Features of airway remodeling and eosinophilic inflammation in chronic rhinosinusitis: is the histopathology similar to asthma?
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.


CONCLUSIONS
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.
Ponikau
Jens U
JU
Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minn 55905, USA.
Sherris
David A
DA
Kephart
Gail M
GM
Kern
Eugene B
EB
Gaffey
Thomas A
TA
Tarara
James E
JE
Kita
Hirohito
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000473:pathology*; D001485:Basement Membrane / Q000473:pathology; D004802:Eosinophilia / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020545:Respiratory Mucosa / Q000473:pathology*; D012220:Rhinitis / Q000473:pathology*; D012852:Sinusitis / Q000473:pathology*