Persistent esophageal changes after histologic remission in eosinophilic esophagitis.

BACKGROUND: Eosinophilic esophagitis (EoE) is characterized by persistent or relapsing allergic inflammation, and both clinical and histologic features of esophageal inflammation persist over time in most individuals. Mechanisms contributing to EoE relapse are not understood, and chronic EoE-directed therapy is therefore required to prevent long-term sequelae. OBJECTIVE: We investigated whether EoE patients in histologic remission have persistent dysregulation of esophageal gene expression. METHODS: Esophageal biopsy samples from 51 pediatric and 52 adult subjects with EoE in histopathologic remission (<15 eosinophils per high-power field [eos/hpf]) and control (48 pediatric and 167 adult) subjects from multiple institutions were subjected to molecular profiling by the EoE diagnostic panel, which comprises a set of 94 esophageal transcripts differentially expressed in active EoE. RESULTS: Defining remission as <15 eos/hpf, we identified 51 and 32 differentially expressed genes in pediatric and adult EoE patients compared to control individuals, respectively (false discovery rate < 0.05). Using the stringent definition of remission (0 eos/hpf), the adult and pediatric cohorts continued to have 18 and 25 differentially expressed genes (false discovery rate < 0.05). Among 6 shared genes between adults and children, CDH26 was upregulated in both children and adults; immunohistochemistry demonstrated increased cadherin 26 staining in the epithelium of EoE patients in remission compared to non-EoE controls. In the adult cohort, POSTN expression correlated with the endoscopic reference system score (Spearman r = 0.35, P = .011), specifically correlating with the rings' endoscopic reference system subscore (r = 0.53, P = .004). CONCLUSION: We have identified persistent EoE-associated esophageal gene expression in patients with disease in deep remission. These data suggest potential inflammation-induced epigenetic mechanisms may influence gene expression during remission in EoE and provide insight into possible mechanisms that underlie relapse in EoE.

Advances and ongoing challenges in eosinophilic gastrointestinal disorders presented at the CEGIR/TIGERs Symposium at the 2024 American Academy of Allergy, Asthma & Immunology meeting.

The Consortium of Eosinophilic Gastrointestinal disease Researchers (CEGIR) and The International Gastrointestinal Eosinophil Researchers (TIGERs) organized a daylong symposium at the 2024 annual meeting of the American Academy of Allergy, Asthma & Immunology. The symposium featured new discoveries in basic and translational research as well as debates on the mechanisms and management of eosinophilic gastrointestinal diseases. Updates on recent clinical trials and consensus guidelines were also presented. We summarize the updates on eosinophilic gastrointestinal diseases presented at the symposium.

A patient with Pitt-Hopkins syndrome with concomitant common variable immunodeficiency.

In patients with 18q deletion syndrome (18q-), immunodeficiency, autoimmunity, and allergies have been described in a subset. Pitt-Hopkins syndrome represents a specific subset of patients with 18q- who have a proximal deletion involving the TCF4 gene or a TCF4 variant. Immunodeficiency has been reported in the overall 18q- population; however, immunodeficiency with Pitt-Hopkins syndrome has not been highlighted. This case report details the immunologic evaluations and the associated infections seen in a young adult with Pitt-Hopkins syndrome to underscore the challenges of managing adults with a complex phenotype who develop frequent infections. This patient with Pitt-Hopkins syndrome ultimately fulfilled the diagnostic criteria for common variable immunodeficiency. Immunoglobulin replacement has led to a somewhat improved infection pattern, although she continues to have aspiration events leading to pneumonia. This case highlights the clinical evolution of Pitt-Hopkins syndrome and serves as a reminder that immunodeficiency can occur in this syndrome.

Developmental and behavioral phenotypes of pediatric patients with PTEN hamartoma tumor syndrome.

