The mucociliary apparatus is modified in asthmatic patients, as evidenced by an increase in the number of goblet cells with increased mucin gene expression, an increase in MUC5AC protein relative to MUC5B, and a reduction in ciliated cell numbers.71, 72, 73 In addition, decreased ciliary beat frequency, dyskinesia, and ciliary disorientation have been reported in patients with severe asthma.74 Here, MUC5AC is linked to asthma.