Esophageal IgG4 levels correlate with histopathologic and transcriptomic features in eosinophilic esophagitis.

BACKGROUND: Recent data associate eosinophilic esophagitis (EoE) with IgG4 rather than IgE, but its significance and function have not been determined. Our aims were to measure esophageal IgG4 levels and to determine functional correlations as assessed by histologic and transcriptome analyses. METHODS: This case-control study included pediatric subjects with EoE (≥15 eosinophils/HPF) and non-EoE controls. Protein lysates were analyzed for IgA, IgM, and IgG1-IgG4 using the Luminex 100 system; IgE was quantified by ELISA. Esophageal biopsies were scored using the EoE histology scoring system. Transcripts were probed by the EoE diagnostic panel, designed to examine the expression of 96 esophageal transcripts. RESULTS: Esophageal IgG subclasses, IgA, and IgM, but not IgE, were increased in subjects with EoE relative to controls. The greatest change between groups was seen in IgG4 (4.2 mg/g protein [interquartile range: 1.0-13.1 mg/g protein] vs 0.2 mg/g protein [0.1-0.9]; P < .0001). Tissue IgG4 levels correlated with esophageal eosinophil counts (P = .0006); histologic grade (P = .0011) and stage (P = .0112) scores; and IL4, IL10, IL13, but not TGFB1, expression and had strong associations with a subset of the EoE transcriptome. Esophageal IgG4 transcript expression was increased and correlated with IgG4 protein levels and IL10 expression. CONCLUSION: These findings extend prior studies on IgG4 in adult EoE to the pediatric population and provide deeper understanding of the potential significance and regulation of IgG4, demonstrating that IgG4 is a relevant feature of the disease; is closely related to esophageal eosinophil levels, type 2 immunity and T regulatory cytokines; and is likely produced locally.

Newly developed and validated eosinophilic esophagitis histology scoring system and evidence that it outperforms peak eosinophil count for disease diagnosis and monitoring.

Eosinophilic esophagitis (EoE) is diagnosed by symptoms, and at least 15 intraepithelial eosinophils per high power field in an esophageal biopsy. Other pathologic features have not been emphasized. We developed a histology scoring system for esophageal biopsies that evaluates eight features: eosinophil density, basal zone hyperplasia, eosinophil abscesses, eosinophil surface layering, dilated intercellular spaces (DIS), surface epithelial alteration, dyskeratotic epithelial cells, and lamina propria fibrosis. Severity (grade) and extent (stage) of abnormalities were scored using a 4-point scale (0 normal; 3 maximum change). Reliability was demonstrated by strong to moderate agreement among three pathologists who scored biopsies independently (P ≤ 0.008). Several features were often abnormal in 201 biopsies (101 distal, 100 proximal) from 104 subjects (34 untreated, 167 treated). Median grade and stage scores were significantly higher in untreated compared with treated subjects (P ≤ 0.0062). Grade scores for features independent of eosinophil counts were significantly higher in biopsies from untreated compared with treated subjects (basal zone hyperplasia P ≤ 0.024 and DIS P ≤ 0.005), and were strongly correlated (R-square >0.67). Principal components analysis identified three principal components that explained 78.2% of the variation in the features. In logistic regression models, two principal components more closely associated with treatment status than log distal peak eosinophil count (PEC) (R-square 17, area under the curve (AUC) 77.8 vs. R-square 9, AUC 69.8). In summary, the EoE histology scoring system provides a method to objectively assess histologic changes in the esophagus beyond eosinophil number. Importantly, it discriminates treated from untreated patients, uses features commonly found in such biopsies, and is utilizable by pathologists after minimal training. These data provide rationales and a method to evaluate esophageal biopsies for features in addition to PEC.

Analysis and expansion of the eosinophilic esophagitis transcriptome by RNA sequencing.

Eosinophilic esophagitis (EoE) is an allergic inflammatory disorder of the esophagus that is compounded by genetic predisposition and hypersensitivity to environmental antigens. Using high-density oligonucleotide expression chips, a disease-specific esophageal transcript signature was identified and was shown to be largely reversible with therapy. In an effort to expand the molecular signature of EoE, we performed RNA sequencing on esophageal biopsies from healthy controls and patients with active EoE and identified a total of 1607 significantly dysregulated transcripts (1096 upregulated, 511 downregulated). When clustered by raw expression levels, an abundance of immune cell-specific transcripts are highly induced in EoE but expressed at low (or undetectable) levels in healthy controls. Moreover, 66% of the gene signature identified by RNA sequencing was previously unrecognized in the EoE transcript signature by microarray-based expression profiling and included several long non-coding RNAs (lncRNA), an emerging class of transcriptional regulators. The lncRNA BRAF-activated non-protein coding RNA (BANCR) was upregulated in EoE and induced in interleukin-13 (IL-13)-treated primary esophageal epithelial cells. Repression of BANCR significantly altered the expression of IL-13-induced proinflammatory genes. Together, these data comprise new potential biomarkers of EoE and demonstrate a novel role for lncRNAs in EoE and IL-13-associated responses.