Our study characterized the neurodevelopmental spectrum of individuals with PTEN Hamartoma Tumor Syndrome (PHTS), a syndrome that predisposes to both neurodevelopmental phenotypes and cancer risk. We aim to better understand life-impacting neurodevelopmental features of PHTS. Our study recruited 20 children/adolescents with PHTS, who were then administered assessments for autism spectrum disorder (ASD) and other neurocognitive measures, including assessment of IQ, executive and adaptive functioning, and health-related quality of life. Thirteen individuals (65%) were identified as having ASD, of which five were newly diagnosed during the study. Of those, ASD symptom severity was in the mild-moderate range for 77%. Overall, IQ was in the average range, with a mean of 92.61 (SD 24.45, p = 0.5), though there was a non-statistically significant trend toward individuals without ASD having a higher mean IQ (102.7 vs 82.3; p = 0.1). Subjects had significant impairment in processing speed (mean 75.38, SD 24.75, p < 0.05), decreased adaptive functioning skills across all domains, and a trend toward having more executive functioning problems. Individuals with PHTS are at increased risk of neurodevelopmental disorders, including ASD and impaired executive and adaptive functioning. Although clear guidelines exist for cancer surveillance for individuals with PHTS, additional guidelines and screening for neurodevelopmental disorders are warranted.

Current and future perspectives on the consensus guideline for food protein-induced enterocolitis syndrome (FPIES).

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE mediated food allergy presenting with delayed onset of projectile vomiting in the absence of cutaneous and respiratory symptoms. The pathophysiology of FPIES remains poorly characterized. The first international consensus guidelines for FPIES were published in 2017 and provided clinicians with parameters on the diagnosis and treatment of FPIES. The guidelines have served as a resource in the recognition and management of FPIES, contributing to an increased awareness of FPIES. Since then, new evidence has emerged, shedding light on adult-onset FPIES, the different phenotypes of FPIES, the recognition of new food triggers, center-specific food challenge protocols and management of acute FPIES. Emerging evidence indicates that FPIES impacts both pediatric and adult population. As a result, there is growing need to tailor the consensus guidelines to capture diagnoses in both patient groups. Furthermore, it is crucial to provide food challenge protocols that meet the needs of both pediatric and adult FPIES patients, as well as the subset of patients with atypical FPIES. This review highlights the evolving clinical evidence relating to FPIES diagnosis and management published since the 2017 International FPIES Guidelines. We will focus on areas where recent published evidence may support evolution or revision of the guidelines.

Conserved IFN Signature between Adult and Pediatric Eosinophilic Esophagitis.

Eosinophilic esophagitis (EoE) is an allergic inflammatory disease of the esophagus that occurs in both children and adults. Previous studies of affected tissue from pediatric cohorts have identified prominent signatures of eosinophilia and type 2 inflammation. However, the details of the immune response in adults with EoE are still being elucidated. To determine whether EoE in adults shares inflammatory profiles with those observed in children, we performed RNA sequencing of paired human esophageal biopsies and blood samples from adults with EoE or gastroesophageal reflux disease. Unbiased analysis of differentially expressed genes in tissue revealed a strong IFN signature that was significantly enriched in EoE patients as compared with patients with gastroesophageal reflux disease. Both type I and type II IFN-responsive genes were upregulated in adult biopsies, but not in blood. A similar increase in expression of IFN gene sets was observed in pediatric EoE biopsies as compared with non-EoE samples, and in public pediatric and adult RNA-sequencing data. Finally, we found that human peripheral CD4+ T cells from children with EoE produce IFN-γ upon activation with EoE-causal allergens. Together, this work identifies a conserved IFN signature in pediatric and adult EoE, highlighting a role for non-type 2 inflammatory networks in the disease process in humans.

Heterozygous FOXN1 Variants Cause Low TRECs and Severe T Cell Lymphopenia, Revealing a Crucial Role of FOXN1 in Supporting Early Thymopoiesis.

