Background: Clara cell 10-kD protein (CC10) is well known to be an immuno-suppressive protein secreted from airway epithelial cells after inflammatory stimulation and is involved in the development of allergic disorders. Although histamine H1 receptor antagonists are used for the treatment of allergic disorders, the influence of the agents on CC10 production is not well understood. In the present study, we examined the influence of a histamine H1 receptor antagonist, fexofenadine hydrochloride (FEX) on CC10 production in vitro and in vivo.
Methods: Nasal epithelial cells (5 x 10(6) cells/ml) were stimulated with 20 ng/ml TNF-alpha in the presence of various concentrations of FEX for 24 hours. CC10 levels in culture supernatants were examined by ELISA. Patients with Japanese cedar pollinosis were treated orally with FEX twice a day at a single dose of 60 mg for two weeks during Japanese cedar pollen season (February 2011 to April 2011). CC10 levels in nasal secretions were also examined by ELISA.
Results: The addition of FEX into cell cultures caused increase in CC10 production induced by TNF-alpha stimulation, and the minimum concentration that caused significant increase was 200 ng/ml. Oral administration of FEX also increased CC10 levels in nasal secretions from pollinosis patients along with attenuation of clinical symptoms.
Conclusion: The ability of FEX to enhance CC10 production may account, at least in part, for the clinical efficacy of the agent in allergic disorders, including allergic rhinitis.