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.

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 α4β7 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.

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.

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.

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.

RATIONALE: We aimed to determine the molecular basis of the pathogenesis of eosinophilic gastritis (EG).METHODS: Global transcript analysis was employed to identify genes regulated differentially in the gastric tissue of pediatric patients with active EG compared to normal patients. Further characterization of the gene and protein expression patterns of the most highly upregulated gene, CDH26, was undertaken through RT-PCR, immunohistochemistry, and western blot analysis. Cdh26 protein interactions were examined using transient transfection and immunoprecipitation analysis.RESULTS: We identified 104 transcripts that exhibited differential regulation between normal gastric tissue and that of patients with EG. Of these, 28 were upregulated, while 76 were downregulated. In addition, IL-13 transcript levels were increased on average 375-fold (p<0.01) in the gastric tissue of patients with EG. The protein encoded by the most highly upregulated gene, cadherin-like 26 (CDH26), was highly expressed in the gastric epithelium of patients with EG. Furthermore, IL-13 induced CDH26 expression in the gastric cell line NCI-N87 in vitro. Cdh26, a putative type-I cadherin molecule, exhibited homotypic interaction and additionally interacted with beta-catenin, alpha-catenin, and delta-catenin (p120) when expressed ectopically in 293T cells.CONCLUSIONS: We gained insight into the pathogenesis of EG by identifying a transcript signature of the gastric tissue of EG patients. Our data suggest the most highly upregulated transcript, CDH26, may be regulated in part by IL-13 in gastric epithelial cells. Cdh26 interacts with catenin proteins, which link cadherin molecules to the actin cytoskeleton. Furthermore, Cdh26 exhibits homotypic interaction, consistent with a function of Cdh26 in cell adhesion. RATIONALE: We aimed to determine the molecular basis of the pathogenesis of eosinophilic gastritis (EG). METHODS: Global transcript analysis was employed to identify genes regulated differentially in the gastric tissue of pediatric patients with active EG compared to normal patients. Further characterization of the gene and protein expression patterns of the most highly upregulated gene, CDH26, was undertaken through RT-PCR, immunohistochemistry, and western blot analysis. Cdh26 protein interactions were examined using transient transfection and immunoprecipitation analysis. RESULTS: We identified 104 transcripts that exhibited differential regulation between normal gastric tissue and that of patients with EG. Of these, 28 were upregulated, while 76 were downregulated. In addition, IL-13 transcript levels were increased on average 375-fold (p<0.01) in the gastric tissue of patients with EG. The protein encoded by the most highly upregulated gene, cadherin-like 26 (CDH26), was highly expressed in the gastric epithelium of patients with EG. Furthermore, IL-13 induced CDH26 expression in the gastric cell line NCI-N87 in vitro. Cdh26, a putative type-I cadherin molecule, exhibited homotypic interaction and additionally interacted with beta-catenin, alpha-catenin, and delta-catenin (p120) when expressed ectopically in 293T cells. CONCLUSIONS: We gained insight into the pathogenesis of EG by identifying a transcript signature of the gastric tissue of EG patients. Our data suggest the most highly upregulated transcript, CDH26, may be regulated in part by IL-13 in gastric epithelial cells. Cdh26 interacts with catenin proteins, which link cadherin molecules to the actin cytoskeleton. Furthermore, Cdh26 exhibits homotypic interaction, consistent with a function of Cdh26 in cell adhesion.

BACKGROUND:Eosinophilic esophagitis (EE) is an emerging disorder with poorly understood pathogenesis. OBJECTIVE:Whereas prior studies have primarily focused on the role of eosinophils in disease diagnosis and pathogenesis, this study investigates the involvement of mast cells. METHODS:Total and degranulated mast cell counts were correlated to microarray and RT-PCR data to generate transcriptome expression profiles related to mast cell number and degranulation in patients with EE and healthy control subjects. RESULTS:Esophageal mastocytosis and mast cell degranulation were readily apparent in patients with EE compared with control subjects (P < .01), as assessed by staining for total mast cells and the presence of extracellular mast cell tryptase (P < .01). Microarray analysis revealed that mast cell levels correlated with the dysregulation of 0.8% (301 genes) of the genome, which was partially distinct from the genes that correlated with tissue eosinophilia. The expression of transcripts for the mast cell proteases carboxypeptidase A3 and tryptase, but not chymase, correlated with mast cell levels and distinguished patients with EE from control subjects. Suprabasilar mast cell counts (P < .01) and degranulation (P < .01) were proportional with KIT ligand mRNA expression. Treatment of patients with EE with swallowed fluticasone propionate normalized levels of mast cells and the mast cell-related transcriptome in responder patients. CONCLUSION:Herein we have identified local mastocytosis and mast cell degranulation in the esophagi of patients with EE; identified an esophageal mast cell-associated transcriptome that is significantly divergent from the eosinophil-associated transcriptome, with carboxypeptidase A3 mRNA levels serving as the best mast cell surrogate marker; and provided evidence for the involvement of KIT ligand in the pathogenesis of EE.

