Despite intensive research efforts all over the world, how the SARS-CoV-2 virus destroys lung function and why this happens only in selected patients remains incompletely understood. We have therefore collected lung and blood samples of COVID-19 patients hospitalized for severe disease at the start of the COVID-19 pandemic. These samples have been analysed via single cell RNA sequencing, a recently developed technology that yields unprecedented insights into how the virus interacts with cells of the immune system in the lungs of COVID-19+ patients. Unexpectedly, we found that lungs of severely ill COVID-19 patients are infiltrated by Tfh cells, a subset of white blood cells that normally exert their function in the lymph node where they support B cell differentiation. With this project we aim to conduct additional functional assays to understand how these cells impact on COVID-19 disease severity.

Importantly, although the  interest in SARS-CoV-2 research is waning, the virus is not eradicated. New variants are still emerging and the risk of a new pandemic is not eliminated. Therefore, obtaining a better insight into how the virus interacts with our immune system in the lungs, which is the focus of this project, will be essential to be better prepared for future pandemics.