TGFβ receptor mutations impose a strong predisposition for human allergic disease

Advancements in the study of T lymphocytes in thoracic aortic aneurysm and aortic dissection

Thoracic aortic aneurysms and dissection (TAAD) is a critical, life-threatening cardiovascular condition characterized by immune-mediated inflammatory infiltration and structural degradation of the aorta wall, which are pivotal in its etiology. In recent years, the significance of T lymphocytes in TAAD has increasingly garnered scientific attention. TAAD is a multifaceted vascular disorder characterized by the involvement of many immune cells, with T lymphocytes playing a pivotal role, particularly in the modulation of inflammatory responses, immunological control, and tissue damage. A comprehensive understanding of the T lymphocyte activation process in TAAD is crucial for the advancement of novel preventative and therapy strategies. This article evaluates the recent research advancements on the function of T lymphocytes in TAAD, aiming to offer novel insights for the future prevention and treatment of TAAD.

The genetics of hyper IgE syndromes

Hyper IgE syndromes (HIES) form a rare group of primary immunodeficiency disorders (PIDs) distinguished by persistent skin abscesses, dermatitis, allergies, and infections, in addition to their characteristic high serum IgE levels. Autosomal dominant (AD) and autosomal recessive (AR) genetic defects have been reported in HIES. From a clinical perspective, AD-HIES cases generally exhibit several non-immunologic features, including connective tissue, dental and skeletal abnormalities, whilst AR-HIES conditions have a higher incidence of neurologic complications and cutaneous viral infections. Genetic defects associated with HIES lead to impaired immune signaling, affecting pathways crucial for immune cell development, function, and immune response to pathogens/allergens. As a result, HIES patients are predisposed to recurrent bacterial and/or fungal infections, as well as atopic allergic responses. In many cases, the exact biological mechanisms responsible for the variations observed in the clinical phenotypes between the two inherited forms of HIES are still unclear. In this review, we describe the genetic basis of HIES with a distinction between the AR-HIES and AD-HIES forms, to better comprehend the different underlying molecular mechanisms, a distinction which is imperative for the accurate diagnosis, management, and development of targeted therapies for HIES patients.

Cardiovascular complications in vascular connective tissue disorders after COVID-19 infection and vaccination

BACKGROUND

COVID-19 infection and vaccination have been reported to confer an elevated risk for cardiovascular events (CVE). We sought to determine whether individuals with an underlying vascular connective tissue disorder including Marfan syndrome (MFS), Loeys-Dietz syndrome (LDS), or vascular Ehlers Danlos syndrome (vEDS) are at increased risk for cardiac events after COVID-19 infection or vaccination.

METHODS

325 respondents self-reported data through a cross-sectional, web-based survey available from 22 November 2021, through 15 March 2022 regarding COVID-19 illness and vaccinations, the occurrence of any CVE, and adverse events following vaccination. The data were analyzed using a Cox proportional hazards model with time varying indicators for COVID-19 illness/vaccination in the preceding 30 days.

RESULTS

COVID-19 illness was significantly associated with an increased rate of a new abnormal heart rhythm 30 days following infection. No other CVEs were reported in the 90 days after COVID-19 illness. We did not find evidence of an increased rate of any CVE in the 30 days following any COVID-19 vaccination dose.

CONCLUSION

In respondents with MFS, LDS, or vEDS, we uncovered no evidence of an increase in CVEs in the 30 days following COVID-19 illness, with the possible exception of dysrhythmia. In light of the absence of a substantial increase in self-reported CVEs in the 30 days following COVID-19 vaccination, these data are in keeping with the recommendation from the Marfan Foundation Professional Advisory Board that all eligible persons be vaccinated for COVID-19.

Causal relationship between immunophenotypes and mitral valve prolapse: a bidirectional Mendelian randomization study

Background

Emerging evidence indicates a significant link between various immune cell types and the development of heart valve disorders. Mitral valve prolapse (MVP) is a common condition that can lead to heart failure, arrhythmias, and even sudden death. Currently, the role of immune cells in MVP is not well understood. Thus, this study aimed to explore the causal relationship between immunophenotypes and the risk of MVP.

Methods

This study conducted a two-sample Mendelian randomization (MR) analysis to examine the link between 731 immunophenotypes and MVP. Publicly available data from genome-wide association studies were used for both the exposures and outcomes. The primary method for assessing the causal relationship between mitral valve prolapse and the 731 immunophenotypes was the inverse variance weighted method. Additionally, to ensure the MR results were reliable and valid, sensitivity analyses, including leave-one-out analysis, the Cochran Q-test, and the Egger intercept test, were conducted.

Results

The findings indicated that multiple immune cell phenotypes potentially cause changes in the risk of developing MVP. After adjusting for the false discovery rate, nine immune phenotypes were found to increase the risk of MVP, while nine others appeared to decrease it. In addition, reverse MR analysis found no causal relationship between MVP and these eighteen immunophenotypes.

Conclusion

Through genetic analyses, this research demonstrated a significant causal relationship between certain immune cells and MVP, providing new insights for future basic and clinical research.

Cellular and molecular basis of proximal small intestine disorders

The proximal part of the small intestine, including duodenum and jejunum, is not only dedicated to nutrient digestion and absorption but is also a highly regulated immune site exposed to environmental factors. Host-protective responses against pathogens and tolerance to food antigens are essential functions in the small intestine. The cellular ecology and molecular pathways to maintain those functions are complex. Maladaptation is highlighted by common immune-mediated diseases such as coeliac disease, environmental enteric dysfunction or duodenal Crohn's disease. An expanding spectrum of more than 100 rare monogenic disorders inform on causative molecular mechanisms of nutrient absorption, epithelial homeostasis and barrier function, as well as inflammatory immune responses and immune regulation. Here, after summarizing the architectural and cellular traits that underlie the functions of the proximal intestine, we discuss how the integration of tissue immunopathology and molecular mechanisms can contribute towards our understanding of disease and guide diagnosis. We propose an integrated mechanism-based taxonomy and discuss the latest experimental approaches to gain new mechanistic insight into these disorders with large disease burden worldwide as well as implications for therapeutic interventions.

Loss of tolerance to dietary proteins: From mouse models to human model diseases

The critical importance of the immunoregulatory mechanisms, which prevent adverse responses to dietary proteins is demonstrated by the consequences of their failure in two common but distinct human pathological conditions, food allergy and celiac disease. The mechanisms of tolerance to dietary proteins have been extensively studied in mouse models but the extent to which the results in mice can be extrapolated to humans remains unclear. Here, after summarizing the mechanisms known to control oral tolerance in mouse models, we discuss how the monogenic immune disorders associated with food allergy on the one hand, and celiac disease, on the other hand, represent model diseases to gain insight into the key immunoregulatory pathways that control immune responses to food antigens in humans. The spectrum of monogenic disorders, in which the dysfunction of a single gene, is strongly associated with TH2-mediated food allergy suggests an important overlap between the mechanisms that regulate TH2 and IgE responses to food antigens in humans and mice. In contrast, celiac disease provides a unique example of the link between autoimmunity and loss of tolerance to a food antigen.

Insights into the clinical, immunologic, and genetic underpinnings of food allergy

The last few decades have seen striking changes in the field of food allergy. The prevalence of the disease has risen dramatically in many parts of the globe, and management of the condition has undergone major revision. While delayed introduction of common allergenic foods during infancy was advised for many years, the learning early about peanut allergy (LEAP) trial and other studies led to a major shift in infant feeding practices, with deliberate early introduction of these foods now recommended. Additionally, the Food and Drug Administration approved the first treatment for food allergy in 2020-a peanut oral immunotherapy (OIT) product that likely represents just the beginning of new immunotherapy-based and other treatments for food allergy. Our knowledge of the environmental and genetic factors contributing to the pathogenesis of food allergy has also undergone transformational advances. Here, we will discuss our efforts to improve the clinical care of patients with food allergy and our understanding of the immunological mechanisms contributing to this common disease.