RATIONALE: The data on the quantity and location of mast cells (MCs) through the gastrointestinal tract of healthy children are lacking, and we sought to establish baseline values for MCs in varied segments of the gastrointestinal tract. METHODS: Gastrointestinal (GI) biopsies without diagnostic abnormality were reviewed from 32 pediatric patients. Mast cells were stained for either tryptase or CD117 and enumerated per high powered field (hpf). RESULTS: In the distal esophagus, tryptase staining demonstrated 0.18 ± 0.31 MC/hpf (mean ± standard deviation) with a maximum of 3 MCs/hpf. Tryptase staining of the stomach body and antrum showed minimal MCs in the surface or glandular epithelium with a maximum of 2 MCs/hpf, while in the lamina propria (LP), an average of 11.5 ± 4.3 MCs/hpf was noted (maximum, 29). The duodenal villous LP contained 3.5 ± 2.4 MCs/hpf (maximum, 18) while within the intercryptal LP there were 14.5 ± 4.5 MCs/hpf (maximum, 36). Similar counts were seen for the terminal ileum with 3.4 ± 1.5 (maximum, 19) and 16.1 ± 6.7 (maximum, 42) for the villous LP and intercryptal LP respectively. In the large intestine the highest concentration of MCs was within the cecum/ascending colon LP with 19.4 MCs/hpf. Progressively lower MCs were found in the cecum/ascending colon (17.9 ± 4.4), transverse/descending colon (17.7 ± 6), and sigmoid/rectum (12.7 ± 4.3 MCs/hpf). CD117 staining demonstrated similar counts throughout the GI tract. CONCLUSIONS: Mast cells are found throughout the GI tract in healthy children, and we have established reference MC counts in several GI segments.

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.

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-β 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.

Purpose: Children with short bowel syndrome (SBS) who have gastrostomies and are on TPN may develop cholestasis and its complications including portal hypertension. However, in this group, upper GI (UGI) hemorrhage is only rarely due to esophageal varices. Instead, peri-gastrostomy varices preferentially form. We have observerd yet another cause of bleeding–namely, granulation tissue at the gastrostomy site. We conducted this study to ascertain the frequency, clinical characteristics, and outcome of this problem in our SBS population. Methods: We conducted a chart review of all children with SBS in our institution who experienced UGI bleeding between 1/2001 and 6/2005. We tabulated the number of patients who bled, the number who bled from granulation tissue, clinical characteristics, avg. blood loss, and results of endoscopic therapy. Results: Twenty seven patients had persistent cholestasis, and 15 of them underwent upper endoscopy for bleeding. Causes of bleeding were ulcers in 3, portal hypertensive gastropathy/peristomal varices in 8, and granulation tissue adjacent to the gastrostomy in 4. The granulation tissue was evident only upon deflation of the gastrostomy tube balloon during inspection of the gastrostomy site. All of those with granulation tissue had jaundice and portal hypertension when endoscoped. None of them had synthetic liver dysfunction. Average blood loss prior to endoscopy for those with granulation tissue was 10 ml/kg/wk. All four underwent argon plasma coagulation of the granulation tissue. Bleeding ceased permanently in one of them after only a single ablation. Two of the others with granulation tissue required two ablations for resolution of their bleeding. The 4th has required 3 sessions to halve the frequency of transfusions. No complications resulted from therapy. As gut adaptation took place, cholestasis and portal hypertension have resolved or are resolving in all of the group with granulation tissue. Conclusions: Granulation tissue of the gastrostomy site is a common, treatable cause of UGI bleeding in children with SBS and portal hypertension. The lesion can be visualized best if the gastrostomy balloon is deflated during inspection of the gastric body. Therapy by argon plasma coagulation appears to be safe and effective.