FOXN1 is the master regulatory gene of thymic epithelium development. FOXN1 deficiency leads to thymic aplasia, alopecia, and nail dystrophy, accounting for the nude/severe combined immunodeficiency (nu/SCID) phenotype in humans and mice. We identified several newborns with low levels of T cell receptor excision circles (TRECs) and T cell lymphopenia at birth, who carried heterozygous loss-of-function FOXN1 variants. Longitudinal analysis showed persistent T cell lymphopenia during infancy, often associated with nail dystrophy. Adult individuals with heterozygous FOXN1 variants had in most cases normal CD4+ but lower than normal CD8+ cell counts. We hypothesized a FOXN1 gene dosage effect on the function of thymic epithelial cells (TECs) and thymopoiesis and postulated that these effects would be more prominent early in life. To test this hypothesis, we analyzed TEC subset frequency and phenotype, early thymic progenitor (ETP) cell count, and expression of FOXN1 target genes (Ccl25, Cxcl12, Dll4, Scf, Psmb11, Prss16, and Cd83) in Foxn1nu/+ (nu/+) mice and age-matched wild-type (+/+) littermate controls. Both the frequency and the absolute count of ETP were significantly reduced in nu/+ mice up to 3 weeks of age. Analysis of the TEC compartment showed reduced expression of FOXN1 target genes and delayed maturation of the medullary TEC compartment in nu/+ mice. These observations establish a FOXN1 gene dosage effect on thymic function and identify FOXN1 haploinsufficiency as an important genetic determinant of T cell lymphopenia at birth.

Posttreatment Gene Scores Support Histologic and Endoscopic Response Thresholds in Eosinophilic Esophagitis.

INTRODUCTION: The correlation between clinical and molecular treatment response thresholds in eosinophilic esophagitis (EoE) is not well understood. METHODS: We evaluated posttreatment EoE diagnostic panel gene expression profiles across histologic and endoscopic thresholds (EREFS) in a prospective adult EoE cohort. RESULTS: We observed a strong inverse correlation between posttreatment gene score and eosinophil count (R = -0.66; P < 0.001); biopsies with <15 eos/hpf had higher gene scores (≥425) vs those with ≥15 eos/hpf. Findings for EREFS were similar; EREFS ≤2 was associated with EoE diagnostic panel scores ≥395. DISCUSSION: Molecular signatures support the use of posttreatment response thresholds <15 eos/hpf and EREFS ≤2 in clinical practice and trials.

Improvement in eosinophilic esophagitis when using dupilumab for other indications or compassionate use.

BACKGROUND: Dupilumab has been approved to treat atopic dermatitis, asthma, and nasal polyps and is in active clinical trials for the treatment of eosinophilic esophagitis (EoE). Given its shared immunopathology, we hypothesized that EoE symptoms and inflammation would improve when dupilumab therapy was used for other allergic indications. OBJECTIVE: To measure the clinical and histologic response in EoE to dupilumab when treating other atopic diseases. METHODS: We completed a retrospective chart review of all patients at Children's Hospital of Philadelphia and Rady Children Hospital who were prescribed dupilumab for atopic dermatitis, asthma, or nasal polyps and had a concomitant clinical diagnosis of EoE. Demographic information along with histology, symptom scores, medications, and diet information were collected. Response to dupilumab was evaluated. RESULTS: A total of 45 patients were identified. Of which, 11 patients were prescribed dupilumab for asthma, 27 for atopic dermatitis, 3 for nasal polyps, and 4 for compassionate use for EoE. There was no follow-up data for 8 patients. Follow-up histology was available for 26 patients: 22 of 26 had less than 6 eosinophils per high power field after the initiation of dupilumab with significant improvement (pre: 52.9 + 35.1 to post: 4.5 + 10.9 eosinophils/high power field, P < .005). A total of 28 patients had improvement of symptoms, with 24 patients reporting complete resolution of symptoms after dupilumab initiation. Reductions in EoE treatment medications (swallowed steroids, proton pump inhibitors) or expansion of diet occurred in 29 patients treated with dupilumab. CONCLUSION: Dupilumab therapy initiated for atopic disease effectively induces symptomatic and histologic remission of esophageal disease and reduces the need for EoE-directed therapy in patients with concomitant EoE.

