Implications of Eosinophilia in the Normal Duodenal Biopsy – An Association with Allergy and Functional Dyspepsia

M. M. Walker; S. S. Salehian; C. E. Murray; A. Rajendran; J. M. Hoare; R. Negus; N. Powell; N. J. Talley

Disclosures

Aliment Pharmacol Ther. 2010;31(11):1229-1236. 

In This Article

Abstract and Introduction

Abstract

Background Allergy and functional gastrointestinal disorders have been associated with eosinophilia in duodenal mucosa.
Aim To assess the prevalence of eosinophilia in duodenal biopsies of patients attending for oesophogastroduodenoscopy and delineate associated clinical conditions.
Methods A total of 155 patients (mean age 55 years, 59% women) with normal duodenal biopsies were randomly selected for audit from histopathology files. Eosinophil counts in five high power fields (HPFs) were assessed. Records were analysed for symptoms, diagnosis and medications; patients were divided into five groups based on upper gastrointestinal (UGI) symptom profiles, including a control group of those without predominant UGI symptoms. The prevalence of duodenal eosinophilia (defined as >22/5HPFs a priori) was calculated.
Results In the control group, the mean duodenal eosinophil count was 15/5HPFs; prevalence of duodenal eosinophilia was 22.5%. In postprandial distress syndrome (PDS), both mean eosinophil counts (20.2/5HPF, P < 0.04) and prevalence of duodenal eosinophilia (47.3%, P < 0.04) were significantly higher. Duodenal eosinophilia was significantly associated with allergy (OR 5.04, 95% CI 2.12–11.95, P < 0.001). There was no association with irritable bowel syndrome or medications.
Conclusions Subtle duodenal eosinophilia is relatively common in routine oesophogastroduodenoscopy and previously overlooked; it is associated with allergy and may indicate a hypersensitivity mechanism in some patients with PDS including early satiety.

Introduction

The eosinophil is a characteristic bone marrow derived circulating granulocyte with diverse functions; it hosts an array of effector mechanisms important in normal physiology throughout the gastrointestinal (GI) tract of healthy subjects.[1] The only part of the GI tract normally free of eosinophils is the squamous epithelium of the oesophagus.[1] The normal function of the eosinophil in host defence and immune regulation is carried out via effector secretory granules, which effect antigen presentation, cytokine release, mast cell activation and immune tolerance.[2] Established in their position in host defence against helminths,[3,4] eosinophils also play an important role in combating bacterial and viral infections.[1,5] Gastric eosinophilia occurs in Helicobacter pylori infection.[5] Dysregulation of eosinophils also occurs in allergic disease, parasite infestation, tumours, drug reactions and hypersensitivity.[1]

Small bowel biopsies from patients with asthma and allergic rhinitis show features in common with the inflammatory reaction observed in the airways, with accumulation of eosinophils.[6] Gastrointestinal symptoms are also significantly more common in patients with asthma and allergic rhinitis.[7] Recently, eosinophils have been implicated in contributing to functional gastrointestinal disorders (FGIDs).[8,9] The FGIDs, including irritable bowel syndrome (IBS) and functional dyspepsia (FD) are defined by chronic abdominal symptoms not associated with known structural or biochemical pathology.[5,9,10] Definitive criteria for FGIDs are arguably problematic because of the wide spectrum of manifestations and as a result, FGIDs are grouped by symptoms and there is a considerable overlap of these disorders based on current classification schemes.[11,12]

At endoscopy, duodenal biopsies are usually taken to exclude coeliac disease, but recent studies[6–9] suggest that duodenal eosinophilia may be a marker for atopy, allergy and possibly functional dyspepsia, but not irritable bowel syndrome (IBS).[8] Eosinophils are easily visualized on sections stained by haematoxylin and eosin (Figure 1) and therefore can be counted by histopathologists without the need for special stains.

Figure 1.

The characteristic morphological features of eosin uptake in the cytoplasm and bi-lobed nuclei identify eosinophils in H&E stained sections (original magnification ×100).

The aim of this study was to audit duodenal biopsies previously reported as normal to assess eosinophil counts and correlate these with review of the clinical records, to ascertain if these cells may be a biomarker for disease states.

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