Background: Defective type I interferon (IFN) production and consequent enhanced viral load have already been described in the bronchial epithelium of atopic asthmatic patients. The aim of the present study was to evaluate rhinovirus (RV) mediated IFN-β expression and RV load in upper airway epithelial cells of individuals with or without allergic rhinitis and asthma. Methods: Primary nasal epithelial cells were collected with the use of a curette from adults with allergic rhinitis (n=7), allergic rhinitis (n=7) and asthma and from non-allergic, healthy volunteers (n=7). Cells were exposed to 1 multiplicity of infection of RV1b or control medium. Culture supernatants and total RNA were harvested after incubation for 6-72h. RV-induced cytotoxicity was evaluated by a crystal violet colorimetric assay and by measuring lactate dehydrogenase (LDH) release in cell supernatants. RV-mediated RANTES release in cell supernatants was determined with the use of ELISA. In order to investigate viral load we evaluated the intracellular RV RNA levels by real-time PCR. RV-induced IFN-β expression was also measured by real-time PCR.
