IL13 and chronic obstructive pulmonary disease: However, different from the observations in control, FOXA2 expression did not decreased during the IL-13-induced goblet cell differentiation of cells from patients with COPD (Additional file 4: Figure S3b), whereas loss of DNA methylation in the FOXA2 promoter was observed (CpG number 14, from 12% at day 0 to 8% at day 28; CpG number 15, from 15% at day 0 to 11% at day 28, Additional file 6: Figure S5).