Losartan Treatment Reduces Esophageal Eosinophilic Inflammation in a Subset of Eosinophilic Esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic, food antigen-driven esophageal disorder. Connective tissue disorders (CTDs) and esophageal connective tissue alterations are associated with EoE. Therefore, angiotensin II type 1 receptor blockade with losartan, an accepted CTD treatment, is a potential EoE treatment.

OBJECTIVE

We evaluated losartan's effects on esophageal pathology, symptoms, and safety in patients with EoE with and without a CTD in an open-label, non-placebo controlled multisite study.

METHODS

Fifteen participants with EoE, aged 5 to 23 years, underwent treatment with per-protocol titrated doses of losartan in an open-label, 16-week pilot trial. Losartan was added to standard of care therapy and 14 patients completed the study. Eosinophil counts served as the primary end point, whereas we also assessed the EoE Histology Scoring System, Endoscopic Reference Scores, EoE Diagnostic Panel, and patient-reported outcomes.

RESULTS

Esophageal eosinophilia was not reduced after losartan. The peak eosinophil count was not reduced for the proximal (median [interquartile range]: -3 [-22 to 3]; P = .49) and distal esophagus (median [interquartile range]: -18 [-39 to -1]; P = .23). There were no differences in losartan response in EoE with or without CTD (n = 7 and 8, respectively). Regardless, in a small subset of four participants esophageal eosinophilia was resolved with a concomitant reduction in EoE Histology Scoring System score and Endoscopic Reference Score. Across all subjects, the Pediatric EoE Symptom Score, Pediatric Quality of Life Inventory EoE Module, and EoE Diagnostic Panel improved after losartan (P < .05).

CONCLUSIONS

Losartan treatment was associated with improved patient-reported outcome scores and EoE Diagnostic Panel biomarkers although without a reduction in esophageal eosinophilia overall. A subset of patients demonstrated improved histopathologic and endoscopic features that could not be tied to a specific feature predicting response to treatment.

TH2-driven manifestations of inborn errors of immunity

Monogenic lesions in pathways critical for effector functions responsible for immune surveillance, protection against autoinflammation, and appropriate responses to allergens and microorganisms underlie the pathophysiology of inborn errors of immunity (IEI). Variants in cytokine production, cytokine signaling, epithelial barrier function, antigen presentation, receptor signaling, and cellular processes and metabolism can drive autoimmunity, immunodeficiency, and/or allergic inflammation. Identification of these variants has improved our understanding of the role that many of these proteins play in skewing toward TH2-related allergic inflammation. Early-onset or atypical atopic disease, often in conjunction with immunodeficiency and/or autoimmunity, should raise suspicion for an IEI. This becomes a diagnostic dilemma if the initial clinical presentation is solely allergic inflammation, especially when the prevalence of allergic diseases is becoming more common. Genetic sequencing is necessary for IEI diagnosis and is helpful for early recognition and implementation of targeted treatment, if available. Although genetic evaluation is not feasible for all patients with atopy, identifying atopic patients with molecular immune abnormalities may be helpful for diagnostic, therapeutic, and prognostic purposes. In this review, we focus on IEI associated with TH2-driven allergic manifestations and classify them on the basis of the affected molecular pathways and predominant clinical manifestations.

Investigating dysregulation of TGF-β1/SMAD3 signaling in atopic dermatitis: a molecular and immunohistochemical analysis

Atopic dermatitis (AD) is a persistent and recurring inflammatory condition affecting the skin. An expanding corpus of evidence indicates the potential participation of transforming growth factor-β1 (TGF-β1) in the modulation of inflammation and tissue remodeling in AD. The primary objective of this study was to examine the aberrant modulation of TGF-β1/small mothers against decapentaplegic homolog 3 (SMAD3) signaling through a comprehensive analysis of their molecular and protein expression profiles. The study encompassed an aggregate of 37 participants, which included 25 AD patients and 12 controls. The assessment of mRNA and protein levels of TGF-β1 and SMAD3 was conducted utilizing quantitative real-time PCR and immunohistochemistry (IHC), whereas serum IgE and vitamin D levels were estimated by ELISA and chemiluminescence, respectively. Quantitative analysis demonstrated a 2.5-fold upregulation of TGF-β1 mRNA expression in the lesional AD skin (P < 0.0001). IHC also exhibited a comparable augmented pattern, characterized by moderate to strong staining intensities. In addition, TGF-β1 mRNA showed an association with vitamin D deficiency in serum (P < 0.02), and its protein expression was linked with the disease severity (P < 0.01) Furthermore, a significant decrease in the expression of the SMAD3 gene was observed in the affected skin (P = 0.0004). This finding was further confirmed by evaluating the protein expression and phosphorylation of SMAD3, both of which exhibited a decrease. These findings suggest that there is a dysregulation in the TGF-β1/SMAD3 signaling pathway in AD. Furthermore, the observed augmentation in mRNA and protein expression of TGF-β1, along with its correlation with the disease severity, holds considerable clinical significance and emphasizes its potential role in AD pathogenesis.

Methylation-driven mechanisms of allergic rhinitis during pollen and non-pollen seasons using integrated bioinformatics analysis

Background

Allergic rhinitis (AR) is a widespread allergic airway disease that results from a complex interplay between genetic and environmental factors and affects approximately 10%-40% of the global population. Pollen is a common allergen, and exposure to pollen can cause epigenetic changes. However, the mechanism underlying pollen-induced DNA methylation changes and their potential effects on the allergic march are still unclear. The purpose of this study was to explore the methylation-driven mechanisms of AR during the pollen and non-pollen seasons using bioinformatics analysis and to investigate their relationship with asthma.

Methods

We downloaded DNA methylation and gene expression data from the GEO database (GSE50387: GSE50222, GSE50101) and identified differentially methylated positions (DMPs) and differentially expressed genes (DEGs) during the pollen and non-pollen seasons using the CHAMP and limma packages. Through correlation analysis, we identified methylation-driven genes and performed pathway enrichment analysis to annotate their functions. We incorporated external data on AR combined with asthma (GSE101720) for analysis to identify key CpGs that promote the transformation of AR to asthma. We also utilized external data on olive pollen allergy (GSE54522) for analysis to validate the methylation-driven genes. Weighted correlation network analysis (WGCNA) was employed to identify gene modules significantly correlated with pollen allergy. We extracted genes related to the key methylation-driven gene ZNF667-AS1 from the significant module and performed pathway intelligent clustering using KOBAS-i. We also utilized gene set enrichment analysis to explore the potential function of ZNF667-AS1.

Results

We identified 20 and 24 CpG-Gene pairings during the pollen and non-pollen seasons. After incorporating external data from GSE101720, we found that ZNF667-AS1 is a key gene that may facilitate the transformation of AR into asthma during the pollen season. This finding was further validated in another external dataset, GSE54522, which is associated with pollen allergy. WGCNA identified 17 modules, among which the blue module showed significant correlation with allergies. ZNF667-AS1 was located in the blue module. We performed pathway analysis on the genes correlated with ZNF667-AS1 extracted from the blue module and identified a prominent cluster of pathways in the KOBAS-i results, including Toll-like receptor (TLR) family, MyD88, MAPK, and oxidative stress. Gene set enrichment analysis around cg05508084 (paired with ZNF667-AS1) also indicated its potential involvement in initiating and modulating allergic inflammation from the perspective of TLR and MAPK signaling.

Conclusion

We identified methylation-driven genes and their related pathways during the pollen and non-pollen seasons in patients with AR and identified key CpGs that promote the transformation of AR into asthma due to pollen exposure. This study provides new insights into the underlying molecular mechanisms of the transformation of AR to asthma.

