Cigarette smoke-exposed COPD HBEC show decreased E-cadherin and ZO-1 expression and reduced transepithelial electric resistance (TEER) when compared with smokers without COPD (Milara et al, 2013; Heijink et al, 2014) and after 4 wk culture, the COPD ALI-AE displays altered lineage differentiation, decreased pIgR expression, and EMT (Gohy et al, 2014, 2015, 2019), along with increased cytokine release (Schneider et al, 2010). Here, PIGR is linked to chronic obstructive pulmonary disease.