Local B cells and IgE production in the oesophageal mucosa in eosinophilic oesophagitis.

BACKGROUND: Eosinophilic oesophagitis (EO) is an emerging yet increasingly prevalent disorder characterised by a dense and selective eosinophilic infiltration of the oesophageal wall. While EO is considered an atopic disease primarily triggered by food antigens, disparities between standard allergen testing and clinical responses to exclusion diets suggest the participation of distinct antigen-specific immunoglobulin E (IgE) in the pathophysiology of EO. AIM: To find evidence for a local IgE response. METHODS: Endoscopic biopsies of the distal oesophagus of atopic and non-atopic EO and control individuals (CTL) were processed for immunohistochemistry and immunofluorescence to assess the presence of B cells, mast cells, and IgE-bearing cells. Oesophageal RNA was analysed for the expression of genes involved in B cell activation, class switch recombination to IgE and IgE production, including germline transcripts (GLTs), activation-induced cytidine deaminase (AID), IgE heavy chain (Cepsilon) and mature IgE mRNA using polymerase chain reaction and microarray analysis. RESULTS: Regardless of atopy, EO showed increased density of B cells (p<0.05) and of IgE-bounded mast cells compared to CTL. Both EO and CTL expressed muGLT, epsilonGLT, gamma4GLT, AID, Cepsilon and IgE mRNA. However, the frequency of expression of total GLTs (p = 0.002), epsilonGLT (p = 0.024), and Cepsilon (p = 0.0003) was significantly higher in EO than in CTL, independent of the atopic status. CONCLUSION: These results support the heretofore unproven occurrence of both local immunoglobulin class switching to IgE and IgE production in the oesophageal mucosa of EO patients. Sensitisation and activation of mast cells involving local IgE may therefore critically contribute to disease pathogenesis.

Eosinophilic esophagitis.

Eosinophilic esophagitis (EoE) is a chronic, eosinophil-predominant inflammatory condition that can affect esophageal mucosa at any age. Distinguished from gastroesophageal reflux disease in the mid 1990's, it has seemed to be increasingly prevalent, and is usually a manifestation of food allergy. The endoscopic and histologic features are well described. The clinical manifestations vary considerably by age, with adolescents and adults complaining primarily of dysphagia. Younger children may present with pain, vomiting, other evidence for food allergy, or feeding difficulties. Treatment options include swallowed (non-systemic) steroids and dietary antigen elimination, and must be maintained indefinitely due to the extremely high rate of recurrence off therapy. The complications of untreated disease include fibrosis of the esophageal lamina propria and stricture formation that result in chronic dysphagia, risking food impaction and perforation.

Cadherin 26 is an alpha integrin-binding epithelial receptor regulated during allergic inflammation.

Cadherins (CDH) mediate diverse processes critical in inflammation, including cell adhesion, migration, and differentiation. Herein, we report that the uncharacterized cadherin 26 (CDH26) is highly expressed by epithelial cells in human allergic gastrointestinal tissue. In vitro, CDH26 promotes calcium-dependent cellular adhesion of cells lacking endogenous CDHs by a mechanism involving homotypic binding and interaction with catenin family members (alpha, beta, and p120), as assessed by biochemical assays. Additionally, CDH26 enhances cellular adhesion to recombinant integrin α4ß7 in vitro; conversely, recombinant CDH26 binds αE and α4 integrins in biochemical and cellular functional assays, respectively. Interestingly, CDH26-Fc inhibits activation of human CD4+ T cells in vitro including secretion of IL-2. Taken together, we have identified a novel functional CDH regulated during allergic responses with unique immunomodulatory properties, as it binds α4 and αE integrins and regulates leukocyte adhesion and activation, and may thus represent a novel checkpoint for immune regulation and therapy via CDH26-Fc.

Cricopharyngeal dysfunction associated with Chiari malformations.

