Electron microscopy elucidates eosinophil degranulation patterns in patients with eosinophilic esophagitis

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...

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Bibliographic Details
Published in:Journal of allergy and clinical immunology 2014-06, Vol.133 (6), p.1728-1734.e1
Main Authors: Saffari, Hedieh, PhD, Hoffman, Laura H., BSc, Peterson, Kathryn A., MD, Fang, John C., MD, Leiferman, Kristin M., MD, Pease, Leonard F., PhD, Gleich, Gerald J., MD
Format: Article
Language:English
Subjects:
activation
Adult
Allergy and Immunology
Biological and medical sciences
Biopsy
Cell Degranulation - immunology
cytolysis
electron microscopy
Eosinophilic esophagitis
Eosinophilic Esophagitis - immunology
eosinophils
Eosinophils - immunology
Eosinophils - ultrastructure
Esophagus
Female
Fundamental and applied biological sciences. Psychology
Fundamental immunology
Gastroenterology. Liver. Pancreas. Abdomen
Humans
Immunopathology
Male
Medical sciences
Microscopy, Electron
Middle Aged
Other diseases. Semiology
Patients
piecemeal degranulation
Proteins
Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis
Studies
Young Adult
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Summary: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.
ISSN:0091-6749
1097-6825
DOI:10.1016/j.jaci.2013.11.024