/imunologia , Interferon gama/genética , Interferon gama/metabolismoRESUMO
Current HLH-2004-based diagnostic criteria for familial hemophagocytic lymphohistiocytosis (FHL) are based on expert opinion. Here we performed a case-control study to test and possibly improve these clinical criteria. We also developed two complementary expert opinion-based diagnostic strategies for FHL in patients with signs/symptoms suggestive of HLH, based on genetic and cellular cytotoxicity assays. The cases (n=366) were children <16 years with verified familial and/or genetic FHL (n=341) or Griscelli syndrome type 2 (GS2) (n=25); 276 from the HLH-94/HLH-2004 databases and 90 from the Italian HLH Registry. All fulfilled the HLH-94/HLH-2004 patient inclusion criteria. Controls were 374 children with systemic-onset juvenile idiopathic arthritis (sJIA) and 329+361 children in two cohorts with febrile infections that could be confused with HLH and sepsis, respectively. To provide complete data sets, multiple imputations were performed. The optimal model, based on the number of diagnostic criteria fulfilled from 17 variables studied, reveled almost similar diagnostic thresholds as the existing criteria, with accuracy 99.1% (sensitivity 97.1%; specificity 99.5%). Notably, assessment of the original HLH-2004 criteria revealed accuracy 97.4% (sensitivity 99.0%; specificity 97.1%). Since cellular cytotoxicity assays here constitute a separate diagnostic strategy, HLH-2004 criteria without NK-cell function was also studied which showed accuracy 99.0% (sensitivity 96.2%; specificity 99.5%). Thus, we conclude that the HLH-2004 criteria (without NK-cell function) have significant validity in their current form when tested against severe infections or sJIA. It is important to exclude underlying malignancies and atypical infections. In addition, complementary cellular and genetic diagnostic guidelines can facilitate necessary confirmation of clinical diagnosis.
RESUMO
Natural killer (NK) cells are innate lymphoid cells (ILCs) contributing to immune responses to microbes and tumors. Historically, their classification hinged on a limited array of surface protein markers. Here, we used single-cell RNA sequencing (scRNA-seq) and cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) to dissect the heterogeneity of NK cells. We identified three prominent NK cell subsets in healthy human blood: NK1, NK2 and NK3, further differentiated into six distinct subgroups. Our findings delineate the molecular characteristics, key transcription factors, biological functions, metabolic traits and cytokine responses of each subgroup. These data also suggest two separate ontogenetic origins for NK cells, leading to divergent transcriptional trajectories. Furthermore, we analyzed the distribution of NK cell subsets in the lung, tonsils and intraepithelial lymphocytes isolated from healthy individuals and in 22 tumor types. This standardized terminology aims at fostering clarity and consistency in future research, thereby improving cross-study comparisons.
Assuntos
Células Matadoras Naturais , Análise de Célula Única , Humanos , Análise de Célula Única/métodos , Células Matadoras Naturais/imunologia , Transcriptoma , Neoplasias/imunologia , Subpopulações de Linfócitos/imunologia , Subpopulações de Linfócitos/metabolismo , Tonsila Palatina/imunologia , Tonsila Palatina/citologia , Perfilação da Expressão Gênica , Pulmão/imunologia , Citocinas/metabolismoRESUMO
Primary hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder associated with autosomal recessive variants in genes required for perforin-mediated lymphocyte cytotoxicity. A rapid diagnosis is crucial for successful treatment. Although defective cytotoxic T lymphocyte (CTL) function causes pathogenesis, quantification of natural killer (NK) cell exocytosis triggered by K562 target cells currently represents a standard diagnostic procedure for primary HLH. We have prospectively evaluated different lymphocyte exocytosis assays in 213 patients referred for evaluation for suspected HLH and related hyperinflammatory syndromes. A total of 138 patients received a molecular diagnosis consistent with primary HLH. Compared to routine K562 cell-based assays, assessment of Fc receptor-triggered NK-cell and T cell receptor-triggered CTL exocytosis displayed higher sensitivity and improved specificity for the diagnosis of primary HLH, with these assays combined providing a sensitivity of 100% and specificity of 98.3%. By comparison, NK-cell exocytosis following K562 target cell stimulation displayed a higher inter-individual variability, in part explained by differences in NK-cell differentiation or large functional reductions following shipment. We thus recommend combined analysis of T cell receptor-triggered CTL and Fc receptor-triggered NK-cell exocytosis for the diagnosis of patients with suspected familial HLH or atypical manifestations of congenital defects in lymphocyte exocytosis.
