MMP9 and asthma: In ovalbumin- and Aspergillus fumigatus-induced asthma, (i) Mmp9−/− mice show an interrupted migration of eosinophils and neutrophils into the bronchoalveolar lavage fluid and a considerable accumulation of cells with apoptotic phenotype in the lungs; (ii) Mmp2−/− mice show an interrupted trafficking of eosinophils into the bronchoalveolar lavage fluid, a considerable accumulation of lung cells with an apoptotic phenotype, and augmented predisposition to asphyxiation; (iii) Mmp9−/−/Mmp2−/− mice show inflammatory cell egression mainly controlled by MMP-9.