IFNL2 and chronic obstructive pulmonary disease: Consistent with our findings that type I IFN negatively regulates mucin production during RV infection in mice, we observed that peak sputum cell expression of IFNβ, IFNλ2/3 and peak sputum concentrations of CXCL10/IP-10 protein negatively correlated with sputum MUC5AC during virus-induced COPD exacerbation (Fig. 7h).