Research led by investigators at Ghent University in Belgium showed dysregulation of the complement part of the immune system, regulated by the pro-inflammatory protein interleukin (IL)-6, is a key driver of severe COVID-19 and a good target for drugs to treat the effects of the disease. Writing in the Aug. 23, 2023, issue of Science Translational Medicine, the researchers also described a cellular map of the alterations seen in the complement system during COVID-19 related respiratory deterioration for use in future research.