Airway cytokine responses to acute and repeated stress in a murine model of allergic asthma

Although stress is known to exacerbate asthma, the underlying mechanisms are unclear. Using a murine model of allergic asthma, Th1 (interleukin [IL]-2 and gamma-interferon [IFN-gamma]) and Th2 (IL-4 and IL-5) airway cytokine responses and Th1 :Th2 cytokine ratios to acute and repeated stress were examined in bronchoalveolar lavage fluid (BALF). Asthmatic mice showed significantly higher IL-4 level and Th2 predominance, compared with healthy mice. To acute stress, asthmatic mice significantly increased IL-4 but decreased IFN-gamma levels favoring Th2 predominance, whereas healthy mice significantly decreased IL-4 level favoring Th1 predominance in BALF. To repeated stress, asthmatic mice significantly decreased IFN-gamma, IL-4 and IL-5 levels overall favoring Th1 predominance, whereas healthy mice basically maintained the same response profile shown to acute stress. These findings suggest that a significant shift toward Th2 predominance in asthmatic mice under acute stress may be a mechanism underlying exacerbation of asthma. (C) 2009 Elsevier B.V. All rights reserved.