Related Experiment Video
Updated: May 21, 2026
Direct Observation of Phagocytosis and NET-formation by Neutrophils in Infected Lungs using 2-photon Microscopy
Published on: June 2, 2011
Improving the detection of fungi in eosinophilic mucin: seeing what we could not see before
Canting Guo1, Saied Ghadersohi, Gail M Kephart
1University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, NY, USA. cantingg@buffalo.edu
Objective:
To investigate the improvement in histologic detection of fungi with Gomori methenamine silver (GMS) stain by trypsin predigestion in the mucus of patients with chronic rhinosinusitis (CRS).
Study Design:
Prospective, single group, descriptive analysis.
Setting:
Multi-institutional.
Subjects And Methods:
Thirty-four sinus specimens from 12 surgical patients with CRS were stained with hematoxylin and eosin, GMS stain, GMS with trypsin digestion, immunofluorescence stains for chitinase, and anti-Alternaria. All patients received skin testing, total IgE serology, and radioallergosorbent tests (RAST) for 23 fungal-specific IgE antibodies.
Results:
The conventional GMS stain detected fungi in only 9 of 34 (27%) specimens. Predigesting the specimen with trypsin dramatically improved the visualization of fungi (31/34, 91%). The chitinase immunofluorescence visualized fungi in 32 of 34 (94%), and anti-Alternaria visualized 33 of 34 specimens (97%). Only 8 of 12 (75%) patients had detectable allergies.
Conclusions:
This report describes a simple modification of the conventional GMS stain that can significantly improve the visualization of fungi on histology and explains the lack of detection in previous studies. These novel, more sensitive histologic methods reveal the presence of fungi within the eosinophilic mucin in allergic and also nonallergic CRS patients, further questioning a crucial role of an IgE-mediated pathophysiology.
Insights
Trypsin predigestion significantly enhances fungal detection in chronic rhinosinusitis (CRS) mucus using Gomori methenamine silver (GMS) stain. This improved histologic method reveals fungi in most CRS patients, challenging IgE-mediated allergy roles.
Area of Science:
- Medical Mycology
- Histopathology
- Immunology
Background:
- Chronic rhinosinusitis (CRS) is a complex inflammatory condition.
- Accurate fungal detection in CRS is crucial for understanding disease mechanisms.
- Conventional Gomori methenamine silver (GMS) stain has limitations in visualizing fungi in sinus mucus.
Purpose of the Study:
- To evaluate the efficacy of trypsin predigestion in improving fungal detection using GMS stain.
- To compare trypsin-digested GMS with other fungal detection methods.
- To investigate the presence of fungi in allergic and nonallergic CRS patients.
Main Methods:
- Prospective, multi-institutional descriptive analysis of 34 sinus specimens from 12 CRS patients.
- Histologic staining included hematoxylin and eosin, conventional GMS, trypsin-digested GMS, chitinase immunofluorescence, and anti-Alternaria.
- Patients underwent skin testing and serologic tests for fungal-specific IgE antibodies.
Main Results:
- Conventional GMS detected fungi in 27% of specimens.
- Trypsin predigestion increased fungal detection to 91%.
- Chitinase and anti-Alternaria stains showed high detection rates (94% and 97%, respectively).
- Only 75% of patients had detectable fungal allergies.
Conclusions:
- Trypsin predigestion is a simple, effective modification to enhance GMS staining for fungal detection in CRS.
- Novel, sensitive histologic methods reveal fungi in eosinophilic mucin of both allergic and nonallergic CRS.
- Findings question a central role for IgE-mediated pathophysiology in CRS fungal presence.
