A few studies have shown that RSV infection can decrease type I IFN levels, increase IL‐17 and IL‐23 secretion, upregulate mucin gene expression (MUC5AC and GOB5), and destroy ciliated epithelial cells in COPD models, leading to mucus retention and alveolar cavity enlargement.145. The gene discussed is IL17A; the disease is chronic obstructive pulmonary disease.