CC16 in allergy and allergic inflammation

Clara cell 16-kDa (CC16) is an anti-inflammatory protein mainly produced in the lung epithelium by Clara cells. Patients with asthma have lower levels of CC16 in bronchoalveolar lavage fluid and serum compared with healthy controls. In OVA-sensitised and challenged CC16-deficient mice, eosinophilia and the production of Th2 cytokines in the lung is higher compared with wild-type mice. Moreover, CC16 has been shown to inhibit cytokine production from a murine Th2 cell line and to inhibit the migration of rabbit neutrophils. CC16 also binds to the mast-cell derivative PGD2 and inhibits the stimulation of the DP1 receptor. For this reason, the first aim was to investigate whether CC16 levels in nasal lavage would be lower in children with allergic rhinitis compared with healthy controls. Our second aim was to evaluate whether a low level of CC16 in plasma early in life is involved in the development of asthma, eczema and allergic rhinitis (ARC). Our third aim was to examine whether CC16 would inhibit Th2 differentiation and if CC16 would inhibit PGD2 and fMLF-induced eosinophil and neutrophil migration. CC16 was measured in nasal lavage samples from children with and without birch-polle