CD40 and congenital rubella syndrome: 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), and ICOSL (r = 0.5127, p = 0.0063) in nasal tissues of patients with CRS were all significantly correlated with tissue eosinophil count (Figure 5A).