Electron microscopy elucidates eosinophil degranulation patterns in patients with eosinophilic esophagitis.

Abstract

BACKGROUND:

In patients with eosinophilic esophagitis (EoE), eosinophils accumulate and release granule proteins onto esophageal epithelium. However, little is understood about the mechanism of eosinophil degranulation.

OBJECTIVE:

To determine and quantify eosinophil degranulation patterns, we studied esophageal biopsy specimens from both the proximal and distal esophagi of 9 randomly selected patients with EoE.

METHODS:

The specimens were fixed in glutaraldehyde, embedded, sectioned, and imaged by means of transmission electron microscopy. Eosinophils and their granules were identified by their distinctive morphology, and all eosinophils and granules were imaged. A total of 1672 images from 18 esophageal specimens were evaluated and graded. Eosinophils were categorized based on membrane integrity and by cytoplasmic vesiculation as evidence of piecemeal degranulation. Granules were categorized based on reversal of staining (eosinophil granule core lightening) and localization within and outside the cells.

RESULTS:

The results revealed that greater than 98% of eosinophils infiltrating the esophagus in patients with EoE demonstrate morphologic abnormalities ranging from granule changes with reversal of staining to marked cytoplasmic vesiculation to loss of cellular membrane integrity with cytolytic disruption and release of intact membrane-bound granules into the tissues. Approximately 81% of eosinophils showed membrane disruption. Extracellular granules were abundant in at least 70% of the images, and approximately 50% of these granules showed reversal of staining. On the basis of the prominence of tubulovesicular development, piecemeal degranulation appears closely related to the other morphologic changes seen in patients with EoE.

CONCLUSION:

These findings reveal that eosinophils in esophageal biopsy specimens from patients with EoE are abnormal, with greater than 80% showing cytolysis, and therefore that evaluation by means of light microscopy after hematoxylin and eosin staining might not accurately reflect eosinophil involvement.

• Authors: Hedieh Saffari, Laura H Hoffman, Kathryn A Peterson, John C Fang, Kristin M Leiferman, Leonard F Pease 3rd, Gerald J Gleich
• Journal: The Journal of allergy and clinical immunology (J Allergy Clin Immunol) Vol. 133 Issue 6 Pg. 1728-34.e1 (Jun 2014) ISSN: 1097-6825 [Electronic] United States
• PMID: 24439077 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
• Copyright: Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Topics

• Adult
• Cell Degranulation (immunology)
• Eosinophilic Esophagitis (immunology)
• Eosinophils (immunology, ultrastructure)
• Female
• Humans
• Male
• Microscopy, Electron
• Middle Aged
• Young Adult