Type 2 Immunity and Age Modify Gene Expression of Coronavirus-induced Disease 2019 Receptors in Eosinophilic Gastrointestinal Disorders.

ABSTRACT: Infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) can lead to coronavirus-induced disease 2019 (COVID-19). The gastrointestinal (GI) tract is now an appreciated portal of infection. SARS-CoV-2 enters host cells via angiotensin-converting enzyme-2 (ACE2) and the serine protease TMPRSS2. Eosinophilic gastrointestinal disorders (EGIDs) are inflammatory conditions caused by chronic type 2 (T2) inflammation. the effects of the T2 atopic inflammatory milieu on SARS-COV-2 viral entry gene expression in the GI tract is poorly understood. We analyzed tissue ACE2 and TMPRSS2 gene expression in pediatric eosinophilic esophagitis (EoE), eosinophilic gastritis (EG), and in normal adult esophagi using publicly available RNA-sequencing datasets. Similar to findings evaluating the airway, there was no difference in tissue ACE2/TMPRSS2 expression in EoE or EG when compared with control non-EoE/EG esophagus/stomach. ACE2 gene expression was significantly lower in esophagi from children with or without EoE and from adults with EoE as compared with normal adult esophagi. Type 2 immunity and pediatric age could be protective for infection by SARS-CoV-2 in the gastrointestinal tract because of decreased expression of ACE2.

Phenotypes and endotypes in eosinophilic esophagitis.

OBJECTIVE: To improve understanding of the heterogeneous presentation of eosinophilic esophagitis (EoE), and its different potential phenotypes and endotypes. DATA SOURCES: We reviewed studies addressing EoE genetics, risks, natural history, treatment, phenotype, or endotype to assess data relating to differences in the presentation of EoE in children and adults. This review was restricted to articles in the English language. STUDY SELECTIONS: Data source abstracts, pertinent articles, and book chapters meeting the objectives were critically reviewed. RESULTS: Data to support differing phenotypes and endotypes in EoE are emerging, but findings are based on multiple studies and therefore sometimes incomparable. Like other atopic disorders EoE is a complex disease with diverse clinical presentations (phenotypes) based on response to therapy, natural history, and association with atopic comorbidities. Different pathogenetic mechanisms (endotypes) may drive the multiple phenotypes. T Helper type 2 inflammation, epithelial barrier defects, enhanced fibrosis, and association with rare monogenetic diseases are the most described endotypes in EoE. CONCLUSION: Eosinophilic esophagitis is an atopic disorder that is increasing in prevalence and can be difficult to treat. Better understanding of phenotypes and endotypes in EoE may enable future care to be individualized more effectively, resulting in shorter time to remission and fewer endoscopies.

The Role of Eosinophils in Immunotherapy.

PURPOSE OF REVIEW: The purpose of this review is to provide a brief discussion on the differential diagnosis for peripheral eosinophilia. We will then focus on targeted immunotherapies for atopic disease, their effects on absolute peripheral eosinophil counts, and use of peripheral eosinophils as a predictor of treatment response. RECENT FINDINGS: In atopic disease, lower absolute peripheral eosinophil counts are typically associated with improved outcomes. Much of the current evidence on eosinophils as a biomarker comes from post hoc analyses in therapeutic immunotherapy. While changes in eosinophilia were not the primary outcome of interest in many studies, some patterns did emerge. Cytolytic monoclonal antibodies AK002 and benralizumab completely reduce peripheral and tissue eosinophil numbers. Dupilumab may have paradoxical transient eosinophilia despite observed clinical efficacy. Atopic inflammation is complex largely due to the various cytokines which affect eosinophil activation, proliferation, differentiation, and survival. This demonstrates the challenges of using peripheral eosinophilia alone as a biomarker for atopic disease activity. More attention should spotlight how different immunotherapy modalities affect eosinophil-driven responses.

