IL13 and chronic obstructive pulmonary disease: In this respect, IL-13 may also play a role in COPD since the inducible overexpression of IL-13 in adult murine lungs leads to alveolar enlargement, lung enlargement and an enhanced compliance and mucus cell metaplasia [75] with activation of MMP-2, -9, -12, -13, and -14 and cathepsins B, S, L, H, and K in this model.