TY - JOUR T1 - Repeated daily exposure to 2 ppm nitrogen dioxide upregulates the expression of IL-5, IL-10, IL-13, and ICAM-1 in the bronchial epithelium of healthy human airways JF - Occupational and Environmental Medicine JO - Occup Environ Med SP - 892 LP - 896 DO - 10.1136/oem.60.11.892 VL - 60 IS - 11 AU - S Pathmanathan AU - M T Krishna AU - A Blomberg AU - R Helleday AU - F J Kelly AU - T Sandström AU - S T Holgate AU - S J Wilson AU - A J Frew Y1 - 2003/11/01 UR - http://oem.bmj.com/content/60/11/892.abstract N2 - Background: Repeated daily exposure of healthy human subjects to NO2 induces an acute airway inflammatory response characterised by neutrophil influx in the bronchial mucosa Aims: To assess the expression of NF-κB, cytokines, and ICAM-1 in the bronchial epithelium. Methods: Twelve healthy, young non-smoking volunteers were exposed to 2 ppm of NO2/filtered air (four hours/day) for four successive days on separate occasions. Fibreoptic bronchoscopy was performed one hour after air and final NO2 exposures. Bronchial biopsy specimens were immunostained for NF-κB, TNF-α, eotaxin, Gro-α, GM-CSF, IL-5, -6, -8, -10, -13, and ICAM-1 and their expression was quantified using computerised image analysis. Results: Expression of IL-5, IL-10, IL-13, and ICAM-1 increased following NO2 exposure. Conclusion: Upregulation of the Th2 cytokines suggests that repeated exposure to NO2 has the potential to exert a “pro-allergic” effect on the bronchial epithelium. Upregulation of ICAM-1 highlights an underlying mechanism for leucocyte influx, and could also explain the predisposition to respiratory tract viral infections following NO2 exposure since ICAM-1 is a major receptor for rhino and respiratory syncytial viruses. ER -