atients with COVID-19 exhibit a broad spectrum of disease progression, with 81% showing mild, moderate or no symptoms; 14% showing severe symptoms; and 5% experiencing critical disease with high mortality risk 1 . The risk of developing severe or critical disease has been associated with advanced age 1,2 , comorbidities 1,2 , hyperactivation of the immune system 3,4 , sex 1,2 and other factors. However, an understanding of these risk factors at the molecular and cellular levels is in its infancy.In this study, we investigated the immune response in patients with COVID-19 by single-cell RNA sequencing (scRNA-seq) of nasopharyngeal and bronchial samples to identify molecular correlates of disease severity. Two recent studies applied scRNA-seq to bronchioalveolar lavage fluid samples from patients with COVID-19 and provide an extensive characterization of the inflammatory immune phenotype in the lower respiratory tract 5,6 . However, SARS-CoV-2 and other coronaviruses infect and replicate in both COVID-19 severity correlates with airway epithelium-immune cell interactions identified by single-cell analysis

BACKGROUND & AIMS: Molecular evidence of cellular heterogeneity in the human exocrine pancreas has not been yet established because of the local concentration and cascade of hydrolytic enzymes that can rapidly degrade cells and RNA upon pancreatic resection. We sought to better understand the heterogeneity and cellular composition of the pancreas in neonates and adults in healthy and diseased conditions using single-cell-sequencing approaches. METHODS: We innovated single-nucleus RNA-sequencing protocols and profiled more than 120,000 cells from pancreata of adult and neonatal human donors. We validated the single-nucleus findings using RNA fluorescence in situ hybridization, in situ sequencing, and computational approaches. RESULTS: We created the first comprehensive atlas of human pancreas cells, to our knowledge Q9 , including epithelial and nonepithelial constituents, and uncovered 3 distinct acinar cell types, with possible implications for homeostatic and inflammatory processes of the pancreas. The comparison with neonatal single-nucleus-sequencing data