Journal of Pediatric Gastroenterology and NutritionVolume 39, Issue S1 p. S246-S246 ABSTRACTS: Poster Session Abstracts P0499 RESPONSE OF ESOPHAGEAL AND GASTROINTESTINAL MUCOSAL EOSINOPHILIA TO AN ELEMENTAL DIET TRIAL P. E. Putnam, P. E. Putnam Pediatric Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorA. Assa’ad, A. Assa’ad Allergy and Immunology, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorM. H. Collins, M. H. Collins Pediatric Pathology, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorR. Noel, R. Noel Pediatric Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorS. C. Jameson, S. C. Jameson Allergy and Immunology, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorR. Akers, R. Akers Center for Epidemiology and Biostatistics, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorM. E. Rothenberg, M. E. Rothenberg Allergy and Immunology, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this author P. E. Putnam, P. E. Putnam Pediatric Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorA. Assa’ad, A. Assa’ad Allergy and Immunology, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorM. H. Collins, M. H. Collins Pediatric Pathology, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorR. Noel, R. Noel Pediatric Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorS. C. Jameson, S. C. Jameson Allergy and Immunology, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorR. Akers, R. Akers Center for Epidemiology and Biostatistics, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this authorM. E. Rothenberg, M. E. Rothenberg Allergy and Immunology, Cincinnati Children’s Hospital Medical Center, Cincinnati, United StatesSearch for more papers by this author First published: 01 June 2004 https://doi.org/10.1002/j.1536-4801.2004.tb12929.x Submitted by: [email protected] Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume39, IssueS1June 2004Pages S246-S246 RelatedInformation

Little is known about natural history of anaphylaxis.In order to investigate the natural history of anaphylaxis in a pediatric population, we performed a telephone survey through a questionnaire in a cohort of 76 well characterized children referred to our Pediatric Allergy Unit for anaphylaxis between 1994 and 1996.and previously described (Novembre E, Cianferoni A, Bernardini R, et al.Anaphylaxis in children: clinical and allergologic features.Pediatrics 1998;101:E8).Data were then analyzed using chi square and a p* 0.05 was considered significant.We reached and interviewed over the phone 46 (60,3%) of them.We couldn't contact the others due to address changing, all the contacted patients answered in a cooperative and exhaustive manner.After a mean time of 7.45 years from the first episode of anaphylaxis, 30% of the studied children experienced a recurrence of anaphylaxis.Children who suffered from atopic dermatitis (AD) either in 1994-96 (64% vs 31%, p=0.04), at the time of the study (50% vs 12%, p=0.03) or persistent (42% vs 9%, p=0.0l) and those who were suffering from urticaria angioedema (OA) at the time of the study (93% vs 31%, p=0.0002) were at a significantly higher risk to develop recurrent anaphylaxis.Moreover those children, who were sensitive to at least one food allergen in 1994-1996 were more likely to experience a recurrence of anaphylaxis (93% vs 56% p<0.04).In conclusion food allergy and AD are risk factors for recurrence of anaphylaxis.

