High levels of CD40-CD40L and ICOS-ICOSL expression in nasal tissue are linked to high eosinophil levels and disease activity in CRS patients
Our further findings showed that the expression levels of CD40 (r=0.6291, p=0.0003), CD40L (r=0.5820, p=0.0023), ICOS (r=0.6149, p=0.0030), ICOSL (r=0.5127, p=0.0063) in nasal polyps of CRS patients were all significantly correlated with tissue eosinophil count (Fig. 5A). Consistently, our immunofluorescence co-staining results showed that a great number of CD40-positive cells were eosinophils in ECRS nasal tissue (Fig. 5B). Most eosinophils are also ICOSL-positive in nasal polyps of ECRS patients (Fig. 5C).
Furthermore, both increased tissue CD40 and CD40L expression in our CRS patients were linked to higher blood eosinophil count (r =0.5066, p=0.0059, Fig. 6A; r =3893, p=0.0544, Fig. 6B). Similarly, ICOS and ICOSL-positive cell numbers in tissue were strongly, positively correlated with blood eosinophil count (r=0.6419, p=0.0017, Fig. 6C; r=0.6694, p=0.0001, Fig. 6D). Besides, nasal tissue ICOS and ICOSL expression levels correlated with disease activity assessed by Lund-Mackay score (r=0.4714, p=0.0416, Fig. 6E; r=0.4047, p=0.0498, Fig. 6F).