[The pathogenesis and therapy of virus infection-induced senile bronchial asthma]

We investigated the pathogenesis and therapy of virus infection-induced senile bronchial asthma in vitro. To examine the effects of rhinovirus infection on the production of cytokines and intercellular adhesion molecule-1 (ICAM-1), human tracheal epithelial cells and submucosal gland cells were cultured, and infected with human rhinovirus. Rhinovirus upregulated the production of interleukin (IL)-1 beta, IL-6, IL-8, tumor necrosis factor (TNF)-alpha in supernatants of epithelial cells and submucosal-gland cells, and IL-1 alpha and granulocyte macrophage colony-stimulating factor (GM-CSF) in supernatants of submucosal gland cells. Rhinovirus upregulated the expression of ICAM-1 mRNA. Rhinovirus infection also increased epithelial permeability. These events may be important for the spread of airway inflammation after rhinovirus infection. Furthermore, we studied the effects of dexamethasone and erythromycin on the modulation of virus infection and induction of cytokines and ICAM-1 in tracheal epitherial cells. Both of them reduced viral titers of rhinovirus type 14, a major group rhinovirus, and cytokine production of supernatants, and ICAM-1 mRNA expression in the cells. Because it is known that acidic conditions by proton pumps are needed for rhinovirus entry into the cells, we studied the effects of H+ ATPase inhibitor bafilomycin A1. Bafilomycin A1 reduced the virus titers of both rhinovirus type 2 and 14 in supernatants. These findings in our in vitro study suggest that dexamethasone, erythromycin and bafilomycin A1 may inhibit rhinovirus infection and modulate airway inflammation induced by rhinovirus infection.