The clinical, immunological and genetic features of 12 Chinese patients with STAT3 mutations

Gene-Smoking Interaction Analysis for the Identification of Novel Asthma-Associated Genetic Factors

Asthma is a complex heterogeneous disease caused by gene-environment interactions. Although numerous genome-wide association studies have been conducted, these interactions have not been systemically investigated. We sought to identify genetic factors associated with the asthma phenotype in 66,857 subjects from the Health Examination Study, Cardiovascular Disease Association Study, and Korea Association Resource Study cohorts. We investigated asthma-associated gene-environment (smoking status) interactions at the level of single nucleotide polymorphisms, genes, and gene sets. We identified two potentially novel (SETDB1 and ZNF8) and five previously reported (DM4C, DOCK8, MMP20, MYL7, and ADCY9) genes associated with increased asthma risk. Numerous gene ontology processes, including regulation of T cell differentiation in the thymus (GO:0033081), were significantly enriched for asthma risk. Functional annotation analysis confirmed the causal relationship between five genes (two potentially novel and three previously reported genes) and asthma through genome-wide functional prediction scores (combined annotation-dependent depletion, deleterious annotation of genetic variants using neural networks, and RegulomeDB). Our findings elucidate the genetic architecture of asthma and improve the understanding of its biological mechanisms. However, further studies are necessary for developing preventive treatments based on environmental factors and understanding the immune system mechanisms that contribute to the etiology of asthma.

Inherited human ZNF341 deficiency

Typical hyper-IgE syndromes (HIES) are caused by autosomal-dominant-negative (DN) variants of STAT3 (Signal Transducer And Activator Of Transcription 3) or IL6ST (Interleukin 6 Cytokine Family Signal Transducer), biallelic partial loss-of-function (LOF) variants of IL6ST, or biallelic complete LOF variants of ZNF341 (Zinc Finger Protein 341). Including the two new cases described in this review, only 20 patients with autosomal-recessive (AR) ZNF341 deficiency have ever been reported. Patients with AR ZNF341 deficiency have clinical and immunological phenotypes resembling those of patients with autosomal-dominant STAT3 deficiency, but with a usually milder clinical presentation and lower NK (Natural Killer) cell counts. ZNF341-deficient cells have 50% the normal level of STAT3 in the resting state. However, as there is no clear evidence that STAT3 haploinsufficiency causes HIES, this decrease alone is probably insufficient to explain the HIES phenotype observed in the ZNF341-deficient patients. The combination of decreased basal expression level and impaired autoinduction of STAT3 observed in ZNF341-deficient lymphocytes is considered a more likely pathophysiological mechanism. We review here what is currently known about the ZNF341 gene and ZNF341 deficiency, and briefly discuss possible roles for this protein in addition to its control of STAT3 activity.

Inborn errors of human transcription factors governing IFN-γ antimycobacterial immunity

Inborn errors of immunity (IEI) delineate redundant and essential defense mechanisms in humans. We review 15 autosomal-dominant (AD) or -recessive (AR) IEI involving 11 transcription factors (TFs) and impairing interferon-gamma (IFN-γ) immunity, conferring a predisposition to mycobacterial diseases. We consider three mechanism-based categories: 1) IEI mainly affecting myeloid compartment development (AD GATA2 and AR and AD IRF8 deficiencies), 2) IEI mainly affecting lymphoid compartment development (AR FOXN1, AR PAX1, AR RORγ/RORγT, AR T-bet, AR c-Rel, AD STAT3 gain-of-function (GOF), and loss-of-function (LOF) deficiencies), and 3) IEI mainly affecting myeloid and/or lymphoid function (AR and AD STAT1 LOF, AD STAT1 GOF, AR IRF1, and AD NFKB1 deficiencies). We discuss the contribution of the discovery and study of inborn errors of TFs essential for host defense against mycobacteria to molecular and cellular analyses of human IFN-γ immunity.

