Datasets including LTSs with (LTS+; triangles) and without (LTS−; squares) COPD compared with HNSs (circles) are shown as follows: (A) level of MUC5AC in processed (filtration and centrifugation) BAL fluid samples from Material 1; (B) level of MUC5AC in unprocessed (no filtration and no centrifugation) BAL fluid samples from Material 2; (C) level of MUC5AC in processed (filtration and centrifugation) BAL fluid samples from Material 2 and (D) proportion (%) of MUC5AC present in large complexes from Material 2. Each data point represents the mucin concentration in one subject. Solid (black) symbols denote subjects without colonization by bacterial pathogens whereas open (white) symbols denote the subjects with this colonization in Material 2. Horizontal bold lines depict the median value for each study group. Analytical statistics are shown according to Kruskal–Wallis one-way ANOVA on ranks.