Anaphylaxis from peanuts. Buzzing lips from apple. Vomiting and diarrhea producing shock from oat. Steatorrhea from wheat. Bloody stools from breast milk. These phenomena are examples from the range of manifestations of immune reactions to foods in common pediatric experience—immediate hypersensitivity and oral allergy syndrome, food protein-induced enterocolitis syndrome, gluten-sensitive enteropathy (celiac disease), and allergic colitis. But, what about constipation from milk, eczema from eggs, dysphagia from chicken, or sleep disturbance from everything? Are they immune-mediated? Or, are they phantom associations? Certainly, every three-year-old drama queen who hasn't voluntarily opened her anal sphincter since being introduced to the porcelain monster isn't allergic to milk. Right? Right. Nevertheless, it is becoming increasingly clear that immunologic reactions to multiple foods can present in more subtle fashion than previously recognized and must be included in the broader differential diagnosis for a variety of symptoms. The outstanding article by Latcham et al in this edition of The Journal describes 121 children in Great Britain with multiple food allergies.1.Latcham F. Merino F. Lang A. Garvey J. Thompson M.A. Walker-Smith J.A. et al.A consistent pattern of minor immunodeficiency and subtle enteropathy in children with multiple food allergy.J Pediatr. 2003; 143: 40-48Abstract Full Text Full Text PDF Scopus (98) Google Scholar The retrospective analysis has drawn together clinical, histologic, and immunologic parameters to describe and distinguish subtypes on the basis of presentation. Immediate responders are compared with those whose reactions are delayed. The groups are not pure, however, because the vast majority (93%) of the immediate reactors also have delayed reactions. Immediate responders characteristically have “traditional” allergic reactions with urticaria, vomiting, or anaphylaxis associated with elevated serum IgE, and positive skin prick and radioallergosorbent test (RAST) to the offending foods. They often pose little difficulty in diagnosis from history, although the dramatic immediate reactions of food protein-induced enterocolitis syndrome may confuse the casual listener, as victims are typically skin test-negative to the offending protein because the process is cell-mediated. An excellent analysis and description of food protein-induced enterocolitis syndrome has been published recently and is essential reading for pediatricians.2.Nowak-Wegrzyn A. Sampson H.A. Wood R.A. Sicherer S.H. Food protein-induced enterocolitis syndrome caused by solid food proteins.Pediatrics. 2003; 111: 829-835Crossref PubMed Scopus (295) Google Scholar Delayed reactions to food proteins are more complicated to diagnose. Commonly available allergy testing with skin prick or RAST will most likely fail to identify the culprit. In the current series, only 27% of the delayed responders had positive skin tests. However, clinical suspicion that an immunologic reaction might underlie the symptom is increased by the frequent association (68%) with other atopic symptoms such as eczema, asthma, and hay fever. It is clear that the perception that “if your skin tests are negative then you're not allergic to it” needs either to be abandoned or the terminology changed. Symptoms may point generally to food, but determining which food(s) is difficult when only delayed reactions occur and standard skin prick testing is negative. Skin patch testing—prolonged application of food to the skin surface—has recently been suggested as an additional means of detecting responses to foods in patients with allergic eosinophilic esophagitis, another recently described disorder that sometimes develops as a consequence of delayed reactions to food.3.Spergel J.M. Beausoleil J.L. Mascarenhas M. Liacouras C.A. The use of skin prick tests and patch tests to identify causative foods in eosinophilic esophagitis.J Allergy Clin Immunol. 2002; 109: 363-368Abstract Full Text Full Text PDF PubMed Scopus (480) Google Scholar, 4.Kelly K.J. Lazenby J.A. Rowe P.C. Yardley J.H. Perman J.A. Sampson H.A. Eosinophilic esophagitis attributed to gastroesophageal reflux: improvement with an amino acid-based formula.Gastroenterology. 1995; 109: 1503-1512Abstract Full Text PDF PubMed Scopus (899) Google Scholar In the absence of perfect testing, double-blind placebo-controlled food challenges (DBPCFC) are necessary for confirmation of a relationship between the symptom and ingestion of the food. For delayed reactions, DBPCFC are reliable when clearly positive or negative, but when the symptoms are non-specific (sleep disturbance in a toddler, for example) they are fraught with the vagaries of the subjectivity beast. Because they are time-consuming and produce illness when a reaction develops, the challenge for us is to develop accurate, reproducible, noninvasive means for identifying the offending foods. At the same time, identifying the immune defect that permits the development of hypersensitivity to food antigens is essential. In the current study, careful examination of other immune markers including IgG subclass levels and quantitation of lymphocyte subpopulations revealed subtle deviation from normal. Although neither causal nor diagnostic in and of themselves, these findings lend further credence to the notion that these children have underlying immune dysregulation. Failed induction of oral tolerance leading to sensitization against multiple food antigens and the repeated or prolonged infections reported in nearly one third of these children may be sequelae of a common pathophysiologic process. Until we understand oral tolerance and can induce it at will with probiotics or other provocative signaling at the appropriate time in immune development, these children will continue to mount inappropriate responses to otherwise harmless dietary components.5.Murch S.H. Toll of allergy reduced by probiotics.Lancet. 