Polymorphic markers of several immune regulatory genes modulate the susceptibility for eczema and related phenotypes in children

Background

Eczema is associated with multiple genes regulating epidermal barrier functions and immunological pathways. However, their epistatic interactions are not well studied. This cross-sectional study investigated the relationship between childhood eczema phenotypes and single-nucleotide polymorphisms (SNPs) of immune regulatory genes.

Methods

One thousand three hundred and twenty-nine Chinese eczematous children and 1,179 non-allergic controls were recruited. Nine SNPs of immune regulatory genes signal transducer and activator of transcription 3 (STAT3), interleukin-10 (IL10), transforming growth factor-beta 1 (TGFB1), and IL-6 receptor (IL6R) were genotyped by TaqMan genotyping assays. Logistic regression was used to analyze the associations between SNPs and eczema phenotypes. Generalized multifactor dimensionality reduction (GMDR) was used to examine epistatic interactions among these SNPs as well as those reported by our group [filaggrin (FLG) and 11q13] for eczema phenotypes.

Results

TGFB1_rs1800469 was found to be associated with eczema [odds ratio (OR), 0.82; 95% confidence interval (CI): 0.73-0.92; P=0.001], atopic eczema (OR, 0.83; 95% CI: 0.72-0.95; P=0.009) and allergic rhinitis (OR, 0.84; 95% CI: 0.74-0.95; P=0.005). We also found a trend between IL10_rs1800872 and increased total immunoglobulin E (IgE) levels (P=0.009). Epistatic interaction among IL10_rs3021094, TGFB1_rs1800469, IL6R_rs2228145, and STAT3_rs4796793 were found for total IgE [testing accuracy (TA), 0.551; cross-validation consistency (CVC), 10; P=0.014]. Mean log-transformed total IgE (logIgE) levels in high-risk cases, low-risk cases, high-risk controls, and low-risk controls were 2.75, 2.60, 1.90, and 1.81 respectively (P=0.019 for trend).

Conclusions

Functional TGFB1 polymorphism is associated with both eczema and allergic rhinitis, suggesting the role of TGF-β1 in allergy susceptibility. IL10 may be associated with increased total IgE levels. Interaction among immune regulatory genes modulates total IgE levels.

Human germline gain-of-function in STAT6: from severe allergic disease to lymphoma and beyond

Signal transducer and activator of transcription (STAT)-6 is a transcription factor central to pro-allergic immune responses, although the function of human STAT6 at the whole-organism level has long remained unknown. Germline heterozygous gain-of-function (GOF) rare variants in STAT6 have been recently recognized to cause a broad and severe clinical phenotype of early-onset, multi-system allergic disease. Here, we provide an overview of the clinical presentation of STAT6-GOF disease, discussing how dysregulation of the STAT6 pathway causes severe allergic disease, and identifying possible targeted treatment approaches. Finally, we explore the mechanistic overlap between STAT6-GOF disease and other monogenic atopic disorders, and how this group of inborn errors of immunity (IEIs) powerfully inform our fundamental understanding of common human allergic disease.

TGFβ prevents IgE-mediated allergic disease by restraining T follicular helper 2 differentiation

Allergic diseases are common, affecting more than 20% of the population. Genetic variants in the TGFβ pathway are strongly associated with atopy. To interrogate the mechanisms underlying this association, we examined patients and mice with Loeys-Dietz syndrome (LDS) who harbor missense mutations in the kinase domain of TGFΒR1/2. We demonstrate that LDS mutations lead to reduced TGFβ signaling and elevated total and allergen-specific IgE, despite the presence of wild-type T regulatory cells in a chimera model. Germinal center activity was enhanced in LDS and characterized by a selective increase in type 2 follicular helper T cells (TFH2). Expression of Pik3cg was increased in LDS TFH cells and associated with reduced levels of the transcriptional repressor SnoN. PI3Kγ/mTOR signaling in LDS naïve CD4+ T cells was elevated after T cell receptor cross-linking, and pharmacologic inhibition of PI3Kγ or mTOR prevented exaggerated TFH2 and antigen-specific IgE responses after oral antigen exposure in an adoptive transfer model. Naïve CD4+ T cells from nonsyndromic allergic individuals also displayed decreased TGFβ signaling, suggesting that our mechanistic discoveries may be broadly relevant to allergic patients in general. Thus, TGFβ plays a conserved, T cell-intrinsic, and nonredundant role in restraining TFH2 development via the PI3Kγ/mTOR pathway and thereby protects against allergic disease.

ERBIN and phosphoglucomutase 3 deficiency

ERBIN and phosphoglucomutase 3 (PGM3) mutations both lead to rare primary atopic disorders characterized by allergic disease and connective tissue abnormalities, though each disorder has its own rather unique pattern of multisystem presentations. Pathway studies show how ERBIN mutations allow for enhanced TGFb signaling, and prevent STAT3 from negative-regulating TGFb signaling. This likely explains many elements of clinical overlap between disorders of STAT3 and TGFb signaling. The excessive TGFb signaling leading to increased IL-4 receptor expression also provides the rationale for precision-based therapy blocking the IL-4 receptor to treat the atopic disease. The mechanism by which PGM3 deficiency leads to atopic phenotypes is not well understood, nor is the broad variability in disease penetrance and expressivity, though preliminary studies suggest an overlap with IL-6 receptor signaling defects.

Sensing of protease activity as a triggering mechanism of Th2 cell immunity and allergic disease

CD4 T-helper cell type 2 (Th2) cells mediate host defense against extracellular parasites, like helminths. However, Th2 cells also play a pivotal role in the onset and progression of allergic inflammatory diseases such as atopic dermatitis, allergic rhinitis, asthma, and food allergy. This happens when allergens, which are otherwise harmless foreign proteins, are mistakenly identified as "pathogenic." Consequently, the encounter with these allergens triggers the activation of specific Th2 cell responses, leading to the development of allergic reactions. Understanding the molecular basis of allergen sensing is vital for comprehending how Th2 cell responses are erroneously initiated in individuals with allergies. The presence of protease activity in allergens, such as house dust mites (HDM), pollen, fungi, or cockroaches, has been found to play a significant role in triggering robust Th2 cell responses. In this review, we aim to examine the significance of protease activity sensing in foreign proteins for the initiation of Th2 cell responses, highlighting how evolving a host protease sensor may contribute to detect invading helminth parasites, but conversely can also trigger unwanted reactions to protease allergens. In this context, we will explore the recognition receptors activated by proteolytic enzymes present in major allergens and their contribution to Th2-mediated allergic responses. Furthermore, we will discuss the coordinated efforts of sensory neurons and epithelial cells in detecting protease allergens, the subsequent activation of intermediary cells, including mast cells and type 2 innate lymphoid cells (ILC2s), and the ultimate integration of all signals by conventional dendritic cells (cDCs), leading to the induction of Th2 cell responses. On the other hand, the review highlights the role of monocytes in the context of protease allergen exposure and their interaction with cDCs to mitigate undesirable Th2 cell reactions. This review aims to provide insights into the innate functions and cell communications triggered by protease allergens, which can contribute to the initiation of detrimental Th2 cell responses, but also promote mechanisms to effectively suppress their development.

LPS binding protein and activation signatures are upregulated during asthma exacerbations in children

Asthma exacerbations in children are associated with respiratory viral infection and atopy, resulting in systemic immune activation and infiltration of immune cells into the airways. The gene networks driving the immune activation and subsequent migration of immune cells into the airways remains incompletely understood. Cellular and molecular profiling of PBMC was employed on paired samples obtained from atopic asthmatic children (n = 19) during acute virus-associated exacerbations and later during convalescence. Systems level analyses were employed to identify coexpression networks and infer the drivers of these networks, and validation was subsequently obtained via independent samples from asthmatic children. During exacerbations, PBMC exhibited significant changes in immune cell abundance and upregulation of complex interlinked networks of coexpressed genes. These were associated with priming of innate immunity, inflammatory and remodelling functions. We identified activation signatures downstream of bacterial LPS, glucocorticoids and TGFB1. We also confirmed that LPS binding protein was upregulated at the protein-level in plasma. Multiple gene networks known to be involved positively or negatively in asthma pathogenesis, are upregulated in circulating PBMC during acute exacerbations, supporting the hypothesis that systemic pre-programming of potentially pathogenic as well as protective functions of circulating immune cells preceeds migration into the airways. Enhanced sensitivity to LPS is likely to modulate the severity of acute asthma exacerbations through exposure to environmental LPS.

