Finney LJ, Glanville N, Farne H, et al. - Researchers sought to determine how inhaled corticosteroids (ICS) affect pulmonary expression of the SARS-CoV-2 viral entry receptor angiotensin-converting enzyme (ACE)-2. They investigated this effect in vitro in human airway epithelial cell cultures and in vivo in mouse models of ICS administration. ICS administration led to reduction in ACE2 expression in mice, an effect that was reversed by exogenous interferon-β administration and Ifnar1 −/− mice had decreased ACE2 expression, implying mechanistical contribution of type I interferon to this effect. COPD airway epithelial cell cultures and mice with elastase-induced COPD-like changes showed attenuation in expression of ACE2 in correlation with ICS administration. Also, reduced sputum expression of ACE2 was observed among COPD patients taking ICS vs non-ICS users. Findings thereby suggest the reduced expression of the SARS-CoV-2 entry receptor ACE2 in correlation with ICS therapies in COPD. Hence, this effect may contribute to modified susceptibility to COVID-19 in patients with COPD.