Diagnosis of Pediatric Non-Esophageal Eosinophilic Gastrointestinal Disorders by Eosinophil Peroxidase Immunohistochemistry.

BACKGROUND: Diagnosis of non-esophageal eosinophilic gastrointestinal disorders requires quantification of tissue eosinophils. Our objective was to evaluate eosinophil peroxidase (EPX) immunohistochemistry (IHC) as a method for histologic diagnosis of eosinophilic gastritis (EG) and eosinophilic duodenitis (EoD). METHODS: We performed a retrospective analysis of biopsies from pediatric EG/EoD cases and controls. Subjects with EG or EoD had ≥30 eosinophils per high power field (eos/hpf) in ≥5 hpf in the stomach and/or ≥3 hpf in the duodenum, respectively. Controls had no histopathologic diagnosis recorded. Tissue eosinophil counts were assessed by hematoxylin & eosin stains. EPX stains were assessed using a unique histopathologic scoring system. Slides were digitized and EPX+ staining area/mm2 was quantified by image analysis. RESULTS: Twenty-six EG/EoD cases and 40 controls were analyzed. EPX scores and EPX/mm2 levels were markedly elevated in EG/EoD (p ≤ 0.0001). Eosinophil density (eos/mm2) correlated strongly with EPX scores and EPX/mm2 levels in the stomach (r ≥ 0.77) and moderately with EPX scores and EPX/mm2 levels in the duodenum (r ≥ 0.52); (p < 0.0001). EPX quantification identified EG/EoD subjects with high diagnostic accuracy (EPX score: AUC = 1 for EG and EoD; EPX/mm2: AUC = 0.98 (95%CI 0.96-1) for EG, AUC = 0.91 (95%CI 0.81-1) for EoD). CONCLUSION: EPX-based assessment of eosinophilic inflammation may facilitate automated histologic diagnosis.

Esophageal human ß-defensin expression in eosinophilic esophagitis.

BACKGROUND: Defensins are antimicrobial peptides expressed on mucosal surfaces that contribute to maintaining intestinal homeostasis by providing innate defense mechanisms for the epithelia. Defensin expression is altered in a number of diseases that affect mucosal surfaces, such as atopic dermatitis, allergic rhinitis, and inflammatory bowel disease. Similar to atopic dermatitis, eosinophilic esophagitis (EoE) is a chronic disease in which the squamous epithelial surface is affected by a similar TH2 microenvironment and eosinophil-predominant inflammation. Therefore, we hypothesized that defensin expression would be decreased in EoE. METHODS: To address this, we measured defensin expression in vitro in cell lines derived from patients with EoE (EoE1-T) or gastroesophageal reflux disease (GERD) (NES-G4T cells) and ex vivo in esophageal mucosal biopsy samples from children with EoE or GERD and control children without esophageal disease. RESULTS: Interleukin-5 induced a decrease in human ß-defensin (hBD) -1 and hBD3 expression in EoE1-T but not in NES-G4T cells. Compared with esophageal biopsy specimens from GERD and control children, specimens from EoE pediatric patients revealed a significant decrease in mRNA and protein expression for hBD1 and hBD3. CONCLUSION: Diminished expression of hBD1 and hBD3 may make the esophageal epithelium more susceptible to the development and/or perpetuation of EoE.

CT imaging features of eosinophilic colitis in children.

BACKGROUND: Eosinophilic colitis (EC) is a gastrointestinal disease of undetermined etiology whose clinical features overlap with those of the inflammatory bowel diseases. To the best of our knowledge, the CT imaging features of EC have not been described in children. OBJECTIVE: To report and analyze the clinical, imaging and histological findings in seven children with EC. MATERIALS AND METHODS: Children with EC were identified in a pediatric pathology database, and those with CT imaging within 2 months of diagnosis were included, totaling seven children. Clinical, imaging and pathological features were reviewed and analyzed. RESULTS: The most common presenting symptoms were abdominal pain, bloody diarrhea and rectal bleeding. EC was characterized as a dense and predominantly eosinophilic inflammatory infiltrate in the lamina propria or epithelium without granulomas. CT scans were abnormal in six children (86%), demonstrating colonic wall thickening, predominantly cecal, in five (71%), mild to moderate terminal ileal thickening in two (29%), and pneumatosis in one (14%). Right colonic involvement was greater than terminal ileal involvement. CONCLUSION: CT imaging findings in children with EC include right colonic wall thickening of variable extent downstream and absent or mild involvement of the terminal ileum. EC should be considered in the differential diagnosis in children presenting with abdominal pain and bloody diarrhea.

Effect of proton pump inhibitor on esophageal eosinophilia.

