Upon HRV infection, enhanced Muc5Ac was detected in sloughed cells of both cultures compared with corresponding mock infected cultures (7 ± 4 vs. 43 ± 17 and 16 ± 8 vs. 113 ± 15 for healthy and COPD cultures, respectively, both P < 0.01; Figures 4A,B). Here, MUC5AC is linked to chronic obstructive pulmonary disease.