RESUMO
SYNTAXIN-11 (STX11) is a SNARE protein that mediates the fusion of cytotoxic granules with the plasma membrane at the immunological synapses of CD8 T or NK cells. Autosomal recessive inheritance of deleterious STX11 variants impairs cytotoxic granule exocytosis, causing familial hemophagocytic lymphohistiocytosis type 4 (FHL-4). In several FHL-4 patients, we also observed hypogammaglobulinemia, elevated frequencies of naive B cells, and increased double-negative DN2:DN1 B cell ratios, indicating a hitherto unrecognized role of STX11 in humoral immunity. Detailed analysis of Stx11-deficient mice revealed impaired CD4 T cell help for B cells, associated with disrupted germinal center formation, reduced isotype class switching, and low antibody avidity. Mechanistically, Stx11-/- CD4 T cells exhibit impaired membrane fusion leading to reduced CD107a and CD40L surface mobilization and diminished IL-2 and IL-10 secretion. Our findings highlight a critical role of STX11 in SNARE-mediated membrane trafficking and vesicle exocytosis in CD4 T cells, important for successful CD4 T cell-B cell interactions. Deficiency in STX11 impairs CD4 T cell-dependent B cell differentiation and humoral responses.
Assuntos
Linfócitos B , Linfócitos T CD4-Positivos , Proteínas Qa-SNARE , Animais , Proteínas Qa-SNARE/metabolismo , Proteínas Qa-SNARE/genética , Linfócitos B/imunologia , Linfócitos B/metabolismo , Camundongos , Humanos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfo-Histiocitose Hemofagocítica/imunologia , Linfo-Histiocitose Hemofagocítica/genética , Linfo-Histiocitose Hemofagocítica/metabolismo , Camundongos Knockout , Camundongos Endogâmicos C57BL , Feminino , Masculino , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Imunidade Humoral , ExocitoseRESUMO
Multisystem Inflammatory Syndrome in Children (MIS-C) is a severe complication of SARS-CoV-2 infection characterized by multi-organ involvement and inflammation. Testing of cellular function ex vivo to understand the aberrant immune response in MIS-C is limited. Despite strong antibody production in MIS-C, SARS-CoV-2 nucleic acid testing can remain positive for 4-6 weeks after infection. Therefore, we hypothesized that dysfunctional cell-mediated antibody responses downstream of antibody production may be responsible for delayed clearance of viral products in MIS-C. In MIS-C, monocytes were hyperfunctional for phagocytosis and cytokine production, while natural killer (NK) cells were hypofunctional for both killing and cytokine production. The decreased NK cell cytotoxicity correlated with an NK exhaustion marker signature and systemic IL-6 levels. Potentially providing a therapeutic option, cellular engagers of CD16 and SARS-CoV-2 proteins were found to rescue NK cell function in vitro. Together, our results reveal dysregulation in antibody-mediated cellular responses unique to MIS-C that likely contribute to the immune pathology of this disease.
