2 MUCOSAL MAST CELLS DISTINGUISH ALLERGIC FROM GASTROESOPHAGEAL REFLUX-INDUCED ESOPHAGITIS.

Abstract

BACKGROUND: Recent evidence suggests that allergy may play a role in a subgroup of infants and children with characteristic eosinophilic esophagitis. These patients may be indistinguishable from patients with esophagitis caused by gastroesophageal reflux (GER), both clinically and histologically. We have previously demonstrated increased mucosal mast cells (MMC) in biopsies from patients with esophagitis vs controls, with a small subgroup showing a marked increase in MMC. AIM: To investigate MMC in patients with allergic eosinophilic esophagitis vs GER-induced esophagitis and controls. METHODS: Formalin-fixed paraffin embedded esophageal tissue was obtained from archival material. Eosinophils and MMC were stained with a dual mast cell/eosinophil stain (astra blue/vital new red); immunohistochemistry for MMC was performed with anti-mast cell tryptase antibodies (Dako) and an avidin-biotin detection system. Biopsies were reviewed blindly (A.R.); MMC and eosinophils per hpf were quantitated. Tryptase was more sensitive at detecting mast cells than dual staining therefore tryptase was used to enumerate MMC. Control patients had normal pH probes and were histologically normal. GER/esophagitis was defined by histologic inflammation with an abnormal pH probe (> 5% time with pH<4). Allergic esophagitis was defined by eosinophilic esophagitis with a normal pH probe or concomitant eosinophilic inflammation in antral or duodenal biopsies. RESULTS: MMC were significantly increased in allergic esophagitis vs GER induced esophagitis and control tissue. Eosinophils paralleled mast cell increases, with considerable overlap. Table CONCLUSION: The recognition of increased MMC allows one to distinguish allergy-induced from GER-induced esophagitis. Mast cell staining should be part of the histopathologic evaluation of select cases of esophagitis in infants and children when allergy is being considered.