Progesterone attenuates Th17-cell pathogenicity in autoimmune uveitis via Id2/Pim1 axis

BACKGROUND

Autoimmune uveitis (AU) is the most common ophthalmic autoimmune disease (AD) and is characterized by a complex etiology, high morbidity, and high rate of blindness. AU remission has been observed in pregnant female patients. However, the effects of progesterone (PRG), a critical hormone for reproduction, on the treatment of AU and the regulatory mechanisms remain unclear.

METHODS

To this end, we established experimental autoimmune uveitis (EAU) animal models and constructed a high-dimensional immune atlas of EAU-model mice undergoing PRG treatment to explore the underlying therapeutic mechanisms of PRG using single-cell RNA sequencing.

RESULTS

We found that PRG ameliorated retinal lesions and inflammatory infiltration in EAU-model mice. Further single-cell analysis indicated that PRG reversed the EAU-induced expression of inflammatory genes (AP-1 family, S100a family, and Cxcr4) and pathological processes related to inflammatory cell migration, activation, and differentiation. Notably, PRG was found to regulate the Th17/Treg imbalance by increasing the reduced regulatory functional mediators of Tregs and diminishing the overactivation of pathological Th17 cells. Moreover, the Id2/Pim1 axis, IL-23/Th17/GM-CSF signaling, and enhanced Th17 pathogenicity during EAU were reversed by PRG treatment, resulting in the alleviation of EAU inflammation and treatment of AD.

CONCLUSIONS

Our study provides a comprehensive single-cell map of the immunomodulatory effects of PRG therapy on EAU and elaborates on the possible therapeutic mechanisms, providing novel insights into its application for treating autoimmune diseases.

A model of Th2 differentiation based on polarizing cytokine repression

Conventional dendritic cells (cDCs) can integrate multiple stimuli from the environment and provide three separate outputs in terms of antigen presentation, costimulation, and cytokine production; this guides the activation, expansion, and differentiation of distinct functional T helper subsets. Accordingly, the current dogma posits that T helper cell specification requires these three signals in sequence. Data show that T helper 2 (Th2) cell differentiation requires antigen presentation and costimulation from cDCs but does not require polarizing cytokines. In this opinion article, we propose that the 'third signal' driving Th2 cell responses is, in fact, the absence of polarizing cytokines; indeed, the secretion of the latter is actively suppressed in cDCs, concomitant with acquired pro-Th2 functions.

Genetic and Molecular Contributors in Eosinophilic Esophagitis

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is an allergic inflammatory esophageal disorder with a complex underlying genetic and molecular etiology. The interest of the scientific community in EoE has grown considerably over the past three decades, and the understanding of the genetic and molecular mechanisms involved in this disease has greatly increased.

RECENT FINDINGS

In this article, we aim to provide both historic aspects and updates on the recent genetic and molecular advances in the understanding of EoE. Although EoE is a relatively newly described disorder, much progress has been made toward identifying the genetic and molecular factors contributing to the disease pathogenesis by a variety of approaches with next-generation sequencing technologies, including genome-wide association study, whole exome sequencing, and bulk and single-cell RNA sequencing. This review highlights the multifaceted impacts of various findings that have shaped the current molecular and genetic landscape of EoE, providing insights that facilitate further understanding of the disease process.

Proinflammatory plasticity towards Th17 paradigm of regulatory T cells consistent with elevated prevalence of TGFBR2 variants in elderly patients with primary immune thrombocytopenia

BACKGROUND

Primary immune thrombocytopenia (ITP) is characterized for the skewed Th differentiation towards Th1 and Th17 cells as well as the impaired number and function of regulatory T cells (Tregs). Tregs are capable of co-expressing effector Th markers in different inflammatory milieu, which probably indicates Treg dysfunction and incompetence to counter over-activated immune responses.

METHODS

Ninety-two primary ITP patients from March 2013 to December 2018 were included, and proinflammatory plasticity in different Treg compartments, age groups, and TGFBR2 variant carrier status were investigated.

RESULTS

Patients were categorized into elderly (n = 44) and younger (n = 48) groups according to an age of 50 years at disease onset. The overall remission rate was 82.6% after first-line regimens, including 47.8% complete remission. TGFBR2 variants were found in 7 (7.6%) patients with three V216I and four T340M heterozygote carriers. ITP patients demonstrated elevated co-expression of IL-17 and decreased co-expression of both IFN-γ and IL-13 than health control (all p < 0.01). The elderly group demonstrated elevated prevalence of TGFBR2 variants (p = 0.037) and elevated co-expression of IL-17 (p = 0.017) in Tregs, while female predominance was found in the younger group (p = 0.037). In the elderly group, TGFBR2 variant carriers demonstrated further elevated co-expression of IL-17 (p = 0.023) and decreased co-expression of both IFN-γ (p = 0.039) and IL-13 (p = 0.046) in the aTreg compartment.

CONCLUSIONS

Our findings revealed additional aberrations of Treg proinflammatory plasticity in elderly primary ITP patients, and highlighted the potential role of Treg dysfunction and senescence in the pathogenesis and management among these patients.

T-helper-2 cells and atopic disease: lessons learnt from inborn errors of immunity

Inborn errors of immunity (IEI) are caused by monogenic variants that affect the host response to bacterial, viral, and fungal pathogens. As such, individuals with IEI often present with severe, recurrent, and life-threatening infections. However, the spectrum of disease due to IEI is very broad and extends to include autoimmunity, malignancy, and atopic diseases such as eczema, atopic dermatitis, and food and environmental allergies. Here, I review IEI that affect cytokine signaling pathways that dysregulate CD4⁺ T-cell differentiation, resulting in increased T-helper-2 (Th2) cell development, function, and pathogenicity. These are elegant examples of how rare IEI can provide unique insights into more common pathologies such as allergic disease that are impacting the general population at increased frequency.

Cytokine-mediated STAT-dependent pathways underpinning human B-cell differentiation and function

B cells are fundamental to host defence against infectious diseases; indeed, the ability of humans to elicit robust antibody responses following exposure to foreign antigens underpins long-lived humoral immunity and serological memory, as well as the success of most currently administered vaccines. However, B cells also have a dark side - they can cause myriad diseases, including autoimmunity, atopy, allergy and malignancy. Thus, it is critical to understand the molecular requirements for generating effective, high-affinity, specific immune responses following natural infection or vaccination, as well as for constraining B-cell function to mitigate B-cell-mediated immune dyscrasias. In this review, we discuss recent developments that have been derived from the identification and detailed analysis of individuals with inborn errors of immunity that disrupt cytokine signalling, resulting in immune dysregulatory conditions. These studies have defined fundamental cytokine/cytokine receptor/signal transducer and activator of transcription (STAT) signalling pathways that are critical for the generation and maintenance of human memory B-cell and plasma cell subsets during host defence, as well as revealed mechanisms of disease pathogenesis causing immune deficiency, autoimmunity and atopy. More importantly, these studies have identified molecules that could be targeted to either enhance humoral immunity in the settings of infection or vaccination, or attenuate humoral immunity that contributes to antibody-mediated autoimmunity or allergy.