UNLABELLED: Dysphagia due to upper esophageal sphincter (UES) dysfunction can be a manifestation of Chiari malformation. We evaluated five young children with dysphagia and a Chiari malformation before and after craniocervical decompression. Preoperatively, esophageal manometry with a multilumen perfused catheter revealed failure of complete relaxation of the UES in three patients, pharyngo-UES incoordination in one patient, and both abnormalities in the last patient. Preoperative barium esophagograms were obtained in four of the patients and were normal in two. One patient had nasal regurgitation of barium and delayed passage of barium through the UES. One patient had a posterior pharyngeal impression (bar) at the level of the UES and delayed transit of barium. All patients had clinical and manometric resolution of UES dysfunction following surgical decompression of the Chiari malformation. All swallows were coordinated, and UES relaxations were complete. However, the posterior pharyngeal bar persisted on postoperative esophagogram in the only patient who had had the abnormality preoperatively, although it no longer interfered with passage of barium. Another patient had a narrowed UES with decreased relaxation. Swallowing was radiographically normal in three patients postoperatively. CONCLUSION: Surgical decompression of Chiari malformation may lead to complete clinical and manometric resolution of dysphagia due to upper esophageal sphincter dysfunction. Esophageal manometry is more likely than barium swallow to demonstrate the abnormality, and correlates better with symptomatic improvement postoperatively.

Rectal bleeding in Prader-Willi syndrome.

Individuals with Prader-Willi syndrome manifest severe skin picking behavior. We report three patients with this syndrome in whom an extension of this behavior to rectal picking resulted in significant lower gastrointestinal bleeding and anorectal disease. The recognition of this behavior is important to avoid misdiagnosing inflammatory bowel disease in this group of patients.

Laryngeal cleft and eosinophilic gastroenteritis: report of 2 cases.

Although laryngotracheoesophageal clefts are often found in association with other well-described anomalies, we know of no previous reported association with eosinophilic gastroenteritis, a disorder of unknown etiology characterized by eosinophilic infiltration of the gastrointestinal tract. We treated 2 children who had laryngeal clefts and eosinophilic gastroenteritis. Since the esophageal inflammatory changes found in eosinophilic gastroenteritis may persist despite aggressive therapy, management of the laryngotracheoesophageal clefts is more complicated. The diagnosis of eosinophilic gastroenteritis should not be overlooked in patients with laryngotracheoesophageal clefts and warrants prompt referral to a pediatric gastroenterologist.

Prevalence and characteristics of Blastocystis hominis infection in children.

Blastocystis hominis, a protozoan whose pathogenicity has been questioned, is sometimes found in the human gastrointestinal tract. We sought to determine the prevalence of Blastocystis in stool and to characterize clinical features of infection with Blastocystis in children. Forty-six (3%) of 1,736 patients undergoing fecal microscopy at Children's Hospital of Pittsburgh between January 1, 1985, and December 31, 1988, harbored Blastocystis. Of these 46 children, 75% had exposure to well water or had been in developing countries. Thirty-nine of the 46 (85%) experienced gastrointestinal symptoms, such as abdominal pain, diarrhea, vomiting, and weight loss. Blastocystis was the only parasite found in 35 of those 39 symptomatic children. Symptoms resolved within one month in 90% of patients receiving antiparasitic pharmacotherapy, but in only 58% (P < .04) of those receiving no therapy. We conclude that children infected with Blastocystis often experience gastrointestinal symptoms and that treatment increases the rate of symptomatic improvement. We speculate that Blastocystis is a human pathogen.

Desmoglein-1 regulates esophageal epithelial barrier function and immune responses in eosinophilic esophagitis.

The desmosomal cadherin desmoglein-1 (DSG1) is an essential intercellular adhesion molecule that is altered in various human cutaneous disorders; however, its regulation and function in allergic disease remains unexplored. Herein, we demonstrate a specific reduction in DSG1 in esophageal biopsies from patients with eosinophilic esophagitis (EoE), an emerging allergic disorder characterized by chronic inflammation within the esophageal mucosa. Further, we show that DSG1 gene silencing weakens esophageal epithelial integrity, and induces cell separation and impaired barrier function (IBF) despite high levels of desmoglein-3. Moreover, DSG1 deficiency induces transcriptional changes that partially overlap with the transcriptome of inflamed esophageal mucosa; notably, periostin (POSTN), a multipotent pro-inflammatory extracellular matrix molecule, is the top induced overlapping gene. We further demonstrate that IBF is a pathological feature in EoE, which can be partially induced through the downregulation of DSG1 by interleukin-13 (IL-13). Taken together, these data identify a functional role for DSG1 and its dysregulation by IL-13 in the pathophysiology of EoE and suggest that the loss of DSG1 may potentiate allergic inflammation through the induction of pro-inflammatory mediators such as POSTN.