OBJECTIVE: Differentiation between the common etiologies of dense esophageal eosinophilia such as gastroesophageal reflux disease (GERD) and eosinophilic esophagitis can be difficult. We hypothesized that histologic features may provide diagnostic clues concerning the etiology of esophageal eosinophilia. METHODS: : We performed a retrospective chart review of 204 children with the diagnosis of esophagitis characterized by ≥ 15 eosinophils (eos) per high-power field (HPF) in at least 1 biopsy. We then restricted our analysis to subjects who had received at least 8 weeks of only proton pump inhibitors (PPIs) followed by endoscopy and who had a clinicopathologic response to this treatment. Symptoms, endoscopic findings, and pathologic descriptions were reviewed and an eosinophil peroxidase (EPX) index was determined to assess for degranulation/eosinophil activation. RESULTS: Of the 204 identified charts, 7 subjects identified met the inclusion criteria. Five of these 7 patients showed a clinicopathologic response to PPIs after their follow-up endoscopy, (mean peak eosinophil count: 92 vs 5 eos/HPF, and EPX index: 39.2 vs 14.6, pre- and posttreatment, respectively). Two patients experienced initial resolution of symptoms and esophageal eosinophilia with PPI therapy; however, within 17-23 months they redeveloped symptoms and esophageal eosinophilia while receiving PPI therapy at the time of a third endoscopy (mean peak eosinophil count: 40 vs 11 vs 36 eos/HPF, and EPX index: 44 vs 21 vs 36.5, pre-, post- and posttreatment, respectively). No clinicopathologic features or degranulation patterns differentiated subjects with GERD/PPI responsive esophageal eosinophilia from those who had transient response to PPI treatment. CONCLUSIONS: No clinicopathologic features differentiated subjects who responded to PPI treatment. PPI treatment can be helpful to exclude GERD and PPI responsive esophageal eosinophilia but long-term follow-up is critical in the management of esophagitis.

The oesophageal string test: a novel, minimally invasive method measures mucosal inflammation in eosinophilic oesophagitis.

OBJECTIVE: Eosinophil predominant inflammation characterises histological features of eosinophilic oesophagitis (EoE). Endoscopy with biopsy is currently the only method to assess oesophageal mucosal inflammation in EoE. We hypothesised that measurements of luminal eosinophil-derived proteins would correlate with oesophageal mucosal inflammation in children with EoE. DESIGN: The Enterotest diagnostic device was used to develop an oesophageal string test (EST) as a minimally invasive clinical device. EST samples and oesophageal mucosal biopsies were obtained from children undergoing upper endoscopy for clinically defined indications. Eosinophil-derived proteins including eosinophil secondary granule proteins (major basic protein-1, eosinophil-derived neurotoxin, eosinophil cationic protein, eosinophil peroxidase) and Charcot-Leyden crystal protein/galectin-10 were measured by ELISA in luminal effluents eluted from ESTs and extracts of mucosal biopsies. RESULTS: ESTs were performed in 41 children with active EoE (n=14), EoE in remission (n=8), gastro-oesophageal reflux disease (n=4) and controls with normal oesophagus (n=15). EST measurement of eosinophil-derived protein biomarkers significantly distinguished between children with active EoE, treated EoE in remission, gastro-oesophageal reflux disease and normal oesophagus. Levels of luminal eosinophil-derived proteins in EST samples significantly correlated with peak and mean oesophageal eosinophils/high power field (HPF), eosinophil peroxidase indices and levels of the same eosinophil-derived proteins in extracts of oesophageal biopsies. CONCLUSIONS: The presence of eosinophil-derived proteins in luminal secretions is reflective of mucosal inflammation in children with EoE. The EST is a novel, minimally invasive device for measuring oesophageal eosinophilic inflammation in children with EoE.

Novel device to sample the esophageal microbiome--the esophageal string test.

A growing number of studies implicate the microbiome in the pathogenesis of intestinal inflammation. Previous work has shown that adults with esophagitis related to gastroesophageal reflux disease have altered esophageal microbiota compared to those who do not have esophagitis. In these studies, sampling of the esophageal microbiome was accomplished by isolating DNA from esophageal biopsies obtained at the time of upper endoscopy. The aim of the current study was to identify the esophageal microbiome in pediatric individuals with normal esophageal mucosa using a minimally invasive, capsule-based string technology, the Enterotest™. We used the proximal segment of the Enterotest string to sample the esophagus, and term this the "Esophageal String Test" (EST). We hypothesized that the less invasive EST would capture mucosal adherent bacteria present in the esophagus in a similar fashion as mucosal biopsy. EST samples and mucosal biopsies were collected from children with no esophageal inflammation (n = 15) and their microbiome composition determined by 16S rRNA gene sequencing. Microbiota from esophageal biopsies and ESTs produced nearly identical profiles of bacterial genera and were different from the bacterial contents of samples collected from the nasal and oral cavity. We conclude that the minimally invasive EST can serve as a useful device for study of the esophageal microbiome.