Retinal detachment in Loeys-Dietz syndrome

Loeys-Dietz syndrome (LDS) is an autosomal-dominant connective-tissue disorder with vascular and musculoskeletal abnormalities similar to Marfan syndrome. However, unlike Marfan, retinal detachment (RD) is rarely reported, and screening protocols do not currently feature ophthalmic assessment or RD counseling. We report a 5-generation family affected by LDS, where RD occurred in six eyes of four individuals. The proband was an 84-year-old male recently diagnosed with type-V LDS (TGFβ3 pathogenic variant c.899G>A, p.(Arg300Gln)). Further investigation was undertaken into the family's medical history. The proband experienced bilateral rhegmatogenous RD at age 60, requiring emergency surgical repair. Other notable ophthalmic features include unusual keratometry, abnormal biometry, and severe hayfever requiring long-term sodium cromoglycate treatment. The proband's sister, father, and uncle had also experienced RDs, all prior to LDS diagnosis. This series demonstrates that RD risk may be significant in LDS, and on occasion the presenting clinical feature. We suggest ophthalmic examination should be added to the initial assessment LDS patients, and patients informed of the early warning symptoms of retinal detachment. As in Marfan syndrome, LDS patients may exhibit cornea plana and abnormal corneal topography, producing atypical biometry. They may also present with allergic conjunctivitis, and awareness of these signs might facilitate earlier diagnosis.

Possible microRNA-based mechanism underlying relationship between chronic spontaneous urticaria and Blastocystis

BACKGROUND

Blastocystis spp. has been proposed as a possible cause of extraintestinal clinical signs such as urticaria pathogenesis.

OBJECTIVES

The aim of this study was to investigate the differences between microRNA (miRNA) expression profiles of Chronic spontaneous urticaria (CSU) patients in the presence or absence of Blastocystis spp. as well as healthy controls. Additionally, cellular pathways which are affected in the presence of Blastocystis spp. were identified.

METHODS

Twenty patients diagnosed with CSU were enrolled in the study and divided into equally two groups according to the presence of Blastocystis spp. Besides, six healthy individuals were included in the study. The expression profiles of 372 human-derived miRNAs have been investigated in serum samples from CSU patients and healthy controls with miScript miRNA PCR Array Human miRBase Profiler.

RESULTS

Compared to Blastocystis-negative (BN)-CSU patients, expression of 3 miRNAs (hsa-miR-3183, hsa-miR-4469, hsa-miR-5191) were found to be downregulated by at least two-fold (p < 0.05) in Blastocystis-positive (BP)-CSU patients. Additionally, the miRNA expression profiles of six healthy individuals (n = 3 Blastocystis-positive, n = 3 Blastocystis-negative) were analyzed and it was determined that the expressions of 7 miRNAs (hsa-miR-4661-5p, hsa-miR-4666a-5p, hsa-miR-4803, hsa-miR-5587-5p, hsa-miR-4500, hsa-miR-5680, hsa-miR-382-3p) increased at least 3-fold in the serum of individuals with Blastocystis-positive compared to Blastocystis-negative subjects. Most down-regulated miRNAs, in BP-CSU patients, affect cell adhesion molecules (CAMs), and signaling pathways therefore, Blastocystis spp. presence may influence the clinical presentation of urticaria by leading to unbalanced immunity. In addition, Blastocystis spp. presence may be influenced TGF- β signaling pathway through altered miRNAs and may be laying the groundwork for the development of CSU in healthy individuals.

CONCLUSIONS

As a consequence, this is the first report to show that the miRNA expression profile is affected by the presence of Blastocystis spp. Further miRNA-based studies are needed in order to enlighten the exact underlying molecular mechanisms of the relationship between Blastocystis spp. and CSU.

Epithelial-intrinsic defects in TGFβR signaling drive local allergic inflammation manifesting as eosinophilic esophagitis

Allergic diseases are a global health challenge. Individuals harboring loss-of-function variants in transforming growth factor-β receptor (TGFβR) genes have an increased prevalence of allergic disorders, including eosinophilic esophagitis. Allergic diseases typically localize to mucosal barriers, implicating epithelial dysfunction as a cardinal feature of allergic disease. Here, we describe an essential role for TGFβ in the control of tissue-specific immune homeostasis that provides mechanistic insight into these clinical associations. Mice expressing a TGFβR1 loss-of-function variant identified in atopic patients spontaneously develop disease that clinically, immunologically, histologically, and transcriptionally recapitulates eosinophilic esophagitis. In vivo and in vitro, TGFβR1 variant-expressing epithelial cells are hyperproliferative, fail to differentiate properly, and overexpress innate proinflammatory mediators, which persist in the absence of lymphocytes or external allergens. Together, our results support the concept that TGFβ plays a fundamental, nonredundant, epithelial cell-intrinsic role in controlling tissue-specific allergic inflammation that is independent of its role in adaptive immunity.

Tailored treatments in inborn errors of immunity associated with atopy (IEIs-A) with skin involvement

Inborn errors of immunity associated with atopy (IEIs-A) are a group of inherited monogenic disorders that occur with immune dysregulation and frequent skin involvement. Several pathways are involved in the pathogenesis of these conditions, including immune system defects, alterations of skin barrier and metabolism perturbations. Current technological improvements and the higher accessibility to genetic testing, recently allowed the identification of novel molecular pathways involved in IEIs-A, also informing on potential tailored therapeutic strategies. Compared to other systemic therapy for skin diseases, biologics have the less toxic and the best tolerated profile in the setting of immune dysregulation. Here, we review IEIs-A with skin involvement focusing on the tailored therapeutic approach according to their pathogenetic mechanism.

Dysregulation of the immune response in TGF-β signalopathies

The transforming growth factor-β (TGF-β) family of cytokines exerts pleiotropic functions during embryonic development, tissue homeostasis and repair as well as within the immune system. Single gene defects in individual component of this signaling machinery cause defined Mendelian diseases associated with aberrant activation of TGF-β signaling, ultimately leading to impaired development, immune responses or both. Gene defects that affect members of the TGF-β cytokine family result in more restricted phenotypes, while those affecting downstream components of the signaling machinery induce broader defects. These rare disorders, also known as TGF-β signalopathies, provide the unique opportunity to improve our understanding of the role and the relevance of the TGF-β signaling in the human immune system. Here, we summarize this elaborate signaling pathway, review the diverse clinical presentations and immunological phenotypes observed in these patients and discuss the phenotypic overlap between humans and mice genetically deficient for individual components of the TGF-β signaling cascade.

Genetic diagnosis for adult patients at a genetic clinic

Clinical utility of genetic testing has rapidly increased in the past decade to identify the definitive diagnosis, etiology, and specific management. The majority of patients receiving testing are children. There are several barriers for genetic tests in adult patients; barriers may arise from either patients or clinicians. Our study aims to realize the detection rate and the benefits of genetic tests in adults. We conducted a prospective study of 10 adult patients who were referred to a genetic clinic. Exome sequencing (ES) was pursued in all cases, and chromosomal microarray (CMA) was performed for six cases. Our result is impressive; six cases (60%) received likely pathogenic and pathogenic variants. Four definitive diagnosis cases had known pathogenic variants in KCNJ2, TGFBR1, SCN1A, and FBN1, whereas another two cases revealed novel likely pathogenic and pathogenic variants in GNB1 and DNAH9. Our study demonstrates the success in genetic diagnosis in adult patients: four cases with definitive, two cases with possible, and one case with partial diagnosis. The advantage of diagnosis is beyond obtaining the diagnosis itself, but also relieving any doubt for the patient regarding any previous questionable diagnosis, guide for management, and recurrence risk in their children or family members. Therefore, this supports the value of genetic testing in adult patients.

Infant with Loeys-Dietz syndrome treated for febrile status epilepticus with COVID-19 infection: first reported case of febrile status epilepticus and focal seizures in a patient with Loeys-Dietz syndrome and review of literature

Loeys-Dietz syndrome (LDS) is a rare, autosomal dominant multisystem disorder that is caused by mutations of transforming growth factor-β receptors. Mutations inSMAD3andTGFB3have been recently reported.

