[Features and treatment of immediate and late asthmatic responses]

In atopic asthma, the antigen-induced airway reaction consists of three phases; (1) immediate asthmatic response, LAR, (2) late asthmatic response, LAR, and (3) post-late asthmatic response, pLAR. Election microscopic examination of biopsy specimens of the bronchial mucosa, and examination of desquamated bronchial epithelial cells in sputum after antigen challenge showed that eosinophil infiltration in the bronchial epithelium contributes to airway hyperresponsiveness in asthma. Since LAR and pLAR are considered to be inflammatory responses caused by eosinophil infiltration, suppression of the inflammation by anti-allergic drugs and corticosteroids is effective in the treatment of LAR and pLAR. PAF antagonists and immunosuppressive agents have been investigated for their use in asthma treatment because of their anti-inflammatory effects. In addition to these anti-inflammatory agents, an antagonist of leukotriene C4 and D4 which are potent bronchoconstricting mediators has been shown to suppress both IAR and LAR, suggesting its possible use in asthma treatment.