Asthma, rhinitis, other respiratory diseases
Features of airway remodeling and eosinophilic inflammation in chronic rhinosinusitis: Is the histopathology similar to asthma?

https://doi.org/10.1016/j.jaci.2003.08.009Get rights and content

Abstract

Background

Asthma and chronic rhinosinusitis (CRS) coexist clinically in >50% of patients with CRS. Although epithelial damage and basement membrane thickening are well-known features of airway remodeling in asthma, they have not been described in CRS.

Objective

In this study, we tested the hypothesis that histopathologic features of asthma, namely, the chronic eosinophilic inflammation, epithelial damage, and basement membrane thickening of the airway mucosa, are also present in sinonasal specimens from patients with CRS.

Methods

We examined histologic specimens from 22 randomly selected patients with refractory CRS undergoing endoscopic sinus surgery and 4 healthy control subjects. The shedding of the epithelium and basement membrane thickening were evaluated by 3 independent observers' scores of hematoxylin-and-eosin staining. Eosinophilic inflammation was monitored with immunohistochemistry for eosinophil major basic protein. A novel, computerized method objectively analyzed confocal microscopic images of major basic protein immunofluorescence to determine areas with the least and most inflammation per specimen.

Results

Specimens from all patients with CRS (22/22) revealed epithelial damage (shedding) and basement membrane thickening. Strikingly heterogeneous eosinophilic inflammation, which did not differ between allergic and nonallergic patients, was detected in all patients with CRS and was absent in all healthy control subjects.

Conclusion

The histopathologic findings of asthma, namely, heterogeneous eosinophilic inflammation and features of airway remodeling, are also present in CRS. These findings, coupled with the common clinical coexistence of both diseases, suggest that the same pathologic disease process is manifest as CRS in the sinonasal tissue and as asthma in the lower airway.

Section snippets

Materials and methods

The Institutional Review Board of Mayo Clinic Rochester approved the study. The diagnostic guidelines established by the American Academy of Otorhinolaryngology—Head and Neck Surgery were met in each patient for the diagnosis of CRS.2 In addition, a coronal computed tomography scan was obtained in all patients demonstrating inflammatory mucosal thickening of >5 mm in >2 sinuses, consistent with CRS. Histologic specimens were processed from 22 randomly selected patients with CRS undergoing

Epithelial damage and basement membrane thickening

The demographics of the patients are shown in Table II. All patients with CRS demonstrated epithelial damage (Fig 2). In fact, 91% (20/22) of patients with CRS had substantial areas of the sinonasal epithelium completely eroded away (stage 3) down to the level of the basement membrane, whereas 9% (2/22) had only the upper layers eroded away (stage 2).

Basement membrane thickening was pathologic in all (22/22) of the patients with CRS. In 95% (21/22) of the patients with CRS, substantial areas of

Discussion

The predominantly eosinophilic inflammation present in CRS is recognized as playing an important role in the pathogenesis of CRS.1, 11 Because less than half of the patients with CRS in this study and in prior studies have elevated specific IgE or positive skin tests, this eosinophilic inflammation is not likely driven by an IgE mechanism. Furthermore, the eosinophilic inflammation is clearly heterogeneous in any given specimen; therefore, careful evaluation of numerous sites of the same

Acknowledgements

We thank Ms Debra Ward for secretarial assistance and Ms Cheryl Adolphson for editorial assistance.

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Supported by grants from the National Institutes of Health (AI 49235, AI 50494-P3) and from the Mayo Foundation.

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