RESUMO
NK cell responsiveness to target cells is tuned by interactions between inhibitory NK cell receptors and their cognate HLA class I ligands in a process termed "NK cell education." Previous studies addressing the role for NK cell education in Ab-dependent cellular cytotoxicity (ADCC) show ambiguous results and do not encompass full educational resolution. In this study, we systematically characterized human NK cell CD16-triggered degranulation toward defined human tumor cell lines in the presence of either the mAb rituximab or a recently developed CD34xCD16 bispecific killer engager. Despite positive correlation between killer Ig-related receptor (KIR)-mediated education and CD16 expression, NK cells educated by one or even two inhibitory KIRs did not perform better in terms of ADCC than uneducated NK cells in either missing-self or KIR-ligand matched settings at saturating Ab concentrations. Instead, NKG2A+ NK cells consistently showed more potent ADCC in the missing-self context despite lower levels of CD16 expression. KIR2DS1+ NK cells demonstrated dampened ADCC in both the missing-self and KIR-ligand matched settings, even in the presence of its ligand HLA C2. The lower response by KIR2DS1+ NK cells was also observed when stimulated with a bispecific killer engager. Surprisingly, repression of ADCC was also observed by NKG2A+ NK cells coexpressing the inhibitory KIR2DL1-C245 receptor that confers weak education. In conclusion, our study suggests that NK cell education by inhibitory KIRs does not augment ADCC per se, whereas expression of KIR2DS1 and KIR2DL1-C245 dominantly represses ADCC. These insights add to the fundamental understanding of NK cells and may have implications for their therapeutic use.
Assuntos
Anticorpos Biespecíficos , Humanos , Degranulação Celular , Ligantes , Receptores KIR , Citotoxicidade Imunológica , Linhagem Celular Tumoral , Receptores KIR2DL1RESUMO
The integrin CD49a marks highly cytotoxic epidermal-tissue-resident memory (TRM) cells, but their differentiation from circulating populations remains poorly defined. We demonstrate enrichment of RUNT family transcription-factor-binding motifs in human epidermal CD8+CD103+CD49a+ TRM cells, paralleled by high RUNX2 and RUNX3 protein expression. Sequencing of paired skin and blood samples revealed clonal overlap between epidermal CD8+CD103+CD49a+ TRM cells and circulating memory CD8+CD45RA-CD62L+ T cells. In vitro stimulation of circulating CD8+CD45RA-CD62L+ T cells with IL-15 and TGF-ß induced CD49a expression and cytotoxic transcriptional profiles in a RUNX2- and RUNX3-dependent manner. We therefore identified a reservoir of circulating cells with cytotoxic TRM potential. In melanoma patients, high RUNX2, but not RUNX3, transcription correlated with a cytotoxic CD8+CD103+CD49a+ TRM cell signature and improved patient survival. Together, our results indicate that combined RUNX2 and RUNX3 activity promotes the differentiation of cytotoxic CD8+CD103+CD49a+ TRM cells, providing immunosurveillance of infected and malignant cells.
Assuntos
Linfócitos T CD8-Positivos , Melanoma , Humanos , Linfócitos T CD8-Positivos/metabolismo , Integrina alfa1/metabolismo , Integrinas/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Memória Imunológica , Antígenos Comuns de Leucócito/metabolismo , Melanoma/metabolismoRESUMO
Innate lymphoid cells (ILCs) are considered innate counterparts of adaptive T cells; however, their common and unique transcriptional signatures in pediatric inflammatory bowel disease (pIBD) are largely unknown. Here, we report a dysregulated colonic ILC composition in pIBD colitis that correlates with inflammatory activity, including accumulation of naive-like CD45RA+CD62L- ILCs. Weighted gene co-expression network analysis (WGCNA) reveals modules of genes that are shared or unique across innate and adaptive lymphocytes. Shared modules include genes associated with activation/tissue residency, naivety/quiescence, and antigen presentation. Lastly, nearest-neighbor-based analysis facilitates the identification of "most inflamed" and "least inflamed" lymphocytes in pIBD colon with unique transcriptional signatures. Our study reveals shared and unique transcriptional signatures of colonic ILCs and T cells in pIBD. We also provide insight into the transcriptional regulation of colonic inflammation, deepening our understanding of the potential mechanisms involved in pIBD.
