Single-cell analysis reveals bronchoalveolar epithelial dysfunction in COVID-19 patients

Dear Editor,In 2019,a zoonotic coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)was identified as the causative agent of Coronavirus Disease 2019(COVID-19).As of 8 June 2020,the World Health Organization(WHO)has reported 6,912,751 globally confirmed cases with 400,469 deaths.Although generally causes mild disease,SARS-CoV-2 infection can result in serious outcomes,including acute lung injury(ALI)and acute respiratory distress syndrome(ARDS),the leading cause of mortality in patients with comorbidities.Recent autopsy studies of COVID-19 patients revealed mononuclear infiltration and excessive production of mucus in the infected lung,especially in the damaged small airways and alveoli(Bian and Team,2020;Liu et al.,2020).