Common variable immunodeficiency-associated endotoxemia promotes early commitment to the T follicular lineage.

BACKGROUND: Although chiefly a B-lymphocyte disorder, several research groups have identified common variable immunodeficiency (CVID) subjects with numeric and/or functional TH cell alterations. The causes, interrelationships, and consequences of CVID-associated CD4+ T-cell derangements to hypogammaglobulinemia, autoantibody production, or both remain unclear. OBJECTIVE: We sought to determine how circulating CD4+ T cells are altered in CVID subjects with autoimmune cytopenias (AICs; CVID+AIC) and the causes of these derangements. METHODS: Using hypothesis-generating, high-dimensional single-cell analyses, we created comprehensive phenotypic maps of circulating CD4+ T cells. Differences between subject groups were confirmed in a large and genetically diverse cohort of CVID subjects (n = 69) by using flow cytometry, transcriptional profiling, multiplex cytokine/chemokine detection, and a suite of in vitro functional assays measuring naive T-cell differentiation, B-cell/T-cell cocultures, and regulatory T-cell suppression. RESULTS: Although CD4+ TH cell profiles from healthy donors and CVID subjects without AICs were virtually indistinguishable, T cells from CVID+AIC subjects exhibited follicular features as early as thymic egress. Follicular skewing correlated with IgA deficiency-associated endotoxemia and endotoxin-induced expression of activin A and inducible T-cell costimulator ligand. The resulting enlarged circulating follicular helper T-cell population from CVID+AIC subjects provided efficient help to receptive healthy donor B cells but not unresponsive CVID B cells. Despite this, circulating follicular helper T cells from CVID+AIC subjects exhibited aberrant transcriptional profiles and altered chemokine/cytokine receptor expression patterns that interfered with regulatory T-cell suppression assays and were associated with autoantibody production. CONCLUSIONS: Endotoxemia is associated with early commitment to the follicular T-cell lineage in IgA-deficient CVID subjects, particularly those with AICs.

Toll-like receptor 2 stimulation augments esophageal barrier integrity.

BACKGROUND: Germline-encoded innate immune pattern recognition receptors (PRR) are expressed at epithelial surfaces and modulate epithelial defenses. Evidence suggests that stimulation of the Toll-like receptor (TLR) family of PRR may regulate epithelial barrier integrity by upregulating tight junction (TJ) complex protein expression, but it is not known whether this mechanism is utilized in esophageal epithelial cells. TJ complex proteins maintain intact barrier function and are dysregulated in atopic disorders including eosinophilic esophagitis. METHODS: Pattern recognition receptors expression was assessed in EoE and control primary esophageal epithelial cells, demonstrating robust expression of TLR2 and TLR3. The three-dimensional air-liquid interface culture (ALI) model was used to test whether TLR2 or TLR3 stimulation alters epithelial barrier function using an in vitro model of human epithelium. Transepithelial electrical resistance (TEER) and FITC-Dextran permeability were evaluated to assess membrane permeability. ALI cultures were evaluated by histology, immunohistochemistry, Western blotting, and chromatin immunoprecipitation (ChIP). RESULTS: TLR3 stimulation did not change TEER in the ALI model. TLR2 stimulation increased TEER (1.28- to 1.31-fold) and decreased paracellular permeability to FITC-Dextran, and this effect was abolished by treatment with anti-TLR2 blocking antibody. TJ complex proteins claudin-1 and zonula occludens-1 were upregulated following TLR2 stimulation, and ChIP assay demonstrated altered histone 4 acetyl binding at the TJP1 enhancer and CLDN1 enhancer and promoter following zymosan treatment, implying the occurrence of durable chromatin changes. CONCLUSIONS: Our findings implicate the TLR2 pathway as a potential regulator of esophageal epithelial barrier function and suggest that downstream chromatin modifications are associated with this effect.