LDS is characterised by the triad of arterial tortuosity, hypertelorism and a bifid uvula or cleft palate among other cardiovascular, craniofacial and orthopaedic manifestations. Patients with LDS show clinical and genetic variability and there is a significant risk of reduced life expectancy due to widespread arterial involvement, aortic root dilation, aneurysms and an aggressive vascular course. Thus early genetic testing is warranted if clinical signs and history are suggestive of this potentially catastrophic disorder.

LDS predisposes patients to aortic aneurysms and early death due to vascular malformations, but neurological emergencies, such as seizures and febrile status epilepticus, have not been reported.

Febrile status epilepticus is the most common neurological emergency in childhood. Neurological manifestations of COVID-19 in the paediatric population are not as well described in medical literature.

To the best of our knowledge, this is the first reported case of febrile status epilepticus with COVID-19 infection in an infant with LDS. Our patient had focal epileptiform activity emanating over the left posterior hemisphere, which evolved into an electrographic seizure on video EEG. Such patients have a heightened risk of epilepsy in the future, and this occurrence is consistent with a diagnosis of focal epilepsy. Neurological complications such as epilepsy and status epilepticus in a patient with LDS have never been reported before.

A brief review of literature is also given here.

Clinical features and complications of Loeys-Dietz syndrome: A systematic review

INTRODUCTION

Loeys-Dietz syndrome (LDS) is a connective tissue disorder that arises from mutations altering the transforming growth factor β signalling pathway. Due to the recent discovery of the underlying genetic mutations leading to LDS, the spectrum of characteristics and complications is not fully understood.

METHODS

Our search included five databases (Pubmed, SCOPUS, Web of Science, EMBASE and google scholar) and included variations of "Loeys-Dietz Syndrome" as search terms, using all available data until February 2021. All study types were included. Three reviewers screened 1394 abstracts, of which 418 underwent full-text review and 392 were included in the final analysis.

RESULTS

We identified 3896 reported cases of LDS with the most commonly reported features and complications being: aortic aneurysms and dissections, arterial tortuosity, high arched palate, abnormal uvula and hypertelorism. LDS Types 1 and 2 share many clinical features, LDS Type 2 appears to have a more aggressive aortic disease. LDS Type 3 demonstrated an increased prevalence of mitral valve prolapse and arthritis. LDS Type 4 and 5 demonstrated a lower prevalence of musculoskeletal and cardiovascular involvement. Amongst 222 women who underwent 522 pregnancies, 4% experienced an aortic dissection and the peripartum mortality rate was 1%.

CONCLUSION

We observed that LDS is a multisystem connective tissue disorder that is associated with a high burden of complications, requiring a multidisciplinary approach. Ongoing attempts to better characterise these features will allow clinicians to appropriately screen and manage these complications.

Cleft Palate and Aortic Dilatation as Clues for Loeys-Dietz Syndrome

Loeys-Dietz syndrome (LDS) is a rare autosomal-dominant disorder of the connective tissue with some typical vascular findings, skeletal manifestations, craniofacial features, and cutaneous findings with a wide phenotypic spectrum. Six different genes are involved in LDS and the diagnosis is based on the identification of a heterozygous pathogenic variant in TGFBR1, TGFBR2, SMAD3, TGFB2, TGFB3, or SMAD2 in children with suggestive findings. These genes distinguish LDS into six classes (LDS1-LDS6, respectively). Delay in diagnosis of Loeys-Dietz syndrome may be associated with an adverse prognosis due to a very high augmented risk of early complications such as aortic or vascular rupture. The present report describes a case of an early diagnosis of LDS in a neonate with cleft soft palate and aortic root dilatation.

Inborn Errors of Immunity Associated with Elevated IgE

OBJECTIVE

To review the characteristic clinical and laboratory features of inborn errors of immunity that are associated with elevated IgE levels DATA SOURCE: Primary peer-reviewed literature.

STUDY SELECTION

Original research articles reviewed include interventional studies, retrospective studies, case-control studies, cohort studies and review articles related to the subject matter.

RESULTS

An extensive literature review was completed to allow for comprehensive evaluation of several monogenic inborn errors of immunity. This review includes a description of the classic clinical features, common infections, characteristic laboratory findings, specific diagnostic methods (when applicable), and genetic basis of disease of each syndrome. A comprehensive flow diagram was created to assist them in the diagnosis and evaluation of patients with elevated IgE levels who may require evaluation for an IEI.

CONCLUSION

IEI should be considered in patients with elevated IgE levels, especially if they have recurrent infections, eczematous dermatitis, malignancy, lymphoproliferation, autoimmunity, and/or connective tissue abnormalities.

Atopy as Immune Dysregulation: Offender Genes and Targets

Allergic diseases are a heterogeneous group of disorders resulting from exaggerated type 2 inflammation. Although typically viewed as polygenic multifactorial disorders caused by the interaction of several genes with the environment, we have come to appreciate that allergic diseases can also be caused by monogenic variants affecting the immune system and the skin epithelial barrier. Through a myriad of genetic association studies and high-throughput sequencing tools, many monogenic and polygenic culprits of allergic diseases have been described. Identifying the genetic causes of atopy has shaped our understanding of how these conditions occur and how they may be treated and even prevented. Precision diagnostic tools and therapies that address the specific molecular pathways implicated in allergic inflammation provide exciting opportunities to improve our care for patients across the field of allergy and immunology. Here, we highlight offender genes implicated in polygenic and monogenic allergic diseases and list targeted therapeutic approaches that address these disrupted pathways.

Lung Epithelial CYP1 Activity Regulates Aryl Hydrocarbon Receptor Dependent Allergic Airway Inflammation

The lung epithelial barrier serves as a guardian towards environmental insults and responds to allergen encounter with a cascade of immune reactions that can possibly lead to inflammation. Whether the environmental sensor aryl hydrocarbon receptor (AhR) together with its downstream targets cytochrome P450 (CYP1) family members contribute to the regulation of allergic airway inflammation remains unexplored. By employing knockout mice for AhR and for single CYP1 family members, we found that AhR^-/- and CYP1B1^-/- but not CYP1A1^-/- or CYP1A2^-/- animals display enhanced allergic airway inflammation compared to WT. Expression analysis, immunofluorescence staining of murine and human lung sections and bone marrow chimeras suggest an important role of CYP1B1 in non-hematopoietic lung epithelial cells to prevent exacerbation of allergic airway inflammation. Transcriptional analysis of murine and human lung epithelial cells indicates a functional link of AhR to barrier protection/inflammatory mediator signaling upon allergen challenge. In contrast, CYP1B1 deficiency leads to enhanced expression and activity of CYP1A1 in lung epithelial cells and to an increased availability of the AhR ligand kynurenic acid following allergen challenge. Thus, differential CYP1 family member expression and signaling via the AhR in epithelial cells represents an immunoregulatory layer protecting the lung from exacerbation of allergic airway inflammation.

Eosinophilia Associated With Immune Deficiency

The differential diagnosis of eosinophilia is broad and includes infections, malignancies, and atopy as well as inborn errors of immunity (IEI). Certain types of IEIs are known to be associated with elevated numbers of eosinophils and frequently elevated serum IgE, whereas for others the degree and frequency of eosinophilia are less established. The molecular defects underlying IEI are heterogeneous and affect different pathways, which highlights the complex regulations of this cell population within the immune system. In this review, we list and discuss clinical manifestations and therapies of immune deficiency or immune dysregulation disorders associated with peripheral blood or tissue eosinophilia with or without raised IgE levels. We present illustrative case vignettes for the most common entities and propose a diagnostic algorithm aiming to help physicians systematically to evaluate patients with eosinophilia and suspicion of an underlying IEI.

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.

