Histological analysis
Mucosal tissues from patients with CRS were obtained from nasal polyps
or the uncinate process. Tissues were immediately fixed in 10%
formalin, embedded in paraffin, and cut into thin sections. Sections
were stained with hematoxylin–eosin to differentiate CRS into various
eosinophilic phenotypes. Representative HE staining pictures of Non-eCRS
and ECRS were shown in Supplementary Fig.1A. The numbers of eosinophils
and total inflammatory cells beneath the epithelial surface per high
power field (HPF) (x400) were quantified by 2 independent researchers
and the percentage of eosinophils in total infiltrating inflammatory
cells (eosinophils percentage) was calculated. Five fields were randomly
selected, then the average percentage was analyzed. According to
previous studies of ECRS in China, we defined ECRS as eosinophil
percentage exceeding 10%, as proposed by Cao et
al32.
At the same time, the histological patterns of each patient were
evaluated according to histopathological characteristics referring to
basement membrane thickening, goblet cell hyperplasia, subepithelial
edema, submucous gland formation, eosinophils infiltration, fibrosis and
atypical cells by 2 independent researchers. Briefly, there were four
main classifications: edematous, eosinophilic CRS with a great number of
eosinophils, goblet cell hyperplasia, thickening of the basement
membrane; CRS characterized by numerous seromucous glands and ductal
structures; fibroinflammatory CRS, lack of stromal edema and goblet cell
hyperplasia, frequently showed evident dilated vessels and a great
number of fibrocytes; atypical CRS with distinct stromal cells that were
bizarre and atypical. Representative HE stainings of the histologic
pattern was shown in Supplementary Fig. 1B.