In contrast to early-stage COPD, proceeding bronchial epithelial remodeling in COPD patients has been shown to be associated with a progressive loss of bronchial epithelial pIgR expression ultimately resulting in localized SIgA deficiency in airways of advanced COPD lungs48 which was mechanistically linked to TGFβ149. This evidence concerns the gene PIGR and chronic obstructive pulmonary disease.