Evolution and long-term outcomes of combined immunodeficiency due to CARMIL2 deficiency

BACKGROUND

Biallelic loss-of-function mutations in CARMIL2 cause combined immunodeficiency associated with dermatitis, inflammatory bowel disease (IBD), and EBV-related smooth muscle tumors. Clinical and immunological characterizations of the disease with long-term follow-up and treatment options have not been previously reported in large cohorts. We sought to determine the clinical and immunological features of CARMIL2 deficiency and long-term efficacy of treatment in controlling different disease manifestations.

METHODS

The presenting phenotypes, long-term outcomes, and treatment responses were evaluated prospectively in 15 CARMIL2-deficient patients, including 13 novel cases. Lymphocyte subpopulations, protein expression, regulatory T (Treg), and circulating T follicular helper (cT_FH ) cells were analyzed. Three-dimensional (3D) migration assay was performed to determine T-cell shape.

RESULTS

Mean age at disease onset was 38 ± 23 months. Main clinical features were skin manifestations (n = 14, 93%), failure to thrive (n = 10, 67%), recurrent infections (n = 10, 67%), allergic symptoms (n = 8, 53%), chronic diarrhea (n = 4, 27%), and EBV-related leiomyoma (n = 2, 13%). Skin manifestations ranged from atopic and seborrheic dermatitis to psoriasiform rash. Patients had reduced proportions of memory CD4⁺ T cells, Treg, and cT_FH cells. Memory B and NK cells were also decreased. CARMIL2-deficient T cells exhibited reduced T-cell proliferation and cytokine production following CD28 co-stimulation and normal morphology when migrating in a high-density 3D collagen gel matrix. IBD was the most severe clinical manifestation, leading to growth retardation, requiring multiple interventional treatments. All patients were alive with a median follow-up of 10.8 years (range: 3-17 years).

CONCLUSION

This cohort provides clinical and immunological features and long-term follow-up of different manifestations of CARMIL2 deficiency.

A novel nonsense mutation of TGFBR1 in a fetus with untypical Loeys-Dietz syndrome 1

OBJECTIVE

We present a rare untypical Loeys-Dietz syndrome 1 case in prenatal setting and report a novel mutation in the TGFBR1 gene.

CASE REPORT

A pregnant woman came for medical attention due to the fetal ultrasound anomaly. The fetus was found to have short long bones. Trio-based WES was applied to the family. A novel de novo nonsense mutation c.1237C > T was detected in the TGFBR1 gene. A diagnosis of Loeys-Dietz syndrome 1 (LDS1) was plausible, but the fetus did not demonstrate the characteristic phenotype of the syndrome.

CONCLUSION

In prenatal setting, fetal phenotypes are difficult to be fully observed, putting stress on the utility of molecular techniques. LDS1 in fetuses could present untypical features such as skeletal dysplasia.

Predictors of low bone density and fracture risk in Loeys-Dietz syndrome

PURPOSE

Loeys-Dietz syndrome (LDS) is a connective tissue disorder affecting multiple organ systems, including bone.

METHODS

We defined the bone phenotype and clinical predictors of low bone density and fracture risk in 77 patients with LDS type 1 to type 5.

RESULTS

Patients with LDS had dual-energy x-ray absorptiometry (DXA) Z-scores significantly < 0, and 50% of children and 9% of adults had Z-scores < -2. Sixty percent of patients had ≥1 fracture, and 24% of patients with spinal x-rays scans showed spinal compression fractures. Lower body mass index, asthma, male sex and eosinophilic gastrointestinal disease were correlated with lower DXA Z-scores. The count of 5 LDS-associated skeletal features (scoliosis, pes planus, arachnodactyly, spondylolisthesis, and camptodactyly) in patients with LDS was correlated with DXA Z-score. Adults with ≥1 skeletal features had DXA Z-scores significantly < 0, and children with >2 features had DXA Z-score significantly < -2. Bone turnover markers suggest accelerated bone resorption. Data from 5 patients treated with bisphosphonates suggest a beneficial effect.

CONCLUSION

All LDS types are associated with reduced bone density and increased risk of fracture, which may be due to increased bone resorption. Clinical features can predict a subgroup of patients at highest risk of low bone density and fracture risk.

Therapeutic Approach of Very Early-Onset Inflammatory Bowel Disease in a Loeys-Dietz Syndrome Child

Heterozygous TGFBR2 loss-of-function mutation is an extremely rare cause of very-early onset inflammatory bowel disease (VEOIBD) as, so far, only three cases have been reported in the literature. VEOIBD therapeutic management remains a real challenge for clinicians. Here, we described an interesting new case of Loeys-Dietz syndrome presenting severe, very early intestinal inflammation associated with dysmorphic features, aortic arch tortuosity joint hyper laxity and severe scoliosis. TGFBR2 Sanger sequencing revealed a missense mutation c.1583G>A (p.Arg528His). As endoscopy confirmed a severe colitis, we chose a classical IBD therapeutic approach. We finally obtained remission under Ustekinumab (90 mg/6 weeks).

Type 2 Inflammation in Eosinophilic Esophagitis: From Pathophysiology to Therapeutic Targets

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease of the esophagus characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation, whose incidence is rising. It significantly affects patients’ quality of life and, if left untreated, results in fibrotic complications. Although broad consensus has been achieved on first-line therapy, a subset of patients remains non-responder to standard therapy. The pathogenesis of EoE is multifactorial and results from the complex, still mostly undefined, interaction between genetics and intrinsic factors, environment, and antigenic stimuli. A deep understanding of the pathophysiology of this disease is pivotal for the development of new therapies. This review provides a comprehensive description of the pathophysiology of EoE, starting from major pathogenic mechanisms (genetics, type 2 inflammation, epithelial barrier dysfunction, gastroesophageal reflux, allergens, infections and microbiota) and subsequently focusing on the single protagonists of type 2 inflammation (involved cells, cytokines, soluble effectors, surface proteins and transcription factors) that could represent present and future therapeutic targets, while summarizing previous therapeutic approaches in literature.

Role of airway smooth muscle cell phenotypes in airway tone and obstruction in guinea pig asthma model

Background

Airway obstruction (AO) in asthma is driven by airway smooth muscle (ASM) contraction. AO can be induced extrinsically by direct stimulation of ASM with contractile agonists as histamine, or by indirect provocation with antigens as ovalbumin, while the airway tone is dependent on intrinsic mechanisms. The association of the ASM phenotypes involved in different types of AO and airway tone in guinea pigs was evaluated.

Methods

Guinea pigs were sensitized to ovalbumin and challenged with antigen. In each challenge, the maximum OA response to ovalbumin was determined, and before the challenges, the tone of the airways. At third challenge, airway responsiveness (AR) to histamine was evaluated and ASM cells from trachea were disaggregated to determinate: (a) by flow cytometry, the percentage of cells that express transforming growth factor-β1 (TGF-β1), interleukin-13 (IL-13) and sarco-endoplasmic Ca²⁺ ATPase-2b (SERCA2b), (b) by RT-PCR, the SERCA2B gene expression, (c) by ELISA, reduced glutathione (GSH) and, (d) Ca²⁺ sarcoplasmic reticulum refilling rate by microfluorometry. Control guinea pig group received saline instead ovalbumin.

Results

Antigenic challenges in sensitized guinea pigs induced indirect AO, AR to histamine and increment in airway tone at third challenge. No relationship was observed between AO induced by antigen and AR to histamine with changes in airway tone. The extent of antigen-induced AO was associated with both, TGF-β1 expression in ASM and AR degree. The magnitude of AR and antigen-induced AO showed an inverse correlation with GSH levels in ASM. The airway tone showed an inverse association with SERCA2b expression.

Conclusions

Our data suggest that each type of AO and airway tone depends on different ASM phenotypes: direct and indirect AO seems to be sensitive to the level of oxidative stress; indirect obstruction induced by antigen appears to be influenced by the expression of TGF-β1 and the SERCA2b expression level plays a role in the airway tone.

