As for the mechanisms of increased asthma exacerbation in eosinophil-predominant asthma, there was a correlation between the AHR and MBP concentration and the ratio of eosinophils and airway epithelial cells in bronchoalveolar lavage fluid (BALF) [18], suggesting that MBP-induced injury of the airway epithelial cells may be involved in the development of AHR and thus the exacerbation of asthma. This evidence concerns the gene MBP and asthma.