A human STAT3 gain-of-function variant confers T cell dysregulation without predominant Treg dysfunction in mice

Primary immune regulatory disorders (PIRD) represent a group of disorders characterized by immune dysregulation, presenting with a wide range of clinical disease, including autoimmunity, autoinflammation, or lymphoproliferation. Autosomal dominant germline gain-of-function (GOF) variants in STAT3 result in a PIRD with a broad clinical spectrum. Studies in patients have documented a decreased frequency of FOXP3+ Tregs and an increased frequency of Th17 cells in some patients with active disease. However, the mechanisms of disease pathogenesis in STAT3 GOF syndrome remain largely unknown, and treatment is challenging. We developed a knock-in mouse model harboring a de novo pathogenic human STAT3 variant (p.G421R) and found these mice developed T cell dysregulation, lymphoproliferation, and CD4+ Th1 cell skewing. Surprisingly, Treg numbers, phenotype, and function remained largely intact; however, mice had a selective deficiency in the generation of iTregs. In parallel, we performed single-cell RNA-Seq on T cells from STAT3 GOF patients. We demonstrate only minor changes in the Treg transcriptional signature and an expanded, effector CD8+ T cell population. Together, these findings suggest that Tregs are not the primary driver of disease and highlight the importance of preclinical models in the study of disease mechanisms in rare PIRD.

Main human inborn errors of immunity leading to fungal infections

BACKGROUND

The host molecular and genetic features are essential in providing susceptibility to a broad spectrum of fungal infections; most of these do not cause disease in healthy individuals because of mutual benefits with opportunistic fungi besides the host's capacity to control the infections. In contrast, patients with primary immunodeficiency (PID) can develop mild superficial to life-threatening invasive infections. In the last years, thanks to next-generation sequencing (NGS), several inborn-error variants have been discovered in genes encoding protein acting against fungal infections, contributing to better defining the role of innate and adaptive immunity cooperation during infection resolution. Candida fungal infection, that sometimes-striking healthy subjects, is responsible for the chronic mucocutaneous candidiasis (CMC) that is one of the principal clinical manifestations occurring in several rare PIDs associated with an inborn error of IL17-immunity.

OBJECTIVE

This review aimed to provide an overview of CMC-derived genetic defects, including IL17-deficiencies (IL17A, IL17F, IL17RA, IL17RC), STAT1 gain-of-function (GOF)- deficiency, STAT3-HIES and CARD9-deficiency.

SOURCES

We carried out detailed research work to identify interesting articles, commentaries, and reviews in the PubMed literature to ensure a correct and updated for this narrative review.

CONTENT

We propose an in-depth description and an update of genetic and cellular mechanisms underlying fungal infections, focusing on the IL17-mediated response, a report of clinical manifestations and describe therapeutic options.

IMPLICATION

This narrative review will help clinician to identify the correct management of patients based on molecular and cellular findings underlying pathogenic mechanisms of different IEIs. Moreover achieve the genetic diagnosis will be useful to offer genetic counselling intra- and inter-family and to ensure a personalized treatment of patients.

The role of genetics in food allergy

INTRODUCTION

As the prevalence of food allergies (FA) increases worldwide, our understanding of its pathophysiology and risk factors is markedly expanding. In the past decades, an increasing number of genes have been linked to FA. Identification of such genes may help in predicting the genetic risk for FA development, age of onset, clinical manifestation, causative allergen(s), and possibly the optimal treatment strategies. Furthermore, identification of these genetic factors can help to understand the complex interactions between genes and the environment in predisposition to FA.

AREAS COVERED

We outline the recent important progress in determining genetic variants and disease-associated genes in IgE-mediated FA. We focused on the monogenic inborn errors of immunity (IEI) where FA is one of the clinical manifestations, emphasizing the genes and gene variants which were linked to FA with some of the most robust evidence.

EXPERT OPINION

Genetics play a significant role, either directly or along with environmental factors, in the development of FA. Since FA is a multifactorial disease, it is expected that multiple genes and genetic loci contribute to the risk for its development. Identification of the involved genes should contribute to the area of FA regarding pathogenesis, prediction, recognition, prognosis, prevention, and possibly therapeutic interventions.

