Soehnlein, O.
The infiltration of solid organs with neutrophils during pathogen infiltration or sterile injury typically comes with damage to the host cells. Indeed, excessive neutrophil infiltration associates with tissue destruction and long-term impairment of organ function across various clinical scenarios including liver and kidney failure, stroke, myocardial infarction and acute lung injury1. Mechanistically, such collateral damage can be the result of various neutrophil-dependent effector functions, including the release of reactive oxygen species (ROS), cytotoxic granule proteins and neutrophil extracellular traps1. Although these are central mechanisms in inflammation, there is currently no imaging modality available that enables the detection of these processes or molecules with high sensitivity and specificity. Quantification of neutrophils in tissues may therefore be the closest approximation to study neutrophil-dependent immune responses. In this issue of Nature Cardiovascular Research, Bouvain et al.2 develop and validate a CD177-targeted tracer that enables longitudinal visualization of neutrophil dynamics in vivo.