Heterogeneity of neutrophils and inflammatory responses in patients with COVID-19 and healthy controls

We undertook an unbiased, detailed analysis of neutrophil responses in adult patients with COVID-19 and healthy controls, to determine whether distinct neutrophil phenotypes could be identified during infections compared to the healthy state. Single-cell RNA sequencing analysis of peripheral blood neutrophils from hospitalized patients with mild or severe COVID-19 disease and healthy controls revealed distinct mature neutrophil subpopulations, with relative proportions linked to disease severity. Disruption of predicted cell-cell interactions, activated oxidative phosphorylation genes, and downregulated antiviral and host defense pathway genes were observed in neutrophils obtained during severe compared to mild infections. Our findings suggest that during severe infections, there is a loss of normal regulatory neutrophil phenotypes seen in healthy subjects, coupled with the dropout of appropriate cellular interactions. Overall design: we recruited adult subjects hospitalized with mild or severe SARS-CoV-2 infections, in order to examine how neutrophil phenotypes changed based upon the severity of infection over time, compared to healthy adults. we employed single-cell RNA sequencing (scRNA-seq) analysis of the peripheralneutrophil immune response to SARS-CoV-2. Fresh neutrophils from human subjects is needed in order to determine whether mature neutrophils have the ability to adopt distinct phenotypes, and how these phenotypes change during clinically significant respiratory infections such as SARS-CoV-2.