Complications Associated with Underweight Primary Immunodeficiency Patients: Prevalence and Associations Within the USIDNET Registry.

PURPOSE: The point prevalence of underweight status and obesity in primary immunodeficiency disease (PID) is unknown, despite the described associations between PID and weight loss and failure to thrive. The goal of this study is to estimate the prevalence of underweight status and obesity in PID patients and to investigate the associations between abnormal body weight and complications of PID. METHODS: Using the US Immunodeficiency Network (USIDNET), we performed a retrospective analysis of 653 pediatric (age 2 to 20 years) and 514 adult (age > 20) patient records with information on patient body mass index (BMI). Prevalence of underweight and obese status in PID patients was compared to data from the National Health and Nutrition Examination Survey (NHANES). RESULTS: After separating BMI data by year of entry to the database, we demonstrated that both adult and pediatric patients with PID had significantly higher prevalence of underweight patients in multiple years of analysis. Further examination of underweight patients by PID diagnosis revealed that underweight status in adults with CVID was associated with granulomatous disease as well as earlier age of CVID diagnosis. In the pediatric CVID cohort, underweight status was significantly associated with lymphopenia. Examination of obesity in pediatric and adult PID patients compared to NHANES database revealed only a single year when obesity in PID patients was significantly less prevalent. In other 2-year time intervals from 2005 to 2014, the prevalence of obesity was unchanged in children and adults. CONCLUSIONS: These results quantify the prevalence of underweight status in PID in a North American population and demonstrate that whether as a result of weight loss or poor weight gain, underweight status is more prevalent in the PID population than in the general US population. The prevalence of obesity in PID patients was similar to that seen in the general population. This highlights the need for continued education on the association of low weight and PID. CLINICAL TRIAL REGISTRATION: NCT01953016.

Variable immune deficiency related to deletion size in chromosome 22q11.2 deletion syndrome.

The clinical features of 22q11.2 deletion syndrome include virtually every organ of the body. This review will focus on the immune system and the differences related to deletion breakpoints. A hypoplastic thymus was one of the first features described in this syndrome and low T cell counts, as a consequence of thymic hypoplasia, are the most commonly described immunologic feature. These are most prominently seen in early childhood and can be associated with increased persistence of viruses. Later in life, evidence of T cell exhaustion may be seen and secondary deficiencies of antibody function have been described. The relationship of the immunodeficiency to the deletion breakpoints has been understudied due to the infrequent analysis of people carrying smaller deletions. This manuscript will review the immune deficiency in 22q11.2 deletion syndrome and describe differences in the T cell counts related to the deletion breakpoints. Distal, non-TBX1 inclusive deletions, were found to be associated with better T cell counts. Another new finding is the relative preservation of T cell counts in those patients with a 22q11.2 duplication.

Pediatric eosinophilic esophagitis: updates for the primary care setting.

PURPOSE OF REVIEW: Eosinophilic esophagitis (EoE) is a multifactorial, non-IgE-mediated inflammatory disorder of the esophagus and is the most common cause of food impaction in the pediatric population. The purpose of this review is to describe the current recommendations for diagnosis and management of EoE. RECENT FINDINGS: New data has associated EoE with other allergic disorders of the atopic march as well as several risk factors, which predispose to allergic conditions. A subset of patients with esophageal eosinophilia respond to proton pump inhibitor (PPI) therapy with a partial or complete resolution of esophageal eosinophilia. Therefore, some patients can be treated with PPI alone. If this is unsuccessful, dietary elimination and swallowed steroid therapy are recommended for long-term management. There is a growing appreciation that untreated esophageal inflammation can lead to complications of fibrosis and stricture formation. SUMMARY: The current review will focus on the diagnosis and management of EoE in the pediatric population. Identification and diagnosis of pediatric patients with EoE is critical to prevent long-term esophageal complications.