Periostin facilitates eosinophil tissue infiltration in allergic lung and esophageal responses.

Periostin is an extracellular matrix protein that has been primarily studied in the context of the heart, where it has been shown to promote cardiac repair and remodeling. In this study, we focused on the role of periostin in an allergic eosinophilic inflammatory disease (eosinophilic esophagitis (EE)) known to involve extensive tissue remodeling. Periostin was indeed markedly overexpressed (35-fold) in the esophagus of EE patients, particularly in the papillae, compared with control individuals. Periostin expression was downstream from transforming growth factor-beta and interleukin-13, as these cytokines were elevated in EE esophageal samples and markedly induced periostin production by primary esophageal fibroblasts (107- and 295-fold, respectively, at 10 ng ml(-1)). A functional role for periostin in eliciting esophageal eosinophilia was demonstrated, as periostin-null mice had a specific defect in allergen-induced eosinophil recruitment to the lungs and esophagus (66 and 72% decrease, respectively). Mechanistic analyses revealed that periostin increased (5.8-fold) eosinophil adhesion to fibronectin. As such, these findings extend the involvement of periostin to esophagitis and uncover a novel role for periostin in directly regulating leukocyte (eosinophil) accumulation in T helper type 2-associated mucosal inflammation in both mice and humans.

Gastroesophageal reflux disease and dysphagia in children.

Gastroesophageal reflux disease (GERD) is a common problem in children that is sometimes associated with dysphagia. Choking, food refusal, and food "getting stuck" are non-specific symptoms that may arise consequent to reflux and esophagitis. Swallowing plays a role in reflux physiology, functioning as a major clearance mechanism after reflux episodes. Therefore, failure of swallowing to effectively perform that function contributes to reflux pathophysiology. The diagnosis and treatment of GERD in children must be carried out systematically and thoroughly. Multiple interacting factors are common, thus complicating the process.

Prokinetic agents.

Prokinetic agents are medications that promote gastrointestinal motility. This article reflects the current state of our understanding of their mechanisms of action and their clinical utility in treating disorders of gastrointestinal motility, including gastroesophageal reflux, gastroparesis, small-intestinal dysmotility, and constipation.

Determining esophageal length from crown-rump length.

Since esophageal length varies linearly with height, intraluminal pH monitoring can be performed at a position within the esophagus that is determined by an equation. Alternatively, pH probes can be positioned under fluoroscopic guidance, though no radiographic landmarks indicate the position that is 87% of esophageal length (where the monitoring is usually accomplished). Our aims were to determine whether a relationship might exist between crown-rump length and esophageal length, for use in patients in whom height is difficult or inappropriate to measure, and to determine whether the mid-right atrium can be used as a radiographic landmark in fluoroscopic pH probe placement. Height, crown-rump length, and distance from the suprasternal notch to the left anterior superior iliac spine were measured in 65 consecutive children undergoing 24-h pH monitoring. As the pH probe was inserted under fluoroscopy, distances from the nose to diaphragm and mid-right atrium were determined. Equations were derived by simple linear regression to describe the relationships between each of the body measurements and esophageal length. There is excellent correlation between crown-rump length and the distances from the nose to diaphragm and to mid-right atrium. The mid-right atrium corresponds to 87% of the nose to diaphragm distance in many patients.

Hoarseness in a child with gastroesophageal reflux.

Hoarseness is not generally appreciated to be a manifestation of pediatric gastroesophageal reflux. We describe a case in which treatment of well-documented gastroesophageal reflux and esophagitis in a young girl with hoarseness and nocturnal cough led to resolution of these symptoms. Possible pathogenetic mechanisms and the difficulty in associating hoarseness with reflux by standard reflux testing are discussed.

Gastrointestinal bleeding due to delayed perianastomotic ulceration in children.

Delayed perianastomotic ulcers are a poorly recognized complication of intestinal surgery. We report two patients with this complication of their remote intestinal surgery who developed significant iron deficiency anemia. Patient 1 had intestinal resection for perforated necrotizing enterocolitis as a newborn and presented at 16 yr of age with an ulcer at the ileocolonic anastomosis. Patient 2 had intestinal resection for strangulated internal hernia at 9 yr and was diagnosed with two ulcers at the ileoileal anastomosis at 14 yr of age. Fifteen patients with delayed anastomotic ulcers have so far been reported in the literature. We add two more cases and also emphasize the difficulty in establishing the diagnosis and importance of performing a retrograde ileoscopy.