ICOSL expression is significantly higher in nasal tissue of CRS patients with edematous pattern
All CRS patients were also classified into different histopathological pattern. We found that the percentage of mere hyperplasia (38.1%) and fibrotic pattern (33.3%) were overwhelming in Non-eCRS, while none of these two types were observed in ECRS (Fig. 3A). In group ECRS, pattern edematous combined with fibrotic accounted for the largest proportion (40.0%), followed by edematous plus hyperplasia pattern (30.0%) and edematous pattern (30.0%), which were all characterized by edema (Fig. 3A). When the six patterns were combined into three types, the edematous pattern was seen in 28.6% of Non-eCRS patients and 100.0% in patients of ECRS. Whereas, the proportions of fibrotic and hyperplasia patterns were both slightly lower in ECRS than Non-eCRS, respectively. (40.0% vs 47.6%, 30.0 vs 47.6%, Fig. 3B).
According to the great difference of the proportion in edematous subtype and merely little variation of that in hyperplasia and fibrotic subtypes between ECRS and Non-eCRS, we thus only examined CD40-CD40L and ICOS-ICOSL expression in the histopathological subtype of edema. Results showed that the expression levels of ICOSL (59.21 ± 12.76 vs 16.16 ± 2.89, P=0.0319, Fig. 3C) were significantly increased in the nasal tissue of CRS patients with edematous pattern compared with that in Non-edematous pattern CRS patients. The number of ICOS or CD40 positive cells was also higher in edematous pattern nasal tissue compared with that in the nasal polyps of Non-edematous pattern CRS patients, but no significant difference was observed (Fig. 3D-E). But in contrast, there was no obvious difference in tissue CD40L expression between edematous and Non-edematous pattern CRS patients (Fig. 3F).