When smokers with or without COPD were grouped together (Figure 2a,b) there was a significant inverse correlation between post-bronchodilator FEV1% predicted values and CRIM1+ cells (cells/mm2) (Figure 2a) and between post-bronchodilator FEV1% predicted values and chordin+ cells (cells/mm2) in the lamina propria (Figure 2b). Here, CHRD is linked to chronic obstructive pulmonary disease.