Respiratory manifestations of Marfan syndrome: a narrative review

Objective

The prevalence of Marfan syndrome (MFS) is estimated to be 1 in 10,000 to 15,000 individuals, but the phenotype of MFS may not be apparent and hence its diagnosis may not be considered by clinicians. Furthermore, the effects of MFS on the lungs and breathing are underrecognized despite the high morbidity that can occur. The objective of this Narrative Review is to delineate the molecular consequences of a defective fibrillin-1 protein and the skeletal and lung abnormalities in MFS that may contribute to respiratory compromise. It is important for clinicians to be cognizant of these MFS-associated respiratory conditions, and a contemporaneous review is needed.

Background

MFS is an autosomal dominant, connective tissue disorder caused by mutations in the FIBRILLIN-1 (FBN1) gene, resulting in abnormal elastic fibers as well as increased tissue availability of transforming growth factor-beta (TGFβ), both of which lead to the protean clinical abnormalities. While these clinical characteristics are most often recognized in the cardiovascular, skeletal, and ocular systems, MFS may also cause significant impairment on the lungs and breathing.

Methods

We searched PubMed for the key words of “Marfan syndrome,” “pectus excavatum,” and “scoliosis” with that of “lung disease,” “breathing”, or “respiratory disease.” The bibliographies of identified articles were further searched for relevant articles not previously identified. Each relevant article was reviewed by one or more of the authors and a narrative review was composed.

Conclusions

Though the classic manifestations of MFS are cardiovascular, skeletal, and ocular, FBN1 gene mutation can induce a variety of effects on the respiratory system, inducing substantial morbidity and potentially increased mortality. These respiratory effects may include chest wall and spinal deformities, emphysema, pneumothorax, sleep apnea, and potentially increased incidence of asthma, bronchiectasis, and interstitial lung disease. Further research into approaches to prevent respiratory complications is needed, but improved recognition of the respiratory complications of MFS is necessary before this research is likely to occur.

Intestinal immunoregulation: lessons from human mendelian diseases

The mechanisms that maintain intestinal homeostasis despite constant exposure of the gut surface to multiple environmental antigens and to billions of microbes have been scrutinized over the past 20 years with the goals to gain basic knowledge, but also to elucidate the pathogenesis of inflammatory bowel diseases (IBD) and to identify therapeutic targets for these severe diseases. Considerable insight has been obtained from studies based on gene inactivation in mice as well as from genome wide screens for genetic variants predisposing to human IBD. These studies are, however, not sufficient to delineate which pathways play key nonredundant role in the human intestinal barrier and to hierarchize their respective contribution. Here, we intend to illustrate how such insight can be derived from the study of human Mendelian diseases, in which severe intestinal pathology results from single gene defects that impair epithelial and or hematopoietic immune cell functions. We suggest that these diseases offer the unique opportunity to study in depth the pathogenic mechanisms leading to perturbation of intestinal homeostasis in humans. Furthermore, molecular dissection of monogenic intestinal diseases highlights key pathways that might be druggable and therapeutically targeted in common forms of IBD.

Toward precision medicine in vascular connective tissue disorders

Tremendous progress has been made in understanding the etiology, pathogenesis, and treatment of inherited vascular connective tissue disorders. While new insights regarding disease etiology and pathogenesis have informed patient counseling and care, there are numerous obstacles that need to be overcome in order to achieve the full promise of precision medicine. In this review, these issues will be discussed in the context of Marfan syndrome and Loeys-Dietz syndrome, with additional emphasis on the pioneering contributions made by Victor McKusick.

Cellular and molecular mechanisms of allergic asthma

Asthma is a chronic disease of the airways, which affects more than 350 million people worldwide. It is the most common chronic disease in children, affecting at least 30 million children and young adults in Europe. Asthma is a complex, partially heritable disease with a marked heterogeneity. Its development is influenced both by genetic and environmental factors. The most common, as well as the most well characterized subtype of asthma is allergic eosinophilic asthma, which is characterized by a type 2 airway inflammation. The prevalence of asthma has substantially increased in industrialized countries during the last 60 years. The mechanisms underpinning this phenomenon are incompletely understood, however increased exposure to various environmental pollutants probably plays a role. Disease inception is thought to be enabled by a disadvantageous shift in the balance between protective and harmful lifestyle and environmental factors, including exposure to protective commensal microbes versus infection with pathogens, collectively leading to airway epithelial cell damage and disrupted barrier integrity. Epithelial cell-derived cytokines are one of the main drivers of the type 2 immune response against innocuous allergens, ultimately leading to infiltration of lung tissue with type 2 T helper (T_H2) cells, type 2 innate lymphoid cells (ILC2s), M2 macrophages and eosinophils. This review outlines the mechanisms responsible for the orchestration of type 2 inflammation and summarizes the novel findings, including but not limited to dysregulated epithelial barrier integrity, alarmin release and innate lymphoid cell stimulation.

A unique esophageal extracellular matrix proteome alters normal fibroblast function in severe eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic TH2 disorder complicated by tissue fibrosis and loss of esophageal luminal patency. The fibrostenotic esophagus does not respond well to therapy, but profibrotic therapeutic targets are largely unclear.

OBJECTIVE

Our aim was to utilize proteomics and primary cells as a novel approach to determine relevant profibrotic factors.

METHODS

We utilized primary esophageal EoE and normal fibroblasts, their derivative extracellular matrixes (ECMs), an approach of fibroblast culture on autologous versus nonautologous ECM, and proteomics to elucidate EoE ECM proteins that dysregulate cellular function.

RESULTS

We cultured esophageal fibroblasts from normal esophagi and esophagi from patients with severe EoE on autologous versus nonautologous ECM. The EoE ECM proteome shifted normal esophageal fibroblast protein expression. Proteomic analysis demonstrated that thrombospondin-1 is detected only in the EoE ECM, is central in the EoE ECM protein-protein interactome, is found at significantly elevated levels in biopsy specimens from patients with active EoE, and induces fibroblast collagen I production.

CONCLUSION

Fibroblasts from patients with EoE secrete a unique ECM proteome that reflects their in vivo state and induces collagen I and α-smooth muscle actin protein expression from normal fibroblasts. Thrombospondin-1 is a previously unappreciated profibrotic molecule in EoE.

The role of impulse oscillometry in the management of asthma when forced expiratory maneuvers are contraindicated: case series and literature review

Objectives: The impulse oscillometry system (IOS) provides an alternative method of lung function testing for patients in whom forced expiratory manoeuvres are contraindicated, such as those with inherited vascular connective tissue disorders. Here we examine the role of IOS in the diagnosis and monitoring of asthma in such patients through a clinical case series and literature review.Methods: The clinical case series comprised of data from 12 patients with inherited connective tissue disorders representing 32 clinical encounters. Of these, 11 encounters were for asthma diagnosis and 21 were for asthma monitoring. Symptoms, exhaled nitric oxide (FeNO) and IOS were assessed at each encounter.Results: In the clinical case series, 5 of 6 patients with likely asthma (as determined by physician review and exhaled nitric oxide testing) had abnormal IOS parameters compared with 0 of 5 of those with unlikely asthma. In the monitoring group, 11 encounters resulted in treatment escalation (demonstrating suboptimal control), and 8 resulted in no change to treatment (good control). Six of 11 of those with suboptimal control had abnormalities in ≥3 IOS parameters, with R5 and R5-20 most frequently affected. Only 1 of 8 of those with good control had abnormalities in ≥3 IOS parameters.Conclusions: IOS can be used as an alternative to conventional lung function testing to support the diagnosis and monitoring of asthma when forced expiratory manoeuvres are contraindicated. Larger studies are required to establish severity and treatment escalation thresholds and provide clearer comparisons with spirometry values.