2001; 357: 1057-1059Abstract Full Text Full Text PDF PubMed Scopus (100) Google Scholar The question as to why there seems to be an increasing population of children who fail to develop oral tolerance remains unanswered. It should be of particular concern to gastroenterologists and pathologists alike that mild enteropathy resulting from immune reactions to food was only discovered on morphometric analysis of duodenal biopsies, many after a provisional diagnosis of “normal” had been entertained. Mildly altered crypt:villous ratio and patchy infiltration of the lamina propria with lymphocytes or eosinophils are subject to considerable subjective interpretation and debate under the best of circumstances, as endoscopic biopsies are small and difficult to orient precisely for cross-sectional analysis. In addition, the definition of normal is a moving target, as our understanding and threshold for recognizing the histologic impact of the mucosal immune response to dietary antigens change. The patchy nature of the inflammatory process demands that multiple biopsy specimens be taken to assure adequate representation. The need to include an immunologic reaction to food in the differential diagnosis of common symptoms, irrespective of severity, is ever more important. Many of the children in the study developed symptoms and presented in infancy, but referral for definitive diagnosis was not made until years later in some. The frustration of families in those situations should not be underestimated. Months and years of delay, denial, and barking up the wrong tree take an enormous emotional toll on the family while perpetuating the damage to the baby. It might be easy to see how a parent insistent on additional testing for fairly nonspecific symptoms might eventually be accused of Munchausen's syndrome by proxy, but the fact that 5 of 77 families in this cohort were so reproached despite other objective and suggestive findings in their children is shameful. At the same time, it is not surprising that these families fail to successfully navigate the subspecialty labyrinth. The gastroenterologist did the endoscopy and didn't see much, the biopsy results were underwhelming to the pathologist, and the allergist said the child wasn't allergic because the skin tests were negative. Random elimination of foods didn't help. The child is still sick. Now what? Of course, there is no simple solution. When all indications point to food allergy, an elemental diet trial becomes both diagnostic and therapeutic when successfully completed, which is no small task after infancy. For the purposes of the current study, multiple food allergy was diagnosed if the child was hypersensitive to two or more foods. At the severe end of the spectrum, 10 children required prolonged exclusive use of an amino acid-based formula. These children are perceived as “allergic to everything.” Although they have not been challenged with literally “everything,” they have reacted to everything they have tried. Continuing food challenges in the face of repeated failure is emotionally taxing and, if not carefully done, commits the child to perpetual illness during the failed search for something to eat. It is essential to recognize these cases and suspend food challenges until such time as optimal health is restored, and until the child and parent are ready to give it another go. Parents uniformly want to know the natural history. Will my child “outgrow” this? Will my child ever be able to eat? From the article it is clear that many young children will develop oral tolerance, but it is equally clear that some do not, and that we currently do not have the ability to identify and classify those persons except in retrospect. For children who fail to develop significant oral tolerance, school age is particularly difficult. Food as nutrition, party fare, treat, snack, prize, reward, or commercial advertisement is everywhere. For the child whose backpack contains an infusion pump and formula instead of books, food outside the parents' observation represents a challenge, potential threat, or opportunity to cheat. The presence of food in the classroom magnifies the difference between the hypersensitive child and those who eat, and increases the psychologic impact of the disorder. Elemental formulas whose protein fraction is free amino acids offer legitimate therapy for children with multiple food allergies. However, there seems to be substantial inertia in the pediatric community to go beyond protein hydrolysate (ie, polypeptide-based) formulas. Confirming prior observations, nearly one third of the children in the current study, including many breast-fed infants, did not tolerate hydrolysate formulas.6.Vanderhoof J.A. Murray N.D. Kaufman S.S. Mack D.R. Antonson D.L. Corkins M.R. et al.Intolerance to protein hydrolysate formulas: an under recognized cause of gastrointestinal symptoms in infants.J Pediatr. 1997; 131: 741-744Abstract Full Text Full Text PDF PubMed Scopus (145) Google Scholar The use of hydrolysates, although they are less costly and more easily available, must be abandoned as quickly as cow's milk-based formula if symptoms aren't promptly controlled. The impact and implications of prolonged use of amino acid-based formula on the children and families was beyond the scope of the manuscript, but deserves attention. Exclusive use of formula from infancy forestalls normal acquisition of oromotor skills, such that when food trials are proposed, the child may be developmentally unprepared to accept the new food, irrespective of its immunologic importance. Gagging, vomiting, and overt refusal confound the interpretation of immune tolerance. In addition, with prolonged use, many children simply refuse to drink enough formula to meet their nutritional requirements and thus require tube feeding. The cost of elemental formulas is prohibitive for most families. The constant battle to obtain insurance compensation over insipid arguments posed by companies prepared only to preserve their fiscal security has forced families to engage media attention or legal representation, and has pushed many state legislatures to compel coverage. As evidence for the increasing problem of food protein hypersensitivity is published, perhaps the mainstream insurance community will withdraw its head from its bottom (line), formally recognize the importance of these conditions, and remove the barriers to immediate coverage. On a final note, the term “multiple food allergies” seems somehow inadequate to describe all the affected patients along the spectrum of the disorder. It is intellectual impotence to name things for what they are not (eg, “non-IgE mediated food allergies”), but until the true nature of the defect is understood, it may have to do. In keeping with current times, perhaps we could just call it “the Mother of All Food Allergies” until then.