Assuntos
Colite , Doenças Inflamatórias Intestinais , Humanos , Criança , Linfócitos , Imunidade Inata/genética , Colite/genética , Linfócitos TRESUMO
The networks of transcription factors (TFs) that control intestinal-resident memory CD8+ T (TRM) cells, including multipotency and effector programs, are poorly understood. In this work, we investigated the role of the TF Bcl11b in TRM cells during infection with Listeria monocytogenes using mice with post-activation, conditional deletion of Bcl11b in CD8+ T cells. Conditional deletion of Bcl11b resulted in increased numbers of intestinal TRM cells and their precursors as well as decreased splenic effector and circulating memory cells and precursors. Loss of circulating memory cells was in part due to increased intestinal homing of Bcl11b-/- circulating precursors, with no major alterations in their programs. Bcl11b-/- TRM cells had altered transcriptional programs, with diminished expression of multipotent/multifunctional (MP/MF) program genes, including Tcf7, and up-regulation of the effector program genes, including Prdm1. Bcl11b also limits the expression of Ahr, another TF with a role in intestinal CD8+ TRM cell differentiation. Deregulation of TRM programs translated into a poor recall response despite TRM cell accumulation in the intestine. Reduced expression of MP/MF program genes in Bcl11b-/- TRM cells was linked to decreased chromatin accessibility and a reduction in activating histone marks at these loci. In contrast, the effector program genes displayed increased activating epigenetic status. These findings demonstrate that Bcl11b is a frontrunner in the tissue residency program of intestinal memory cells upstream of Tcf1 and Blimp1, promoting multipotency and restricting the effector program.
Assuntos
Linfócitos T CD8-Positivos , Fatores de Transcrição , Camundongos , Animais , Linfócitos T CD8-Positivos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Diferenciação Celular , Intestinos , Proteínas Supressoras de Tumor/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismoRESUMO
BACKGROUND: We previously reported that impaired type I IFN activity, due to inborn errors of TLR3- and TLR7-dependent type I interferon (IFN) immunity or to autoantibodies against type I IFN, account for 15-20% of cases of life-threatening COVID-19 in unvaccinated patients. Therefore, the determinants of life-threatening COVID-19 remain to be identified in ~ 80% of cases. METHODS: We report here a genome-wide rare variant burden association analysis in 3269 unvaccinated patients with life-threatening COVID-19, and 1373 unvaccinated SARS-CoV-2-infected individuals without pneumonia. Among the 928 patients tested for autoantibodies against type I IFN, a quarter (234) were positive and were excluded. RESULTS: No gene reached genome-wide significance. Under a recessive model, the most significant gene with at-risk variants was TLR7, with an OR of 27.68 (95%CI 1.5-528.7, P = 1.1 × 10-4) for biochemically loss-of-function (bLOF) variants. We replicated the enrichment in rare predicted LOF (pLOF) variants at 13 influenza susceptibility loci involved in TLR3-dependent type I IFN immunity (OR = 3.70[95%CI 1.3-8.2], P = 2.1 × 10-4). This enrichment was further strengthened by (1) adding the recently reported TYK2 and TLR7 COVID-19 loci, particularly under a recessive model (OR = 19.65[95%CI 2.1-2635.4], P = 3.4 × 10-3), and (2) considering as pLOF branchpoint variants with potentially strong impacts on splicing among the 15 loci (OR = 4.40[9%CI 2.3-8.4], P = 7.7 × 10-8). Finally, the patients with pLOF/bLOF variants at these 15 loci were significantly younger (mean age [SD] = 43.3 [20.3] years) than the other patients (56.0 [17.3] years; P = 1.68 × 10-5). CONCLUSIONS: Rare variants of TLR3- and TLR7-dependent type I IFN immunity genes can underlie life-threatening COVID-19, particularly with recessive inheritance, in patients under 60 years old.