STAT3 Hyper-IgE Syndrome-an Update and Unanswered Questions

The hyper-IgE syndromes (HIES) are a heterogeneous group of inborn errors of immunity sharing manifestations including increased infection susceptibility, eczema, and raised serum IgE. Since the prototypical HIES description 55 years ago, areas of significant progress have included description of key disease-causing genes and differentiation into clinically distinct entities. The first two patients reported had what is now understood to be HIES from dominant-negative mutations in signal transduction and activator of transcription 3 (STAT3-HIES), conferring a broad immune defect across both innate and acquired arms, as well as defects in skeletal, connective tissue, and vascular function, causing a clinical phenotype including eczema, staphylococcal and fungal skin and pulmonary infection, scoliosis and minimal trauma fractures, and vascular tortuosity and aneurysm. Due to the constitutionally expressed nature of STAT3, initial reports at treatment with allogeneic stem cell transplantation were not positive and treatment has hinged on aggressive antimicrobial prophylaxis and treatment to prevent the development of end-organ disease such as pneumatocele. Research into the pathophysiology of STAT3-HIES has driven understanding of the interface of several signaling pathways, including the JAK-STAT pathways, interleukins 6 and 17, and the role of Th17 lymphocytes, and has been expanded by identification of phenocopies such as mutations in IL6ST and ZNF341. In this review we summarize the published literature on STAT3-HIES, present the diverse clinical manifestations of this syndrome with current management strategies, and update on the uncertain role of stem cell transplantation for this disease. We outline key unanswered questions for further study.

Clinical and Immunological Heterogeneity in Japanese Patients with Gain-of-Function Variants in STAT3

PURPOSE

Germline loss-of-function variants in the signal transducer and activator of transcription 3 (STAT3) gene result in autosomal dominant hyper IgE syndrome, whereas somatic gain-of-function (GOF) variants in STAT3 are associated with some malignancies. In addition, germline GOF variants in STAT3 are linked to disorders involving autoimmunity and lymphoproliferation. In this study, we describe five Japanese families with germline GOF variants in STAT3, including three novel variants. We also present the clinical and immunological characteristics of these patients.

METHODS

Eight patients from five families were enrolled in this study. We performed genetic and immunological analyses, and collected the associated clinical information.

RESULTS

We identified five heterozygous variants in STAT3 using whole-exome sequencing and target gene sequencing. Two of these (E286G and T716M) were previously reported and three (K348E, E415G, and G618A) were novel. A STAT3 reporter assay revealed that all of the variants were GOF. However, the immunological and clinical characteristics among the patients were highly variable.

CONCLUSION

Patients with STAT3 GOF variants exhibited clinical and immunological heterogeneity with incomplete penetrance.

Defective Toll-Like Receptors Driven B Cell Response in Hyper IgE Syndrome Patients With STAT3 Mutations

Autosomal dominant hyper-IgE syndrome (AD-HIES) is a rare inherited primary immunodeficient disease (PIDs), which is caused by STAT3 gene mutations. Previous studies indicated a defective Toll-like receptor (TLR) 9-induced B cell response in AD-HIES patients, including proliferation, and IgG production. However, the other TLRs-mediated B cell responses in AD-HIES patients were not fully elucidated. In this study, we systematically studied the B cell response to TLRs signaling pathways in AD-HIES patients, including proliferation, activation, apoptosis, cytokine, and immunoglobulin production. Our results showed that the TLRs-induced B cell proliferation and activation was significantly impaired in AD-HIES patients. Besides, AD-HIES patients had defects in TLRs-induced B cell class switch, as well as IgG/IgM secretion and IL-10 production in B cells. Taken together, we first systematically reported the deficiency of TLRs driven B cell response in AD-HIES patients, which help to have a better understanding of the pathology of AD-HIES.