Other studies have demonstrated decreased levels of uteroglobin, an anti-inflammatory protein secreted by Clara cells, in the BAL[49], pooled nasal lavage fluid[21], and serum[50] of healthy smokers and in the bronchial epithelium of former smokers with COPD undergoing lung transplantation[51]. Here, SCGB1A1 is linked to chronic obstructive pulmonary disease.