The main results presented previously in COPD animals infected with Pneumocystis documented a synergic increment of inflammation markers such as TNFα, IL6, IL8 and Cxcl2, an increment of mucus markers, such as Muc5ac and Muc5b, and Th2 transcription factors associated with mucus secretion, such as FoxA3 and Spdef. Here, MUC5AC is linked to chronic obstructive pulmonary disease.