Assuntos
COVID-19 , Interferon Tipo I , Humanos , Adulto Jovem , Adulto , Pessoa de Meia-Idade , SARS-CoV-2 , Receptor 3 Toll-Like/genética , Receptor 7 Toll-Like , AutoanticorposRESUMO
Natural killer (NK) cells recognize virally infected cells and tumors. NK cell function depends on balanced signaling from activating receptors, recognizing products from tumors or viruses, and inhibitory receptors (such as KIR/Ly49), which recognize major histocompatibility complex class I (MHC-I) molecules. KIR/Ly49 signaling preserves tolerance to self but also conveys reactivity toward MHC-I-low target cells in a process known as NK cell education. Here, we found that NK cell tolerance and education were determined by the subcellular localization of the tyrosine phosphatase SHP-1. In mice lacking MHC-I molecules, uneducated, self-tolerant Ly49A+ NK cells showed accumulation of SHP-1 in the activating immune synapse, where it colocalized with F-actin and the signaling adaptor protein SLP-76. Education of Ly49A+ NK cells by the MHC-I molecule H2Dd led to reduced synaptic accumulation of SHP-1, accompanied by augmented signaling from activating receptors. Education was also linked to reduced transcription of Ptpn6, which encodes SHP-1. Moreover, synaptic SHP-1 accumulation was reduced in NK cells carrying the H2Dd-educated receptor Ly49G2 but not in those carrying the noneducating receptor Ly49I. Colocalization of Ly49A and SHP-1 outside of the synapse was more frequent in educated compared with uneducated NK cells, suggesting a role for Ly49A in preventing synaptic SHP-1 accumulation in NK cell education. Thus, distinct patterning of SHP-1 in the activating NK cell synapse may determine NK cell tolerance.
Assuntos
Antígenos Ly , Células Matadoras Naturais , Camundongos , Animais , Receptores Semelhantes a Lectina de Células NK/metabolismo , Antígenos Ly/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , Sinapses/metabolismoRESUMO
SAMD9 and SAMD9L encode homologous interferon-induced genes that can inhibit cellular translation as well as proliferation and can restrict viral replication. Gain-of-function (GoF) variants in these ancient, yet rapidly evolving genes are associated with life-threatening disease in humans. Potentially driving population sequence diversity, several viruses have evolved host range factors that antagonize cell-intrinsic SAMD9/SAMD9L function. Here, to gain insights into the molecular regulation of SAMD9/SAMD9L activity and to explore the prospect of directly counteracting the activity of pathogenic variants, we examined whether dysregulated activity of pathogenic SAMD9/SAMD9L variants can be modulated by the poxviral host range factors M062, C7 and K1 in a co-expression system. We established that the virally encoded proteins retain interactions with select SAMD9/SAMD9L missense GoF variants. Furthermore, expression of M062, C7 and K1 could principally ameliorate the translation-inhibiting and growth-restrictive effect instigated by ectopically expressed SAMD9/SAMD9L GoF variants, yet with differences in potency. K1 displayed the greatest potency and almost completely restored cellular proliferation and translation in cells co-expressing SAMD9/SAMD9L GoF variants. However, neither of the viral proteins tested could antagonize a truncated SAMD9L variant associated with severe autoinflammation. Our study demonstrates that pathogenic SAMD9/SAMD9L missense variants can principally be targeted through molecular interactions, opening an opportunity for therapeutic modulation of their activity. Moreover, it provides novel insights into the complex intramolecular regulation of SAMD9/SAMD9L activity.
Assuntos
Especificidade de Hospedeiro , Proteínas Supressoras de Tumor , Humanos , Proteínas Supressoras de Tumor/genética , Proteínas Virais/genética , Fatores de Transcrição , Replicação Viral/genética , Peptídeos e Proteínas de Sinalização Intracelular/genéticaRESUMO
Background: We previously reported inborn errors of TLR3- and TLR7-dependent type I interferon (IFN) immunity in 1-5% of unvaccinated patients with life-threatening COVID-19, and auto-antibodies against type I IFN in another 15-20% of cases. Methods: We report here a genome-wide rare variant burden association analysis in 3,269 unvaccinated patients with life-threatening COVID-19 (1,301 previously reported and 1,968 new patients), and 1,373 unvaccinated SARS-CoV-2-infected individuals without pneumonia. A quarter of the patients tested had antibodies against type I IFN (234 of 928) and were excluded from the analysis. Results: No gene reached genome-wide significance. Under a recessive model, the most significant gene with at-risk variants was TLR7 , with an OR of 27.68 (95%CI:1.5-528.7, P= 1.1×10 -4 ), in analyses restricted to biochemically loss-of-function (bLOF) variants. We replicated the enrichment in rare predicted LOF (pLOF) variants at 13 influenza susceptibility loci involved in TLR3-dependent type I IFN immunity (OR=3.70 [95%CI:1.3-8.2], P= 2.1×10 -4 ). Adding the recently reported TYK2 COVID-19 locus strengthened this enrichment, particularly under a recessive model (OR=19.65 [95%CI:2.1-2635.4]; P= 3.4×10 -3 ). When these 14 loci and TLR7 were considered, all individuals hemizygous ( n =20) or homozygous ( n =5) for pLOF or bLOF variants were patients (OR=39.19 [95%CI:5.2-5037.0], P =4.7×10 -7 ), who also showed an enrichment in heterozygous variants (OR=2.36 [95%CI:1.0-5.9], P =0.02). Finally, the patients with pLOF or bLOF variants at these 15 loci were significantly younger (mean age [SD]=43.3 [20.3] years) than the other patients (56.0 [17.3] years; P= 1.68×10 -5 ). Conclusions: Rare variants of TLR3- and TLR7-dependent type I IFN immunity genes can underlie life-threatening COVID-19, particularly with recessive inheritance, in patients under 60 years old.
