MUC5B and idiopathic pulmonary fibrosis: When all epithelial lineages were aggregated (Figure 5C), however, there was a disease-dependent increase in accessibility at the MUC5B promoter (fold change for MUC5B chromatin accessibility in IPF versus control epithelial cells = 1.52, Bonferroni adjusted P value (Padj) = 7.1 × 10–44, based on logistic regression).