EoE should be diagnosed when there are symptoms of esophageal dysfunction and at least 15 eosinophils per high-power field (or approximately 60 eosinophils per mm) on esophageal biopsy and after a comprehensive assessment of non-EoE disorders that could cause or potentially contribute to esophageal eosinophilia. The evidence suggests that PPIs are better classified as a treatment for esophageal eosinophilia that may be due to EoE than as a diagnostic criterion, and we have developed updated consensus criteria for EoE that reflect this change.

Children with Down syndrome have a 10-20-fold elevated risk of developing leukemia, particularly acute megakaryoblastic leukemia (AMKL). While a subset of pediatric AMKLs is associated with the 1;22 translocation and expression of a mutant fusion protein, the genetic alterations that promote Down syndrome-related AMKL (DS-AMKL) have remained elusive. Here we show that leukemic cells from every individual with DS-AMKL that we examined contain mutations in GATA1, encoding the essential hematopoietic transcription factor GATA1 (GATA binding protein 1 or globin transcription factor 1). Each mutation results in the introduction of a premature stop codon in the gene sequence that encodes the amino-terminal activation domain. These mutations prevent synthesis of full-length GATA1, but not synthesis of a shorter variant that is initiated downstream. We show that the shorter GATA1 protein, which lacks the N-terminal activation domain, binds DNA and interacts with its essential cofactor Friend of GATA1 (FOG1; encoded by ZFPM1) to the same extent as does full-length GATA1, but has a reduced transactivation potential. Although some reports suggest that the activation domain is dispensable in cell-culture models of hematopoiesis, one study has shown that it is required for normal development in vivo. Together, these findings indicate that loss of wildtype GATA1 constitutes one step in the pathogenesis of AMKL in Down syndrome.

In a prospective study of children with EoE, 8 weeks of 4-food elimination diet induced clinical, endoscopic, and histologic remission in more than 60% of children with EoE. Although less restrictive than 6-food elimination diet, 4-food elimination diet was nearly as effective, and can be recommended as a treatment for children with EoE.

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BACKGROUND & AIMS The endoscopic reference score (EREFS) is used to determine severity of 5 endoscopic findings: edema, rings, exudates, furrows, and strictures. Little is known about the relationship between EREFSs and histologic markers of disease activity in children with eosinophilic esophagitis (EoE). We aimed to determine whether the EREFS can be used to identify children with EoE and how it changes with treatment. METHODS We performed a prospective study of consecutive children (ages 2–17 years) undergoing diagnostic or post-treatment endoscopy scored real-time with EREFS from December 2012 through 2016. Findings from 192 diagnostic endoscopies and 229 post-treatment endoscopies were evaluated, from 371 children. Incident EoE cases were diagnosed based on 2011 consensus guidelines. Patients were treated with either elimination diet or topical steroids. Subjects who underwent endoscopy for symptoms of esophageal dysfunction but had normal esophageal findings from histology analysis were used as controls. EREFS and receiver operating characteristic curves were determined for incident EoE cases (n = 77) vs controls (n = 115), patients with active EoE (n = 101) vs inactive EoE after treatment (n = 128), and paired pre- and post-treatment cases of EoE (n = 85). Component and composite scores were correlated with eosinophilia. RESULTS Visual detection of more than 1 esophageal abnormality during the diagnostic endoscopy identified children with EoE with 89.6% sensitivity and 87.9% specificity. EREFS correlated with peak level of eosinophilia (P < .001) at all esophageal levels. Children who responded to therapy had mean EREFSs of 0.5 compared to 2.4 in non-responders. In comparing pre-treatment vs post-treatment data from 85 patients, we found a significant reduction in the composite EREFS (from 2.4 to 0.7) (P < .001) among patients who responded to treatment; 92% of responders had a reduced EREFSs after treatment. EREFSs identified children with EoE with an area under the curve value (AUC) of 0.93. EREFSs identified children with active EoE following treatment with an AUC of 0.81 before treatment and an AUC of 0.79 after treatment. CONCLUSIONS In a prospective study of children undergoing diagnostic or post-treatment endoscopy, we found the EREFS to accurately identify those with EoE. Children who responded to therapy had lower EREFS scores than non-responders. EREFSs can be used to measure outcomes of pediatric patients, in conjunction with histology findings, and assess treatments for children with EoE.

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Ulcerative colitis (UC) patients exhibit elevated histamine, but how histamine exacerbates disease is unclear since targeting histamine 1 receptor (H1R) or H2R is clinically ineffective. We hypothesized that histamine functioned instead through the other colon-expressed histamine receptor, H4R. In humans, UC patient biopsies exhibited increased H4R RNA and protein expression over control tissue, and immunohistochemistry showed that H4R was in proximity to immunopathogenic myeloperoxidase-positive neutrophils. To characterize this association further, we employed both the oxazolone (Ox)- and dextran sulfate sodium (DSS)-induced experimental colitis mouse models and also found upregulated H4R expression. Mast cell (MC)-derived histamine and H4R drove experimental colitis, as H4R−/− mice had lower symptom scores, neutrophil-recruitment mediators (colonic IL-6, CXCL1, CXCL2), and mucosal neutrophil infiltration than wild-type (WT) mice, as did MC-deficient KitW-sh/W-sh mice reconstituted with histidine decarboxylase–deficient (HDC−/−) bone marrow–derived MCs compared to WT-reconstituted mice; adaptive responses remained intact. Furthermore, Rag2−/−×H4R−/− mice had reduced survival, exacerbated colitis, and increased bacterial translocation than Rag2−/− mice, revealing an innate protective anti-bacterial role for H4R. Taken together, colonic MC-derived histamine initiates granulocyte infiltration into the colonic mucosa through H4R, suggesting alternative therapeutic targets beyond adaptive immunity for UC.