RESUMO
Autosomal recessive mutations in RAB27A are associated with Griscelli syndrome type 2 (GS2), characterized by hypopigmentation and development of early-onset, potentially fatal hemophagocytic lymphohistiocytosis (HLH). We describe a 35-year old male who presented with recurrent fever, was diagnosed with Epstein-Barr virus-driven chronic lymphoproliferation, fulfilled clinical HLH criteria, and who carried a novel homozygous RAB27A c.551G > A p.(R184Q) variant. We aimed to evaluate the contribution of the identified RAB27A variant in regard to the clinical phenotype as well as cellular and biochemical function. The patient displayed normal pigmentation as well as RAB27A expression in blood-derived cells. However, patient NK and CD8+ T cell exocytosis was low. Ectopic expression of the RAB27A p.R184Q variant rescued melanosome distribution in mouse Rab27a-deficient melanocytes, but failed to increase exocytosis upon reconstitution of human RAB27A-deficient CD8+ T cells. Mechanistically, the RAB27A p.R184Q variant displayed reduced binding to SLP2A but augmented binding to MUNC13-4, two key effector proteins in immune cells. MUNC13-4 binding was particularly strong to an inactive RAB27A p.T23N/p.R184Q double mutant. RAB27A p.R184Q was expressed and could facilitate melanosome trafficking, but did not support lymphocyte exocytosis. The HLH-associated RAB27A variant increased Munc13-4 binding, potentially representing a novel mode of impairing RAB27A function selectively in hematopoietic cells.
Assuntos
Infecções por Vírus Epstein-Barr , Linfo-Histiocitose Hemofagocítica , Adulto , Humanos , Masculino , Linfócitos T CD8-Positivos , Herpesvirus Humano 4 , Linfo-Histiocitose Hemofagocítica/diagnóstico , Linfo-Histiocitose Hemofagocítica/genética , Ligação Proteica , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/química , Proteínas rab de Ligação ao GTP/metabolismo , Proteínas rab27 de Ligação ao GTP/genética , Proteínas rab27 de Ligação ao GTP/metabolismoRESUMO
Autosomal recessive IRF7 deficiency was previously reported in three patients with single critical influenza or COVID-19 pneumonia episodes. The patients' fibroblasts and plasmacytoid dendritic cells produced no detectable type I and III IFNs, except IFN-ß. Having discovered four new patients, we describe the genetic, immunological, and clinical features of seven IRF7-deficient patients from six families and five ancestries. Five were homozygous and two were compound heterozygous for IRF7 variants. Patients typically had one episode of pulmonary viral disease. Age at onset was surprisingly broad, from 6 mo to 50 yr (mean age 29 yr). The respiratory viruses implicated included SARS-CoV-2, influenza virus, respiratory syncytial virus, and adenovirus. Serological analyses indicated previous infections with many common viruses. Cellular analyses revealed strong antiviral immunity and expanded populations of influenza- and SARS-CoV-2-specific memory CD4+ and CD8+ T cells. IRF7-deficient individuals are prone to viral infections of the respiratory tract but are otherwise healthy, potentially due to residual IFN-ß and compensatory adaptive immunity.