Educational clinical case series in pediatric allergy and immunology

Toward uniformity in the diagnosis of eosinophilic esophagitis (EoE): the effect of guidelines on variability of diagnostic criteria for EoE

OBJECTIVES

Recent consensus guidelines for diagnosis of eosinophilic esophagitis (EoE) have been published. Whether these guidelines have standardized diagnostic criteria for EoE is unknown. We aimed to determine if the EoE guidelines had an impact on the diagnostic criteria reported in the EoE literature, and whether the previously observed variability in diagnostic criteria has become more uniform.

METHODS

Two investigators independently conducted a MEDLINE search from 1 January 2007 through 30 June 2010 for all publications reporting EoE in human subjects, and also searched the proceedings of the 2007-2010 American College of Gastroenterology and American Gastroenterological Association meetings, using a predefined search strategy. Data were extracted from all relevant publications.

RESULTS

Of the 799 publications identified, 149 original reports, 99 reviews, and 165 abstracts were included. In all, 32 original reports (21%) used diagnostic criteria consistent with each of the three components of the consensus guidelines. There was a significant increase when comparing original articles published after the release of the guidelines with those published earlier (31 vs. 6%, P<0.001). The proportion of original articles using 15 eosinophils per high-power field (eos/hpf) as a histological cut-point increased significantly (P=0.001). There was still substantial variability in biopsy protocols and eosinophil count methodology. The majority of original articles did not report microscope high-power field (HPF) area.

CONCLUSIONS

The proportion of original reports with diagnostic criteria consistent with the consensus guidelines has increased significantly. However, the majority of articles still did not conform to all three of the criteria in the guidelines, and biopsy and eosinophil count protocols continue to demonstrate significant variability. Standardization of biopsy and eosinophil count protocols is needed.

A shift in the clinical spectrum of eosinophilic gastroenteritis toward the mucosal disease type

BACKGROUND & AIMS

Eosinophilic gastroenteritis (EG) is a rare disorder characterized by eosinophilic infiltration of the gastrointestinal (GI) tract. Despite the increasing prevalence of eosinophilic GI disorders, the epidemiology of EG has not been well studied. We evaluated the clinical spectrum of EG.

METHODS

We reviewed data from patients diagnosed with EG, allergic gastroenteropathy, or eosinophilia and referred to gastroenterologists from 1987 to 2007 (n = 59; 52 with mucosal, 3 with muscularis, and 4 with subserosal disease). The study included subjects diagnosed with EG and those with a history that suggested EG, defined by GI symptoms; eosinophilic infiltration of the GI tract, eosinophilic ascites, or characteristic radiographic findings with eosinophilia; and no parasitic or extraintestinal disease. Findings were compared with those from patients with unexplained GI symptoms and peripheral eosinophilia (n = 11).

RESULTS

Associations between clinical variables and EG subgroups did not differ between patients with EG and peripheral eosinophilia. Fifty percent of patients with EG who underwent food allergy testing had a positive test result; only 32% of those with EG who underwent radiographic imaging had positive test results. Patients with EG received steroid therapy; 75% with mucosal, 67% with muscle, and 100% with subserosal disease received prednisone. Eighty-eight percent of patients who received only steroids (mean follow-up period, 7 mo) and 94% of patients who received steroids in combination with another therapy (mean follow-up period, 4 mo) had improved or resolved disease.

CONCLUSIONS

Unlike eosinophilic esophagitis, EG is rare. Results from this large study suggest that EG disease type has shifted toward that of the mucosal layer.

The role of mast cells in eosinophilic esophagitis

Eosinophilic esophagitis (EE) is a chronic inflammatory disease of the esophagus which is characterized by the presence of dense infiltrate of eosinophilic leukocytes restricted to this organ mucosa. Accumulating published evidence suggests a strong role of mast cells in the inflammatory infiltrate in the physiopathology of EE. We have reviewed published articles with relevant information about the presence and possible role of mast cells in EE. Although mast cells have been studied indirectly in EE, reported data allow us to confirm that the number of mast cells infiltrating the esophageal epithelium in adult and child patients with EE is higher with respect to the normal state and in gastroesophageal reflux disease. Mast cells linked to IgE, which are not found in other conditions, have been identified in EE. Despite that fact, an anaphylactic reaction history after exposure to allergens is not common in these patients. Therefore, the mast cells' function in EE could be dependent on T lymphocytes, as suggested by a mast cell gene expression analysis. Bi-directional crosstalk is established between mast cells and eosinophils, hence establishing interesting hypotheses regarding their relationship to EE physiopathology. Mast cells' function as an immune response leader seems to substitute for their effector functions in EE, while at the same time opening new research pathways for consideration of these cells as a therapeutic target in EE. However, the inefficiency of therapies that inhibit mast cell functions while they are effective in other respiratory tract diseases results in the need for specific studies to identify the real function of such complex cells in the physiopathology of EE. There is indirect proof of the role of mast cells in EE, while many doubts exist about their activation mechanism, which does not seem to be IgE-mediated. Specific approach studies are needed to clarify the function of these cells in the physiopathology of EE, which could be a possible therapeutic target.

Allergic gastrointestinal motility disorders in infancy and early childhood

Gastro-oesophageal reflux disease, constipation and colic are among the most common disorders in infancy and early childhood. In at least a subset of infants with these functional disorders, improvement after dietary elimination of specific food proteins has been demonstrated. Gastrointestinal food allergy should therefore be considered in the differential diagnosis of infants presenting with persistent regurgitation, constipation or irritable behaviour, particularly if conventional treatment has not been beneficial. The diagnosis of food protein-induced gastrointestinal motility disorders is hampered by the absence of specific clinical features or useful laboratory markers. Gastrointestinal biopsies before commencing a hypoallergenic diet may provide the most important diagnostic clues. Early recognition is essential for the optimal management of these patients to prevent nutritional sequelae or aversive feeding behaviours. Treatment relies on hypoallergenic formulae, as well as maternal elimination diets in breast-fed infants. Further research is required to better define the pathological mechanisms and diagnostic markers of paediatric allergic gastrointestinal motility disorders. The following article will present three instructive cases followed by discussion of the clinical presentation, diagnosis, treatment and natural history of food allergic motility disorders in infancy and early childhood.

Eosinophilic gastroenteritis

Eosinophilic gastroenteritis is an infrequently diagnosed condition that is characterized by prominent eosinophilic infiltration of the stomach or small intestine, generally localized to one level of the intestinal wall; the variable organ locus and wall depth produce heterogeneous clinical presentations. A strong association with atopy is present in most cases, supported by circumstantial evidence and the demonstration of Th-2 proinflammatory cytokine profiles in animal studies. A high degree of suspicion is required to establish the diagnosis, which must be based on intense gastrointestinal eosinophilia. Management is directed toward removal of offending allergens and use of anti-inflammatory agents. Novel and emerging treatments on the horizon are biologic therapies and selective anti-eosinophil agents.