Circulating monocytes expressing senescence‐associated features are enriched in COVID‐19 patients with severe disease

Accurate biomarkers for predicting COVID‐19 severity have remained an unmet need due to an incomplete understanding of virus pathogenesis and heterogeneity among patients. Cellular senescence and its pro‐inflammatory phenotype are suggested to be a consequence of SARS‐CoV‐2 infection and potentially drive infection‐dependent pathological sequelae. Senescence‐associated markers in infected individuals have been identified primarily in the lower respiratory tract, while little is known about their presence in more easily accessible bio‐specimens. Here, we measured the abundance of senescence‐associated signatures in whole blood, plasma and peripheral blood mononuclear cells (PBMCs) of COVID‐19 patients and patients without an infection. Bulk transcriptomic and targeted proteomic assays revealed that the level of senescence‐associated markers, including the senescence‐associated secretory phenotype (SASP), is predictive of SARS‐CoV‐2 infection. Single‐cell RNA‐sequencing data demonstrated that a senescence signature is particularly enriched in monocytes of COVID‐19 patients, partially correlating with disease severity. Our findings suggest that monocytes are prematurely induced to senescence by SARS‐CoV‐2 infection, might contribute to exacerbating a SASP‐like inflammatory response and can serve as markers and predictors for COVID‐19 and its sequelae.